Skip to main content

Full text of "Psychological review"

See other formats 


FT- 

n 

PSYCHOLOGICAL  REV1E  W  PUBLICA  TIONS 


n 

THE 

P  sychological  Review 

EDITED  BY 

JOHN  B.  WATSON,  JOHNS  HOPKINS  UNIVERSITY 
HOWARD  C.  WARREN,  PRINCETON  UNIVERSITY  (Index"} 

JAMES  R.  ANGELL,  UNIVERSITY  OF  CHICAGO  (Monographs)  AND 

SHEPHERD  I.  FRANZ,  GOVT.  HOSP.  FOR  INSANE  (Bulletin) 

ADVISORY  EDITORS 

R.  P.  ANGIER,  YALE  UNIVERSITY;  MARY  W.  CALKINS,  WELLESLEY  COLLEGE;  RAY- 
MOND DODGE,  WESLEYAN  UNIVERSITY;  H.  N.  GARDINER,  SMITH  COLLEGE;  JOSEPH 
JASTROW,  UNIVERSITY  OF  WISCONSIN;  C.  H.  JUDD,  UNIVERSITY  OF  CHICAGO;  ADOLF 
MEYER,  JOHNS  HOPKINS  UNIVERSITY  ;  HUGO  M0NSTERBERG,  HARVARD  UNIVERSITY  ; 
W.  B.  PILLSBURY,  UNIVERSITY  OF  MICHIGAN  ;  C.  E.  SEASHORE,  UNIVERSITY  OF  IOWA  ; 
G.  M.  STRATTON,  UNIVERSITY  OF  CALIFORNIA  ;  E.  L.  THORNDIKE,  COLUMBIA  UNIVERSITY 


VOLUME  XXII,    1915 


1 


PUBLISHED   BI-MONTHLY   BY 

PSYCHOLOGICAL  REVIEW  COMPANY 

41  NORTH   QUEEN   ST.,  LANCASTER,  PA. 
AND  PRINCETON,  N.  J, 

Entered  as  second-class  matter  July  13,  1897,  at  the  post-office  at  Lancaster,  Pa.,  under 
Act  of  Congress  of  March  3,  1879. 


PRESS  OF 

THE  NEW  ERA  PRINTING  COMPANY 
LANCASTER.  PA. 


CONTENTS  OF  VOLUME  XXII 

January. 

A  Revision  of  Imageless  Thought.     R.  S.  WOODWORTH,  i. 

A  New  Measure  of  Visual  Discrimination.     KNIGHT  DUNLAP,  28. 

An  Electro-Mechanical  Chronoscope.    JOHN  W.  TOOD,  36. 

From  the  University  of  California  Psychological  Laboratory: 

XVIII.  Practice  in  Associating  Color-Names  with  Colors.    WARNER  BROWN,  45. 
XIX.  The  Apparent  Rate  of  Light  Succession  as  Compared  with  Sound  Suc- 
cession.    BERTHA  VON  DER  NIENBURG,  56. 

XX.  A  Memory  Test  with  School  Children.    ARTHUR  H.  CHAMBERLAIN,  71. 
XXI.  Practice  in  Associating  Number-Names  with  Number-Symbols.    WAR- 
NER BROWN,  77. 
XXII.  Incidental  Memory  in  a  Group  of  Persons.    WARNER  BROWN,  81. 

March. 

A  Proposed  Classification  of  Mental  Functions.     GEORGE  A.  COE,  87. 

Color  Theory  and  Realism.     KNIGHT  DUNLAP,  99. 

Point  Scale  Ratings  of  Delinquent  Boys  and  Girls.     THOMAS  H.  RAINES,  104. 

A  Preliminary  Study  of  the  Deficiencies  of  the  Method  of  Flicker  for  the  Photometry 

of  Lights  of  Different  Colors,  Part  I.     C.  E.  FERREE  and  GERTRUDE  RAND,  no. 
Discussion : 

The  Functions  of  Incipient  Motor  Processes.     S.  BENT  RUSSELL,  163. 

May. 

The  Theory  and  Practice  of  the  Artificial  Pupil.    LEONARD  T.  TROLAND,  167. 
The  Temporal  Relations  of  Meaning  and  Imagery.    T.  V.  MOORE,  177. 
The  Shortest  Perceptible  Time-Interval  Between  Two  Flashes  of  Light.     KNIGHT 
DUNLAP,  226. 

July. 

An  Experimental  Contribution  to  the  Investigation  of  the  Subconscious.    LILLIEN 

J.  MARTIN*  251. 

Emotional  Poetry  and  the  Preference  Judgment.    JUNE  E.  DOWNEY,  259. 
An  Experiment  in  Association.     C.  G.  BRADFORD,  279. 
A  Note  on  the  Effect  of  Rhythm  on  Memory.     H.  F.  ADAMS,  289. 
Diagnostic  Values  of  Some  Performance  Tests.    THOMAS  H.  RAINES,  299. 
Processes  Referred  to  the  Alimentary  and  Urinary  Tracts:  A  Qualitative  Analysis 

E.  G.  BORING,  306. 


September." 

The  Father  of  Modern  Psychology     FOSTER  WATSON,  333. 

An  Investigation  of  the  Law  of  Eye-Movements.     MILDRED  LORING,  354. 

Variability  in  Performance  During  Brief  Periods  of  Work.    A.  T.  POFFENBERGER,  JR., 

and  GLADYS  G.  TALLMAN,  371. 

The  Standardization  of  Knox's  Cube  Test.     RUDOLF  PINTNER,  377. 
The  Adequacy  of  the  Laboratory  Test  in  Advertising.    H.  F.  ADAMS,  402. 

iii 


iv  CONTENTS 

November. 

Reaction  to  the  Cessation  of  Stimuli  and  Their  Nervous  Mechanism.    HERBERT 

WOODROW,  423. 

A  Study  in  Simultaneous  and  Alternating  Finger  Movements.     H.  S.  LANGFELD,  453. 
Retinal  Factors  in  Visual  After-Movement.    WALTER  S.  HUNTER,  479. 
Experimental  Data  on  Errors  of  Judgment  in  the  Estimation  of  the  Number  of  Objects 

in  Moderately  Large  Samples,  with  Special  Reference  to  Personal  Equation. 

J.  ARTHUR  HARRIS,  490. 

Origin  of  Higher  Orders  of  Combination  Tones.    JOSEPH  PETERSON,  512. 
From  the  University  of  California  Psychological  Laboratory: 

XXIII.  Practice  in  Grading  and  Identifying  Shades  of  Gray.    WARNER  BROWN, 


Correction:  May,  1915,  p.  216,  line  2,  delete  "  in."  The  sentence  when  corrected 
should  read:  "  One  mental  process  is  the  meaning  of  another  mental  process  if  it  is 
that  other's  context." 


VOL.  XXII.  No.  i  January,  1915 


THE  PSYCHOLOGICAL  REVIEW 


A  REVISION  OF  IMAGELESS  THOUGHT1 

BY  R.  S.  WOODWORTH 

Columbia  University 

Several  years  ago  I  was  led  by  some  experiments  on 
voluntary  movement  to  conclude  that  an  act  might  be 
thought  of  without  any  representative  or  symbolic  image, 
and  further  study  led  me  to  extend  this  conclusion  to  other 
thoughts.  My  attention  was  soon  called,  in  a  review  of 
this  work  by  Angell,  to  previous  discussions  of  the  same 
question,  connected  with  Stout's  assertion  that  there  was 
nothing  psychologically  absurd  in  the  conception  of  image- 
less  thought.  Looking  into  the  contemporary  experi- 
mental literature,  I  then  made  the  acquaintance  of  Binet  and 
of  Watt,  Biihler  and  others  of  the  Kiilpe  school,  and  my 
own  work  soon  fell  into  insignificance  beside  these  extensive 
and  many-sided  contributions.  Even  the  merit  of  inde- 
pendent confirmation  was  not  specially  important  in  this 
case,  since  such  confirmation  was  forthcoming  even  from  those 
who,  like  Wundt,  were  not  at  all  in  sympathy  with  the  con- 
clusions of  the  imageless  thought  party.  It  appeared  that 
imageless  thought,  the  mere  gross  fact  of  observation,  had 
come  to  stay,  and  that  the  only  question  was  what  to  do  with 
it.  Some  psychologists  have  assigned  great  importance  to 
this  fact  as  a  demonstration  of  non-sensory  content,  while 
others  have  avoided  so  revolutionary  a  conclusion  by  ex- 
plaining the  fact  away  through  one  interpretation  or  another; 
others  again  have  accepted  the  fact  but  minimized  its  im- 
portance, treating  it  as  a  mere  limiting  case;  and  some,  while 

Address  of  the  President  before  the  American  Psychological  Association,  at 
Philadelphia,  December,  1914. 

I 


2  R.  S.   WOODWORTH 

accepting  the  gross  fact,  have  doubted  that  it  would  stand  the 
test  of  more  refined  introspection.  Meanwhile,  my  own 
views  have  been  maturing  as  the  result  of  continued  thought 
and  experiment,  and  the  time  is  perhaps  favorable  for  resum- 
ing the  offensive,  and  endeavoring  to  uncover  the  weaknesses 
of  the  negative  interpretations,  and  for  offering  a  conception 
of  the  matter  which  may  possibly  appear  superior  to  those 
hitherto  presented,  or  at  least  worthy  of  some  consideration. 
Of  the  interpretations  of  imageless  thought  which  explain 
the  fact  away  without  allowing  it  to  modify  existing  systems 
of  psychology,  the  most  important  is  that  of  Wundt.  It  will 
be  recalled  that  the  method  employed  by  the  Kiilpe  school  in 
studying  the  thought  processes  was  drastically  criticized  by 
Wundt,  who  objected  to  their  experiments  as  being  experi- 
ments in  appearance  only,  and  held  that  real  thinking  could 
not  be  done  to  order  in  the  laboratory.  He  himself  preferred 
to  rely  on  incidental  introspections  during  spontaneous 
thought,  and  in  fact  reports  such  observations  of  his  own.1 
"In  such  self-observations,"  he  writes,  "it  became  perfectly 
clear  to  me  that  the  thought  was  not  formed  during  the 
process  of  its  verbal  expression,  but  was  present  as  a  whole 
in  consciousness  before  the  first  word  was  reached.  At  first 
none  of  the  verbal  or  other  images,  which  subsequently 
appeared  in  running  through  the  thought  and  giving  it  ex- 
pression, was  present  in  the  focus  of  consciousness,  but  these 
parts  of  the  thought  appeared  successively  as  the  thought  was 
allowed  to  develop."  With  only  this  fact  in  mind,  he  admits, 
one  might  easily  be  led  to  regard  the  thought  as  a  unit  with 
a  distinctive  elementary  character.  But  quite  a  different 
conclusion  is  reached  when  other  facts  are  also  taken  into 
account,  that  of  the  narrowness  of  the  field  of  attention,  that 
of  the  existence  of  dim  content  in  the  background  of  con- 
sciousness, and  that  of  the  "total  feeling,"  itself  a  unit, 
though  generated  by  a  complex  of  images.  A  thought,  in 
Wundt' s  view,  is  essentially  a  complex  of  images,  but  these 
parts  of  the  thought  are  too  numerous  to  be  present  together 
in  the  field  of  attention.  They  are  present  at  first  only  in 

1  Psychologische  Studien,  1907,  3,  349. 


A  REVISION  OF  IMAGELESS  THOUGHT  3 

the  background  and  are  not  introspectively  visible;  but  as 
the  thought  is  dwelt  upon  and  expressed,  its  constituent 
images  come  successively  into  view.  What  then  was  the 
apparently  unitary  thought  with  which  the  process  started? 
This,  explains  Wundt,  was  a  "  total  feeling,"  generated  by 
the  complex  of  images  in  the  background,  and  itself  occupying 
for  an  instant  the  center  of  the  stage. 

It  is  obvious  that  such  a  position  is  almost  inexpugnably 
entrenched.  The  extremely  hypothetical  nature  of  the 
ground  renders  a  direct  attack  hopeless.  So  much  as  this 
may  be  ventured,  that,  if  the  words  expressing  a  thought  are 
really  its  constituent  parts,  it  is  curious  that  the  same  thought 
can  be  thought  in  different  words,  and  even  in  different 
languages,  and  still  more  curious  that  the  words  to  fit  the 
thought  are  not  always  at  hand.  Apparently,  the  same 
complex  may  be  composed  of  different  elements,  and  may 
exist  with  some  of  its  elements  lacking.  Further,  it  is  curious 
to  reflect  that  these  verbal  images  in  the  background  must 
somehow  be  present  simultaneously  and  yet  in  proper 
sequence,  since  otherwise  they  might  compose  quite  a  different 
thought  or  no  thought  at  all. 

But  the  principal  doubt  to  be  raised  concerns  the  "  total 
feeling."  This  unitary  feeling,  present  without  observable 
images,  and  "adequate  to  the  thought/'  would  almost  meet 
the  demands  of  the  opposing  party,  except  for  Wundt's 
insistence  on  its  being  a  feeling,  to  the  neglect  of  its  noetic 
character.  Certainly  it  is  not  a  feeling,  in  any  strict  sense, 
that  straightway  finds  expression  in  a  statement  of  fact. 
Wundt's  analysis  leaves  out  of  account  the  core  of  the  whole 
experience,  namely,  the  fact  or  supposition  which  was  sub- 
sequently expressed  in  a  sentence,  but  which  was  definitely 
and  clearly  present  in  mind  in  advance  of  the  words. 

Several  writers  have  called  attention  to  the  presence  of 
vague  or  apparently  irrelevant  imagery  in  moments  that 
would  otherwise  appear  imageless.  The  presence  of  kines- 
thetic  sensations,  habitually  unattended  to,  has  also  been 
shown  in  many  cases,  and  thus  we  have  become  wary  of 
asserting  that  a  given  moment  is  really  devoid  of  sensory 


4  R.  S.   WOODWORTH 

content.  Of  course,  no  one  has  ever  supposed  that  bodily 
sensation  could  be  absent  from  the  background  of  any  con- 
scious state,  but  it  has  been  thought  possible  to  distinguish 
between  irrelevant  content  and  content  related  to  the  topic 
of  thought.  We  must,  however,  recognize  the  probability 
that  apparently  irrelevant  sensations  and  images  sometimes 
enter  into  the  web  of  thinking.  Especially  has  the  attempt 
been  made  with  some  success  to  extend  the  James-Lange 
theory  of  emotions  to  cover  the  so-called  "  conscious  atti- 
tudes"; and  some  would  even  extend  it  to  cover  the  imageless 
awareness  of  definite  facts,  contending  that  every  thought 
has  its  own  peculiar  motor  expression,  and  that  the  sensations 
generated  by  the  movement  furnish  the  conscious  content 
of  the  thought;  but  no  one,  as  far  as  I  know,  has  found  em- 
pirical support  for  this  extreme  view. 

It  is  worth  remarking  that  the  presence  of  images  and 
sensations  in  many  or  most  moments  of  thinking  does  not 
disconcert  the  supporter  of  imageless  thought.  He  is  per- 
fectly willing  to  admit  that  such  content  is  often  or  even 
usually  present;  and  the  only  real  importance  of  a  few  well- 
attested  instances  of  thought  without  such  content  is  that 
they  furnish  him  his  most  direct  evidence  of  the  existence  of 
other  content.  His  main  contention  is  that  other  content 
exists,  and  that  it  is  the  most  essential  and  characteristic  of  all. 

But  some  psychologists,  while  admitting  the  occasional 
occurrence  of  imageless  thought,  deny  its  evidential  im- 
portance. It  is  merely  the  limiting  case,  they  say,  in  a 
continuous  gradation  from  thought  in  clear  images,  down 
through  thought  in  medium  and  dim  images,  to  thought  in 
images  at  or  near  the  zero  mark.  The  most  attractive  form 
of  this  interpretation  is  that  which  sees  in  the  graded  series 
the  progressive  automatization  of  a  thought  through  practise. 
When  the  thought  is  novel,  it  comes  with  abundant  sensory 
content,  but  as  it  grows  familiar  and  habitual  it  becomes  less 
sensuous,  that  is  to  say,  less  conscious,  until,  just  as  it  is 
about  to  become  automatic  and  unconscious,  it  still  shows  a 
feeble  spark  of  conscious  life;  and  this  feeble  spark  is  pounced 
upon  by  the  imageless  thoughter  and  rashly  heralded  forth 


A  REVISION  OF  IMAGELESS  THOUGHT  5 

as  proof  of  some  unrecognized  species  of  conscious  experience. 
In  reality,  imageless  thought  is  imageless  because  it  is  all  but 
unconscious.  This  genetic  interpretation  has  been  presented 
with  most  force  by  Titchener1  and  by  Book.2 

The  undoubted  attractiveness  of  this  conception  comes 
from  its  following  so  neatly  from  the  law  of  practise,  and  its 
deficiencies  arise  from  its  taking  account  of  only  one  side  of 
the  practise  effect.  There  is  much  in  practise  besides  the 
tendency  toward  automatism.  Seldom  does  the '  course  of 
training  consist  of  repeating  time  after  time  the  same  per- 
formance, only  with  increasing  smoothness  and  speed. 
Usually  the  process  begins  with  varied  and  tentative  reactions, 
and  advances  by  selection  and  elimination.  Moreover  new 
forms  of  reaction,  made  possible  by  the  progress  in  facility, 
make  their  appearance  in  the  course  of  training.  Thus  the 
perfected  act  omits  elements  present  at  the  start  and  contains 
elements  not  present  at  the  start,  and  may  be  an  entirely 
different  means  of  reaching  the  same  result.  If  therefore 
the  first  thinking  on  a  given  topic  is  fraught  with  imagery, 
while  the  practised  thought  on  the  same  topic  is  bare  of  im- 
ages, it  does  not  in  the  least  follow  that  the  imageless  thought 
is  a  condensation  of  the  imaginal.  It  may  be  a  more  econ- 
omical substitute.  The  imagery  present  at  the  start  may 
have  been  due  to  a  diffusion  of  excess  energy  such  as  is 
common  in  unpractised  acts,  or  it  may  have  furnished  a 
round-about  way  of  dealing  with  the  problem  and  have  given 
place  with  practise  to  the  more  direct  attack  represented  by 
the  imageless  thought. 

Practise  experiments  give  little  ground  for  believing  that 
a  series  of  part  acts,  by  simply  becoming  very  easy  and  swift, 
blend  together  into  a  total  act  in  which  the  parts  are  lost  to 
sight.  Rather  has  it  been  found  true  that  the  more  inclusive 
acts,  such  as  dealing  with  words  and  phrases  as  units,  in 
typewriting  and  telegraphy,  arise  suddenly  as  new  forms  of 
action,  in  the  progress  of  training,  and  themselves  make 
possible  a  great  increase  in  the  speed  of  the  partial  or  lower- 

1  "Experimental  Psychology  of  the  Thought  Processes,"  1909,  pp.  173,  183,  187. 

2  PSYCHOLOGICAL  REVIEW,  1910,  17,  381. 


6  R.  S.   WOODWORTH 

order  acts.  The  partial  acts  do  not  blend  to  produce  the 
inclusive  act,  but  the  latter  is  hit  upon  and  causes  the  former 
to  blend.  Attention  deserts  the  parts,  which  thus  become 
automatic;  but  attention  still  remains  keenly  alive,  being 
directed  to  the  more  inclusive  acts.  These  higher  acts  are 
real  units,  and  not  mere  blends;  they  are  clearly  conscious 
and  yet  not  in  imaginal  form;  indeed,  they  seem  the  very 
type  of  an  imageless  thought. 

Observations  of  new  ideas,  at  their  first  appearance  in  an 
individual,  would  be  of  interest  in  relation  to  the  interpreta- 
tion of  imageless  thought  as  exclusively  old  and  well-drilled 
thought.  In  the  hope  of  gathering  such  observations,  I  have 
sought  to  catch  myself  at  moments  when  some  new  idea 
germinated  in  my  mind.  Unfortunately,  opportunities  have 
not  presented  themselves  with  the  frequency  that  could  be 
desired;  but,  in  the  few  instances  that  I  have  collected  the 
experience  could  be  described  as  the  dawning  of  some  new 
meaning  in  things,  sometimes  with  scrappy  verbal  and  visual 
images,  sometimes  with  none  that  were  observable.  When 
they  occurred,  the  images  were  promptly  forgotten,  though 
the  thought  was  firmly  impressed  on  memory.  So  far  from 
accepting  the  view  that  imageless  thought  is  automatized 
thought,  I  should  be  inclined  to  believe  that  a  new  thought  is 
characteristically  imageless,  and  that  it  attaches  itself  second- 
arily to  a  word  or  other  convenient  symbol,  and  is  more  apt 
to  occur  with  an  image  when  it  is  somewhat  familiar  than 
when  it  is  new. 

Still  another  interpretation  of  imageless  thought,  or  of  the 
observations  that  purport  to  reveal  it,  presents  a  serious 
obstacle  to  our  progress.  Frequently  such  statements  as 
these  are  contained  in  the  subject's  retrospective  report:  "I 
thought  of  such  and  such  an  object,"  or,  "I  thought  that  such 
and  such  was  the  case,"  this  being  the  extent  of  the  subject's 
description  of  his  experience,  except  for  the  purely  negative 
statement  that  no  images  were  present.  The  objection  has 
been  raised  by  Diirr,1  von  Aster,2  and  Titchener,3  that  in 

1  Zeitschrift  f.  Psychol.,  1908,  49,  313-340. 

2  Ibid.,  56-107. 

3  Op.  cit.,  p.  147. 


A  REFISION  OF  IMAGELESS   THOUGHT  7 

such  reports  the  subject  is  not  playing  the  game.  He  has 
fallen  from  psychological  description  into  the  commonsense 
habit  of  telling  what  he  has  been  thinking  about.  He  has 
committed  the  Kundgabe  or  expression  error:  instead  of 
describing  his  thoughts,  he  is  expressing  them.  He  has  com- 
mitted the  stimulus  or  object  error,  and,  instead  of  describing 
consciousness,  is  mentioning  the  objects  with  which  con- 
sciousness was  concerned.  Confronted  with  this  objection, 
the  subject  is  apt  to  reply  that  he  has  done  his  best,  that  what 
was  present  in  his  mind  was  precisely  the  fact  or  object  men- 
tioned, and  that  if  he  is  forbidden  to  refer  to  the  object,  all 
he  can  do  is  to  hold  his  peace.  Though  this  reply  fails  to 
satisfy  the  critic,  there  is  something  to  say  in  the  subject's 
behalf.  Suppose,  for  the  sake  of  argument,  that  the  specific 
thought  content  exists:  how  would  you  propose  to  describe  it? 
You  offer  the  subject  his  choice  of  sensory  terms,  but  these 
he  rejects  as  not  fitting  the  case.  If  then  you  exclude  refer- 
ence to  objects,  you  have  nothing  further  to  offer  him  beyond 
a  few  vague  and  negative  terms,  such  as  "imageless,"  "pe- 
culiar, unanalyzable  state,"  etc.  In  fine,  the  objection  has 
force  only  on  the  assumption  that  the  state  should  be  de- 
scribed in  sensory  terms,  and  that  non-sensory  content  is 
non-existent.  It  prejudges  the  case. 

It  is  curious  that  the  presence  of  the  stimulus  error  in 
reports  of  images  is  not  treated  with  a  similar  seriousness. 
Seldom  in  the  literature  will  you  find  an  image  really  described. 
Instead  of  an  analysis  of  the  visual  picture  as  composed  of 
colors  and  shadings  in  a  certain  spatial  arrangement,  instead 
of  an  analysis  of  the  auditory  image  as  consisting  of  a  sequence 
of  elementary  sounds,  you  read  of  "a  visual  image  of  a 
Massachusetts  town,"  or  of  "an  auditory  image  of  the  ex- 
perimenter saying  'subordinate  concept."  If  it  is  com- 
mitting the  stimulus  error  to  report  a  "thought  of"  such  and 
such  an  object,  it  is  equally  committing  it  to  report  an 
"image  of"  the  object.  A  strictly  descriptive  regimen  would 
require  the  subject,  one  would  think,  to  exclude  all  reference 
to  the  object  in  the  one  case  as  in  the  other. 

Yet  consider  the  situation  of  an  observer  who  is  forbidden 


8  R.  S.   WOOD  WORTH 

to  refer  to  the  object  in  describing  his  images.  He  would 
have  to  confine  his  report  to  such  statements  as  "a  bright, 
somewhat  variegated  spot  against  a  dark  ground,"  omitting 
to  state  that  this  was  an  image  of  his  friend's  face.  Yet,  if 
the  image,  whether  faint  or  vivid,  schematic  or  detailed,  was 
for  him,  at  the  moment,  an  image  of  his  friend's  face,  can  he 
properly  describe  the  consciousness  of  that  moment  without 
reference  to  his  friend?  No  question  of  the  logic  of  meaning 
is  here  involved,  but  a  mere  question  of  fact:  Was  or  was  not 
a  reference  to  the  object  present  in  the  momentary  conscious- 
ness; and,  if  so,  can  the  state  be  described  without  reference 
to  the  object? 

The  same  question  arises  when  we  have  a  presented  object 
instead  of  an  image.  I  hear  a  noise  from  the  street  and  say, 
"There  is  a  horse  galloping  past."  This  is  a  commonsense 
reaction  which  makes  no  pretense  of  describing  consciousness. 
But  suppose  I  do  attempt  to  describe  consciousness.  It  is 
then,  perhaps,  in  order  for  me  to  tell  exactly  what  auditory 
sensations  I  had.  If  I  do  this  as  well  as  possible,  and  find 
nothing  further,  such  as  an  image,  to  report — have  I  then, 
with  my  inventory  of  auditory  sensations,  fully  accomplished 
my  task  of  describing  consciousness?  It  would  seem  not,  if 
I  actually  was  conscious  of  a  galloping  horse,  while  my  report 
makes  no  mention  of  this  object.  It  is  all  very  well  to  warn 
me  of  the  stimulus  error  if  I  show  a  tendency  to  go  beyond  my 
momentary  experience  and  tell  something  about  the  horse 
which  may  be  objectively  a  fact  but  was  not  present  in  my 
mind  at  the  moment;  but  if  I  stick  closely  to  the  momentary 
experience,  reference  to  the  object  is  quite  in  order  and  in  fact 
indispensable;  for,  as  a  matter  of  fact,  reference  to  the  object 
was  probably  the  most  prominent  part  of  the  experience.  This 
is  equally  true  in  the  case  of  an  image,  and  I  must  conclude 
that  an  observer  is  perfectly  justified  in  reporting  an  "image 
of  his  friend's  face,"  and  that  he  could  not  omit  this  reference 
to  the  object  without  badly  mutilating  the  experience.  If  so, 
the  observer  who  reports  the  "thought  of  such  and  such 
an  object"  is  equally  within  his  rights.  He  may  have  omitted 
something  which  a  complete  description  should  include,  but 


A  REVISION  OF  IMAGELESS   THOUGHT  9 

he  has,  in  all  probability,  reported  the  most  prominent  datum 
of  his  momentary  consciousness. 

One  further 'important  objection  to  the  doctrine  of  image- 
less  thought  is  contained  in  the  teaching  of  such  men  as 
James,  Ebbinghaus  and  Dewey.  In  speaking  of  non-sensory 
content,  we  have  neglected  to  define  sensation,  or,  worse  yet, 
we  have,  according  to  these  authors,  fallen  into  the  error  of 
excluding  relations,  forms,  patterns,  meanings  from  our 
concept  of  sensation,  and  then  being  badly  put  to  it  to  explain 
how  they  get  into  perception  and  thought.  It  is  impossible, 
we  are  told,  to  draw  a  line  in  sense  perception  between  what  is 
sensation  and  what  is  perception;  and  there  is  therefore  no 
excuse  for  speaking  of  non-sensory  content  in  sense  percep- 
tion, nor  for  speaking  of  such  content  as  present  in  thinking, 
unless  we  are  ready  to  make  the  improbable  assertion  that 
positive  content  is  vouchsafed  us  when  withdrawn  from  the 
world  of  sense  that  can  never  be  experienced  in  the  presence 
of  physical  objects. 

Instead  of  attempting  to  meet  this-  objection  directly, 
I  propose  to  go  on  with  a  positive  interpretation  of  imageless 
thought,  in  the  hope  that  it  may  avoid  the  difficulty,  and 
ultimately  find  a  legitimate  ground  for  the  distinction  between 
sensory  and  non-sensory. 

To  reach  a  positive  interpretation  that  shall  have  any 
real  significance,  it  is  essential  to  turn  away  from  the  isolated 
fact  thus  far  considered,  and  seek  other  facts  which  may  be 
brought  into  relation  to  it.  A  hint  as  to  the  most  profitable 
direction  in  which  to  seek  for  related  facts  is  afforded  by  the 
following  consideration.  Thought  deals  largely  with  data 
derived  from  past  experience.  New  ideas  may  certainly 
be  generated  in  the  process  of  thinking,  but  in  very  large 
measure  the  content  of  thought  is  provided  by  memory;  and 
it  is  usually  this  memory  content  which  appears  in  the  image- 
less  form.  It  may  then  be  profitable  to  bring  our  rather 
extensive  knowledge  of  memory  into  relation  with  the  phe- 
nomenon of  imageless  thought;  and  it  is  in  that  direction  that 
I  propose  to  search. 

On  examining  the  way  in  which  recalled  facts  present 


io  R.  S.  WOODWORTH 

themselves,  we  are  at  once  struck  by  something  that  broadens 
the  outlook  considerably.  It  is  not  only  in  thinking,  properly 
so  called,  that  facts  come  to  mind  without  images,  but  in 
the  most  commonplace  acts  of  memory.  I  recall,  without 
visual,  verbal  or  other  observable  images,  what  I  have  in  my 
pockets,  where  I  left  my  umbrella,  whether  my  neighbor  is  at 
home  today.  This  imageless  recall  is  with  some  individuals 
quite  the  rule.  The  facts  are  clearly  enough  present  in  mind, 
but  if  there  be  any  image  it  is  so  excessively  dim  as  to  elude 
detection.  Such  imageless  recall  is  indicated  though  perhaps 
not  fully  demonstrated  by  some  of  Galton's  results;  and  Miss 
Martin  has  recently1  given  a  clear  demonstration  of  the 
existence  of  memory  content  that  is  "unanschaulich." 

In  imageless  thought,  then,  the  imagelessness  has  nothing 
particular  to  do  with  the  thinking  process;  and  we  are  per- 
mitted to  drop,  with  some  relief,  the  elevated  tone  that  has 
sometimes  seemed  appropriate  to  the  topic.  Thought  is 
imageless  because  its  data  are  recalled  in  an  imageless  form, 
and  not  because  it  does  not  thrive  in  a  sensory  atmosphere. 
Much  effective  thinking  occurs  in  the  physical  presence  of 
its  object.  The  use  of  the  word  " thoughts"  to  denote  non- 
sensory  content  is  unfortunate,  for  the  words  "thought"  and 
"thinking"  customarily  denote  a  certain  mental  function  or 
group  of  functions,  and  cannot  easily  be  restricted  to  any 
particular  sort  of  content.  The  best  word  would  be  one  that 
suggested  recall  rather  than  thinking;  but  I  am  not  at  present 
prepared  to  suggest  a  suitable  nomenclature.2 

1  Ze itschrift  f.  PsychoL,  1912,  65,  417-490. 

2  Unless  the  following  suggestion  can  be  seriously  entertained.     It  has  long  ap- 
peared to  me  that  we  psychologists  were  on  the  wrong  track  in  our  selection  of  technical 
terms.     Our  custom  is  to  choose  some  term  of  common  usage  that  may  convey  to  the 
uninitiated  a  suggestion  of  the  technical  meaning  newly  attached  to  it.     The  trouble 
is  that  the  untechnical  usage  continues  alongside  of  the  technical  and  tends  to  cause 
confusion;  until  finally  psychologists  are  driven  to  exclude  the  untechnical  use  from 
their  discourse,  and  thus  lose  a  very  convenient  tool  of  expression.     It  is  nothing  less 
than  a  scandal,  for  example,  that  the  word  "feeling"  should  have  been  so  refined 
in  usage  that  the  psychologist  can  no  longer  speak  of  a  "feeling  of  hesitation,"  and 
scarcely  of  a  "feeling  of  familiarity,"  without  an  apology  and  the  dread  of  being  mis- 
understood by  his  colleagues.    The  older  sciences,  with  their  greater  need  for  an 
extensive  technical  vocabulary,  have  gone  to  work  in  quite  a  different  way.    They 
either  take  unfamiliar  Greek  and  Latin  words  and  derivatives,  or  they  set  apart 


A  REVISION  OF  IM AGELESS   THOUGHT  n 

What,  then,  is  it,  in  general,  that  is  recalled?  An  old 
standard  answer  is  that  we  recall  our  past  experiences.  Ob- 
jection has  several  times  been  raised  to  this  answer  within 
the  last  two  decades;  but  the  following  line  of  criticism  is 
perhaps  new.  In  experiments  on  testimony,  or  on  "incidental 
memory,"  the  subject  is  found  to  be  incapable  of  recalling 
much  that  has  been  before  his  eyes,  and  even  within  the 
general  scope  of  his  attention.  If  he  could  call  back  his 
original  experience,  it  would  seem  that  he  could  give  the 
testimony  required  of  him.  A  specially  instructive  experi- 
ment, for  our  present  purpose,  is  that  of  Thorndike,1  who 
asked  his  subjects  to  call  up  an  image  of  a  certain  scene,  as 
of  the  front  of  a  familiar  building,  and  then,  after  they  had 
estimated  the  vividness  of  their  images,  asked  them  specific 
questions,  as  to  the  number  of  pillars  in  the  facade  and  similar 
details.  He  found  a  marked  inability  to  answer  the  specific 
questions,  even  on  the  part  of  individuals  with  very  lifelike 
images;  and,  in  fact,  there  was  little  or  no  correspondence 
between  vividness  of  image  and  correctness  of  report  on 
details.  I  have  frequently  repeated  this  experiment  with  the 
same  results.  I  have  never  found  an  individual  able  to  read 
off  the  number  of  pillars  from  his  image.  Only  those  could 
tell  the  number  who  had  at  some  time  counted  them;  and 
other  subjects  protested  that  it  was  not  fair  to  expect  them  to 
find  the  number  of  pillars  in  the  image,  when  they  had  never 
counted  them  in  the  original.  All  this  seemed  highly  sug- 
gestive. It  suggested  that  only  that  was  recalled  which  had 
been  noted  in  the  original  experience;  and  that  even  vivid 

some  proper  name  to  serve  the  special  purpose.  Thus  they  have  their  watts  and 
volts  and  ohms  and  amperes,  terms  regarding  the  meaning  of  which  no  one  need 
ever  be  in  doubt.  Such  terms  are  much  better  than  "thoughts,"  or  than  "Bewusst- 
seinslagen,"  with  its  doubtful  translation  of  "conscious  attitudes."  I  would  propose, 
accordingly,  to  follow  the  lead  of  physics  and  chemistry;  and  since  Bewusstseinslagen 
were  first  reported  and  defined  in  the  work  of  Marbe  and  his  associates,  I  would  suggest 
calling  them  "marbs,"  the  term  to  be  defined  for  all  time  by  reference  to  the  original 
description  by  Marbe.  Similarly,  since  the  "thoughts"  were  gradually  brought  to 
light  by  the  school  of  which  Kiilpe  was  the  guiding  spirit,  I  would  suggest  calling  them 
<*kulps,"  defining  this  term  similarly  by  reference  to  the  original  works.  These  terms 
are  certainly  beautifully  compact  and  euphonious,  and  those  who  can  bring  themselves 
to  use  them  will  find  them  very  convenient. 
1  /.  of  Philos.,  1907,  4,  324. 


12  R.  S.   WOODWORTH 

images,  described  as  being  fully  equal  to  the  actual  experience, 
were  in  fact  something  quite  different. 

I  was  thus  prompted  to  undertake  an  examination  of 
images  and  other  content  of  recall,  in  order  to  see  how  far 
they  could  be  described  as  revivals  of  past  experiences,  and 
how  far  they  consisted  of  facts  noted  in  the  past.  I  set 
myself  to  recall  events  from  my  past  life,  and  in  other  cases 
to  recall  persons,  buildings,  towns,  and  such  specific  facts  as 
the  exact  colors  of  postage  stamps,  the  quality  of  a  friend's 
voice,  the  shapes,  tastes,  odors,  etc.,  of  a  great  variety  of 
objects.  What  I  got  was  sometimes  to  be  called  an  image  and 
sometimes  not;  but  in  all  cases,  with  a  few  doubtful  exceptions, 
it  consisted  of  facts  previously  noted.  When  I  say  "facts," 
I  do  not  mean  verbal  statements  of  facts,  but  a  direct  con- 
sciousness of  some  thing,  quality,  relation,  action — of  some- 
thing which  I  had  observed  in  the  original  experience.  I  did 
not  get  back  experiences  as  concrete  totals,  but  only  facts 
which  I  had  discriminated  out  of  those  totals.  In  the  original 
experiences,  those  facts  had  had  a  concrete  setting  or  back- 
ground; but  this  setting  was  not  recalled.  The  facts  were 
recalled  in  isolation. 

Often,  indeed,  a  rudimentary  setting  was  present,  con- 
sisting of  either  a  personal  reference,  or  a  spatial  reference, 
or  both.  By  "personal  reference"  is  meant  that  the  fact 
was  recalled  as  my  own  experience,  or  that  the  relation  of  the 
fact  to  me,  or  my  attitude  to  it,  was  recalled  along  with  the 
fact.  By  "spatial  reference"  is  meant  that  an  object  was 
recalled  as  being  to  the  right  or  left,  or  in  a  certain  town,  or  in 
a  certain  direction  from  my  position  at  the  time  of  recall. 
Spatial  reference  was  more  frequently  present  than  personal. 
Neither  was  universally  present;  and,  aside  from  them,  no 
setting  was  recalled.  It  frequently  happened  that  several 
facts  derived  from  the  same  experience,  or  from  different 
experiences,  were  recalled  almost  or  quite  simultaneously,  so 
that  the  recall  was  richer  than  would  be  suggested  by  the 
expression,  "isolated  fact."  Nevertheless  all  of  these  facts 
had  been  previously  noted,  and  they  did  not  bring  their  con- 
crete setting  back  with  them. 


A  REVISION  OF  IM AGELESS  THOUGHT  13 

As  an  example  of  my  results,  I  will  cite  the  recall  of  a 
colleague  speaking  in  faculty  meeting.  What  I  got  was  a 
certain  quality  of  voice  and  precise  manner  of  enunciating, 
rather  different  from  the  conversational  tone  of  this  individual. 
There  were  no  words  nor  particular  vowel  or  consonantal 
sounds  present  in  recall,  but  simply  the  quality  of  the  voice 
and  enunciation.  I  got  also  the  fact  that  the  speaker  was 
speaking  as  chairman  of  a  committee,  and  something  of  the 
rather  critical  attitude  of  the  faculty  towards  him,  these  facts 
being  recalled  in  the  "imageless"  way.  Besides,  I  got  a 
spatial  reference,  in  that  the  speaker  was  located  in  a  certain 
position  with  respect  to  my  position  in  the  meeting;  and  a 
vague  personal  reference  amounting  to  an  attitude  of  support 
or  well-wishing.  Beyond  this,  nothing.  No  visual  back- 
ground of  faces  or  furniture,  no  auditory  background  of 
words  spoken,  no  somesthetic  background  of  myself  sitting. 

Among  the  facts  thus  recalled  in  relative  isolation  and 
without  concrete  setting  were  the  following: 

Of  persons:  shape  of  head  or  of  nose,  breadth  of  face,  color 
of  eye,  curliness  of  hair,  blotchiness  of  complexion,  facial 
expression,  tone  of  voice,  trick  of  gesture,  " smoothness"  of 
manner,  social  position,  ability,  industry,  relation  to  myself, 
as  being  friendly  or  unfriendly,  a  superior  or  dependent, 
agreeable,  a  bore,  etc.,  or  as  having  been  seen  recently  or  long 
ago. 

Of  buildings:  location,  size,  color,  material,  architectural 
style. 

Of  towns:  location,  general  topography,  old  or  new  style, 
abundance  of  shade,  holiday  atmosphere,  quietness,  associ- 
ation with  certain  events. 

These  facts  run  the  gamut  from  simple  to  complex,  and 
from  sensory  to  abstrusely  relational.  They  are  so  varied  as 
to  indicate  that  any  observed  fact  can  be  recalled  in  isolation. 
Among  the  striking  instances  of  isolation  were  recall  of  the 
color  of  an  object  without  its  shape,  of  its  shape  without  its 
color,  of  its  gloss  or  shading  without  either  color  or  shape. 

The  following  interpretation  seems  scarcely  more  than  a 
restatement  of  these  results.  An  actual  situation  presents  an 


1 4  R.  S.   WOOD  WORTH 

almost  unlimited  variety  of  facts  or  features,  of  which  an 
observer  notes  a  few,  the  rest  remaining  undiscriminated  in 
the  background  and  giving  the  concrete  setting  of  the  features 
noted.  Later,  he  may  "remember"  the  situation,  but  this 
is  not  to  reinstate  it  in  its  original  multiplicity  and  continuity. 
He  recalls  the  features  which  he  observed,  or  some  of  them, 
but  not  the  great  mass  of  material  which  remained  in  the 
background.  Lacking  this  setting  or  background,  he  is  not 
in  a  position  to  make  any  fresh  observations  in  recall,  and 
thus  arises  the  weakness  of  incidental  memory. 

If  generalized  to  cover  all  cases  in  all  individuals,  this 
statement  does  indeed  go  beyond  the  evidence  at  hand. 
But  if  the  possibility  of  an  occasional  recall  of  the  concrete 
setting  is  left  open,  and  the  assertion  simply  made  that  an 
observed  fact  is  often  recalled  without  its  original  setting, 
this  conclusion,  though  modest,  is  sufficient  to  furnish  a 
positive  interpretation  of  imageless  recall. 

Were  it  true  that  a  recalled  fact  always  brought  with  it 
its  original  setting,  then,  indeed,  all  recall  would  involve 
sensory  imagery.  But  if  a  fact  is  recalled  in  isolation,  it 
depends  on  the  nature  of  the  fact  whether  the  recall  would  be 
called  imaginal  or  imageless.  If  the  fact  lay  as  it  were  on 
the  sensory  surface  of  things,  such  as  color  or  tone,  its  recall 
would  usually  be  spoken  of  as  an  image.  If  the  fact  lay  below 
the  sensory  surface,  as  the  fact  that  a  speaker  was  exagger- 
ating, or  speaking  as  chairman  of  a  committee,  an  isolated 
recall  of  this  fact  would  be  unhesitatingly  pronounced  image- 
less,  unless,  to  be  sure,  it  were  accompanied  by  a  verbal  or 
symbolic  image  derived  perhaps  from  another  source  than 
the  original  setting  of  the  fact.  The  definitely  imaginal  and 
the  definitely  imageless  are  the  extremes  of  a  series,  between 
which  lie  many  intermediate  facts  difficult  to  place  in  either 
class.  The  expression  of  a  face,  the  composition  of  a  painting, 
the  style  of  a  building  or  piece  of  music,  recalled  in  an  isolated 
way,  are  difficult  to  classify. 

If  you  set  yourself  to  discover  what  are  the  objects  of  your 
attention  in  a  sensory  experience,  you  will  usually  find  that  the 
actual  sensations  are  less  prominent  than  the  things  signified 


A  REVISION  OF  IM AGELESS   THOUGHT  *5 

by  them.  You  are  more  conscious  of  the  horse  galloping 
past  than  of  the  actual  noises  that  you  hear.  When,  there- 
fore, you  later  recall  hearing  a  horse  gallop  past,  it  is  not 
surprising  that  the  thing  signified  should  be  recalled  more 
distinctly  than  the  noises;  and  you  are  left  in  doubt  whether 
to  class  the  recall  as  an  image  or  not.  This  is  a  type  of 
numerous  cases.  An  observed  feature  of  a  situation  often 
lies  partly  "on  the  sensory  surface"  and  partly  below,  and 
the  observer  does  not  take  separate  note  of  the  sign  and  of 
the  thing  signified,  but  perceives  them  together  as  a  single 
fact.  His  recall  of  the  fact  may  then  partake  both  of  the 
sign  and  of  the  thing  signified,  though  the  sensory  flavor  is 
usually  weakened  in  recall.  The  distinction  between  im- 
aginal  and  imageless,  between  sensory  and  non-sensory,  is 
not  perfectly  sharp,  and  appears,  from  our  present  point  of 
view,  to  be  of  minor  significance,  the  main  principle  being 
the  isolated  recall  of  observed  facts. 

I  ought  really  to  rest  content  with  the  conservative  state- 
ments that  precede,  and  leave  imageless  recall  as  an  incident 
to  the  occasional,  or  frequent,  recall  in  isolation  of  previously 
noted  facts.  But  in  the  interests  of  a  more  clean-cut  theory, 
I  am  tempted  to  more  radical  and  general  statements.  I 
propose  to  strike  out  boldly  and  formulate  a  theory,  hoping 
that,  whether  acceptable  or  not,  it  may  prove  a  stimulus  to 
thought  and  perhaps  to  experiment. 

The  first  step  towards  this  theory  is  to  generalize  the 
conclusion  derived  from  observations  already  cited,  and  to 
offer  the  hypothesis  that  all  recall  is  of  facts  previously  noted, 
freed  from  the  concrete  setting  in  which  they  occurred  when 
noted.  This  generalization  I  hold  to  be  correct  for  my  own 
case,  and,  though  the  testimony  of  many  individuals  regarding 
their  imagery  is  on  its  face  in  flat  contradiction  with  mine, 
the  objective  test  of  incidental  memory  seems  to  show  that 
there  is  something  radically  wrong  with  their  testimony. 
My  generalization  has  the  advantage  of  squaring  with  the 
facts  of  recall  as  objectively  tested,  and  the  only  difficulty  is 
to  explain  away  the  introspective  reports  of  images  "fully 
equivalent  to  actual  experience,"  and  of  "living  over  the  past 
as  if  it  were  present." 


1 6  R.  S.   WOODWORTH 

Without  pretending  to  do  full  justice  to  this  testimony,  1 
must  for  the  present  content  myself  with  a  few  remarks. 
Undoubtedly  a  person  may  become  deeply  absorbed  in  a 
remembered  experience,  because  of  its  great  interest  for  him. 
Now  his  present  interest  is  probably  the  same  as  that  which 
dominated  him  in  the  original  experience  and  led  him  to 
observe  and  react  to  certain  features.  If,  his  interest  reviving, 
he  gets  back  these  features  and  reactions,  he  has  the  essentials 
of  the  original  experience  from  his  own  point  of  view,  and 
satisfactorily  lives  it  over  again,  even  without  the  concrete 
background,  the  absence  of  which,  in  his  absorption,  he  would 
not  notice,  any  more  than  he  noted  its  presence  in  the  original 
experience. 

As  to  the  vivid  image,  said  to  be  "in  all  respects  equivalent 
to  the  actual  scene,"  we  undoubtedly  have,  in  such  a  case,  a 
revival  of  personal  attitude  and  emotional  value,  which  alone 
are  enough  to  create  a  strong  atmosphere  of  reality.  We 
must  also  recognize  that  what  an  artist  might  call  the  general 
effect  of  a  scene  is  as  much  a  fact  to  be  observed  as  any 
other.  The  features  which  can  be  analyzed  out  of  a  situation 
are  not  exclusively  details,  but  include  broad  effects  and  syn- 
theses and  anything  that  can  be  the  object  of  attention. 
If  now  you  recall  the  emotional  value  and  general  effect  of  a 
scene,  along  with  some  of  the  colors  and  other  previously 
noted  details,  you  perhaps  have  enough  to  make  you  testify, 
rashly,  that  your  image  is  in  all  respects  equivalent  to  the 
actual  scene.  A  test  of  incidental  memory  would  soon 
convince  you  that  the  "equivalence"  is  an  illusion. 

It  is  also  true  that  a  person  may  observe  a  scene  in  such 
detail  as  to  recall  a  great  number  of  its  features;  and  he  might 
express  the  wealth  of  his  recollection  by  asserting  that  he 
revived  the  entire  experience;  but,  so  long  as  what  he  recalls 
is  what  -he  previously  observed,  he  offers  no  exception  to  the 
rule  that  has  been  formulated. 

We  have  not  yet  by  any  means  exhausted  the  relevant 
information  to  be  derived  from  studies  of  memory.  Evi- 
dently we  should  be  much  helped  in  any  study  of  recall  by 
having  at  hand  a  report  of  the  process  by  which  what  is  now 


A  REVISION  OF  IM AGELESS  THOUGHT  17 

recalled  was  originally  learned.  We  should  be  helped  in 
our  present  inquiry  by  knowing  whether  "impressing  a  thing 
on  the  memory"  consists  in  simply  standing  before  the  thing 
and  letting  it  "soak  in,"  or  whether  it  consists  in  reacting  to 
the  thing  by  observing  its  characteristic  features.  It  may 
be  said  at  once  that  studies  of  memorizing  give  little  sign  of  a 
purely  receptive  attitude  on  the  part  of  the  learner,  and  much 
evidence  of  a  reactive  and  analytical  attitude.  Meumann 
emphasized  the  importance  of  the  "will  to  learn."  A  subject 
might  attentively  examine  a  list  of  nonsense  syllables,  and 
yet  make  little  progress  in  memorizing  it  unless  his  will  to 
learn  were  excited.  Now  the  "  will "  can  scarcely  be  conceived 
as  acting  without  means  or  tools;  and  its  tools  consist  of 
various  specific  reactions  to  the  matter  set  for  memorizing, 
the  reactions  varying  with  the  material  and  with  the  test  of 
memory  that  is  to  be  met.  Some  of  these  reactions  may 
properly  be  called  motor;  here  would  be  classed  the  rhythm, 
accents,  pauses  and  vocal  inflections  that  are  read  into  the 
list  by  the  learner.  But  in  large  measure  the  reactions  are 
of  the  perceptual  sort,  and  consist  in  observing  positions, 
relations,  patterns,  meanings,  in  the  matter  to  be  learned. 
The  recent  studies  of  Miiller  throw  all  these  factors  into  clear 
relief.  Memorizing  is  very  largely  a  process  of  observation, 
of  noting  those  features  of  the  material  that  will  serve  to 
hold  it  together  in  the  desired  way.  Some  of  these  features, 
such  as  patterns  and  relations  and  the  nearer-lying  meanings, 
are,  as  it  were,  found  in  the  material  itself;  while  other 
features,  the  more  far-fetched  meanings  and  associative  aids, 
are  imported  from  without;  but  this  distinction  is  only  one 
of  degree. 

The  reactions  made  in  learning,  it  should  once  more  be 
said,  are  specific,  and  adapted  not  only  to  the  material  learned 
but  also  to  the  kind  of  memory  test  that  is  anticipated.  If  the 
subject  expects  to  recite  a  list  of  words  or  syllables  throughout, 
he  observes  positions,  sequences,  patterns  and  relations  that 
will  serve  to  bind  the  whole  list  together.  If  he  expects  simply 
to  respond  to  each  of  the  odd-numbered  words  in  the  list  by 
giving  the  following  word,  as  in  the  method  of  paired  associ- 


1 8  R.  s.   WOOD  WORTH 

ates,  he  takes  each  pair  as  a  unit,  and  observes  characteristics 
of  the  pair  that  bind  it  together,  but  neglects  the  sequence  of 
pairs.  If  he  expects  to  be  called  upon  to  recognize  the  in- 
dividual words  of  the  list,  he  fixes  his  attention  on  them  singly, 
observing  in  each,  as  far  as  possible,  some  character  that  may 
serve  to  impress  it.  There  is  no  one  uniform  process  of 
learning,  and  the  will  to  learn  cannot  be  conceived  as  a  general 
force  or  agency.  What  we  find  in  memorizing  is  a  host  of 
specific  reactions,  largely  of  the  perceptual  sort. 

I  may  be  permitted  to  cite  the  results  of  a  little  experiment 
designed  to  test  this  matter.  I  read  a  list  of  twenty  pairs  of 
unrelated  words  to  a  group  of  16  adult  subjects,  instructing 
them  beforehand  to  learn  the  pairs  so  as  to  be  able  to  respond 
with  the  second  of  each  pair  when  the  first  should  be  given  as 
stimulus.  But,  after  reading  the  list  three  times,  I  told  them 
that  they  should,  if  possible,  give  also  the  first  word  of  the 
following  pair  on  getting  the  second  word  of  the  preceding 
pair  as  stimulus.  I  then  read  the  first  word  of  the  list,  waited 
5  seconds  for  the  subject  to  recall  and  write  the  second  word; 
then  read  this  second  word,  and  waited  the  same  time  for  them 
to  recall  and  write  the  the  third  word,  namely,  the  first  word  of 
the  second  pair;  and  so  on  through  the  list.  The  results  were 
most  definite:  the  second  members  of  the  pairs  were  correctly 
recalled  in  74%  of  all  the  cases,  but  the  first  members  were 
recalled  in  only  7%  of  the  cases.  The  subjects  reported 
that  this  great  difference  was  apparently  due  to  the  fact 
that  they  had  examined  each  pair  with  the  object  of  finding 
some  character  or  meaning  in  it;  whereas  they  had  neglected 
the  sequence  of  pairs  as  being  of  no  moment. 

This  result  is  instructive  in  several  ways.  It  indicates, 
first,  that  the  will  to  learn  operates  not  by  favoring  a  general 
receptive  or  memorizing  attitude,  but  by  leading  to  specific 
reactions  of  the  observational  type.  It  serves,  next,  to  fortify 
the  results  of  other  experiments  on  "incidental  memory." 
Here  the  objection  cannot  be  raised  that  the  incidental  matter 
that  is  not  recalled  was  never  attended  to;  for  the  first  words 
of  the  pairs  were  attended  to  as  well  as  the  second.  The 
experiment  also  shows  the  unsatisfactory  character  of  Ward's 


A  REVISION  OF  IMAGELESS  THOUGHT  19 

conception  of  the  process  of  learning.  He  has  said  that 
associations  are  formed  by  the  movement  of  attention  from 
one  to  the  other  of  the  terms  associated.  But  here  attention 
moved  from  the  first  to  the  second  member  of  a  pair,  and 
thence  to  the  first  member  of  the  next  pair;  yet  the  first  move- 
ment seems  to  have  established  a  strong  association,  and  the 
second,  comparatively  speaking,  none.  Evidently  something 
much  more  specific  than  a  mere  movement  of  attention  has 
been  in  play.  The  members  of  a  pair  are  associated  by  the 
sequence,  connection  or  meaning  that  is  found  in  the  pair. 
Finally,  this  experiment  serves  to  strengthen  doubts  that  have 
often  been  raised,  especially  by  the  work  on  incidental 
memory,  regarding  the  adequacy  of  contiguity  in  experience 
as  an  associating  force.  Here  the  contiguity  between  the 
members  of  a  pair  was  scarcely  greater,  in  matter  of  time, 
than  that  between  successive  pairs;  yet  the  association  within 
pairs  was  strong,  and  that  between  successive  pairs  almost 
negligible.  Since  the  associations  within  pairs  gave  10  times 
as  good  a  score  as  those  between  pairs,  we  may  perhaps  say 
that  mere  contiguity  does  not  contribute  more  than  one  tenth 
of  the  whole  associating  force,  the  remaining  nine  tenths  being 
contributed  by  the  noting  of  suitable  features  in  the  material. 
Even  the  small  fraction  thus  left  to  contiguity  does  not  neces- 
sarily belong  to  it;  for  it  is  not  improbable  that  the  sequence 
and  relation  of  successive  pairs  were  sometimes  observed. 
In  fact,  of  the  few  correct  recalls  of  first  members,  practically 
all  occurred  at  the  beginning  or  end  of  the  list  of  twenty  pairs; 
and  it  is  quite  likely  that,  in  these  favored  positions,  attention 
was  occasionally  directed  to  such  incidental  matters  as  the 
sequence  of  pairs  or  their  positions  in  the  list.  Except  at 
the  ends  of  the  list,  the  score  for  first  members  was  only  1/85 
as  good  as  that  for  second  members  of  the  pairs;  and  this 
fraction,  rather  than  i/io,  probably  represents  the  proportion 
of  the  total  associative  force  that  should  be  assigned  to  mere 
contiguity;  though  even  this  is  a  doubtful  concession. 

It  may  be  considered  superfluous  bravery  in  me  to  chal- 
lenge the  doctrine  of  association  by  contiguity,  in  addition 
to  all  the  other  enemies  already  on  my  hands;  but,  in  reality, 


20  R.  S.  WOODWORTH 

I  have  this  doctrine  on  my  hands  at  any  rate.  For  if  contigu- 
ity in  a  momentary  experience  is  a  strong  and  sufficient  asso- 
ciative force,  then  any  item  that  is  later  recalled  will  in  turn 
recall  its  contiguous  items  and  redintegrate  the  whole  expe- 
rience or  a  large  part  of  it,  and  my  hypothesis  that  what  is 
recalled  is  observed  facts  without  their  setting  would  become 
untenable. 

Now  association  by  contiguity  has  played  a  worthy  and 
important  part  in  the  development  of  psychology,  and  its 
attempt  to  absorb  into  itself  all  other  laws  of  association  has, 
in  my  opinion,  been  a  success.  Things  become  associated 
only  when  they  are  contiguous  in  experience.  That  is  to  say 
that  contiguity  is  a  necessary  condition  of  association.  But 
is  it  a  sufficient  condition?  There  is  little  in  the  experimental 
work  on  memory  to  indicate  that  it  is  sufficient,  and  much 
to  indicate  that  it  is  not  usually  depended  on  to  accomplish 
results.  The  things  to  be  connected  must  be  together,  in 
order  to  arouse  the  reaction  connecting  them;  but,  unless 
they  arouse  some  such  reaction,  they  do  not  become  con- 
nected, except  it  be  very  weakly.  The  reaction  may  be 
described  in  a  general  way  as  a  reaction  to  the  two  things 
together;  it  is  perhaps  sometimes  a  purely  motor  reaction, 
but  most  often,  I  believe,  is  rather  to  be  called  a  perceptual 
reaction,  consisting  in  the  observation  of  some  relation 
between  the  two  things,  or  some  character  of  the  whole 
composed  of  the  two  taken  together.  In  any  case,  the 
reaction  is  specific;  and  it  is  this  specific  reaction,  rather  than 
any  general  factor  like  contiguity,  or  the  movement  of  at- 
tention, or  the  will  to  learn,  that  does  the  work  of  association. 
To  judge  from  the  memory  experiments,  then,  what  is  recalled 
is  what  has  been  noted — not  past  experiences  in  their  totality, 
but  definite  reactions  which  occurred  in  those  experiences. 

This  conclusion  is  perhaps  even  more  clearly  indicated  by 
experiments  in  the  learning  of  nonsense  drawings  than  in  the 
more  usual  work  with  linguistic  materials.  An  instructive 
experiment  is  that  of  Judd  and  Cowling,1  who  exposed  a 
rather  simple  drawing  for  successive  periods  of  10  seconds, 

l"  Studies  in  Perceptual  Development,"  PSYCHOL.  REV.  MONOGRAPH  34,  1907, 
349-369. 


A  REVISION  OF  IM AGELESS  THOUGHT  2* 

requiring  the  subject  to  reproduce  it  as  well  as  possible  after 
each  exposure.  '  The  results,  both  objective  and  introspective, 
showed  that  the  subject  usually  got  first  the  general  character 
and  shape  of  the  figure,  and,  continuing  his  analysis,  noted 
one  fact  after  another,  until  a  sufficient  number  of  facts  was 
known  to  make  a  satisfactory  reproduction  possible.  There 
was  no  evidence  of  an  inner  reproduction  of  the  entire  sensory 
experience,  from  which  the  subject  might  read  off  such  in- 
formation as  he  required.  In  a  somewhat  similar  experiment, 
T.  V.  Moore1  called  for  the  learning  of  a  series  of  simple 
drawings.  He  supposed  at  the  outset  that  a  group  of  figures 
would  be  memorized  by  visual  imagery,  but  experience  taught 
him  that  there  was  another  factor  that  was  a  powerful  aid 
to  memory.  This  was  "a  more  or  less  complete  analysis  of 
the  figures,  an  analysis  which  it  is  utterly  unneccessary  for 
the  subject  to  put  into  words."  It  consisted  in  noting  the 
parts  and  composition  of  the  figures  and  their  resemblances 
to  familiar  objects.  He  then  undertook  to  compare  the 
efficiency  of  memorizing  by  visualization  with  analysis 
excluded,  and  by  analysis  without  visualization;  and  found  a 
uniform  superiority  of  the  analytic  method  over  the  visual- 
izing. But  he  also  found  that  it  was  impossible  to  exclude 
analysis  altogether.  "  Associations  crop  up  spontaneously," 
he  writes,  "and  one  simply  cannot  exclude  all  analysis  of  the 
figure.  ...  It  is  much  easier  to  memorize  by  analysis  to  the 
exclusion  of  imagery  than  vice  versa"  He  believed,  however, 
that  learning  by  visualization,  i.  e.,  by  forming  an  image 
which  should  be  a  "more  or  less  perfect  replica"  of  the  visual 
sensation,  was  a  real  process.  Under  the  circumstances,  it 
was  evidently  impossible  for  him  to  prove  this;  for  if  analysis 
occurred  spontaneously — and  one  has  only  to  look  at  a 
drawing  to  realize  how  inevitable  it  is  to  note  either  details 
or  broader  characteristics — and  if  also  analysis  was  a  more 
powerful  memorizing  agency  than  visualization,  it  remains 
possible  that  all  the  learning  was  accomplished  by  analysis. 
The  reality  of  the  strictly  visualizing  or  photographic  process 
of  learning  is,  I  believe,  still  open  to  doubt.  It  is  certainly 

1  "The  Process  of  Abstraction,"  Univ.  of  California  Publications  in  Psychology, 
1910,  i,  139-153. 


22  R.  S.  WOODWORTH 

impossible  to  avoid  perceptual  reactions,  and  to  assume  the 
purely  receptive  attitude  of  a  photographic  plate. 

Miss  FernakTs  data  on  the  memorization  of  pictures1 
show  that  even  good  visualizers  depend  largely,  at  least,  on 
specific  observations  of  the  features  which  were  later  re- 
membered; and  her  results  on  the  recitation  of  letter-squares 
in  changed  orders2  showed  that  even  the  best  visualizers  among 
her  subjects  were  unable  to  do  what  it  had  been  supposed  was 
the  prerogative  of  a  visualizer  to  do,  namely,  "see  the  whole 
set  of  letters  at  once  and  simply  read  them  off"  in  the  changed 
order.  She  does  not  doubt  the  existence  of  persons  able  to 
accomplish  this  feat,  but  believes  that  they  must  be  rare. 
This  matter  of  visualization  evidently  requires  further  study, 
but  the  possibility  is  still  open  that  even  the  best  visualizer 
does  not  carry  away  a  photograph  of  the  scene,  or  replica  of 
his  visual  sensation,  but  an  image  which  amounts  to  a  syn- 
thesis of  specific  observations,  including  observations  of 
broad  effects  and  observations  of  parts  and  their  relations. 

But  it  is  time  that  I  brought  my  theory  out  of  hiding  and 
placed  it  squarely  before  you.  I  call  it,  for  lack  of  a  better 
name,  the  mental  reaction  theory,  or  perhaps  the  perceptual 
reaction  theory.  Its  basic  idea  is  that  a  percept  is  an  inner 
reaction  to  sensation.  I  call  it  a  mental  reaction  to  dis- 
tinguish it  from  the  motor  reaction  which  several  psychologists 
have  put  forward  as  being  important  in  attention,  perception, 
association  and  the  like;  for  it  appears  to  me  that  these  sug- 
gestions, while  on  the  right  track  in  insisting  that  reaction 
is  dynamically  important,  have  mistaken  the  locus  of  the 
reaction,  and  so  are  unable  to  account  for  the  conscious 
content  that  appears  in  these  mental  activities.  This  mental 
reaction  is  not,  however,  of  the  nature  of  an  associated  sen- 
sation, appearing  as  an  image,  as  if  the  visual  sensation  of  an 
orange,  to  give  the  percept  orange,  must  reproduce  the 
sensations  of  handling  or  tasting  the  orange.  Nor,  on  the 
other  hand,  is  the  perceptual  reaction  an  emphasis  or  pattern 
or  meaning  residing  in  the  given  sensations.  It  is  something 
new,  not  present  in  the  sensations,  b  ut,  theoretically,as 

1PsYCHOL.  REV.  MONOGRAPH  58,  1912,  8iff. 
2  Ibid.,  p.  71. 


A  REVISION  OF  IMAGELESS  THOUGHT  23 

distinct  from  them  as  the  motor  reaction  is.  It  adds  new 
content  which  cannot  be  analyzed  into  elementary  sensations; 
so  that  the  sensory  elements,  which  are  often  held  to  supply, 
along  with  the  feelings,  all  the  substance  of  consciousness,  in 
reality  furnish  but  a  fraction  of  it,  and  probably  a  small 
fraction.  Each  perceptual  reaction  is  specific,  and  con- 
tributes specific  content.  In  recall,  it  is  these  perceptual 
reactions  that  are  revived,  and  not  sensation;  and  therefore 
the  content  of  recall  is  never,  in  the  strictest  sense,  sensory. 
Nevertheless,  as  was  said  before,  some  percepts  lie,  as  it 
were,  nearer  to  sensation  than  others,  so  that  the  distinction 
between  an  image  and  an  imageless  recall,  while  not  perfectly 
sharp,  is  still  legitimate. 

It  is  possible  that  this  theory  may  appear  not  so  radical 
after  all,  and  not  worth  the  expenditure  of  so  much  breath; 
for  all  will  perhaps  admit  that  a  percept  is,  in  some  sense,  a 
reaction.  It  is  therefore  my  duty  to  show  that  the  theory  is 
worse  than  it  seems,  and  this  I  shall  attempt  to  do  in  the  case 
of  patterns  or  Gestaltqualitaten.  It  has  long  been  known 
that  the  same  pattern  (for  example,  a  melody)  can  sometimes 
be  found  in  different  sensory  complexes,  and  it  is  also  true 
that  different  patterns  can  be  found  in  the  same  sensory 
complex,  as  in  the  case  of  the  dot  figure.  A  rather  difficult 
problem  is  thus  raised,  for  one  would  think  that  the  compound 
would  be  determined  by  the  elements.  But  the  real  crux  of 
the  difficulty  is  to  get  some  conception  of  a  pattern  or  of  a 
compound,  to  show  what  is  meant  by  the  togetherness  or 
grouping  of  the  elements.  There  are  three  theories  that 
attempt  to  solve  this  puzzle,  that  of  synthesis,  that  of  systasis 
or  mere  togetherness,  and  that  of  synergy,  which  is  none  other 
than  the  mental  reaction  theory.  The  synthesis  theory  brings 
in  the  subject  or  ego  to  put  the  elements  together;  the  systasis 
theory  rejects  this  deus  ex  machina,  and  says  that  the  ele- 
ments merely  are  together,  or  get  together  and  so  constitute 
the  compound  or  pattern;  the  synergy  theory  holds  that  the 
elements  act  together,  as  stimuli,  to  arouse  a  further  reaction 
which  is  the  pattern.  The  synthetic  theory  occupies  a  weak 
position,  since,  unless  the  systatic  theory  succeeds  in  showing 


24  R.  S.  WOOD  WORTH 

what  is  meant  by  the  elements  being  together,  there  is  no 
advantage  in  saying  that  something  puts  them  so. 

Now  it  is  difficult  to  understand  what  can  be  meant  by  the 
elements  being  together  or  getting  together  so  as  to  produce 
the  group  and  pattern.  If  the  group  included  the  whole 
momentary  content  of  consciousness,  we  could  say  that 
being  together  meant  simply  being  simultaneously  present, 
and  speak  of  the  pattern  as  a  character  of  the  whole  conscious 
moment.  But  the  group  does  not  include  the  whole  of  con- 
sciousness, but — as  in  the  case  of  three  dots  among  a  larger 
number,  seen  for  an  instant  as  a  triangle — may  occupy  but  a 
small  part  of  the  conscious  field.  The  pattern  is  not  the 
pattern  of  consciousness,  but  a  pattern  within  consciousness. 
Nor  will  it  help  matters  much  to  substitute  for  consciousness 
the  field  of  attention;  for  the  extent  of  a  group  may  be  either 
greater  or  smaller  than  that  of  this  field;  and,  besides,  a 
familiar  pattern,  such  as  a  melody  or  arrangement  of  lines  or 
dots,  may  come  to  consciousness  quite  outside  the  field  of 
attention.  Apperception,  then,  in  the  Wundtian  sense,  does 
not  explain  groups  and  patterns  nor  give  them  any  intelligible 
meaning.  But  if  we  lay  aside  apperception  and  try  to  describe 
groups  and  patterns  in  terms  of  their  constituent  elements, 
we  are  in  no  better  case.  What  is  it  that  changes  when  the 
pattern  changes,  the  elements  remaining  constant  in  quality, 
intensity  and  spatial  position?  This  question  is  as  serious 
for  the  synthetic  theory  as  for  the  systatic.  The  synergy 
theory  cuts  the  Gordian  knot  by  admitting  at  once  that  there 
is  no  change  in  the  elements.  In  fact,  there  is  no  real  grouping 
or  pattern  of  the  elements;  they  neither  get  together  nor  are 
put  together  by  some  higher  agency;  but  some  of  them  simply 
act  together,  as  a  complex  of  stimuli,  to  arouse  a  perceptual 
reaction  which  constitutes  the  grouping  and  pattern.  The 
pattern  is  numerically  distinct  from  the  elements,  as  a  motor 
reaction  is  distinct  from  the  complex  of  stimuli  that  arouses 
it.  What  pattern  shall  be  aroused  at  any  moment  depends 
on  the  readiness  of  different  perceptual  reactions  to  be  aroused, 
and  thus  on  such  factors  as  frequency  and  recency  of  past 
exercise,  fatigue  and  present  interest  and  control.  In  short, 


A  REVISION  OF  IMAGELESS  THOUGHT  25 

the  synergy  theory  proposes  to  extend  to  patterns,  and  to  all 
percepts,  the  same  explanation  that  is  accepted  for  such  ad- 
mittedly mental  reactions  as  the  sequence  of  one  idea  after 
another.  No  one  doubts  that  one  idea  may  represent  a 
stimulus  for  the  arousal  of  another  idea,  nor  denies  that  the 
aroused  idea  is  numerically  distinct  from  the  stimulus  idea 
and  adds  new  content  to  it.  It  is  the  same  with  sensation 
and  perception,  except  that  the  reaction  is  usually  very 
prompt  and  the  perceptual  content  intimately  fused  with  the 
sensational.  The  fusion  is  so  complete  that  the  pattern 
seems  to  lie  right  in  or  among  the  dots,  as  the  galloping  horse 
of  an  earlier  illustration  seemed  to  be  actually  heard  in  the 
series  of  noises. 

But  now,  finally,  I  suspect  that  the  party,  which  allowed 
me  to  proceed  some  time  ago  without  coming  to  terms  with 
their  demand  for  a  definition  of  sensation,  will  no  longer  be 
restrained.  They  will  insist  on  taking  the  floor  and  address- 
ing you  as  follows:  "The  speaker  is  certainly  right  in  calling 
a  percept  a  reaction;  that  is  too  obvious  a  fact  to  need  dis- 
cussion. But  we  ask,  A  reaction  to  what?  And  our  answer 
is,  To  the  physical  stimulus.  This  ' sensation'  that  the 
speaker  has  interpolated  between  the  physical  stimulus  and 
the  percept  is  pure  gratuitous  assumption.  There  is  no 
warrant  for  it  in  introspection,  for  he  himself  admits  that  the 
sensation  and  the  percept  content. are  intimately  fused.  We 
regret  that  he  has  fallen  into  this  obsolescent  way  of  speaking, 
and  would  suggest  that,  in  reviewing  his  remarks,  you  use  the 
blue  pencil  of  the  censor  wherever  the  word  'sensation' 


occurs." 


This  objection  is  almost  too  serious  to  be  dealt  with  in 
brief.  I  should  freely  admit  that  sensation  and  percept 
cannot  be  distinguished  by  direct  introspection.  Yet  there 
are  introspective  facts  that  make  the  distinction  appear 
legitimate.  When  we  hear  the  galloping  horse,  we  are  not 
only  aware  of  the  horse,  but  we  are  able  to  state  that  we  hear 
him.  It  is  not  quite  correct  to  say  that  we  get  only  the 
meaning,  for  we  know  also  the  sense  by  which  we  get  the 
meaning.  So,  again,  when  we  have  changing  percepts  of  the 


26  R.  S.  WOODWORTH 

same  stimulus,  as  in  the  case  of  the  dot  figure,  the  change  of 
pattern  does  not  amount  to  a  complete  change  of  the  figure, 
but  there  is  a  constant  substratum  underlying  the  changes; 
and  it  seems  appropriate  to  speak  of  this  as  sensation.  In 
recall,  even  the  best  images  lack  something  when  compared 
with  actual  sensory  experience.  They  lack  body  and  in- 
cisiveness;  and  it  appears  probable  that  this  lack  is  nothing 
more  nor  less  than  a  lack  of  sensation,  or,  in  other  words,  that 
the  real  sensory  process  is  not  resuscitated  in  the  image. 

But  the  concept  of  sensation  might  never  have  arisen  in  a 
purely  introspective  psychology.  At  bottom  it  is  a  physio- 
logical or  psychophysical  concept.  Sensation  is  that  con- 
scious content  which  is  in  closest  relation  to  the  physical 
stimulus.  It  is  the  primary  response  to  the  stimulus,  and 
may  be  followed  by  secondary  responses.  Neurology  gives 
good  ground  for  such  a  distinction,  in  tracing  the  sensory 
nerves  to  certain  limited  areas  of  the  cortex,  and  finding  the 
rest  of  the  cortex  to  be  only  indirectly  connected  with  the 
sense  organs.  Destruction  of  the  cortical  receiving  station 
for  any  sense  abolishes  all  conscious  use  of  that  sense,  while 
destruction  of  neighboring  areas,  without  making  a  person 
blind,  for  example,  abolishes  his  power  of  reading,  or  his 
power  of  recognizing  seen  objects,  or  his  power  of  orienting 
himself  in  visual  space.  Such  perceptions  are  apparently 
secondary  reactions,  while  the  primary  reaction,  correspond- 
ing to  the  activity  of  the  receiving  station,  is  precisely  that 
which  distinguishes  a  person  who  is  word-blind  and  object 
blind,  from  one  who  is  totally  blind.  Here  is  a  person  who 
sees  without  perceiving,  and  here  is  one  who  does  not  see  at 
all.  The  difference  I  would  like  to  call  sensation.  Sensation, 
accordingly,  would  be  the  consciousness  attending  the  activity 
of  the  sensory  receiving  stations  of  the  brain,  while  percept- 
content  would  be  the  consciousness  attending  the  activity  of 
neighboring  areas.  Besides  these  secondary  reactions,  there 
are  undoubtedly  tertiary  and  further  reactions,  less  and  less 
directly  connected  with  the  incoming  sensory  impulses.  They 
need  not  have  a  sharply  limited  localization  in  the  cortex, 
yet  they  must  be  neurologically  distinct,  and  it  may  well  be 


A  REVISION  OF  IMAGELESS  THOUGHT  27 

that  every  distinct  cerebral  reaction  is  attended  by  its 
peculiar  conscious  content.  I  know  of  no  reason  in  neurology 
or  psychology  for  supposing  that  the  elements  of  conscious 
content  are  contributed  solely  by  the  sensory  receiving  centers. 

According  to  this  theory,  the  sensation  aroused  by  a 
physical  stimulus  must  precede  the  secondary  or  perceptual 
reaction;  but  the  interval  need  not  be  supposed  to  exceed  a 
hundredth  of  a  second,  and  could  not  be  introspectively 
detected.  The  fusion  of  the  primary  and  secondary  reactions 
in  consciousness  is  a  fact  which  I  cannot  attempt  to  explain, 
since  fusion  is  one  of  the  fundamental  peculiarities  of  con- 
sciousness as  contrasted  with  its  cerebral  correlates.  But 
I  may  perhaps  make  the  whole  conception  a  little  more 
tangible  by  reverting  to  the  similitude  of  photography. 

A  certain  photographer  found  himself  without  sensitive 
plates,  though  with  his  camera,  in  the  presence  of  a  scene 
which  he  much  desired  to  preserve.  He  therefore  focused  on 
the  ground  glass  at  the  back  of  his  instrument,  and,  stretching 
transparent  paper  over  the  glass,  traced  some  of  the  outlines 
of  the  optical  image.  He  thus  created  patterns,  which  lay 
really  in  his  drawing  and  not  in  the  optical  image,  but  which 
were  blended  with  the  image  as  long  as  the  image  remained. 
He  preserved  his  tracing,  and  found  it  to  differ  from  a  photo- 
graph in  containing  only  the  facts  to  which  he  had  definitely 
reacted. 

In  this  parable,  the  optical  image  is  sensation,  which  is 
gone  forever  when  the  physical  stimulus  ceases.  The 
tracing  is  perception,  which  may  be  preserved,  though  subject 
to  decay.  But  the  fusion  of  the  two,  depending  in  the  case 
of  the  camera  on  the  presence  of  the  photographer's  eye,  is 
in  the  case  of  sensation  and  perception  more  deep-seated 
and  inexplicable.  Finally,  the  photographer  was  more 
restricted  than  is  the  process  of  perception,  since  he  could 
only  trace  outlines  and  shadings  and  perhaps  colors,  and 
could  not  commit  to  his  drawing  the  more  remote  relations 
and  meanings  which  can  be  perceived,  and,  being  later 
recalled,  furnish  the  content  of  "imageless  thought." 


A  NEW  MEASURE  OF  VISUAL  DISCRIMINATION1 

BY  KNIGHT  DUNLAP 

The  tests  on  which  this  report  is  based  were  carried  out 
in  the  Nela  Research  Laboratory  in  August  and  September 
of  1914,  as  an  adjunct  to  other  experimental  work  which  will 
be  reported  later.  The  instrument  used  was  constructed  at 
The  Johns  Hopkins  University  several  years  ago,  and  as  a 
result  of  work  with  it  since  that  time  has  been  modified  into 
the  present  form,  which  seems  good  in  principle  although 
the  mechanical  operation  may  still  be  improved. 

The  instrument  which,  for  convenience,  may  be  called  a 
duoscope,  consists  essentially  of  a  polished  crystal  of  Iceland 
spar  mounted  in  a  telescopic  brass  tube,  which  has  an  eye- 
aperture  at  one  end,  and  a  rotatable  ring  at  the  other.  The 
ring  is  rotated  by  a  worm-screw  with  a  knurled  head,  and  is 
provided  with  a  vernier  scale,  so  that  the  angle  of  rotation 
may  be  read  to  one  fifth  of  a  degree.  The  ring  is  arranged 
to  hold  a  disc  fitting  within  it,  so  that  various  forms  of  objects 
may  be  viewed  at  a  fixed  distance  from  the  eye. 

The  first  objects  tried  were  as  near  linear  as  possible:  a 
diamond-scratch  on  a  clear  glass  disc;  a  fine  glass  filament 
crossing  a  circular  aperture  in  a  metal  disc.  These  were 
tried  against  various  backgrounds,  and  were  not  satisfactory 
because  of  the  difficulty  of  securing  a  line  of  sufficient  uni- 
formity and  without  sheen.  A  narrow  slit  was  equally  un- 
satisfactory. Finally  a  rectangular  aperture  of  appreciable 
width  was  found  workable  when  used  against  a  bright  back- 
ground. 

The  Iceland  spar  crystal  gives  a  double  image  of  the  line 
(or  rectangle)  used  as  an  object,  and  the  relation  of  these 
two  images  may  be  altered  by  rotating  the  ring  which  carries 
the  line  with  it.  If  the  line  stands  exactly  in  the  refracting 

1  From  the  Nela  Research  Laboratory,  National  Lamp  Works  of  the  General 
Electric  Company. 
28 


VISUAL  DISCRIMINATION  29 

plane  of  the  crystal,  the  two  images  are  superposed  over  their 
greater  length,  their  displacement  being  longitudinal  only. 
If  the  line  be  rotated  90°  from  this  position,  the  two  images  are 
displaced  laterally  to  the  maximal  distance  possible  from  the 
prism  (1.089  mm-  witn  tne  crystal  used  in  the  present  work), 
and  if  this  distance  be  greater  than  the  width  of  the  line  (or 
rectangle)  the  two  images  are  separated. 

In  this  way,  with  a  proper  linear  object,  it  would  be  easily 
possible  to  measure  (in  terms  of  the  visual  angle)  the  displace- 
ment of  the  images  giving  just  perceptible  doubleness;  i.  e.^ 
the  minimum  visibile.  The  advantage  of  the  device  lies  in 
the  exactness  of  measurement  and  ease  of  manipulation,  with 
the  possibility  of  accommodation  for  relatively  short  or  'read- 
ing distance.'  It  is  possible  to  obtain  a  suitable  linear  object, 
but  before  I  had  found  one  I  discovered  that  observation  on  a 
rectangle  of  appreciable  width  (i.  e.,  a  relatively  wide  slit) 
is  much  easier,  and  have  therefore  adopted  such  an  object 
for  the  present.  The  fineness  of  measurement  possible  with 
this  instrument  is  indicated  by  the  fact  that  the  reading 
unit  in  the  vernier  scale  (one  fifth  of  a  degree)  corresponds,  in 
the  middle  of  the  scale  used  in  the  present  work,  to  1.6"  of 
visual  angle,  or  .0029  mm.  lateral  displacement  of  the  image. 

The  discrimination  of  doubleness  in  lines  is  of  course  a 
matter  primarily  of  difference-sensibility  for  brightness.  If 
(in  the  case  of  two  bright  lines,  or  two  images  of  a  single 
objective  bright  line),  there  is  a  perceptible  dark  stripe  down 
the  middle  of  the  combined  lines,  they  are  seen  as  two;  if 
there  is  no  dark  stripe,  as  one.  The  three  factors  involved  in 
'visual  acuity'  as  tested  by  the  linear  method1  are  therefore: 
(i)  The  physical  distribution  of  the  light-flux  on  the  retina, 
determined  by  the  'resolving  power'  of  the  eye;  (2)  The  dis- 
tribution of  energy  or  activity  in  the  physiological  image  of 
the  retina,  determined  by  the  distribution,  in  the  physical 
image,  and  by  irradiation,  etc.;  (3)  The  difference-sensibility 
for  brightness  differences.  Anything  which  changes  any  of 
these  factors,  as  a  change  in  the  lens  system,  or  in  the  irradi- 

1  In  the  case  of  determinations  by  means  of  two  points  instead  of  two  lines,  the 
situation  is  different,  and  the  histological  texture  of  the  retina  may  be  a  factor. 


30  KNIGHT  DUNLAP 

ation,  will  therefore  change  the  'acuity,'  although  the  dif- 
ference-sensibility remains  the  same.  Thus  the  practical 
usefulness  of  the  acuity-determination  depends  on  thorough 
(and  perhaps  unattainable)  control  of  the  conditions  of  ob- 
servation. These  matters  are  so  obvious  that  no  further 
discussion  is  needed  here. 

The  method  of  testing  'acuity'  by  the  double  images  of  a 
bright  rectangle  is  now  apparent.  If  the  two  images  (phys- 
ical) overlap  sufficiently,  there  is  a  brighter  line  in  the  middle 
of  the  combined  images;  if  they  are  sufficiently  separated  there 
is  a  darker  line  in  the  middle.  It  is  a  relatively  simple  matter 
to  determine  the  points  at  which  the  dark  line  and  the  bright 
line  are  just  perceptible. 

The  crystal  used  has  a  maximal  image-separation  of 
1.089  mm.,  and  the  slit  was  fixed  at  a  distance  of  approxi- 
mately 36  cm.  from  the  eye.  The  slit  was  3  cm.  long  and 
0.77  mm.  wide. 

The  most  difficult  part  of  the  adjustment  of  the  instru- 
ment is  the  determining  of  the  position  in  which  there  is  no 
lateral,  but  only  longitudinal,  displacement  of  the  images. 
This  determination  was  made  by  long  series  of  observations  of 
the  bright  line  obtained  by  moving  in  each  direction  alter- 
nately, determining  the  middle  point  from  these.  The  zero 
point  thus  obtained  is  sufficiently  exact  for  practical  purposes; 
besides,  no  more  exact  method  is  available. 

The  background  against  which  the  slit  was  viewed  was  a 
plane  disc  of  plaster  surfaced  with  magnesia,  at  a  distance  of 
97  cms.  from  the  rectangle.1  This  was  used  first  in  a  darkened 
room  and  illuminated  with  a  beam  of  light  from  a  nitrogen 
tungsten  lamp.  The  lamp  being  enclosed,  the  only  illumin- 
ation of  the  room  was  the  light  diffused  from  the  disc.  From 
the  direct  radiation  of  this  light  the  observer  was  protected 
by  a  black  screen,  through  which  the  instrument  protruded. 
The  observer  was  therefore  not  in  complete  darkness,  but  the 
illumination  in  his  direction  was  low  (1/27  to  2  c.p.).  Ten 
minutes  or  more  was  allowed  for  adaptation,  so  that  the  sub- 
ject was  really  in  a  fair  state  of  darkness  adaptation. 

1  Tests  were  made  at  other  distances,  but  as  was  expected,  the  distance  proved 
not  to  be  a  factor  in  the  results. 


VISUAL  DISCRIMINATION  31 

Subsequently  the  instrument  and  plaster  disc  were  moved 
into  a  room  we'll  lighted  with  daylight,  so  that  measurements 
were  obtained  with  daylight  adaptation. 

In  the  darkened  room  five  illuminations  of  the  plaster 
background  were  used,  giving  brightnesses  of  3,  10,  36,  82 
and  168  candles  per  square  meter. 

The  observers  were:  laboratory  helper  Mr.  Eric  Martiens- 
sen,  a  high  school  graduate;  Dr.  P.  W.  Cobb;  Dr.  H.  M. 
Johnson;  and  myself.  The  readings  on  me  were  taken  by 
Martienssen;  the  readings  on  the  other  observers  were  taken 
by  me.  Usually  twenty-five  determinations  were  made  in 
one  sitting.  Thus,  in  the  work  with  five  intensities,  five 
determinations  were  made  on  each  intensity  at  a  sitting,  with 
only  one  sitting  a  day.  Each  subject  had  preliminary  practice 
in  observing.  These  intensities  were  taken  in  a  different 
order  on  different  days.  No  practice  effect  is  noticeable  in 
the  measurements  of  any  of  the  subjects. 

The  observer  started  with  the  bright  line  plainly  visible 
and  rotated  the  slit  until  the  dark  line  was  just  visible: 
then  he  rotated  the  slit  in  the  other  direction  until  the 
bright  line  was  just  visible:  or  vice  versa.  The  observers 
found  it  easier  to  make  the  changes  rather  quickly.  Long 
looking  caused  the  difference  in  brightness  to  disappear. 

It  is  unfortunate  that  the  instrument  was  made  with  the 
crystal  fixed,  and  the  object  rotating.  It  was  so  made  because 
this  form  allows  easier  construction,  and  has  advantages  in 
adjustment  of  the  object  for  the  zero  point  which  was  de- 
sirable while  the  instrument  was  in  the  provisional  stage. 
The  next  instrument  will  be  made  with  fixed  object-holder, 
so  that  the  axis  of  the  slit  will  not  change  during  observations. 
The  rotation  of  the  axis  in  these  experiments  was  small, 
however,  and  does  not  vitiate  the  results.  In  the  table  below, 
where  the  axis  is  not  specified,  it  was  90°,  that  is  the  slit  was 
vertical  when  in  the  medial  position,  i.  e.,  in  the  position  in 
which  the  images  were  not  displaced  laterally. 

The  readings  given  in  the  table  are  the  displacements 
from  the  zero  position  in  visual  angle  computed  from  the 
averages  of  the  designated  number  of  readings  on  the  scale 


KNIGHT  DUNLAP 


of  the  instrument.  Theoretically,  the  visual  angle  should 
have  been  computed  for  each  instrument-reading,  and  then 
the  averages  of  the  computed  values  taken;  practically,  the 
computation  for  the  average  of  the  instrument-readings  is 
sufficiently  accurate.  The  mean  variations  are  not  given, 
because  I  have  so  far  not  been  able  to  discover  what  the  true 
mean  variations  are.  It  is  evident  that  the  variations  cannot 
be  referred  to  the  averages,  because  these  vary  with  the  width 
of  the  slit  employed,  regardless  of  the  uniformity  of  observa- 
tions; nor  to  the  average  of  the  range  from  dark  line  to  bright 
line,  because  there  may  be  variations  in  the  readings  which 

do  not  affect  this. 

TABLE  I 

THE  INFLUENCE  OF  BRIGHTNESS  AND  OF  ADAPTATION 

i.  Martienssen.     Left  Eye  2.  Johnson.     Right  Eye 

A.  Dark  Adaptation.    Av.  of  25  A.  Dark  Adaptation.     Av.  of  25 


Brightness 

Dk.  Line 

Br.  Line 

Range 

Dk.  Line 

Br.  Line 

Range 

3 

7'  10" 

6'  44" 

26" 

6'  59" 

6'  46" 

13' 

10 

7'  10" 

6'  49" 

21" 

/     I" 

6'  49" 

12' 

36 

7'  10" 

6'  50" 

20" 

6'  59" 

6'  49" 

10' 

82 

7'  10" 

6'  53" 

17" 

7'  oo" 

6'  49" 

II' 

168 

7'    o" 

6'  54" 

13" 

7'     2" 

6'  50" 

II' 

B.  Daylight  Adap.    Av.  of  20 


B.  Daylight  Adap.     Av.  of  20 


/ 


6'  51" 


ii' 


6'  59" 


47' 


12' 


3.  Cobb.    Right  Eye 
A.  Dark  Adap.    Av.  of  10 


4.  Dunlap.     Left  Eye 
A.  Dark  Adap.     Av.  of  25 


3 

6'  50" 

6'  27' 

23" 

7'  10" 

6'  39" 

3.1' 

10 

6'  53" 

6'  31' 

22" 

7'  n" 

6'  48" 

23' 

36 

6'  49" 

6'  26' 

23" 

7'  n" 

6'  49" 

22' 

82 
1  68 

6'  51" 
6'  52" 

6'  34' 
6'  33' 

17" 
19" 

7'  11" 
/  12" 

6'  50" 
6'  50" 

21' 

22' 

Daylight  Adap.    Av.  of  75 


7'    4" 


6'  49" 


15' 


In  the  A  parts  of  Table  I  are  given  the  general  results  of 
the  tests  with  different  brightness  of  slit  under  darkness 
adaptation,  and  in  the  B  parts,  the  corresponding  results  with 
daylight  adaptation.  Two  points  are  clear.  First,  that  in 
general  the  daylight  adaptation  gives  greater  acuity;  and 


VISUAL  DISCRIMINATION 


33 


TABLE  II 

INFLUENCE  OF  ANGLE  OF  Axis  OF  RECTANGLE 

I.  Dunlap.     Right  Eye 
A.  Daylight  Adap.     With  lens  correction.     Av.of  20 


Axis 

Dk.  Line 

Br.  Line 

Range 

Dk.  Line 

Br.  Line 

Range 

80 
90 
100 

125 
170 

f    2" 
7'     2" 

7'    2" 
7'    2" 
7'    6" 

6'  46" 

6'  45" 
6'  42" 
6'  42" 
6'  50" 

16" 
17" 

20" 
20" 

16" 

B.  Daylight  Adap.     Without  lens 
Av.  of  10 


C.  Dark  Adap.    Without  lens 
Av.  of  40 


80 

7'    4" 

6'  43" 

21" 

7'    4" 

6'  40" 

24" 

I25 

7'  10" 

6'  32" 

38" 

7'  17" 

6'  22" 

55" 

170 

7'    9" 

6'  55" 

14" 

7'  13" 

6'  46" 

27" 

2.  Martienssen.     Daylight  Adap.     Av.  of  20 
A.  Right  Eye  B.  Left  Eye 


90 

7'   9" 

6'  53" 

16" 

7'    2" 

6'  51" 

n" 

135 

7'  oo" 

6'  48" 

12" 

1  80 

Unable  to 

see  lines. 

7'    8" 

6'  54" 

14" 

67.5 

Unable  to 

see  lines. 

7'  43" 

7'  22" 

21" 

3.  Johnson.    Daylight  Adap.     Av.  of  10 
A.  Right  Eye  B.  Left  Eye 


90 

(6'  59") 

(6'  47") 

da") 

6'  59" 

6'  45" 

H" 

135 

6'  55" 

6'  46" 

9" 

6'  59" 

6'  47" 

12" 

1  80 

7'  oo" 

6'  48" 

12" 

6'  58" 

6'  45" 

13" 

67.5 

/oo" 

6'  48" 

12" 

6'  59" 

6'  46" 

H" 

second,  that  there  is  no  uniform  influence  of  brightness  within 
the  limits  of  the  conditions  obtaining. 

The  results  with  the  lowest  brightness  differ  appreciably 
from  the  results  with  the  higher  brightness,  but  this  is  due, 
in  part  at  least,  to  the  difficulty  in  judging  with  this  illumin- 
ation when  near  the  line-threshold.  This  is  a  condition 
which  must  be  distinguished  carefully  from  the  raising  of  the 
threshold  as  such,  and  was  clearly  a  factor  in  my  own  case. 
Leaving  out  the  dimmest  light,  the  influence  of  the  brightness 
is  negligible  for  Cobb,  Johnson,  and  Dunlap. 

The  change  to  daylight  adaptation  is,  however,  influential 
except  in  the  case  of  Johnson,  whose  acuity  seems  to  be 


34 


KNIGHT  DUNLAP 


exceptional.  Tests  with  the  Cobb  acuity-object  also  have 
shown  Johnson  to  have  unusual  acuity  with  darkness  adap- 
tation. It  is  quite  probable  that  the  slight  effect  of  the 
increasing  illumination  in  the  darkened  room  was  due  to  the 
lessening  of  adaptation. 

The  most  striking  result  is  the  uniform  lowness  of  the 
threshold.  The  average  range  from  dark  line  to  bright  line 
lies  for  the  most  part  near  20",  and  is  lower  in  some  cases.  In 
the  ordinary  test  object,  using  object  lines,  the  measurement 
from  fusion  to  dark  line  is  from  30"  to  60".  The  correspond- 
ing measurement  in  the  present  case  is  less  than  20";  how  much 
less  cannot  be  determined,  as  it  cannot  be  assumed  that  either 
the  points  of  geometrical  contiguity,  or  of  physical  uniformity 
of  the  images,  lie  half  way  between  the  points  at  which  the 
dark  line  and  the  bright  line  respectively  appear.  Schuster 
states  that  the  intensity  at  the  edge  of  the  geometrical  image 
of  a  uniformly  bright  surface  must  be  "half  the  intensity 
observed  at  some  distance  inside  the  edge,"  because  when 
two  surfaces  are  placed  with  edges  in  contact  a  uniformly 
illuminated  surface  is  obtained.1  Assuming  this  to  be  true 
of  the  physical  image,  it  is  not  necessarily  true  of  the  psycho- 
logical image,  as  irradiation  and  contrast  (physiological) 
effects  occur  at  the  margins  of  the  images.  The  fact  that 
both  light  line  and  dark  line  thresholds  tend  to  shift  with 
darkness  adaptation  indicates  influences  of  this  sort,  and 
we  should  accordingly  expect  the  light  line  threshold  in  gen- 
eral to  be  nearer  the  point  of  geometric  image  contiguity 
than  is  the  dark  line  threshold:  an  expectation  that  is  justified 
by  the  facts. 

Table  II  gives  the  results  of  tests  to  find  the  effects  of 
lenticular  aberrations.  My  right  eye  is  corrected  with  a  lens 
of  0.50  C.,  axis  80°,  prism  J<°  B.D.  Tests  were  accordingly 
made  on  the  eye  with  and  without  the  correcting  lens,  in  the 
astigmatic  axis  and  at  45°  on  either  side.  The  results  (II,  I, 
A,  By  and  C)  show  that  even  a  low  degree  of  astigmatism  is 
detectible  by  this  means  and  also  that  my  eye  is  slightly  under- 
corrected  by  the  lens. 

1  Schuster,  'Theory  of  Optics,'  page  151. 


VISUAL  DISCRIMINATION  35 

Tests  were  carried  out  on  both  of  Martienssen's  eyes 
(II,  2).  He  preferred  to  use  his  left  eye  in  any  sort  of  monoc- 
ular observation.  On  being  questioned  about  this  he  said 
he  had  always  used  that  eye  because  it  seemed  more  natural. 
The  tests  seem  to  indicate  a  slight  degree  of  astigmatism  in 
the  right  eye  with  less  in  the  left.  Martienssen's  eyes  had 
never  been  refracted.1  The  degree  of  astigmatism  is  not 
great,  for  with  uncorrected  eyes  requiring  from  one  to  two 
diopters  of  cylindrical  correction,  the  instrument  cannot  be 
used  at  all. 

Whether  the  instruments  and  methods  for  acuity  test 
above  described  will  be  practically  useful  remains  to  be  seen. 
In  the  matter  of  precision  and  convenience  the  apparatus 
seems  superior  to  devices  hitherto  in  use.  The  fact  that  the 
results  differ  from  those  obtained  by  means  of  the  several 
other  devices  is  immaterial.  Measurements  of  this  kind  give 
comparable  results  only  when  the  same  instruments  and 
methods  are  used.  Since  the  duoscope  method  seems  sensitive 
to  adaptation  changes,  it  may  be  possible  to  use  it  as  an  adap- 
tometer;  since  it  seems  not  sensitive  to  brightness  changes 
over  a  considerable  range,  it  may  be  a  useful  instrument  for 
practical  testing  of  eyes.  It  seems  especially  suitable  for 
detecting  slight  degrees  of  astigmatism,  and  for  detecting 
the  accuracy  with  which  lens  corrections  for  astigmatism 
are  made,  in  experimental  work  where  accurate  control  of 
the  observer's  eye  is  required. 

1  Since  the  above  was  written,  Dr.  Cobb  has  refracted  Martienssen's  eyes,  with 
the  following  results  (sine  midriatic): 

O.D.  — .     37  cyl.  axis  175° 

O.S.  — .     25  sph.  — .     37  cyl.  axis  155°. 

It  is  probable  that  the  fact  that  the  duoscope  readings  for  the  Right  Eye  are  not 
harmonious  (e.  g.,  the  inefficiency  at  67.5),  is  due  to  over  accomodation. 


AN  ELECTRO-MECHANICAL  CHRONOSCOPE 

BY  JOHN  W.  TODD 

University  of  North  Dakota 

Provided  that  certain  changes  are  made  in  its  electro- 
magnets and  that  it  is  skilfully  handled  the  most  reliable 
chronoscope  known  is  the  Hipp  chronoscope.  But  for  want 
of  skilful  handling  it  is  not  unusual  to  see  a  dust-coated  copy 
of  the  instrument  stored  away  in  a  museum  for  apparatus  that 
looks  nice  but  is  rarely  used.  Nevertheless  the  Hipp  deserves 
more  respect.  After  having  invested  in  the  costly  piece  with 
its  control-hammer  additional,  the  experimenter  should  fit  it 
for  service  by  rewinding  its  electro-magnets  with  coarser 
wire,  by  insuring  a  steady  current  with  a  good  gravity  battery 
of  12  cells,  by  discarding  the  control-hammer  and  employing 
some  type  of  gravity  chronometer  for  control  tests.1  It  is 
the  fineness  with  which  the  instrument  is  designed  to  record 
times  that  makes  it  unsatisfactory  in  inexperienced  hands  but 
that  insures  reliability  when  correctly  operated. 

Even  after  the  corrections  indicated  are  made  the  instru- 
ment must  be  constantly  watched  and  tested,  as  a  fluctuation 
of  the  current  or  a  slight  change  in  the  adjustment  of  the 
delicate  parts  of  the  apparatus  may  produce  a  chronoscope 
variation  that  will  entirely  obscure  the  variations  in  reaction 
time.  The  instrument  responds  to  all  irregularities  and  is 
never  popular  when  operated  in  a  hit  and  miss  manner.  Many 
attempts  have  been  made  to  devise  a  simpler  chronoscope 
than  the  Hipp.  The  special  aim  has  been  to  construct  one 
that  will  eliminate  the  constant  care  of  control  and  minimize 

1  The  manner  of  making  these  changes  and  the  reasons  for  them  may  be  found  in 
the  National  Academy  of  Sciences,  7,  397  ff.,  1893  (Cattell  and  Dolley).  After  cor- 
recting the  instrument  as  indicated  these  writers  found  average  variable  errors  for 
seven  series  of  ten  single  tests  of  the  chronoscope  as  follows:  0.96,  0.8,  0.42,  0.4,  0.64, 
0.64,  and  0.56".  Using  the  same  instrument  corrected  by  Cattell  the  present  writer 
in  making  several  thousand  reaction  tests  found  an  average  variation  of  the  chrono- 
scope in  control  tests  of  about  I*  ("Reaction  to  Multiple  Stimuli,"  Archives  of  Psy- 
chology, No.  25,  8,  1912). 
36 


A  NEW  CIIRONOSCOPE  37 

the  possibility  of  getting  out  of  adjustment.  The  simplest 
chronoscope  is 'one  so  designed  as  to  harness  the  force  of 
gravity  for  marking  off  units  of  space  that  may  be  given  time 
values.  This  arrangement  eliminates  delicate  clockwork 
propelling  devices  and  reduces  the  number  of  adjustable 
parts  three  fourths.  Even  after  the  chronoscope  is  reduced 
to  its  simplest  terms  three  difficult  problems  remain,  First,  to 
devise  a  reliable  chronoscope  release;  Second,  to  construct  a 
sufficiently  accurate  reaction  recorder,  and,  Third,  the 
greatest  problem  of  all,  to  put  down  a  chro  no  metric  scale  that  is 
trustworthy. 

The  chronoscope   described   in  this   article  consists  of  a 


disc  compounded  of  two  adjustable  parts  (Z)i  and  Z)2,  Fig.  i), 
which  are  two  circular  planes  of  1/16  in.  brass,  11.5  in.  in 
diameter,  with  a  concentric  semicircle  of  each  having  a  radius 
of  4.75  in.  cut  away,  leaving  in  each  case  a  marginal  area 
I  in.  in  width.  One  of  the  discs  is  constant  with  respect  to  a 
pendulum  attached  to  their  common  axis  while  the  other  is 
adjustable  to  allow  the  various  apertures  of  a  tachistoscopic 
attachment  described  later  in  this  article.  These  discs  are 
held  rigidly  together  by  a  set-screw  (S.  sc.,  Fig.  2)  and  rock 
with  the  vibrating  pendulum.  In  making  a  chronometric 
reading  with  the  electrical  arrangement  the  initial  position 
of  the  pendulum,  i.  e.,  horizontal,  is  maintained  by  the  force 


3$  JOHN  W.    TODD 

of  an  electro-magnet  (EM,  Fig.  2)  upon  the  armature  (A^ 
carried  near  the  base  of  the  pendulum  whose  socket  (P.S.)  is 
shown.  To  minimize  friction  the  shaft  carrying  the  discs 
and  the  pendulum  has  cone  bearings  (Fig.  2).  The  pendulum 
weights  are  two  cylinders  of  lead  set  in  brass.  The  gross 
relations  of  the  various  parts  of  the  apparatus  are  shown  in 
the  upper  left  corner  of  Fig.  I,  a  lateral  photograph  of  the 
apparatus. 

Fig.  2  is  a  diagram  showing  the  details  of  the  chronoscope 

P 


FIG.  2. 

arranged  for  both  mechanical  and  electrical  stimulus  key  and 
reaction  key.  The  figure  shows  the  apparatus  set  for 
mechanical  operation.  SAi  is  a  copper  shoe  held  firmly 
between  the  contact  points  of  a  stimulus  key  by  means  of  the 
insertion  of  the  inclined  surface  of  the  lever,  Z,,  and  the  re- 
siliency of  the  key  shaft,  supporting  by  means  of  a  cord  over  a 


A  NEW  CHRONOSCOPE  39 

pulley  the  armature,  A  2,  which  holds  the  pendulum  in  the 
initial  horizontal  position.  SA2  is  likewise  a  copper  shoe 
between  the  contact  points  of  the  reaction  key  held  firmly 
by  the  reagent's  finger  upon  the  button,  and  holding  the  arma- 
ture (Ai)  of  the  reaction  index  to  its  initial  position  against 
the  arm  of  the  post,  P.  The  armature,  AI,  to  which  the 
reaction  index  (7)  is  attached  moves  freely  upon  the  spindle 
bearing  the  chronoscope  disc,  and  by  means  of  a  coiled  spring 
flies  against  the  disc  when  release  is  made  and  is  carried  with 
it  allowing  the  index  pointer  to  escape  the  arm  of  the  post, 
P,  by  which  it  is  held  during  the  reaction  interval.1  When  the 
pendulum  is  in  the  initial  position  the  index  point  rests  upon 
the  zero  point  of  the  chronometric  scale.  The  index  may  be 
thrown  back  to  the  zero  point  from  any  position  on  the  scale 
by  pulling  upon  the  cord  to  which  Shz  is  fastened. 

When  the  stimulus  lever  (L)  is  suddenly  pulled  the  stim- 
ulus hammer  (S.Ss)  by  virtue  of  the  resilient  shaft  which 
carries  it  and  the  rebound  of  the  strong  coiled  spring  near  its 
fulcrum  strikes  the  solid  metallic  base  a  blow  emitting  a 
sound  which  serves  as  a  stimulus,  and  whose  intensity  is 
variable  by  means  of  set  screws.  With  the  drop  of  the  stim- 
ulus hammer  upon  the  metallic  base  and  the  emission  of  the 
sound  the  shoe  actuated  by  the  strong  spring  of  the  release 
armature  flies  from  between  the  points,  while  the  armature 
flies  back  to  position  As.  This  releases  the  pendulum  and 
carries  the  chronometric  scale  in  the  negative  direction  count- 
ing against  the  reagent  until  the  index  flies  upon  the  disc 
marking  the  close  of  the  stimulus-reaction  period. 

The  difficulty  in  attempting  to  devise  a  mechanical  chro- 
noscope is  to  give  it  versatility.  It  is  not  hard  to  provide  a 
release  that  at  the  same  time  serves  as  a  sound  stimulus,  and 
that  offers  no  resources  for  the  presentation  of  touch  and 
light  stimuli.  With  the  mechanical  device  described  above, 
however,  it  is  possible  to  give  all  three  stimuli.  This  is 
shown  by  Fig.  3,  a  diagram  of  the  three-stimulus  key.  The 
method  of  giving  the  sound  stimulus  is  described  above. 

1  This  type  of  armature  although  employed  in  a  somewhat  different  manner  was 
first  used  by  Bergstrom  in  a  pendulum  chronoscope  figured  and  described  in  the 
PSYCHOLOGICAL  REVIEW,  VII.,  1900,  438  ff. 


4o 


JOHN  W.   TODD 


When  it  is  desired  to  present  a  light  stimulus  with  the  me- 
chanical chronoscope  a  light  wooden  arm  long  enough  to 
extend  beyond  the  base  of  the  chronoscope  is  attached  to  the 
shaft  of  the  reaction  key.  This  wooden  arm  carries  a  small 
black  square  (A)  operating  as  a  shutter  to  a  I  cm.  aperture 
(Ap)  in  a  black  screen  large  enough  to  conceal  the  movements 


of  the  experimenter.  When  it  is  desired  to  use  tactual  stimuli 
the  stimulus  key,  by  means  of  the  binding  posts,  is  inserted 
into  the  primary  circuit  of  an  induction  coil  preferably  with 
condenser.  The  reaction  key  is  introduced  in  the  secondary 
circuit  in  such  manner  that  the  cathode  is  in  the  button  of 
the  key  and  the  anode  in  a  shallow  vessel  of  salt  water.  If 
the  vibrating  armature  of  the  current  interrupter  of  the 
induction  coil  is  tied  back  securely  against  its  adjustable 
contact  and  the  reacting  finger  rests  upon  the  cathode  and 
the  fingers  of  the  other  hand  rest  in  the  vessel,  a  shock  is  felt 
in  the  reacting  finger  when  the  primary  circuit  is  broken  at 
Shi.  As  the  key  is  figured  above  it  is  set  for  all  three  stimuli 
which  would  be  administered  simultaneously  with  the  sudden 
pull  toward  the  experimenter  of  lever  L. 

By  removing  the  arrangement  for  light  stimulus  the  pair 
of  stimuli,  sound  and  shock,  may  be  given  together;  or  by 
getting  out  of  series  with  the  induction  coil,  the  paired  stimuli, 
sound  and  light,  may  be  given.  Likewise  it  is  possible  to 
eliminate  any  two  stimuli  and  administer  a  third  singly. 
When  light  is  presented  singly  a  small  rubber  plate  is  attached 
to  the  posterior  side  of  the  stimulus  lever  (L)  to  eliminate 
the  sound.  In  all  these  cases  it  is  seen  that  the  chronoscope 
release  is  mechanical,  by  means  of  Shi.  Fig.  2  by  means  of 
dotted  lines  from  the  binding  posts  suggests  the  wiring  ar- 
rangement for  electrical  operation  of  the  chronoscope.  When 


A  NEW  CHRONOSCOPY 


41 


the  current  is  used  the  two  cords  are  serviceable  to  set  the 
pendulum  armature  and  to  throw  the  reaction  index  back  to 
zero. 

It  is  seen  that  the  mechanical  device  can  be  operated  only 
when  the  experimenter  and  reagent  are  at  close  range.  When, 
however,  it  is  desired  to  give  stimuli  from  a  distance  or  to 
have  the  reaction  from  another  room  the  electrical  arrange- 
ment mentioned  above  must  be  employed.  The  reaction 
movement  called  for  by  the  apparatus  is  in  all  cases  of  the 
break-circuit  variety.  The  chronoscope  may  be  put  to  the 
same  tasks  that  are  attempted  by  any  type  of  electrical 
chronoscope,  at  the  same  time  affording  a  mechanical  arrange- 
ment that  would  seem  to  meet  the  objections  of  those  opposed 
to  the  electric  chronoscope. 

METHOD  OF  LAYING  THE  CHRONOMETRIC  SCALE 
A  chronoscope  is  a  device  for  visualizing  intervals  of  time 
by  freely  initiating  or  terminating  the  regular  movement  of 
either  a  point  along  a  graduated  scale  or  a  graduated  scale 
past  a  point,  each  division  of  the  scale  being  the  space  tra- 
versed in  a  given  unit  of  time.  Many  a  chronoscope  has  been 
devised  with  perfect  balance  and  bearings  but  failed  because 
its  scale  was  too  largely  a  matter  of  speculation.  The 
chronometric  scale  is  the  real  chronoscope — propelling  the  scale 
or  moving  an  index  uniformly  along  it  are  comparatively 
easy  accessories. 

The  possibility  of  laying  a  definite  chronometric  scale  was 
one  of  the  factors  that  prompted  the  present  device.  Fig.  I 
shows  the  method  of  deriving  the  scale  and  of  placing  it  upon 
the  chronoscope  disc.  One  of  a  pair  of  synchronized  differ- 
ential tuning  forks  of  256  v.d.  frequency  is  loaded  with  a  small 
aluminum  feather  (A\)  by  means  of  a  stiff  wax.  It  is  then 
sounded  with  its  companion,  the  number  of  beats  per  second 
counted  and  its  vibration-rate  calculated.  Then  by  means  of 
wax  another  aluminum  feather  (A^  is  attached  to  the  second 
fork,  and  small  increments  are  made  to  the  wax  until  the  beats 
disappear.  The  forks  are  again  synchronical  and  their  vi- 
bration-rate is  that  formerly  calculated.  They  are  mounted 


42  JOHN  W.   TODD 

as  shown  in  Fig.  I  in  such  manner  that  feather  AI  touches 
the  smoked  drum  of  a  kymograph. and  feather  A\  rests  upon 
the  smoked  edge  of  the  chronoscope  disc.  Into  this  arrange- 
ment a  third  member  is  brought,  a  Morse  key  rearranged  for 
break-circuit  contact,  and  bearing  two  aluminum  feathers  at 
the  end  of  its  shaft  beneath  the  button  (P).  One  of  these 
feathers  is  adjusted  to  lie  within  the  same  radius  of  the  disc 
as  the  tuning  fork  feather,  A\,  and  the  other  is  squared  with 
the  point  of  the  feather  upon  the  kymograph. 

After  the  disc  is  brought  to  its  initial  position  and  the 
circuit  to  the  electro-magnet  (EM)  is  closed,  it  is  seen  that  a 
pressure  upon  the  button  (P),  which  short-circuits  the  current 
to  EM,  will  release  the  disc.  At  the  same  time  a  mark  will 
be  recorded  upon  the  kymograph  and  another  upon  the 
smoked  edge  of  the  chronoscope  disc.  The  entire  procedure 
is  as  follows:  Start  the  forks,  and  with  the  hand  suddenly 
revolve  the  drum  of  the  kymograph,  having  disconnected  it 
from  the  clock-work  mechanism,  and  with  the  other  hand 
press  upon  the  button  (P)  at  least  twice  in  quick  succession. 


FIG.  4. 

Lower  Fig.  4  is  the  .kymograph  record  of  the  pressures, 
and  upper  Fig.  4  is  a  diagrammatic  view  of  the  disc  record 
straightened  and  brought  into  relationship  with  it.  The  time 
value  of  the  distance  o-y  on  the  chronoscope  scale  is  readily 
counted  off  from  the  distance  on  the  kymograph  scale,  A-B. 
In  laying  the  chronoscope  scale  it  is  necessary  only  to  read 
toward  o  from  the  point  y  to  establish  the  first  distinguishable 
chronometric  value  from  o.  There  will  always  be  the  space 
o-x  whose  time  value  in  toto  is  known  but  whose  individual 
waves  are  too  close  together  to  be  distinguished. 

After  setting  the  chronographic  records  with  shellac  the 
scale  of  time  values  is  engraved  upon  the  chronoscope  disc 


A  NEW  CHRONOSCOPE  43 

at  grade  points  located  by  producing  a  radius  of  the  disc 
through  the  crest  of  each  tuning-fork  wave.  The  time  value 
of  each  wave-length  was  4*  which  save  in  the  case  of  waves 
near  x  is  graded  in  four  equal  parts,  or  to  the  ia.  This 
chronographic  method  of  laying  the  scale  is  superior  to  the 
method  of  employing  sparks  produced  by  an  induction  coil 
with  a  tuning-fork  interrupter  because  the  sparks  deviate 
considerably  in  making  the  aerial  gap,  and  fail  to  indicate  the 
true  location  of  the  scale. 

In  order  to  test  the  reliability  of  the  chronoscope  a  control 


FIG.  5. 

apparatus  (Fig.  5)  is  used  consisting  of  a  shaft  with  a  polished 
metal  point  so  poised  that  its  axis  if  produced  is  a  secant  of 
the  pendular  arc.  This  shaft  is  carried  by  a  comparatively 
facile  spring  in  a  rigid  base.  When  the  pendulum  strikes  the 
shaft  it  is  pushed  back  breaking  the  circuit  at  x,  thus  releasing 
the  chronoscope  index  and  recording  upon  the  scale  the 
interval  between  the  release  of  the  pendulum  and  its  striking 
the  shaft.  The  values  given  below  are  the  averages  of  12 
groups  of  control  tests  of  10  trials  each,  or  120  tests.  The 
mechanical  release  was  used  in  the  tests. 

Average  Interval  Average  Variation 

519.4°"  0.84°" 

520.2  1.08 

520.4  0.64 

520.1  0.18 

520.4  0.64 

521.4  0.80 

5I9-S  i-oo 

519.0  i.oo 

520.3  0.42 

519-8  0.48 

519-9  0.72 

522.0°"  Gross  Av.  520.20"  0.42°"  Gross  Av.  0.68°" 


44  JOHN  W.   TODD 

The  present  device  by  means  of  its  adjustable  discs  (Di 
and  Z)2,  Fig.  i)  affords  a  tachistoscope  that  is  fairly  service- 
able.1 The  point-exposure  time  may  be  read  off  from  the 
chronometric  scale,  and  affords  a  maximum  point  exposure 
of  420'.  The  stimuli  are  held  by  a  clip  behind  the  discs  and 
are  seen  through  the  sector  of  the  compound  disc.  B,  in 
Fig.  3,  is  a  diagram  showing  a  tachistoscopic  attachment  for 
the  stimulus  key  (Stim.  K)  making  it  possible  to  expose 
words,  colors,  etc.,  in  a  rectangular  aperture  for  reaction 
experiments  in  discrimination,  cognition,  choice  and  asso- 
ciation. The  screen  is  large  enough  to  conceal  the  operations 
of  the  experimenter  from  the  reagent.  By  using  the  rubber 
plate  under  the  sound  hammer  the  exposures  are  made  almost 
noiselessly. 

SUMMARY  OF  THE  SPECIAL  FEATURES  OF  THE  CHRONOSCOPE 

1.  It  allows  either  mechanical  or  electrical  release  of  the 
time  scale,  involving  in  each  case  the  same  parts,  and  making 
it  possible   to  work  where  a  steady  electric  current  is   not 
available. 

2.  The    reaction    mechanism    may    be    operated    either 
mechanically  or  electrically. 

3.  The  device  makes  it  possible  to  lay  a   chronometric 
scale  whose  units  can  be  exactly  placed  to  within  a  short  dis- 
tance of  the  zero  point,  and  whose  total  value  is  exactly  known. 

4.  By  means  of  an  attachment  time  exposures  may  be 
made  that  are  measured  off  on  the  chronometric  scale,  and 
the  variety  of  compound-reaction  stimuli  can  be  given. 

1  In  his  "Mental  and  Physical  Tests — Simpler  Processes,"  1914,  pp.  263  ff., 
Whipple  figures  and  describes  a  disc  tachistoscope  of  his  own  construction  and  one 
now  commonly  in  use.  In  his  instrument  the  point-exposure  times  are  calculated 
from  the  relative  positions  of  weights  upon  the  two  counterbalancing  arms  that 
route  the  disc.  In  the  present  arrangement  the  times  are  shown  on  the  chronometric 
scale. 


XVIII.  PRACTICE  IN  ASSOCIATING  COLOR-NAMES 
WITH  COLORS1 

BY  WARNER  BROWN 

It  has  long  been  known  that  the  process  of  recognizing 
and  naming  a  color  takes  more  time  than  the  process  of  recog- 
nizing and  naming  an  isolated  printed  word,  such  as  the  word, 
for  example,  which  designates  the  same  color.2  The  following 
experiments  represent  an  attempt  to  gain  a  clearer  under- 
standing of  this  phenomenon. 

The  first  hypothesis  which  presented  itself  was  that 
words  can  be  recognized  and  named  more  rapidly  because 
we  have  had  more  practice  in  doing  this  than  in  naming 
colors.3  Accordingly  a  practice  experiment  was  contrived 
on  the  basis  of  Cattell's  familiar  color-naming  test.4  Experi- 

1  From  the  Psychological  Laboratory  of  the  University  of  California. 

2  James,  W.,  'Principles  of  Psychology,'  1890,  Vol.  I.,  p.  559.     Cattell,  J.  McK. 
'Ueber  die  Zeit  der  Erkennung  und  Benennung  von  Schriftzeichen  Bildern  und  Farben, 
Philos.  Stud.,  Vol.  2,  1885,  pp.  635-650. 

3  This  explanation  of  the  phenomenon  is  clearly  stated  by  Cattell  in  the  account 
of  its  discovery  which  he  gives  under  the  title,  'The  Time  it  Takes  to  See  and  Name 
Objects'  (Mind,  Vol.  II,  1886,  p.  65).      He  says,  "The  time  was  found  to  be  about 
the  same  (over  \  sec.)  for  colors  as  for  pictures,  and  about  twice  as  long  as  for  words 
or  letters.     Other  experiments  I  have  made  show  that  we  can  recognize  a  single  color 
or  picture  in  a  slightly  shorter  time  than  a  word  or  letter,  but  take  longer  to  name  it. 
This  is  because  in  the  case  of  words  and  letters  the  association  has  taken  place  so 
often  that  the  process  has  become  automatic,  whereas  in  the  case  of  colors  and  pictures 
we  must  by  a  voluntary  effort  choose  the  name." 

The  same  interpretation  is  given  by  J.  O.  Quantz  in  his  monograph,  'Problems 
in  the  Psychology  of  Reading,'  PSYCHOL.  REV.  MONOG.,  No.  5,  1897,  p.  10.  "The 
association  is  of  the  same  sort  in  words  as  in  forms  or  colors,  for  the  connection  between 
the  written  symbols  and  the  spoken  sound  of  any  given  word  is  just  as  arbitrary  as  is 
that  between  a  particular  geometrical  form  and  its  name  as  uttered.  But  the  asso- 
ciation between  forms  or  colors  and  their  names,  being  less  necessary  than  between 
written  and  printed  (spoken?)  words  has  been  less  frequently  formed  and  the  former 
has  remained  a  voluntary  process  while  the  latter  has  become  automatic  through 
repetition." 

4  Cattell   and   Farrand,   'Physical   and   Mental  Measurements   of   Students   of 
Columbia  University,'  PSYCHOL.  REV.,  Vol.  3,  1896,  p.  642.     Wissler,  C.,  'The  Correla- 
tion of  Mental  and  Phsyical  Tests,'  PSYCHOL.  REV.  MONOG.,  No.   16,   1901,  p.  8. 
Hollingworth,  H.  L.,  '  The  Influence  of  Caffein  on  Efficiency,'  Arch,  of  Psychol.,  No.  22, 
1912,  p.  16. 

45 


46  WARNER  BROWN 

ence  had  shown  that  the  Columbia  test  was  weak  in  the  fol- 
lowing points:  Not  all  the  color  names  were  equally  familiar; 
they  were  not  all  equally  hard  to  say  (for  example  red,  yellow; 
blue,  violet);  there  were  strong  brightness  contrasts  between 
some  of  the  colors;  the  chance  arrangement  of  the  colors 
resulted  in  some  bad  sequences;  the  one-centimeter  squares 
were  too  small,  making  it  difficult  to  'keep  the  place'  with  the 
eye.  The  test  was  accordingly  modified  in  these  respects: 
The  color  squares  were  increased  in  size  to  one  inch;  the 
sequence  was  so  arranged  that  no  color  square  was  placed 
next  to  another  of  the  same  color  and  a  color  was  not  per- 
mitted to  occur  less  than  twice  nor  more  than  three  times  in 
any  row;  only  four  different  colors  were  used  in  any  one  set 
and  these  were  all  either  'light'  (white,  pink,  brown,  gray) 
or  'dark'  (black,  red,  blue,  green);1  the  colors  all  had  one- 
syllable  names;  all  of  these  names  were  highly  familiar.2 

It  was  expected  on  the  hypothesis  of  Cattell  and  Quantz 
that  sufficient  practice  would  make  it  possible  to  read  off 
the  color  names  as  rapidly  from  the  colors  themselves  as 
from  a  printed  list.  If  the  difference  in  speed  depends  upon 
previous  practice  it  should,  by  further  practice,  be  possible 
to  reduce  the  time  consumed  in  reading  colors  but  not  possible 
to  reduce  to  any  considerable  extent  the  time  required  to  read 
a  list  of  words.  In  order  to  test  the  truth  of  this  hypothesis 
it  was  necessary  to  show  not  only  that  the  speed  of  color 
naming  can  be  increased  by  practice  but  also  that  the  speed 
of  reading  words  can  not  be  increased  so  much  by  an  equal 
amount  of  practice.  For  the  practice  in  reading  words,  lists 
were  typewritten  with  the  one  hundred  color-names  arranged 
in  the  same  order  as  the  colors  themselves.  The  words  in 

1  The  colors  used  were  the  papers  supplied  by  the  Milton  Bradley  Company,  of 
Springfield,  Mass.,  under  the  following  designations:  Black,  White,  Neutral  Gray 
No.  2,  Engine  Colored  Paper  No.  26  (brown)  and  No.  iB  (pink),  Red,  Green,  and  Blue. 

1  The  modified  form  of  the  Columbia  test  recommended  by  Woodworth  and  Wells, 
'Association  Tests/  PSYCHOL.  REV.  MONOG.,  No.  57,  1911,  p.  49,  meets  most  of  the 
difficulties  mentioned  above,  but  unfortunately  it  was  not  published  until  after  the 
present  experiments  were  partly  completed.  It  may  be  noted  that  in  the  Woodworth 
and  Wells  test  the  colors  appear  on  a  white  background  whereas  in  the  form  here  used 
the  squares  were  larger  and  juxtaposed  without  background. 


COLOR-NAMES  47 

each  line  were  separated  by  a  comma  and  one  space;  the  lines 
were  separated  by  a  triple  space.  For  each  set  of  colors  there 
were,  of  course,  four  distinct  lists  of  words,  corresponding  to 
the  four  arrangements  of  colors  which  were  encountered  on 
beginning  in  the  four  different  corners  of  the  color-set.  For 
every  practice  trial  in  associating  the  colors  with  their  names 
there  was  a  practice  in  reading  the  words  from  the  corre- 
sponding list. 

A  record-blank,  including  complete  directions,  was  given 
to  each  worker  at  each  practice  sitting;  it  read  as  follows: 

DIRECTIONS  FOR  THE  EXPERIMENT  ON  NAMING  COLORS 

There  are  two  boards  of  colors.  Each  board  contains  25  squares  of  each  of  4 
colors,  and  there  is  a  different  color  in  each  corner  of  the  board.  There  are  4  type- 
written lists  of  colors  for  each  of  the  boards,  and  each  list  begins  with  the  name  of 
the  color  in  one  corner  of  the  board,  and  gives  the  names  of  the  colors  in  the  order  of 
their  appearance  on  the  board. 

The  purpose  of  the  experiment  is  to  measure  the  maximum  rate  of  speaking  when 
reading  the  lists  of  words  or  naming  the  colors,  and  to  see  how  much  this  rate  can  be 
increased  by  practice. 

First  day's  work.  Take  the  time  with  a  stop-watch  for  reading  aloud,  as  fast 
as  you  possibly  can,  the  words  on  the  typewritten  list  beginning  with  Black.  Enter 
the  time,  in  seconds  and  fifths  of  a  second,  opposite  "List  black"  in  the  table  below. 
Then  take  the  time  for  calling  out  the  names  of  the  colors,  as  fast  as  you  possibly  can, 
from  the  board,  beginning  with  Black  in  the  upper  left-hand  corner  and  reading  by  rows 
from  left  to  right.  Enter  the  time  opposite '  Board  black '  in  the  table.  Then  enter  the 
time  for  each  of  the  remaining  items  in  the  table,  being  careful  to  take  them  in  the 
order  indicated  by  the  numbers. 

1.  List  black 3.  List  white 

2.  Board  black 4.  Board  white 

5.  List  blue 7.  List  brown 

6.  Board  blue 8.  Board  brown 

9.  List  green n.  List  pink 

10.  Board  green 12.  Board  pink 

13.  List  red .  15.  List  gray 

14.  Board  red 16.  Board  gray 

Second  and  succeeding  days.  Use  only  one  board  of  colors  and  the  lists  which 
belong  with  it.  Do  not  look  at  the  other  board  or  its  lists,  nor  allow  any  one  to  read 
them  in  your  hearing.  Record  the  times  for  the  right  (left)1  hand  half  of  the  table  in 
the  order  given,  and  do  nothing  with  the  other  half  of  the  table. 

Twelfth  day.     Exactly  the  same  as  the  first  day. 

Forty-five    students    took    part    in    the    experiment.     All 

1  If  the  subject  was  to  practice  the  'dark'  colors  the  word  right  was  expunged; 
if  he  was  to  practice  the  'light'  colors  the  word  left  was  expunged. 


48 


WARNER  BROWN 


practiced  for  twelve  practice-periods.  Most  of  them  worked 
twice  a  week,  but  a  few  practiced  daily.  Twenty-five  of  the 
forty-five  were  women.  Twenty,  of  whom  ten  were  women, 
practiced  on  the  'dark'  colors.  Twenty-five,  of  whom  fifteen 
were  women,  practiced  on  the  'light'  colors.  As  no  essential 
difference  appears  between  the  light  and  dark  colors  the  data 
have  been  combined  for  the  entire  forty-five  workers.1 

The  condensed  data  are  presented  in  Table  I.     The  table 

TABLE  I 

GAIN  BY  PRACTICE  IN  NAMING  COLORS  AND  READING  WORDS 

Average  of  45  Subjects 
The  time  is  the  average  of  the  4  trials  made  each  day. 


Colors  : 

Colors: 

Colors: 

Words: 

Words: 

Words: 

Ratio: 

Av.  Time 

Av.  Gain 

Av.  Gain 

Av.  Time 

Av.  Gain 

Av.  Gain 

Time  for 

Day. 

Required 
to  Name 

in  Speed 
Over 

in  Speed 
Over 

Required 
to  Read 

in  Speed 
Orer 

in  Speed 
Over 

Colors 
Divided 

Them, 
Sees. 

ist  Day, 
Sees. 

ist  Day, 
Per  Cent. 

Them, 
Sees. 

ist  Day, 
Sees. 

ist  Day, 
Per  Cent. 

by  Time 
for  Words 

j 

S5.8 

35-2 

•59 

2 

50.9 

4-9 

8.8 

33-o 

2.2 

6.3 

•54 

3 

46.4 

9.4 

16.8 

31-6 

3-6 

10.2 

•47 

4 

45-2 

10.6 

19.0 

30.8 

44 

12.5 

.46 

5 

43-7 

12.  1 

21.7 

30.2 

5-o 

I4.2 

•44 

6 

42.8 

13.0 

23.2 

30.4 

4.8 

13-6 

.41 

7 

42.4 

134 

24.0 

29.9 

5-3 

I5-I 

.42 

8 

41.4 

144 

25.8 

29-5 

57 

16.2 

.40 

9 

41.4 

144 

25.8 

29.4 

5-8 

16.5 

.41 

10 

41.1 

147 

26.4 

29.0 

6.2 

17.6 

.42 

ii 

40.7 

I5-I 

27.1 

29.4 

5.8 

16.5 

•38 

12 

41.4 

144 

25.8 

29-3 

5-9 

16.8 

.41 

shows  the  average  time  required  by  the  45  subjects  for  naming 
the  100  colors  and  for  reading  aloud  the  100  words.  The  time 
is  the  average  for  the  four  trials  which  were  made  each  day.2 

1  On  the  first  day  of  work,  when  records  were  made  for  all  of  the  subjects  with  both 
light  and  dark  sets  (t.  e.,  the  first  practice  record  with  one  set  and  the  first  check  record 
with  the  other  set)  the  times  were  as  follows: 

Time  required  to  name  100  dark  colors  56.0  sec.;  100  'dark'  words  36.0  sec. 

Time  required  to  name  100  light  colors  55^8  sec.;  'light'  words  35.2  sec. 
This  insignificant  advantage  of  the  light  sets  remains  unchanged  through  the  course  of 
practice.     Most  persons  prefer  to  work  with  the  light  colors  on  esthetic  grounds. 
Some  subjects  complain  of  getting  the  tongue  twisted  around  the  words,  blue  and 
black  in  the  dark  sets  because  of  the  identity  of  their  initial  sounds. 

1  These  four  trials  did  not  differ  greatly  from  one  another.  As  a  rule  the  first 
trial  was  better  than  the  others  except  that  on  the  first  day,  and  to  some  extent  on  the 


COLOR-NAMES 


49 


The  practice  gains  are  shown  both  in  seconds  and  in  per  cent. 
In  both  cases  the  amount  of  gain  is  computed  on  the  basis  of 
the  speed  on  the  first  day  of  work.  The  table  further  shows 
the  ratio  between  the  time  required  for  colors  and  the  time 
required  for  words. 

In  Table  la  the  records  are  shown  for  the  tests  which 

TABLE  la 

TESTS  ON  UNPRACTICED  SETS,  FOR  WHICH  RECORDS  WERE  MADE  ON  THE  IST  AND 

I2TH  DAYS  OF  PRACTICE 
Column  headings  as  above. 


I 

12 

55-9 
474 

8.5 

15.2 

35.8 
32.0 

3,8 

10.6 

i.56 
1.48 

TABLE  Ib 

SEPARATE  STATEMENT  FOR  MEN  AND  FOR  WOMEN  FOR  THE  IST  AND  I2TH  DAYS  OF 
THE  REGULAR  PRACTICE  WORK 

Figures  for  Women  in  Italics 
Headings  as  above. 


I 

58.9 

35.6 

1.66 

I 

53-3 

35-i 

1.52 

12 

42.0 

16.9 

28.7 

29.9 

5-7 

16.0 

1.40 

12 

39-9 

13-4 

25.1 

2Q.O 

6.1 

1.74 

1-38 

were  made  on  the  first  and  last  days  with  different  sets  of 
colors  and  words. 

In  Table  Ib  the  data  of  the  first  and  last  days  are  arranged 
to  display  the  fact  that  women  excel  men  in  speed  in  naming 
colors,  but  that  men  improve  more  with  practice.1 

From  the  data  of  Table  I.  and  from  an  inspection  of  the 
curves  of  Fig.  i  it  can  be  seen  that  the  hypothesis  on  which 
this  experiment  was  based  is  probably  not  true.  At  the  end 

second  day,  there  was  improvement  from  trial  to  trial.  The  following  figures  were 
obtained  by  averaging  the  records  for  the  last  ten  days  of  practice: 

ist  trial  2d  trial  sd  trial  4th  trial 

Time  for  100  colors 42.3  42.3  43.0  42.8 

Time  for  100  words 29.0  30.4  29.9  30.5 

Evidently  the  practice  gains  during  this  period  occur  in  the  intervals  between  sittings, 
'overnight,'  and  not  during  the  course  of  a  sitting. 

1  The  superiority  of  women  in  naming  colors  has  been  observed  by  Woodworth 
and  Wells,  PSYCHOL.  REV.  MONOG.,  No.  57,  1911,  p.  51,  and  by  Wissler,  PSYCHOL. 
REV.  MONOG.,  No.  16,  1901,  p.  17. 


WARNER  BROWN 


of  twelve  periods  of  practice  it  is  evident  that  only  a  very 
slight  further  increase  of  speed  in  naming  colors  can  be  an- 
ticipated, no  matter  how  much  more  practice  is  taken;  yet 
the  absolute  rate  in  naming  colors  remains  much  slower  than 
the  rate  of  reading  the  same  words  from  the  list  and  is  even 
slower  than  the  word  rate  was  before  the  beginning  of  practice. 
Furthermore  the  life-long  practice  which  we  have  had  in 
reading  words  has  not  brought  that  function  to  a  maximum 
speed;  on  the  contrary  it  shows  an  amount  of  practice-im- 
provement almost  proportional  to  the  improvement  shown 
in  naming  the  colors.  For  every  second  gained  in  naming 
colors  at  any  stage  of  practice  approximately  half  a  second 
has  been  gained  in  reading  words.  The  ratio  between  speed 


Sees. 

60 

55 
50 
45 
40 

35 
30 
25 


Colors 


Words 


5         6          7 
Days  of  Practice. 


10       ii 


12 


in  color  naming  and  speed  in  word  reading  (the  last  column  of 
Table  I.)  shows  no  indication  of  approaching  unity.1 

From  these  data  it  seems  safe  to  conclude  that  the  dif- 

1  The  statements  of  this  paragraph  are  true  not  only  for  the  average  results"given 

the  table,  but  for  each  individual  subject  who  took  part  in  the  experiment]     No 

statement  of  the  variability  or  probable  error  of  the  measurements  has  been  made 

tuse  such  a  statement  could  have  no  direct  bearing  upon  the  interpretation  of  the 

the  present  connection.    The  individual  differences  in  absolute  speed  were 

very  large,  but  they  do  not  in  any  way  affect  the  results. 


COLOR-NAMES  51 

ference   in    speed   between    color-naming   and   word-reading 
does  not  depend  upon  practice. 

Further  confirmation  of  this  conclusion  is  found  in  the 
fact  that  the  effects  of  training  in  reading  words  are  specific 
for  the  particular  words  read  and  do  not  extend  to  other 
words.     It  will  be  recalled  that  each  person  was  trained  upon 
either  the  Might'  or  the  'dark'  set,  but  that  a  test  was  made, 
at  the  first  and  last  sitting,  of  his  speed  with  the  other  set 
(the  one  he  did  not  practice).     The  results  of  these  tests  are 
indicated  in  Table  la.     The  speed  on  the  unpracticed  sets  at 
the  end  of  twelve  days  of  practice  is  better  than  on  the  prac- 
ticed sets  on  the  second  day  of  practice,  but  not  so  good  as 
on  the  third  day.     In  other  words,  three  days  of  direct  practice 
are  better  than  two  days  of  direct  practice  plus  ten  intervening 
days  of  indirect  practice.     This,  too,  in  a  case  where  the 
conditions  regarding  eye-movement  and  general  adaptation 
to  work  might  lead  us  to  anticipate  a  considerable  amount  of 
transference  of  practice  or  ' formal'  training.     In  the  present 
connection  the  significant  fact  is  that  the  amount  of  transfered 
practice  is  but  little  greater  in  the  case  of  reading  words  than 
in  the  case  of  naming  colors.     Apparently  we  must  have 
practice  in  reading  specific  words  before  we  can  attain  great 
proficiency  in  reading  them.     It  can  not,  therefore,  be  safely 
asserted  that  we  read  color  names  faster  than  we  name  colors 
simply  because  of  the  large  amount  of  practice  which  we  have 
had  in  reading  words  in  general. 

i 

THE  SECOND  EXPERIMENT 

It  now  seemed  clear  that  the  effects  of  previous  practice 
do  not  afford  a  sufficient  explanation  of  the  difference  in 
speed  between  color-naming  and  word-reading.  Accordingly 
the  problem  was  attacked  from  another  quarter.  The  intro- 
spections of  practically  all  of  the  students  who  had  taken 
part  in  the  first  experiment  agreed  upon  one  point:  It  is  easier 
to  speak  a  printed  word  than  to  name  a  color  because  when 
you  want  to  name  a  color  you  have  first  to  think  of  the  name 
(the  word)  and  then  speak  it,  whereas  the  printed  word  can 


52 


WARNER  BROWN 


be  uttered  without  your  having  to  think  of  anything.  The 
observations  of  our  foreign-born  students  were  particularly 
clear  on  this  point.1 

On  the  basis  of  these  introspections  the  hypothesis  was 
formed  that  the  process  of  color-naming  would  be  facilitated 
by  suggesting  the  word  at  the  moment  the  color  was  pre- 
sented. For  actual  experiment  color-sets  were  prepared 
which  had  entire  words  or  parts  of  words  printed  on  the  face 
of  the  colors  themselves. 

Nineteen  students  finally  completed  all  the  stages  of  this 
experiment.  They  were  first  given  fifteen  periods,  twice  a 
week,  of  practice  in  reading  the  lists  and  naming  the  colors 
from  sets  upon  which  nothing  was  printed,  just  as  in  the 
previous  experiment.  The  color-set  was  named  over  three 
times  at  each  sitting  and  the  list  of  words  was  read  once. 

TABLE  II 


Day 

Time  Required  to  Name 
100  Colors,  Sees. 

Time  Required  to  Read 
100  Words,  Sees. 

Ratio:  Time  for  Colors 
Divided  by  Time  for  Words 

I 

53.8 

35-5 

•52 

2 

48.2 

32.7 

•47 

3 

46.2 

31-7 

•45 

4 

45-3 

3I-I 

.46 

5 

42.9 

29.8 

44 

6 

42.2 

30.2 

•39 

7 

4i-3 

29.4 

.41 

8 

40.7 

28.8 

.41 

9 

39-3 

28.5 

.38 

10 

39-5 

29.0 

.36 

ii 

40.4 

28.8 

.40 

12 

38.8 

27.6 

.41 

13 

38.2 

27.7 

.38 

H 

37-9 

27.6 

•37 

15 

37-i 

27.4 

•35 

Only  the  'light'  set  was  used.  The  words  of  the  list,  instead 
of  being  printed  in  a  regular  list  with  the  ten  words  of  a  line 
separated  by  commas,  were  now  typewritten  on  separate 
squares  of  paper,  one  inch  square,  which  were  mounted  on  a 
board  just  as  the  color-squares  were  mounted,  so  that  the 
eye-movements  involved  were  as  nearly  as  possible  the  same 
as  for  the  colors.  The  data  for  these  fifteen  preliminary 

1  Three  Japanese  and  one  Armenian  took  part  in  the  experiment,  but  their  records 
are  not  included  in  the  tabulations. 


COLOR-NAMES  53 

practice  sittings  are  given  in  Table  II.     The  figures  agree 
substantially  with  those  presented  in  Table  I.1 

After  the  preliminary  practice,  which  was  only  intended 
to  bring  the  students  to  such  a  point  that  their  speed  for  simple 
colors  and  lists  of  words  would  be  nearly  uniform  from  day  to 
day,  experiments  were  begun  with  sets  of  colors  arranged 
just  like  the  others  except  for  words  or  letters  typewritten 
upon  them.  The  following  transcript  of  the  directions  gives 
a  sufficient  outline  of  the  course  of  this  experiment. 

DIRECTIONS 

Sixteenth  day.  Read  the  list  of  words  beginning  with  brown:  then  read  the 
simple  color-set  beginning  with  gray.  Then  read  color-set  2  with  b  on  brown;  then 
set  3  with  w  on  white;  then  set  6,  b  on  brown,  w  on  white,  p  on  pink,  and  g  on  gray. 

Seventeenth  day.  Read  the  list  of  words  beginning  with  gray:  then  the  simple 
color-set  beginning  with  pink.  Then  read  color-set  7,  gr  on  gray;  then  set  4,  p  on 
pink;  then  set  10,  br  on  brown,  wh  on  white,  gr  on  gray,  and  p  on  pink. 

Eighteenth  day.  Read  the  list  of  words  beginning  with  brown:  then  the  simple 
color-set  beginning  with  gray.  Then  read  color-set  II,  own  on  brown;  then  set  12,  ink 
on  pink;  then  set  15,  own  on  brown,  ink  on  pink,  ite  on  white,  and  ay  on  gray. 

Nineteenth  day.  Read  the  list  of  words  beginning  with  gray:  then  the  simple 
color-set  beginning  with  pink.  Then  read  color-set  16,  with  full  words  on  all  colors. 
Then  read  the  simple  color-set  again  beginning  with  brown.  Then  read  color-set  16, 
full  words,  again. 

Twentieth  day.  Read  the  list  of  words  beginning  with  pink:  then  the  simple 
color-set  beginning  with  gray.  Then  read  color-set  16,  with  full  words  on  all  colors, 
two  times.  Then  read  the  simple  color-set  beginning  with  brown. 

Twenty-first  day.  Read  the  list  of  words  beginning  with  brown:  then  the  simple 
color-set  beginning  with  gray.  Then  read  color-set  13,  with  ite  on  white;  then  set  14, 
with  ay  on  gray;  then  set  15,  own  on  brown,  ite  on  white,  ink  on  pink,  and  ay  on  gray. 

Twenty-second  day.  Read  the  list  of  words  beginning  with  gray:  then  the  simple 
color-set  beginning  with  pink.  Then  read  color-set  8,  with  br  on  brown;  then  set  9, 
with  wh  on  white;  then  set  10,  br  on  brown,  gr  on  gray,  wh  on  white,  and  p  on  pink. 

Twenty-third  day.  Read  the  list  of  words  beginning  with  brown:  then  the  simple 
color-set  beginning  with  gray.  Then  read  color-set  4,  with  p  on  pink;  then  set  5 
with  g  on  gray;  then  set  6,  with  b  on  brown,  p  on  pink,  w  on  white,  and  g  on  gray. 

The  data  for  the  last  eight  days  of  this  experiment  are 
presented  in  Table  III.  They  are  combined  in  the  table  so 
that  wherever  two  records  of  the  same  kind  were  obtained  on 

1  It  may  be  noted  that  the  rate  of  improvement  is  here  almost  the  same  as  in  the 
earlier  experiment  in  spite  of  the  fact  that  the  colors  were  practiced  only  three  times 
and  the  words  only  once  instead  of  four  times  as  in  the  earlier  experiment.  In  view 
of  the  fact  already  mentioned  that  the  first  trial  of  a  sitting  is  usually  the  best  there 
is  reason  for  believing  that  nearly  the  same  results  could  be  obtained  in  this  work  by 
one  trial  per  day  as  by  four  trials  per  day. 


54 


WARNER  BROWN 
TABLE  III 


TIME  REQUIRED  TO  NAME  100  COLORS,  TO  READ  100  WORDS,  AND  TO  NAME  100 
COLORS  WITH  THE  HELP  OF  PRINTED  CUES 


Day 

Simple 
Colors 

Words 

Colors  on  Which  the  Following  Letters  Were  Printed  as  Cues 
to  Help  in  Naming  the  Colors 

40.8    An  initial  consonant  on  one  color. 

16 

38.1 

28.1 

39.4    An  initial  consonant  on  each  color. 

17 

36.6 

27-6 

38.8     Initial  pair  of  consonants  on  one  color. 
36.4     Initial  pair  of  consonants  on  each  color. 

38.0    Vowel  and  final  consonant  on  one  color. 

18 

36.6 

27.6 

38.4    Vowel  and  final  consonant  on  each  color. 

19 

36.1 

27.6 

28.6     Entire  word  on  each  color. 

20 

357 

27.2 

28.3     Entire  word  on  each  color. 

37.3     Vowel  and  final  consonant  on  one  color. 

21 

36.1 

27.2 

36.4    Vowel  and  final  consonant  on  each  color. 

36.9     Initial  pair  of  consonants  on  one  color. 

22 

3S-o 

27.9 

'32.3     Initial  pair  of  consonants  on  each  color. 

35.2     Initial  consonant  on  one  color. 

23 

35-3 

27.9 

34.6     Initial  consonant  on  each  color. 

the  same  day  only  their  average  appears.  When  the  entire 
words  are  printed  on  the  colors  it  is  possible  to  read  the 
words  without  attending  to  the  colors,  but  even  in  that  case 
the  average  speed  is  not  so  great  as  when  the  words  are  read 
alone  without  the  colored  background,  as  may  be  seen  in  the 
records  of  days  nineteen  and  twenty.  After  having  practiced 
with  the  full  words  on  the  colored  backgrounds  some  of  the 
students  found  it  possible  to  read  the  color-names  directly 
upon  seeing  the  initial  letters  without  considering  the  back- 
ground. This  accounts  for  the  fact  that  the  records  for  the 
twenty-second  and  twenty-third  days,  with  initials,  are  con- 
siderably better  than  the  records  for  the  sixteenth  and  seven- 
teenth days  under  the  same  conditions. 

From  the  results  of  this  part  of  the  experiment  it  may  be 
concluded  that  the  association  process  in  naming  simple 
objects  like  colors  is  radically  different  from  the  association 
process  in  reading  printed  words.  The  presence  of  a  visual 
symbol  of  the  sound  does  not  greatly,  if  at  all,  facilitate  the 
process  of  association  between  color  and  color-name.  Pho- 
netic symbols  which  might  suggest  the  name  of  the  color  do 
not  help  us  in  naming  it  unless  they  are  so  clear  that  they 
enable  us  to  read  the  name  itself  directly  without  going 
through  the  process  of  naming  the  color.  The  one  association 


COLOR-NAMES  55 

process  does  not  reinforce  the  other.  The  introspections  of  all 
the  subjects  confirm  the  figures  in  declaring  that  the  letters 
printed  on  the  colors  do  not  serve  as  helpful  cues  or  prompts, 
but  on  the  contrary  actually  interfere  with  the  process  of 

association.1 

CONCLUSION 

The  conclusions  of  these  experiments  seem  to  be  entirely 
negative.  No  facts  have  been  adduced  to  explain  why  more 
time  is  required  to  associate  speech  movements  with  a  color 
than  with  the  corresponding  printed  word.  But  the  evidence 
does  throw  some  light  on  the  problem  in  so  far  as  it  eliminates 
very  definitely  two  lines  of  explanation  which  have  been  thought 
possible.  First,  the  phenomenon  does  not  spring  from  a  dif- 
ference in  the  amount  of  practice  which  the  two  functions 
have  had  in  the  past.  Second  the  process  of  reading  words  is 
not  involved  in  the  process  of  naming  colors  as  a  subsidiary 
function.  The  two  functions  do  not  overlap,  and  in  all 
probability  they  depend  upon  distinct  physiological  processes. 

1  A  very  similar  problem  has  been  attacked  with  the  chronoscope  by  Bourdon. 
"Sur  le  temps  necessair  pour  nommer  les  nombres,"  Rev.  Philos.,  Vol.  65,  1908,  p.  426. 
He  finds  that  the  time  required  to  perceive  and  name  a  number  of  points  of  light 
(not  exceeding  four)  is  only  slightly  greater  than  the  time  required  to  read  arabic 
numerals.  Accordingly  he  infers  that  the  process  of  perceiving  a  few  points  as  a 
number  is  as  simple  as  perceiving  the  symbol  of  the  number.  Apparent  conflicts 
between  this  observation  and  the  results  in  the  case  of  naming  colors  are  now  under 
investigation  in  this  laboratory. 


XIX.    THE  APPARENT  RATE  OF  LIGHT  SUCCES- 
SION AS  COMPARED  WITH  SOUND  SUCCESSION1 

BY  BERTHA  VON  DER  NIENBURG 

It  has  often  been  observed  that  we  perceive  a  duration 
marked  off  by  lights  as  shorter  than  an  identical  duration 
marked  off  by  sounds,  a  result  readily  explained  by  the 
presence  of  after-images  in  the  case  of  the  light  sensations. 
Preliminary  experiments  with  series  of  lights  and  of  sounds 
indicated,  however,  that  not  infrequently  the  light  rate  seemed 
slower  than  the  sound  rate.2  This  study  was  undertaken  to 
look  into  the  subject  more  thoroughly,  first  from  a  descrip- 
tive view  point  and  later  from  a  causal  point  of  view. 

The  experiments  were  conducted  during  the  period  from 
September,  1910,  to  May,  1911,  in  the  psychological  labora- 
tory of  the  University  of  California.  The  subjects  were 
taken  from  the  class  in  general  psychology;  their  number 
varied  for  the  several  parts  of  the  work. 

I.  In  the  first  group  of  experiments  the  light  succession 
and  the  sound  succession  were  of  equal  rapidity.  The  ap- 
paratus in  the  main  consisted  of  a  metronome  and  a  minature 
electric  light,  a  telegraph  sounder,  and  the  necessary  switches 
and  connections.  The  current  flowing  through  the  metro- 
nome, which  was  placed  in  a  distant  room  so  that  its  ticking 

1  From  the  Psychological  Laboratory  of  the  University  of  California. 
8  Experiments  were  tried  upon  a  class  in  psychology  at  the  University  of  California, 
a  sound-series  and  a  light  series  of  equal  rate  (240  a  minute)  being  given  to  all  the 
students  together,  who  thereupon  reported  their  independent  judgments  in  writing. 
In  a  first  experiment  the  class  was  left  in  ignorance  as  to  the  relative  rates  of  the 
two  series,  the  questions  being  in  the  form:  "Are  the  two  series  of  equal  rate?  If 
not,  which  is  faster?"  The  judgments  were; 

That  the  light-series  was  faster  (L.F.) 24 

That  the  two  series  were  equal  (E.) 55 

That  the  light-series  was  slower  (L.S.) 50 

A  fortnight  later  the  same  class  was  told  that  the  two  series  were  of  equal  rate, 
and  the  students  were  asked  to  tell  how  the  series  seemed  in  this  respect— wheth  er 
they  seemed  equal,  or,  if  not,  which  seemed  faster.  The  judgments  were, 

L.F.          41  E.  10.  L.S.  70. 

56 


LIGHT  AND  SOUND  SUCCESSION  57 

might  not  be  heard  by  the  subject,  could  be  sent  either  into 
the  telegraph  sounder,  thus  marking  off  the  intervals  by  sound, 
or  into  the  incandescent  electric  bulb,  when  the  duration  was 
marked  off  by  light.  The  entire  apparatus  was  enclosed  by 
screens,  so  that  no  light  could  reach  the  eye  save  indirectly 
through  a  small  aperture  (^  inch  in  diameter)  which  flashed 
the  light  upon  a  screen. 

The  subject,  who  was  seated  before  the  screen  upon  which 
the  flashes  appeared,  was  told  that  he  would  be  given  a  series 
of  taps  to  be  followed  by  a  series  of  flashes,  and  that  he  was 
to  compare  the  rate  with  which  the  taps  were  coming  and 
the  rate  with  which  the  flashes  appeared.  He  was  allowed  a 
trial  in  the  beginning  to  insure  a  perfect  understanding  of  the 
experiment. 

Eighteen  subjects,  ten  women  and  eight  men,  were  ex- 
perimented upon.  Each  subject  was  allowed  to  form  his 
judgments  in  whatever  manner  seemed  most  natural  to  him. 

Three  rates  were  used,  namely  61,  154,  and  183  impres- 
sions per  minute,  or  each  interval  was  approximatly  i", 
.43",  and  .32"  in  length.  The  series  were  arranged  according 
to  the  following  plan.  First,  30  taps  at  .43"  following  30 
flashes  at  the  same  rate  were  given,  and  the  judgment  was 
recorded.  This  was  repeated  until  10  judgments  had  been 
obtained.  The  order  was  then  reversed,  30  flashes  being 
given  first,  with  judgment.  Next  came  10  taps  followed  by 
10  flashes,  and  a  reversal;  and  20  taps  following  20  flashes, 
and  then  the  order  reversed.  This  procedure  was  then 
followed  for  the  other  two  rates. 

The  percentages  of  respective  judgments  for  the  eighteen 
people,  combining,  at  first,  all  rates,  lengths,  and  orders,  are 
as  follows: 

Fourteen  subjects  were  used  for  one  hour  only,  and  while 
60  judgments  from  each  was  the  aim,  yet  because  of  irregular- 
ities in  the  apparatus  and  in  the  subjects  themselves  the  judg- 
ments differed  in  number  from  30  to  100.  Four  other  subjects 
gave  four  hours  and  passed  from  180  to  230  judgments.  I  have 
grouped  these  subjects  into  three  groups:  those  passing  from 
30  to  50  judgments,  those  passing  from  60  to  100  judgments 


BERTHA   VON  DER  N I  EN  BURG 


'Light  faster*  'Light  equal  to  sound'  'Light  slower' 

37-5%  54-9%  7-6% 

NUMBER  AND  PERCENTAGE  OF  RESPECTIVE  JUDGMENTS  PER  INDIVIDUAL 


Subjects 

Total 
Number  of 
Judgment! 
Passed 

'Light  Faster' 
Judgment! 

'Light  and 
Sound  Equal' 
Judgments 

'Light  Slower' 
Judgments 

Number 

Per 
Cent. 

Number 

Per 
Cent. 

Number 

Per 

Cent. 

Men 
A                   

200 
30 
100 

230 
60 
40 
40 

2IO 
9IO 

ISI 

18 

48 
46 

25 
4 
19 
US 

426 

I5'5 

oo.o 
48.0 

2O.O 
41.7 
10.0 

47-5 
54-8 

44-7 
46.8 

49 
9 
50 
184 
28 
36 
17 
79 

452 

24-5 
30.0 
50.0 
80.0 
46.7 
90.0 
42.| 
37-6 

50.2 

497 

3 

2 

7 

J 

32 

10 
II.7 
IO 

7^6 

5-2 

3-S 

B                   

E                 

L               ;  

N           

p           

s    

T  

Sub-totals    and    average    per 
cents 

Percentage    of   sum    of   each 
class  of  judgments,  of  total 
judgments  

NUMBER  AND  PERCENTAGE  OF  RESPECTIVE  JUDGMENTS  PER  INDIVIDUAL 


Subjects 

Total 
Number  of 
Judgments 
Passed 

'Light  Faster' 
Judgments 

'Light  and 
Sound  Equal' 
Judgments 

'Light  Slower' 
Judgments 

Number 

Per 
Cent. 

Number 

Per 
Cent. 

Number 

Per 
Cent. 

Women 
C     .            ... 

£ 

180 
60 

£ 
£ 

80 
50 

690 
i,  600 

14 

32 
2 

25 
10 
12 
H 

1 

23 
I76 

602 

3S-o 

53-3 
I.I 
41.7 

25.0 
IS.O 
35-0 
63.3 

46.0 
32.3 

25-5 
38.5 

37-6 

26 
27 
178 
27 

23 
67 

IS 
I 

74 
27 

465 
917 

65.0 

45-o 
98.9 

45-0 
57-5 
83.8 

37-5 
i-7 
92.5 
S4-o 

58.1 

67.4 
S4-i 

57-3 

I 

8 

7 
i 
ii 

21 

49 

81 

1-7 

13-3 
17.5 

i-3 

27-S 
35-o 

9-6 

7-1 
7-4 

S-i 

D  

F  

G  

H  

/  

K 

M 

O... 

R...     . 

Sub-totals    and    average    per 
cents  

Percentage   of  each   class   of 
judgments,   of   total   judg- 
ments   

Grand  totals  and  average  per 
cents  for  all  18  observers  .  . 
Percentage   of   sum    of   each 
class  of  judgments,  of  total 
judgments  

and  those  passing  from  180  to  230  judgments  and  giving  equal 
weight  to  each  individual's  results  we  have  the  following 
table: 


LIGHT  AND  SOUND  SUCCESSION  59 


Judgments 

No.  of  Obserrers 

L.  F. 

E. 

L.S. 

30  to  50 
60  to  100 
180  to  230 

7 
7 

4 

*& 

36.46% 

53-8% 
52.08% 

61.6% 

9-3% 
9-28% 
1-94% 

It  will  be  noticed  that  there  is  very  little  difference  in  the 
results  of  the  first  two  groups.  The  difference  in  the  results 
in  the  third  groups  I  judge  to  be  due  to  the  personnel  of  the 
group.  I  think  that  from  these  figures  I  may  conclude  that 
the  number  of  judgments  does  not  noticeably  affect  the  final 
results  and  that  it  is  therefore  not  distorting  the  facts  to 
throw  these  individuals  together. 

With  two  exceptions  each  individual  varied  to  a  large 
extent  in  his  successive  estimations.  With  no  person  was 
the  sound  declared  faster  for  a  majority  of  the  judgments, 
while  in  the  case  of  seven  persons  it  was  never  considered 
faster  at  all.  In  the  case  of  twelve  of  the  observers,  the 
greater  number  (the  'plurality')  of  their  judgments  were  of 
equality,  and  with  the  remaining  six  observers,  the  light 
rate  of  succession  was  deemed  faster  than  the  sound  rate. 

II.  To  obtain  a  numerical  evaluation  of  the  differences 
in  the  apparent  ratings  of  the  succession  of  these  series,  the 
apparatus  was  now  arranged  so  that  the  rate  of  the  flashes 
could  be  altered  at  will.  While  the  sounder  was  still  operated 
through  the  metronome,  the  electric  bulb  was  put  on  another 
circuit.  The  physical  light  was  now  continuous;  but  by 
revolving  on  a  kymograph  before  it  a  wheel  from  whose 
circumference  eighteen  acute  angled  notches  were  cut,  the 
effect  of  flashes  was  given  to  the  subject  who  saw  the  light 
through  a  small  aperture  in  a  black  screen.  A  piece  of 
ground  glass,  placed  directly  at  the  back  of  the  wheel,  served 
to  make  the  light  more  distinct.  By  means  of  the  kymo- 
graph, the  rate  of  succession  could  be  varied  at  will.  In 
this  part  of  the  work  the  duration  of  each  flash  of  light  was 
the  same  as  that  of  the  dark  interval  which  followed  it.  The 
sound  rate  remained  constant,  that,  is  154  beats  per  minute. 
The  light  rate  was  varied,  by  steps  of  eight  beats  per  minute, 
between  the  limits  of  the  variable  judgments,  which  proved 
to  be  between  no  and  166  beats  per  minute.  Twenty  clicks 


6o 


BERTHA  VON  DER  N I  EN  BURG 


followed  by  twenty  flashes  were  given  throughout  this  group. 
The  light  succession  first  compared  was  at  a  rate  of  no  a 
minute,  then  126,  and  so  to  142,  158,  118,  134,  150,  and  166. 
Ten  judgments  for  each  series  were  obtained.  Five  subjects 
designated  alphabetically  in  the  following  table,  were  used, 
the  first  four  persons  having  been  subjects  in  the  previous 
work. 

The  approximate  points  at  which  the  succession  of  lights 
were  judged  to  be  of  equal  rapidity  with  the  I54~beat-per- 
minute  sound-rate  were: 


Person 

A.. 


C. 
D. 
E. 


134 

138 

138 

126 

146 


In  each  of  these  cases,  therefore,  the  light  rate  was  esti- 
mated to  be  (relatively  to  the  sounds)  faster  than  it  really  was. 
In  the  former  part  of  the  experiment,  where  equal  rates  of 
succession  were  judged,  the  results  for  such  of  these  subjects 
as  there  acted  as  observers  read  for  the  154-impressions-a- 
second  rate: 


L.  F.i 

E.i 

L.S.i 

A.. 

oc% 

c% 

B 

2  ?% 

07  rOf 

c 

5% 

QC% 

P  

17-5% 

V.5  fO 

62.5% 

20% 

Where  the  two  series  to  be  compared  were  kept  equal,  the 
judgments  do  not  show  the  same  uniformity  as  in  those 
series  where  the  rate  of  the  light  succession  was  varied. 

In  the  entire  group  of  experiments  it  was  evident  that 
there  were  variations  in  the  judgments  of  the  same  individual 
from  day  to  day,  and  from  individual  to  individual. 

III.  A.  Attention  was  now  given  to  the  various  factors 
that  might  cause  some  of  the  variations  in  the  judgments 
passed  upon  the  equal  rate  of  succession.  The  influence  of 

1  These  abbreviations  stand  here  and  elsewhere  for  judgments  'Light  Faster 
than  Sound,'  'Light  Equal  to  Sound,'  and  'Light  Slower  than  Sound.' 


LIGHT  AND  SOUND  SIUCCESSON 


61 


the  rate  itself  was  first  observed.  Three  rates  were  used, 
183,  154,  and  61  beats  per  minute;  i.  e.,  each  double  phase 
was  approximately  0.3 2",  0.43",  and  i"  long.  From  20  to 
1 20  judgments  were  given  for  each  rate  of  six  subjects.  The 
percentage  of  the  respective  judgments  for  all  are  given  in 
the  accompanying  table: 

NUMBER  AND  PER  CENT.  OF  JUDGMENTS  FOR  VARYING  RATES 


Rates:               61 

154 

183 

Sub- 

Judgments of 

ject 

L.  F. 

E. 

L.  S. 

L.  F. 

E. 

L.  S. 

L.  F. 

E. 

L.S. 

No. 

* 

No. 

% 

No. 

i 

No. 

i 

No. 

% 

No. 

i 

No. 

i 

No. 

* 

No. 

t 

A.. 

57 

71-3 

23 

28.8 

- 

— 

38 

95 

2 

5 

_ 

— 

56 

70 

24 

30 

_ 

— 

E  .. 

7 

35 

II 

£5 

2 

10 

32 

53-3 

28 

46.7 

— 

— 

9 

45 

II 

55 

— 

— 

F... 

2O 

IOO 

- 

— 

I 

2-5 

39 

97-5 

- 

— 

I 

0.8 

119 

99.2 

- 

— 

1... 

— 

— 

19 

55 

I 

5 

9 

22.5 

3i 

77-5 

- 

— 

3 

15 

17 

85 

- 

— 

L... 

— 

— 

40 

IOO 

— 

— 

3 

5 

57 

95 

— 

— 

43 

3S-8 

77 

64.2 

— 

— 

T  .. 

26 

37-1 

41 

^8.6 

3 

4-3 

7 

17-5 

25 

62.  <; 

8 

20 

82 

82 

13 

13 

5 

5 

90 

23-9 

154 

72.9 

6 

3-2 

90 

32-6 

182 

64.0 

8 

3-3 

194 

41-5 

261 

57-7 

5 

.8 

These  results  would  indicate  that  the  light  appears  re- 
latively faster  as  the  rate  of  succession  is  increased.  In- 
dividual differences,  however,  exist. 

B.  The  influence  of  different  lengths  of  the  series  was  now 
tested.  Three  series,  of  30  beats,  and  20  beats,  and  10  beats, 
respectively,  were  used.  The  percentages  are  made  up  of 
from  20  to  1 20  judgments  by  eight  individuals  for  each  series. 

INDIVIDUAL  TABULATION  OF  PERCENTAGE  OF  RESPECTIVE  JUDGMENTS  FOR  SERIES 

OF  VARYING  LENGTHS. 


Length  of  Series 

10 

20 

30 

Sub- 
ject 

Judgments  of 

L.  F. 

E. 

L.S. 

L.  F. 

E. 

L.S. 

L.  F. 

E. 

L.  S. 

No. 

* 

No. 

* 

No. 

i 

No. 

i 

No. 

i 

No. 

$ 

No. 

* 

No. 

* 

No. 

i 

A  .. 

93 

77-5 

27 

22.5 

- 

— 

46 

76.7 

H 

23-3 

— 

— 

12 

60 

8 

40 

_ 



t  ... 

— 

— 

40 

IOO 

- 

— 

I 

i 

99 

99 

— 

— 

I 

2-5 

39 

97-5 

- 

— 

G  .  . 

5 

25 

II 

50 

4 

20 

II 

55 

9 

45 

— 

— 

13 

65 

7 

35 

- 

— 

L.  . 

3 

75 

36 

90 

I 

2-5 

6 

30 

H 

70 

— 

— 

3 

15 

17 

85 

— 

— 

H  .. 

7 

8.75 

73 

91.2 

- 

24 

24 

76 

76 

— 

— 

15 

37-S 

2S 

62.  S 

- 

— 

A  .. 

6 

30 

12 

60 

2 

IO 

13 

65 

7 

35 

— 

— 

12 

60 

7 

35 

I 

5 

O  .. 

i 

2.5 

39 

97-5 

— 



3 

30 

7 

70 

— 

— 

35 

87.5 

5 

12.  S 

— 

T  .. 

40 

44.4 

48 

53-3 

2 

2.2 

58 

58 

28 

28 

H 

H 

17 

85 

3 

15 

- 

— 

24-5 

71.2 

4-3 

42.4 

55-8 

1.8 

51-6 

47.8 

.6 

62  BERTHA  VON  DER  NIENBURG 

There  is  here  a  tendency  for  the  apparent  rate  of  light 
succession  to  increase  as  the  series  is  lengthened.  This  is 
not  only  manifested  in  the  percentages  of  the  eight  subjects 
together,  but  in  those  for  each  individual  save  one.  All 
subjects  agreed  that  the  thirty-beat  series  was  unnecessarily 
long.  Those  persons  who  formed  their  judgments  immedi- 
ately felt  that  the  ten-beat  series  allowed  sufficient  time  to 
make  the  judgments,  while  those  who  formed  no  estimation 
until  the  final  beat  preferred  the  twenty-beat  series. 

C.  Since  it  was  considered  by  many  of  the  observers  to 
be  much  easier  to  form  judgments  when  the  sound  succession 
was  given  first,  the  effect  of  the  order  of  the  light  and  sound 
successions  was  next  considered.     The  same  eighteen  subjects 
were  experimented  upon  with  the  following  results: 

Per  Cent.  Distribution  of  Judgments 
Sound-Light  Light-Sound 

L.  F.  E.  L.  S.  L.  F.  E.  L.  S. 

38  51  ii  42  52  6 

These  combined  results  indicate  a  slight  increase  in  the 
Might  faster'  judgments  when  the  order  is  reversed  from 
sound-light  to  light-sound.  But  taking  into  account  the 
variation  in  individual  cases,  we  may  conclude  that  while 
the  order  may  increase  the  ease  with  which  the  judgments 
can  be  made,  its  effect  upon  the  quality  of  the  judgment  is 
slight. 

D.  All  the  observers  felt  that  it  was  easier  to  form  an  idea 
of  the  sound  intervals  than  of  the  light  intervals,  and  gave  as 
their  reason,  that  in  the  latter  the  flashes  disappeared  gradu- 
ally, instead  of  sharply  as  the  sound  did.     By  raising  and 
lowering  the  light  before  the  notched   wheel   described  on 
page  59  the  ratio  of  light  to  darkness  could  be  changed.     The 
effect  of  this  change  upon  the  rate  at  which  the  light  suc- 
cession was  judged  to  be  of  the  same  rapidity  as  the  sound 
succession  was  studied  in  experiments  upon  four  persons. 

First  of  all,  with  the  duration  of  the  flash  equal  to  that  of 
the  dark  phase,  and  with  the  sound-series  preceding  at  a  rate 
of  154  beats  per  minute— there  was  found  for  each  individual 
the  rate  at  which  the  light-series  seemed  equal  to  that  of  the 


LIGHT  AND  SOUND  SUCCESSION 


sound  series.  While  no  point  was  considered  the  ' equality' 
consistently  by  any  person,  yet  one  rate  was  judged  to  be  so 
more  often  than  others.  This  rate  I  shall  designate  as  the 
*  point  of  apparent  equality.'  The  ratio  of  the  light  to  the 
total  cycle  of  light-phase  plus  dark-phase  was  then  increased 
to  75  per  cent.,  and  ten  judgments  made;  and  then  decreased 
to  25  per  cent.,  and  ten  judgments  recorded;  and  then  back 
to  50  per  cent.  The  order  of  these  shifts  from  one  ratio  to 
another  was  inconstant,  so  that  sometimes  we  would  go  from 
50  per  cent,  to  25  per  cent,  and  then  to  75  per  cent.,  or  again 
from  25  per  cent,  through  50  per  cent,  to  75  per  cent.,  and  so 
on.  For  the  various  persons  the  results  were  as  follows : 


Sub- 
ject 

Apparent 
Equality  Point 
of  Light  Rate 
When  Sound 
Rate  Equals  1541 

Ratio  of  Light  to  Light-plus-Dark 

25  Per  Cent. 

50  Per  Cent. 

75  Per  Cent. 

L.  F. 

E. 

L.  S. 

L.  F. 

E. 

L.  S. 

L.  F. 

E. 

L.  S. 

A  .. 
B  .. 
C.. 
£>.. 

128 
148 
134 
ISO 

76 
24 

76 

18 
24 
24 
24 

6(i) 
72(d) 
72(d) 
-(i) 

8.0 

16 

2 

16 

78 
78 
76 

78 

3 

22 

6 

20 

60 
22 

58 

20 
38 

22(d)2 

ioo(d) 

20(i) 

4o(d) 

A  shows  a  slight  tendency  to  increase  his  Might  faster'  and 
'light  slower'  judgments  at  the  expense  of  the  equality 
judgments  in  the  75  per  cent,  ratio,  while  in  the  25  per  cent, 
ratio  there  is  a  marked  increase  in  the  'light  faster'  judg- 
ments. B  shows  a  great  increase  of  judgments  'light 
slower'  at  the  75  per  cent,  ratio,  and  nearly  as  great  a  one  for 
the  25  per  cent.  C  shows  a  like  tendency  for  the  25  per  cent, 
ratio,  but  exhibits  just  the  opposite  tendency  for  the  75  per 
cent,  ratio.  D  shows  an  increase  of  'light  slower'  judgments 
for  75  per  cent,  and  of  'light  faster'  judgments  at  25  per  cent. 
In  three  cases,  therefore,  and  contrary  to  expectation  (since 
the  interval  between  flashes  is  now  decreased)  the  75  per  cent, 
ratio  of  light  to  darkness  decreases  the  apparent  rapidity  of 
the  light,  and  the  25  per  cent,  ratio  increases  it. 

E.  After  a  month's  time,  the  same  observers  together  with 
a  new  one,  E,  were  used  as  subjects  to  see  whether  the  ten- 

1  Here  and  in  the  following  table,  *d'  indicates  decrease  in  the  apparent  rate,  'i' 
increase  and  'N'  no  change. 

*  Determined  afresh  for  this  portion  of  the  experiment. 


64 


BERTHA  VON  DER  N I  EN  BURG 


dencies  displayed  above  would  exist  when  the  gradation 
method  was  used.  The  work  was  conducted  in  the  manner 
described  above;1  that  is,  with  the  sound  rate  at  154,  the  light 
rate  was  varied  by  steps  of  eight  beats  per  minute  from  no 
beats  to  166  beats.  This  was  done  for  each  of  the  three  ratios 
of  light  to  dark,  ten  estimations  being  recorded  for  each  rate 
compared.  The  approximate  points  where  the  light  rate  was 
judged  equal  to  the  sound  rate  were: 

RATE  OF  LIGHTS  PER  MINUTE  WHICH  SEEMED  EQUAL  TO  154  SOUNDS  PER  MINUTE 


Subjects 

Ratio  of  Light  to  L.  +  D. 
25  Per  Cent. 

Ratio  of  Light  to  L.  -f  D. 
50  Per  Cent. 

Ratio  of  Light  to  L.  +  D. 
75  Per  Cent. 

A.. 

134  (N)  (i)2 

134 

132  (I?)  (d?) 

B 

130  (I)    (d) 

138 

118  (I)    (d) 

c 

136  (I?)  (d) 

138 

126  (I)     (i) 

D 

130  (D)  (i) 

s 

126 

137  (D)  (d) 

E  

142  (D 

146 

136  (D 

^'s  point  where  the  light  rate  seems  to  equal  the  154 
sound  rate  is  somewhat  higher  than  it  was  in  the  earlier  group 
of  experiments;  he  no  longer  exhibits  the  same  tendency  as 
before,  that  is,  to  regard  the  light  rate  as  faster  for  the  25  per 
cent,  ratio  than  for  the  other  ratios.  5's  equality  point  is  the 
same  as  before,  but  now  the  light  succession  appears  to  come 
much  faster  for  both  the  75  per  cent,  and  25  per  cent,  ratios, 
which  is  just  the  opposite  of  the  earlier  results.  C's  equality 
point  now  is  somewhat  lighter.  His  judgments  are  consistent 
for  the  75  per  cent,  ratio  with  those  of  a  month  earlier,  but  not 
for  the  25  per  cent,  ratio.  Z)'s  point  of  equality  has  fallen 
fourteen  beats  per  minute,  and  instead  of  an  increased  ap- 
parent light  rate  for  25  per  cent,  as  at  first,  it  is  decreased. 
To  the  new  subject,  the  apparent  light  rate  is  increased  by  the 
greater  ratio  of  light,  and  to  a  less  degree  is  increased  by  the 
smaller  ratio. 

In  most  cases,  then,  the  75  per  cent,  ratio  has  apparently 
quickened  the  light  rate,  and  the  25  per  cent,  ratio  has  also 
quickened  it.  In  the  previous  group  of  experiments,  the 
apparent  rate  was  increased  or  decreased  for  the  25  per  cent. 

1  See  page  60. 

JThe  lower-case  letters  indicate,  'increase'  and  'decrease'  respectively,  in  the 
earlier  groups  (see  p.  (63)). 


LIGHT  AND  SOUND  SUCCESSION  65 

and  the  75  per  cent,  ratio  about  indifferently.  The  conclusion 
seems  warranted  that  the  judgment  of  the  rate  is  not  based 
greatly  upon  the  interval  between  impressions.  For  were  the 
apparently  greater  rapidity  of  the  light-succession  due  to  its 
blur  and  after-image  filling  in  the  interval  between  im- 
pressions, and  so  making  them  appear  to  come  closer  together, 
then  the  75  per  cent,  ratio  of  light  to  darkness  should  greatly 
increase  the  rate  of  the  light  succession,  and  the  25  per  cent, 
ratio  should  decrease  its  apparent  rate  in  somewhat  the.  same 
degree.  This,  however,  did  not  happen  in  the  above  experi- 
ments. 

F.  Throughout  the  previous  work,  a  record  had  been 
kept  of  the  natural  and  spontaneous  manner  in  which  the 
subjects  formed  their  judgments.  Four  different  ways  pre- 
dominated. Some  said  that  they  got  an  idea  of  the  suc- 
cession of  the  beats  in  the  first  series  given,  and  noticed  the 
likeness  or  difference  in  the  rate  of  the  second  series  to  it. 
This  mode  will  be  designated  by  the  term  "  general  impres- 
sion." Others  seem  to  have  judged  by  various  synchronous 
muscular  rhythms,  of  which  I  shall  count  as  the  second 
group  those  in  whom  this  rhythm  was  less  voluntary  and 
conventional,  occurring,  e.  g.,  in  the  forehead,  or  in  the  back 
of  the  head.  In  a  third  group  are  placed  those  who  counted; 
and  in  a  fourth  group,  those  who  tapped. 

Dividing  twelve  of  the  people  used  in  the  first  part  of  the 
work  according  to  their  mode  of  making  a  judgment,  three 
fall  in  Group  I.,  three  in  Group  II.,  four  in  group  III.,  and  two 
in  Group  IV.  The  percentage  of  respective  judgments  for 
the  varying  groups  is  as  follows,  when  light  rate  and  sound 
rate  were  physically  equal  (154  per  sec.). 


Group 

L.  F. 

E. 

L.  S. 

I.  . 

73  6 

2C  6 

8 

II  

20  o 

zyu 

70  8 

92 

Ill 

21  O 

R   T 

IV  

zi.y 
38.75 

51-25 

IO.O 

These  figures  indicate  that  those  who  simply  get  an 
'impression'  give  nearly  three  fourths  of  their  judgments  as 
'light  faster,'  while  those  judging  by  muscular  rhythm  and 


66  BERTHA  VON  DER  N I  EN  BURG 

those  who  counted  give  as  such  less  than  a  quarter  of  their 
judgments.  In  the  latter  two  groups  the  number  of ' equality ' 
judgments  is  increased  to  more  than  one  half  the  entire 
number,  while  the  Might  slower7  judgments  are  greater  than 
in  the  first  and  the  fourth  group. 

G.  Ten  subjects  who  had  never  been  experimented  upon 
previously  were  taken  to  make  a  further  study  of  the  direct 
effect  upon  the  judgments  themselves  of  deliberately  follow- 
ing these  different  ways  of  forming  their  judgments.  They 
were  first  given  the  sound-light  series  with  the  eight  light- 
rates  and  the  154-beat-per-minute  sound-rate.  One  judgment 
was  passed  upon  each  series.  Then  ten  judgments  were 
made  in  the  series  in  which  the  sound  and  light  successions 
were  both  154  per  minute;  the  first  procedure  of  one  judgment 
on  each  series  with  a  varying  light  rate  was  again  gone 
through.  Nothing  was  said  as  to  ways  or  means  of  judging, 
so  that  each  subject  employed  the  method  most  natural  to 
him.  The  above  process  was  then  repeated  twice  with  other 
definite  methods  of  forming  the  judgments  now  imposed. 
If  the  original  method  used  had  been  by  'general  impression,' 
the  person  was  asked  to  count  for  one  series,  and  to  beat  for 
the  next.  Where  the  'general  impression'  method  had  to  be 
imposed,  to  be  certain  that  there  would  be  no  muscular 
rhythm,  the  subjects  were  asked  to  say  and  repeat,  'There 
is  a  black  cat,'  aloud  as  fast  as  possible.  Great  care  was  taken 
that  this  was  in  no  way  made  to  fit  in  with  the  rhythm  of  either 
series.  This  procedure  after  it  had  been  tried  one  or  two 
times  by  the  subject  in  no  way  hindered  the  person  from  giving 
attention  to  the  series  and  did  stop  any  involuntary  vocal 
synchronisms,  so  that  the  person  would  be  judging  by  his 
impression  alone. 

When  left  to  do  as  they  would,  six  of  the  subjects  beat, 
two  counted,  and  two  judged  by  their  impression  of  succession. 
Throughout  this  part  of  the  work  it  was  noticed  that  while 
each  individual  may  attempt  to  judge  in  the  same  manner, 
many  variations  still  remain.  For  instance,  in  beating,  a 
person  may  move  his  whole  arm,  his  hand  entire,  or  use  his 
finger  only  slightly.  He  may  synchronize  the  sound  and 


LIGHT  AND  SOUND  SUCCESSION  67 

keep  beating  that  rate  throughout  the  light  series,  forming 
his  judgments  of  the  latter  by  the  way  its  flashes  fall  in  with 
his  beating,  or  he  may  change  his  tapping  as  the  flashes  change, 
or  he  may  cease  to  tap  entirely  for  the  light.  He  may  tap  a 
decided  rhythm,  he  may  synchronize  well  for  the  sound  and 
not  for  the  light,  or  he  may  not  be  able  to  do  so  for  either. 
In  cases  where  the  tapping  changed  with  the  oncoming  of 
the  flashes,  it  was  noticed  that  in  some  cases  this  change  in 
the  tapping  would  be  reflected  in  the  answer,  while  in  other 
cases  the  difference  in  tapping  was  no  indication  of  what  the 
judgment  would  be.  Similar  differences  were  noticed  in  the 
counting.  If  a  person  tapped  with  marked  irregularity,  his 
counting  was  of  the  same  sort.  With  all  this  variety  in  these 
two  aids  to  the  formation  of  time  judgments  it  could  hardly  be 
expected  that  harmonious  results  for  different  individuals 
who  are  beating  and  then  counting  could  be  obtained.  The 
average  percentages  of  judgments  by  the  three  modes  em- 
ployed are,  however,  as  follows: 

LIGHT  SERIES  AND  SOUND  SERIES  AT  EQUAL  RATE  (154  PER  MINUTE) 

General  Impression  Counting  Tapping 

L.  F.         E.  L.  S.  L.  F.       E.         L.  S.  L.  F.  E.  L.  S. 

52.5%    32%    iS-5%  59%    29%    12%  55.5%    28%     16.5% 

The  later  tables  that  give  the  judgments  in  more  detail 
show  the  great  difference  in  the  different  individuals.  The 
number  of  'light  slower'  judgments  seems  marked  when  we 
remember  that  in  the  first  group  of  persons  examined  7.6  was 
the  average  per  cent,  of  such  judgments  given.  The  apparent 
equality  points  for  these  observers  were,  as  found  by  the 
gradation  method: 

General  Impression  Counting  Tapping 

I4I.8  142  146.6 

As  elsewhere,  the  judgments  by  this  method  do  not  coin- 
cide with  those  made  on  the  equal  rates.  In  the  six  cases 
where  the  natural  method  was  to  tap,  the  average  percentages 
indicate  a  falling  off  of  'light  faster'  judgments  for  the  im- 
posed methods  with  an  approximate  increase  of  50  per  cent, 
in  the  'light  slower'  judgments  when  judging  by  the  General 
Impression  method.  Results: 


68 


BERTHA  FON  DER  NIENBURG 


EFFECT  OF  DEPARTING  FROM  NATURAL  METHOD 


Subjects 

Natural  Method 

Imposed  Methods 

Tapping 

General  Impression                        Counting 

Judgments  of 

L.  F. 

E. 

L.  S. 

L.  F. 

E. 

L.  S. 

L.  F. 

E. 

L.S. 

I 

2 

3 
4 

100% 
60 
20 

25 
90 
80 

l\ 

60 
IO 

20 

5 
15 
15 

80% 
50 

1° 
60 

80 

10 
40 
60 
40 

40 
20 

10 
10 
40 
10 

100% 
60 
20 

50 
60 
70 

40 
80 

50 
40 
2O 

IO 

Average  Per  Cent. 

62.5 

31.67 

5.83 

53-33 

35 

11.67 

60 

38.33 

1.67 

Counting 

General  Impression 

Tapping 

8 

80% 
30 

10 
30 

10 

40 

30 
80 

30% 

20 

40 

50% 
50 

20 
30 

30 
20 

Average  Per  Cent. 

55-0 

20.0 

25.0 

55-o 

25-0 

20.0 

50.0 

25.0 

25.0% 

General  Impression 

Tapping 

Counting 

9 

10 

50% 
65 

40 

10 

35 

60% 
20 

40 

80 

80% 
40 

20 

60 

57-5 

20.0 

22.5 

40.0 

20.0 

40.0 

60.0 

IO.O 

30 

Those  who  naturally  counted  show  individually  a  consider- 
able change  in  result  under  the  other  methods,  though  when 
these  results  are  combined  there  is  but  a  slight  tendency  to 
quicken  the  light  during  the  general  impression  and  to  quicken 
the  sound  while  tapping. 

When  counting  and  tapping  are  the  imposed  methods  the 
'light  slower'  judgments  are  markedly  increased  with  one  of 
the  subjects. 

In  only  four  cases  does  the  natural  method  tend  to  give  a 
greater  number  of  equality  judgments. 

Two  individual  records  in  this  group  deserve  special 
attention.  Instead  of  judging  of  the  succession  of  beats  as 
did  the  other  subjects,  one  of  these  judged  of  the  succession 
of  the  intervals,  so  that  in  tapping  and  counting,  instead  of 
matching  his  beat  to  that  of  the  metronome,  he  counted  and 
tapped  after  its  beat.  His  results  are  as  follows : 

Judgments  for  20  S-L,  with  both  sound  and  light  at  the 
equal  rate  of  154  per  minute, 


General  Impression 

65%L.F.    35%L.S. 


Counting 

40%L.F.    60%  L.S. 


Tapping 
20%  L.F.      80%  L.S. 


LIGHT  AND  SOUND  SUCCESSION  69 

Equality  point  when  sound  was  at  154,  and  the  light  rate 
varied  (gradation  method) : 

General  Impression  Counting  Tapping 

154  138  154 

A  contradiction  in  the  results  obtained  by  the  two  methods 
thus  is  evident.  While  this  subject's  original  method  was 
that  of  the  general  impression,  he  said  after  he  had  tried  the 
others,  that  tapping  was  by  far  the  surest. 

The  other  person  had  a  noticeably  high  ' equality  point'; 
in  fact  he  was  the  only  person  of  the  twenty-nine  subjects 
experimented  upon  who  ever  gave  as  an  apparently  identical 
rate,  a  higher  rate  of  light  succession  than  of  sound  succession. 
His  results  read: 

General  Impression   ,    Counting         Tapping 
Equality    point    by    gradation    method     (16 

judgments  each) 160  150  154 

F.  E.  S.          F.  E.  S.          F.  E.  S. 
Distribution  of  judgments  per  cent,  when  light- 
rate  =  sound-rate  (154).     (10  judgments 
each) —  60  40         20  80  —         20  65  15 

From  these  various  modifications  of  the  experiment  we 
may  perhaps  be  justified  in  drawing  the  following  conclusions. 

1.  The  commonly  accepted  statement  that  of  equal  times 
marked  off  by  light  and  sounds  the  light-limited  durations 
seem  shorter  than  the  sound-limited  is  by  no  means  univer- 
sally true,  when  applied  to  the  apparent  rate  of  succession  of 
series  of  light  and  of  sound  impressions. 

The  experience  that  the  light  succession  is  less  rapid  than 
the  sound  succession  comes  not  infrequently,  and  with  some 
observers  comes  indeed  more  frequently  than  does  the  op- 
posite experience,  that  the  light  succession  is  more  rapid. 

2.  With  persons  who  are  practiced  the  impression  that  of 
two  equal  rates  the  light  rate  is  the  slower  does  not  appear  to 
be  influenced  directly  by  the  amount  of  such  practice.     But 
when  there  is  no  practice  at  all,  as  in  the  class  experiments,  a 
greater  number  of  persons  take  the  light  series  to  be  slower 
than  take  it  to  be  faster. 

3.  The  apparent  difference  of  rate  between  light  succession 


70  BERTHA  VON  DER  N I  EN  BURG 

and  sound  succession  does  not  seem  to  be  directly  connected 
with  the  persistence  of  the  light  effect  upon  the  retina,  which 
makes  the  blank  lapse  of  time  between  the  impressions  less 
in  the  case  of  light  than  in  that  of  sound.  For  in  the  first 
place,  this  could  not  explain  those  not  infrequent  cases  where 
the  light  rate  seems  slower;  and,  secondly,  the  effect  of  arti- 
ficially varying  this  blank  lapse  without  changing  the  rate 
itself  affects  in  no  simple  and  direct  way  the  apparent  rate 
of  the  impressions.  The  change  of  the  blank  interval  to  an 
interval  less  than  has  become  familiar  seems  more  frequently 
to  have  an  effect  similar  to  a  change  in  the  opposite  direction 
(i.  e.,  an  increase  of  the  blank  interval);  although  different 
persons  respond  differently  to  this  experiment,  and  differently 
at  different  times. 

4.  The  higher  the  rate  of  the  two  kinds  of  succession  here 
compared,  the  more  pronounced  becomes,  with  most  obser- 
vers, the  illusion  that  the  light  series  is  the  more  rapid. 

5.  The  longer  the  series  of  impressions  to  be  compared,  the 
more  pronounced  is  the  illusion  that  the  light  series  is  the 
more  rapid. 

6.  The  order  in  which  the  two  series  is  given  affects  the 
result:  the  impression  of  greater  rapidity  in  the  light  series 
comes,  with  most  observers,  more  frequently  when  the  light 
series  precedes  the  sound  series. 

7.  The  method  of  forming  the  judgment  of  the  relative 
speed  of  these  successions  differs  greatly  with  different  ob- 
servers.    Those  who  naturally  incline  to  assist  their  judg- 
ments by  counting  or  by  noticing  some  hidden  organic  rhythm, 
in  general  have  less  frequently  the  sense  of  greater  speed  in 
the   light   series   than   have   those   who   depend   upon   their 
'general  impression'  (whatever  that  may  mean)  or  upon  an 
overt  tapping  by  hand  or  finger.     Yet  the  illusion  of  greater 
speed  in  the  light  does  not  seem  to  depend  upon  the  presence 
or  absence  of  mental  aid  from  any  noticeable  organic  rhythm, 
whether  voluntary  or  involuntary. 


XX.    A  MEMORY  TEST  WITH  SCHOOL  CHILDREN1 

BY  ARTHUR  H.  CHAMBERLAIN 

THE  PROBLEM  STATED 

With  a  view  to  determining  the  power  of  recall  in  school 
children,  a  series  of  tests  were  made.  It  was  sought  to  ascer- 
tain the  effect  upon  the  power  to  recall  when: 

1.  A  number  of  objects  are  displayed  (a)  singly;  (b)  three 
together. 

2.  The  objects  chosen  interest,  we  might  suppose,  par- 
ticularly (a)  the  boy's  mind;  (b)  the  girl's  mind. 

3.  The  subjects  tested  are  of  different  school  grades. 

4.  The  subjects  tested  are  of  different  sex. 

OBJECTS  CHOSEN 

Fifteen  objects  were  selected  as  follows:  pocket  knife,  roll 
of  string,  marble,  watch,  key,  flat-iron,  threaded  needle, 
thimble,  scissors,  doll,  pencil,  notebook,  two-cent  stamp, 
five-cent  nickel,  and  match. 

These  objects  fall  into  three  groups:  First,  those  that 
interest  particularly  the  boys  and  are  handled  by  them  in 
their  daily  routine.  These  are  the  first  five  objects  listed. 
Second,  those  that  might  be  expected  to  interest  the  girls. 
These  are  the  second  five  objects  named.  Third,  those  that 
are  of  equal  interest  to  both  sexes.  These  consitute  the  final 
five  objects.  All  of  the  objects  are  found  constantly  in  the 
child's  environment.  Choice  was  made  of  objects  that  were 
not  too  greatly  different  in  size. 

THE  SUBJECTS 

The  subjects  were  chosen  from  the  third,  fifth  and  eighth 
grades,  sixty  from  each  grade,  one  hundred  eighty  pupils, 
all  told.  They  were  equally  divided,  thirty  boys  and  thirty 
girls  from  each  grade.  They  represented  several  different 

1  From  the  Psychological  Laboratory  of  the  University  of  California. 

71 


72  ARTHUR  H.  CHAMBERLAIN 

schools,  in  various  sections  of  the  city  where  the  tests  were 

made. 

APPARATUS  USED 

The  apparatus  for  the  tests  was  simple:  A  circular  disc 
of  wood,  one-half  inch  thick  and  eighteen  inches  in  diameter 
served  as  a  stand  upon  which,  near  its  outer  edge,  the  objects 
were  arranged  at  equal  distances  apart.  A  second  disc  of  like 
thickness  and  twenty-four  inches  in  diameter,  had  an  opening 
whose  size  could  be  varied  as  desired.  The  larger  disc  was 
placed  four  inches  above  the  smaller,  which  rested  flat  upon  a 
desk  or  table.  The  upper  disc  was  held  in  its  horizontal 
position  and  made  to  revolve  over  the  lower  disc  as  a  wheel 
revolves  on  an  axle.  This  was  accomplished  by  means  of  a 
rectangular  block  having  either  end  cut  to  a  step-cylinder  and 
housed  or  shouldered  into  the  inner  faces  of  the  two  discs 
at  their  centers. 

ARRANGEMENT  OF  OBJECTS 

Those  five  objects  supposed  to  be  more  familiar  to  the  girls 
were  placed  in  sequence — the  threaded  needle,  flat-iron, 
thimble,  doll  and  scissors.  In  the  same  way  those  objects 
pertaining  chiefly  to  the  boys  were  arranged  in  sequence — 
marble,  knife,  watch,  key  and  roll  of  string. 

MODES  OF  DISPLAY 

During  the  tests  there  were  two  modes  of  display.  First, 
the  objects  were  shown  in  such  a  way  that,  at  all  times,  three 
were  visible,  while  as  each  new  object  entered  this  group,  one 
of  the  older  members  of  it  dropped  out.  Second,  they  were 
displayed  singly.  Any  one  subject  was  tested  with  only  one 
mode  of  display. 

METHOD  OF  PROCEDURE 

Each  subject  was  allowed  one  minute  for  observation  of 
the  fifteen  objects,  whatever  was  the  mode  of  display.  In 
the  first  test,  the  subject  was  placed  directly  in  front  of  the 
cut-out  sector  and,  as  the  upper  disc  revolved,  the  objects 
came  into  view,  three  at  a  time.  The  subject  moved  with 


MEMORY  TEST  73 

the  disc,  thus -keeping  directly  in  front  of  the  opening.  In 
the  second  test,  the  same  order  of  arrangement  was  main- 
tained, but  the  opening  in  the  disc  revealed  only  one  object 
at  a  time.  By  allowing  three  seconds  for  each  exposure,  with 
one  second  interval,  a  total  of  one  minute  was  given  as  in 
the  other  test. 

In  every  instance  note  was  made  of  the  object  at  which 
the  observation  was  begun.  The  immediate  recall  was 
tested  at  the  close  of  the  experiment  by  having  the  pupil 
name  all  the  objects  he  could  remember.  A  list  of  these 
objects  was  recorded  by  the  operator  in  the  order  in  which  the 
pupil  named  them.  The  subject  was  also  given  a  sheet  of 
paper  having  a  circle  described  upon  it  and  corresponding 
to  the  disc.  Upon  this  circle  he  was  asked  to  locate  the  objects 
in  the  order  in  which  they  were  placed  on  the  disc.  Any 
additions  to  the  list  of  objects  originally  recalled  were  placed 
to  the  observer's  credit.  Record  was  then  made  of  the  total 
number  of  objects  recalled  by  each  pupil,  out  of  a  possible 
fifteen;  of  the  order  of  recall,  that  is,  the  sequence  in  which 
the  objects  were  named;  and  of  the  order  preserved  in  placing 
the  objects  on  the  circle.  An  object  is  said  to  be  in  a  'correct* 
position  when  it  is  located  upon  the  circle  in  a  position  exactly 
corresponding  to  its  original  position  on  the  disc.  Two  objects 
were  said  to  be  in  a  'relatively'  correct  position  when  they 
simply  changed  places  in  location, — were  transposed.  Or,  if 
two  objects  in  adjacent  positions  on  the  disc  were  given  a 
corresponding  location  upon  the  circle,  but  not  arranged 
properly  as  regards  other  objects  in  the  group,  the  placing 
was  said  to  be  relatively  correct.  As  only  objects  not  in- 
cluded in  the  list  of  those  correctly  placed  are  included  in  the 
'  relatively  correct '  column,  the  average  for  the  former  is  usu- 
ally greatly  in  excess  of  the  latter.  Whenever  the  average  for 
correct  placing  is  relatively  high,  the  average  for  relative 
placing  is  considerably  lessened.  There  are  twenty  judgments 
when  the  objects  are  displayed  singly  and  twenty  when  they 
are  displayed  three  together. 


74 


ARTHUR  H.  CHAMBERLAIN 


THE  RESULTS 

Table  I  shows  the  results  of  the  test  in  the  three  grades 
with  the  two  methods  of  exposure. 

These  results  are  then  analyzed  in  several  tables  that 
bring  out:  (i)  The  effect  of  the  different  methods  of  display 
without  regard  to  grade,  sex  or  arrangement  of  objects;  (2) 
The  effect  of  the  particular  grade  of  pupil  upon  total  recall, 
correct  and  relative  placing  and  the  like;  (3)  The  effect  of 
sex  upon  total  recall,  the  recall  of  boys'  and  girls'  groups,1  etc. 

TABLE  I 


Sex 

Av.  No. 
Recalled 

Av.  No. 

Correctly 
Placed 

Av.  No. 
Relatively 
Placed 

Av.  No. 
Recalled, 
Boys' 
Group 

Av.  No. 

Recalled, 
Girls' 
Group 

M.V. 
of  Total 
Recalled 

Grades: 

One  at  a  time   .... 

Boys 

74 

5-7 

.7 

2.9 

2.7 

•17 

Girls 

8.1 

54 

•9 

2.6 

3 

•5 

Both 

7-75 

5-55 

.8 

2-75 

2.8S 

.61 

Three  at  a  time.  ..  . 

Boys 

9.1 

6.4 

•9 

2.9 

3-7 

.92 

Girls 

8 

5-5 

•7 

34 

3 

4 

Both 

8.55 

5-95 

.8 

3-iS 

3-35 

.66 

Grade  5  : 

One  at  a  time  

Boys 

10.5 

3 

2-5 

3-6 

3-3 

•7 

Girls 

9.2 

2-3 

34 

2.8 

3-3 

.04 

Both 

9.85 

2.65 

2-95 

3-2 

3-3 

•37 

Three  at  a  time.  .  .  . 

Boys 

9-5 

3-7 

2.9 

2.9 

3-2 

4 

Girls 

9-5 

2.4 

3-7 

3-3 

3 

.1 

Both 

9-5 

3-05 

3-3 

3-i 

3-i 

•25 

Grade  8: 

One  at  a  time 

Boys 

Q  2 

Si 

I  Q 

2  7 

•5   A 

.04. 

Girls 

96 

'  i 
7-i 

i.y 

4 

**/ 

3-8 

J'T 

3-2 

•WT 

.24 

Both 

94 

6.4 

I-I5 

3-25 

3-3 

.14 

Three  at  a  time.  .  .  . 

Boys 

10 

6.4 

2-3 

3-i 

34 

4 

Girls 

IO.I 

6.6 

2.1 

3-i 

3-7 

•5 

Both 

10.05 

6-5 

2.2 

3-i 

3-55 

.46 

Table  II.  shows  the  collective  results  with  the  two  methods 
of  display. 

TABLE  II 


Method  of  Display 

Av.  No. 
Recalled 

Av.  No. 
Correctly 
Placed 

Av.  No. 
Relatively 
Placed 

Av.  No. 
Recalled, 
Boys'  Group 

Av.  No. 
Recalled, 
Girls'  Group 

M.V. 
of  Total 
Recall 

Singly  

9 

9-37 

4.87 
5.166 

1.633 
2.1 

3-07 
3.12 

3-IS 

3-33 

**i 

1.46 

Three  at  a  time  .... 

1  The  letters  G.  and  B.  will  be  used  throughout  as  referring  to  the  objects  spoken 
of  as  the  girls'  and  boys'  group  respectively. 


MEMORY  TEST 


75 


The  display  of  the  objects  three  at  a  time  gives  an  ad- 
vantage in  the  average  number  of  objects  recalled,  as  well  as 
in  the  average  number  correctly  placed.  When  shown  three 
together  the  relative  placing  also  is  better  than  when  the 
objects  are  displayed  singly.  The  tendency  to  recall  the  G. 
or  B.  group  receives  very  slight  advantage  in  any  one  method 
of  display  over  another.  The  M.V.  of  total  recall  varies  only 
slightly  in  the  two  methods. 

Table  III.  shows  comparative  results  in  grades  three,  five 
and  eight. 

TABLE  III 


Grade 

Av.  No. 
Recalled 

Av.  No. 
Correctly 
Placed 

Av.  No. 
Relatively 
Placed 

Av.  No. 
Recalled, 
Boys'  Group 

AT.  No. 

Recalled, 
Girls'  Group 

M.V. 
of  Total 
Recall 

3 

8.15 

9.67 
9.72 

575 
2.8S 
6-45 

.8 
3-12 
1.67 

2-95 
3-15 

3-17 

3-i 

3-2 
34 

1.63 

I-3I 

1.30 

The  pupils  of  the  fifth  grade  show  a  marked  superiority 
over  those  of  the  third  grade  in  the  average  number  recalled. 
The  eighth  grade  is  not  greatly  in  advance  of  the  fifth  in  this 
particular.  In  correct  placing,  the  third  grade  is  almost 
abreast  of  the  eighth,  while  the  fifth  grade  drops  back  to 
one  half  the  showing  made  by  the  third.  In  relative  placing, 
the  fifth  grade  students  far  excel  those  of  the  third  and  are 
much  superior  to  the  eighth.  The  fifth  and  eighth  grades 
show  about  equal  power  in  recall  of  the  B  group,  while  the 
third  grade  makes  nearly  as  good  a  showing.  In  every  grade 
the  average  for  recall  of  the  G  group  is  slightly  better  than  that 
of  the  B  group. 

Table  IV.  shows  the  effect  of  sex  in  all  grades. 

TABLE  IV 


Sex 

Av.  No. 
Recalled 

Av.  No. 
Correctly 
Placed 

Av.  No. 

Relatively 
Placed 

Av.  No. 
Recalled, 
Boys'  Group 

Av.  No. 
Recalled, 
Girls'  Group 

M.V.  of 
Total  Recall 

Boys  . 
Girls  . 

9.28 
9.08 

5-15 

4.88 

1.86 

1.86 

3-02 
3.16 

3-28 

3-2 

1-43 
1.30 

Table  V  shows  the  relation  of  boys  to  girls  in  the  different 
grades. 


76 


ARTHUR  H.  CHAMBERLAIN 
TABLE  V 


Grade 

Sex 

Av.  No. 

Recalled 

Av.  No. 

Correctly 
Placed 

Av.  No. 
Relatively 
Placed 

Av.  No. 

Recalled, 
Boys'  Groupjj 

Av.  No. 
Recalled, 
Girls'  Group 

M.V.  of 

Total  Recall 

3 

5 
8 

Boys 
Girls 
Boys 
Girls 
Boys 
Girls 

8.25 
8.05 

10 

9-35 
9.6 

9-85 

6.O5 
545 

3-35 
2-35 
6.05 
6.85 

.8 
.8 
2.7 
3-55 

2.1 

1.25 

2.9 

3 

3-25 
3-05 
2.9 

345 

3-2 
3 
3-25 
3-iS 
34 
345 

1-55 
145 

i-SS 
1.07 

1.22 
I.38 

In  the  third  and  fifth  grades,  the  boys  have  a  slight  ad- 
vantage over  the  girls  in  the  total  number  recalled  and  in  the 
number  correctly  placed.  The  objects  composing  the  G 
group  are  recalled  somewhat  better  by  each  sex.  The  ratio 
between  the  recall  by  girls  and  boys  of  the  B  group  and  the 
G  group  is  only  slightly  different  from  the  ratio  between  girls 
and  boys  in  the  total  recall. 

CONCLUSIONS  FROM  THE  STUDY 

The  results  of  the  various  experiments  would  seem  to 
justify  the  following  conclusions: 

1.  Recall  is  stronger  when  the  objects  are  seen  three  at  a 
time  than  when  shown  singly. 

2.  The    average    for    total    recall    shows    a    considerable 
increase  from  the  third  to  the  fifth,  with  an  almost  negligible 
increase  from  the  fifth  to  the  eighth  grades.     This  difference 
is  emphasized  when  we  consider  that  the  age-difference  be- 
tween the  fifth  and  eighth  grade  was  approximately  twice  as 
great  as  that  between  the  third  and  fifth.     In  other  words, 
ability  to  memorize  or  to  recall  does  not  increase  regularly  with 
advance  in  age  or  experience. 

3.  The  total  average  of  recall  for  all  grades  and  with  all 
methods  of  exposure  of  objects  shows  the  girls  not  to  be  super- 
ior to  the  boys.     This  is  not  in  accord  with  the  usual  outcome 
of  experiments  in  memory.     No  clear  difference  is  discernible 
between  the  boys  and  the  girls  in  the  attraction  exerted  by 
the  so-called  boys'  group  and  girls'  group  of  objects;  for  both 
sexes  the  girls'  group  was  slightly  more  attractive. 


XXL     PRACTICE   IN  ASSOCIATING  NUMBER- 
NAMES  WITH  NUMBER-SYMBOLS1 

BY  WARNER  BROWN 

In  a  recent  study2  the  writer  employed  the  difference 
between  the  time  required  to  perceive  and  name  a  series  of 
colors  and  the  time  required  to  read  the  same  color-names 
when  they  are  printed  out  in  type  as  a  typical  instance  of  the 
general  rule  that  it  takes  longer  to  perceive  and  name  a  simple 
object  than  to  perceive  and  name  a  word.  At  that  time 
reference  was  made  to  an  experiment  by  Bourdon  in  which  the 
time  for  calling  out  the  number  of  points  of  light  in  a  small 
group  was  said  to  be  no  greater  than  the  time  for  naming  the 
corresponding  arabic  numeral.3  On  the  basis  of  this  experi- 
ment Bourdon  argues  that  the  process  of  perceiving  a  small 
number  of  points  as  a  number  is  no  more  complicated  than 
the  process  of  perceiving  the  symbol  of  the  number.  If  this 
is  correct  it  means  that  it  is  possible  in  this  case  to  associate 
the  name  of  an  object  with  the  object  itself  as  quickly  as 
with  the  symbol  of  the  name  and  this  would  make  it  seem 
probable  that  the  association  processes  in  color-naming  involve 
difficulties  peculiar  to  themselves  and  are  not  typical  of  the 
general  situation  in  which  simple  objects  are  perceived  and 
named. 

What  follows  is  an  attempt  to  discover  whether  number- 
naming  is  really  a  process  which  is  free  from  the  time-con- 
suming difficulties  of  color-naming.  A  practice  experiment 
was  devised  in  which  number-naming  was  subjected  to  the 
same  analysis  that  was  applied  in  the  previous  case  to  color- 
naming.  The  material  for  the  experiment  was  all  prepared 
with  the  typewriter.  It  consisted  of  four  sheets,  each  con- 

1  Studies  from  the  Psychological  Laboratory  of  the  University  of  California. 

2  This  REVIEW,  p.  45. 

3  Rev.  philos.,  Vol.  65,  1908,  p.  426. 

77 


78  WARNER  BROWN 

taining  ten  lines  of  ten  items.  The  first  sheet  contained  the 
type-written  words  one,  two,  three,  and  four.  There  were  25 
words  of  each  sort,  arranged  in  irregular  order  with  not  more 
than  3  nor  less  than  2  of  a  kind  to  a  line.  Four  different  sets 
of  sequences  of  words  were  used  to  prevent  memorization  of 
any  particular  sequence.  The  lines  were  separated  by  triple 
space  and  the  words  were  separated  from  each  other  by  the 
space  of  three  letters.  The  second  sheet  contained  the  arabic 
numerals  corresponding  to  the  words  of  the  first  sheet  so 
arranged  that  each  symbol  occupied  a  position,  which  was 
relatively  the  same  as  the  center  of  the  corresponding  word 
in  the  sheet  of  words.  In  this  way  the  eye-movement  factor 
was  kept  as  nearly  constant  as  possible.  The  third  sheet 
(known  as  'dots')  was  made  up  of  dots  arranged  to  represent 
the  numbers  as  follows:  one  was  represented  by  a  period', 
two  by  a  colon',  three  by  a  colon  with  a  period  after  it;  four 
by  two  colons.  The  fourth  sheet  represented  the  numbers  by 
an  appropriate  number  of  oblique  strokes  ('scores')  made 
with  the  key  used  in  printing  fractions  on  the  typewriter. 

The  time  was  measured  which  was  required  to  read  aloud 
the  one  hundred  items  on  each  of  these  sheets.  The  sheets 
were  read  one  after  the  other  in  the  order  given  above,  and 
then  all  four  were  read  again,  so  that  the  time  stated  for 
each  sheet  on  each  day  of  practice  is  the  average  of  two 
records,  the  first  and  fifth,  second  and  sixth,  etc.1 

The  accompanying  table  gives  the  results  of  eleven  days' 
practice  with  this  material  on  the  part  of  twenty-four  stu- 
dents. None  of  these  students  knew  the  real  purpose  of  the 
experiment.  They  were  all  encouraged  in  the  supposition, 
which  came  naturally  to  all  of  them,  that  they  would  be  able 
with  practice  to  read  the  "dots"  or  "scores"  as  fast  as  the 
words  or  symbols. 

1  The  experiment  with  colors  referred  to  above,  made  it  clear  that  there  is  no 
considerable  difference  in  time  between  successive  trials  on  the  same  day.  The 
average  time  for  naming  100  colors  was  found  to  be  42.3,  42.3,  43.0,  and  42.8  seconds 
for  4  successive  trials;  the  time  for  4  successive  trials  of  reading  100  words  was  29.0, 
30.4,  29.9,  and  30.5  seconds.  There  can  be  no  serious  objection,  therefore,  to  com- 
paring the  rate  of  reading  one  sheet  with  the  rate  of  reading  another  sheet  when  their 
sequence  is  the  same  each  time.  It  is  understood,  of  course,  that  the  order  of  the 
items  on  the  sheet  is  different  on  successive  sheets. 


NAMES  AND  NUMBER-SYMBOLS 


79 


TABLE  FOR  ELEVEN  DAYS  OF  PRACTICE  ON  THE  PART  OF  24  PERSONS,  SHOWING 
THE  AVERAGE  TIME  REQUIRED  TO  NAME  IOO  ITEMS  PRESENTED  AS  WORDS,  AS  ARABIC 
NUMERALS,  AS  GROUPS  OF  DOTS,  OR  AS  GROUPS  OF  SCORES;  AND  SHOWING  FURTHER 
THE  RATIO  OBTAINED  BY  DIVIDING  THE  TIME  FOR  THE  ARABIC  NUMERALS  INTO  THE 
TIME  FOR  EACH  OF  THE  OTHER  PERFORMANCES. 


Ratio  of  Arabic  to  : 

Day 

Word 

Arabic 

Dot 

Score 

Word 

Dot 

Score 

I 

30.1 

27.8 

39-6 

36.0 

1.  08 

.42 

1.29 

2 

28.9 

26.5 

35-9 

34-2 

1.09 

•35 

1.29 

3 

27-6 

25.8 

344 

33.2 

1.07 

•33 

.29 

4 

27.1 

25.0 

34-7 

32.5 

1.  08 

•39 

•30 

26.6 

2S.O 

34-o 

324 

.06 

•36 

.29 

6 

26.S 

24.7 

33-0 

31-7 

.07 

•34 

.28 

7 

26.3 

24-3 

32-3 

30.5 

.08 

•33 

•25 

8 

25-7 

24.2 

31.8 

30-9 

.06 

•32 

•27 

9 

25-5 

23.8 

3i-9 

31.0 

.07 

•34 

•30 

10 

25.1 

23.6 

31-2 

304 

.07 

•32 

.29 

ii 

25.0 

234 

30.9 

29.9 

.07 

•32 

.28 

The  result  shows  that  the  time  required  to  perceive  and 
name  the  number  of  a  small  group  of  marks  is  longer  than  the 
time  required  to  perceive  and  name  the  corresponding  word 
or  the  arabic  symbol  of  the  number.  In  this  respect  the 
results  agree  perfectly  with  the  experiment  in  naming  colors, 
and  support  the  general  dictum  that  the  naming  of  objects  is 
slower  than  the  naming  of  words.1 

The  same  peculiar  inhibitions  appear  in  the  reading  of 
the  "dots"  or  " scores"  which  are  encountered  in  color- 
naming.  Some  persons  are  more  troubled  by  the  "dots" 
and  others  find  more  difficulty  in  the  case  of  the  "scores" 
but  no  one  notes  any  considerable  disturbance  of  this  kind  in 
the  case  of  the  words  or  arabic  symbols. 

This  experiment  agrees  with  color-naming  in  the  essential 
point  that  the  ratio  between  the  time  required  to  name  an 
object  and  the  time  required  to  name  its  symbol  resists  the 

1  As  a  matter  of  fact  Bourdon's  statement  that  the  dots  are  named  as  fast  as  the 
symbols  does  not  seem  to  be  fully  supported  even  by  his  own  figures.  His  interpreta- 
tion of  his  data  raised  a  doubt  which  the  results  of  the  present  experiment  tend  to 
clear  away.  There  is  no  striking  conflict  between  the  original  data  of  the  two  experi- 
ments. The  method  of  serial  reactions  which  has  been  used  in  the  present  case  un- 
doubtedly tends  to  magnify  the  loss  of  time  in  the  association  process  and  might 
reasonably  be  expected  to  show  a  greater  difference  in  time  between  the  two  processes 
than  would  be  shown  by  Bourdon's  method  of  single  reactions.  But  it  is  not  probable 
that  the  serial  reactions  would  show  a  difference  unless  the  single  reactions  also  gave 
some  difference  and  as  a  matter  of  fact  Bourdon's  reactions  do  give  some  difference. 


So  WARNER  BROWN 

action  of  practice.  This  seems  to  argue  in  both  cases  that 
previous  practice  is  not  the  basis  of  the  relative  rapidity  of 
the  latter  process.  So,  too,  the  fact  that  the  process  of  naming 
the  symbol  is  itself  capable  of  a  very  material  improvement 
through  practice  precludes  our  speaking  of  it  as  automatic  in 
comparison  with  another  process  (the  slower  one  of  naming 
the  object)  which  improves  no  faster.  It  does  not  appear 
probable  that  differences  in  previous  practice  have  much  to  do 
with  the  relative  speed  of  the  two  processes. 

The  present  experiment  confirms  the  inference  drawn  from 
one  part  of  the  color  experiment  that  phonetic  symbols  such 
as  letters  do  not  seem  to  be  responsible  for  the  advantage  in 
speed  of  one  association  process  over  the  other.  It  might  be 
thought  that  the  sight  of  the  different  letters  would  guide  the 
complex  movements  of  the  vocal  organs  in  uttering  the  word, 
and  so  facilitate  the  reaction  to  a  word,  but  it  appears  that 
the  words  with  their  phonetic  symbols  can  not  be  read  quite 
as  fast  as  the  arbitrary  arabic  symbols  which  contain  no 
phonetic  elements.  This  is  true  for  nearly  every  individual 
person  and  in  spite  of  the  fact  that  the  spacing  of  the  words 
and  figures  on  the  page  gave  nearly  normal  conditions  of  eye- 
movement  for  the  words  and  rather  unusual  conditions  for  the 
arabic  symbols. 

In  conclusion  it  may  be  said  that  the  causes  of  the  delay 
of  the  association  processes  in  naming  a  simple  object  remain 
as  obscure  as  ever.  But  on  the  negative  side  it  seems  clear 
that  the  greater  speed  with  which  words  are  named  does  not 
depend  upon  an  advantage  in  practice  and  does  not  depend 
upon  the  suggestiveness  of  the  letters  in  the  words. 


XXII.     INCIDENTAL   MEMORY    IN   A   GROUP    OF 

PERSONS1 

BY  WARNER  BROWN 

The  study  which  is  reported  below  leads  to  the  conclusion 
that  the  factors  which  make  it  easy  or  difficult  for  an  individ- 
ual to  recall  certain  of  the  incidental  observations  of  his  past 
experience  also  tend  to  affect  in  the  same  way  the  collective 
memories  of  a  large  group  of  persons. 

The  material  for  the  investigation  was  obtained  by  having 
the  members  of  a  large  college  class  write  down,  in  a  limited 
time,  the  names  of  all  of  the  advertisements  which  they  could 
remember  having  seen  recently  in  the  street-cars.  They  also, 
after  making  out  the  list,  wrote  down  answers  to  certain 
questions  about  the  advertisements,  but  that  has  nothing  to 
do  with  the  present  report.  The  experiment  was  performed 
twice.  The  first  time  175  persons  wrote  lists.  The  lists 
contained  in  all  896  items  and  these  items  were  found  to 
include  mentions  of  215  different  advertisements.  Thus  the 
average  person  recalled  5.1  advertisements,  and  the  average 
advertisement  was  mentioned  4.2  times.  Table  I  is  arranged 

TABLE  I 


The  Number  of 
Items  in  the  List 

The  Number  of  Per- 
sons Giving  a  List  of 
this  Length 

The  Total  Number  of 
Items  in  the  Lists  of  this 
Length 

The  Relative  Frequency 
of  Occurrence  of 
Such  Items 

0 

21 





I 

8 

8 

23.1 

2 

17 

34 

24.8 

3 

.          15 

45 

16.2 

4 

22 

88 

22.6 

16 

80 

20.8 

6 

20 

120 

18.0 

7 

13 

91 

21.9 

8 

12 

96 

19.7 

9 

9 

81 

IS-7 

10 

7 

70 

14.4 

ii 

6 

66 

14.4 

12 

3 

36 

11.4 

13 

3 

39 

9-5 

H 

3 

42 

12.5 

From  the  Psychological  Laboratory  of  the  University  of  California. 


8l 


82 


WARNER  BROWN 


according  to  the  length  of  the  lists  and  shows  the  number  of 
persons  who  gave  a  list  of  each  length  from  o  to  14  items. 
Table  II.  shows,  roughly,  the  number  of  mentions  accorded  to 

TABLE  II 


The  Number 
of  Items  Men- 
tioned 

The  Number  of 
Mentions  Received 
by  Each  of  These 
Items 

The  Average 
Position  of  These 
Items  in  the  Lists 

The  Number  of 
Times  One  of  These 
Items  is  Found 
at  the  Head  of  a 
a  List,  Per  Cent. 

The  Number  of 
Times  One  of  These 
Items  is  Found  in 
the  8th  or  a  Lower 
Position,  Per  Cent. 

;s3 
152 

(1 

54 
5-3 

5-7 
n-5 

22.6 
19.2 

34 

2 

5-0 

n.8 

I9.I 

8 

3 

4.6 

ii.  i 

I4.8 

H 

4  or  5 

3-9 

14.8 

14.7 

8 

6  or  7 

5-2 

7.8 

19.6 

8 

7  or  8 

4-5 

11.9 

17.0 

7 

8  or  9 

5-o 

10.2 

18.6 

6 

9,  10,  ii 

44 

17-5 

10.5 

4 

12-15 

3.6 

16.6 

7-4 

3 

15-18 

3.8 

28.0 

IO.O 

3 

18-20 

4.0 

28.1 

12.3 

2 

23,30 

.8 

24-5 

iS-i 

I 

55 

3-5 

2O.O 

5-5 

I 

55 

2.9 

30-9 

5-5 

I 

58 

3-o 

24.1 

5-2 

different  advertisements.  Thus  105,  or  nearly  half  of  them, 
are  mentioned  by  but  one  person,  while  three  of  them  are 
mentioned  more  than  50  times  each.  These  three  'best' 
advertisements  (Arrow  collars,  Spearmint  gum,  and  a  local 
confectioner),  receive  almost  one  fifth  of  all  the  mentions. 

In  what  has  just  been  said  we  have  before  us  the  essential 
points  upon  which  the  investigation  is  to  be  based.  Some  of 
the  advertisements  are  much  better  remembered  than  others; 
and  at  the  same  time  some  persons  remember  a  larger  number 
of  advertisements  than  other  persons  do.  Is  it  true  then, 
that  the  advertisements  which  are  remembered  by  the  greatest 
number  of  persons  are  the  ones  which  permit  of  the  easiest 
recall  on  the  part  of  those  persons  who  can  remember  several? 
The  answer  is  obtained  by  finding  whether  the  advertisements 
which  are  forgotten  by  most  persons  are  written  down  later 
than  those  which  can  be  recalled  by  more  people.  The  result 
shows  (Table  II.),  that  in  the  average,  one  of  the  105  which 
are  mentioned  only  once  is  not  mentioned  until  five  others 
have  been  mentioned.  The  most  popular  advertisement  has 


INCIDENTAL  MEMORY  83 

an  average  position  of  third.  In  other  words  the  average 
person  will  write  down  an  item  which  many  other  persons  can 
remember,  sooner  than  he  will  write  down  one  which  only  a 
few  can  remember.  Less  than  9  per  cent,  of  the  105  straggling 
items  are  found  at  the  head  of  a  list,  while  about  24  per  cent, 
of  all  the  mentions  of  the  most  popular  one  are  found  at  the 
top  of  a  list. 

Table  II.  has  been  arranged  to  show  the  result  when  the 
whole  number  of  mentions  is  broken  up  into  16  approximately 
equal  groups  of  from  50  to  60  cases  each,  on  the  basis  of 
the  frequency  with  which  the  items  were  mentioned.  The 
table  shows  the  average  position  of  the  item  in  the  list; 
the  items  most  frequently  mentioned  stand  ahead  of  the  rarer 
items  in  the  lists.  It  also  shows  for  each  advertisement  or 
group  of  advertisements  the  proportion  of  its  mentions  which 
stand  at  the  head  of  a  list;  those  most  frequently  mentioned 
are  more  apt  to  be  mentioned  at  the  very  start.  The  corre- 
lation of  rank 

6SZ)2 


in  order  of  mention,  in  the  above  table,  with  average  position 
in  the  list  is  .85,  and  with  proportion  of  leading  mentions  it  is 

.76. 

While  conducting  this  investigation  the  writer  labored 
under  the  impression  that  those  persons  who  mentioned  only 
a  few  items  would  be  apt  to  have  peculiar  reasons  for  re- 
membering the  few  advertisements  which  they  could  recall, 
and  that  they  would  mention  many  wild  and  eccentric  ex- 
amples. The  analysis  of  the  data  shows  that  such  can  not 
be  the  case.  The  sporadic  item  very  seldom  occurs  early  in 
any  list;  it  can  only  rarely  occur  in  a  short  list.  The  last 
column  of  Table  I.  shows  the  relative  frequency  with  which  the 
items  in  lists  of  different  lengths  are  mentioned.  This  is 
found  by  listing  all  of  the  items  in  all  of  the  lists  of  a  certain 
length  and  entering  opposite  that  item  the  total  number  of 
times  that  it  is  mentioned  in  all  of  the  lists,  i.  e.,  the  frequency 
of  the  item.  The  total  amount  of  all  of  these  frequencies  is 
then  divided  by  the  total  number  of  items  concerned.  The 


84  WARNER  BROWN 

results  of  this  computation  make  it  evident  that  the  items 
which  occur  in  a  very  short  list  are  items  which  are  more  often 
remembered  than  the  items  which  occur  in  longer  lists.  As 
the  length  of  the  list  increases  it  includes  more  and  more 
sporadic  or  infrequent  items.  The  original  data  show  that  of 
the  42  items  contained  in  the  one-item  or  two-item  lists  three- 
quarters  were  mentioned  by  more  than  ten  different  people, 
while  of  the  42  items  contained  in  the  fourteen-item  lists 
three  quarters  were  advertisements  receiving  less  than  ten 
mentions  and  one  quarter  were  rarities,  mentioned  by  less 
than  four  persons.  Turning  to  Table  II.,  the  last  column,  it 
is  evident  that  the  less  frequently  mentioned  items  are  more 
apt  than  the  others  to  find  mention  toward  the  end  of  a  long 
list,  in  the  eighth  or  a  still  lower  position.  The  correlation 
between  rarity  of  occurrence  and  low  position  in  the  list  is  .78. 

The  facts  warrant  the  conclusion  that  the  items  in  the 
short  lists  are  not  determined  by  individual  or  special  con- 
ditions, but  are  simply  the  items  which  are  most  easily  re- 
membered. There  seems  to  be  good  reason  to  believe  that 
the  same  factors,  whatever  they  are,  which  cause  an  adver- 
tisement, or  other  similar  incidental  impression,  to  be  recalled 
early  in  the  memory  of  one  individual  cause  it  to  be  recalled 
early  in  the  memory  of  another,  regardless  of  the  number  of 
items  which  may,  or  may  not,  follow  after  it.  The  difference 
between  individuals  in  this  respect  seems  to  be  a  difference  in 
the  number  of  the  items  recalled,  and  not  in  the  kind  or  iden- 
tity of  the  items.  Items,  which,  for  any  reason,  are  difficult 
to  recall  appear  late  in  long  lists  and  do  not  appear  at  all  in 
short  lists. 

This  conclusion  is  significant  for  experimental  work  in 
memory  as  it  puts  a  new  value  upon  the  relative  position 
of  the  items  in  the  recalled  series.  Apparently  the  first 
items  to  be  recalled  are  generally  those  which  make  a  uni- 
versal appeal;  the  special  personal  appeals  are  reported  later, 
or  not  at  all.  Moreover  there  seems  reason  to  believe  that 
"poor"  incidental  memory  involves,  at  least  with  this  ma- 
terial, no  other  abnormality  than  poverty  or  "  weakness." 

So  far  as  the  actual  advertisements  which  were  used  in 


INCIDENTAL  MEMORY  5 

the  investigatipn  are  concerned,  it  is  important  to  note  that 
some  make  a  much  more  lasting  impression  than  others. 
The  difference  can  not  be  expressed  by  saying  that  one  ad- 
vertisement appeals  to  more  persons  than  another;  it  must 
be  stated  as  a  difference  in  the  strength  of  the  appeal. 
The  good  advertisement  makes  an  appeal  so  strong  that  it 
can  not  be  forgotten;  the  poor  advertisement  is  forgotten  by 
all  except  those  persons  who  can  remember  very  weak  im- 
pressions. 

The  results  of  this  investigation  are  fully  confirmed  by  a 
repetition  of  the  experiment  some  five  months  later  with 
another  college  class,  among  the  members  of  which  there  were 
only  a  few  who  had  taken  part  in  the  first  experiment.  As  a 
result,  perhaps,  of  the  interest  aroused  by  the  first  experiment, 
the  average  number  of  items  per  student  rose  from  5.1  to  9.9. 
The  number  failing  to  report  any  advertisements  fell  from  21 
to  3  although  the  class  was  only  a  third  smaller.  There  were 
no  lists  of  one  or  two  items  presented.  In  spite  of  the  larger 
number  of  items  per  student,  the  variety  of  the  items  increased 
to  such  an  extent  that  the  average  number  of  mentions  per 
advertisement  only  increased  from  4.2  to  4.6.  Under  these 
changed  conditions  all  of  the  conclusions  of  the  first  experi- 
ment were  confirmed.  The  correlation  between  frequency 
of  mention  and  high  position  in  the  list  was  found  to  be  .76. 
Of  the  straggling  single  items  only  7  per  cent,  were  found  at 
the  head  of  a  list,  while  24  per  cent,  of  the  mentions  of  the 
most  popular  advertisement  headed  lists.  The  correlation 
between  popularity  and  primacy  was  found  to  be  .61.  On 
the  other  hand  the  correlation  between  infrequency  and  a 
position  somewhere  lower  than  ninth  on  the  list  was  found  to 
be  .76. 

In  conclusion  it  may  be  said  that  the  items  which  appeal 
to  the  largest  number  of  persons  make  the  strongest  appeal 
to  most  of  those  persons,  and  that  those  items  which  appeal 
to  only  a  few  make  a  weak  appeal  even  to  them. 


VOL.  XXII.  No.  2  March,  1915 


THE  PSYCHOLOGICAL  REVIEW 


A    PROPOSED    CLASSIFICATION    OF    MENTAL 
FUNCTIONS 

BY  GEORGE  A.  COE 

Union  Theological  Seminary 

Whenever  anything  is  declared  to  be  a  function  of  mind 
we  should  be  able  to  discover  both  the  general  sense  in  which 
the  term  *  function'  is  used,  and  also  the  setting  of  the  par- 
ticular function  in  question  within  a  functional  whole.  This 
is  as  much  as  to  say  that  classification  of  mental  functions 
should  have  a  place  in  functional  psychology  that  will  cor- 
respond to  the  position  now  occupied  in  structural  psychology 
by  lists  of  mental  elements  and  modes  of  combination.  Up 
to  the  present  time  such  a  systematic  background  has  been 
lacking.  As  a  consequence  the  undefined  fringe  of  meaning 
in  discussions  of  functions  leaves  still  too  much  room  for 
misunderstanding  one  another,  or  even  oneself.  Further, 
the  lack  of  classification  implies  that  we  are  not  yet  ready 
to  begin  describing  functions  in  terms  of  functional  laws. 
Such  is  the  unsatisfactory  situation  out  of  which  the  present 
article  attempts  to  take  a  single  step.  The  results  are  neces- 
sarily preliminary  and  tentative;  the  most  that  I  can  hope  for 
is  that  other  investigators  will  be  sufficiently  interested  to 
make  good  my  deficiencies. 

The  approaches  thus  far  made  toward  a  classification  of 
mental  functions  fall  into  the  following  classes: 

(a)  Affirmations  of  the  purposive  character  of  mind,  with- 
out any  list  of  specific  functions.1 

1  E.  g.,  J.  E.  Creighton,  'The  Standpoint  and  Method  of  Psychology,'  Phil.  Rev., 
March,  1914;  H.  Munsterberg,  'Psychology,  General  and  Applied,'  1914,  and  R.  M. 
Ogden,  'Introduction  to  General  Psychology,'  1914. 

87 


88  GEORGE  A.  COE 

(b)  The  oft-made  assertion  that  the  fundamental  functions 
of  all  life,  mind  included,  are  nutrition  and  reproduction. 
At  a  later  point  I  shall  ask  what,  as  a  matter  of  fact,  mind 
does  with  these  two  vital  processes.     At  once,  however,  I 
would  point  out  that  some  of  the  so-called  'irradiations'  from 
primitive  hunger  and  love — for  example,  science — have  char- 
acters of  their  own  which  it  requires  some  violence  to  call 
either  nutritive  or  reproductive. 

(c)  To  each  item  in  a  structural  classification  of  mind 
Angell  has  added  the  question,  What  is  its  function?  There 
results  what  might  be  called  an  engineer's  drawing  of  mind  as 
an  adjusting  mechanism.     It  goes  far  toward  supplying  the 
functional  classification  that  I  am  seeking,  and  as  a  conse- 
quence I  shall  borrow  rather  freely  from  it.     That  it  needs 
supplementing,    however,   should   be   clear   from   these   two 
considerations:  First,  Angell's  list  of  functions  is  not  based 
upon  similarities  and  differences  among  the  functions  them- 
selves; he  merely  finds   and   describes   a  function  for  each 
element  of  structure.     Second,  his  genetic  method  keeps  his 
eyes  fixed  upon  the  earliest  mental  reaction,  the  terminus  a 
quo,  whereas  our  problem — the  direction  of  mental  movement 
— requires  us  to  consider  also  the  most  developed  reaction  as 
a  terminus  ad  quern.     I  find  no  fault  with  Angell  for  not 
answering  questions  that  he  does  not  raise,  but  functional 
psychology  must  surely   incorporate  into   itself   a  fuller  de- 
scription of  the  interests  of  developed  mind.     After  we  have 
named  early  utilities,  and  even  after  we  have  made  such 
generalizations  as  that  mind  extends  the  control  and  organ- 
ization of  movements,  something  in  the  nature  of  function 
still  remains  over.     To  illustrate:  If  you  should  ask  what  are 
the  functions  of  a  dividing  engine,  I  might  answer  by  showing 
how  each  wheel  and  lever  contributes  to  the  accurate  control 
of  movement,  and  I  might  generalize   by  saying  that  this 
instrument  as  a  whole  has  the  function  of  so  adjusting  our 
motions  as  to  enable  us  to  make  extremely  minute  divisions 
of  a  surface.     This  would  be  a  functional  description,  no 
doubt,  yet  beyond  it  lies  the  destination  of  the  whole,  namely, 
certain  sciences  in  the  interest  of  which  the  dividing  engine 


MENTAL  FUNCTIONS  89 

exists  at  all.  Just  so,  the  proposition  that  mind  increases 
the  extent  and  the  fineness  of  our  adjustments  needs  to  be 
supplemented  by  inquiry  into  the  terminal  meaning  of  the 
whole. 

(d)  A  fourth  approach  to  a  functional  classification  pro- 
ceeds as  follows:  Mental  functions  are  correlative  with  inter- 
ests; interests  have  their  roots  in  instinctive  satisfactions; 
therefore  an  inventory  of  instincts  would  be  ipso  facto  a  list  of 
the  functions  of  mind.  Let  us,  then,  look  to  our  original 
nature,  that  is  to  our  unlearned  tendencies  to  react  in  specific 
ways,  to  give  attention  to  specific  sorts  of  object,  to  take  satis- 
faction in  predetermined  kinds  of  mental  occupation.  The 
program  is  attractive,  and  we  shall  see  that  it  yields  results 
that  have  an  important  bearing  upon  our  problem,  though 
not  quite  the  results  that  are  commonly  expected.  For,  first, 
the  *  original'  nature  of  man  means  the  part  of  his  nature  that 
is  disclosed  antecedently  to  all  culture,  that  is,  before  the 
mind  has  performed  some  of  its  most  characteristic  acts.1 
Second,  the  broad  mental  areas  traditionally  called  instincts 
are  disappearing  from  the  psychologic  map,  and  in  their 
stead  there  is  appearing  a  vast,  indefinite  number  of  narrow 
adjustment  acts.  For  example,  Thorndike  says  that  "reach- 
ing is  not  a  single  instinct,  but  includes  at  least  three  somewhat 
different  responses  to  three  very  different  situations."2  Thus, 
the  farther  back  we  go  in  our  mental  history  the  greater  the 
difficulty  of  functional  classification,  unless  we  constantly 
look  forward  as  well  as  backward.  On  the  other  hand,  the 
very  minuteness  and  rigor  of  Thorndike's  analysis  reveal 
certain  general,  forward-looking  tendencies.  Thus,  there  is 
a  tendency  to  be  or  to  become  conscious;3  there  is  an  original 
'love  of  sensory  life  for  its  own  sake';4  there  is  spontaneous 
preference  for  experiences  in  which  there  is  mental  control;5 
finally,  there  is  a  native  capacity  for  learning.6  In  short, 

1  E.  L.  Thorndike,  'The  Original  Nature  of  Man/  1913, ^198  f.;  also  'Education/ 
1912,  Ch.  v. 

2  'Original  Nature/  50. 

3  Ibid.,  170  f. 
«i4i. 

6 141  f. 
•171. 


90  GEORGE  A.  COE 

there  are  'original  tendencies  of  the  original  tendencies  .  .  . 
original  tendencies  not  to  this  or  that  particular  sensitivity, 
bond  or  power  of  response,  but  of  sensitivities,  connections 
and  responses,  in  general.'1  Here,  I  take  it,  is  where  interests, 
in  the  proper  sense  of  the  term,  come  in.  If  we  are  to  define 
our  mental  functions  by  our  interests,  we  must  consider  not 
merely  tendencies  to  this  or  that  sensitivity,  but  also  and 
particularly  our  tendencies  to  organize  or  do  something  with 
our  sensitivities.  Some  results  of  Thorndike's  analysis  of 
such  tendencies  I  shall  take  over  into  my  own  classification. 

(e)  Some  of  the  conditions  for  a  general  classification  of 
mental  functions  are  fulfilled  in  recent  discussions  of  value.2 
Here  function  is  treated  as  function;  it  is  not  confused  with 
elements  of  structure,  nor  is  a  given  function  identified  with 
its  earliest,  crudest  form.  Sense  of  direction  from  something 
to  something  is  here.  Urban's  list  of  values,  in  particular, 
conveys  a  sense  of  the  general  direction  of  the  movement  of 
mind.  What  is  still  needed  is  something  like  a  combination  of 
Angell,  Thorndike,  and  Urban.  The  reason  why  lists  of 
values  need  supplementing  is  twofold :  First,  they  do  not  com- 
prehend mind  as  a  whole,  for  example,  its  biological  aspects. 
Second,  several  types  of  value,  as  will  presently  appear,  are 
not  simple  functions,  but  functional  complexes. 

These  converging  lines  in  recent  psychology  may  be  sum- 
marily described  as  follows:  (i)  All  mental  process  what- 
soever is  purposive,  and  it  should  be  analyzed  from  this  as 
well  as  from  the  structural  standpoint — that  is,  mental  functions 
must  be  determined.  (2)  The  human  mind  is  functionally  as 
well  as  structurally  continuous  with  the  animal  mind,  so  that 
a  classification  of  functions  must  include  the  biological  point 
of  view.  (3)  The  termini  of  mind,  by  which  functions  are 
defined,  include  conscious  interests,  or  self-defining  ends. 
(4)  Several  specific  functions  of  both  the  biological  type  and 
the  conscious-interest  type,  have  been  defined  here  and  there 
in  scattered  places. 

What  remains  to  be  done  is  to  systematize  these  results; 

1 170. 

'The  chief  classifications  of  value  are  summarized  by  J.  S.  Moore  'The  System 
of  Values/  Jour.  Phil.,  VII  (1910),  282-291. 


MENTAL  FUNCTIONS  91 

to  discover,  and  if  possible,  fill  remaining  gaps;  and  to  show 
the  relation  of  the  resulting  functional  concepts  to  older, 
more  current  psychological  categories.  The  whole  must,  of 
course,  be  description,  not  evaluation.  The  work  of  func- 
tional psychology  is  not  to  tell  us  what  we  ought  to  prefer, 
but  to  determine,  as  a  matter  of  observable  fact,  what  mind 
does  actually  go  toward  and  'for.'  Two  main  divisions, 
each  with  several  subdivisions,  are  implied  in  what  has  already 
been  said. 

A.  Biological  Functions. — To  occupy  the  biological  stand- 
point— which  is  simply  a  point  of  view  used  temporarily  for 
certain  purposes,  and  not  necessarily  more  true  or  funda- 
mental than  other  points  of  view — is  to  think  of  living  beings 
without  reference  to  any  approvals  or  preferences,  any 
'better  and  worse.'  The  biological  functions  of  mind  consist 
in  quantitatively  determinable  increases  in  range  of  response 
to  environment.  Our  subdivisions  of  biological  functions, 
accordingly,  are  as  follows: 

1.  Increase  in  the  spatial  range  of  objects  responded  to. 

2.  Increase  in  the  temporal  range  of  objects  responded  to. 

3.  Increase  in  the  range  of  magnitudes  to  which  response  is 
made. 

4.  Increase  in  the  range  of  qualities  responded  to. 

5.  Increase  in  the  range  of  environmental  coordinations  to 
which  coordinated  responses  are  made. 

This  list  will  remain  the  same  whether  we  approach  the 
facts  from  the  behaviorist  standpoint  or  from  that  of  tra- 
ditional psychology.  I  call  these  functions  mental  for  two 
reasons:  Because  they  characterize  mind  in  its  most  conscious 
as  well  as  its  less  conscious  stages,  and  because  these  'direc- 
tions of  movement'  though  they  are  established  before  we 
reflect  upon  them,  become,  after  reflection,  conscious  pur- 
poses. 

The  relation  of  this  analysis  to  the  popular  categories, 
nutrition  and  reproduction,  requires  a  word  of  explanation. 
To  begin  with  nutrition,  what  has  mind,  as  a  matter  of  fact, 
to  do  with  it?  (a)  Mind  connotes  changes  in  the  feeding 
reaction  that  fall  under  one  or  more  of  the  above-listed 


92  GEORGE    A.  COE 

functions.  But  the  law  here  is  a  general  one;  it  applies 
likewise  to  protection  from  weather,  from  accidents,  and  from 
enemies,  and  it  applies  also  to  social  organization,  science, 
and  art.  As  far  as  range  of  response  is  concerned,  then,  we 
need  no  special  nutrition  category,  (b)  Mind  connotes 
success  in  a  competitive  struggle  over  a  limited  supply  of 
food.  Increase  of  mind  makes  a  difference  here,  but  in  what? 
Can  the  difference  be  expressed  in  terms  of  nutrition  ?  No;  for 
nutritive  functions  would  go  on  at  least  as  well  if  no  com- 
petition occurred,  or  if  the  mentally  inferior  animal  had 
happened  to  get  the  food  instead  of  the  mentally  superior 
one.  The  difference  made  by  mind  is  that  some  new  object 
or  quality  is  responded  to,  and  that  the  more  differentiated 
response  tends  to  be  perpetuated  by  inheritance.  Here  the 
function  appears  to  be  not  nutrition  but  the  production  of  a 
more  specialized  individual,  (c)  It  is  at  least  as  correct  to 
say  that  mind  moves  away  from  as  toward  nutrition.  For, 
correlative  with  the  growth  of  mind  goes  restriction  of  feeding 
to  specialized  kinds  of  food,  and  consequent  increase  in  the 
mechanical  cost  of  getting  it.  The  ocean  brings  food  to  an 
oyster;  a  cat  must  hunt  for  its  living.  Everywhere  the  dis- 
criminative appetite  is  the  expensive  one.  (d)  If  we  scru- 
tinize cases  in  which  feeding  appears  to  be  the  end  of  conscious 
effort,  we  find,  almost  if  not  quite  invariably,  that  the  very 
act  of  consciously  seeking  food  gives  to  nutrition  the  place 
of  means  to  some  experience  beyond  itself.  The  labor  move- 
ment illustrates  this  principle  on  a  large  scale.  Even  if  the 
central  stimulus  of  this  movement  could  be  identified  as 
hunger  (which  is  doubtful),  the  conscious  end  of  the  strug- 
gle is  home  life,  leisure,  culture,  the  education  of  children, 
free  participation  in  the  determination  of  one's  destiny,  (e) 
But  it  may  be  said  that  the  social  integration  of  men  has  as 
one  of  its  most  obviously  important  consequences  the  sta- 
bilizing of  the  food  supply  and  a  more  even  distribution  of  it. 
Civilization  will  soon  reach  a  point  at  which  famines  can  no 
longer  occur.  What,  it  may  be  asked,  is  the  meaning  of  the 
present  movement  for  agricultural  instruction,  and  indeed 
for  vocational  training  in  its  whole  extent,  if  not  just  this, 


MENTAL  FUNCTIONS  93 

that  men  want  enough  to  eat?  Here,  indeed,  is  excellent 
material  for  answering  the  question  what  mind  is  about  when 
it  seeks  food.  The  crucial  question  for  us  is  whether  the 
direction  of  the  mind's  movement  here  can  be  defined  as 
from  hunger  to  repletion.  Of  course  food  is  an  object  of 
conscious  desire.  So  is  getting  to  Albany  on  time  an  object 
of  desire  on  the  part  of  one  who  is  travelling  from  New  York 
to  Buffalo  by  way  of  the  New  York  Central.  The  road  to 
our  social  ends  certainly  takes  the  food-supply  route.  But, 
as  in  the  case  of  the  labor  movement,  social  food  seeking  that 
begins  instinctively  awakens,  sooner  or  later,  a  consciousness 
of  the  social  values  broadly  called  cultural,  and  these  it  is 
that  define  the  specifically  mental  destination  or  function. 

Turning  now  to  the  question  whether  reproduction  should 
be  accounted  a  mental  function,  we  find  the  course  of  evolu- 
tion not  at  all  ambiguous.  Reproduction  is  most  prolific  in 
the  lowest  ranges  of  life.  Mental  development  is  clearly 
correlated  with  decrease  in  the  birth  rate.  How  many  fac- 
tors are  involved  in  this  decrease  I  will  not  attempt  to  say, 
but  certainly  mind  is  one  of  them.  Herbert  Spencer  realized 
this  fact,1  though  he  did  not  bring  out  the  full  significance  of 
it.  John  Fiske's  two  essays  on  human  infancy2  carry  us 
much  farther.  Mind  individualizes  the  various  living  beings 
that  are  involved,  first  the  offspring  and  then  the  parents. 
The  obvious  mental  function  is  not  reproduction  of  existing 
types,  but  the  production  of  certain  new,  more  specialized 
types.  Mind  does  not  stimulate  reproduction  any  more  than 
it  stimulates  hunger;  it  does  not  increase  fertility  any  more 
than  it  increases  assimilation.  But,  just  as  mind  specializes 
foods  and  increases  the  cost  of  feeding,  so  it  individualizes 
living  beings  and  increases  the  cost  of  each  individual.  The 
whole  may  be  viewed  as  on  the  one  hand  an  increase  of  in- 
hibitions, and  on  the  other  hand  a  focalizing  of  dispersed  at- 
tention. In  short,  the  biological  functions  of  mind  can  be 
altogether  expressed  as  increase  in  the  range  of  objects  and 

1  'Principles  of  Biology,'  Part  VI.,  especially  Chs.  XII.  and  XIII. 

2  Reprinted  under  the  title,  'The  Meaning  of  Infancy,'  in  the  Riverside  Educa- 
tional Monograph  series,  Boston,  1909. 


94  GEORGE  A.  COE 

qualities  responded  to,  and  in  range  of  coordination  of  re- 
sponses. 

B.  Preferential  Functions. — Our  discussion  of  nutrition 
and  reproduction  has  already  brought  us  face  to  face  with 
conscious  preferences,  that  is,  mind  defining  its  own  direction. 
We  may  take  for  granted,  I  suppose,  that  satisfactions  are, 
in  general,  a  sign  of  unimpeded  mental  action,  and  that  we 
can  tell  one  another  about  our  satisfactions.  One  may,  in- 
deed, be  mistaken  as  to  what  one  likes,  that  is,  as  to  what  it 
is  in  a  complex  that  makes  it  likable,  but  such  mistakes  can 
be  discovered  and  corrected,  chiefly  by  further  communi- 
cation. The  functions  of  our  second  main  division,  then,  are 
always  qualitative  (implying  a  ' better  and  worse'),  and  they 
are  scientifically  known  through  communication  by  means  of 
language.  Thus  it  is  that  many  preferences  have  already 
been  successfully  studied,  such  as  color  preferences,  the  likes 
and  dislikes  of  children  with  respect  to  pictures  and  with  re- 
spect to  future  occupations,  merit  in  handwriting,  merit  in 
English  composition,  merit  as  a  psychologist,  the  comic, 
persuasiveness,  even  moral  excellence.1  Such  experimental 
studies  have  the  effect  not  merely  of  discovering  preferences, 
but  also  of  adding  precision  to  preferences  already  recorded 
in  the  world's  literature.  Would  that  a  Hollingworth  might 
have  been  present  throughout  human  evolution  to  record  the 
growth  of  human  preferences.  As  the  case  stands,  we  must 
combine  experiment  upon  present  preferences  with  the  less 
precise  study  of  life  as  reflected  in  literature,  art,  and  insti- 
tutions. 

Where  shall  we  look  for  a  basis  for  the  systematic  sub- 
division of  preferential  functions?  Suppose  we  compare 
early  types  of  reaction  with  late  ones,  say,  Thorndike's  pic- 
ture of  original  nature  with  value-analyses,  which  represent 
developed  interests.  Let  us  begin  with  the  fact  that  there  is 
satisfaction  in  merely  being  conscious.  To  be  conscious, 
then,  we  may  count  as  the  first  preferential  function.  Note, 
next,  that  satisfaction  attaches  to  mere  movement  of  atten- 

1H.  L.  Hollingworth  gives  a  list  of  'order  of  merit'  researches  in  'Experimental 
Studies  in  Judgment,'  Archives  of  Psychology,  New  York,  1913,  118  f. 


MENTAL  FUNCTIONS  95 

tion  from  one  object  to  another,  as  in  'love  of  sensory  life  for 
its  own  sake.'  May  we  not  say  that  a  second  preferential 
function  of  mind  is  to  multiply  its  objects?  A  third  appears 
in  the  preference  for  experiences  that  include  control  of  ob- 
jects. A  fourth  is  closely  related  thereto,  namely,  the  ar- 
rangement of  objects  in  systems — it  is  a  function  of  mind  to 
unify  its  objects.  This  is  seen  all  up  and  down  the  scale  from 
the  spontaneous  perception  of  spatial  figures  in  the  starry  sky 
to  the  ordering  of  an  argument. 

These  four  preferential  functions  appear  to  be  fundamen- 
tal, that  is,  not  further  analyzable.  If  we  turn,  in  the  next 
place,  to  the  usual  value  categories  to  see  whether  we  may 
not  find  further  unanalyzable  functions,  we  come  upon  the 
interesting,  not  to  say  strange,  fact  that  ethical,  noetic,  re- 
ligious and  even  economic  values  presuppose  a  function  that 
they  do  not  name.  Each  of  these  types  of  value  depends  upon 
the  existence  of  a  society  of  inter-communicating  individuals, 
yet  it  seems  not  to  have  occurred  to  anyone  to  include  a 
social  category — simply  and  specifically  social — in  discussions 
of  either  functions  or  values.  Should  not  the  fifth  prefer- 
ential function  in  our  list,  then,  be  the  function  of  being  social, 
of  having  something  in  common  with  another  mind,  in  short, 
of  communicating?  The  justification,  not  to  say  necessity, 
for  recognizing  a  simply  social  function  of  mind,  exists  not 
alone  in  the  social  presupposition  of  several  recognized  values, 
but  also  in  a  long  series  of  genetic  studies  which,  from  one 
angle  after  another,  have  revealed  the  fundamentally  social 
nature  of  consciousness.1 

There  remains  for  consideration  our  esthetic  experience. 
Doubtless  it  involves  functions  already  named,  particularly 

1  It  is  true  that  these  are  commonly  studies  of  content  rather  than  of  function, 
and  that  'P  and  'thou'  appear  therein  as  'idea  of  I*  and  'idea  of  thou.'  For  the  pur- 
poses of  merely  structural  analysis  this  is  doubtless  sufficient.  That  is,  structural 
analysis  as  such  has  no  place  at  all  for  the  experience  of  communication.  On  the 
other  hand,  communication  will  loom  large  in  any  adequate  general  analysis  of  mental 
functions.  In  an  article  'On  Having  Friends:  A  Study  of  Social  Values  '  (Jour.  Phil., 
XII.  (1915)*  iS5-i6i),  I  essay  a  functional  treatment  of  one  easily  accessible  social 
experience.  Satisfaction  in  having  a  friend  I  show  to  be  satisfaction  in  a  second 
experiencing.  Social  experience  like  this  is  distorted  whenever  attempts  are  made  to 
construe  it  without  the  -ing. 


96  GEORGE  A.  COE 

the  functions  of  unification  and  communication.  But  it 
seems  to  contain  also  an  attitude  somewhat  different  from 
those  already  named,  the  attitude  of  contemplation— the 
taking  of  satisfaction  in  objects  merely  as  there,  without  re- 
gard to  anything  further  that  may  happen  to  or  with  them. 
Hence  I  add  contemplation  to  the  list. 

The  preferential  functions,  then,  are  these: 

1.  To  be  conscious. 

2.  To  multiply  objects  of  consciousness. 

3.  To  control  objects,  oneself  included. 

4.  To  unify  objects,  oneself  included. 

5.  To  communicate,  that  is,  have  in  common. 

6.  To  contemplate. 

Some  omissions  from  this  list  require  explanation.  Play 
is  omitted  because  it  involves  a  complex  of  I  and  2,  generally 
3  also,  sometimes  all  six,  and  because  it  is  fully  exhausted 
therein.  Truth  is  omitted  because,  as  far  as  it  is  not  an  ab- 
straction from  actual  intellectual  functioning,  I  hold  it  to  be 
analyzable  without  remainder  into  functions  already  named, 
especially  4  and  5.1  No  ethical  function  appears  because  the 
three  objectives  that  it  includes — control,  unification,  sociali- 
zation— already  have  appropriate  recognition  in  the  list.2 
As  to  economic  value,  it  seems  to  be  exhausted  in  the  notion 
of  control  within  a  social  medium.  Finally,  religion  is  with- 
out a  place  in  the  list  because  it  offers  no  particular  value  of 
its  own.  Religion  is  not  coordinate  with  other  interests,  but 
is  rather  a  movement  of  reinforcement,  unification,  and  re- 
valuation of  values  as  a  whole,  particularly  in  social  terms.3 

It  will  be  asked,  no  doubt,  whether  the  functions  of  mind 
can  be  named  without  any  direct  reference  to  instinctive  de- 
sires. In  addition  to  what  has  already  been  said  concerning 
nutrition  and  reproduction — that  they  are,  so  to  say,  con- 
stants that  find  a  supply  at  every  level  of  mentality — it  may 
now  be  added,  as  a  general  truth,  that  mental  activity  upon 
the  objects  of  instinctive  desire  does  not  satisfy  the  desire  in 

1  Cf.  A.  W.  Moore,  'Truth  Value,'  Jour.  Philos.,  V  (1908),  429-436. 
1  Cf.  J.  H.  Tufts,  'Ethical  Value,'  Jour.  PhUos.,  V  (1908),  517-522. 
«G.  A.  Coe,  'Religious  Value,'  Jour.  Philos.,  V  (1908),  253-256. 


MENTAL  FUNCTIONS  97 

its  initial  form,  but  modifies  the  desire  itself.  For  example, 
what  has  at  first  only  a  derived  interest  as  means  to  something 
else  may  acquire  an  interest  of  its  own,  become  an  end.  This 
is  surely  the  way  that  science  has  come  into  being,  and  very 
likely  art  also.  The  evolution  of  parental  and  of  conjugal 
relations  offers  abundant  examples  of  the  truth  that  the  dis- 
tinctive work  of  mind  with  our  desires  is  to  differentiate  and 
recreate  them.  Our  list  of  mental  functions,  accordingly, 
need  not  specify  particular  desires,  but  only  the  primary 
ways  in  which  mind  works  among  them. 

A  question  may  arise,  also,  whether  higher  desires  or  ideal 
values  ought  not  to  appear  in  the  list.  Is  not  the  most  dis- 
tinctive achievement  of  mind  in  the  realm  of  desires,  it  may 
be  said,  the  mastery  of  certain  ones  in  the  interest  of  others? 
I  agree  that  'the  desires  of  the  self-conscious'  must  be  recog- 
nized as  having  a  character  of  their  own,1  and  that  a  list  of 
mental  functions  must  do  justice  to  them.  "The  valuation 
of  persons  as  persons  constitutes  a  relatively  independent 
type,  one  which  presupposes  a  differentiation  of  object  and 
attitude."2  The  list  as  it  stands,  however,  will  be  found  to 
do  justice  to  this  differentiation.  Here  are  self-control,  self- 
unification,  self-socialization,  with  the  implication  that  all 
this  applies  to  any  and  every  self,  both  actualized  selves  and 
ideal  selves. 

Finally,  inasmuch  as  no  pleasurable  sense-quality  of  ob- 
jects is  mentioned  in  the  list,  but  only  'objects,  oneself  in- 
cluded,' doubt  may  arise  whether  the  functions  here  named 
are  not  merely  formal  and  contentless.  Functions  would 
indeed  be  merely  formal  if  they  were  so  defined  as  to  imply 
indifference  to  the  specific  qualities  of  things.  'Pure  in- 
tellect' is  certainly  a  mere  abstraction,  never  a  function.  In 
a  list  of  'preferential  functions,'  however,  satisfactions  are 
everywhere  presupposed,  not  ignored.  Granted  both  pain- 
ful and  pleasurable  objects  as  data,  our  question  is  what 
mind  does  with  such  data.  Psychology  is  of  course  free  from 
the  old  hedonistic  fallacy  that  the  only  thing  we  can  do  with 

1  A.  O,  Lovejoy,  'The  Desires  of  the  Self-Conscious,'  Jour.  Philos.,  IV  (1907), 
29-39. 

2  W.  M.  Urban,  'Valuation,  its  Nature  and  Laws,'  London,  1909,  282;  see  also  269. 


98  GEORGE  A.  COE 

pleasures  is  to  seek  for  them,  and  that  the  only  thing  we  can 
do  with  pains  is  to  avoid  them.  What  we  try  to  do  in  the 
presence  of  such  data  is  to  control  and  organize  them,  sifting 
out  an  item  here,  deliberately  enlarging  an  item  there,  all  in 
the  interest  of  being,  so  to  say,  at  home  with  oneself  and  with 
one's  fellows.  In  short,  the  preferential  functions  here  named 
represent  minds  as  mutually  attaining  freedom  in  the  world 
as  it  is.  Such  minds  are  as  concrete  as  anything  can  con- 
ceivably be. 


COLOR  THEORY  AND  REALISM1 

BY  KNIGHT  DUNLAP 
The  Johns  Hopkins  University 

The  suggestion  made  by  McGilvary  concerning  a  possible 
color  theory  in  harmony  with  a  doctrine  of  sensational 
realism2  seems  to  me  very  important.  No  color  theory,  so 
far  as  I  am  aware,  has  attempted  to  do  more  than  satisfy 
the  psychological  requirements  (some  have  been  contented 
with  much  less) ;  but  it  is  possible  that  we  may  find  a  theory 
which  will  satisfy  both  the  psychological  requirements  and 
the  requirements  of  realism.  If  such  a  theory  be  found,  it 
will  be  a  matter  of  interest  and  importance. 

I  should  like  to  point  out,  in  the  first  place,  that  none  of 
the  prominent  theories  can  be  given  a  realistic  turn.  The 
Franklin  theory,  and  the  Hering  theory  with  its  variants, 
fall  short  on  the  psychological  side  in  so  many  places  (as,  for 
instance,  in  the  inability  to  account  for  the  perception  of  green 
without  red)  that  they  may  be  dropped  out  of  consideration. 
The  Hering  theory,  it  is  true,  would  perhaps  be  satisfactory 
to  the  realist,  if  it  were  psychologically  defensible;  but  the 
Franklin  theory  being  a  physiological  interpretation  of  the 
current  form  of  the  Young-Helmholtz  theory,  is  not  acceptable 
to  the  realist,  for  reasons  which  I  will  mention  below. 

The  Young-Helmholtz  theory,  as  at  present  held,  is 
satisfactory  to  the  psychologist,  largely  because  it  is,  as  I  have 
elsewhere  explained,3  merely  a  psychological  schematization, 
elastic  enough  to  take  in  all  of  the  accepted  data  of  color 
vision,  but  not  concerned  with  definite  hypotheses  in  the 
physiological  unknown. 

The  Young-Helmholtz  theory   assumes   red,   green,   and 

1  Written  in  1912,  but  withheld  from  publication  on  account  of  the  crowded 
condition  of  the  REVIEW. 

2  1912,  Philosophical  Review,  XXI.  (2),  171.     If  I  am  misrepresenting  Dr.  Me- 
Gilvary's  realism  (which  is  more  than  possible),  I  offer  my  apologies. 

5  'System  of  Psychology,'  p.  73,  footnote. 

99 


ioo  •        KNIGHT  DUNLAP 

bluish-violet  (indigo)  as  the  three  primary  colors;  not  because 
they  are  the  only  ones  on  which  the  theory  can  rest;  but 
because  it  happened  to  start  out  with  them  for  simplicity's 
sake,  and  has  as  yet  seen  no  sufficient  reason  for  changing. 

The  statement  of  Helmholtz  on  this  point  is  significant: 
"Der  Wahl  der  drei  Grundfarben  hat  zunachst  etwas  Will- 
kurliches.  Es  konnten  beliebig  jede  drei  Farben  gewahlt 
werden,  aus  denen  Weiss  zusammengesetzt  werden  kann. 
Young  ist  wohl  durch  die  Riicksicht  geleitet  worden,  dass  die 
Endfarben  des  Spectrum  eine  ausgezeichnete  Stellung  zu 
beanspruchen  scheinen.  Werden  wir  diese  nicht  wahlen, 
so  miisste  eine  der  Grundfarben  ein  purpurner  Farbenton  sein, 
und  die  ihr  entsprechende  Curve  in  Fig.  119  zwei  Maxima 
haben,  eines  im  Roth,  eines  im  Violett.  Es  ware  dies  eine 
complicirtere,  aber  nicht  unmogliche  Voraussetzung.  So  viel 
Ich  siehe,  giebt  es  bisher  keine  anderes  Mittel,  eine  der  Grund- 
farben zu  bestimmen,  als  die  Untersuchung  der  Farbenblin- 
den."1 

So  far,  no  exception  can  be  taken  to  Helmholtz.  But  in 
the  consideration  of  color  blindness,  he  made  a  mistake  which 
was  quite  excusable  at  the  time,  and  assumed  that  in  the 
ordinary  cases  of  dichromopsia  the  patient  sees  green  and 
violet,  since  the  natural  explanation  of  dichromopsia  seemed 
to  be  the  absence  of  one  of  the  three  processes.  Hence,  he 
found  no  reason  for  abandoning  Young's  primaries.  We  now 
know  (or  at  least  it  is  generally  believed)  that  the  two  colors 
seen  in  typical  dichromopsia  are  yellow  and  blue  or  some 
color  near  blue.  This  gives  us  the  alternative  of  abandoning 
Young's  set  of  primary  colors,  or  of  stating  the  parachro- 
mopsias  in  terms  other  than  those  of  absence  of  one  of  the 
three  processes.  The  latter  alternative  has  been  chosen  by 
adherents  to  the  Young-Helrnholtz  theory,2  and  for  psycho- 
logical purposes  is  quite  satisfactory  so  far.  It  might  be 
thought,  however,  from  the  statement  quoted  above,  that 

1  'Physiologische  Optik,'  Zweite  Abschnitt,  §  20  (pp.  292-293  in  the  first  edition). 

*  Opponents  of  the  three-color  theory  make  no  mention  of  this,  but  refute  the 
theory  in  its  older  form,  which  is  much  more  satisfactory  for  their  purposes.  So  far 
as  I  can  find,  the  only  modern  statements  of  the  theory  in  English  text-books  are  in 
Greenwood's  'Physiology  of  the  Senses'  and  my  'System  of  Psychology.' 


COLOR  THEORY  AND  REALISM  101 

Helmholtz  would  rather  have  considered  the  certification  of 
yellow-blue  dichromopsia  as  an  indication  that  the  three  prim- 
aries should  be  changed. 

The  acceptance  of  green  and  red  as  primaries  prevents  a 
realistic  interpretation  of  the  phenomena  of  color  vision,  since 
a  really  red  object  is  (probably)  seen  as  yellow  by  the  di- 
chromopsic  individual,  whereas  red  is  not  compounded  from 
yellow,  but  yellow  from  red,  according  to  the  theory.  There 
may  be  some  way  of  avoiding  this  difficulty,  but  it  seems  to 
me  that  the  acceptance  of  the  Young-Helmholtz  theory  in 
the  present  form,  or  of  the  Franklin  physiological  theory  based 
on  it,  entails  the  assumption  that  colors  are  purely  private 
content.  So  far  as  we  can  assume  psychologically,  some 
person  or  animal  might  see  as  blue,  or  as  any  other  color,  or 
even  as  the  note  b|?,  the  object  I  see  as  red. 

It  seems  to  be  possible  to  modify  the  Helmholtz  theory  in 
such  a  way  as  to  make  it  compatible  with  sensory  realism; 
and  possibly  the  modification  would  be  just  as  satisfactory 
psychologically.  We  might  eventually  have  to  assume  four 
colors  instead  of  three,  but  for  the  present  we  may  deal  with 
three,  with  the  addition  of  white  (gray).  This  addition  is 
necessary  because  of  the  fact  that  all  sorts  of  parachromopsias 
seem  to  agree  in  the  perception  of  white  in  quite  a  normal 
fashion  (or  at  least  it  is  now  generally  believed  that  this  is 
the  case). 

If  the  three  colors  are  yellow,  the  spectral  color  usually 
called  blue-green,  and  the  purple  complementary  to  green, 
the  theory  seems  to  work  out  very  well.  As  a  matter  of  fact, 
if  the  total  range  of  colors  be  studied  without  prejudice,  this 
triad  is  seen  to  be  at  least  as  satisfactory  (so  far  as  mere 
qualitative  comparison  goes),  as  any  other.  Let  us  call  the 
three  colors  yellow,  peacock,  and  mauve  (the  hues  commonly 
indicated  by  the  last  two  of  these  terms  are  near  enough  to 
the  colors  in  question  to  serve  the  purpose),  and  the  white  or 
gray  neutral.  We  may  then  use  the  letters  Y,  P,  M  and  N 
without  confusion.  Red  is  a  mixture  of  Y  and  M;  green  a 
mixture  of  Y  and  P;  blue  and  violet  are  mixtures  of  P  and 
M.  Practically  all  colors  contain  some  N.  Hence  the  fact 


102  KNIGHT  DUNLAP 

that  in  complete  achromopsia  only  N  is  seen,  in  certain  para- 
chromopsias  only  the  Fof  the  red  (Y  +  M)  combination,  and 
in  others  (possibly)  only  the  P  of  the  blue  and  violet  (P  +  M) 
combinations,  is  perceived,  is  quite  intelligible.  It  is  quite 
conceivable,  'in  other  words,  that  the  M  curve  of  the  'slow' 
end  of  the  spectrum  might  alone  be  lacking,  or  the  M  curve 
of  the  *  rapid'  end,  or  even  both  together.  Whether  the 
common  cases  of  dichromopsia  with  shortened  spectrum  are 
due  to  the  absence  of  the  M  curves  alone,  or  to  the  absence  of 
the  slow  M  curve  and  the  P  curve,  we  can  not  decide  from  the 
evidence  so  far.  In  the  cases  with  unshortened  spectrum, 
the  P  curve  alone  may  be  missing.  If  there  are  transitional 
cases  between  these  two  forms  of  dichromopsias  (which  some 
investigators  deny),  they  can  also  be  accommodated  in  this 
omnibus  theory;  for  it  may  be  pointed  out  that  there  are  end- 
less possibilities  of  difference  in  sensitiveness  of  the  processes 
present. 

The  occurrence  of  pure  white  in  normal  vision  is  to  be 
explained  by  the  facts  (which  are  established  regardless  of 
theory)  that  the  stimulation  of  any  color  process  renders  it 
progressively  less  sensitive.  If  the  eye  is  exposed  to  the 
influence  of  yellow  light,  it  sees  progressively  (expressed 
loosely)  less  and  less  yellow,  and  more  and  more  white.  The 
apparent  intensity  of  any  component,  in  other  words,  is 
relative  not  only  to  the  'natural  capacity'  of  the  eye,  but  also 
to  its  condition  at  any  moment;  and  this  condition  depends 
largely  on  preceding  stimulations.  We  have  to  assume  further 
that  any  mixture  of  light  rays  to  which  the  eye  has  become 
well  adapted,  will  therefore  not  stimulate  the  color  processes, 
although  it  will  stimulate  the  N  process.  It  is  a  significant 
fact  that  the  eye  becomes  as  well  adapted  to  yellow  gaslight 
or  to  the  bluish  light  of  the  mercury  vapor  arc,  as  to  daylight, 
if  it  is  subjected  to  one  of  these  stimuli  alone. 

There  is  however  a  further  necessary  statement,  which  is 
not  a  statement  of  fact  unless  our  hypothetical  theory  be 
true;  and  that  is,  that  the  three  processes  can  not  in  any  case 
be  simultaneously  stimulated.  Any  two  of  them  may  be 
set  in  action,  but  an  additional  stimulus,  adequate,  when 


COLOR  THEORY  AND  REALISM  103 

occurring  alone,  to  excite  the  third  process,  simply  has  an 
inhibitory  effect  on  the  first  two  (although  acting  as  an 
increased  stimulus  to  the  TV  process),  unless  this  third  stimulus 
becomes  relatively  more  intense  than  the  first  two,  in  which 
case  it  alone  is  effective,  the  other  two  serving  to  lessen  its 
specific  effect.  This  statement  rather  complicates  the  theory, 
but,  for  that  matter,  the  complication  indicated  occurs  in 
some  form  in  every  theory,  even  in  the  current  Young-Helm- 
holtz  theory.  While  this  realistic  color  theory  seems  to  me 
highly  interesting,  and  is  probably  just  as  workable  as  the 
accepted  form  of  the  Young-Helmholtz  theory,  I  should  not 
be  inclined  to  substitute  it  for  the  latter  unless  the  former 
theory  should  be  shown  to  be  the  psychologically  superior 
one.  A  sufficient  factor  of  community  in  the  world  of  objects 
may  be  given  in  the  relational  elements  alone,  and  I  think  we 
might  accept  this  point  on  a  basis  of  realism  rather  than  of 
idealism.  It  is  however,  well  to  bear  in  mind  the  realistic 
theory  of  color,  as  it  apparently  offers  welcome  possibilities 
of  psychological  research. 


POINT   SCALE   RATINGS   OF   DELINQUENT    BOYS 

AND  GIRLS1 

BY  THOMAS  H.  HAINES 

Bureau  Juvenile  Research,  Columbus,  Ohio 

The  Yerkes-Bridges2  point  scale  for  measuring  intelli- 
gence appeals  to  the  worker  in  the  province  of  the  standardi- 
zation of  the  development  of  human  intelligence  most  strongly 
as  a  very  useful  rationalization  of  the  Binet-Simon  method. 

1.  It  puts  the  whole  process  on  such  a  basis  that  is  is  con- 
stantly self-perfective, — the   norms    approach   the  reality  in 
direct  proportion  to  the  increase  in  number  of  records  of 
normal  children  summarized. 

2.  Another  advantage  is  that  it  becomes  a  simple  matter 
to  plot  curves  for  the  growth  of  intelligence  in  different  races, 
in  different  sexes,  and  in  different  classes  of  society  in  the 
same  locality.     All  resulting  curves  and  tabulations,  being 
made    by    the    same    examinational    methods,    are    directly 
comparable. 

3.  It  is  not  to  be  denied,  also,  that  the  point  scale  method 
of  rating  intelligence  overcomes  some  arbitrariness  in  method, 
in  that  it  allows  the  individual  to  make  his  credits  anywhere 
along  the  line  of  some  twenty  tests,  whereas  the  Binet  method 
makes  the  passing  of  a  given  year  depend  upon  a  fixed  stan- 
dard, passing  four  out  of  five  given  tests. 

4.  Partial  credit  given  for  partial  results  also  commend 
this  method,  as  for  example  in  'words  given  in  three  min- 
utes,' 'three  words  used  in  one  sentence,'  'arrangement  of 
weights,'  and  'counting  backward  from  20  to  I.' 

It  was  a  very  fortunate  feature  of  the  plan  of  the  origi- 
nators of   the  point  scale,  that  they  pursued    the  natural 

1  Read  before  the  American  Psychological  Association,  at  a  meeting  at  Phila- 
delphia, December  29,  1914. 

*  See  'The  Point  Scale.    A  New  Method  for  Measuring  Mental  Capacity,'  by 
Robert  M.  Yerkes  and  J.  W.  Bridges,   The  Boston  Medical  and  Surgical  Journal, 
Vol.  CLXXL,  Number  23,  December  3,  1914,  pp.  857-866. 
104 


POINT  SCALE  RATINGS  105 

method  of  development,  and  relied  almost  entirely  upon  the 
Binet  material  and  methods.  Nineteen  of  the  twenty  point 
scale  tests  are  Binet  tests.  Analogies  are  extra. 

This  makes  it  a  very  simple  matter  to  conduct  the  two 
examinations  on  the  same  person  at  the  same  time,  or 
rather  to  secure  both  a  Binet  and  point  scale  rating  of 
a  given  person  from  one  examination.  One  has  simply  to 
follow  the  order  of  the  point  scale  sheet.  When  this  is 
complete,  it  is  only  a  matter  of  half  a  dozen  short  tests 
to  complete  the  Binet  rating.  This  practice  has  been  pur- 
sued by  the  author  in  examining  two  hundred  delinquents  in 
industrial  schools  in  Ohio.  The  idea  in  mind,  in  the  begin- 
ning, was  to  try  out  the  point  scale  in  comparison  with  the 
Binet-Simon  method,  to  see  what  it  was  worth,  as  it  was 
frankly  recognized  that  the  data  summarized  in  the  point 
scale,  so  far,  from  normal  children,  are  rather  limited,  as  com- 
pared with  those  from  the  use  of  the  Binet  scale. 

It  was  soon  apparent  that  results  from  the  two  methods 
showed  a  very  close  parallel,  the  point  scale  results  tending  a 
little  higher,  as  would  be  expected  with  abnormal  adolescent 
minors,  because  of  the  wider  opportunities  offered  for  securing- 
credits,  for  any  given  year  of  intelligence  age.  But  the 
paralleling  is  so  close  in  the  low  grade  morons,  and  the  agree- 
ment is  so  close  between  the  two  methods  in  excluding  in- 
telligence defect  in  the  higher  grade  delinquents,  that  dis- 
parity between  the  two  ratings  seemed  at  once  to  afford 
reasonable  ground  for  doubt  as  to  the  value  of  the  Binet 
findings. 

We  formed,  therefore,  a  class  of  doubtful  cases, — cases  in 
which  Binet  rating  made  the  child  less  than  twelve  years  old 
mentally,  and  point  scale  credits  were  beyond  twelve  years. 
The  close  correlation  of  results  by  the  two  scales  is  the  first 
result  of  interest  in  this  work.  The  second  is  the  value  of 
the  point  scale  as  a  check  upon  the  Binet  scale  in  determining 
the  line  between  intelligence  defect  and  normal  intelligence. 
At  the  best,  it  is  a  delicate  matter  to  decide  between  a  high 
grade  moron  and  one  who  has  no  intelligence  defect,  and  each 
examiner  must  develop  his  own  standards.  But  where  a 


106  THOMAS  H.  RAINES 

boy  makes  11.4  years  Binet  and  80  points  by  point  scale,  or 
14  years,  it  is  certainly  safe  to  consider  his  Binet  record  as  in 
some  measure  accidental,  and  that  he  is  more  likely  to  make 
good,  than  the  boy  whose  Binet  is  1 1.4  years,  and  whose  point 
scale  is  71  points,  or  n.6  years.  The  latter  seems  much  more 
likely  to  prove  himself  a  high  grade  moron,  to  have  an  irre- 
mediable defect  in  equipment  on  the  side  of  intelligence.  Of 
course,  even  here  there  is  doubt.  The  point  scale  is  a  method 
contributing  to  the  finer  shading  of  our  doubts,  and  the  more 
precise  statement  of  intelligence  defects. 

In  scoring  by  the  Binet  method,  we  adopted  the  common 
procedure  of  requiring  four  credits  to  pass  a  given  year,  mak- 
ing the  highest  so  passed  a  basal  year,  and  allowing  one  year 
additional  for  each  five  credits.  Half  credits  were  often 
given,  as  e.  g.,  in  two  definitions  superior  to  use  in  the  nine- 
year  tests,  copying  one  design  in  the  ten-year  tests,  or  giving 
solution  to  one  problem  in  twelve-year  tests.  Mentality  was 
reckoned  to  tenths  of  years.  In  estimating  mental  age  by 
the  point  scale,  the  spirit  of  the  method  was  violated  to  this 
extent,  that  we  assumed  the  lines  of  the  curve  between  each 
two  consecutive  years  to  be  straight,  and  we  set  down  the 
equivalent  to  a  point  rating,  in  years,  reckoned  to  the  nearest 
tenth  of  a  year. 

The  classification  adopted  in  the  first  two  hundred  cases 
examined,  one  hundred  at  the  Girls'  Industrial  School,  and 
one  hundred  at  the  Boys'  Industrial  School,  resulted  in  the 
following  grouping.  The  average  mentalities  are  given  for 
each  group. 

GIRLS. 

1.  34  low  and  medium  morons,  ranging  from  8  to  10.5  years 

mentally. 

Binet   average,    9.4   years.     Point    scale    average  =  54.5 
points,  or  9.1  years. 

2.  24  high-grade  morons,  ranging  from  10.5  years  up. 
Binet    average,    10.9    years.     Point    Scale    average  =  70 

points,  or  11.5  years. 

3.  13  doubtful  cases. 

Binet  average,   11.5   years.     Point  scale  average  =  80.1 
points,  or  14  years. 


POINT  SCALE  RATINGS 


107 


29  no  intelligence  defect. 

Binet,  22  =  12  yrs.  -f 
5  =  12    " 
2  =  12     "    - 


Point  scale  average  =  84 
points. 


BOYS. 

1.  2  high-grade  imbeciles,  each  making  32  points  =  6.6  years, 

point  scale. 

2.  40  medium  and  low-grade  morons. 

Binet   average,   9.4   years.      Point   scale   average  =  56.2 
points,  or  9.5  yrs. 

3.  25  high-grade  morons. 

Binet  average,   10.9  years.      Point  scale  average  =  81.2 
points,  or  14.5  years. 

4.  20  doubtful  cases. 

Binet  average,   11.4  years.     Point  scale  average  =  81.2 
points,  or  14.5  years. 

5.  13  no  intelligence  defect. 

Binet  6=12  yrs.  +  Point  scale  average  of  the  seven 
I  =  12  yrs.  84.6  =15  years  +  2j  points. 

Six  of  the  thirteen  were  less  than  two  years  retarded. 

The  mean  or  average  variations  from  these  averages  so 
far  as  calculable,  both  for  years,  and  for  points,  are  embodied 
in  the  following  table: 


Av.  Binet 

M.V. 

Av. 
P.S. 

M.V. 

Equivalent 
Years 

M.V. 

GIRLS 
Low  and  medium  morons  . 
High  morons    

94  yrs. 
IO.Q  yrs. 

.39  yrs. 
.4.3  yrs. 

54-5 
7O 

5-5  = 

-z.c  = 

9.1  yrs. 
ii  yrs. 

.58  yrs. 
.32  vrs. 

Doubtful  intell.  def  
No  intell.  def  

1  1.$  yrs. 
22  are  12  -f-  yrs. 

.24  yrs. 

80.  1 
«1 

3-5  = 

7.C    = 

14  yrs. 
it;  yrs.+ 

BOYS 

Low  and  medium  morons  . 
High-grade  morons  
Doubtful  

5  are  12  yrs. 
2  are  12  —  yrs. 

94  yrs. 
10.0  yrs. 
11.4.  yrs. 

.50  yrs. 
.42  yrs. 
.20  yrs. 

|6.2 
67 

81  ? 

5-3    = 

3-5  = 

2.Q  = 

2  pts. 

9.5  yrs. 
1  14  yrs. 
14..  c  yrs. 

.64  yrs. 
.24  yrs. 

No  defect 

•*  -t-  /iu 
o  are  1  2  yrs  -p 

84.6 

27  — 

1C  vrs  -4- 

I    is    12  yrs. 

2  pts. 

These  figures  demonstrate  the  point  scale,  at  the  present 
state  of  development,  to  be  quite  as  accurate  a  means  of 
measuring  the  intelligence  of  high  grade  defectives  as  is  the 


loS  THOMAS  H.  RAINES 

Binet  scale.  In  the  groups  directly  comparable,  by  mean 
variations,  we  find  the  low  and  medium  morons,  both  boys 
and  girls,  yielding  considerably  larger  mean  variations  for 
point  scale  equivalents  in  years,  and  the  high  grade  morons, 
both  sexes,  yielding  considerably  smaller  mean  variations 
for  point  scale  equivalents  in  years.  One  could,  of  course, 
throw  these  comparisons  either  way  by  manipulating  the 
data.  The  effort  in  grouping  was  to  give  equal  weight  to 
each  set  of  figures.  That  this  was  done  with  fair  success  is 
indicated  by  the  close  approximation  to  each  other,  of  the 
average  mental  ages,  obtained  by  the  two  methods,  in  each 
of  these  two  groups  for  both  sexes. 

The  mean  variations  from  the  point  scale  averages,  for 
the  four  groups,  for  each  sex,  indicate  that  we  have  made  the 
three  highest  groups  of  about  the  same  ranges  of  mentality, 
whereas  the  lowest  has  nearly  twice  the  range.  The  low  and 
medium  grade  morons  could  readily  be  set  apart  into  two 
groups  each,  having  a  range  equivalent  to  that  of  the  high 
grades  morons.  The  M.  V.  of  each  group  would  lower  ac- 
cordingly. It  is  a  great  satisfaction  to  feel  that  we  have 
even  a  tentative  means  of  assessing  the  intelligence  develop- 
ment, between  ten  and  fifteen  years,  in  the  normal  child. 
Small  and  insignificant  as  are  the  point  differences  in  these 
years,  the  point  scale  begins  to  let  in  the  light  upon  these 
differentiations,  which  the  Binet  scale  has  left  in  the  dark. 
When  more  data  are  collected,  qualitative  or  analytic  studies 
of  the  differences  in  the  point  scale  findings  with  children 
rating  within  these  years,  both  normal  and  abnormal,  may 
be  expected  to  yield  significant  results,  —  significant  for 
diagnosis  of  the  mentality  of  the  exceptional  child. 

In  view  of  the  disparity  of  the  results  obtained  by  the 
two  methods,  in  our  group  of  '  doubtful  intelligence  defect,' 
two  things  at  once  occur  to  one.  (i)  It  will  be  interesting  to 
note  the  future  history  in  the  particular  cases,  to  see  whether 
such  a  doubtful  child  proves  himself  to  be  11.5  years  mentally 
as  per  Binet  or  14  years  as  per  point  scale.  There  must 
remain  a  blot  upon  his  intelligence,  until  he  disproves  it,  for 
he  is  likewise  retarded  by  both  ratings  as  compared  with 


POINT  SCALE  RATINGS  109 

the  group  above.  It  is  rare  for  members  of  this  group  to 
achieve  the  82  points  of  15  years,  while  the  higher  group 
averages  84  points. 

(2)  The  other  matter  in  regard  to  this  disparity  holds  in 
regard  to  the  'no  defect'  group  also.  In  both  groups  and 
for  both  sexes  the  points  attained  by  point  scale  rating  cor- 
respond to  higher  years  on  the  point  scale  curves,  than  are 
attained  by  the  Binet  rating.  One  cannot  avoid  the  sus- 
picion that  the  numbers  of  normal  cases  so  far  rated  in  these 
higher  years  by  the  point  scale,  may  be  so  few  and  so  ex- 
ceptional that  we  have  averages  which  are  too  low  for  given 
years,  and  that  more  work  with  normals  will  bring  these 
figures  higher.  The  close  correspondence  between  the  two 
ratings  for  the  lower  groups  suggests  this.1  A  thousand 
normal  children,  ten  to  fifteen  years  old,  rated  and  grouped 
by  point  scale,  would,  in  any  event,  bring  needed  light  in  this 
region.  The  same  results  studied  analytically  would  be  of 
great  service  in  furthering  insight  into  mental  organization 
and  development  in  late  childhood  and  adolescence. 

1  Professor  Yerkes  states  that  point  scale  and  Binet  ratings,  resulting  from  his 
own  examinations  of  more  than  fifty  normal  children,  show  that  the  Binet  ratings 
for  children  below  the  mental  age  of  eight  are  too  high,  and  for  children  above  the 
mental  age  of  eight  they  are  too  low.  Professor  Thorndike  comes  to  a  similar  view 
by  taking  Dr.  Goddard's  results  of  the  examinations  of  two  thousand  school  children 
in  Vineland,  New  Jersey,  and  working  out  the  averages  and  median  values.  For 
Thorndike's  results  see  the  Psychological  Clinic,  December  15,  1914. 


A  PRELIMINARY  STUDY  OF  THE  DEFICIENCIES  OF 
THE  METHOD   OF   FLICKER  FOR  THE 
PHOTOMETRY  OF  LIGHTS  OF  DIF- 
FERENT COLOR1 

BY  C.  E.  FERREE  AND  GERTRUDE  RAND 

Bryn  Mawr  College 

SYNOPSIS 

A  satisfactory  method  of  photometry  should  combine  the  following  features. 
(i)  It  should  enable  one  to  detect  small  differences  in  luminosity  and  to  reproduce 
results  for  a  given  observer  with  a  small  mean  variation  and  for  a  number  of  observers 
with  a  comparatively  small  mean  variation.  That  is,  the  method  should  possess  an 
adequate  degree  of  sensitivity.  (2)  It  should  be  known  either  to  possess  of  itself  logical 
sureness  of  principle  or  its  results  must  agree  in  the  average  with  those  of  some  method 
which  can  be  shown  to  have  this  sureness  of  principle.  The  method  of  flicker  probably 
satisfies  the  first  of  these  requirements  better  than  the  equality  of  brightness  method. 
It  does  not,  however,  possess  of  itself  the  needed  sureness  of  principle,  nor  have  its 
results  been  shown  to  agree  in  the  average  with  any  method  which  is  accorded  sureness 
of  principle.  Points  are  enumerated  in  the  paper  appended  which  raise  doubt  with 
regard  to  the  correctness  of  the  photometric  balance  obtained  by  the  method  of  flicker. 
Only  one  of  these  is  discussed,  namely,  the  influence  of  the  time  element  in  the  exposure 
of  the  eye  to  the  lights  to  be  compared.  With  regard  to  this  point,  it  is  shown  from 
experimental  data  (i)  that  the  sensations  aroused  by  lights  differing  in  color  value  rise 
to  their  maximum  brightness  at  different  rates;  and  (2)  that  the  single  exposures  used 
in  the  method  of  flicker  are  much  shorter  than  is  required  for  these  sensations  to  rise 
to  their  full  value.  The  eye,  therefore,  is  very  much  underexposed  to  its  stimulus  by 
the  method  of  flicker.  That  is,  the  rate  of  succession  used  in  the  method  of  flicker  is 
too  fast  for  the  single  impressions  to  arouse  their  maximum  effect  in  sensation  and  too 
slow  for  the  successive  impressions  to  add  or  summate  as  much  as  they  would  need 
to  do  to  rise  to  their  full  value  or  perhaps  even  to  a  higher  value  than  would  be  given 
by  the  individual  exposures.  Only  one  other  possibility  for  a  correct  balance  remains, — 
equality  is  attained  at  some  value  lower  than  the  full  value.  This  can  not  be  assumed, 
however,  without  violating  well-known  laws  relating  to  the  factors  which  influence 
persistence  of  vision. 

The  principal  point  of  discussion,  then,  is  to  what  degree  it  should  be  held  that  the 
difference  in  lag  between  the  sensations  aroused  by  the  single  exposures  used  in  the 
method  of  flicker  is  obliterated  in  a  succession  of  exposures.  Broadly  considered,  three 
positions  are  possible  with  regard  to  the  point  for  the  rates  of  succession  that  are 
employed  in  the  method  of  flicker,  (i)  The  difference  is  not  obliterated  at  all.  In 
this  case  the  photometric  balance  should  deviate  from  the  true  balance  in  direct  pro- 

1  Paper  read  by  C.  E.  Ferree  at  the  Philadelphia  section  of  the  Illuminating 
Engineering  Society,  January  16,  1914. 
1 10 


FLICKER  PHOTOMETRY  m 

portion  to  the  difference  in  lag  for  the  single  exposures.  (2)  The  difference  is  in  part 
obliterated,  but  it  is  still  present  to  a  degree  which  renders  the  method  untenable  for 
precise  work.  And  (3)  the  difference  is  entirely  obliterated  or  so  nearly  so  as  to  be  of 
no  practical  consequence  to  the  validity  of  the  method.  The  second  is  approximately 
the  position  taken  in  this  paper.  The  following  evidence  is  offered  in  support  of  this 
position,  (a)  At  high  intensities  of  light  the  writers  get  by  the  method  of  flicker  a 
deviation  from  the  true  photometric  balance,  as  determined  by  the  equality  of  bright- 
ness method,  in  a  direction  which  corresponds  to  the  difference  in  lag  between  these 
colors  at  high  intensities  as  determined  both  in  their  own  laboratory1  and  by  Broca 
and  Sulzer.  (£)  At  low  intensities  they  get  a  difference  in  lag  for  the  colors  which  is  in 
the  same  direction  as  the  deviation  obtained  by  Ives  and  Luckiesh  at  low  intensifies 
(the  reverse  Purkinje  effect),  (c)  A  change  in  the  relative  lengths  of  exposure  to  the 
two  lights  in  the  method  of  flicker  produces  a  deviation  from  the  equality  of  brightness 
balance  which  again  corresponds  in  direction  to  the  changes  that  are  produced  in  the 
sensations  aroused  by  the  single  exposures  when  similar  changes  are  made  in  the 
relative  lengths  of  exposure.  And  (d)  determinations  made  at  several  intensities  of 
light  by  the  method  of  flicker  show  a  deviation  from  the  equality  of  brightness  balance 
which  is  many  times  the  smallest  difference  in  brightness  that  can  be  detected  by  the 
method.  Moreover,  in  their  own  results  the  writers  find  that  these  deviations  in  every 
case  correspond  to  the  difference  in  lag  given  by  lights  of  the  same  order  of  magnitude 
of  intensity,  so  far  as  can  be  judged  from  the  determinations  of  lag  that  have  been  made 
up  to  this  time.  When,  however,  determinations  have  been  made  on  a  larger  number 
of  observers,  individual  differences  may  be  found  in  the  amount  and  distribution  of  lag 
just  as  they  have  been  found  in  the  amount  and  direction  of  the  deviation  of  the  flicker 
from  the  equality  of  brightness  balance.  Later  in  the  interests  of  a  fairer  comparison 
the  writers  hope  to  make  in  every  case  compared  the  determination  of  lag  and  the  photo- 
metric determinations  on  the  same  observer. 

The  writers  have  preferred  to  call  the  work  of  which  this 
paper  is  a  brief  report  a  preliminary  study  for  the  following 
reasons,  (i)  Only  one  of  the  points  directly  pertaining  to 
the  method  of  flicker  that  should  be  investigated  has  been 
taken  account  of  in  the  work.  And  (2)  to  complete  the  chain 
of  evidence  needed  for  this  point,  a  more  especially  directed 
and  perhaps  more  careful  determination  should  be  made 
than  has  yet  been  done  of  the  time  required  for  visual 
sensations  colored  and  colorless  to  rise  to  their  maximum  of 
intensity.  Such  a  study  with  especial  reference  to  the  needs 
of  photometry  is  now  in  progress  in  our  laboratory,  but  is  as 
yet  unfinished.2 

1  See  this  paper,  footnote  I,  pp.  125-130. 

2  In  the  work  now  in  progress  in  our  laboratory,  attention  will  be  paid  to  the 
following  points.     In  case  of  colors,  care  will  be  taken  to  use  lights  of  a  small  range  of 
wave-length.     The  intensities  of  the  lights  used  will  be  specified  photometrically  and 
radiometrically.     The  white  light  will  in  addition  be  specified  either  spectro-photo- 
metrically  or  spectro-radiometrically.    For  the  sake  of  the  comparisons  needed  in 


H2  c.   E.  FERREE  AND  GERTRUDE  RAND 

A  satisfactory  method  of  photometry  should  combine  the 
following  features,  (i)  It  should  enable  us  to  detect  small 
differences  in  luminosity  and  to  reproduce  our  results  for  a 
given  observer  with  a  small  mean  variation  and  for  a  number 
of  observers  with  a  comparatively  small  mean  variation. 
That  is,  the  method  should  possess  an  adequate  degree  of 
sensitivity.  (2)  It  should  be  known  either  to  possess  of  itself 
logical  sureness  of  principle,  or  its  results  must  in  the  average 
agree  with  those  of  some  method  which  can  be  shown  to 
possess  this  sureness  of  principle.  Methods  having  these 
features  have  been  developed  for  the  photometry  of  colorless 
light.  The  problem  of  the  photometry  of  colored  light, 
however,  has  presented  great  difficulty. 

METHODS  OF  PHOTOMETERING  COLORED  LIGHT. 
The  methods  for  photometering  colored  light  may  be 
grouped  under  two  headings:  the  direct  methods  and  the  in- 
direct methods.  In  the  former  class  we  have  the  method  of 
direct  comparison  or,  as  it  is  sometimes  called,  the  equality  of 
brightness  method.  Of  the  latter  class  the  method  of  flicker 
has  received  the  greatest  amount  of  attention  and  has  been  the 
most  favored.  It  will  be  the  purpose  of  this  paper  (i)  briefly 
to  compare  the  relative  advantages  and  disadvantages  of 
the  method  of  flicker  and  the  equality  of  brightness  method 
with  regard  to  sensitivity;  (2)  to  show  that  the  method  of 
flicker,  so  far  as  it  has  been  developed  up  to  the  present  time, 
does  not  seem  to  possess  of  itself  the  sureness  of  principle 
needed  to  meet  the  requirements  of  a  satisfactory  method; 
and  (3)  to  show  that  as  yet  its  results  have  not  been  found 
satisfactorily  to  agree  in  the  average  with  those  of  any  method 
which  can  be  shown  to  have  this  sureness  of  principle.  In  a 

the  photometric  work,  all  determinations  for  lights  differing  in  composition  will  be 
made  at  the  different  intensities  employed  with  stimuli  equalized  photometrically. 
Comparative  results  will  be  obtained  for  the  same  observers  for  the  best  of  the  methods 
already  in  use,  and  three  new  methods  will  be  introduced.  In  part,  results  will  be 
obtained  for  observers  who  have  also  been  employed  in  the  work  on  the  method  of 
flicker.  The  work  will  be  done  for  different  intensities  of  light,  and  both  under 
dark  and  light  room  conditions.  In  a  survey  of  the  work  done  up  to  the  present 
time,  one  can  not  help  but  note  that  too  little  care  has  been  taken  to  observe  even 
some  of  the  most  essential  of  the  above  conditions. 


FLICKER  PHOTOMETRY  "3 

later  paper  a  new  method  of  photometry  will  be  described  which 
possesses  approximately  as  high  a  degree  of  sensitivity  for  color 
work  as  the  method  of  flicker  and  gives  results  which  agree 
much  more  closely  in  the  average  with  those  obtained  by  the 
equality  of  brightness  method.  The  second  of  the  above  points 
will  be  shown  as  follows.  It  will  be  pointed  out  that  at  the  rate 
of  speed  at  which  the  impressions  are  given  in  the  method  of 
flicker,  the  eye  is  very  much  underexposed  to  its  stimulus.  It 
can  reasonably  be  assumed  that  this  underexposure  causes  a 
reduction  of  the  intensity  of  the  sensation,  and  should  lead, 
therefore,  to  a  false  estimation  of  the  brightness  of  the  colors. 
In  fact,  at  the  rate  of  rotation  of  the  exposure  apparatus 
required  for  lights  of  the  order  of  intensity  employed  in 
practical  work,  this  reduction  produces  for  the  observers  we 
have  used  an  effect  similar  to  the  Purkinje  phenomenon.1 
At  least  a  deviation  from  the  equality  of  brightness  values 
is  found  in  our  results  for  such  intensities  which  accords  well 
with  the  Purkinje  phenomenon.  That  is,  reds  and  yellows 
are  underestimated  in  brightness,  and  blues  and  greens  are 
overestimated.  And  (b)  it  will  be  shown  that  flicker  itself, 
the  phenomenon  on  which  the  equalization  at  the  photo- 
metric screen  is  based,  is  subject  to  variations  depending  upon 
a  number  of  factors  the  effect  of  which  has  not  in  all  cases  been 
adequately  studied  and  in  some  cases  not  even  recognized. 
An  investigation  of  one  of  these  alone,  the  effect  of  varying 

1  We  do  not  mean  to  draw  too  close  an  analogy  here  between  the  effect  on  the 
brightness  of  sensation  produced  by  keeping  the  intensity  of  light  constant  and  reduc- 
ing the  time  of  exposure  of  the  eye  to  the  light,  and  the  effect  produced  by  keeping  the 
time  of  exposure  of  the  eye  constant  and  reducing  the  intensity  of  the  light  employed 
(the  Purkinje  phenomenon).  In  attempting  to  interpret  the  effect  produced  by  the 
short  exposures  used  in  the  method  of  flicker,  our  data  should  be  taken  primarily 
from  the  results  showing  the  relative  rise  of  sensation  to  its  maximum  for  white  light 
and  lights  of  the  different  colors.  (See  discussion  of  the  development  time  of  sensa- 
tion, pp.  118-130).  It  is  quite  possible  and  in  fact  quite  probable  from  Broca  and 
Sulzer's  results,  for  example,  that  for  a  part  of  the  upward  course  blue  and  green 
rise  faster  than  red,  and  conversely  for  a  part  of  the  course  red  rises  faster  than  blue 
and  green.  (Yellow  was  not  used  by  Broca  and  Sulzer.)  The  results  of  Broca  and 
Sulzer  are  cited  on  this  point,  not  by  any  means  because  their  method  of  making 
the  determination  is  the  freest  from  criticism  of  any  that  have  yet  been  used,  but 
because  they  alone  have  attempted  to  plot  the  comparative  curves  for  the  different 
colors  and  white  light  at  different  points  from  the  threshold  to  the  maximum. 


114  C.  E.  FERREE  AND  GERTRUDE  RAND 

the  ratio  of  the  time  of  exposure  of  the  eye  to  the  lights  to  be 
compared,  is  enough  to  lead  one  seriously  to  question  whether 
the  method  of  flicker  can  be  safely  used  in  the  work  of  hetero- 
chromatic  photometry,  at  least  not  without  calibration,  and 
perhaps  not  without  an  amount  of  calibration  which  is  in 
itself  prohibitive  of  the  use  of  the  method  in  practical  work. 
The  third  point  will  be  covered  in  the  following  way.  (i)  It 
will  be  pointed  out  that  the  only  method  that  has  thus  far 
been  used  as  a  standard  with  which  to  compare  the  method 
of  flicker  has  been  the  equality  of  brightness  method.  The 
selection  of  this  method  as  a  standard  has  been  recommended 
among  others  by  Whitman,  Wilde,  and  Schenck,  and  a  com- 
parison of  the  results  of  the  two  methods,  more  or  less  com- 
plete, has  been  made  by  a  number  of  experimenters.  And  (2) 
it  will  be  shown  both  from  our  own  work  and  from  a  very  great 
preponderance  of  the  work  done  by  others  who  have  made  the 
comparison,  that  the  results  by  the  method  of  flicker  do  not 
agree  in  the  average  with  those  obtained  by  the  equality  of 
brightness  method;  and,  therefore,  that  justification  for  the 
adoption  of  the  method  of  flicker  can  not  yet,  at  least,  be 
fairly  claimed  through  its  agreement  in  result  with  the 
equality  of  brightness  method. 

The  Equality  of  Brightness  Method. — With  regard  ,to  sensi- 
tivity in  the  photometry  of  lights  of  different  color,  the 
equality  of  brightness  method  has  the  following  disadvan- 
tages, (i)  Small  differences  in  luminosity  can  not  be  de- 
tected because  the  actual  difference  present  is  masked  by 
the  difference  in  color  quality.  (2)  Results  for  a  given 
observer  can  not  be  reproduced  within  a  small  limit  of 
variation,  because  the  ability  to  do  this  in  turn  presupposes 
the  ability  to  detect  small  differences  which,  as  has  just  been 
stated,  can  not  be  done.  (3)  Results  can  not  be  reproduced 
from  observer  to  observer  within  a  small  limit  of  variation 
because  (a)  the  sensitivity  to  color  varies  more  among  ob- 
servers than  does,  for  example,  the  sensitivity  to  brightness, 
hence  there  is  a  variable  amount  of  the  disturbing  factor  of 
color  present  for  different  observers;  and  (b)  because  the 
standard  or  pattern  for  the  judgment  of  equality  differs 


FLICKER  PHOTOMETRY  115 

more  from  individual  to  individual  when  the  factor  of  color  is 
present  than  when  it  is  not.  That  is,  in  any  photometric 
judgment  the  observer  must  decide  for  himself  what  he  will 
call  equality  and  make  all  his  judgments  conform  to  this 
pattern  or  standard.  When  color  is  present  to  interfere  with 
the  judgment  of  equality,  the  selection  of  this  standard  varies 
more  for  different  observers  than  it  does  when  no  color  is 
present.  With  regard  to  all  the  points  on  which  sensitivity 
depends,  therefore,  the  equality  of  brightness  method  may 
be  said  to  possess  a  low  degree  of  sensitivity. 

The  Method  of  Flicker. — The  method  of  flicker  possesses 
greater  sensitivity  than  the  equality  of  brightness  method. 
That  is,  smaller  differences  in  the  luminosity  of  the  photo- 
metric surfaces  can  be  detected,  and  the  judgment  of  equality 
is  surer  and  more  reproducible.1  This  is  because  the  disturb- 
ing factor  of  color  difference  in  the  impressions  to  be  compared 
is  eliminated  from  the  judgment.  That  is,  instead  of  being 
given  simultaneously,  the  stimuli  are  given  in  succession  and 
at  such  a  rate  that  all  color  differences  between  them  disap- 
pear, and  the  brightness  impressions  are  permitted  to  develop 
in  sensation  unobscured  by  differences  in  color  quality. 

The  use  of  the  phenomenon  of  flicker  to  detect  a  difference 
in  brightness  between  two  illuminated  surfaces  can  best  be 
understood  possibly  by  considering  the  phenomena  that  take 
place  when  successive  impressions  of  colored  and  colorless 
light  are  made  upon  the  retina  at  different  rates  of  speed. 
When  the  retina  is  exposed  successively  to  colorless  lights 
differing  in  brightness,  the  following  phenomena  take  place. 
When  the  rate  of  succession  is  low,  the  impressions  remain 

1  This  higher  degree  of  reproducibility  can  be  claimed  perhaps  only  for  the  judg- 
ments given  by  a  single  observer.  It  does  not  seem  to  obtain  to  any  considerable 
extent,  so  far  as  results  are  available  for  comparison,  when  results  are  compared  from 
observer  to  observer.  For  example,  in  a  group  of  eighteen  observers  Ives  gets  differences 
as  great  as  159  per  cent,  for  .481  /i,  114  per  cent,  for  .498  /*,  26  per  cent,  for  .518/1. 
18  per  cent,  for  .537*1;  13  per  cent,  for  .556/4;  10  per  cent,  for  .576/0;  28  per  cent,  for 
•595  M,  65  per  cent,  for  .615  /i;  86  per  cent,  for  .635  /i;  and  122  per  cent,  for  .655  p. 
The  percentage  of  average  variation  from  the  mean  for  these  observers  is  17  per  cent, 
for  .481  /i;  134  per  cent,  for  .498  /i;  6  per  cent,  for  .518  /t;  3  per  cent,  for  .537/4;  2.75 
per  cent,  for  .556/1;  2.2  per  cent,  for  .576/1;  5.4  per  cent,  for  .595  //;  9.5  per  cent,  for 
.615/1;  13-2  per  cent,  for  .635/1;  and  19.3  per  cent,  for  .655/1.  (Philos.  Mag.,  1912, 
24,  Ser.  6,  pp.  853-863.) 


n6  C.  E.  FERREE  AND  GERTRUDE  RAND 

more  or  less  separate  and  distinct.  At  rates  higher  than  thisr 
we  have  in  order  Fechner's  colors,1  flicker,  and  the  fusion  of 
the  two  impressions  into  a  uniform  gray.  When  the  eye  is 
exposed  successively  to  colored  and  colorless  light,  the  follow- 
ing phenomena  take  place.  At  low  rates,  we  have  again  the 
more  or  less  separate  successions  of  the  two  impressions.  At 
rates  slightly  higher  than  this,  we  have  first  a  phenomenon 
that  may  be  called  by  analogy  color  flicker,  and  then  an  inter- 
mingling of  color  and  brightness  flicker.  At  still  higher  rates 
we  have  color  fusion,  brightness  flicker,  and  complete  color 
and  brightness  fusion.  Thus,  both  in  case  of  colored  and 
colorless  light,  brightness  flicker  seems  to  be  a  phenomenon 
due  solely  to  the  succession  at  certain  rates  of  speed  of  im- 
pressions differing  in  luminosity  or  brightness.  Moreover,, 
the  phenomenon  is  very  sensitive  to  changes  in  the  luminosity 
of  the  successive  impressions.  That  is,  a  very  slight  change 
in  one  of  the  impressions  will  produce  flicker  when  there  is  no 
flicker,  or  will  cause  a  noticeable  change  in  its  amount  when 
there  is  flicker.  Flicker  thus  becomes  a  very  sensitive  means 
of  detecting  brightness  difference.  This  sensitivity,  however,, 
is  not  so  great  in  case  of  colored  as  it  is  in  case  of  colorless 
light.  It  would  in  fact  in  all  probability  be  very  low  were  it 
not  for  the  fortunate  fact  that  color  fusion  takes  place  at  a 
very  much  lower  rate  of  succession  than  brightness  fusion. 

Concerning  the  ease  and  sureness  of  making  the  judgment,, 
then,  the  case  with  regard  to  the  method  of  flicker  may  be 
summed  up  as  follows:  By  giving  the  impressions  to  be 
compared  to  the  retina  successively  at  a  certain  rate  of  speed, 
the  disturbing  element  of  color  difference,  which  so  interferes 
with  the  detection  of  brightness  difference  when  the  im- 
pressions are  given  simultaneously,  is  eliminated,  and  the 
phenomenon  of  brightness  flicker  stands  out  clearly  in  a  field 
uniform  as  to  color  quality.  That  is,  by  using  a  method  of 
successive  impressions  we  have  succeeded  in  eliminating  the 

1  Fechner's  colors  are  best  observed  when  the  successions  are  made  by  rotating 
discs  made  up  of  white  and  black  sectors,  or  by  discs  specially  constructed  for  the 
purpose.  This  phenomenon  occurs  at  a  rate  of  speed  near  the  upper  limit  required 
to  give  separate  impressions,  and  consists  of  impressions  of  color  mingled  with  the 
more  or  less  separate  impressions  given  by  the  white  and  black  sectors. 


FLICKER  PHOTOMETRY  n7 

feature  that  renders  the  comparison  of  the  brightness  of  the 
simultaneous  impressions  so  difficult  to  make,  namely,  the 
difference  in  color  quality  between  the  impressions  to  be 
compared.  The  judgment,  then,  is  easy,  and  the  principle 
on  which  the  equalization  is  based  seems  to  be  clear.  The 
method  has  come  to  have  many  supporters,  but  other  things 
besides  the  sureness  of  judgment  must  be  taken  into  account. 
This  brings  us  to  a  consideration  of  our  second  point,  namely, 
the  method  of  flicker  when  applied  to  the  photometry  of 
lights  of  different  color  does  not  seem  to  possess  the  sureness 
of  principle  needed  to  meet  the  requirements  of  a  satisfactory 
method.  We  have  two  reasons  for  making  this  assertion. 
In  the  first  place,  as  we  have  already  stated,  at  the  rate  of 
speed  at  which  the  impressions  are  given  in  the  method  of 
flicker,  the  eye  is  very  much  underexposed  to  its  stimulus. 
And  in  the  second  place,  flicker,  the  phenomenon  on  which 
the  equalization  is  based  at  the  photometric  surface,  is  subject 
to  many  variations  depending  upon  a  number  of  factors  the 
bearing  of  which  on  the  application  of  the  phenomenon  to 
photometry,  has  not  in  all  cases  been  adequately  studied,  and 
in  some  cases  not  even  recognized.  A  few  of  these  may  be 
suggested  in  passing,  (i)  The  intensity  of  illumination  and 
the  influence  it  exerts  on  the  speed  of  alternation  that  has  to  be 
used  in  order  to  give  the  method  maximum  sensitivity. 
(2)  The  different  rates  of  speed  required  for  the  fusion  of  the 
different  colors,  and  the  varying  lower  limit  this  difference 
puts  upon  the  rates  of  speed  that  can  be  used.  (3)  The  effect 
of  the  saturation  of  the  colors  used  on  the  fusion  rate.  (4) 
The  effect  of  field  size.  (5)  The  effect  of  the  ratio  of  the  time 
of  exposure  of  the  eye  to  the  lights  to  be  compared;  etc.  A 
better  knowledge  than  we  now  have  of  the  effect  of  these 
factors  is,  the  writers  believe,  of  fundamental  importance  in 
the  employment  of  the  phenomenon  of  flicker  in  the  photom- 
etry of  lights  of  different  colors.  At  a  later  date  they  hope 
to  report  the  results  of  a  systematic  study  of  these  factors. 
In  the  present  paper,  the  effect  of  only  one  of  them  will  be 
considered,  namely,  the  ratio  of  the  time  of  exposure  of  the 
eye  to  the  lights  to  be  compared.  An  investigation  of  this 


uS  c.  E.  FERREE  AND  GERTRUDE  RAND 

point  alone  is  enough  to  lead  one  seriously  to  question  whether 
the  method  of  flicker  can  safely  be  used  in  the  work  of  hetero- 
chromatic  photometry,  at  least  not  without  calibration,  and 
perhaps  not  without  an  amount  of  calibration  which  is  in 
itself  prohibitive  of  the  use  of  the  method  in  practical  work. 

THE  ACTION  OF  LIGHT  ON  THE  EYE  UNDER  THE  CONDITIONS 
IMPOSED  BY  THE  METHOD  OF  FLICKER. 

Both  of  the  above  points  will  probably  be  more  easily 
understood  if  a  brief  consideration  is  given  to  the  way  the 
eye  responds  to  colored  and  colorless  lights  when  the  im- 
pressions are  given  to  it  in  the  manner  they  are  given  in 
the  method  of  flicker.  The  eye  is  not  an  ideal  sense  organ, 
that  is,  it  does  not  respond  at  once  with  its  full  intensity  of 
sensation  at  the  beginning  of  stimulation,  nor  does  the  sensa- 
tion cease  with  the  cessation  of  stimulation.  It  takes,  for 
example,  an  interval  of  time  for  the  sensation  proper  to  a 
given  stimulus  to  rise  to  its  maximum;  and  also  an  interval 
to  die  away  after  the  stimulation  has  ceased,  depending  for 
its  length  upon  several  factors.1 

The  interval  of  time  required  for  a  sensation  to  rise  to  its 
maximum  will  be  called  in  this  paper  the  development  time  of 
sensation.  Plateau  in  18342  first  expressed  the  belief  that 

1  There  are  two  phases  to  this  after-effect,  positive  and  negative.    The  positive 
alone  concerns  us  here.    In  this  phase,  which  is  often  called  the  persistence  of  vision, 
the  original  sensation  tends  to  persist  in  its  original  color  and  brightness.     More 
accurately  described,  however,  it  rapidly  loses  in  color  and  rapidly  darkens.     In  the 
negative  phase  there  is  a  brightness  reversal,  that  is,  what  is  light  in  the  original 
sensation  becomes  dark,  and  the  color  changes  to  the  complementary  color.     The 
negative  phase  is  much  longer  than  the  positive.    The  length  of  the  positive  depends 
upon  many  factors:  the  intensity  of  the  stimulus,  the  time  of  exposure  of  the  eye 
to  the  stimulus,  the  state  of  adaptation  of  the  eye,   the  general   illumination   of 
the  field  of  vision,  the  brightness  of  the  local  preexposure  and  post-exposure,  etc. 
Unless  the  eye  is  put  under  very  especial  conditions  of  stimulation,  the  duration  of  the 
positive  phase  is  very  short  indeed,  in  fact,  momentary.     For  a  further  discussion  of 
this  point  with  reference  to  the  method  of  flicker,  see  appendix. 

2  As  early  as  the  time  of  Bacon  it  was  noted  that  there  is  a  period  of  inertia  in 
vision.     ("At  in  visu  (cujus  actio  est  pernicissima)   liquet  etiam  requiri  ad  eum 
actuandum  momenta  certa  temporis:  idque  probatur  ex  iis,   quae  propter  motus 
velocitatem  non  cernunter;  ut  ex  latione  pilae  ex  sclopeto.     Velocior  enim  est  praeter- 
volatio  pilae,  quam  impressio  speciei  ejus  quae  deferri  poterat  ad  visum"."— 'Novum 
Organum,'  lib.  II.,  Aph.  XLVI.).     Later  Beudant  ('Essai  d'un  Cours  Elementaire 


FLICKER  PHOTOMETRY  119 

color  sensation  does  not  come  at  once  to  its  maximum.  He, 
and  later  Fick1  in  1863,  showed  that  when  a  sector  of  white 
paper  passes  very  rapidly  only  once  before  the  eye  it  looks 
to  be  a  dark  gray.  With  the  experiments  of  Exner  in  1868, 
the  work  of  determining  the  development  time  of  visual 
sensation  was  definitely  begun.  Different  methods  of  making 
the  determination  have  been  used  by  different  investigators, 
and  different  results  have  been  obtained.  There  is,  however, 
among  the  different  results  a  certain  amount  of  agreement. 
At  least  the  order  of  magnitude  of  the  development  time  can 
be  fixed  within  certain  limits.  The  chief  points  of  interest 
in  these  investigations  have  been  (i)  to  compare  the  develop- 
ment time  of  the  different  sensations  of  color  with  each  other 
and  with  that  of  colorless  sensation;  and  (2)  to  determine 
whether  the  intensity  of  the  stimulus  has  any  effect  upon 
the  development  time.  All  who  have  made  the  comparison 
have  found  that  each  of  the  color  sensations  has  a  development 
time  different  from  the  colorless  sensations;  all  with  the  excep- 
tion of  Diirr  and  Berliner,  that  each  of  the  colors  has  a  different 
development  time;  and  all  with  the  exception  of  Diirr,  that  an 
increase  of  intensity  shortens  to  some  extent  the  development 
time  of  all  sensations. 

A  table  (Table  I.)  has  been  prepared  showing  the  develop- 
ment time  obtained  by  each  of  these  men  for  the  different 

et  General  des  Sciences  Physique:  Partie  Physique,'  p.  489,  3 me  edition)  also  stated 
that  an  object  which  moves  with  extreme  rapidity  before  the  eye  is  not  perceived 
because  impressions  are  not  made  on  the  eye  instantly.  Plateau  ('  Nouveaux  Memoirs 
de  1'Academie  Royale  des  Sciences  et  Belles  Lettres  de  Bruxelles,'  1834,  8,  p.  53) 
made  the  observation  that  when  a  bit  of  white  paper  passes  very  rapidly  before  the 
eye,  it  appears  not  white  but  gray.  He  was  the  first  to  express  the  belief  that  color 
sensation  also  does  not  come  at  once  to  its  maximum  of  intensity.  Swan  (Trans. 
Roy.  Soc.  Edinb.,  1849,  16,  pp.  581-603)  observed  that  the  "light  of  the  sky  seen 
immediately  over  a  ball  in  its  descent  through  the  air,  seemed  less  bright  than  at  those 
parts  of  the  retina  where  the  action  of  light  had  not  been  interrupted  by  the  passage 
of  the  dark  body";  and  conducted  some  experiments  to  determine  the  intensity  of 
light  sensation  with  short  exposures.  Exposing  the  eye  to  lights  of  different  intensities 
for  intervals  ranging  from  i/ioo  to  1/16  of  a  second,  colorless  'lights  of  different 
intensity  produce  like  portions  of  their  total  effect  on  the  eye  in  equal  times.'  While 
he  does  not  directly  determine  the  interval  required  for  the  light  sensation  to  come  to 
its  maximum,  he  estimates  it  from  the  results  of  his  experiments  with  short  exposures 
to  be  about  i/io  of  a  second. 

:Fick,  A.     Archiv  fur  Anatomic  und  Physiologie,  1863,  p.  739. 


120  C.  E.  FERREE  AND  GERTRUDE  RAND 

TABLE  I 

SHOWING  A  COMPARISON  OF  THE  DEVELOPMENT  TIME  OF  VISUAL  SENSATION  WITH 
THE  AVERAGE  TIME  OF  EXPOSURE  OF  THE  EYE  TO  ITS  STIMULUS  USED  IN  OUR 
EXPERIMENTS  WITH  THE  METHOD  OF  FLICKER. 


Sensation 

Development  Time 

Average  Time  of 
Exposure  of  Color  by 
Method  of  Flicker 

Exner1 

1868 

White 

5  intensities: 

.0178   sec.,   when 

Kunkel2     

1874 

Different  colors 

.118-2.87  sec- 
.05  7-.  133 

the    value    of    the 
colored    sector   was 
180°. 

Charpentier*  

1887 
1896 

White, 
White, 

5  intensities 
.OI4-.049 
5  intensities 

Durr5  

1902 

White, 

.090-.  148 
2  intensities: 

N^artius* 

IQO2 

Different  colors 
White 

.266 

,;54i    . 

6  intensities: 

.0213    sec.,   when 

Broca  and  Sulzer7 
McDougall.8  .. 

1903 
IQO4. 

Different  colors 
White 

Different  colors 
White 

.OI3-.093 

.020-.090 

8  intensities: 
.03  1  -.125 
.07  -.125 
12  intensities: 

the    value    of    the 
colored  sector  ran- 
ged from  45°-3i5°- 

Biichner9  

1006 

Different  colors 
White 

.049-.  2 
.100-.  108 
3  intensities: 

Berliner10  

I  QO7 

Different  colors 

.033-.230 
.no 

*Exner,  S.,  'Ueber  die  zu  einer  Gesichtswahrnehmung  nothige  Zeit.,'  Sitzungs- 
berichte  der  Kaiserlichen  Akademie  der  Wissenschaften,  Math.-Phys.  Classe,  1868, 
58,  pp.  601-632. 

2  Kunkel,  A.,    'Ueber  die  Abhangigkeit  der  Farbenempfindung  von  der  Zeit/ 
P finger's  Arckiv,  1874,  p,  p.  197. 

3  Charpentier,  'Sur  la  periode  d'addition  des  impressions  illuminismes,'  Corn-pies 
Rendus  Societe  de  Biologie,  1887,  4,  pp.  192-194. 

4  Lough,  'The  Relations  of  Intensity  to  Duration  of  Stimulation  in  Our  Sensations 
of  Light,'  PSYCHOLOGICAL  REVIEW,  1896,  j,  pp.  484-492. 

6  Durr,  E.,  'Ueber  das  Ansteigen  der  Netzhauterregung,'  Philosophische  Studien, 
1901-1903,  18,  pp.  215-273. 

6  Martius,  G.,  'Ueber  die  Dauer  der  Lichtempfindungen,'  Beitrdge  zur  Psychologie 
und  Philosophie,  Leipzig,  1902,  I,  Heft  3. 

7  Broca,  A.,  and  Sulzer,  D.,  Comptes  Rendus  der  Seances  de  VAcademie  des  Sciences, 
1902,  134,  pp.  831-834;  1903,  137,  pp.  944-946;  977-979;  and  1046-1049. 

•McDougall,  W.,  'The  Variation  of  the  Intensity  of  Visual  Sensation  with  the 
Duration  of  the  Stimulus,'  British  Journal  of  Psychology,  1904-1905,  I,  pp.  151-189. 

9  Biichner,  M.,  'Ueber  das  Ansteigen  der  Helligkeitserregung,'  Psychologische 
Studien,  1906-1907,  2,  pp.  1-29. 


FLICKER  PHOTOMETRY  121 

colored  and  colorless  sensations;  and,  for  comparative  pur- 
poses, the  average  exposure  time  that  was  used  in  our  experi- 
ments for  all  the  colors  in  the  determination  of  their  bright- 
ness by  the  method  of  flicker.  In  choosing  this  time  of  ex- 
posure for  the  method  of  flicker,  in  order  to  secure  for  the 
method  the  greatest  possible  sensitivity,  we  used  the  slowest 
rate  of  succession  of  colored  and  colorless  sectors  that  could 
be  employed. 

An  inspection  of  this  table  will  show  that  while  the  results 
for  the  development  time  of  sensation  differ  quite  a  little 
among  themselves,  they  agree  in  one  very  important  partic- 
ular, namely,  they  are  all  much  greater  than  are  the  intervals 
that  are  used  in  the  longest  exposures  that  are  permissible 
by  the  method  of  flicker.  That  is,  by  the  method  of  flicker, 
the  eye  is  very  much  underexposed  to  its  stimulus.  The 
effect  of  this  under  exposure  is  obviously  to  cause  a  reduction 
in  the  intensity  of  sensation.  That  is,  the  rate  of  succession 
of  impressions  used  in  the  method  of  flicker  is  too  fast  for  the 
single  impressions  to  arouse  their  maximum  effect  in  sensa- 
tion and  too  slow  for  the  successive  impressions  to  add  or 
summate  as  much  as  they  would  need  to  do  to  cause  the  in- 
tensity of  the  sensation  aroused  by  each  light  to  rise  to  its 
full  value,  or  perhaps  even  to  rise  to  a  higher  value  than 
would  be  given  by  the  individual  exposures.  In  fact  as  will 
be  shown  in  an  appendix  to  this  paper  the  sensation  can 
not  be  expected  to  rise  to  its  full  value  through  summa- 
tion if  the  Talbot-Plateau  law  be  true,  however  rapid  is 
the  rate  of  succession  of  the  individual  impressions  (see  ap- 
pendix). Even  when  a  rate  is  reached  at  which  complete 
fusion  takes  place,  both  for  the  color  and  brightness  com- 
ponents in  sensation,  there  is  according  to  the  Talbot- 

10  Berliner,  'Der  Ansteig  der  reinen  Farbenerregung  im  Sehorgan,'  Psychologische 
Studien,  1907,  5,  pp.  91-155. 

W.  Swan  in  an  article  entitled  'On  the  Gradual  Production  of  Luminous  Impres- 
sions on  the  Eye;  Part  II.,  being  a  description  of  an  instrument  for  producing  isolated 
luminous  impressions  on  the  eye  of  extremely  short  duration,  and  for  measuring  their 
intensity,'  Trans.  Roy.  Soc.  Edinb.,  1861,  2,  pp.  33-40,  has  described  a  very  ingenious 
but  complicated  apparatus  for  getting  short  periods  of  stimulation  of  the  retina,  but 
apparently  neither  he  nor  any  one  else  has  ever  used  the  apparatus  described. 


122  C.  E.  FERREE  AND  GERTRUDE  RAND 

Plateau  law,  a  reduction  in  the  intensity  of  each  sensation 
which  is  the  same  as  would  be  gotten  were  the  intensity  of 
each  light  to  be  reduced  in  proportion  to  the  time  of  ex- 
posure of  that  light  to  the  total  time  of  exposure  of  both 
lights,  and  no  further  increase  in  the  rate  of  succession  pro- 
duces any  change  in  the  effect.1  The  possibility  then  of  the 
sensations  which,  as  is  shown  by  the  work  on  development 
times,  are  unequal  for  the  single  exposures  used  in  the 
method  of  flicker,  reaching  equality  by  rising  to  their  full 
value  seems  to  be  ruled  out.  In  terms  of  the  Talbot-Plateau 
law  they  could  not  reach  their  full  intensity  through  an  effect 
of  summation,  however  fast  the  rate  of  succession  be  made, 

1  Ewald  ("Versuche  zur  Analyse  der  Licht-  und  Farbenreaktionen  eines  Wirbel- 
losen  "  (Daphnia  pulex),  Ztschr.f.  Psychol.  u.  Physiol.  d.  Sinnes.,  1914,  48,  pp.  285-325; 
and  "The  Applicability  of  the  Photochemical  Energy  Law  to  Light  Reactions  in 
Animals,"  Science,  1913,  38,  pp.  236-238)  has  made  an  interesting  contribution  with 
regard  to  the  effect  of  the  intermittent  action  of  light  on  the  eye  which  it  may  not  be 
out  of  place  to  mention  here.    The  facetted  eye  of  the  daphnia  was  used  in  his  experi- 
ments.   When  exposed  to  light  this  eye  responds  by  turning  towards  the  light,  and 
when  lights  of  different  intensities  are  used  it  turns  towards  the  stronger  light.     After 
having  determined  the  sensitivity  of  this  response  to  difference  in  intensity  of  light  by 
exposing  the  eye  to  a  number  of  lights  of  different  intensities  acting  continuously  on 
the  eye,  he  undertook  to  make  a  comparison  of  the  effect  of  light  acting  continuously 
and  intermittently.    The  intermittence  was  gotten  by  rotating  a  sectored  disc  in  front 
of  one  of  the  lights.     The  lights  were  so  chosen  that  the  same  amount  of  energy  acted 
upon  the  eye  in  a  given  unit  of  time  from  both  the  continuous  and  intermittent  sources. 
That  is  if  a  ratio  of  total  open  to  closed  sector  of  the  value  l/io  was  used,  the  light  in 
front  of  which  these  sectors  were  rotated  was  made  ten  times  as  intense  as  the  light 
acting  continuously.    The  sectored  disc  was  then  rotated  at  different  speeds.     When 
a  speed  of  30  revolutions  per  second  was  attained  the  eye  remained  stationary.     That 
is  at  this  speed  of  rotation  the  two  lights  produced  equal  effects  on  the  eye, — which  is, 
of  course,  no  more  than  a  demonstration  of  the  Talbot-Plateau  law  for  the  primitive 
eye.     But  when  the  speed  was  made  slower  than  this,  the  eye  invariably  turned  towards 
the  light  which  was  acting  continuously.    That  is  when  the  rate  at  which  the  im- 
pressions were  given  to  the  eye  was  made  slower  the  result  was  to  weaken  the  effect 
on  the  eye  even  though  the  same  amount  of  light  was  received  by  the  eye  in  a  unit  of 
time  in  both  cases.     Ewald's  results  show  then  that,  so  far  as  the  primitive  eye  is 
concerned,  when  light  impressions  are  given  to  the  eye  at  certain  high  rates  of  succession 
(analogous  to  the  fusion  rates  for  the  human  eye)  there  is  a  reduction  in  the  amount  of 
response  aroused  which  is  the  same  as  would  be  produced  were  the  intensity  of  the 
light  reduced  by  an  amount  proportional  to  the  ratio  of  the  time  of  exposure  to  the 
light  to  the  total  time  of  the  observation;  and  when  they  are  given  to  the  eye  at  rates 
slower  than  these  the  effect  on  the  eye  is  the  same  as  if  the  light  acting  on  it  had  been 
still  further  reduced  in  intensity. 


FLICKER  PHOTOMETRY  123 

let  alone  attain  it  at  the  rates  which  are  employed  in  the 
method  of  flicker.1 

1  There  seems  to  be  only  one  other  possibility  that  the  method  of  flicker  should 
give  the  true  photometric  balance  between  lights  of  different  color  values,  namely,  that 
the  sensations  aroused  should  reach  equality  at  some  value  lower  than  the  full  value. 
That  this  is  extremely  improbable  is  shown  by  the  following  consideration.    The 
weaker  sensation  or  the  sensation  which  has  the  slower  rate  of  development  for  a  single 
exposure  would  have  to  rise  in  value  because  of  summation  effect  resulting  from  the 
succession  of  exposures  until  it  became  equal  to  the  stronger  sensation.     To  produce 
any  effect  of  summation  each  individual  impression  would  have  to  last  over  in  sensation 
until  the  next  impression  of  its  kind  is  received  which,  since  the  impressions  alternate, 
would  be  the  next  impression  but  one.     And  to  produce  the  particular  effect  required 
here,  not  only  would  each  excitation  have  to  last  over  until  the  next  one  is  aroused,  but 
the  weaker  one  would  have  to  last  over  more  strongly  than  the  stronger  one,  else  the 
effect  of  the  summation  would  not  be  to  produce  the  gain  of  the  weaker  on  the  stronger 
which  is  required  to  bring  the  two  to  the  true  photometric  balance.     That  is,  the 
advocate  of  this  point  of  view  would  say  that  even  though  for  the  single  exposure  one 
color  is  weighted  more  than  the  other,  the  effect  of  this  is  obliterated  in  a  succession  of 
impressions  and  the  two  rise  to  equal  value,  because  the  weaker  sensation  would  carry 
over  more  strongly  hence  would  gain  more  relatively  in  the  process  of  summating  than 
would  the  stronger  sensation.     This  is  not  at  all  in  accord  with  the  experimental  evi- 
dence available  at  this  time  on  the  relation  of  the  positive  after-effect  or  persistence  of 
sensation  to  the  original  sensation.     Goldschmidt  ("Quantitive  Untersuchungen  iiber 
positive  Nachbilder,"  Psych.  Studien,  1910,  6,  pp.  159-252)  and  others  show,  for  ex- 
ample, that  the  stronger  the  original  sensation,  the  more  strongly  does  it  tend  to 
carry  over  after  the  light  is  cut  off.     Goldschmidt  also  concludes  from  his  experiments, 
which  is  a  very  important  point  for  this  discussion,  that  the  tendency  of  the  sensation 
to  carry  over  is,  so  far  as  its  brightness  is  concerned,  independent  of  the  color.     That 
is,  suppose  that  a  photometric  balance  was  obtained  for  green  and  red  lights  of  com- 
paratively high  intensities  by  the  method  of  flicker.     Then  according  to  Broca  and 
Sulzer's  curves,  also  the  results  obtained  in  this  laboratory,  green  would  attain  to  a 
higher  brightness  value  for  the  single  exposure  than  would  be  attained  by  red.     Hence  if 
green  is  not  to  be  overestimated  by  the  method  of  flicker,  red  must  carry  over  more 
strongly  as  the  impressions  succeed  each  other  than  does  green,  and  thus  make  up  by 
a  summation  effect  the  deficiency  shown  in  the  single  exposure.     But  according  to 
Goldschmidt's  results  this  greater  tendency  to  carry  over  could  not  be  assumed  for 
red,  either  because  of  its  color  value  or  because  of  its  weaker  intensity,  and  there  is 
no  other  aspect  of  the  sensation  which  could  have  any  bearing  on  the  question  in  hand. 
Moreover,  this  hypothesis  is  rendered  still  more  untenable  by  the  experimental  fact 
that  the  situation  at  low  intensities  is  reversed.     That  is,  at  low  intensities  red,  as 
shown  by  the    curves  for  difference  in  lag  (see  Fig.  2,  p.  127),  attains  to  a  higher 
value  than  green  for  the  single  exposure.     Then  if  red  is  not  to  be  overestimated 
by  the  method  of  flicker  and  in  direct  proportion  to  the  values  given  to  the  two  sensa- 
tions in  the  single  exposure,  green  must  be  carried  over  more  strongly  in  the  succession 
of  impressions  than  is  red.     The  explanation  of  both  of  these  points  would  require 
not  only  that  the  color  value  of  the  stimulus  exerts  an  influence  on  the  carrying  over 
of  the  brightness  aspect  of  the  sensation,  but  that  this  influence  reverses  in  passing 
from  high  to  low  intensities.     For  a  discussion  of  how  highly  improbable  it  is  for  the 
rates  of  succession  used  in  the  method  of  flicker  that  one  impression  could  last  over 
until  the  next  impression  but  one  is  received  in  any  amount  that  could  be  of  con- 
siderable consequence  to  the  method,  see  appendix. 


124  C.  E.  FERREE  AND  GERTRUDE  RAND 

It  seems  fair  to  conclude,  then,  that  instead  of  getting  by 
the  method  of  flicker  the  sensations  that  should  be  aroused  by 
the  lights  with  which  we  are  working,  we  get  sensations  of  lower 
intensity.  But  it  may  be  asked  what  if  there  is  a  reduction  of 
the  intensity  of  the  impressions  received?  Equalization  is  all 
we  are  working  for  and  the  intensity  of  both  impressions  is 
reduced.  Is  it  not  possible,  therefore,  to  find  a  ratio  of  time  of 
exposure  to  each  light  such  that  the  amount  of  reduction  in 
the  intensity  of  both  impressions  will  be  equal  ?  This  would  be 
comparatively  simple  if  the  rate  of  development  for  all  the 
colored  were  the  same  as  for  all  the  colorless  sensations.  The 
intervals  of  exposure  could  be  made  equal  as  is  ordinarily  done 
when  sectored  discs  are  used  and  as  apparently  must  be  done 
when  the  exposures  are  given  by  means  of  a  rotating  prism. 
But  the  development  time  for  color  sensation  is  not  the  same 
as  for  colorless  sensation,  and,  moreover,  the  consensus  of  evi- 
dence is  that  the  rate  of  development  is  not  the  same  for  any 
two  of  the  color  sensations.  Thus  from  the  standpoint  of  the 
unequal  reduction  in  intensities  produced  by  the  method  of 
flicker,  the  task  of  selecting  a  proper  ratio  of  exposure  time  of 
colored  to  colorless  light,  in  case  of  the  different  colors,  is  one 
that  requires  a  great  deal  of  accurate  knowledge  if  the  method 
is  to  have  the  sureness  of  principle  needed, — more,  the  writers 
think,  than  we  now  possess.1 

1  One  scarcely  needs  point  out  in  this  regard  that  there  is  apparently  no  point 
in  the  intensity  scale  for  which  a  given  reduction  in  intensity  for  colored  light  gives 
the  same  change  in  luminosity  in  sensation  that  it  does  for  white  light.  Beginning 
with  the  spectrum  of  fully  saturated  colors  and  comparing  the  effect  of  reduction  by 
equal  amounts  of  colored  and  white  lights  equal  in  photometric  value,  the  blues  and 
greens  are  found  not  to  decrease  in  luminosity  so  fast  as  the  white  light,  and  the  reds 
and  yellows  are  found  to  decrease  faster.  Or  as  the  phenomenon  is  ordinarily  ex- 
pressed, there  is  a  relative  lightening  of  the  blues  and  greens  and  a  relative  darkening 
of  the  reds  and  yellows.  Nor  is  the  phenomenon  of  unequal  change  confined  to  the 
lower  intensities.  It  is  more  striking  for  these  intensities,  but  it  occurs  also  for  the 
higher  intensities.  This  conclusion  is  drawn  from  the  statement  made  by  several 
writers  that  beginning  with  the  spectrum  of  fully  saturated  colors  and  increasing  the 
intensity  of  light,  all  the  colors  are  found  to  tend  towards  white,  and  in  so  doing  to 
change  their  luminosities  at  different  rates.  (For  example,  see  Helmholtz,  H.,  'Ueber 
Hrn.  D.  Brewster's  neue  Analyse  des  Sonnenlichts,'  Pogg.  Ann.,  1852,  86,  p.  520;  also 
Handbuch  der  physiologischen  Optik,  zw.  Aufl.,  1896,  pp.  465-466;  Chodln,  A.,  'Ueber 
die  Abhangigkeit  der  Farrbenempfindungen  von  der  Lichtstarke,'  Sammlung  physio- 
logischer  Abhandlungen  von  Preyer,  1877,  I,  p.  33  if.;  Briicke,  E.,  'Ueber  einige 


FLICKER  PHOTOMETRY  125 

We  have  discussed  here,  moreover,  the  effect  of  underex- 
posure at  only  one  rate  of  rotation  of  the  exposure  apparatus. 
The  situation  becomes  still  more  complicated  when  this  rate 
is  changed.  If  it  were  changed,  as  it  must  be  to  preserve  the 
sensitivity  of  the  method  in  passing  from  high  to  low  illu- 
mination, the  whole  scale  of  magnitude  of  the  underexposure 
would  change,  and  a  shift  in  the  relative  evaluation  of  the 
luminosities  of  the  different  colors  might  very  well  be  ex- 
pected from  the  shape  of  the  sensation  curves  as  they  rise  to 
their  maximum.  In  fact  this  shift  is  found  in  the  work  of 
previous  investigators1  who  have  made  the  comparison  at 

Empfindungen  im  Gebiete  der  Sehnerven,'  Sitzungsber.  der  Wiener  Akademie,  Math.- 
Natur.  Klasse,  1878,  77,  Abth.  3,  p.  63.)  As  we  have  already  stated,  however  (p.  113), 
we  do  not  mean  to  draw  too  close  an  analogy  here  between  the  effect  on  the  bright- 
ness of  sensation  produced  by  keeping  the  intensity  of  light  constant  and  reducing 
the  time  of  exposure  of  the  eye  to  the  light,  and  the  effect  of  keeping  the  time  of 
exposure  of  the  eye  to  the  light  constant  and  reducing  the  intensity.  The  degree  to 
which  the  analogy  holds  can  scarcely  be  considered  as  fixed  until  more  work  is  done 
showing  the  way  in  which  the  luminosity  curves  for  the  different  colors  rise  to  their 
maximum  as  the  time  of  exposure  of  the  eye  to  the  different  colored  lights  is  increased. 

1  See,  for  example,  the  phenomenon  called  by  Ives  the  "reverse  Purkinje"  effect 
(Philos.  Mag.,  1912,  24,  Ser.  6,  pp.  170-173);  later  demonstrated  and  discussed  by 
Luckiesch  (Electrical  World,  March  22,  1913,  p.  620).  These  writers  have  found  that 
the  red  end  of  the  spectrum  shows  a  relatively  higher  luminosity  value  as  compared 
with  the  green  end  by  the  method  of  flicker  at  low  than  at  high  illuminations.  From 
the  shape  of  Broca  and  Sulzer's  curves  for  the  rise  of  visual  sensation,  to  its  maximum, 
for  example,  this  result  might  very  well  be  due  to  the  difference  in  the  relative  lumin- 
osity value  of  the  colors  caused  by  the  difference  in  the  length  of  exposure  given  to  the 
eye  in  the  method  of  flicker  at  the  faster  rates  of  speed  required  for  the  higher  illumina- 
tions and  at  the  slower  rates  for  lower  illuminations.  That  is,  the  longer  exposures 
given  by  the  slower  speeds  of  rotation  allow  the  colors  to  attain  a  higher  intensity. 
For  example,  the  speeds  used  by  Ives  for  what  he  calls  10  Illumination  Units  range, 
for  the  different  colors  for  five  observers,  from  7  to  10  cycles  per  second,  and  for  250 
Illumination  Units  from  10  to  22  cycles  per  second. 

Broca  and  Sulzer's  curves  (Fig.  i)  are  appended  here  for  one  order  of  intensity 
of  stimulus  (Comptfs  Rendus,  1903,  137,  p.  978.  For  other  intensities  see  p.  945). 
The  curves  given  were  selected  because  they  alone  show  a  comparison  between  the 
results  for  colored  and  white  light.  It  will  be  seen  from  these  curves  that  for  exposures 
less  than  .07  sec.  (approximate  value),  blue  and  green  rise  to  a  higher  value  than  red; 
for  exposures  ranging  from  .07  to  .11  sec.,  blue  rises  to  a  higher  value  than  red,  and 
red  higher  than  green;  and  for  exposures  ranging  from  .11  sec.  to  about  .25  sec.,  red 
rises  to  a  higher  value  than  blue  or  green. 

There  is  also  a  very  strong  probability  that  the  relative  lag  in  sensation  for  the 
different  wave-lengths  is  not  the  same  for  lights  of  low  intensity  as  for  lights  of  higher 
intensities.  In  fact  the  results  that  have  been  obtained  so  far  in  this  laboratory  in 
determining  the  development  time  of  the  sensations  aroused  by  red,  yellow,  green,  and 


126  C.  E.  FERREE  AND  GERTRUDE  RAND 

intensities  low  enough  to  necessitate  a  decided  reduction  in 
speed  of  rotation.  And  that  the  shift  is  different  from  the 
normal  effect  on  the  brightness  of  the  colors  produced  by  a 
decrease  of  illumination,  is  shown  by  the  fact  that  according 
to  the  results  of  these  investigators  it  is  in  a  different  direction 
from  that  given  by  the  equality  of  brightness  method. 
Moreover,  in  the  later  paper  it  will  be  shown  that  a  change  in 
this  evaluation  amounting  to  several  times  the  smallest  dif- 
ference in  luminosity  that  can  be  detected  by  the  method,  is 
also  produced  by  working  the  reverse  variation,  that  is,  by 
keeping  the  rate  of  rotation  constant  and  changing  the  ratio 
of  value  of  colored  to  colorless  sector.  It  is  difficult,  there- 
fore, to  avoid  the  conclusion  that  the  type  of  exposure  used  in 
the  method  of  flicker  is  an  important  factor  in  the  cause  of  its 
disagreement  with  the  results  obtained  by  other  methods. 

blue  lights  of  spectrum  purity  show  that  at  low  intensities  red  and  yellow  rise  more 
rapidly  in  photometric  value  than  green  and  blue.  This  result  is  quite  marked  in  those 
parts  of  the  curves  representing  an  exposure  time  of  the  same  order  of  magnitude  as 
is  used  in  the  method  of  flicker.  In  order  to  show  this  point  we  have  appended  here 


too. 


50. 


FIG.  i 


three  curves  representing  the  relative  rates  of  development  of  red,  yellow,  green,  and 
blue  at  intensities  which  we  will  designate  for  the  present  as  low  and  intermediate;  and 
of  red,  yellow,  and  green  for  a  higher  intensity.  These  determinations  were  made  by 


FLICKER  PHOTOMETRY 


127 


Reexamining  the  case,  then,  with  regard  to  the  underex- 
posure of  the  eye  by  the  method  of  flicker,  we  find  that  the 
short  exposure  times  necessary  to  the  method  cause  a  re- 

M.  A.  Bills  of  this  laboratory.  Later,  results  will  be  given  for  red,  green,  blue,  and 
yellow  at  a  number  of  intensities,  and  specifications  will  be  made  of  the  intensities 
employed  in  both  photometric  and  radiometric  units.  The  colored  lights  used  in 
determining  the  curves  given  below  were  obtained  from  a  spectrum  of  good  definition 
and  were  in  each  case  equal  in  photometric  value,  as  they  should  be  if  results  are  to  be 
used  in  interpreting  the  action  of  light  on  the  eye  under  the  conditions  imposed  by  the 


\ 


0-05- 


0.1 


FIG.  2 


method  of  flicker  when  the  photometric  balance  is  attained.  In  constructing  these 
curves  time  of  exposure  is  plotted  along  the  abscissa  and  brightness  of  color  along  the 
ordinate.  The  curves  in  Fig.  2  are  for  the  low  intensity;  in  Fig.  3  for  the  intermediate 
intensity;  and  in  Fig.  4  for  the  higher  intensity. 

It  is  very  probable  that  there  is  considerable  individual  difference  in  the  amount 
and  distribution  of  lag.  A  rigid  test  of  the  correspondence  of  difference  in  lag  to  the 
direction  of  deviation  of  results  gotten  by  the  method  of  flicker  from  those  obtained  by 
the  equality  of  brightness  method  would  require  that  the  photometric  determinations 
and  the  determination  of  lag  should  be  made  for  a  given  quality  and  intensity  of  light 
by  the  same  observer. 

If  it  should  be  found  that  there  is  an  individual  difference  in  the  amount  and  dis- 
tribution of  lag,  the  result  would  supplement  very  nicely  the  explanation  why  a  much 
higher  degree  of  reproducibility  is  gotten  by  the  method  of  flicker  than  by  the  method 


128  C.  E.  FERREE  AND  GERTRUDE  RAND 

duction  in  the  action  of  the  standard  and  comparison  lights 
on  the  eye.  If  this  reduction  were  equal  in  amount,  quite 
enough  difficulty  would  be  encountered.  But  it  is  not 

of  equality  of  brightness  only  when  the  results  of  a  single  observer  are  considered  (see 
footnote,  p.  115).  That  is  since  the  factor  of  color  difference  which  so  disturbs  the 
judgment  in  the  equality  of  brightness  method  is  eliminated  in  the  method  of  flicker, 
we  should  get  correspondingly  a  higher  degree  of  reproducibility  for  a  single  observer 
and  for  different  observers,  were  there  not  some  factor  present  in  the  method  of  flicker 
and  not  in  the  equality  of  brightness  method,  which  varies  from  individual  to  individual. 
So  supplemented  the  explanation  would  be  as  follows.  In  the  method  of  flicker  the 


6.oy  0-<  o-if  o.  a  0.25- 

FIG.  3 

judgment  for  a  single  observer  shows  a  higher  degree  of  reproducibility  than  in  the 
equality  of  brightness  method  because  of  the  elimination  of  the  disturbing  factor  o 
color  difference;  but  a  false  balance  is  established  by  the  method,  the  deviation  from 
the  true  balance  depending  in  direction  and  amount  for  different  observers  upon  the 
difference  in  the  amount  and  distribution  of  lag  in  the  rise  of  the  sensations  towards  the 
maximum.  The  difference  in  the  amount  and  direction  of  this  deviation  from  the  true 
balance  from  observer  to  observer  is  the  cause  of  the  relatively  low  degree  of  reproduci- 
bility of  results  when  the  work  of  different  observers  is  compared. 


f  /  I 

.•  •'  / 


fit 


/!: 


f         i     ' 
C    '         /    ( 


\   // 

lit 

944 

I     ,    < 

.     !    f 

•II 


A   /     ( 

tl? 
Ill 


i 

f  !' 


X    v 


FIG.  4 


a  0,0 


130  C.  E.  FERREE  AND  GERTRUDE  RAND 

equal  in  amount,  and  we  have  no  adequate  information  as  to 
the  amount  of  the  inequality.  Until  we  have  more  informa- 
tion with  regard  to  the  amount  of  the  reduction  and  the 
effect  it  produces,  any  successful  attempt  to  regulate  the 
relative  duration  of  the  exposure  to  colored  and  colorless  light, 
even  for  a  single  color  at  a  single  intensity,  can  scarcely  be 
more  than  the  result  of  chance.  Surely  to  expect  to  accom- 
plish this  for  all  intensities  of  all  colors  by  a  single  ratio  of 
exposure,  more  especially  by  means  of  a  I  :i  ratio,  as  has  been 
the  practice  in  the  past,  is,  it  would  seem  to  the  writers,  to 
ignore  the  sensation  principles  which  underlie  the  method. 
Obviously  this  ratio  requires  calibration,  and  to  give  the 
method  the  sureness  of  principle  required,  it  would  seem  that 
the  calibration  might  have  to  be  made  for  each  color  at  the 
particular  intensity  at  which  the  work  is  to  be  done.  This 
calibration  might  possibly  be  accomplished  by  means  of  an 
accurate  knowledge,  if  that  knowledge  could  be  secured  in 
sufficient  detail,  of  the  temporal  course  of  visual  sensation  as 
it  rises  to  its  maximum  for  the  given  intensity  of  light  used;  or 
it  might  be  done  by  comparing  the  results  obtained  by  the 
method  of  flicker  with  the  results  obtained  by  some  other 
method  adopted  as  a  standard.  So  far  the  tendency  seems 
to  have  been  to  look  for  this  standard  within  the  subject  of 
photometry  itself.  As  has  already  been  stated,  several 
writers  have  signified  a  desire  to  make  the  equality  of  bright- 
ness method  a  standard,  and  comparisons  have  been  made  of 
the  results  obtained  by  the  method  of  flicker  and  the  equality 
of  brightness  method. 

A  consideration  of  the  results  of  these  comparisons  together 
with  the  data  collected  by  one  of  the  writers  in  ten  years  use  of 
the  flicker  and  equality  of  brightness  methods  in  making  the 
brightness  matches  needed  for  the  work  in  color  sensitivity,  has 
influenced  us  to  open  the  question  anew  in  the  interests  of 
the  work  on  color  sensitivity.  In  the  work  with  these  two 
methods  all  done  at  comparatively  high  illuminations  and 
with  a  large  number  of  observers,  agreement  has  been  rare. 
For  this  reason  the  chief  incentive  to  make  the  present  study 
has  not  been  to  establish  disagreement,  but  to  investigate 


FLICKER  PHOTOMETRY  I31 

further  the  causes  of  disagreement.  The  results  of  this  study 
seem  to  indicate  that  the  type  of  exposure  of  the  eye  to  its 
stimulus  by  the  method  of  flicker  is  an  important  cause  of 
disagreement. 

So  much  for  the  theoretical  considerations  relating  to  the 
method  of  flicker.  To  test  the  accuracy  of  some  of  the  more 
important  points  that  have  come  up,  a  plan  of  experimentation 
has  been  formulated  and  in  part  carried  out.  So  far  as  the 
results  of  that  experimentation  will  be  reported  upon  in  this 
paper,  the  following  things  will  be  shown,  (i)  By  comparing 
the  time  required  for  the  sensations  aroused  by  colored  and 
colorless  light  to  reach  their  maximum  of  intensity,  we  have 
already  shown  that  as  a  general  case  the  eye  is  very  much 
underexposed  to  its  stimulus  by  the  method  of  flicker,  and 
we  have  concluded  that  the  effect  of  this  underexposure 
on  the  brightness  component  of  sensation  will  be  unequal 
in  amount  for  colored  and  colorless  light,  and  should  lead, 
therefore,  to  a  false  estimation  of  the  brightness  of  the 
colors.  That  this  conclusion  is  justified  so  far  as  our  work  is 
concerned,  will  be  demonstrated  in  part  by  comparing  the 
results  of  the  method  of  flicker  with  those  obtained  by  the 
equality  of  brightness  method,  in  which  case  the  eye  is  fully 
exposed  to  its  stimulus,  and  showing  that  for  the  method  of 
flicker  there  is  for  our  observers  for  the  intensities  of  light 
used  and  for  the  rate  of  rotation  of  the  photometer  head 
required  for  these  intensities,  a  characteristic  underestimation 
of  the  brightness  of  red  and  yellow  and  overestimation  of  the 
brightness  of  blue  and  green.  That  this  characteristic  devia- 
tion is  due  to  the  type  of  exposure  used  in  the  method  of 
flicker  and  not  to  some  other  factor  will  be  further  shown  in 
the  consideration  of  our  second  point.  (2)  We  have  said 
that  the  ratio  of  the  time  of  exposure  should  be  considered 
as  a  factor  influencing  the  results  obtained  by  the  method  of 
flicker.  In  order  to  confirm  this  judgment  of  the  case,  we 
have  varied  this  ratio,  keeping  the  other  conditions  constant, 
and  have  found  that  a  corresponding  variation  is  produced 
in  the  results.  That  is,  by  changing  the  value  of  the  colored 
and  colorless  sectors  in  the  rotating  disc  we  have  used  to 


132  C.  E.  FERREE  AND  GERTRUDE  RAND 

regulate  the  time  of  exposure  in  the  method  of  flicker,  corre- 
sponding variations  are  obtained  in  the  characteristic  under- 
estimations  of  red  and  yellow  and  the  overestimations  of  blue 
and  green.  These  variations,  it  will  be  shown,  moreover,, 
are  very  much,  greater  than  the  changes  in  luminosity  that 
are  required  to  be  detected  by  the  method  of  flicker,  and  arey 
therefore,  worthy  of  being  taken  into  account  in  an  evaluation 
of  the  usefulness  of  the  method,  whatever  method  be  adopted 
as  a  standard  for  comparison.  And  (3)  we  have  contended 
that  if  the  equality  of  brightness  method  be  adopted  as  the 
standard  for  work  in  color  photometry,  the  method  of  flicker 
does  not  satisfy  the  requirements,  for  it  does  not  give  results 
which  agree  in  the  average  with  those  obtained  by  the  equal- 
ity of  brightness  method.  This  will  be  shown  both  from 
results  of  our  own  work  and  from  a  preponderance  of  the 
work  done  by  others  who  have  made  the  comparison.  In 
our  own  work  the  comparison  has  been  made  for  a  series 
of  intensities  which  may  be  considered  as  at  least  fairly  repre- 
sentative of  the  higher  intensities,  they  being  considered  more 
favorable  to  agreement  by  Dr.  Ives.1  Especial  care  has  been 
taken  in  this  series  to  duplicate  at  one  point  the  intensity 
which  Dr.  Ives  finds  the  most  favorable  to  agreement. 

The  remainder  of  the  paper  will  be  taken  up  with  the 
demonstration  of  these  three  points. 

I.  THE  UNDERESTIMATION  OF  THE  LUMINOSITIES  OF  REI> 

AND  YELLOW  AND  THE  OVERESTIMATION   OF  THE 
LUMINOSITIES  OF  BLUE  AND  GREEN 

Special   tables   have   not   been   prepared   for   this   point 
because  the  results  can  readily  be  seen  in  the  tables  for  points 

II.  and  III.     In  these  tables  taken  collectively  the  comparison 
will  be  shown  for  a  representative  series  of  variations,  both 
of  the  ratio  of  the  time  of  exposure  to  colored  and  colorless 
light  and  of  the  intensity  of  the  lights  employed.     In  every 
case  underestimation  is  found  to  be  characteristic  for  red  and 
yellow,  and  overestimation  for  blue  and  green. 

1  Ives,  H.  E.,  'Studies  in  the  Photometry  of  Lights  of  Different  Colors,  Philos^ 
Mag,,  1912,  24,  Ser.  6,  pp.  149-188. 


FLICKER  PHOTOMETRY  *33 

II.     THE  VARIATION  OF  THE  RATIO  OF  THE  TIME  OF  EXPOSURE 

TO   THE    COLORED   AND    COLORLESS    LIGHT   CAUSES   A 

CORRESPONDING  VARIATION  IN  THE  CHARACTERISTIC 

UNDERESTIMATION  OF  RED  AND  YELLOW  AND 

OVERESTIMATION    OF    BLUE   AND    GREEN 

As  has  already  been  stated,  the  work  under  this  heading 
has  been  undertaken  in  part  to  show  the  preceding  point, 
and  in  part  to  show  that  the  amount  of  this  underestimation 
and  overestimation  is  a  variable  function  of  the  ratio  of  the 
time  of  exposure  to  the  colored  and  the  colorless  light.  The 
effect  of  the  variation  was  determined  both  when  the  com- 
parison was  made  between  colored  and  colorless  pigment 
surfaces,  and  between  colored  and  colorless  lights.  For  the 
pigment  surfaces  the  standard  red,  green,  blue,  yellow,  white, 
and  black  of  the  Hering  series  of  papers  were  used.  For  the 
colored  lights,  two  sources  have  been  used:  the  Wratton  and 
Wainwright  color  filters,  and  the  light  of  the  spectrum. 
Since  the  work  with  the  spectrum  as  source  has  not  yet  been 
finished,  results  will  be  given  at  this  point  from  the  work  with 
the  filters.  Of  these  filters,  only  the  Alpha  and  Eta  were 
used.  The  former  transmits  a  band  of  red  from  the  end  of 
the  spectrum  to  .65  ju,  the  latter,  a  band  in  the  blue-green 
from  .52  n  to  .465  /z.  These  two  alone  were  used  for  the 
following  reasons:  (i)  They  are  fairly  representative  of  the 
colors  that  show  a  relative  change  in  luminosity  with  change 
of  intensity.  And  (2)  the  yellow,  green,  and  blue  filters  each 
transmits  components  that  undergo  opposite  luminosity 
changes  with  a  change  of  intensity  of  the  source.  That  is, 
the  best  yellow  of  the  series  transmits  also  a  green  com- 
ponent; the  best  green,  a  yellow  component;  and  the  best 
blue  transmits  some  of  the  violet. 

The  photometric  apparatus  employed  was  for  the  sake  of 
comparison  made  to  conform  very  closely  in  its  essential 
features  to  that  described  by  Dr.  Ives.1  The  general  plan 
of  our  apparatus  is  indicated  in  Fig.  5.  It  consists  of  a  photo- 
meter bar  carrying  the  standard  white  light  (A),  a  second  bar 
carrying  the  colored  light  (£),  a  sectored  disc  (C),  and  a 

1  Ives,  H.  E.,  op.  cit.j  p.  161. 


134  C.  E.  FERREE  AND  GERTRUDE  RAND 

screen  (D)  provided  with  a  small  aperture  (0)  through  which 
the  light  comes  to  the  eye.  The  standard  white  light  was 
enclosed  in  a  black  light-proof  box  (E),  which  was  provided 


FIG.  5 

in  front  with  a  circular  opening  4  cm.  in  diameter  for  the  trans- 
mission of  the  light.  In  passing  to  the  sectored  disc,  the 
light  was  screened  both  from  the  observer's  eye  and  from  the 
colored  source  by  black  screens  properly  placed.  The  light 
which  was  passed  through  the  colored  filters  was  placed  in  a 
similar  light-proof  box  (F)  provided  with  an  opening  4  cm. 
square  for  the  transmission  of  the  light.  Above  and  below 
this  opening  were  grooves  into  which  the  color  filters  were 
slid.  The  sectored  discs  were  made  of  aluminum.  The  edges 
of  these  discs  were  carefully  bevelled  and  the  surface  was  kept 
freshly  covered  with  magnesium  oxide  deposited  from  the 
burning  metal.  The  aperture  in  the  screen  through  which 
the  light  passed  to  the  observer's  eye  was  3  mm.  square. 
The  visual  angle  subtended  by  this  aperture  at  the  observer's 
eye  at  20  cm.  distance  was  very  small.  A  small  angle  was 
needed  to  guard  against  the  unequal  sensitivity  of  the  central 
and  paracentral  portions  of  the  retina  to  flicker,  and  against 
the  difference  in  their  brightness  sensitivity  to  colored  ancj 
colorless  light.  A  13-candle-power  Mazda  lamp  was  used  as 
source  for  the  colorless  light,  and  13-cp.,  52-cp.,  and  i3O-cp. 
lamps  for  the  colored  light.  These  lamps  were  operated  on  a 
no  D.C.  circuit  in  series  with  an  ammeter  and  finely  gradu- 
ated rheostat  to  guard  against  fluctuations  in  the  current  and 


FLICKER  PHOTOMETRY  ^35 

loss  of  efficiency  in  the  lamps.  Also  fresh  lamps  were  sub- 
stituted at  the  beginning  of  each  series  of  observations.  As 
a  check  on  the  results  obtained  from  these  lamps,  several 
series  of  observations  were  made  using  a  standardized  tungsten 
lamp,  street  series,  i6.6-cp.  operated  at  11.43  volts  by  a 
storage  battery  for  the  colorless  light,  and  a  similar  lamp  of  67- 
cp.  operated  by  a  storage  battery  at  10.35  volts  for  the 
source  of  the  colored  light. 

The  method  of  making  the  flicker  judgment  was  as  follows: 
A  preliminary  determination  was  made  of  the  approximate 
setting  of  the  light  which  was  being  moved,  to  give  equaliza- 
tion. The  speed  of  rotation  of  the  sectored  disc  was  then 
reduced  until  flicker  was  obtained.  The  position  of  the  light 
was  again  adjusted  until  no  flicker  was  obtained,  and  so  on. 
This  variation  in  the  speed  of  rotation  of  the  disc  and  the 
position  of  the  light  was  continued  until  the  position  was 
ascertained  that  gave  no  flicker  for  the  lowest  speed  of  rota- 
tion. The  final  determination  of  this  point  was  made  by 
moving  the  light  in  both  directions  until  noticeable  flicker  was 
obtained,  and  taking  the  average  of  these  two  readings. 
The  movement  required  to  give  flicker  on  either  side  of  this 
average  position  ranged  usually  from  2  to  9  mm.  depending  to 
some  extent  upon  the  observer  and  the  intensity  of  illumina- 
tion used.  Employing  the  above  apparatus  and  method, 
results  were  obtained  for  the  highest  intensity  of  colored  light 
used  for  a  total  open  sector  of  315°,  270°,  225°,  180°,  and  45°; 
and  for  the  other  intensities,  for  a  total  open  sector  of  315°, 
180°,  and  45°.  In  making  the  comparisons  by  the  equality 
of  brightness  method,  the  disc  was  rotated  until  one  of  its 
edges  bisected  horizontally  the  photometric  field.  The 
results  are  shown  in  Tables  II.-V.  They  will  be  sum- 
marized briefly  as  follows:  (i)  For  all  values  of  open  sector 
and  for  all  intensities  of  light,  there  was  an  underestimation 
of  the  luminosity  of  the  red  light  and  an  overestimation  of  the 
luminosity  of  the  blue-green.  (2)  As  the  size  of  the  open 
sector  was  decreased,  there  was  a  corresponding  increase  in 
the  amount  of  the  underestimation  of  the  luminosity  of  the 
red  for  all  the  intensities  employed,  and  of  the  overestimation 


136 


C.  E.  FERREE  AND  GERTRUDE  RAND 


5 


'.9 


111 

to  1 

111 
S  «^ 

dies 
1!* 


- 


m 


lit 
3ii 


•  2  IS 

Is 


CO 


Hjfi 

co  ^  ^  4*"O  vo  co  vo  vr>  ^^  vovo  K-  ON  ^06  vo  t>.oo  t 

^ 

fe  ii 

U 
vo  vo  vo  vo       vo            vo       vo 

vo 

F^  $ 

1*    III 

| 

§  5        1§J 

VO                                                                                                                                                 VO 

•<U        «« 

co             n-             co             -*             co                       co 

ill 
FI 

Us 

GIT 

s 
t      t            ^                 ^? 

T   +    r   +    r      + 

>i*O   s 

fitls 

§ 

VO 

1  i^-iJ  J  MC^ 

O              O              "-i              co             ON                        t*» 

QWM|g| 

1              +               1               +               1                          + 

III 

CJ 
10  vo  vo  vo         vo                 10 

VO 

•5          QJ>3 

co  vo  t^.  co  O  00   c4   -4"O   -4-  O  06   M   •**•  "4-  vovd  VO  t^vo" 
CO  CO  COOO  OO   t^  O    O    O    ON  ONOO  OOOOOOOOOO   tv.t-».l^J 

LO  CO 

r^  t^. 

^ 

J3                 iu 

O  c/3 

ooooooooooooooooooooc 
toO  vovoO  vovoO  voioO  vovoO  voO  vovoO  vo 

83 

IB-S  «^ll 

CJ 

M1  Hi 

0° 

vo                             ^                             co 
vo             HH              to             ^o             to                       r< 
c^              ON             ON             O              ^*                       OO 

3 

(    g                                g                                           g 

.                           O      2i                                                 <U      LH                                                                      <U      t- 

^        3  «    ^        ^feo'S               ^^ 
M         M         M         pQ         M                  PQ 

gl 

§||      il|      s|| 

Ii 

V04->g                               VO^jg                              OO-ug 

o  ^ 

co'XJ    CU  co               c»  -3    &.  co               co^    Q*  co 

l-l                                                 UO                                                M 

111 

d 
o 

co 

FLICKER  PHOTOMETRY 


137 


^| 

•4 

to 

o  w  o 

HI  b»  N  vo  t^  O^ 

COON         NHI         OOrftO^f- 

4 

fl 

VO  00  00    10  t^VO 

^•***aa*^- 

J* 

II 

6 

gS 

to 

to                          10           toco 
oo  oo  ONVO  00  ONOO  oo  oo  ONOO  oo 

U  « 

^  a 

O   cfl 

ill 

to                                            to 

•! 

3&* 

N              to 

to             •*             to             •«*• 

6 

%z 

. 

£ 

>  2 

5 

| 

*J 

c*             ^ 

00                  t^                 to 

u 

|I 

•r}-                  10 

1      + 

oo            t~-          vo           oo 

1      +      1      + 

•o 

•^1 

^|8 

•Slo. 

§ 

3 

o 

||l 

2*°o% 

ll*J 

to 
to 

tO                      HI 

to               "«*•                                  CO 

$ 

* 

5«w 

1       + 

1      +      1      + 

1      ^ 

"o^o 

s  ^ 

B 

3      rt 

4;  .2?  c  £j 

1—1    rf 

o 

*      w 
> 

g  «.s~ 

to 

s  g 

oo 

MtO          NVOtOto                  lOtOlO 

H         % 

1 

p§3fe 

^ON'O  f^t^R 

M        & 
«       S 

s^oo^as^oo^^R 

H          0 

t; 

1* 

HI 

<        M 

HI     HI                                        HI    CS 

Q 

^ 

Ho 
w 

d             - 

b 

i 

!Q 

^o 

^  § 

< 

fo 

*o  /5 

10  O  to  to  O  to 

too  «oioO  to«oO  totoO  to 

•4 

«» 

t—  (  CO    "^  HI  OO    ~^t" 

HIOO      ThhHOO      TJ-HICQ      ^HIOO      Tj- 

|1 

C<1    l-l               tO   HI 

ill 
&§* 

Distance  of 
White  Light 
Giving  Equality 
of  Illumination 

10 

vo             to 

oo           oo 

i 

w 

oo            o^          oo           oo 

C! 

G                               & 

1 

T!        *%> 

•8     1*  3     J^ 

Cb           CQ           Cb           CD 

c 

1- 

«  l41'= 

gg.u             Ad.||.g 

55 

•"a    s  c 

hH  '^      0»                                  CO      rt            H-4     CD 

J?£  S  c            ""  g      S  c 

b 

d2  §  S            o  *g  °  "  |  w 

c 

1s 

^.TJ  &  2     OH  g 

^*.22^Cy                  rtONctf^o 
N  ^    CX  co               t^^J  OO  +->   CX  co 
to                           vo 

t 

1 

12 

I 
c 

II 

Jl     1 

8*                           VO  rt   & 

v: 

vo  to  -2 

to                    vc5  w  -2 

HI                                                 HI 

138  C.  E.  FERRER  AND  GERTRUDE  RAND 

of  the  blue-green.  (3)  The  amount  of  change  in  the  photo- 
metric value  of  the  color  produced  by  varying  the  ratio  of 
exposure  to  colored  and  colorless  light  was  many  times  the 
smallest  amount  of  change  that  can  be  detected  by  the  method 
of  flicker,  and,  therefore,  must  be  considered  of  consequence 
in  relation  to  the  application  of  the  method  to  practical  work. 

Column  I  of  these  tables  represents  the  source  of  white 
light;  Column  2,  the  source  of  colored  light;  Column  3,  the 
color  used;  Column  4,  the  distance  of  the  white  light  from  the 
disc  when  judgment  of  equality  is  given  by  equality  of  bright- 
ness method;  Column  5,  the  value  of  the  colored  sector  for 
the  method  of  flicker;  Column  6,  the  distance  from  the  disc 
at  which  the  white  light  has  to  be  placed  to  give  the  judgment 
of  no  flicker;  Column  7,  the  difference  in  the  distance  the 
white  light  was  placed  for  the  equality  of  brightness  method 
and  the  flicker  method  with  180°  of  colored  sector;  Column  8, 
the  change  in  the  distance  of  the  white  light  produced  by 
varying  the  value  of  the  colored  sectors  in  the  method  of 
flicker;  Column  9,  the  distance  the  white  light  has  to  be  moved 
in  the  equality  of  brightness  method  to  change  the  judgment 
from  equality  to  just  noticeably  lighter  or  darker;  Column  10, 
the  distance  the  white  light  has  to  be  moved  in  the  flicker 
method  to  change  the  judgment  from  no  flicker  to  just 
noticeable  flicker;  and  Column  II,  the  number  of  revolutions 
per  second  of  the  sectored  disc  for  the  method  of  flicker. 

Tables  IV.  and  V.  represent  the  results  of  Tables  II.  and 
III.  expressed  in  percentage  of  luminosity  at  the  photometric 
screen. 

Pigment  papers  are  still  used  in  a  great  many  laboratories 
for  the  investigation  of  color  sensitivity,  and  because  of  their 
convenience  and  ease  of  manipulation,  they  probably  will  be 
used  for  many  years  to  come  for  preliminary  work  and  for  a 
certain  class  of  investigations  in  which  only  comparative 
results  are  wanted.  In  estimating  the  brightness  or  luminos- 
ity of  these  pigment  colors,  the  method  of  flicker  is  now 
much  more  extensively  used  perhaps  than  any  of  the  other 
methods  of  making  brightness  comparisons.  For  this  reason 
we  have  considered  it  worth  while  to  extend  our  work  to  the 


FLICKER  PHOTOMETRY 


139 


TABLE  IV 

OBSERVER  A 
Showing  the  Results  in  Table  II.    Expressed  in  Percentage  of  Luminosity 


Disagreement 
Between 
Equality  of 

Change 

Amount  of  Change  that 
Can  Be  Detected  by 

Source  of 
White  Light 

Source  of 
Colored  Light 

Color 

Brightness 
Method  and 
Flicker  Method 
with  180° 
Open  Sector 

Produced  by 
Varying 
Sectors 

Equality  of 
Brightness 
Method 

Flicker 
Method 

13  cp. 

13    cp.    151    cm. 

Red 

-is  % 

-  4-8% 

5     % 

4% 

distant        from 

Blue- 

photometric 

green 

+12.3 

+  6.3 

3-7 

.6 

screen 

52    cp.    151    cm. 

Red 

—20 

-  7-5 

7 

4 

distant        from 

Blue- 

photometric 

green 

+30 

+  13 

7-3 

.6 

screen 

130   cp.    89   cm. 

Red 

—  21 

-  9 

7 

•9 

distant        from 

Blue- 

photometric 

green 

+  197 

+  7-3 

6.8 

•7 

screen 

16.6  cp. 

67   cp.   standard 

Red 

-23.6 

-  8-3 

8.7 

i 

standard 

lamp,     89    cm. 

Blue- 

lamp 

distant        from 

green 

+33 

+  8.3 

8.5 

.8 

photometric 

screen 

TABLE  V 

OBSERVER  B 


13  cp. 

52   cp.    151    cm. 

Red 

-30% 

-16% 

7-5% 

1-7% 

distant        from 

Blue- 

photometric 

green 

+  17- 

+  18 

7-7 

1.2 

screen 

16.6  cp. 

67   cp.   standard 

Red 

-28. 

—  12.4 

6.5 

1.6 

standard 

lamp,     89     cm. 

Blue- 

lamp 

distant        from 

green 

+31-7 

+24. 

9 

2 

photometric 

screen 

investigation  of  the  effect  of  varying  the  value  of  the  colored 
and  the  colorless  sectors  on  the  brightness  of  the  pigment  colors 
as  determined  by  the  method  of  flicker.  Of  the  devices 
available  for  applying  the  method  to  these  colors,  the  Schenck 
apparatus  was  selected  as  best  suited  to  our  purpose.  As 
colors  to  be  investigated,  the  red,  green,  blue,  and  yellow  of 
the  Hering  series  of  standard  papers  were  chosen.  Sectors 
of  the  value  of  180°,  270°,  and  300°  were  used.  Values  lower 


140  C.  E.  FERREE  AND  GERTRUDE  RAND 

than  1 80°  were  not  used  because  they  could  not  be  accurately 
obtained  with  the  type  of  photometer  employed.  Two  in- 
tensities of  illumination  were  used,  one  of  390  foot-candles 
(vertical  component)  received  directly  under  a  skylight  and 
diffusion  sash  of  ground  glass;  the  other,  5  foot-candles,  the 
illumination  of  a  room  lighted  by  windows.  Space  will  be 
given  here  only  for  the  results  for  the  higher  illumination. 
This  illumination  was  carefully  chosen  far  above  the  range  of 
intensities  at  which  the  Purkinje  phenomemon  occurs  when 
the  eye  is  fully  exposed  to  its  stimulus,  in  order  to  subject 
our  demonstration  to  a  rigid  test.  We  were  seeking,  for 
example,  to  ascertain  whether  an  intensity  might  not  be 
found  so  high  that  the  underexposure  of  the  eye  to  its  stimulus 
by  the  method  of  flicker  would  not  cause  an  underestimation 
of  the  brightness  of  red  and  yellow  and  an  overestimation  of 
the  brightness  of  blue  and  green.1  That  these  underestima- 
tions  and  overestimations  occur  at  this  high  illumination  and 
by  amounts  many  times  the  smallest  brightness  difference  that 
can  be  detected  by  the  method,  will  be  shown  in  Table  VI. 

Column  I  of  this  table  shows  the  color  used;  Column  2,  the 
black-white  value  of  the  color  estimated  by  the  equality  of 
brightness  method;  Column  3  gives  the  value  of  the  colored 
sector;  Column  4,  the  white-black  value  of  the  color  estimated 
by  the  flicker  method;  Column  5  gives  the  difference  in  the 
result  by  the  equality  of  brightness  and  flicker  method  with 
1 80°  colored  sector;  Column  6  gives  the  change  produced  in 
the  result  by  the  method  of  flicker  by  varying  the  size  of  the 
colored  sector;  Column  7  gives  the  amount  of  change  that 
can  be  detected  by  the  equality  of  brightness  method;  and 
Column  8,  by  the  flicker  method. 

III.     THE  METHOD  OF  FLICKER  DOES  NOT  GIVE  RESULTS 
WHICH  AGREE  IN  THE  AVERAGE  WITH  THOSE  OBTAINED 
BY  THE  EQUALITY  OF  BRIGHTNESS  METHOD 

Nothing  will  be  added  in  this  section  except  to  make  our 
comparisons  at  the  intensity  of  illumination  found  to  be  most 

1  We  have  been  careful  to  choose  high  intensities  because  Dr.  Ives  has  contended 
that  at  high  intensities  the  disagreement  between  the  methods  of  flicker  and  equality 
of  brightness  tends  to  disappear. 


FUCKER  PHOTOMETRY 


141 


TABLE  VI 

OBSERVER  A 

Showing  that  the  Underestimation  of  Red  and  Yellow  and  the  Over  estimation  of  Blue  and 
Green  is  a  Characteristic  of  the  Method  of  Flicker  for  Light  of  the  Intensity  Used 
in  this  Work,  and  that  the  Amount  of  this  Underestimation  and  Over- 
estimation  is  a  Variable  Function  of  the  Ratio  of  the  Time  of 
Exposure  of  the  Eye  to  the  Colored  and  the  Colorless 
Light. 


Color 

Equality  of 
Brightness 
Method 

Flicker  Method 

Difference  by 
Equality  of 
Brightness 
Method  and  by 
Flicker  Method 
with  1  80° 
Colored  Sector 

Change  Pro- 
duced by 
Varying 
Sectors 

Change  that 
can  be  Detected 
by 

White-black 
Value 

Value  of 
Colored 
Sector 

White-black 
Value 

Equal- 
ity of 
Bright- 
ness 

Flicker 
Method 

Method 

Red 

White    64° 

300° 

White    58.9° 

-174° 

-I2.3° 

8° 

1.8° 

_-* 

Black  296° 

Black  301.1° 

270° 

White    56.2° 

1.2° 

• 

Black  303.8° 

180° 

White    46.6° 

1.8° 

Black  313.4° 

Yellow 

White  332° 

300° 

White  328.3° 

-18.6° 

-14.9° 

9-5° 

2° 

Black    28° 

Black    31.7° 

270° 

White  321.7° 

1.8° 

Black    38.3° 

1  80° 

White  313.4° 
Black    46.6° 

1.8° 

Green 

White    88.5° 

300° 

White    99° 

+26.4° 

+  15-9° 

9° 

45° 

Black  251.5° 

Black  261° 

270° 

White  105.5° 

•9° 

Black  254.5° 

180° 

White  114.9° 

45° 

Black  245.1° 

Blue 

White    12.5° 

300° 

White    14.5° 

+  10.7° 

+  8-7° 

5-3° 

2.2° 

Black  347.5° 

Black  345.5° 

270° 

White    19.1° 

14° 

Black  340.9° 

1  80° 

White    23.2° 

•9° 

Black  336.8° 

favorable  for  agreement  by  Dr.  Ives.1  The  plan  of  the  ap- 
paratus used  in  this  work  is  indicated  in  Fig.  6.  A  spectro- 
scope was  used  to  give  the  colored  light;  a  32-cp.  carbon 
lamp  (,F)  was  used  as  the  source  of  the  colorless  light.  This 
lamp  gave  a  light  of  the  same  quality  as  that  used  by  Dr.  Ives, 
namely,  the  quality  of  the  carbon  standard  of  4.85  watts  per 
mean  spherical  candle.  When  placed  at  32.6  cm.  from  the 
sectored  disc  (£)),  270  meter  candles  of  light  were  reflected 
1  Ives,  H.  E.,  op.  cit.,  p.  173. 


142  C.  E.  FERRER  AND  GERTRUDE  RAND 

from  the  disc.  The  eye  piece  was  removed  from  the  spectro- 
scope and  a  lens  system  was  used  in  its  place  consisting  of  two 
lenses  (A)  and  (5),  one  to  render  the  light  emerging  from  the 
objective  slit  (C)  parallel,  and  the  other  to  focus  it  on  the  eye 
30  cm.  distant.  Between  the  eye  and  the  focusing  lens  (E) 
was  interposed  the  sectored  disc  (D).  Thus  the  light  reflected 
from  the  sectored  disc  suffered  no  absorption  in  passing  to  the 
eye.  A  stimulus-opening  (E)  16  mm.  in  diameter  was  placed 
in  front  of  the  disc  20  cm.  from  the  eye.  This  subtended  the 


FIG.  6 

same  visual  angle  as  the  field  size  that  Dr.  Ives  found  to  be 
the  most  favorable.  A  pupillary  aperture  I  mm.  square 
placed  in  front  of  the  eye  reduced  the  light  reflected  from  the 
white  disc  to  the  intensity  called  by  Dr.  Ives  270  illumination 
units.1  The  colors  used  were  a  very  narrow  band  of  the 
spectrum  in  the  region  of  .68  /*,  .57  /*,  .52  /*,  and  .47  /*,  giving 
the  four  pure  colors  red,  yellow,  green,  and  blue.  The  method 
of  making  the  comparison  was  as  follows:  The  sectored 
disc  was  turned  so  that  its  edge  bisected  horizontally  the 
photometric  field,  and  the  luminosity  of  the  colored  field  was 
altered  by  changing  the  width  of  the  collimator-slit  until  it 
equalled  by  the  equality  of  brightness  method  the  270  illumi- 
nation units.  Using  this  slit  width,  then,  the  disc  was  rotated 
and  the  position  of  the  white  light  was  adjusted  until  no 

1  By  using  a  pupillary  aperture  I  mm.  square,  Dr.  Ives  has  reduced  the  light 
entering  the  eye  by  an  amount  which,  so  far  as  we  can  see,  can  not  be  determined. 
He  has  established  an  arbitrary  unit  which  he  calls  an  illumination  unit.  We  can 
not,  therefore,  compare  the  intensities  of  light  used  by  us  in  the  preceding  experi- 
ments (pp.  134  ff.)  with  the  270  illumination  units  used  by  Dr.  Ives.  If  one  were  to 
judge,  however,  by  the  apparent  brightness  of  the  disc  in  the  two  cases,  he  would  have 
to  say  that  the  amount  of  light  entering  the  eye  was  considerably  greater  for  our 


FLICKER  PHOTOMETRY 


'43 


flicker  was  obtained.  The  flicker  determinations  were  made 
with  315°,  1 80°,  and  45°  total  open  sector  as  before.  The 
results  are  shown  in  Tables  VII  and  VIII. 


TABLE  VII 

OBSERVER  A 

Showing  that  the  Underestimation  of  Red  and  Yellow  and  the  Over  estimation  of  Blue  and 
Green  is  a  Characteristic  of  the  Method  of  Flicker  for  Lights  of  the  Intensity  Used 
in  this  Work,  and  that  the  Amount  of  this  Underestimation  and  Over- 
estimation  is  a  Variable  Function  of  the  Ratio  of  the  Time  of 
Exposure  of  the  Eye  to  the  Colored  and  the  Colorless 
Light.    Intensity  same  as  was  used  by 
Ives 


Wave- 
length 

Equality  of 
Brightness 
Method 

Flicker  Method 

Difference  by 
Equality  of 
Brightness 
Method  and 
by  Flicker 
Method 
with  1  80° 
Colored 
Sector 

Change 
Produced 
by  Varying 
Sectors 

Amount  of  Change 
that  Can  Be 
Detected  by 

No.  of 
Revolu- 
tions per 
Second, 
Flicker 
Method 

Distance  of 
White  Light 
Giving 
Equality  of 
Illumination 

Value  of 
Colored 
Sector 

Distance  of 
White  Light 
Giving  no 
Flicker 

Equality 
of  Bright- 
ness 
Method 

Flicker 
Method 

.68  /i 

32.6  cm. 

3IS° 

41.5  cm. 

—  1  1.6  cm. 

—3.6  cm. 

2.4  cm. 

•5    cm. 

9.2 

1  80° 

44.2 

•45 

12 

45° 

45-1 

•5 

II 

•57  /• 

32.6 

315° 

37-4 

-  6.9 

-3-4 

2.8 

•4 

9.8 

1  80° 

39-5 

•4 

H 

45° 

40.8 

•4 

12 

.52  M 

32.6 

315° 

23 

+  13-6 

+4-9 

2 

•5 

9-7 

1  80° 

19 

•4 

13 

45° 

18.1 

•4 

11.7 

•47  M 

32.6 

315° 

23 

+  I3-8 

+5 

2-3 

•45 

9-9 

1  80° 

18.8 

•4 

14.1 

45° 

18 

•45 

12 

higher  intensities  than  the  270  illumination  units  used  by  Dr.  Ives.  Thus  it  seems  prob- 
able that  most  of  our  preceding  tests  were  made  with  an  intensity  of  light  equal  to  or 
greater  than  that  used  by  him.  His  claim,  it  will  be  remembered,  was  that  one  of  the  two 
causes  of  disagreement  between  the  results  obtained  by  the  methods  of  flicker  and 
equality  of  brightness  in  preceding  experiments  is  the  low  intensity  of  the  lights  used. 
(The  other  was  the  lack  of  proper  regulation  of  the  size  of  the  photometric  field.) 
We  do  not  believe  that  either  one  of  these  factors  is  the  fundamental  cause  of  disagree- 
ment, as  is  attested  in  our  experiments  by  the  fact  that  strong  disagreement  remains 
when  both  of  them  have  been  eliminated,  at  least,  as  completely  as  they  were  eliminated 
by  Dr.  Ives.  A  consideration  of  the  functioning  of  the  eye  under  very  short  exposures 
to  light,  shows,  we  believe,  a  much  more  fundamental  cause  of  disagreement,  namely, 
the  difference  in  the  way  in  which  the  eye  responds  to  light  stimuli  when  presented 
for  the  lengths  of  time  used  in  the  two  methods. 


144 


C.  E.  FERREE  AND  GERTRUDE  RAND 
TABLE  VIII 

OBSERVER  B 


.68/1 

32.6 

3iS° 

4i-3 

-11.6 

-4 

3 

.8 

12 

1  80° 

44.2 

•7 

H 

45° 

45-3 

.8 

13-4 

•57  M 

32.6 

315° 
180° 

38 
41-5 

-  8.9 

-4-3 

2.9 

3 

12.5 
14.2 

45° 

42.3 

.8 

I3-I 

.52  M 

32.6 

315° 

234 

+  I2.I 

+3-9 

3-3 

.8 

12 

1  80° 

20.5 

•7 

H 

45° 

19-5 

-7 

12.2 

•47  /* 

32.6 

315° 

22.8 

+  12.6 

+4 

3-5 

•9 

II.  I 

1  80° 

2O 

•7 

144 

4.5° 

18.8 

.8 

12.8 

It  was  stated  in  the  beginning  of  the  paper  that  disagree- 
ment between  the  results  of  the  method  of  flicker  and  equality 
of  brightness  would  be  shown  from  a  preponderance  of  the 
work  done  by  others  who  have  made  the  comparison.  As  a 
general  case  the  fact  scarcely  needs  more  than  the  pointing 
out.  Before  the  work  of  Ives,  disagreement  was  pretty 
generally  admitted.  Bell1  says:  "That  the  flicker  and  equal- 
ity of  brightness  methods  do  not  give  coincident  results  when 
we  consider  the  general  case  of  flicker  photometers,  as  com- 
pared with  equality  of  brightness  photometers,  is  a  fact  that 
has  been  too  long  familiar  to  photometrists  to  admit  of  a  dis- 
cussion." Comparisons  of  the  two  methods  have  been  made 
by  Whitman,  Wilde,  Dow,  Bell,  Stuhr,  Luckiesh  and  Ives. 
Whitman2  compared  the  luminosities  of  a  red  and  green  light 
placed  6  ft.  apart  on  a  photometer  bar.  He  found  that  the 
setting  of  the  photometer  for  equality  of  illumination  differed 
for  the  equality  of  brightness  and  flicker  methods  by  1.2  ft. 
for  one  observer,  and  .8  ft.  for  another.  Wilde3  photometered 
a  tungsten  lamp  against  a  carbon  by  the  methods  of  flicker 
and  equality  of  brightness,  and  found  a  difference  of  6  per 
cent,  in  the  result.  Bell4  compared  the  ratio  of  lumin- 

1  Bell,  L.,  'Acuity  in  Monochromatic  Light,'  Electrical  World,  Sept.  9,  1911,  58, 
P-  637- 

'Whitman,  F.  P.,  'On  the  Photometry  of  Differently  Colored  Lights  and  the 
Flicker  Photometer/  Physical  Review,  1896,  3,  pp.  241-249. 

•Wilde,  L.  W.,  'The  Photometry  of  Differently  Colored  Lights,'  The  Electrician, 
July  16,  1909,  63,  pp.  540-541. 

4  Bell,  L.,  'Chromatic  Aberration  and  Visual  Acuity,'  Electrical  World,  May  II, 
1911,57,  pp.  1163-1166. 


FLICKER  PHOTOMETRY  H5 

osities  of  a  mercury  vapor  lamp  with  that  of  a  tungsten 
lamp  by  means  of  the  flicker  method  and  found  it  to  be  5.42. 
These  same  lights  by  the  equality  of  brightness  method  gave 
a  ratio  ranging  from  6.86  to  10.93  for  different  observers. 
Stuhr1  compared  red  and  green  lights  by  several  methods 
including  the  method  of  flicker  and  equality  of  brightness. 
He  found  that  the  mean  deviation  of  the  values  obtained  by 
the  method  of  flicker  from  those  obtained  by  the  equality  of 
brightness  method  amounted  to  14.14  per  cent.  Luckiesh2 
photometered  a  red  against  a  blue-green  light  by  the  methods 
of  flicker  and  equality  of  brightness,  and  found  a  difference  of 
62  per  cent,  in  the  ratios  of  the  luminosities  of  the  two  lights 
by  the  two  methods. 

Two  factors  have  in  the  main  been  assigned  to  the  cause 
of  the  disagreement:  the  effect  of  intensity  and  of  size  of  the 
photometric  field.  Lauriol,  Dow,  Millar,  Ives,  and  Luckiesh 
have  investigated  the  former  factor,  and  Schenck,  Dow,  and 
Ives  the  latter.  These  are  both  factors  which  affect  the 
results  of  both  methods.  In  comparison  little  attempt  has 
been  made  to  find  the  factors  that  affect  the  results  of  each 
method  alone.  As  a  general  case  these,  it  would  seem,  might 
be  more  apt  to  prove  a  source  of  disagreement  than  those 
which  affect  both  methods. 

With  regard  to  the  intensity  of  the  light  as  a  factor, 
Lauriol3  and  Dow4  claim  that  the  relative  shift  in  the  bright- 
ness of  the  different  colors  at  low  illuminations  is  shown  by 
both  methods.  The  shift  for  Dow,  however,  is  more  pro- 
nounced in  the  equality  of  brightness  than  the  flicker  deter- 
minations. For  Lauriol  the  shift  for  the  different  colors 
varies  in  magnitude  by  the  two  methods  and  in  some  cases 
in  direction.  Millar,5  on  the  other  hand,  claims  that  the 

1  Stuhr,  J.,  'Ueber  die  Bestimmung  des  Aequivalenzwertes  verschiedenfarbiger 
Lichtquellen,'  Kiel,  Philos.  Diss.,  Vol.  /p,  Okt.,  1908,  p.  50. 

2  Luckiesh,  M.,  'Purkinje  Effect  and  Comparison  of  Flicker  and  Equality  of 
Brightness  Photometers,'  Electrical  World,  March  22,  1913,  p.  620. 

3  Lauriol,   'Le   phptometre   a   papillotement  et  la   photometric   heterochrome,' 
Bull.  Soc.  Intern,  des  Electriciens,  1904,  pp.  647-652. 

4  Dow,  J.  S.,  'Color  Phenomena  in  Photometry,'  Philos.  Mag.,  1906,  12,  Ser.  6, 
p.  131. 

6  Millar,  P.  S.,  'The  Problem  of  Heterochromatic  Photometry,'  Trans.  Illuminating 
Engineering  Society,  1909,  4,  p.  769. 


146  C.  E.  FERREE  AND  GERTRUDE  RAND 

Purkinje  phenomenon  is  not  shown  at  all  by  the  flicker 
method  at  low  illuminations,  while  Ives1  and  Luckiesh2  go 
to  the  other  extreme  and  declare  that  a  reverse  Purkinje 
effect  is  obtained  by  the  flicker  method.  With  regard  to  size 
of  field  as  a  factor,  Schenck3  found  that  a  decrease  in  size 
lowered  the  mean  variation  for  the  flicker  method  and  de- 
creased the  luminosity  value  obtained  for  all  the  colors. 
Dow4  found  that  as  the  size  of  the  field  was  decreased,  red 
and  yellow  lightened  relatively  to  green  and  blue.  This 
effect  was  more  pronounced  for  the  equality  of  brightness 
than  for  the  flicker  method.  Ives5  found  this  effect  for  the 
equality  of  brightness  method,  but  the  reverse  effect  for  the 
flicker  method. 

Ives,  admitting  the  disagreement  between  the  two- 
methods  and  accepting  size  of  field  and  intensity  of  the 
stimulus  as  the  cause  of  the  disagreement,  sought  to  determine 
whether  a  field  size  and  intensity  could  not  be  found  for 
which  the  two  methods  agree.  He  photometered  different 
portions  of  the  spectrum  against  carbon  lamps  at  a  number  of 
intensities  and  with  a  number  of  field  sizes.  He  found  in 
general  for  five  observers  that  the  luminosity  curves  obtained 
by  each  method  differed.  This  difference,  however,  was  less 
for  high  intensities  than  for  low. 

A  table  is  appended  (Table  IX)  in  which  is  shown  in  per- 
centage the  difference  in  results  gotten  by  the  five  observers 
used  by  Dr.  Ives  at  the  intensity  of  light  which  he  calls  most 
favorable  to  agreement  for  the  two  methods  (250  Illumination 
Units).  It  will  be  seen  that  the  disagreement  for  these 
observers  is  in  the  average  as  great,  if  not  greater  than  was 
gotten  by  our  own  observers.  Percentage  of  overestimation 
by  the  method  of  flicker  is  designated  by  +,  and  under- 
estimation by  — . 

1  Ives,  H.  E.,  op.  cit.,  p.  171. 

*  Luckiesh,  M.,  op.  cit.,  p.  620. 

*  Schenck,  F.,  'Ueber  die  Bestimmung  der  Helligkeit  grauer  und  farbiger  Pigment- 
papiere  mittels  intermittirende  Netzhautreizung,'  Pfliiger's  Archiv,  1896,  64,  pp.  607- 
628. 

«Dow,  J.   S.,  op.  cit.,  pp.    130-134;  'Physiological  Principles  Underlying  the 
Flicker  Photometer,'  Philos.  Mag.,  1910,  jp,  Ser.  6,  pp.  58-77. 
6  Ives,  H.  E.,  op.  cit.,  p.  172. 


FLICKER  PHOTOMETRY 


747 


TABLE  IX 

Showing  in  percentage  the  difference  in  results  between  the  methods  of  flicker  and 

equality  of  brightness  for  the  five  observers  used  by  Dr.  Ives  at  the  intensity 

of  light  which  he  calls  most  favorable. 


\ 

H.  E.  I. 

M.L. 

P.  W.  C. 

C.  F.  L. 

F.  E.  C. 

•653M 

-12.    % 

+  29-    % 

-18.  % 

-Si-  % 

-50.  % 

.643^ 

-    3-6 

+  56. 

-  7.0 

-31. 

-23-7 

.63  2/t 

-  4-3 

+  20. 

-iS-5 

-45-5 

-12.9 

.622/1 

-  7-3 

+  I2.S 

-  4.2 

-42. 

-iS-9 

.612^1 

—  10. 

+    8.3 

-  6.5 

-  7-5 

+  0.3 

•594M 

—  i. 

~    0.5 

-  0.5 

+  7-5 

+  5-8 

•574M 

+  0.5 

-    2.4 

-  2.5 

+27. 

-  5-9 

•555M 

-  0.4 

-  8.0 

-ii,Q 

-  4-8 

+  8.9 

•545M 

-  3-i 

-  8.4 

-13.8 

+  3- 

+  8. 

.536^ 

-  1-9 

-  4.0 

-12.6 

—  12. 

+  14-3 

.526/11 

0 

-  8.7 

-21.4 

-  3- 

•4-33-5 

•5I7/* 

+  0.6 

—  10.8 

-13.8 

-33- 

+30.0 

It  has  been  our  purpose  in  general  in  this  part  of  the 
paper  to  indicate  a  field  of  investigation  in  the  department 
of  physiological  optics  about  which  little  is  known  as  yet  with 
certainty,  rather  than  to  report  a  finished  piece  of  work  or  to 
attempt  to  draw  positive  conclusions.  When  functioning 
under  the  conditions  imposed  by  the  method  of  flicker,  too 
little  is  known  of  the  characteristics  of  the  eye,  we  believe, 
to  render  safe  its  use  as  a  measuring  instrument.  Our 
purpose  in  particular  has  been  to  point  out  and  show  the  effect 
of  a  factor  which  we  believe  to  be  an  important  source  of 
disagreement  between  the  equality  of  brightness  and  the 
flicker  methods,  and  to  suggest  that  a  more  careful  study  be 
made  of  the  factors  that  influence  the  method  of  flicker  before 
it  is  adopted  in  its  present  form  as  the  method  for  the  stan- 
dardizing laboratories.  Just  as  one  factor  has  been  over- 
looked, so  there  may  be  others  the  influence  of  which  should 
not  be  ignored. 

APPENDIX 

Three  other  points  which  may  be  of  interest  in  connection 
with  the  above  work  are  appended  here.  The  first  two  were 
discussed  by  Dr.  Ives  in  a  series  of  articles  on  the  method  of 
flicker  in  the  Philos.  Mag.,  1912,  24,  Ser.  6,  pp.  149-188, 
352-370,  744-751,  845-853,  853-863.  (i)  In  the  third  of  his 
series  of  articles,  he  apparently  wishes  to  show  that  the  cause 


148  C.  E.  FERREE  AND  GERTRUDE  RAND 

of  the  disagreement  between  the  results  of  the  methods  of 
flicker  and  equality  of  brightness  lies  on  the  side  of  the  latter 
method.  That  is,  the  difficulty  of  making  the  judgment  is  so 
great  that  not  an  equalization,  only  an  'appraisement'  is 
accomplished.  To  demonstrate  this,  he  attempts  to  get  rid 
of  the  disturbing  factor  of  color  difference  in  the  equality  of 
brightness  method  by  making  his  comparisons  always  between 
lights  differing  only  slightly  in  composition.  That  is,  a 
green  is  compared  with  a  green  slightly  shifted  toward  the 
yellow  or  blue,  etc.  (See  his  work  with  the  'cascade' 
method,  p.  748.)  A  curve  of  luminosity  for  the  spectrum 
obtained  in  this  way  is  found  to  agree  more  closely  with  the 
flicker  curve  than  one  obtained  in  the  ordinary  way.  The 
following  things  may  be  said  of  this  demonstration,  however. 
In  the  first  place,  he  states  that  the  cumulative  errors  are  so 
great  in  the  method  that  he  could  not  begin  at  one  point  in 
the  spectrum  having  a  given  luminosity  and  work  in  a  given 
direction,  then  reverse  this  direction  of  working  and  obtain 
at  all  a  close  approximation  to  the  luminosity  value  for  the 
point  at  which  he  started.  For  this  reason  he  drops  the 
point  by  point  procedure  of  the  'cascade'  method,  and  plots 
his  curve  by  taking  his  observations  at  twelve  points  in  the 
spectrum.  From  the  observations  of  these  points  the  whole 
curve  is  constructed.  In  the  second  place,  his  method  does 
not  entirely  accomplish  his  purpose  of  getting  rid  of  all  differ- 
ence in  color  quality  between  the  lights  compared.  In  order 
to  add  some  further  data  bearing  upon  the  question  whether 
the  lack  of  agreement  hitherto  found  between  the  results 
obtained  by  the  equality  of  brightness  and  flicker  methods 
could  have  been  due  to  the  difficulty  of  making  the  equality 
of  brightness  judgments  of  fields  differing  in  color  quality, 
we  have  thought  it  worth  while  to  make  the  comparison 
using  an  equality  of  brightness  method  which  for  the  pur- 
poses of  this  investigation  presents,  we  believe,  some  points 
of  advantage  over  the  method  used  by  Dr.  Ives.1  That  is, 

*We  do  not,  however,  mean  to  propose  this  as  an  entirely  satisfactory  method 
of  heterochromatic  photometry  for  the  reason  given  in  the  discussion  of  the  relation 
of  the  method  to  the  Talbot-Plateau  law  (see  footnote  p.  149).  We  are  using  the 
method  heie  merely  to  show  that  when  the  disturbing  factor  of  color  difference  in  the 


FLICKER  PHOTOMETRY  H9 

the  method  we  have  used  offers  even  less  chances  for  errors 
in  judgment,  is  simpler,  and  entirely  eliminates  the  presence 
of  a  second  color  in  the  fields  to  be  compared.  The  method 
is  as  follows:  The  sectored  disc  was  adjusted  so  that  its 
outer  edge  bisected  vertically  the  photometric  field.  A 
standard  colorless  light  was  moved  to  the  position  on  the 
photometer  bar  that  gave  the  judgment  of  equality  by  the 
method  of  flicker,  and  the  disc  was  rotated  at  the  fusion  rate. 
Half  of  the  field  was  thus  of  color  of  the  original  saturation 
and  luminosity,  and  the  other  half  was  a  fusion  of  the 
colored  sector  of  the  original  saturation  and  luminosity  and  a 
gray  sector  of  the  luminosity  of  the  color  as  determined  by 
the  method  of  flicker.  Now,  if  the  luminosity  of  the  color  by 
the  method  of  flicker  were  the  same  as  by  the  equality  of 
brightness  method,  the  two  halves  of  the  photometric  field 
should  match  in  luminosity  (within  the  limits  imposed  by  the 
Talbot-Plateau  law).1  That  is,  the  addition  of  the  colorless 

fields  to  be  compared  is  eliminated  from  the  equality  of  brightness  method,  there  is 
still  a  large,  in  fact  an  apparently  undiminished  characteristic  difference  between 
the  results  of  the  equality  of  brightness  and  flicker  methods,  which,  so  far  as  one 
can  see,  can  in  no  way  be  ascribed  to  the  equality  of  brightness  method  employed. 
The  degree  to  which  the  influence  of  color  difference  on  the  judgment  of  the  bright- 
ness equality  of  the  fields  compared  is  removed  by  this  method  is  shown  by  the  greatly 
increased  reproducibility  of  the  judgment.  For  our  observers,  the  reproducibility 
is  almost  as  great  as  it  was  for  the  method  of  flicker.  There  was  thus  but  little  more 
of  the  element  of  appraisement  in  this  method  than  there  was  in  the  method  of  flicker, 
while  the  characteristic  difference  in  the  results  obtained  by  the  two  methods  was  not, 
so  far  as  could  be  determined,  appreciably  lessened. 

1 A  few  words  are  needed  to  explain  what  is  meant  above  by  "within  the  limits 
imposed  by  the  Talbot-Plateau  law."  It  could  scarcely  be  expected  from  a  considera- 
tion of  this  law  that  the  two  fields  would  match  especially  under  the  dark-room  condi- 
tions under  which  photometry  is  done,  even  when  the  gray  sector  was  chosen  equal  in 
brightness  to  the  color  by  the  equality  of  brightness  method.  That  is,  when  the 
colored  is  mixed  with  the  gray  sector  by  the  method  of  successive  impressions,  there 
is  a  reduction  of  the  intensity  of  each  impression  which  is  the  same  as  would  be 
gotten  were  the  intensity  of  each  light  to  be  reduced  in  proportion  to  the  time  of  ex- 
posure of  the  eye  to  each  light  to  the  total  time  of  exposure  of  the  eye  to  both  lights. 
(See  the  discussion  of  the  Talbot-Plateau  law,  p.  121.)  That  is,  if  the  value  of  each 
sector  is  180°,  the  impression  made  upon  the  eye  by  each  light  is  the  same,  according 
to  the  Talbot-Plateau  law,  as  if  both  lights  were  reduced  one-half  in  intensity.  But 
in  suffering  the  reduction,  the  luminosity  of  the  colored  sector  is  not  changed  the  same 
in  amount  as  is  that  of  the  gray  sector.  If  it  is  blue  or  green,  for  example,  its  bright- 
ness is  not  reduced  so  much  as  is  that  of  the  gray  sector,  and  its  fusion  with  the  gray 
sector  tends  to  lighten  that  sector  and  to  make  the  second  half  of  the  field  lighter  than 


150  C.  E.  FERREE  AND  GERTRUDE  RAND 

to  the  colored  sector  would  produce  no  change  in  its  luminos- 
ity, and  the  two  halves  of  the  field  would  present  a  fully 
saturated  color  of  a  given  luminosity  and  a  less  saturated 
color  of  the  same  luminosity  (within  the  limits  imposed  above). 
But  if  there  were  an  underestimation  or  an  overestimation  of 
the  luminosity  of  the  color  by  the  method  of  flicker,  the 
brightness  of  the  second  half  of  the  field  would  be  modified 
in  this  direction  in  proportion  to  the  value  of  the  colored  and 
colorless  sector;  and  if  the  underestimation  or  overestimation 
were  great  enough  the  two  halves  would  not  match.  In 
proportion  as  the  colorless  sector  is  made  larger  in  the  second 
half  of  the  field,  the  color  of  the  mixture  loses  saturation,  and 
the  comparison  with  the  fully  saturated  half  of  the  fields 
becomes  more  difficult  to  make.  On  the  other  hand,  in 
proportion  as  the  colored  sector  is  made  larger,  the  effect  on 
the  brightness  of  the  mixture,  of  the  difference  between  the 
flicker  value  and  the  true  sensation  value,  if  such  a  difference 
exists,  is  lost.  After  considerable  preliminary  investigation 
it  was  decided  to  use  in  turn  colored  sectors  of  the  value  of 
300°,  270°,  and  1 80°.  The  comparison  was  made  for  lights 
of  the  intensities  specified  in  the  preceding  sections  of  the 
paper.  In  all  cases  when  the  color  was  red  or  yellow,  the 

the  first.  If,  however,  the  colored  sector  is  red  or  yellow,  it  is  reduced  more  in  bright- 
ness than  is  the  gray  sector,  and  its  fusion  with  that  sector  tends  to  darken  it  and  so 
to  render  the  second  half  of  the  photometric  field  darker  than  the  first.  We  have 
conducted  experiments  to  determine  whether  the  above  effect,  which  is  a  direct  corol- 
lary of  the  Talbot-Plateau  law,  actually  takes  place  in  observable  amounts.  When 
the  light  of  the  spectrum  or  light  of  the  purity  given  by  the  Wratten  and  Wainwright 
filters  was  used,  we  found  that  it  did.  That  is,  when  the  second  half  of  the  field  was 
green  or  blue  and  was  fused  with  a  gray  of  the  luminosity  of  the  color  employed, 
determined  by  the  equality  of  brightness  method,  this  half  of  the  field  was  observably 
lighter  than  the  first  half.  Conversely,  when  red  or  yellow  was  used,  the  second  half 
of  the  field  was  darker  than  the  first.  The  effect,  however,  was  not  nearly  so  great  as 
it  was  when  the  gray  sector  was  made  of  the  brightness  of  the  color  as  determined 
by  the  method  of  flicker.  That  is,  if  two  experiments  are  conducted,  one  in  which 
the  second  half  of  the  field  is  made  by  fusing  the  colored  sector  with  a  gray  sector 
of  the  brightness  of  the  color  as  determined  by  the  equality  of  brightness  method,  and 
the  other  in  which  this  half  of  the  field  is  made  by  fusing  the  colored  sector  with  a  gray 
sector  of  the  brightness  of  the  color  as  determined  by  the  method  of  flicker,  the  differ- 
ence in  brightness  between  the  two  halves  of  the  field  is  quite  appreciably  greater 
in  the  second  case  than  in  the  first.  For  example,  when  the  colors  are  green  and  blue, 
the  second  half  of  the  field  is  more  too  light  in  the  second  case  than  in  the  first;  and 
when  red  and  yellow,  it  is  more  too  dark. 


FLICKER  PHOTOMETRY  I51 

second  half  of  the  field  was  darker  than  the  first;  and  when 
either  blue  or  green,  was  lighter  than  the  first  half  of  the  field. 
Determinations  were  made  also  of  how  much  the  colorless 
light  had  to  be  moved  to  make  the  two  halves  of  the  field 
match.  These  distances  were  not  much  different  from  those 
contained  in  the  tables  in  the  preceding  sections  of  the  paper 
expressing  the  difference  in  the  estimation  of  the  luminosity  of 
the  colors  by  the  methods  of  flicker  and  equality  of  brightness 
(see  pp.  136,  137), — certainly  not  any  more  than  should  be 
expected  when  it  is  remembered  that  a  part  of  the  effect 
of  the  difference  is  lost  by  mixing  the  colorless  light  repre- 
senting the  flicker  determination  with  a  sector  of  the  colored 
light  in  its  true  luminosity  value.  The  work  was  done  also 
with  pigment  papers  with  a  similar  result.  Thus  it  seems 
reasonable  to  conclude  that  the  cause  of  the  disagreement 
between  the  two  methods  can  not  be  attributed  entirely  at 
least  to  the  difficulty  of  making  the  equality  of  brightness 
judgment  due  to  the  difference  in  color  quality  between  the 
fields  compared,  for  in  the  above  cases  the  color  quality  of 
the  lights  compared  was  the  same.  In  the  third  place,  dis- 
regarding the  results  of  the  above  experiments,  the  writers 
scarcely  need  point  out  that  it  would  be  extremely  difficult 
to  explain  such  a  systematic  drift  of  luminosity  in  one  direc- 
tion in  one  part  of  the  spectrum,  and  in  the  opposite  direction 
in  the  other  part,  as  we  obtained,  in  terms  of  errors  due  to  a 
false  judgment  of  the  sensations  actually  aroused.  More- 
over, it  would  be  just  as  difficult  to  explain  Dr.  Ives's  own 
reverse  Purkinje  effect  in  terms  of  a  false  judgment  of  the 
actual  brightness  values  presented  in  sensation;  or  the  closer 
agreement  he  obtains  between  the  results  by  the  methods  of 
flicker  and  equality  of  brightness  at  high  illuminations,  in 
which  case  there  is  the  maximum  amount  of  color  present 
and,  therefore,  the  maximum  color  difference  to  disturb  the 
equality  of  brightness  judgment  between  colored  and  color- 
less light.  Moreover,  the  kind  of  errors  that  one  finds  as 
due  to  uncertainty  of  judgment  is  a  deviation  on  either  side  of 
a  mean.  This  occurs  when  all  other  factors  are  eliminated  if 
several  judgments  of  the  same  sensation  are  made.  Such 


152  C.  E.  FERREE  AND  GERTRUDE  RAND 

errors  are  compensated  for  by  taking  the  average  or  mean  of 
the  determinations.  If  it  is  not  conceded  that  they  are  com- 
pensated for,  how,  for  example,  can  the  average  of  the  results 
by  the  equality  of  brightness  method  be  taken  as  a  standard 
in  terms  of  which  to  evaluate  the  results  obtained  by  other 
methods?  (See  Whitman,  Schenck,  Wilde,  etc.).1  Surely 
this  should  not  be  allowed  if  there  were  a  consistent  deviation 
in  any  one  direction  from  the  true  brightness  value  for  a  given 
color  due  to  errors  in  judgment.  Moreover,  such  a  character- 
istic drift  due  to  errors  in  judgment  is  unknown  in  all  previous 
work  in  psychophysics,  and  not  only  unknown,  but  unsus- 
pected. 

(2)  In  the  fourth  paper  of  the  series,2  Dr.  Ives  applies  as 
a  test  to  the  method  of  flicker  what  he  calls  two  axioms  of 
measurement.     These  are  (a)  things  which  are  equal  to  the 
same  things  shall  be  equal  to  each  other;  and  (b)  the  whole 
shall  be  equal  to  the  sum  of  its  parts.     He  finds  that  the 
method  of  flicker  satisfies  these  axioms  better  than  the  equali- 
ty of  brightness  method.     We  would  point  out  that  these 
tests  would  not  be  expected  to  reveal  to  any  considerable  de- 
gree the  influence  of  the  factor  we  are  discussing.     They  are 
tests  which  would  apply  as  a  check  on  the  power  to  make  the 
judgment  of  the  brightness  of  the  sensation  properly,  or  to 
any  tendency  of  this  brightness  equality  to  drift  in  one  direc- 
tion in  any  part  of  the  spectrum  without  a  compensating  drift 
in  the  opposite  direction  in  some  other  part  of  the  spectrum; 
but  they  are  not  tests  that  could  be  expected  to  show  whether 
or  not  there  is   underestimation  in  one  half  of  the  spectrum 
and  overestimation  in  the  other  half.     For  example,  the  area 
of  the  curve  of  the  spectrum  plotted  by  the  method  of  flicker 
might  very  well  sum  up  to  the  value  of  the  reassembled  white 
light  because  of  the  compensating  effect  of  the  underesti- 
mation of  one  half  of  the  spectrum  and  the  overestimation  of 
the   other   half. 

(3)  Since  the  foregoing  paper  was  presented,  the  writers 

1  While  Dr.  Ives  does  not  explicitly  state  that  he  takes  the  equality  of  brightness 
method  as  a  standard  in  terms  of  which  to  evaluate  the  correctness  of  the  results  by 
other  methods,  the  point  of  view  is  strongly  implied  in  his  first  paper  (loc.  cit.). 

*Philos.  Mag.,  1912,  24,  Ser.  6,  pp.  845-853. 


FLICKER  PHOTOMETRY  *53 

have  met  with  the  contention  from  a  prominent  advocate  of 
the  method  of  flicker  that  the  effect  of  a  reduction  of  intensity 
is  not  given  by  the  method  of  flicker  because  each  individual 
impression  is  carried  over  until  the  next  is  given,  with  suffi- 
cient intensity  to  preclude  the  effect  of  reduction.  Whether 
or  not  each  individual  impression  can  be  considered  as  carry- 
ing over  with  sufficient  intensity  to  preclude  the  effect  of  re- 
duction is  an  important  point  and  should,  lest  the  issue  be  in 
doubt,  be  included  in  a  discussion  of  the  principles  underlying 
the  method  of  flicker.  It  may  not  be  out  of  place,  therefore, 
for  us  to  consider  the  question  here  briefly,  even  though  it 
has  not  as  yet,  so  far  as  we  know,  been  discussed  in  print. 
As  evidence  that  each  individual  impression  should  be 
considered  as  carrying  over  with  sufficient  intensity  to  pre- 
clude the  effect  of  reduction,  it  was  contended,  as  the  case 
was  presented  to  us,  that  the  rate  used  in  the  method  of  flicker 
is  the  fusion  rate  of  the  two  impressions.  Two  reasons  were 
given  for  considering  this  rate  as  the  fusion  rate,  (i)  If  the 
two  impressions  be  red  and  green,  for  example,  yellow  is  pro- 
duced at  the  rate  of  succession  used  in  the  flicker  method. 
Yellow,  it  was  pointed  out,  is  a  fusion  of  red  and  green,  and, 
therefore,  the  rate  used  must  be  considered  as  the  fusion  rate 
for  these  colors.  In  answer  to  this  point  we  would  again  call 
attention  to  the  phenomena  (see  p.  116)  which  are  produced  in 
sensation  when  two  impressions  differing  in  color  and  bright- 
ness are  given  to  the  eye  successively  at  different  rates  of 
speed.1  When  the  rate  is  very  slow,  the  effect  of  separate 
and  distinct  impressions  is  given,  each  in  its  proper  color  and 
brightness.  When  a  little  faster  rate  is  used,  the  impressions 
become  confused  and  a  flickering  effect  is  produced  both  in 
the  color  and  brightness  components  of  the  sensation.  When 
the  rate  is  made  still  faster,  the  flickering  of  color  dies  out, 
leaving  only  brightness  flicker;  that  is,  the  color  components 
of  the  two  sensations  have  been  fused.  That  the  brightness 

1  We  wish  at  this  point  to  state  very  emphatically  that  our  account  of  the  fusion 
of  the  color  and  brightness  components  of  sensation  at  different  rates  of  speed  is  not 
based  on  any  theoretical  conception  of  a  separate  brightness  and  color  sense,  but  upon 
actual  observation  of  the  phenomena  that  take  place  when  light  impressions  differing 
in  color  and  luminosity  are  combined  at  different  rates  of  succession.  These  phe- 


154  C.  E.  FERREE  AND  GERTRUDE  RAND 

components  have  not  been  fused,  however,  is  attested  by  the 
presence  of  brightness  flicker,  which  is  now  left  outstanding 
in  a  field  uniform  as  to  color  quality.  As  the  rate  of  succes- 
sion is  made  still  faster,  brightness  flicker  becomes  less  and 
less  pronounced  and  finally  disappears.1  The  rate  at  which 
this  disappearance  takes  place  is  the  fusion  rate  for  the  bright- 
ness components  for  the  two  sensations,  and  is  much  higher 
for  all  the  colors  than  is  the  rate  at  whieh  the  fusion  of  the 
color  components  takes  place.2  (Interpreted  in  terms  of  the 

nomena  may  be  readily  demonstrated  by  any  kind  of  flicker  photometer  head  if  a 
sufficiently  sensitive  control  of  speed  of  rotation  is  had.  (We  have  used  for  the  control 
of  speed  of  rotation  a  rheostat  and  motor  especially  constructed  to  give  fine  changes.) 
It  can  be  very  plainly  and  perhaps  most  conveniently  demonstrated  by  rotating 
sectors  of  pigment  papers  at  the  proper  gradations  of  speed  in  a  good  daylight  illu- 
mination. 

!We  find  that  Kriiss  (Physical  Zeitschr.,  1904,  5,  p.  67)  gives  a  description  of 
the  phenomena  that  take  place  in  sensation  when  two  impressions  differing  in  color 
and  brightness  are  given  to  the  eye  successively  at  different  rates  of  speed,  very 
similar  to  that  we  have  given  here.  He  says :  "  If  we  slowly  alternate  the  illumination 
from  two  differently  colored  light  sources,  for  example,  from  a  Hefner  lamp  and  a  gas 
burner,  we  clearly  distinguish  a  succession  of  reddish  and  bluish  bands  with  weak 
washed-out  limits  between  them.  As  the  rate  of  succession  is  increased  it  becomes 
progressively  more  difficult  to  distinguish  the  two  colors  from  each  other.  At  a  com- 
paratively low  rate  they  begin  to  lose  themselves  in  each  other.  At  a  slightly  higher 
rate  the  difference  in  color  disappears  altogether  and  we  have  a  color  mixture.  In  this 
mixture,  however,  a  brightness  succession,  a  flicker,  is  observable  which  disappears 
only  by  a  further  increase  in  the  rate  of  succession.  Physiologically,  it  is  of  great 
interest  that  the  distinguishing  of  separate  colors  ceases  at  a  much  slower  rate  of 
succession  than  the  rate  at  which  completely  continuous  sensation  begins." 

2  The  following  values  will  serve  to  give  a  rough  comparative  showing  of  the 
rates  at  which  the  phenomena  described  above  take  place.  The  colors  used  were  red 
and  green.  They  were  obtained  from  pigment  papers  of  the  Hering  series  of  standard 
papers  and  from  gelatine  filters.  Two  intensities  of  color  were  employed  in  each  case. 
The  brightness  of  the  Hering  green  for  the  lower  intensity  of  illumination  was  .000814 
cp.  per  sq.  in.;  of  the  red,  .000594  CP-  Per  scl'  m-  The  phenomenon  of  separate 
impressions  occurred  from  the  lowest  speed  up  to  6.9  revolutions  per  second.  The 
impression  of  an  intermingled  color  and  brightness  flicker  was  given  from  this  rate 
up  to  9.6  revolutions  per  second,  at  which  rate  the  color  components  of  the  sensation 
fused,  giving  a  field  uniform  as  to  color  quality  but  with  a  strong  outstanding  brightness 
flicker.  Brightness  flicker  was  present  until  a  speed  of  22  revolutions  per  second  was 
obtained.  At  this  speed  the  brightness  components  in  sensation  were  completely 
fused  and  the  rotating  disc  presented  a  surface  uniform  both  as  to  color  and  brightness. 
In  making  these  determinations,  the  same  sized  field  was  used  as  was  employed  in  our 
work  with  the  method  of  flicker,  i.  e.,  the  disc  was  viewed  through  an  aperture  3  mm. 
X  3  mm-  in  a  gray  screen  (Hering  No.  24)  20  cm.  from  the  eye.  For  the  higher  inten- 
sity the  green  surface  was  illuminated  to  a  brightness  of  .00242  cp.  per  sq.  in.;  the 


FLICKER  PHOTOMETRY  155 

duration  of  the  impression  after  the  light  has  been  cut  off, 
this  means,  of  course,  that  the  brightness  component  in  the 
sensation  does  not  carry  over  under  these  conditions  with  as 
little  loss  of  intensity  as  does  the  color  component.)  It  is 
evident,  then,  that  the  rate  of  succession  which  is  used  in  the 
method  of  flicker  is  at  or  near  the  fusion  rate  for  the  color 
components  of  the  two  sensations,  not  for  the  brightness  com- 
ponents; nor  is  it  anywhere  near  the  fusion  rate  for  the  bright- 
ness components.  But  it  is  the  brightness  components  in 
which  we  are  interested  in  photometry.  That  is,  it  is  in 
terms  of  the  brightness  component  that  all  photometric  judg- 
ments are  made.  The  color  components,  when  they  differ 
in  tone,  only  serve  to  confuse  the  judgment.  It  is,  therefore, 
our  object  in  all  methods  of  photometry  as  much  as  possible 
to  get  rid  of  difference  in  the  color  components.  This  can  be 
accomplished  in  the  method  of  flicker  only  because  of  the 
fact  we  have  just  pointed  out,  namely,  that  the  fusion  of  the 
color  component  in  sensation  comes  at  a  much  lower  rate  of 
succession  than  the  fusion  of  the  brightness  component.  That 
is,  all  color  differences,  whether  sensed  as  distinct  or  as  flicker- 
ing sensations,  disappear  at  a  rate  of  succession  that  has  little 
or  no  effect  on  eliminating  the  brightness  factor,  or  in  this 
case  the  equivalent  of  this  elimination,  the  fusion  of  the  bright- 
ness components  of  the  two  sensations.  In  fact,  if  there 
were  no  difference  in  the  fusion  rate  of  the  color  and  bright- 
ness components,  the  flickering  color  impressions  would  so 
mask  the  presence  of  brightness  flicker  at  any  rate  of  succes- 
sion that  could  be  used,  that  the  method  would  doubtless 

red,  .00167  CP-  per  sq.  in.  The  phenomenon  of  separate  impressions  occurred  from 
the  lowest  speed  -to  6  revolutions  per  second,  at  which  rate  color  flicker  began.  Color 
fusion  took  place  at  12.4  revolutions  per  second,  and  brightness  fusion  at  29.3  revolu- 
tions per  second.  At  the  lower  intensity  for  the  filters,  the  brightness  of  the  green 
was  .154  cp.  per  sq.  in.;  for  the  red,  .099  cp.  per  sq.  in.  As  compared  with  their 
brightness  these  colors  were  much  more  poorly  saturated  than  were  the  Hering  pig- 
ments. The  phenomenon  of  separate  impressions  ceased  and  color  flicker  began  at 
6.5  per  second.  Color  fusion  took  place  at  11.5  revolutions  per  second,  and  brightness 
fusion  took  place  at  35.4  revolutions  per  second.  At  the  higher  intensity  for  the 
filters  the  brightness  of  the  green  was  .22  cp.  per  sq.  in.;  for  the  red,  .143  cp.  per 
sq.  in.  Color  flicker  began  at  7  revolutions  per  second;  color  fusion  took  place  at 
12.9  revolutions  per  second;  and  brightness  fusion  was  complete  at  38.3  revolutions 
per  second. 


156  C.  E.  FERREE  AND  GERTRUDE  RAND 

have  little  if  any  greater  sensitivity  than  the  equality  of 
brightness  method.  (2)  The  second  point  that  was  cited 
in  support  of  the  contention  that  the  rate  used  in  the  method 
of  flicker  is  the  fusion  rate  for  the  two  sensations  aroused,  is 
that  no  brightness  flicker  is  present  when  in  terms  of  the 
method  the  two  impressions  are  adjudged  of  the  same  bright- 
ness. This  to  the  present  writers  seems  indeed  a  strange 
confusion  of  meanings.  Fusion  is  a  term  used  to  represent 
what  takes  place  when  two  impressions  or  sensations  differing 
in  quality  are  combined  into  one,  the  same  or  homogeneous 
as  to  quality.  This  combination  may  be  obtained  in  case  of 
light  stimuli,  for  example,  by  mixing  two  lights  evenly  and 
allowing  them  to  act  simultaneously  on  the  eye;  or  it  may  be 
obtained  by  giving  two  lights  to  the  eye  in  succession  at  such 
a  rate  that  the  sensation  aroused  by  the  one  lasts  over  until 
the  next  one  is  set  up  with  a  sufficient  degree  of  intensity  to 
give  the  effect  of  continuity  or  homogeneity  of  quality.  It 
may  add  to  the  clearness  of  our  discussion,  then,  to  consider 
what  takes  place  in  this  regard  when  two  impressions  differing 
in  brightness  are  given  to  the  eye  at  the  different  rates  of 
succession  mentioned  in  the  preceding  paragraph.  At  the 
rate  at  which  distinct  and  separate  impressions  are  given, 
each  sensation  obviously  dies  away  completely  before  the 
next  one  is  aroused.  If  a  rate  slightly  faster  than  this  is 
selected,  the  sensation  does  not  die  away  completely  before 
the  next  one  is  set  up. 

There  is  a  slight  lasting-over  from  one  impression  to  the 
next.  This  when  the  two  impressions  differ  in  brightness 
gives  the  effect  of  a  wavering  or  flickering  sensation.  At  the 
lowest  speed  at  which  flicker  is  produced,  the  effect  of  this 
lasting-over  has  its  minimum  value.  As  the  speed  is  further 
increased  it  becomes  greater  and  attains  its  maximum  value 
at  the  rate  of  complete  brightness  fusion.1  (See  discussion  of 
Talbot-Plateau  law,  pp.  121.)  It  is  obvious,  then,  that  the 
rate  of  speed  employed  in  the  method  of  flicker,  which  is, 
roughly  speaking,  the  lowest  rate  at  which  brightness  flicker 

1  At  the  fusion  rate  neither  sensation  rises  to  its  maximum  value,  for  example,  nor 
has  a  chance  to  die  away  until  the  next  one  develops.  The  effect  is  that  of  a  con- 
tinuous sensation  homogeneous  as  to  color  and  brightness. 


FLICKER  PHOTOMETRY  157 

can  be  obtained  unmixed  with  color  flicker,  is  not  the  fusion 
rate  for  the  brightness  components  in  sensation  nor  is  it 
anywhere  near'  this  rate.1  It  is  equally  obvious  also  that  the 
absence  of  flicker  when  the  final  adjustment  of  the  lights  has 
been  made  for  a  photometric  balance,  can  not  be  adduced  as 
any  evidence  that  this  rate  is  the  fusion  rate  for  the  brightness 
component  of  the  two  sensations,  or,  what  is  more  significant 
in  relation  to  the  above  mentioned  claim,  that  it  is  a  rate  to 
which  more  than  a  minimum  of  lasting-over  effect  from 
impression  to  impression  can  be  ascribed.  Flicker  is  absent 
merely  because,  in  accord  with  the  purpose  of  the  method, 
such  an  adjustment  of  the  distance  of  the  lights  from  the 
photometer  head  is  made  that  the  sensations  aroused  by  the 
two  lights  are  of  equal  brightness.  Such  sensations  do  not 
flicker  whatever  may  be  their  rate  of  succession.  It  can, 
therefore,  be  considered  as  little  more  than  absurd  to  adduce 
the  absence  of  flicker  when  the  photometric  balance  has  been 
attained  as  evidence  that  the  rate  used  is  the  fusion  rate  for 
the  brightness  components  of  sensation,  and  to  pass  from  this 
to  the  conclusion  that  the  same  amount  or  anywhere  near  the 
same  amount  of  carrying-over  effect  is  present  for  this  rate 
as  obtains  when  the  fusion  rate  is  used.  In  fact,  if  this 
carrying-over  effect  were  present  to  any  considerable  degree, 
the  whole  point  of  the  flicker  method  would  be  lost.  That 
is,  it  is  the  purpose  in  the  method  of  flicker  to  select  a  rate  of 
succession  that  will  give  the  eye  the  maximum  of  sensitivity 
to  brightness  difference  (or  flicker),  namely,  the  lowest 
rate  at  which  flicker  can  be  produced,  rather  than  a  rate  that 
will  fuse  out  this  difference  in  sensation. 

But  supposing  it  could  be  established,  as  was  contended, 
that  we  have  in  the  rate  used  in  the  method  of  flicker  a  com- 
plete color  and  brightness  fusion  of  the  sensations  aroused 
by  the  two  lights,  little  would  be  gained  for  the  claim  that 
there  is  no  reduction  in  the  effect  on  sensation  of  the  two 
lights  employed,  if  it  be  granted,  for  example,  that  the 
Talbot-Plateau  law  is  true.  In  substance  this  law  is  as 

1  Flicker  and  fusion  are  in  fact  antithetical  terms,  and  the  rates  of  succession 
which  are  favorable  for  each  are  widely  separated  in  the  scale  of  frequencies. 


158  C.  E.  FERREE  AND  GERTRUDE  RAND 

follows.  When  once  the  rate  of  rotation  is  sufficient  to  give 
a  uniform  sensation,  the  color  and  brightness  of  the  disc  are 
the  same  as  they  would  be  if  all  the  light  reflected  from  the 
sectors  were  evenly  distributed  over  the  surface  of  the  disc; 
and  no  further  increase  in  rapidity  produces  any  effect  on  its 
appearance.1  In  terms  of  this  law  it  is  seen  that  the  effect  on 

1  See  H.  F.  Talbot,  'Experiments  on  Light/  Philos.  Mag.,  1834,  Ser.  3,  5,  pp.  321- 

334- 

Talbot  phrases  this  law  as  follows  (pp.  328-329):  "Since  then  these  two  things — 
the  intensity  of  light  and  the  time  of  the  body's  remaining  in  any  given  part  of  the 
circle — are  each  inversely  proportional  to  the  circumference  of  the  circle  it  describes, 
it  follows  that  they  must  be  directly  proportional  to  each  other;  that  is  to  say,  an 
irregular  intermittent  luminary  whose  observations  are  too  frequent  and  too  transitory 
for  the  eye  to  perceive,  loses  so  much  of  its  apparent  brightness  from  this  cause  as  is 
indicated  by  the  proportion  between  the  whole  time  of  observation  and  the  time 
during  which  it  disappears."  "The  rapidity  of  the  rotation  does  not  affect  the  argu- 
ment." To  verify  this  reasoning,  Talbot  conducted  experiments  with  reflected  light 
using  pigment  surfaces  and  mirrors  to  send  the  light  to  the  eye;  and  with  transmitted 
light  using  sectored  discs  to  cut  down  the  time  of  exposure  of  the  eye  to  various  luminous 
sources. 

In  1835  Plateau  repeats  and  verifies  Talbot's  experiments.  (*  Betrachtungen 
fiber  ein  von  Hrn.  Talbot  vergeschlagenes  photometrisches  Princip,'  Poggen.  Annal, 
1835,  35,  pp.  457-468).  He  concludes  from  his  experiments  as  follows  (pp.  462-463) 
"Nun  muss  zufolge  des  am  Anfange  dieses  Aufsatzes  dargelegten  Princips  die  schein- 
bare  Helligkeit  der  Scheibe  sich  zu  der  des  Papiers  verhalten  wie  die  Voriibergangsdauer 
eines  weissen  und  eines  schwarzen  Sectors;  odor  was  dasselbe  ist,  wie  die  Winkelbreiten 
eines  weissen  Sectors  zur  Summe  der  Winkelbreiten  eines  weissen  und  schwarzen 
Sectors,  oder  endlich,  was  auch  noch  dasselbe  ist,  wie  die  Breite  sammtlicher  weisser 
Sectoren  zum  ganzen  Kreisumfang." 

Swan,  apparently  working  in  ignorance  of  the  writings  of  Talbot  and  Plateau, 
in  substance  formulates  the  law  anew  in  1849  (see  W.  Swan,  'On  the  Gradual  Produc- 
tion of  Luminous  Impressions  on  the  Eye  and  Other  Phenomena  of  Vision,'  Trans. 
Roy.  Soc.  Edinb.,  1849,  16,  pp.  581-603.  See  also  F.  Boas,  'Ein  Beweis  des  Talbot'- 
schen  Satzes  und  Bemerkungen  zu  einigen  aus  demselben  gezegonen  Folgerungen/ 
Wiedem.  Ann.,  1882,  16,  359-362;  A.  M.  Bloch,  *  Experiences  sur  la  vision,'  Compt. 
Rend,  de  la  Soc.  de  Biol,  1885,  2,  p.  495;  A.  Charpentier,  'Loi  de  Bloch  relative  aux 
lumieres  de  courte  duree,'  ibid.,  1887  4,  p.  5;  etc. 

For  a  more  modern  statement  of  this  law  and  one  also  more  consistent  with  the 
relation  of  changes  in  light  energy  to  changes  in  sensation,  see  Helmholtz,  'Handbuch 
der  physiol.  Optik,'  zw.  Aufl.,  1896,  p.  483,  "Wenn  eine  Stelle  der  Netzhaut  von 
periodisch  veranderlichem  und  regelmassig  in  derselben  Weise  wiederkehrendem  Lichte 
getroffen  wird,  und  die  Dauer  der  Periode  hinreichend  kurz  ist,  so  entseht  ein  continuir- 
hcher  Eindruck,  der  dem  gleich  ist,  welcher  entstehen  wiirde,  wenn  das  wahrend  einer 
jeden  Periode  eintreffende  Licht  gleichmassig  uber  die  ganze  Dauer  der  Periode 
vertheilt  wiirde";  or  E.  C.  Sanford,  'Experimental  Psychology,'  1898,  p.  146,  "When 
once  the  rate  of  rotation  is  sufficient  to  give  a  uniform  sensation,  the  color  and  bright- 
ness of  any  concentric  ring  are  the  same  that  they  would  be  if  all  the  light  reflected 


FLICKER  PHOTOMETRY 

sensation  is  the  same  as  is  gotten  by  reducing  the  intensity  of 
each  light  by  an.  amount  proportional  to  the  ratio  of  the 
exposure  time  of  that  light  to  the  total  time  of  exposure  to 
both  lights;  or  in  case  the  photometer  head  is  a  sectored  disc, 
in  proportion  to  the  value  of  the  given  sector  or  set  of  sectors 
to  360°.  That  is,  with  a  total  value  of  each  sector  or  set 
of  sectors  of  180°,  the  effect  on  sensation  is  the  same  as  if  each 
light  were  reduced  one-half  in  intensity;  if  the  total  value  of 
one  sector  or  set  of  sectors  is  90°,  the  effect  on  sensation  is  the 
the  same  as  if  the  light  illuminating  that  sector  were  reduced 
to  one-fourth  of  its  intensity;  if  the  total  value  were  45°,  the 
same  effect  is  produced  as  if  the  light  were  reduced  to  one- 
eighth  of  its  intensity;  etc.  Thus,  even  if  the  rate  of  suc- 
cession that  is  used  in  the  method  of  flicker  could  be  con- 
sidered as  the  fusion  rate  for  the  brightness  component  of  the 
sensation  aroused,  little  advantage  could  be  gained  for  the 
position  in  question.  For  the  conclusion  most  certainly  could 
not  be  avoided  that  the  effect  on  sensation  would  be  the  same 
as  if  the  lights  were  reduced  in  intensity,  and  by  an  amount 
proportional  to  the  ratio  of  exposure  time  of  each  light  to 
the  total  time  of  exposure  to  both  lights. 

The  position  under  discussion  seems  also  to  involve  to 
some  extent  a  confusion  of  principle  of  the  method  of  flicker 
with  the  method  of  critical  frequency.  For  example,  in  the 
method  of  critical  frequency,  the  impressions  are  given  to  the 
eye  at  the  fusion  rate.  We  need  scarcely  call  to  mind  the 
procedure.  One  sector  or  set  of  sectors  of  the  disc  is  illu- 
minated by  one  of  the  lights  to  be  compared  and  the  other  is 
black  or  of  a  very  low  luminosity.  The  disc  is  rotated  at  a 
rate  which  completely  fuses  the  sectors  in  sensation.  This 
light  is  then  removed  and  the  other  light  to  be  compared  is 
substituted  for  it.  The  distance  of  this  light  from  the  disc 
is  then  adjusted  until  the  rate  of  rotation  required  to  produce 
fusion  is  the  same  as  it  was  in  the  previous  case.  When  this 
adjustment  is  obtained  the  intensity  of  illumination  of  the 
disc  by  the  two  lights  is  said  to  have  been  the  same,  and  the 

from  it  were  evenly  distributed  over  its  surface,  and  no  further  increase  in  rapidity 
produced  any  effect  on  its  appearance." 


160  C.  E.  FERREE  AND  GERTRUDE  RAND 

relative  brightnesses  of  the  lights  themselves  are  calculated 
by  the  law  of  inverse  squares.  The  situation  is,  however, 
quite  different  for  the  method  of  flicker.  Both  sectors  or 
sets  of  sectors  of  the  disc  are  illuminated  by  the  lights  to  be 
compared,  and  the  rate  of  rotation  is  to  be  made  such  that 
if  there  were  any  brightness  difference  between  the  sectors, 
the  maximum  of  flicker,  not  fusion,  would  be  produced.  If  a 
rate  were  used  that  would  produce  fusion,  for  example,  for 
any  given  amount  of  brightness  difference,  it  is  obvious  that 
no  difference  in  brightness  equal  to  or  less  than  this  amount 
could  be  detected  by  the  method.  That  is,  the  whole  point 
of  the  method  is  to  use  a  rate  of  speed  that  could  not  possibly 
be  the  fusion  rate  for  any  appreciable  amount  of  brightness 
difference  between  the  impressions  to  be  compared;  and  in  so 
far  as  this  purpose  can  be  realized  in  the  different  cases  in 
which  the  method  is  employed,  sensitivity  for  the  method  is 
obtained. 

What  our  critic  really  needs  to  establish  in  order  to  support 
his  position  is  that  summation  instead  of  fusion  takes  place. 
That  is,  if  the  total  effect  of  each  light  on  sensation  is  to  rise 
to  a  higher  level  than  is  given  by  each  individual  impression, 
the  individual  impressions  must  in  proportion  to  the  rise 
summate  or  add  their  individual  intensities.  To  produce  this 
effect  of  summation,  each  individual  impression  would  have 
to  last  over  in  sensation  until  the  next  impression  of  its  kind 
is  received,  which,  since  the  impressions  alternate,  could  be 
the  next  impression  but  one.  For  example,  when  red  and 
green  lights  are  being  compared,  if  the  value  of  the  red  sensa- 
tion is  to  rise  to  a  higher  level  than  that  given  by  a  single 
impression,  the  sensation  aroused  by  one  exposure  to  red 
would  have  to  last  over  until  sensation  is  aroused  by  the  next 
exposure  to  red;  that  is,  would  have  to  last  through  the  inter- 
val of  exposure  to  green  and  into  and  wholly  or  partly  through 
the  succeeding  interval  of  exposure  to  red.  How  highly 
improbable  it  is  that  this  could  happen  to  any  degree  that 
would  be  of  saving  consequence  to  the  method,  is  shown  by  the 
following  two  considerations,  (a)  The  wavering  character  of 
the  sensation  which  we  call  flicker  is  due  to  the  fact  that  a 


FLICKER  PHOTOMETRY  161 

given  sensation  does  not  carry  over  without  a  great  loss  of 
intensity  through  the  next  succeeding  interval,  let  alone  through 
the  next  interval  but  one.  And  (b)  even  at  the  rate  at  which 
complete  color  and  brightness  fusion  takes  place,  there  is 
according  to  the  Talbot-Plateau  law  no  effect  of  summation 
great  enough  to  cause  each  individual  sensation  to  attain  to  a 
higher  intensity  than  that  fixed  by  the  ratio  of  the  time  of 
exposure  of  its  stimulus  light  to  the  total  time  of  exposure  of 
both  lights,  nor  to  produce  a  noticeable  change  in  this  inten- 
sity, however  great  is  the  speed  of  the  succession.  That  is, 
we  have  a  reduction  of  the  intensity  of  the  sensation  aroused 
by  each  light  which  is  the  same  as  would  be  "gotten  were  the 
intensity  of  each  light  to  be  reduced  by  an  amount  propor- 
tional to  the  ratio  of  the  time  of  exposure  of  that  light  to  the 
total  time  of  exposure  of  both  lights,  and  no  further  increase 
in  the  rapidity  of  the  succession  produces  any  change  in  this 
effect.1 

With  regard  to  the  method  of  flicker,  then,  the  case 
apparently  stands  as  follows.  The  individual  impressions 
are  so  short  that  the  eye  is  very  much  underexposed  to  its 
stimulus,  and  the  rate  of  succession  is  so  slow  that  there  is 

1  If  one  were  permitted  to  interpret  the  Talbot-Plateau  law  with  regard  to  what 
takes  place  when  a  rate  of  succession  is  employed  greater  than  the  fusion  rate  for  both 
the  colored  and  brightness  components  of  sensation,  two  possibilities  would  be  opened 
for  explaining  why  no  change  in  sensation  is  produced  as  the  rate  of  succession  is 
increased,  and  the  length  of  each  individual  exposure  is  correspondingly  decreased, 
(i)  Either  the  increase  in  the  reduction  of  the  exposure-time  causes  no  further  reduction 
in  the  sensation  aroused  by  the  individual  exposures;  or  (2)  there  is,  owing  to  the 
increased  rate  of  succession,  a  summation  effect  which  just  compensates  for  the  reduc- 
tion of  the  individual  impressions.  Now  even  if  we  were  to  accept  as  true  the  one  of 
these  alternatives  which  is  the  more  favorable  for  the  case  of  flicker,  namely,  that  a 
compensating  summation  action  takes  place,  and  assume  that  this  compensating 
summation  obtains  clear  down  to  the  rate  of  succession  that  is  used  in  the  method  of 
flicker,  we  would  have  to  expect  as  much  reduction  in  the  sensation  aroused  by  each 
of  the  lights  as  is  expressed  by  the  Talbot-Plateau  law.  That  is,  the  reduction  for 
each  would  be  the  same  as  would  be  gotten  were  the  intensity  of  each  light  to  be  re- 
duced in  proportion  to  the  exposure-time  of  each  to  the  exposure-time  of  both.  As  we 
have  already  pointed  out,  however,  it  is  extremely  improbable  that  there  could  be  a 
compensating  summation  action  at  the  flicker  rate  great  enough  to  be  of  any  consid- 
erable consequence  to  the  method,  because  the  wavering  character  of  the  sensation 
which  we  call  flicker  is  due  to  the  fact  that  a  given  sensation  does  not  carry  over 
without  great  loss  until  the  next  one  develops,  let  alone  until  the  next  but  one 
develops,  which  it  would  have  to  do  to  produce  any  summation  effect. 


1 62  C.  E.  FERREE  AND  GERTRUDE' RAND 

not  enough  carrying-over  from  impression  to  impression  to 
produce  fusion,  let  alone  the  summation  effect  which  is 
needed  to  cause  the  intensity  of  the  sensation  to  rise  to  its  full 
value  or  perhaps  even  to  a  higher  level  than  would  be  given 
by  a  single  exposure.  Moreover,  according  to  the  Talbot- 
Plateau  law  a  summation  effect  great  enough  to  cause  the  sen- 
sation to  rise  to  its  full  value  is  never  produced,  however  fast 
is  the  rate  of  succession;  for  once  the  fusion  rate  is  obtained, 
there  is  a  reduction  of  the  intensity  of  the  sensation  aroused  by 
each  light  which  is  the  same  as  would  be  gotten  were  the 
intensity  of  each  light  to  be  reduced  in  proportion  to  the 
time  of  exposure  of  that  light  to  the  total  time  of  exposure 
to  both  lights,  and  there  is  no  change  in  this  effect  however 
much  the  rate  of  succession  is  increased. 

1  Since  the  above  discussion  was  presented  to  the  Illuminating  Engineering 
Society,  Ives  in  collaboration  with  Kingsbuiy,  has  published  a  sixth  article  on  the 
method  of  flicker  (Philos.  Mag.,  Nov.,  1914,  28  (167),  pp.  708-728)  in  which  a  theory 
of  flicker  photometry  is  developed  based  on  an  analogy  drawn  between  the  response 
of  the  eye  under  successive  stimulation  to  the  action  of  incandescent  lamp  filaments 
under  a  fluctuating  current.  The  gist  of  the  article  is  that  if  the  eye  behaves  under 
the  conditions  obtaining  in  flicker  photometry  as  do  lamp  filaments  (subject  to  cer- 
tain modifications  which  are  not  in  accordance  with  what  is  known  of  the  function- 
ing of  the  eye)  under  a  fluctuating  current,  the  method  of  flicker  should  give  with 
high  intensities  of  light  at  the  photometer  screen  the  same  results  on  the  average  as 
the  equality  of  brightness  method.  It  is  our  purpose  here  merely  to  note  the  article, 
not  to  give  a  detailed  discussion.  The  theory  will  be  discussed  in  a  later  paper  in  con- 
nection with  further  experimental  data.  It  may  not  be  out  of  place  to  state  at  this 
time,  however,  that  the  analogy  of  the  eye  and  the  incandescent  lamp  filament  is  not 
based  on  experimental  examination  of  the  eye's  manner  of  response,  but  is  assumed. 
Moreover,  considerable  evidence  is  offered  in  the  present  paper,  we  think  that  the 
eye  does  not  react  to  its  stimulus  given  to  it  in  succession  at  the  flicker  rate  according 
to  the  laws  which  govern  the  temperature  response  of  lamp  filaments,  more  especially 
when  the  impressions  differ  widely  as  to  wave-length.  It  has  not  been  claimed,  for 
example,  that  the  flicker  method  does  not  give  the  same  results  as  the  equality  of 
brightness  method  when  the  lights  compared  do  not  differ  as  to  wave-length. 


DISCUSSION 
THE    FUNCTION   OF    INCIPIENT    MOTOR    PROCESSES1 

There  is  no  doubt  that  such  a  theory  as  the  author  discusses  is 
of  important  advantage,  yielding  a  base  for  a  fair  understanding 
of  nervous  functions.  In  regard  to  the  assumption  that  the  dis- 
charge of  a  motor  center  may  induce  the  discharge  of  a  cortical 
center  that  is  tributary  to  it,  there  is  evidently  something  left  to 
the  imagination  of  the  reader.  It  is  possible  that  from  the  point 
of  view  of  practical  or  quantitative  science,  so  to  speak,  some  other 
hypothesis  may  be  found  more  defensible. 

With  this  in  mind  the  writer  will  venture  to  describe  the  nervous 
mechanisms  that  produce  the  image,  holding  to  the  author's  first 
assumptions  but  departing  from  the  induced  discharge  assumption. 
To  bring  out  the  point  quickly,  let  us  begin  by  considering  the 
following  case  that  is  easy  of  explanation,  and  lead  up  gradually 
to  the  functions  under  controversy. 

If  a  child  sees  a  red  ball  and  utters  the  word  ball,  and  then 
makes  a  forward  movement,  certain  associations  will  be  formed. 
At  a  later  time  the  child  is  prompted  to  utter  the  word  ball  but 
the  movement  is  only  partially  carried  out  and  the  word  is  inaudible. 
An  image  of  the  red  ball  appears  in  the  child's  mind.  Now  in  the 
first  occurrence  which  we  may  term  the  experience,  we  may  say 
that  there  are  afferent  impulses  due  to  the  sight  of  red,  to  the  shape 
of  the  ball  and  to  the  sound  of  the  uttered  word.  These  go  to  the 
cortex,  or  at  least  a  part  of  each  kind  does  so.  There  are  also 
kinsesthetic  impulses  from  the  eye  muscles  and  from  the  throat 
and  lips,  and  a  part  of  these  causes  excitation  in  the  cortex. 

In  the  second  occurrence,  which  we  may  term  the  recall,  there 
are  kinaesthetic  impulses  from  the  muscles  used  for  the  word  and 
no  doubt  some  of  these  will  be  just  the  same  as  if  the  word  had  not 
been  suppressed  but  uttered  aloud.  Now  if  conditions  are  right, 
these  latter  excitations  will  reach  the  cortical  centers  which  were 
excited  in  the  experience.  The  author's  first  assumptions  and 
theory  of  association  are  the  explanation.  Take  the  color  red  for 
example.  In  the  experience,  the  excitation  starts  in  the  retina, 

1 M.  F.  Washburn,  PSYCH.  REV.,  Vol.  XXI.,  No.  5. 

163 


164  S.  BENT  RUSSELL 

thence  goes  to  the  cortical  center  for  red,  thence  it  flows  to  the  motor 
centers  in  activity.  Within  a  moment  the  excitations  from  the 
speech  muscles  pass  through  the  cortex  and  perhaps  follow  the 
identical  neurons  just  stimulated  by  the  color.  By  the  rules, 
the  common  pathway  will  have  its  conductivity  increased  by  the 
experience. 

When  the  recall  comes,  the  flow  from  the  receptors  in  the 
muscles  will  follow  this  line  of  increased  conductivity,  pass  through 
the  cortical  center  for  red  and  hence  an  image  of  red  will  arise. 
The  flow  will  proceed  from  the  cortical  center  by  the  pathways 
that  are  open  to  some  motor  center  or  centers.  Thus  we  see  that 
the  suppressed  utterance  of  the  word  ball  has  brought  up  an  image 
of  the  color  red  and  yet  there  has  been  no  induced  discharge  such 
as  the  author  describes.  For  the  above  demonstration,  it  is  essen- 
tial that  in  the  recall  some  of  the  muscles  be  partially  contracted 
so  as  to  cause  the  kinsesthetic  excitations  which  we  assume  to 
follow  from  muscular  contractions. 

Let  us  now  go  a  step  further  and  suppose  that  some  time  later 
there  is  an  occurrence  we  will  term  the  secondary  recall.  The  child 
is  prompted  to  utter  the  word  but  there  is  no  movement  and  no 
real  contraction  nor  even  a  noticeable  change  of  tone  in  any  muscle. 
Again  an  image  of  the  red  ball  appears.  It  is  probably  fainter  than 
in  the  previous  case  but  it  is  still  clear. 

To  explain  the  secondary  recall,  we  will  advance  the  theory  of 
strain  signals. 

Beginning  with  the  motor  discharge  which  prompts  the  utter- 
ance but  is  not  of  sufficient  intensity  to  cause  muscular  contraction, 
we  are  brought  to  the  motor  terminal  in  the  muscle.  Let  us  here 
make  the  following  assumption: 

When  a  nervous  discharge  to  a  motor  terminal  is  too  weak  to 
cause  contraction  it  will  produce  a  chemical  or  molecular  change  in 
the  muscle  substance  which  spreads  to  the  sensory  terminals, 
causing  an  excitation  of  certain  neurons,  which  we  will  term  a 
strain  signal.  This  change  in  the  muscle  substance  requires  about 
the  same  time  as  a  muscular  contraction. 

With  the  aid  of  this  assumption  our  explanation  of  the  secondary 
recall  will  follow  the  same  course  as  for  the  other  recall.  The  strain 
signal  acts  upon  the  cortex  just  as  a  kinsesthetic  excitation  would 
and  stimulates  those  very  sensitive  cortical  neurons  which  give 
rise  to  the  image.  Thus  we  see  again  that  the  incipient  utterance 
of  the  word  ball  has  brought  up  an  image  of  the  color  red.  It  is 


MOTOR  PROCESSES  165 

worth  noting  that  between  the  two  types  of  recall  that  we  have 
discussed,  there  are  possible  stages  where  kinaesthetic  impulses  from 
some  muscles  are  joined  by  strain  signals  from  others  to  arouse  the 
image. 

We  find  that  the  theory  of  strain  signals  is  in  some  conformity 
with  the  good  old  rule  that  what  is  true  approaching  a  limit  is  true 
at  the  limit,  for  the  image  arises  from  a  discharge  coming  from  the 
muscle  to  the  cortex,  both  when  there  is  some  contraction  occurring 
and  when  the  contraction  is  incipient  only.  Moreover  the  theory 
appears  to  be  borne  out  by  introspection  as  when  you  recall  a 
song,  the  words  seem  to  sound  in  your  ears  at  about  the  same  rate 
of  succession  as  if  you  were  singing  them.  Again,  the  intimate 
relation  of  nerve  to  muscle  would  indicate  that  a  disturbance  of 
the  motor  nerve,  however  faint,  would  cause  a  change  of  some  kind 
in  the  muscle  as  the  theory  requires.  It  may  be  only  a  sort  of 
ripple  like  a  sound  wave  that  traverses  the  muscle.  If  the  reader 
has  given  much  thought  to  such  matters,  he  will  be  able  to  find 
other  arguments  in  favor  of  the  theory  of  strain  signals. 

It  would  take  too  long  to  discuss  fairly  the  matter  of  "imageless" 
conscious  processes  or  degrees  of  clearness  or  faintness  of  images. 
We  may  briefly  note,  however,  that  in  considering  these  matters, 
one  should  keep  in  mind  the  rules  for  the  formation  of  associations 
and  the  changes  that  occur  during  the  development  of  a  movement 
system  or  performance.  As  the  performance  is  being  perfected  by 
practice,  unnecessary  movements  are  dropped.  But  the  dropping 
of  movements  means  the  elimination  of  kinaesthetic  impulses  and 
also  certain  changes  in  the  excitations  due  to  the  reaction  of  the 
environment.  These  eliminations  and  changes  will  naturally  result 
in  the  fading  and  disappearance  of  images  and  in  the  formations 
of  new  associations.  By  way  of  illustration,  remember  that  the 
images  of  Tuesday  reflect  the  movements  of  Monday  and  prevail 
over  the  faded  images  that  reflect  the  movements  of  Sunday. 
In  the  final  stage  when  the  performance  has  become  automatic, 
the  only  paths  of  high  conductivity  will  be  those  connecting  the 
movements  or  essential  to  the  performance. 

Finally  it  is  submitted  that  the  considerations  brought  out  by 
the  author  regarding  attention  would  be  met  by  the  theory  of 
strain  signals  equally  well  as  by  the  author's  theory  of  incipient 
motor  processes  involving  induced  discharge. 

Comparing  the  two  theories,  we  observe  that  the  author's 
theory  assumes  that  a  motor  discharge  that  is  too  faint  to  cause 


1 66  5.  BENT  RUSSELL 

contraction  of  the  muscle  is  strong  enough  to  induce  a  discharge  in 
the  extremely  sensitive  tributary  cortical  center.  The  theory  of 
strain  signals  assumes  that  a  motor  discharge  that  is  too  faint  to 
cause  contraction  is  strong  enough  to  excite  certain  sensory  terminals 
in  the  muscle  which  have  communication  with  cortical  centers. 

S.  BENT  RUSSELL 


VOL.  XXII.  No.  3  May,  1915 


THE  PSYCHOLOGICAL  REVIEW 


THE  THEORY  AND  PRACTISE  OF  THE  ARTIFICIAL 

PUPIL 

BY  LEONARD  T.  TROLAND 

Harvard  University,  Cambridge,  Mass. 

So  far  as  the  writer  can  ascertain  the  references  in  the 
literature  to  the  theory  and  application  of  artificial  pupils, 
although  not  infrequent,  are  quite  unenlightening.  Yet  in 
all  work  upon  the  visual  processes  in  which  the  amount  of 
light  energy  striking  the  retina  has  to  be  controlled  the 
artificial  pupil  would  seem  to  be  an  indispensable  accessory. 
Its  value  in  exact  studies  upon  visual  acuity  is  also  self- 
evident. 

The  intensity  of  the  light  which  strikes  the  retina  at  any 
time  is  determined  not  only  by  the  intensity  and  distance 
of  the  source,  but  also  by  the  size  of  the  pupil.  It  is  useless 
to  experiment  upon  the  effects  of  lights  of  different  objective 
intensities  upon  the  retina  if  the  reaction  of  the  pupil  to  these 
lights  is  disregarded,  for  as  soon  as  the  objective  intensity  is 
increased  the  pupil  contracts,  and  vice  versa,  so  that  there  is 
a  tendency  for  the  retina  to  receive  a  constant  illumination, 
independent  of  changes  in  the  intensity  and  distance  of  the 
stimulus.  This  tendency  fails  to  be  effective  only  for  very 
bright  or  for  very  dim  lights,  for  which  the  pupil  has  attained, 
approximately,  its  minimum  or  maximum  opening. 

In  addition  to  the  compensating  effect  just  mentioned 
the  behavior  of  the  natural  pupil  offers  another  difficulty  to 
the  student  of  retinal  physiology  in  the  continued  fluctuations 
in  opening  which  it  exhibits  even  for  a  constant  illumination. 
These  fluctuations  are  periodic  in  character,  but  they  follow 
no  definite  law,  and  the  average  aperture  about  which  they 

167 


1 68  LEONARD  T.  TROLAND 

hover  varies  for  different  persons  and  for  the  same  person  at 
different  times.  Such  variations  are  sufficient  to  render 
impossible  accurate  comparative  tests  of  retinal  sensitivity 
without  the  introduction  of  some  further  artifice. 

A  partial  solution  of  the  difficulty  lies  in  temporarily 
disabling  the  pupillary  reflexes  by  the  use  of.  such  drugs  as 
homatropin  and  pilocarpin.  This  procedure,  however,  is  not 
feasible  in  extensive  researches  on  account  of  the  discomfort 
which  it  entails  for  the  subjects.  Moreover,  it  does  not 
insure  the  same  pupillary  opening  for  different  persons,  or 
even,  at  different  times,  for  the  same  person,  so  that  if 
results  are  to  be  made  comparative  the  size  of  the  pupil 
must  be  measured  for  each  series  of  observations. 

The  simplest  and  surest  way  in  which  to  eliminate  the  in- 
fluence of  the  pupil  upon  retinal  measurements  would  seem  to 
be  to  place  in  front  of  the  natural  pupil  a  diaphragm  the 
aperture  of  which  is  smaller  than  the  smallest  aperture  of  the 
natural  pupil,  and  which  is  concentric  with  the  latter.  It  is 
the  purpose  of  the  present  paper  to  discuss  the  theory  and 
practice  of  such  an  "artificial  pupil." 

The  three  important  problems  which  are  involved  in  the 
use  of  the  artificial  pupil  consist  in  the  determination  of  the 
proper  size  of  the  diaphragm,  of  the  distance  from  the  eye 
at  which  it  must  be  placed,  and  the  invention  of  some  means 
of  insuring  the  coincidence  of  the  axis  passing  through  the 
center  of  the  stimulating  field  and  that  of  the  diaphragm  with 
the  center  of  the  natural  pupil.  The  geometrical  and  optical 
conditions  under  which  the  artificial  pupil  must  be  employed 
make  it  necessary  for  the  stimulus  to  be  distinctly  limited  in 
angular  size,  and  thus  make  impossible  its  application  in  the 
study  of  vision  in  the  extreme  periphery. 

The  necessary  size  of  the  aperture  of  the  artificial  pupil 
depends  upon  four  variables:  (i)  the  diameter  of  the  surface 
used  as  a  stimulus,  (2)  the  distance  of  this  stimulus  from  the 
eve>  (3)  tne  minimal  size  of  the  natural  pupil  under  this 
sort  of  illumination,  and  (4)  the  distance  between  the  artificial 
and  natural  pupils.  The  main  condition  for  the  successful 
use  of  the  artificial  pupil  is  that  it  should  be  so  adjusted  that 


THE  ARTIFICIAL  PUPIL 


169 


none  of  the  light  from  the  stimulus  is  intercepted  by  the 
iris  of  the  eye  itself. 

Although  the  refraction  which  occurs  as  the  light  passes 
through  the  surface  of  the  cornea  narrows  the  pencil  of  rays, 
practical  considerations  nevertheless  demand  that  the  arti- 
ficial pupil  be  smaller  than  the  natural  one  at  any  time.  In 
the  ensuing  discussion  we  shall  neglect  the  effect  of  refraction 
at  the  corneal  surface  since  the  error  which  such  neglect 
introduces  into  our  calculations  merely  contributes  to  the 
large  margin  of  safety  which  is  necessary,  at  all  events  in  the 
use  of  the  artificial  pupil.  The  argument  becomes  more 


rigid,  and  also  more  immediately  applicable  to  practise,  if  for 
o,  below,  the  diameter  of  the  so-called  Eintrittspupille  is  em- 
ployed, in  place  of  the  actual  pupillary  opening,  the  value  of  x 
being  taken  to  correspond.  This  means  using  the  size  and 
distance  of  the  apparent  pupil  rather  than  of  the  actual.  Prac- 
tically, however,  the  difference  between  these  two  cases  may  be 
neglected. 

The  accompanying  diagram,  Fig.  i,  represents  in  cross- 
section  the  arrangement  of  the  artificial  pupil  with  respect 
to  the  natural  pupil  and  the  stimulating  surface,  a  is  the 
diameter  of  the  artificial  pupil,  o  that  of  the  natural  pupil, 
w  that  of  the  stimulus,  d  is  the  distance  from  the  plane  of 


170  LEONARD  T.  TROLAND 

the  stimulus  to  that  of  the  iris,  while  x  is  the  distance  between 
the  iris  and  the  artificial  pupil.  The  lines  AB  and  CD 
represent  those  light  rays  which  form  the  critical  boundaries 
of  the  rays  passing  through  the  artificial  pupil.  (It  may  not 
be  immediately  obvious  why  these  lines  are  the  ones  which 
it  is  important  for  us  to  consider,  rather  than  the  external 
boundaries  of  the  whole  pencil  of  rays,  but  a  study  of  the 
diagram  will  make  this  clear.)  The  point  of  intersection,  E, 
of  the  lines  in  question  has  critical  significance,  and  may  be 
called  the  crossing-point,  the  distance  of  this  point  from  the 
plane  of  the  natural  pupil  being  /. 

Inspection  of  the  diagram  shows  the  following  relations 
to  be  true: 


w  -r;-       • 

If  we  solve  for  /  in  (i),  and  for  a  in  (2),  and  then  eliminate  /, 
we  get: 

o(d  —  x)  —  wx 


(3) 


d 


which  gives  us  the  maximum  diameter  of  the  artificial  pupil 
which  will  satisfy  the  prescribed  conditions. 

On  account  of  the  relative  convergence  of  the  pencil  of 
rays  after  it  has  passed  through  the  cornea  the  diameter 
calculated  by  the  above  formula  would  not,  strictly  speaking, 
be  the  largest  available  opening.  However,  in  practise  it 
would  be  very  unsafe  to  utilize  an  opening  closer  to  the  maxi- 
mum. There  are  two  reasons  for  this:  first,  the  fact  that 
slight  accidental  movements  of  the  eye  and  head  are  un- 
avoidable, even  with  the  best  of  head-rests  and  fixation,  and, 
second,  the  fact  that  the  natural  pupil  is  subject  to  constant 
fluctuations  in  size.  Ordinarily  it  is  advisable  to  work  with 
an  opening  at  least  two  millimeters  smaller  than  the  maximum 
for  the  smallest  aperture  of  the  natural  pupil  which  is  to  be 
expected  in  the  course  of  the  observations. 


THE  ARTIFICIAL  PUPIL 


The  distance,  /,  of  the  crossing-point  from  the  plane  of  the 
iris  may  be  calculated  from  the  formula: 


which  follows  from  (i),  above.  The  position  of  this  point 
depends  upon  the  size  and  distance  of  the  stimulus  and  upon 
the  aperture  of  the  natural  pupil.  A  knowledge  of  it  is 
important,  since  if  the  artificial  pupil  is  placed  in  front  of 
the  crossing-point  it  will  necessarily  fail  in  its  purpose,  no 
matter  how  small  it  is  made.  The  distance  of  this  point 
from  the  eye  is,  in  general,  of  sufficient  magnitude  so  that 
the  artificial  pupil  may  be  placed  in  a  position  comfortable 
to  the  observer.  For  example,  when  the  diameter  of  the 
stimulus  is  5  centimeters,  its  distance  I  meter,  and  the  natural 
pupil  3  millimeters,  /  is  approximately  6  centimeters. 

To  determine  the  maximum  admissible  diameter  of  the 
stimulus  under  given  conditions,  the  original  equations  may 
be  solved  for  zv,  with  the  result: 

,  N  d(o  —  a)  —  ox 

(5)  m  =  -s  -  -f  -  . 

•V 

With,  for  example,  a  pupil  aperture  of  4  millimeters,  an 
artificial  pupil  of  I  millimeter,  and  the  values  of  x  and  d 
used  in  the  example  above,  we  find  w  to  be  approximately 
30  centimeters.  The  corresponding  angular  aperture  is  17°. 
It  is  clear  that  if  we  wish  to  increase  the  angular  size  of  the 
stimulus  we  must  decrease  a  or  x  or  both.  The  limit  for  x 
is  the  distance  from  the  iris  to  the  cornea,  viz.,  a  little  under 
4  millimeters,  that  of  a  is  zero.  Substituting  these  values  in 
place  of  those  first  employed  we  get:  w  =  (approximately) 
I  meter.  This  corresponds  to  an  angular  opening  of  about 
53°.  It  would  appear  to  be  the  maximal  size  of  stimulus  in 
connection  with  which  the  artificial  pupil  can  be  used  under 
ordinary  conditions. 

Evidently,  however,  this  maximum  is  of  such  a  character 
as  to  make  the  artificial  pupil  available  in  the  study  of  all  of 
the  color  perceptive  regions  of  the  retina,  since  these  do  not 
extend,  in  general,  beyond  50°.  In  practise,  of  course,  it 


172  LEONARD  T.  TROLAND 

would  be  necessary  for  the  pupil  to  have  a  finite  aperture 
and  to  be  removed  from  the  cornea  by  a  distance  somewhat 
greater  than  that  allowed  in  the  above  calculation  (viz. 
.5  mm.). 

The  best  possible  conditions  for  the  use  of  the  artificial 
pupil  would  be  those  which  go  with  complete  mydriasis. 
Under  these  conditions  the  aperture  of  the  natural  pupil  is 
about  7.5  millimeters.  With  an  artificial  pupil  of  I  millimeter 
aperture,  and  a  distance  from  the  iris  of  8  millimeters,  the 
angular  size  of  the  largest  available  stimulus  would  be  about 
46°.  The  worst  possible  conditions  are  those  of  complete 
miosis,  which  give  a  natural  pupil  of  about  1.5  millimeters. 
The  maximum  angular  size  of  the  stimulus  for  the  latter 
conditions  is  approximately  11.5°.  These  maxima  include 
the  margin  of  safety,  introduced  by  corneal  refraction,  which 
was  mentioned  at  the  outset.  In  general,  of  course,  the 
artificial  pupil  would  not  be  used  in  connection  with  the  drugs 
which  are  customarily  employed  to  produce  mydriasis  and 
miosis,  and  consequently  it  is  necessary  to  base  one's  calcula- 
tions upon  the  so-called  physiological  pupil,  which  lies 
between  3  and  4  millimeters  for  a  considerable  range  of 
intensities  of  the  stimulus. 

The  final,  and  perhaps  the  most  difficult  problem  which 
must  be  solved  in  the  use  of  the  artificial  pupil  is  that  of 
securing  what  may  be  called  register  between  the  natural 
and  the  artificial  diaphragms.  Perfect  registration  may  be 
defined  as  a  disposition  of  the  eye  with  reference  to  the 
artificial  pupil  such  that  the  axis  passing  through  the  centers 
of  the  stimulus  field  and  the  artificial  pupil,  and  perpendicular 
to  the  planes  of  these,  also  passes  through  the  center  of  the 
natural  pupil,  and  is  perpendicular  to  the  plane  of  the  iris. 
Under  these  conditions  the  projection  of  the  natural  pupil 
on  the  plane  of  the  artificial  pupil  is  concentric  with  the 
latter. 

The  conditions  accompanying  the  use  of  the  artificial 
pupil  are  such  as  to  make  it  difficult,  if  not  impossible,  to 
secure  or  test  registration  by  objective  observations.  Ap- 
proximate registration  can  be  obtained  by  moving  the  head 


THE  ARTIFICIAL  PUPIL  173 

slightly  with  the  eye  in  position,  since  when  the  artificial 
and  natural  pupils  do  not  coincide  the  intensity  of  the 
stimulus  appears  to  be  reduced.  However,  in  most  work  in 
which  the  artificial  pupil  is  helpful  it  is  desirable  that  registra- 
tion should  be  secured  before  the  eye  is  exposed  to  the  action 
of  the  stimulus. 

One  method  of  securing  accurate  registration  would  be 
to  place  two  dimly  illuminated  diaphragms  concentrically  on 
the  axis  passing  perpendicularly  through  the  center  of  the 
stimulus  field,  these  diaphragms  to  be  at  different  distances 
from  the  latter  and  of  such  size  that,  when  the  eye  is  in 
position,  the  edge  of  the  farther  one  can  be  seen  framed  in 
that  of  the  nearer.  If  the  artificial  pupil  now  be  placed 
concentric  with  the  diaphragms  the  eye  will  be  in  register 
when  the  framing  of  the  one  diaphragm  in  the  other  appears 
concentric. 

A  neater  and  somewhat  simpler  method  of  insuring 
registration — the  one  now  in  use  by  the  author — is  the 
following: 

It  is  a  well-known  fact  that  if  a  small  source  of  light  be 
held  very  close  to  the  eye  it  will  be  seen  not  in  its  true  form, 
but  as  a  relatively  large  "  diffusion  circle,"1  fluctuating  in  size 
with  the  constant  changes  which  are  occurring  in  the  size  of 
the  pupil.  Such  a  circle  is  in  reality  a  luminous  shadow  of 
the  natural  pupil,  and  if  the  point  of  light  be  on  the  line  of 
sight  the  diffusion  circle  which  it  produces  will  be  concentric 
with  the  fovea,  provided,  of  course,  that  the  pupil  itself  is  not 
eccentric.  If,  now,  a  true  circle  be  placed  concentric  with 
the  same  axis,  but  at  a  greater  distance,  so  that  a  more  or 
less  distinct  image  of  it  can  be  formed  on  the  retina,  this 
image  will  be  seen  to  be  concentric  with  the  diffusion  circle, 
but  if  it  is  displaced  it  will  become  eccentric  with  respect  to 
the  latter. 

If  an  adequately  small  artificial  pupil  be  placed  in  front  of 
the  eye  and  in  register  with  the  natural  pupil  the  size  of  the 
diffusion  circle  will  be  determined  by  the  former  instead  of 

^n  the  theory  of  the  " Zerstreuungskries"  see:  Helmholtz,  "Handbuch  der 
physiologischen  Optik,"  3d  ed.,  1909,  Vol.  I,  pp.  101-120. 


'74 


LEONARD  T.  TROLAND 


the  latter.  With  perfect  registration  the  Zerstreuungskreis 
in  question  will  be  seen  to  be  concentric  with  the  image  of 
the  second  circle  mentioned  above,  but  when  the  registration 
is  imperfect  the  two  will  be  eccentric  with  respect  to  each 
other.  We  are  thus  provided  with  a  very  accurate  means  of 
securing  and  of  testing  registration. 

Fig.  2  represents,  somewhat  diagrammatically,  an  element 
of  the  artificial  pupil  apparatus  which  the  writer  has  been 
using  in  his  investigations  concerning  retinal  fatigue,  and 


FIG.  2. 

which  embodies  in  a  general  way  the  principle  just  described 
together  with  the  others  previously  discussed.  The  pupillary 
diaphragm,  P,  is  held  at  the  end  of  a  small  telescoping  tube 
before  the  other  end  of  which  a  small  electric  light,  Z,  carrying 
in  front  of  it  a  piece  of  opal  glass,  G,  can  be  let  down  by  the 
movement  of  a  shutter,  S.  When  this  light  is  in  position 
and  the  eye  is  held  opposite  the  artificial  pupil,  the  reflection 
of  the  light  from  the  interior  walls  of  the  tube  near  to  the  eye 


THE  ARTIFICIAL  PUPIL  175 

produces  a  large  diffusion  circle  upon  the  retina.  Within 
this  circle  of  light  is  seen  a  smaller,  dark,  circular  ring  which 
is  constituted  by  the  image  of  the  circular  diaphragm,  D,  at 
the  far  end  of  the  tube.  When  these  two  circles  are  seen  to 
be  concentric  the  line  of  vision  must  coincide  with  the  axis 
of  the  artificial  pupil  and  the  diaphragm  in  question.  The 
conditions  described  are  those  of  approximate  registration. 
In  practise,  registration  is  secured  by  a  brief  exposure  of  the 
eye  of  the  subject  to  the  test  light — which  can  and  should 
be  very  dim — during  which  exposure  he  adjusts  his  head  so 
that  the  two  circles  are  seen  as  concentric,  fixation  being 
directed  to  the  center  of  the  inner  one.  The  head  is  then 
held  firmly  in  position,  the  test  lamp  is  extinguished,  and  the 
eye  is  given  a  period  of  rest  sufficient  to  remove  the  effects 
of  the  faint  stimulation  which  it  has  thus  received.  When 
the  absence  of  such  effects  is  insured  the  shutter  is  raised 
and  the  stimulus  proper  is  exposed.  When  the  observation 
is  completed  the  shutter  is  again  dropped,  the  test  lamp 
lighted,  and  the  state  of  concentricity  or  eccentricity  of  the 
circles  is  again  noted.  The  author  has  found  that  his  sub- 
jects have  little  difficulty  in  maintaining  practically  perfect 
registration  in  this  way  during  periods  of  several  minutes' 
duration,  a  simple  head  and  chin  rest  being  employed. 

The  diaphragm,  Z),  acts  to  prevent  the  relatively  small 
stimulus  field  from  illuminating  the  walls  of  the  tube,  al- 
though it  does  not  interfere  with  such  illumination  by  the 
registration  lamp.  The  interior  of  the  tube  should,  of  course, 
be  painted  black,  and  the  current  supplied  to  the  lamp  should 
pass  through  an  adjustable  resistance  so  that  the  intensity 
of  the  light  may  be  easily  reduced  to  a  minimum.  The 
apparatus  as  figured  is  not  applicable  to  maximally  large 
stimulus  fields. 

Neither  of  the  two  methods  described  above  can  be 
relied  upon  to  give  perfect  registration  unless  a  possible 
anatomical  eccentricity  of  the  natural  pupil  is  taken  into 
consideration.  According  to  Gullstrand,1  such  eccentricity 
is  the  rule  rather  than  the  exception.  Usually,  however, 

1  A.  Gullstrand,  Appendix  to  Helmholtz's  "  Handbuch  der  physiologischen 
Optik,"  3d  ed.,  Vol.  i,  1909,  pp.  270-272. 


176  LEONARD  T.  TROLAND 

the  lack  of  concentricity  is  not  marked,  so  that  if  the  artificial 
pupil  employed  is  relatively  small — say  one  half  the  diameter 
of  the  natural  pupil — registration  of  the  line  of  sight,  which  is 
obtained  by  the  methods  in  question,  may  be  relied  upon  for 
practical  purposes. 

In  careful  work,  however,  the  pupils  of  the  subjects  should 
be  measured  to  determine  their  eccentricity.  Registration 
may  then  be  effected  by  having  each  subject  so  place  his 
eye  that  the  inner  circle  is  eccentric  with  respect  to  the 
diffusion  spot  in  such  a  direction  and  to  such  a  degree  as  to 
correct  for  the  eccentricity  of  the  pupil. 

One  way  of  testing  the  concentricity  of  the  natural  pupil, 
which  will  at  the  same  time  educate  the  subject  in  the  amount 
of  eccentricity  necessary  to  correct  the  registration  of  each 
eye,  is  the  following.  A  series  of  trials  may  be  made  in  which 
the  stimulus  is  viewed  through  the  artificial  pupil.  Each 
time  the  head  is  adjusted  by  trial  and  error  so  that  the  stimu- 
lus field  appears  as  bright  as  possible,  a  position  being  found 
which  is  as  close  as  may  be  to  the  center  of  the  range  of 
maximum  brightness,  then  this  range  has  an  appreciable 
magnitude.  When  this  position  has  been  secured  the  head 
is  held  rigidly  against  the  head-rest  and  the  registration 
lamp  is  dropped  into  place,  the  degree  of  eccentricity  of  the 
two  circles  being  noted  and  recorded.  The  average  of  a 
number  of  such  determinations  may  be  used  for  correcting 
the  registration. 

The  diffusion-circle  method  of  securing  registration  per- 
mits a  very  simple  qualitative  test  as  to  the  adequacy  of  the 
register  in  a  given  instance,  since  the  outline  of  this  circle  is 
determined  by  the  effective  pupil.  If  the  registration  is 
inadequate,  fluctuations  in  the  outline  of  the  circle  will  be 
apparent,  due  to  the  pulsating  contractions  and  expansions 
of  the  natural  pupil.  The  writer  has  found  that  with  an 
artificial  pupil  of  two  millimeters  (diameter),  using  a  small 
but  bright  stimulus  in  a  dark  room,  registration  of  the  line 
of  sight  is  adequate  for  most  subjects,  although  in  no  subjects 
which  he  has  .examined  has  such  registration  proven  itself 
perfect. 


THE  TEMPORAL  RELATIONS  OF  MEANING  AND 

IMAGERY 

BY  THOMAS  VERNER  MOORE 

Catholic  University  of  America 

I.   THE  PROBLEM 

The  experiments  here  reported  constitute  a  part  of  a  more 
extensive  study  of  memory  and  perception,  which  will  prob- 
ably be  made  public  in  the  future.  The  work  was  done  in 
the  laboratory  of  Professor  Kiilpe  at  Munich.  The  part 
now  published  cannot,  however,  be  properly  evaluated  with- 
out some  indication  of  the  nature  of  the  results  obtained  in 
the  first  section  of  the  more  extensive  study.  This  first  part 
consisted  in  an  introspective  investigation  of  the  mental 
processes  involved  in  perception  and  recall. 

The  material  for  experiment  in  the  unpublished  section 
consisted  of  spoken  words,  printed  words,  printed  pictures 
and  real  objects.  A  series  of  eight  words,  pictures  or  objects 
were  presented  to  the  subjects.  Their  task  was  to  repeat 
what  they  had  seen  or  heard  and  then  to  give  an  introspective 
account  of  the  mental  processes  they  had  experienced  during 
the  perception  of  the  series  and  during  their  attempts  to 
reproduce  the  same  from  memory.1  The  subjects  were  asked 
particularly  to  give  an  account  of  the  temporal  sequence  of 
events  as  they  had  experienced  them. 

It  was  rather  remarkable  that  in  perceiving,  the  first 
thing  in  consciousness  was  reported  as  meaning  the  second 
some  kind  of  imagery.  Whereas  in  repeating  the  first  thing 
was  often  an  image  whose  meaning  was  understood  and  then 
designated  by  a  word. 

A  few  introspections  will  bring  out  more  clearly  what  is 
meant  by  this  assertion. 

1  A  fuller  description  of  the  details  of  the^technique  will  be  given  when  the  entire 
work  is  made  public. 

177 


178  T.  V.  MOORE 

PERCEPTION  OF  PRINTED  WORDS 

"I  notice  now  a  certain  regularity  in  this  process.  With 
the  first  word,  the  meaning  appeared  with  the  reading,  with- 
out any  clear  visual  image  of  the  object  thereby  designated. 
The  same  process  takes  place  on  the  continuation  of  the 
series  of  words.  Gradually  it  goes  on  so  rapidly  that  during 
the  period  of  exposition  (2  seconds)  there  is  time  to  apprehend 
a  goodly  number  of  apperceptive  complexes,  which  become 
associated  with  the  imaged  object.  The  steps  in  the  process 
— so  far  as  I  can  notice  them — are: 

"i.  Apprehension  of  the  meaning. 

"  2.  Imagery  of  the  object — generally  by  means  of  memory 
images. 

"3.  Associations  which  are  connected  with  the  object." 
Subject  Lehner,  Nov.  17.* 

PERCEPTION  OF  PICTURES 

"I  look  at  the  picture  and  generally  have  its  meaning  at 
once.  Often  I  am  not  entirely  certain,  e.  g.,  spoon  or  trowel. 
When  I  have  the  meaning,  its  naming  follows  immediately." 
— Griininger,  Dec.  ly.2 

"In  the  perception  of  the  several  pictures,  I  notice  that  I 
experienced  auditory-motor  words  in  immediate  connection 
with  them,  and  that  these  words  followed  with  varying 
rapidity  the  individual  pictures.  It  lasted  some  time  till  I 
got  the  word  l  Mitre.'  In  this  experience  it  appeared  to  me 
that  the  rapidity  with  which  the  word  comes,  does  not  depend 
as  much  upon  the  finding  of  the  words  as  it  does  upon  the 

1  Ich  merke  jetzt  eine  gewisse  Gesetzmassigkeit  des  Prozesses.     Bei  dem  ersten 
Wort  tritt  mit  dem  Lesen  die  Bedeutung  bewusst  auf,  ohne  deutliches  Gesichtsbild 
des  darin  fixierten  Objektes.     Derselbe  Vorgang  vollzieht  sich  bei  der  Fortsetzung  der 
Reihe,  allmahlich  mit  so  grosser  Schnelligkeit  dass  wahrend  der  Exponierungszeit 
noch  Zeit  bleibt  eine  ganze  Fiille  von  Apperceptionsmassen  bewusst  zu  erfassen,  die 
sich  an  das  vorgestellte  Objekt  noch  kniipfen.     Die  Stufen  so  weit  ich  sie  bemerken 
kann  sind:    i.   Erfassung  der  Bedeutung.     2.   Vorstellung  des  Objektes,  gewohnlich 
durch  Erinnerungsbilder.     3.  Associationen  die  sich  an  das  Objekt  kniipfen.     (lyten. 
Nov.) 

2  Ich  sehe  das  Bild  and  und  meistens  habe  ich  sofort  die  Bedeutung.     Manchmal 
bin  ich  nicht  ganz  sicher  z.  B.  Loffel  oder  Kelle.    Wenn  ich  die  Bedeutung  habe,  folgt 
sofort  die  Benennung. 


MEANING  AND  IMAGERY  i?9 

recognition  of  the  picture.  It  is  on  this  account  that  I  would 
willingly  have  looked  longer  at  the  pictures.  The  words 
served  as  designations  for  the  pictures  or  if  you  will  the 
objects  represented  by  the  pictures,  and  had  another  sense,  a 
more  general  meaning  than  their  relation  to  the  individual 
pictures  or  their  objects." — Subject  Kiilpe,  Nov.  I4.1 

REPETITION  OF  OBJECTS 

"On  repeating,  there  comes  to  me  all  of  a  sudden  a  visual 
image.  When  this  image  comes  promptly  it  is  usually 
complete.  But  when  I  must  think  awhile,  there  comes  to  me 
first  of  all  something  striking  in  the  object.  Then  come 
further  qualities,  e.  g.,  to  the  color  the  form.  As  soon  as  this 
process  of  supplementing  has  developed  to  a  certain  point, 
the  meaning  is  all  of  a  sudden  present.  As  soon  as  I  have 
the  meaning,  the  object  seems  to  become  still  clearer.  E.  g.: 
All  of  a  sudden  I  see  the  typical  lustre  of  a  pearl.  Then 
there  comes  to  me  the  round  form  and  then  all  at  once  I 
know  what  it  is." — Subject  Griininger,  Dec.  io.2 

Were  meaning  in  some  manner  identical  with  imagery, 
or  were  it  produced  by  imagery  or  the  imaginal  context  of  a 
sensation  as  Titchener  suggests  is  often  the  case,  we  should 
expect  just  such  introspections  as  this  from  our  subjects — 
not  however  for  memory  but  for  perception.  That  they  are 

1  Ich  bemerke  dass  ich  bei  der  Wahrnehmung  der'einzelnen  Bilder  sofort  akustisch- 
motorische  Worter  in  Anschluss  an  sie  erlebt  habe,  und  dass  diese  Worter  in  verschie- 
dener  Geschwindigkeit  sich  an  die  einzelnen  Bilder  anschlossen.  Bei  dem  Wort  Bischofs- 
miitze,  z.  B.,  dauerte  es  ziemlich  lang  bis  ich  es  fang.      Dabei  schien  die  Geschwindig- 
keit des  Auftretens  der  Worter  nicht  sowohl  in  der  Wortfi ndung  selbst  als  vielmehr  in  der 
Erkennung  des  Bildes  begriindet  zu  sein.     Damit  hangt  es  zusammen  dass  ich  einige 
Bilder  gerne  langer  betrachtet  hatte.     Die  Worter  galten  als  die  Bezeichnungen  fur 
die  Bilder  bzw.  die  Gegenstande  die  in  ihnen  dargestellt  waren,  und  hatten  einen  an- 
deren  Sinn,  eine  allgemeinere  Bedeutung  als  die  Beziehung  auf  die  einzelnen  Bilder  oder 
ihre  Gegenstande.     (i4ten  Nov.) 

2  Beim  Hersagen  taucht  einfach  ganz  plotzlich  ein  optisches  Bild  auf.     Wenn  das 
Bild  schnell  auftritt,  dann  ist  es  meistens  vollstandig.     Wenn  ich  einige  Zeit  suchen 
muss,  dann  taucht  zuerst  etwas  besonders  auffalliges  am  Gegenstand  auf.     Dann 
kommen  weitere  Qualitaten,  z.  B.  zur  Farbe  die  Form,  und  sobald  diese  Erganzung 
einen  grosseren  Grad  erreicht  hat  ist  die  Bedeutung  auf  einmal  da,  und  sobald  ich  die 
Bedeutung  habe,  scheint  mir  der  Gegenstand  noch  deutlicher  zu  werden.     Z.  B.  Ich 
sehe  auf  einmal  den  eigenartigen  Glanz  der  "  Perle."     Dann  kommt  mir  die  runde  Form, 
und  dann  auf  einmal  weiss  ich  was  es  ist.     (loten  Dez.) 


i8o  T.  V.  MOORE 

found  in  memory  and  not  in  perception  is  strong  evidence 
against  any  such  theory.  Here  the  nature  of  the  occurrence 
points  to  the  fact  that  an  image  as  such  means  nothing  just 
as  Professor  Titchener  himself  claims.  It  must  be  inter- 
preted. It  can  be  interpreted  only  when  sufficient  data  is 
present.  When  this  is  the  case,  the  subject  knows  what  it  is. 
This  knowledge  of  what  the  image  represents  is  not  reported 
as  a  sensory  element  added  to  the  elaboration  of  the  image. 
A  new  image  would  itself  have  to  be  recognized.  The 
interpretation  of  the  image  is  a  knowing.  It  is  something 
which  follows  the  awareness  of  the  image  just  as  understand- 
ing follows  the  sensations  involved  in  perception. 

REPETITION  OF  PICTURES 

"The  repetition  took  place  in  this  manner:  First  I  thought 
of  the  first  member  of  the  series.  Then  without  holding  more 
strictly  to  the  order  of  perception  each  word  was  spoken 
following  an  imaginal  representation  of  the  pictures.  When 
I  stopped,  I  attempted  to  bring  up  to  myself  the  series.  Only 
by  the  rising  up  of  a  visual  image  did  I  obtain  a  new  word." 
—Subject  Kiilpe,  Nov.  I4.1 

Such  introspections  as  these  suggested  a  further  investiga- 
tion. The  subjects  had  noticed  a  certain  sequence  of  events  in 
the  process  of  perception.  Would  it  be  possible  to  react  to 
the  events  that  had  been  noted?  If  meaning  comes  before 
imagery  in  the  perception  of  printed  words,  would  it  be 
possible  for  the  subject  to  react,  now  to  imagery  and  now  to 
meaning?  And  if  so,  what  would  be  the  quantitative  results? 

In  the  experiments  here  reported  this  problem  was  at- 
tempted, to  investigate,  namely,  by  means  of  reaction  time 
the  temporal  relations  of  meaning  and  imagery  in  the  per- 
ception of  printed  words  and  pictures.  The  experiments 
were  made  in  the  psychological  laboratory  of  Professor 

1  Das  Hersagen  geshah  so  dass  ich  mich  zunachst  auf  das  erste  Glied  der  Reihe 
zuriickbesann.  Danach  wurden  die  einzelnen  Worter  im  Anschluss  an  die  anschau- 
lichen  Vorstellungen  der  Bilder  ohne  die  Ordnung  der  Wahrnehmung  strenger  einzu- 
halten  ganannt.  Wenn  ich  stockte,  suchte  ich  mir  die  Reihe  wiederzuvergegen- 
wartigen  und  bekam  erst  durch  eine  neue  Auftauchung  des  Vorstellungsbildes  ein  neues 
Wort  (Nov.  I4th). 


MEANING  AND  IMAGERY  181 

Kiilpe  in  Munich  during  the  winter  semester  of  1913-14 
and  the  summer  semester  of  1914.  The  author  wishes  to 
take  this  opportunity  to  thank  Professor  Kiilpe  for  his  great 
kindness,  for  his  interest  and  suggestions,  and  for  the  sacrifice 
of  his  time  as  subject. 

II.    METHOD  OF  RESEARCH 

The  words  and  pictures  used  in  these  experiments  desig- 
nated simple  familiar  objects — all  capable  of  being  visualized; 
e.  g.,  tree,  lamp,  knife.  Abstract  words,  prepositions,  etc., 
were  not  used,  in  order  that  conditions  might  be  as  favorable 
as  possible  for  the  development  of  imagery.  Had  such  words 
been  used  the  difference  that  was  found  in  reaction  time  for 
meaning  and  imagery  would  have  been  much  greater.  The 
use  of  such  words  would  indeed  have  been  justified.  For  if 
sensations  and  images  must  explain  all  meanings  they  must 
be  involved,  and  exclusively  involved,  not  merely  in  the 
perception  of  things  that  can  be  immediately  sensed,  but  also 
in  more  abstract  mental  content.  In  order,  however,  to  test 
the  theory  on  the  ground  where  it  is  best  able  to  stand,  it 
was  concluded  to  forego  the  use  of  any  words  except  those 
that  represented  familiar  sensory  objects. 

The  accompanying  plates  give  an  insight  into  the  material 
used  in  these  experiments.  Most  of  them  represent  objects 
that  can  be  named  by  a  one  or  two  syllable  German  word. 
The  words  used  were  printed  on  cards  in  a  large  legible  type. 

The  use  of  control  words  and  drawings  enabled  one  to  be 
sure  that  the  subjects  were  actually  reacting  to  meanings. 
The  controls  used  in  the  series  of  words  were  nonsense 
combinations  of  letters  forming  one  or  two  syllables.  The 
controls  used  in  the  series  of  pictures  were  meaningless 
drawings.  In  general,  the  subject  was  instructed  to  react 
(by  releasing  a  telegraph  key)  in  case  the  word  or  the  drawing 
represented  some  real  object.  The  words  were  exposed  by  a 
combination  memory  and  tachistoscope  apparatus.  The  re- 
action times  were  measured  by  a  Hipp  chronoscope.  This 
was  controlled  by  a  pendulum  constructed  in  accordance  with 
a  design  by  Professor  Kiilpe.  The  variable  error  in  the 


182 


T.  V.  MOORE 


MEANING  AND  IMAGERY 


183 


i84 


T.  V.  MOORE 


MEANING  AND  IMAGERY 


1 86 


T.  V.  MOORE 


MEANING  AND  IMAGERY 


187 


1 88 


T.  V.  MOORE 


MEANING  AND  IMAGERY  189 

chronoscope  was  negligible — averaging  less  than  3  cr.  The 
constant  error. was  about  700-.  Nine  subjects  took  part  in 
the  experiments.  A  preparatory  signal  (i->£  sec.)  was  given 
verbally  with  the  aid  of  a  stop  watch. 

III.    SiMPLE1  MEANING  AND  VISUAL  IMAGERY 

(a)  Quantitative  Results 

The  instructions  to  the  subject  in  this  experiment  will 
indicate  the  precise  nature  of  the  problem.  They  are  repro- 
duced without  translation.  The  subject  read  them  over  at 
the  beginning  of  each  period.  A  few  trial  periods  were 
necessary  for  some  subjects  in  order  that  they  might  learn 
not  to  react  to  the  control  word.  These  preparatory  series 
were  not  included  in  the  final  results.  One  of  our  subjects 
(Gl.)  never  did  get  free  from  erroneous  reactions  and  his 
results  show  a  marked  difference  from  the  others. 

Sie  werden  nach  einem  Signal  ein  Wort  zu  sehen  (bzw.zu 
horen)  bekommen.  Ich  bitte  Sie  zu  reagieren  wenn  Sie  das 
Wort  verstanden  oder  seine  Bedeutung  erfasst,  bzw.  wenn 
Sie  eine  Gesichtsvorstellung  von  dem  durch  das  Wort  bezeich- 
neten  Gegenstand  gehabt  haben. 

Die  Worte  ' Bedeutung'  und  'Vorstellung'  werden  Ihnen 
angeben  ob  das  eine  oder  das  andere  verlangt  wird.  Nachher 
bitte  ich  mir  kurz  das  Erlebnis  zu  charakterisieren,  and  dabei 
anzugeben,  ob  die  aufgetauchte  Vorstellung  an  die  Stelle 
der  Bedeutung  gesetzt  werden  konnte,  etwa  bloss  die  konkrete 
anschauliche  Erfullung  dessen  war,  was  in  der  Bedeutung 
abstrakt  intendiert  wurde. 

In  this  series,  therefore,  the  subject  reacted  either  (a)  To 
the  awareness  that  the  word  had  a  meaning,  or  (b)  To  the 
awareness  of  the  visual  image  of  the  object. 

If  there  is  no  difference  between  meaning  and  the  visual 
image  of  an  object  represented  by  a  word  the  average  of  the 
two  series  should  be  approximately  the  same.  The  subject 
ought  not  to  be  able  to  distinguish  meaning  and  imagery 

1  By  'simple  meaning'  is  not  meant  an  absolute  simplicity.  The  word  is  used  to 
contrast  this  set  of  experiments  with  a  later  one  where  the  more  complex  consciousness 
of  purpose  was  required. 


J90 


T.  V.  MOORE 


and  this  should  manifest  itself  in  averages  for  the  two  sets  of 
reactions  that  approached  each  other  within  the  limits  of 
experimental  error.  If  meaning,  however,  is  produced  by 
or  is  identical  with  the  visual  image  which  accrues  to  the 
sensations  involved  in  the  perception  of  the  word,  the  image 
series  should  be  shorter  if  anything  than  the  meaning  series. 
The  results  are  given  below.  The  tables  are  clear  without 
any  explanation,  except  perhaps,  that  in  column  T  is  given  the 

SUBJECT  Gl 
Words 


Date 

Visual  Image        |           T 

v 

Date 

Simple  Meaning 

T 

V 

Zange 

1,182 

628 

Rechen 

368 

154 

23m 

Fernglas 
Pfeil 

563 

233 

9 

321 

23/VI 

Besen 
Gabel 

563 
751 

229 

Messer 

639 

85 

Truthahn 

686 

164 

26m 

Lampe 
Sichel 

640 
660 

86 
106 

26m 

Esel 
Trichter 

676 

550 

154 

28 

Sabel 

472 

82 

Dreick 

602 

80 

7/VII 

Stuhl 
Eimer 

527 
429 

27 
125 

Nest 
Aal 

662 

558 

140 
36 

Baum 

472 

82 

Geige 

338 

184 

A7TT 

Trichter 

346 

208 

Fernglas 

597 

75 

IO/VII 

, 

Korb 

482 

72 

7/VII 

Besen 

424 

98 

12)6,645 

1,831 

Korb 

462 

60 

554 

152 

Maske 

249 

273 

io/VII 

{  Meissel 

171 

15)7,837 

1,887 

Mean    =522 

126 

Median  =  563 

Reactions  to  visual  imagery  equal  or  below  median  =  8. 

SUBJECT  GRUNINGER 
Words 


Date 

Visual  Image 

T 

v 

Date 

Simple  Meaning 

T 

V 

II/II 

Auge 
Ballon 

902 

,092 

341 
151 

II/II 

/  Schuh 
\  Nase 

682 
787 

18 

87 

Kuh 

,660 

4J7 

Fass 

661 

39 

I6/II 

Bohrer 

,277 

34 

I6/II 

Schwan 

659 

41 

Sofa 

,261 

18 

Schaf 

781 

81 

Stiefel 

,229 

H 

[Ring 

531 

169 

25/11 

Schuh 
Fass 

,I03 
1,462 

140 
219 

2SAI 

Auge 
Ballon 

680 
705 

20 
5 

Nase 

1,200 

43 

Fass 

660 

40 

,Kuh 

856 

156 

9)11,186 

i,377 

10)7,002 

656 

1,243 

153 

Mean    =  700 

6<> 

Median  =  68  1 

Reactions  to  visual  imagery  equal  to  or  below  median  =o. 


MEANING  AND  IMAGERY 


191 


SUBJECT  KULPE 
Words 


Date 

Visual  Image 

T 

V 

Date 

Simple  Meaning 

T 

v 

9/n 

{  Lowe 

1,690 

790 

9/n 

Kerze 

517 

H 

13/11 

Ballon 
Auge 

944 
675 

44 

225 

13/11 

Schuh 
Ring 

538 

434 

7 
97 

Rose 

1,097 

197 

Nase 

799 

268 

16/11 

Fliege 
Veilchen 

802 
753 

98 
H7 

i6/II 

Dampsfchiff 
Fass 

540 

573 

9 

42 

Kuh 

848 

52 

Ballon 

708 

177 

23/11 

Kerze 
Schuh 

839 
897 

61 
3 

23/II 

Fliege 
Schuh 

420 
577 

in 

46 

Nase 

.      813 

87 

Lowe 

607 

76 

18/5 

Ring 
Dampsfchiff 

800 
649 

100 

251 

i8/V 

| 

Veilchen 
Rose 

375 
460 

156 
7i 

12)10,807 

2,055 

Kuh 

363 

168 

900 

171 

13)6,911 

1,242 

Mean     =531 

95 

Median  =  540 

Reaction  to  visual  imagery  equal  to  or  below  median =o. 

SUBJECT  LEHNER 
Words 


Date 

Visual  Image 

T 

v 

Date 

Simple  Meaning 

T 

V 

f  Rechen 

38i 

263 

Schwan 

445 

24 

I6/II 

1  Buch 
|  Rettich 

1,131 
611 

487 
33 

I6/II 

Bohrer 
Sofa 

1,007 
663 

538 

194 

[Nase 

604 

Rose 

317 

152 

Tnchter 

584 

60 

Brief 

691 

222 

Dreieck 

490 

154 

'  Palme 

500 

31 

Blatt 

597 

47 

Baum 

399 

70 

30/VI 

Bar 

Krone 

606 
479 

38 

Hirsch 
Spaten 

389 
406 

80 
63 

Veilchen 

488 

156 

30/VI 

. 

Aal 

407 

62 

Treppe 

631 

13 

Krug 

395 

74 

Ofen 

572 

72 

Tasse 

489 

20 

Sabel 

588 

56 

Schadel 

426 

43 

Geige 

461 

183 

Ohr 

435 

34 

3/VII 

Pfeil 
Meissel 
Fernglas 
Flasche 

874 
758 

193 
129 
230 
114 

3/VII 

' 

Spaten 
Hirsch 
Baum 
Palme 

371 
483 
524 

49 
98 

14 

55 

Krug 

691 

47 

'Bar 

368 

101 

7/VH 

. 

Tasse 
Schadel 

736 
918 

92 
274 

7/VII 

Krone 
Ofen 

384 
429 

85 
40 

Ohr 

844 

200 

Veilchen 

344 

125 

Ballon 

803 

159 

Treppe 

398 

23)14,813 

3,205 

23)10,788 

2,245 

644 

139 

Mean     =469 

97 

Median  =429 

Reaction  to  visual  imagery  equal  or  below  median  =i. 


I92 


T.  V.  MOORE 


SUBJECT  MAREZOLL 

Words 


Date 

Visual  Image 

T 

V 

Date 

Simple  Meaning 

T 

v 

ii/V 

Ohr 
Zwicker 

1,308 
1,633 

221 
104 

ii/V 

Kafer 
Kerze 

841 

638 

254 
051 

Eule 

1,598 

69 

'  Storch 

831 

244 

I2/V 

Schnecke 
Pfau 

1,374 
2,721 

155 

1,192 

I2/V 

Katze 
Kuh 

576 
822 

on 

235 

Kafer 

3,868 

2,339 

Schlange 

761 

174 

I4/V 

Maus 
Schaf 

2,610 
1,309 

i,  08  1 

220 

I4/V 

Lowe 
Stier 

774 
458 

187 
129 

Hirsch 

1,222 

307 

Geier 

325 

262 

Zirkel 

I,2IO 

319 

Ohr 

508 

079 

I6/VI 

Eimer 
Stuhl 

1,021 

947 

508 
582 

i6/VI 

Eule 
Schnecke 

398 
676 

189 
089 

Sichel 

870 

659 

Schlange 

582 

005 

Kerze 

1,187 

342 

Storch 

693 

106 

Geier 

1,367 

162 

i 

Kuh 

650 

073 

Stier 

988 

541 

I9/VI 

Kerze 

465 

122 

I9/VI 

Lowe 
Schlange 

1,607 
1,292 

78 
237 

Katze 
Maus 

684 
456 

097 

Kuh 

*,57! 

42 

Pfau 

436 

151 

Katze 

1,146 

383 

Schaf 

697 

1  2O 

Storch 

1,258 

271 

Hirsch 

384 

203 

30/VI 

Zirkel 
Sichel 

406 
594 

181 
007 

Stuhl 

425 

162 

Eimer 

557 

030 

21)32,107 

9,812 

25)14,687 

3,292 

1,529 

467 

Mean    =587 

152 

Reactions  to  visual  imagery  equal  or  below  median  =  o. 

SUBJECT  MOORE 
Words 


Date 

Visual  Meaning 

T 

V 

Date 

Simple  Meaning 

T 

V 

Schuh 

839 

330 

Finger 

5l6 

53 

Sofa 

1,685 

516 

Buch 

337 

126 

9/VI 

Rechen 
Auge 

1,112 

1,448 

57 
279 

9/VI 

Schere 
Biirste 

444 

572 

19 
109 

Lampe 
Dampsfchiff 

1,145 

857 

24 
312 

Fernglas 
Uhr 

563 
401 

100 

62 

Ochse 

J,553 

384 

Schuh 

484 

21 

I2/VI 

Frosch 

1,009 

Tiger 

758 

295 

Kamm 

794 

375 

I2/VI 

Vogel 

259 

204 

Biirste 

8i5 

354 

Rechen 

386 

77 

, 

Pinsel 

1,091 

78 

Fernglas 

396 

67 

Besen 

1,108 

61 

Sofa 

245 

218 

Handbeil 

1,188 

19 

Kamm 

572 

109 

30/VI 

Vogel 
Tiger 

i'27S 

I4/VII 

Auge 
Frosch 

583 
436 

120 

27 

Uhr 

1,209 

40 

Biirste 

44° 

23 

I4/VII 

\ 

Schere 
f  Schuh 
(  Rechen 

937 
i,44S 
i,544 

232 
276 
375 

Dampfschiff 

iv/r 

478 

IS 

17)7,87° 

ao  r\           A  A'J 

i,645 

ofi 

19)22,209 

3,992 

.L  >  .L  V_  0.  1  1                H"V/J 

Median  =  444 

9° 

1,169 

210 

Reactions  to  visual  imagery  equal  or  before  median  =  o. 


MEANING  AND  IMAGERY 


'93 


SUBJECT  SCHERREN 


Date 

Visual  Image 

T 

V 

Date 

Simple  Meaning 

T 

v 

22/VI 

Krebs 
Stern 

9,807 
4,537 

5,i40 
130 

I3/VII 

Fliege 
Facher 

656 
988 

104 

228 

Herz 

3,370 

1,297 

Finger 

846 

86 

I3/VII 

Trommel 
Spinne 

6,505 
4,587 

1,838 
80 

Herz 
Fliege 

788 
1,034 

28 
274 

Koffer 

2,53i 

2,136 

Stern 

i,  080 

320 

Flasche 

3,159 

1,488 

Krebs 

963 

203 

Hirsch 

3,4H 

1,256 

Koffer 

552 

208 

20/VH 

Sabel 
Traube 

5,354 
5,402 

687 
735 

2I/VII 

Spinne 
Trommel 

697 
561 

63 
199 

Engel 

5,340 

673 

Sabel 

631 

129 

Facher 

2,007 

2,660 

Flasche 

969 

209 

Engel 

378 

382 

Traube 

501 

259 

12)56,010 

18,120 

14)10,644 

2,692 

4,667 

i,5io 

Mean    =760 

192 

Median  =  742 

Reaction  to  visual  imagery  equal  or  below  median  =  o. 

SUBJECT  STAPPEN 
Words 


Date 

Visual  Image 

T 

V 

Date 

Simple  Meaning 

T 

V 

Ring 

572 

87 

Veilchen 

604 

63 

12/11 

Auge 
Ballon 

6l3 

584 

46 
75 

12/11 

Fass 
Kerze 

743 
5H 

202 
27 

Stiefel 

656 

3 

Lowe 

509 

32 

Schaf 
Rettich 

634 
1,076 

25 
417 

17  II 

Rose 
Kuh 

497 
423 

44 
118 

I7/H 

Nase 
Fass 

!6s 

600 

94 

59 

Haken 
Lilie 

573 
507 

32 
34 

Rechen 

^Nest 

657 
874 

2 
215 

I9/H 

Storch 
Sichel 

I11 
614 

30 
73 

Sage 

707 

48 

Lampe 

516 

25 

I9/H 

• 

Maske 

632 

27 

Sofa 

485 

56 

Uhr 

Sl8 

141 

Esel 

537 

122 

14)9,225 

I,36l 

12)6,496 

736 

659 

97 

Mean    =541 

61 

Median  =  5  13 

Reactions  to  visual  imagery  equal  or  below  median  =  o. 

reaction  times  in  thousandths  of  a  second.  Under  V,  the 
variations  from  the  mean. 

At  the  bottom  of  each  column  the  mean  reaction  times 
and  mean  variations  have  been  calculated.  The  median  for 
the  reaction  times  to  meaning  have  also  been  determined. 

With  but  one  exception,  our  nine  subjects  show  a  marked 
difference  in  their  reactions  to  meaning  and  imagery.  The 


i94 


T.  V.  MOORE 

SUBJECT  T 
Words 


Date 

Visual  Image 

T 

v 

Date 

Simple  Meaning 

T 

V 

Kette 

1,129 

58 

Puppe 

747 

255 

Nest 

1,162 

25 

Bretzel 

794 

302 

Trichter 

i,774 

587 

Mond 

754 

262 

Stuhl 

890 

297 

Schadel 

546" 

54 

Anker 

1,306 

119 

Taube 

884 

362 

27/VH 

Ballon 
Auge 

i,257 
i,  216 

70 
29 

27/VII 

Zirkel 
Hirsch 

753 

520 

261 
28 

Apfel 

905 

282 

Engel 

569 

77 

Eimer 

1,295 

108 

Besen 

499 

7 

Ofen 

1,109 

78 

Pferd 

517 

25 

Kuh 

995 

192 

Hund 

498 

6 

Tiger 

1,260 

73 

Geige 

464 

28 

Fass 

1,132 

55 

Schiff 

667 

175 

Strumpf 

879 

308 

Tiger 

347 

H5 

Schrank 

1,263 

76 

Schnecke 

453 

39 

Schlange 

866 

321 

Pfau 

554 

62 

Facher 

1,259 

72 

Fliege 

470 

22 

Herz 

i,845 

658 

Fahne 

441 

51 

Hahn 

947 

240 

Finger 

793 

301 

28/VII 

Krebs 

2,176 

989 

28/VII 

Stern 

369 

123 

Spinne 

329 

Trommel 

335 

157 

Hase 

1,072 

Koffer 

525 

33 

Schlitten 

906 

281 

Nase 

527 

35 

Feile 

354 

Schliissel 

556 

64 

Hand 

900 

287 

Hammer 

479 

13 

Handschuh 

871 

316 

Spaten 

411 

81 

Eule 

999 

188 

Bar 

401 

91 

Kirsche 

921 

266 

'  Klavier 

663 

171 

Lowe 

802 

385 

Kerze 

419 

73 

Leiter 

1,415 

228 

Bleistift 

38i 

in 

Fernglas 

1,677 

490 

Nest 

140 

Wiege 

1,336" 

149 

Wage 

367 

125 

Wurst 

993 

194 

Bohrer 

307 

185 

29/VII 

Loffel 

806 

38i 

29/VII 

Fliege 

304 

188 

Haken 

2,115 

928 

Trommel 

376 

116 

Veilchen 

1,315 

128 

Brille 

362 

130 

Treppe 

919 

268 

Lilie 

369 

123 

Bretzel 

779 

408 

Blatt 

303 

189 

Turm 

894 

293 

Biirste 

312 

1  80 

Trichter 

1,030 

157 

Truthahn 

301 

191 

40)47,472 

10,782 

40)19,689 

4,98i 

1,187 

269 

Mean     =  492 

122 

Median  =  474 

Reactions  to  visual  imagery  equal  or  below  median  =  o. 

one  exception  is  not  to  be  explained  by  individual  difference 
in  mental  type,  but  rather  by  an  anxiety  to  react  as  quickly 
as  possible.  At  first  he  reacted  to  every  nonsense  word. 
He  was  then  tried  with  pictures.  Here  again,  every  meaning- 
less drawing  elicited  a  reaction  in  spite  of  instructions.  The 
reaction  times  at  first  varied  around  100  a.  Later  he  was 


MEANING  AND  IMAGERY 


'95 


asked  to  wait  each  time  and  make  a  judgment  that  he  had 
fulfilled  the  task  given  him.  Even  under  these  instructions, 
he  continued  to  react  occasionally  to  nonsense  words — the 
following  reaction  being  very  much  retarded.  He  finally 
gave  up  the  experiments.  What  would  have  resulted  had  he 
by  practice  become  entirely  free  from  erroneous  reactions 
one  cannot  say.  It  would  seem,  however,  more  fair  to  a  just 
conclusion  to  exclude  rather  than  include  his  results  in  our 
summary.  Leaving  aside  the  results  of  this  subject,  the 
reaction  times  to  visual  imagery  were  all  but  one  above  the 
median  of  the  reaction  time  to  meaning.  It  is  worthy  of  note 
that  this  single  exception  is  the  first  recorded  reaction  of  this 
subject.  (He  had  made  several  practice  series  before.)  Our 
subjects  made  150  reactions  in  all.  Were  it  merely  a  matter 

SUBJECT  MAREZOLL 
Worter 


Visual  Image 

Simple  Meaning 

D 

Ohr.  . 

1,308 

508 

+       800 

Eule 

i  508 

398 

+    I,2OO 

Schnecke 

J    -274. 

676 

+        698 

Pfau 

2,721 

436 

+    2,285 

Kafer 

3,868 

841 

+    3,O27 

Maus 

2,610 

T* 

456 

+   2,154 

Schaf      . 

i,  300 

J3 

697 

+     612 

Hirsch    . 

1,222 

384 

4-     838 

Zirkel      . 

I,2IO 

406 

+     804 

Eimer  

I,  O2  1 

cc7   • 

~i~      464 

Stuhl  

Q4-7 

42  C 

+   522 

Sichel  

870 

CQ4 

+   376 

Kerze  

1,187 

638 

ji 

4-       1:40 

Geier  

1,367 

325 

3T7 

T    1,042 

Stier 

088 

4C8 

4-           C-2Q 

Lowe 

yoo 
I  6O7 

m^mrcw 

->J 

+       QT? 

Schlange 

I  2Q2 

f 
76l 

+       531 

Kuh. 

1,  571 

822 

4-       7cn 

Katze.  .  . 

1,14-6 

576 

+        C7O 

Storch  

1,258 

y 

693 

+    565 

20)30,474 

",425 

19,259  ' 

15237 

571.2 

962.9 

of  chance  that  reaction  times  to  imagery  should  be  longer  than 
those  to  meaning  we  could  find  about  75  longer  and  75  shorter. 
As  a  matter  of  fact,  we  find  149  longer  and  only  one  shorter. 
In  spite  then  of  the  rather  small  number  of  reactions  (condi- 
tioned by  taking  the  introspective  reports)  there  is  over- 


196  T.  V.  MOORE 

whelming  evidence  to  show  that  something  more  than  chance 
has  to  do  with  the  difference  in  reaction  time  to  meaning  and 
imagery.  This  difference  is  not  due  to  the  words  used  for 
imagery  and  meaning.  Not  only  were  the  words  in  both 
cases  representative  of  sensory  objects  but  care  was  taken  to 
repeat  the  same  words  in  the  two  series.  A  table  is  given 
above  comparing  the  reactions  of  one  subject  for  meaning 
and  imagery  to  the  same  words.  Under  D  is  given  the 
difference  between  the  two.  The  reaction  time  to  imagery  is 
always  longer  than  to  meaning.  With  some  of  our  subjects 
the  results  are  not  so  unanimous,  the  meaning  reaction  being 
occasionally  longer.  This  is  to  be  explained  mainly  by  the 
effects  of  practice,  though  something  is  no  doubt  due  to 
accidental  variation. 

(b)  INTROSPECTIVE  DATA 

From  the  quantitative  results  that  have  just  been  given, 
it  is  evident  that  the  subjects  give  a  different  response  when 
told  to  react  to  meaning  or  imagery.  Were  we  to  stop  with 
the  quantitative  results  we  would  not  know  very  much  about 
the  nature  of  that  difference.  Is  meaning  simply  an  early 
stage  in  the  development  of  the  image?  Is  it  a  vague  con- 
fused image?  Is  it  merely  the  realization  of  the  power  to 
visualize  the  object?  Is  it  the  tendency  of  a  number  of 
images  to  crowd  into  consciousness?  What  is  the  difference? 
There  can  be  no  doubt  that  a  considerable  difference  exists 
and  it  is  of  great  importance  to  find  out  precisely  what  it 
is.  This  can  be  done  by  an  examination  of  the  subjects' 
introspective  reports  of  what  they  experienced  during  their 
reactions.  The  reports  were  taken  down  by  dictation  imme- 
diately after  the  reaction  and  then  re-read  to  the  subject  to 
insure  their  accuracy.  The  originals  are  in  German  and 
will  be  given  in  German  and  in  English  when  a  complete 
account  of  all  the  experiments  is  published. 


MEANING  AND  IMAGERY 


197 


CONSCIOUSNESS  OF  MEANING 

(1)  The  meaning  has  a  general  character. 
Kerze:  "  There  came  to  me  at  once  the 

word  'Light.'  This  was  not  a  determina- 
tion of  the  meaning,  but  only  another 
word  for  it.  The  meaning  was  entirely 
general,  as  if  I  should  say  a  candle,  that 
is,  any  candle — every  possible  candle." 
-Kiilpe,  9/H. 

(2)  The  universality  of  the  meaning  is 
not  always  absolute. 

Ring:  "As  soon  as  I  saw  this  word,  I 
experienced  an  auditory  motor  stimulus, 
and  immediately  in  connection  therewith 
the  understanding  of  that  which  the  word 
signified.  This  was  quite  universal  with- 
out being  related  to  anything  in  partic- 
ular— except  the  limitation  to  'finger- 
ring.'  I  am  distinctly  conscious  that  a 
finger-ring  was  intended.  I  cannot  re- 
member an  image  of  any  such  ring." 
—Kiilpe,  13/11. 

(3)  The  meaning  is  at  times  felt  to  be  in- 
complete, because  of  an  unanalyzed  con- 
sciousness of  what  the  word  signifies. 

Schere:  "At  first,  a  feeling  of  familiar- 
ity was  present  and  then  a  feeling  of  cer- 
tainty that  I  know  what  the  word  sig- 
nifies without  having  analyzed  its  mean- 
ing any  further.  First,  during  the  reac- 
tion itself  there  came  the  further  thought 
'something  with  which  one  cuts.'" 
— Moore,  9/VI. 


Eule:  "I  knew  that  the  word  was  some- 
thing with  which  I  am  familiar  and  knew 
that  from  this  point  I  could,  at  any  time, 
go  on  and  find  its  more  specific  meaning. 
Thereupon  I  reacted.  In  the  word  itself 
there  was  something  presented  to  con- 
sciousness (mir  gegeben)  that  I  cannot 
further  describe."— Frl.  Marezoll,  io/VI. 


CONSCIOUSNESS  OF  VISUAL  IMAGERY 

(1)  The  image  is  particular. 

Sofa:  "  I  have  a  rather  good  image  and 
I  did  not  pronounce  the  word.  I  see  with 
great  precision  the  brown  cobr  and  the 
form  of  the  object — but  not  of  the  entire 
object.  I  could  derive  several  concepts 
from  this  one  image.  It  looks  like  a  large 
reclining  chair.  The  image  would  not  do 
for  all  sofas." — Griininger,  i6/II. 

(2)  The  image  is  at  times  schematic. 
Herz:   "I  read  the  word  'heart'  and 

apprehended  its  meaning.  I  remembered 
my  task  and  sought  after  an  image.  I 
projected  over  the  place  of  the  card  a 
heart  of  regular  mathematical  propor- 
tions. Only  the  contours  were  imaged, 
and  these  by  such  an  airy  line  that  I 
question  myself  whether  I  had  a  visual 
image  at  all  or  whether  it  was  an  ideal 
construction,  such  as  one  ca'rries  out 
in  mathematical  thinking." — Scherren, 
I3/VII. 

(3)  The  image  is  at  times  incomplete  in 
a  different  way. 

(i)  It  is  partial. 

Rechen:  "First,  the  meaning,  then  the 
image.  Nevertheless,  I  reacted  before  the 
image  was  clear.  I  imaged  a  part  of  a 
rake.  Already  I  have  noted  several 
times  that  I  image  the  left  lower  parts  of 
objects.  Here  I  imaged  a  wooden  rake." 
— Stappen,  17/11. 

(ii)  It  represents  a  single  definite  char- 
acter of  an  object. 

Kuh:  "I  have  the  meaning  and  now  I 
must  have  an  image.  I  then  look  at  an 
empty  spot — no  longer  at  the  word. 
Then  there  appears  the  color  of  the  ani- 
mal. I  see 'brown.'  But  a  satisfactory, 
complete  image,  I  do  not  obtain.  I  must 
exert  myself  even  to  obtain  the  color.  I 
could  not  take  the  image  for  the  meaning. 
I  cannot  read  anything  more  out  of  the 
image  than  'brown' — never  the  meaning 
'cow.'" — Griininger,  i6/II. 


i98 


T.  V.  MOORE 


CONSCIOUSNESS  OF  MEANING 
(4)  The    meaning    never    has    sensory 
characteristics  but  rather  a  conceptual  de- 
termination. 

Geier:  "A  moment  passed  before  I 
found  the  meaning.  No  auditory-kinses- 
thetic  image  was  present.  I  knew  that  it 
was  something  that  hovers  over  moun- 
tains in  the  air — even  though  I  did  not 
see  the  mountains.  Visually  I  imaged 
only  a  pair  of  extended  wings  and  knew 
that  something  belonged  between  them." 
— Frl.  Marezoll,  I4/V. 


Veilchen:  Immediately  after  the  word 
appeared,  I  had  an  auditory-kinaesthetic 
image  of  it — as  I  pronounce  it.  'Veil- 
chen,' and  in  connection  therewith  a 
knowledge  of  its  meaning  (Ein  allge- 
meines  Bedeutungswissen),  that  I  can 
thus  explain:  a  definite  species  of  flower. 
I  dare  say  that  it  is  this  which  makes  up 
the  content  of  the  meaning — what  I  actu- 
ally know  about  this  object  during  the  ex- 
periment.— Kiilpe,  i8/V. 

(5)  The  meaning  is  often  expressed  in 
terms  of  a  definition  of  general  applica- 
tion. 

Dampfschiff :  Immediately  on  the  expo- 
sition of  the  word,  auditory-kinsesthetic 
image  thereof,  and  a  realization  of  the 
meaning  in  the  sense  of  'a  means  of  trans- 
port by  water.'  This  time  there  was  no 
trace  of  any  image. — Kiilpe,  i6/II. 


(6)   The  meaning  is  never  localized. 


CONSCIOUSNESS  OF  VISUAL  IMAGERY 
(4)   The    image    manifests    degrees    of 
brightness,  color  and  clearness. 

Rose:  "Immediately  after  the  word 
came  I  had  the  auditory-kinsesthetic 
image  of  the  word  and  thereupon  an 
understanding  for  its  general  significa- 
tion. Then  first  came  an  image — the 
image  of  a  blossom.  Almost  nothing  of 
the  stem  was  seen.  Colorless,  mere  dif- 
ferences of  brightness  in  the  blossom 
and  the  leaves  were  perceived.  A  full 
blown  rose.  The  common  form.  Image 
and  meaning  did  not  cover  each  other." 
—Kiilpe,  I6/II. 

Krug:  Meaning  then  the  visual  image. 
It  was  an  earthenware  jug,  bellied  out  in 
front — antique  as  if  it  had  just  been  dug 
up. — Lehner,  7/VII. 


(5)  The  image  is  often  described  in  sen- 
sory terms  that  would  fit  only  a  very  definite 
object. 

Rettich :  This  time  there  came  to  me  the 
image  of  a  radish  of  medium  size.  I  saw 
clearly  the  little  hollows  in  its  skin  filled 
with  dirt  and  myself  in  the  attitude  in 
which  I  cultivate  this  beautiful  variety  in 
my  wife's  garden.  All  at  once  there 
came  to  me  a  poem  of  Morike.  It  is  en- 
titled 'The  Radish.'— Lehner,  i6/II. 

(6)  The    image    has    often    a    definite 
position. 

Schuh:  I  had  an  indistinct  image  of  a 
laced  shoe — the  point  to  the  right  some- 
what behind  the  plane  of  the  word.  A 
confused  consciousness  of  meaning  was 
also  immediately  present,  which  did  not 
coincide  with  the  image.  The  meaning 
was  even  more  general  than  foot  covering. 
It  had  somewhat  the  sense  of  a  piece  of 
clothing  without  relation  to  a  part  of  the 
body. — Kiilpe,  23/11. 


MEANING  AND  IMAGERY 


199 


CONSCIOUSNESS  OF  MEANING 
(7)   The  meaning  is  always  pertinent  to 
the  word. 


(8)   The  meaning  is  never  looked  upon  as 
superfluous. 


(9)   The  meaning  is  always  present. 


(10)  The  meaning  leads  regularly  to  the 
image. 

Nearly  always  the  subjects  report  the 
meaning  as  coming  first. 


•     CONSCIOUSNESS  OF  VISUAL  IMAGERY 

(7)  The  image  is  sometimes  recognized 
as  not  strictly  pertaining  to  the  word. 

Rettich:  The  word  appeared  very 
strange  to  me.  I  think  I  read  something 
like  'Bettish.'  Only  later  did  I  get  the 
correct  meaning.  There  came  a  visual 
image.  The  image  did  not  really  repre- 
sent a  radish  but  rather  a  kind  of  turnip. 

(8)  The  image  is  often  regarded  as  un- 
necessary and  of  secondary  importance. 

Ochs:  I  first  understood  the  word  as 
something  familiar,  as  something  that  I 
knew  what  it  was.  A  further  analysis  of 
the  meaning  did  not  take  place.  Under 
the  influence  of  the  task,  my  attention 
was  directed  to  experiencing  an  image  and 
then  arose  the  head  of  an  ox  with  his 
horns  as  drawn  in  the  pictures  for  these 
experiments. — Moore,  I2/VI. 

Fass:  Immediately  after  looking  at  the 
word  an  auditory-kinsesthetic  representa- 
tion and  understanding  of  its  general  sig- 
nification in  the  sense  of  a  spatial  meas- 
ure. There  came  also — altogether  fleet- 
ingly  a  weak  image  with  a  pair  of  hoops 
lying  on  the  ground — wholly  accessory  as 
if  a  schema. — Kiilpe,  i6/II. 

(9)  The  image  is  often  lacking. 

Such  cases  could  be  multiplied  indefi- 
nitely. Some  have  already  been  given. 

(10)  The   image   is   only   occasionally 
present  before  the  meaning. 

Kuh:  I  believe1  the  image  came  first — 
wholly  undefined.  Very  soon  thereafter 
the  meaning,  immediately  after  which  the 
reaction. — Stappen,  17/11. 


(n)   The  meaning  comes  spontaneously. 

Cases  enough  have  already  been  cited 
to  make  this  evident.  Only  occasionally, 
where  the  word  is  read  incorrectly,  is  any 
effort  required  to  bring  out  this  meaning. 


The  image  must  often  be  sought. 
Flasche:  I  had  the  feeling  of  a  consider- 
ably retarded  flow  of  imagery,  and  per- 
ceived clearly  that  I  was  sharply  concen- 
strated  upon  my  task.  I  then  imagined 
that  I  went  through  Amalien  Street  and 

1  These  cases  are  very  rare.  I  have  found  them  only  with  this  subject  and  when 
he  does  mention  them,  it  is  always  with  reserve.  He  says  'I  believe'  indicating  that  he 
is  not  sure  of  the  observation. 


200  T.  V.  MOORE 

CONSCIOUSNESS  OF  MEANING  CONSCIOUSNESS  or  VISUAL  IMAGERY 

had  the  task  to  represent  to  myself  a 
bottle.  The  representation  succeeded 
but  rather  poorly.  Only  the  image  of 
the  material  (glass)  and  the  long  form 
was  clear. — Lehner,  3/VII. 

A  careful  consideration  of  these  results  will  show  that 
the  difference  between  meaning  and  visual  imagery  does  not 
consist  in  any  possible  difference  in  the  original  imagery  itself. 

If  meaning  were  an  early  stage  in  the  development  of  the 
visual  imagery,  it  might  be  possible  to  explain  in  this  way 
the  difference  in  the  reaction  times  to  the  two  events.  A 
candid  consideration  of  the  introspections  shows  that  this  is 
not  the  case.  The  universality  of  the  meaning  cannot  be 
pictured  and  is  something  quite  different  from  the  schematism 
of  the  image.  The  incompleteness  of  the  image  with  a 
fragmentary  character  and  washed  out  coloring  differs  pro- 
foundly from  the  imperfect  unanalyzed  embryonic  stage  of 
the  meaning.  The  image  has  sensory  characters  which 
cannot  be  ascribed  to  the  meaning — the  meaning  cognative 
characters  which  are  utterly  foreign  to  the  image.  The 
meaning  is  a  'knowing'  sui  generis;  the  image  is  a  sensational 
element  with  its  own  specific  character. 

The  meaning  is  not  the  potentiality  to  visualize.  It  may 
have  an  element  of  potentiality  about  it,  but  it  always  has 
an  element  of  actuality  which  extends  from  the  unanalyzed 
knowledge  expressed  by  the  phrase:  "I  know  what  that  is" 
— to  the  more  perfect  conception  expressed  by  a  definition. 
The  potentiality  of  the  meaning  when  present  is  not  the 
same  for  all  meanings.  It  is  a  definite  potentiality  in  which 
the  elements  of  a  definition  of  the  object  are  in  subconscious- 
ness.  It  is  not  the  potentiality  to  visualize,  for  the  poten- 
tiality to  visualize  (i)  depends  on  a  meaning  to  determine 
what  is  to  be  visualized;  (2)  results  in  something  different 
from  the  actualization  of  the  meaning.  The  actualization  of 
the  meaning  leads  to  the  consciousness  of  a  definition  which 
may  not  even  be  accompanied  by  imagery  of  any  kind 
whatever. 

Nor  is  imagery  the  tendency  of  a  number  of  images  to 


MEANING  AND  IMAGERY  201 

crowd  into  consciousness.  That  tendency  is  sometimes  pre- 
sent especially  with  one  of  our  subjects,  but  by  him  it  was 
recognized  as  something  that  came  after  the  meaning.1 

Meaning  is  often  present  and  one  is  definitely  conscious 
of  it  without  being  conscious  of  a  tendency  of  images  to  crowd 
into  consciousness.  Meaning  is  a  consciousness  of  knowledge 
that  has  definite  characters  foreign  to  the  images  that  tend 
to  crowd  into  consciousness.  Furthermore,  where  images  do 
crowd  into  consciousness  they  have  to  be  known.  This 
knowledge  of  what  the  image  represents  cannot  be  explained 
by  another  image  which  would  itself  have  to  be  known. 

Meaning,  therefore,  appears  to  be  a  conscious  process 
sui  generis  distinct  from  imagery. 

IV.    CONSCIOUSNESS    OF    PURPOSE    AND    KIN^ESTHETIC 

IMAGERY 

(a)  Quantitative  Results 

The  instructions  to  the  subject  indicate  sufficiently  the 
nature  of  the  investigation  in  this  section  of  the  work.  These 
instructions  were  as  follows: 

Sie  werden  nach  einem  Signal  ein  Wort  zu  sehen  bekom- 
men.  Ich  bitte  Sie  zu  reagieren  wenn  Sie  die  Bedeutung  des 
Wortes  im  Hinblick  auf  den  Gebrauch  oder  die  Funktion  des 
damit  bezeichneten  Gegenstandes  erfasst,  bzw.,  wenn  Sie 
eine  kinaesthetische  oder  kinaesthetisch-optische  Vorstellung 
davon  gehabt  haben. 

The  words  chosen  for  reaction  stimuli  in  this  set  were  not 
merely  capable  of  being  visualized  but  represented  objects 
that  most  of  us  have  often  handled  as:  brush,  bell,  hat.  To 
represent  a  word  like  'lion'  by  a  kinsesthetic  image  is  to  some 
subjects  a  very  difficult  task.  Consequently  a  more  appro- 
priate set  of  words  was  chosen.  Even  under  the  most  favor- 
able conditions  the  kinaesthetic  image  comes  far  too  late  to 
account  for  the  meaning.  It  might,  however,  be  claimed 
that  such  an  image  is  identical  with  the  consciousness  of  the 
purpose  of  an  object.  Accordingly  the  comparison  was  made 
between  reactions  to  the  consciousness  of  purpose  and  those 

1  Cf.  supra,  p.  178.     Subject  Lehner. 


2O2 


T.  V.  MOORE 


to  the  awareness  of  a  kinaesthetic  image  which  concerned 
the  object  itself.  Mere  verbal  images  were  excluded.  Seven 
subjects  took  part  in  this  set  of  experiments. 

The  results  are  shown  in  the  accompanying  tables: 

SUBJECT  GRUNINGER 
Words 


Date 

Motor  Image 

T 

V 

Date 

Concept  of 
Purpose 

T 

V 

Anker 

2,084 

210 

f  Stiefel 

2,247 

699 

2/III 

Rechen 

1,647 

647 

2/III 

Koffer 

,389 

159 

Gabel 

1,929 

365 

Biirste 

,292 

256 

Trichter 

2.379 

85 

'  Flasche 

,671 

123 

Apfel 
Wiege 

2,307 
2,448 

13 
154 

Wurst 
Birne 

7H 

1,255 

834 
293 

Eimer 

1,690 

604 

Brief 

,474 

74 

4/III 

< 

Kette 
Zwicker 

2,398 

2,101 

I04 
193 

4/111 

Leiter 
Fahne 

,4H 

2,255 

134 

707 

Treppe 

2,506 

212 

Finger 

i,458 

90 

Hund 

3,745 

1,451 

Kuh 

i,474 

74 

11)25,234 

4,038 

Ente 

1,942 

394 

2,294 

367 

12)18,585 

3,837 

Mean     =  1,548 

320 

Median  =  1,466 

Number  of  times  median  for  concept  exceeds  reaction  time  for  imagery  =  o. 

SUBJECT  KULPE 
Words 


Date 

Kinsesthetic 
Image 

T 

V 

Date 

Concept 
of  Purpose 

T 

V 

27/H 

2/III 

Ring 
\  Sichel 
Ring 
Rechen 
Bleistift 
Wurfel 
Lampe 
Pickel 

,100 

,416 

,332 
,823 
,227 

,579 
,298 
,638 

45i 
135 
219 

272 

324 
1,028 

253 
87 

27/H 

2/III 

• 

'  Stiefel 
Auge 
>  Haken 
Hammer 
Biirste 
Gabel 
Feile 
Uhr 
Stiefel 

Mea 
Med 

804 
1,180 
771 
1,822 
1,346 
1,165 

1,153 
808 

944 

306 

70 

339 
712 
236 
55 
43 
302 
166 

8)12,413 
1,55! 

2,769 

346 

9)9,993 

2,229 

n    =1,110 
ian  =  i,i53 

247 

Number  of  times  median  for  concept  exceeds  reaction  time  for  imagery  =i. 

With  all  of  our  subjects  the  mean  for  reaction  time  to 
kinaesthetic  imagery  is  longer  than  that  to  the  concept  of 
purpose.  Examining  these  results  critically  we  find  that 
with  some  of  our  subjects  in  spite  of  the  small  number  of 


MEANING  AND  IMAGERY 


203 


SUBJECT  LEHNER 
Words 


Date 

Kinaesthetic 
Image 

T 

V 

Date 

Concept  of 
Purpose 

T 

v 

f  Wiirfel 

1,083 

70 

f  Feile 

997 

7i 

2/III 

\  Lampe 

I55i5 

362 

2/III 

Uhr 

1,249 

323 

I  Pickel      . 

1,184 

31 

Stiefel 

1,121 

J95 

Brief 

1,693 

540 

Wiege 

684 

242 

Leiter 

i,H5 

8 

Eimer 

1,050 

124 

5/ni 

Fahne 

1,501 

348 

5/ni 

Kette 

733 

193 

Flasche 

1,980 

827 

Zwicker 

815 

in 

Treppe 

1,162 

9 

Finger 

1,260 

334 

Stiefel 

760 

393 

Brief 

941 

15 

Uhr 

804 

349 

Leiter 

1,076 

J5° 

Feile 

941 

212 

Fahne 

960 

34 

23/VI 

Wiege 

826 

327 

Flasche 

937 

ii 

Eimer 

879 

274 

23/VI 

Treppe 

763 

163 

Kette 

882 

271 

Wiirfel 

738 

188 

Zwicker 

927 

226 

Lampe 

721 

205 

Finger 

1,170 

17 

Pickel 

775 

I5i 

16)18,452 

4,264 

16)14,820 

2,510 

1,153 

266 

Mean     =  926 

157 

Median  =  937 

Number  of  times  median  for  concept  exceeds  reaction  time  for  imagery  =  6. 

SUBJECT  MAREZOLL 
Words 


Date 

Kinaesthetic 
Image 

T 

V 

Date 

Concept 
of  Purpose 

T 

v 

14/5 

/Buch 
\  Klavier 

,157 
,899 

493 
249 

H/5 

• 

i  Ring 
Schere 

962 
1,215 

353 

100 

Eimer 

,148 

498 

Pinsel 

1,942 

627 

I9/V 

Korb 
Pinsel 

,745 
,643 

95 
7 

I9/V 

Zirkel 
Schlitten 

1,966 
1,404 

651 

89 

Zirkel 

,524 

2,874 

Schere 

2,167 

852 

Schlitten 

,573 

77 

Eimer 

3,°97 

1,782 

7/VH 

Schere 
Ring 

,071 
723 

579 
927 

30/VI 

Korb 
Buch 

*77  f*  * 

650 
857 

665 
458 

Anker 

,884 

234 

Klavier 

807 

508 

Besen 

,270 

380 

Burste 

930 

385 

*9/VII 

Bohrer 
Burste 
Zwicker 

,422 
,218 
,557 

228 
432 
93 

7/VH 

Bohrer 
Besen 
Anker 

990 

749 
1,056 

& 

259 

Rechen 

,532 

118 

Haken 

939 

376 

Horn 

,069 

58i 

Meissel 

,616 

34 

17)28,051 

7,899 

I5)i9,73i 

7,996 

1,650 

464 

Mean     =  1,315 

533 

Median  =     990 

Number  of  times  median  for  concept  exceeds  reaction  time  for  imagery  =  o. 


204 


T.  V.  MOORE 


SUBJECT  MOORE 
Words 


Date 

Kinaesthetic 
Image 

T 

V 

Date 

Concept  of 
Purpose 

T 

V 

Bohrer 

,453 

217 

f  Handbeil 

781 

36 

I6/VI 

Spaten 
Haken 

,129 
,628 

S4i 

42 

I6/VI 

Sabel 
Pinsel 

1,162 
592 

345 

225 

Messer 

,796 

126 

Besen 

539 

278 

o  /T  7T 

Biirste 

,772 

102 

'  Nadel 

918 

101 

i8/VI 

Zange 

,396 

274 

I8/VI 

Rechen 

815 

2 

'Handbeil 

,572 

98 

Feile 

1,046 

229 

9/VH 

Pinsel 
Pfeil 

,914 

,222 

244 

448 

9/VH 

Bohrer 
Spaten 

1,004 
564 

I87 
253 

Besen 

,480 

190 

Haken 

836 

19 

'Wage 

,461 

209 

Hammer 

1,215 

398 

Brille 

,896 

226 

Handschuh 

412 

405 

Feile 

,O7I 

401 

Loffel 

635 

182 

Kerze 

,459 

211 

Schlitten 

1,001 

I84 

30/VII 

Ring 
Zange 

,234 
,722 

564 

52 

3o/vn 

Leiter 
Schliissel 

719 
669 

98 

I48 

Bohrer 

,564 

106 

Rechen 

967 

150 

Haken 

,888 

218 

Spaten 

822 

5 

Schere 

,729 

59 

Pinsel 

1,028 

211 

Zirkel 

2,014 

344 

Biirste 

621 

I96 

20)33,400 

4,672 

20)16,346 

3,652 

1,670 

234 

Mean     =  817 

I83 

Median  =  818 

Number  of  times  median  for  concept  exceeds  reaction  time  for  imagery =o. 

SUBJECT  STAPPEN 
Words 


Date 

Kinsesthetic 
Image 

T 

V 

Date 

Concept  of 
Purpose 

T 

V 

28/11 

f  Kerze 
Haken 
Biirste 
Wiirfel 
Sense 

4,308 

f8 
644 

465 
1,024 

2,915 
865 

749 
928 

369 

28/11 

Auge 
Sage 
Sichel 
Gabel 
Feile 

Me 
Me< 

1,199 
682 

697 
8I4 
362 

449 

68 

53 

388 

5)6,969 
1,393 

5,826 

5)3,754 
m     =  750 
lian  =  697 

1,022 

1,165 

2O4 

Number  of  times  median  for  concept  exceeds  reaction  time  for  imagery =3. 

experiments  we  can  say  definitely  that  the  concept  of  purpose 
comes  quicker  than  the  kinaesthetic  imagery.  With  these 
subjects  the  median  for  the  concept  of  purpose  was  shorter 
than  everyone  of  the  reaction  times  to  kinaesthetic  imagery. 
With  one  subject,  one  out  of  eight  reactions  to  kinaesthetic 
imagery  was  shorter  than  the  median;  with  another  two  out  of 


MEANING  AND  IMAGERY 


205 


SUBJECT  TANNHAUSER 
Words 


Date 

Kinsesthetic 
I  mage 

T 

V 

Date 

Concept  of 
Purpose 

T 

V 

Bohrer 

1,492 

231 

Klavier 

1,314 

456 

Schliissel 

939 

322 

Burste 

749 

109 

Trichter 

,527 

266 

Fernglas 

749 

109 

Bleistift 

,367 

106 

Haken 

1,069 

211 

Trommel 

,088 

173 

Leiter 

829 

29 

30/VII 

. 

Brille 

,903 

642 

30/VII 

Kerze 

885 

27 

Rechen 

,327 

66 

Pickel 

1,071 

213 

Tasche 

,255 

6 

Zange 

1,816 

958 

Wage 

,378 

117 

Ring 

785 

73 

Hammer 

,005 

256 

Schlitten 

600 

258 

Handschuh 

,158 

103 

Feile 

763 

95 

Besen 

,173 

88 

Spaten 

554 

304 

Dolch 

855 

406 

Brief 

554 

304 

Horn 

1,011 

250 

Anker 

739 

119 

Auge 

2,334 

1,073 

Eimer 

1,114 

256 

Brunnen 
Geige 

2,216 
694 

955 

567 

Hut 
Flasche 

976 

34 
118 

Fass 

2,006 

745 

Glocke 

717 

141 

Hahn 

2,082 

821 

Facher 

648 

210 

Beil 

i>S76 

315 

Finger 

i,  006 

I48 

3I/VH 

Messer 

831 

430 

31^11 

Fahne 

875 

17 

Lampe 

883 

378 

Meissel 

834 

24 

Koffer 

797 

464 

Korb 

952 

94 

Buch 

1,009 

252 

Kette 

8i7 

4i 

Hobel 

1,007 

254 

Kamm 

816 

42 

Handbeil 

707 

554 

Schrank 

637 

221 

Schuh 

848 

413 

Sense 

776 

82 

Ofen 

849 

412 

Pfeil 

700 

IS8 

28)35,317 

10,665 

Nadel 

720 

138 

1,261 

"~38i~ 

29)24,889 

4,989 

Mean     =  858 

172 

Median  =  816 

Number  of  times  median  for  concept  exceeds  reaction  time  for  imagery =2. 

twenty-eight.  With  one  of  our  subjects  the  matter  looks  a 
little  doubtful;  six  out  of  sixteen  are  shorter  than  the  median. 
With  another  subject1  the  results  are  too  few  and  scattered 
to  give  any  quantitative  basis  for  judgment. 

The  question  is  one  where  individual  differences  are  likely 
to  play  a  part.  Those  who  readily  form  kinsesthetic  imagery 
may  be  able  to  obtain  such  an  image  more  quickly  than  they 
can  think  of  the  purpose  of  the  object.  To  what  extent  this 
is  true  cannot  be  decided  from  the  present  results.2 

1  It  was  impossible  to  get  more  experiments  from  this  subject.     He  left  the  day 
after  the  series  above  reported  and  did  not  return  in  the  summer  semester.     They 
are  more  of  the  nature  of  a  preparatory  series  than  final  results. 

2  When  a  short  abstract  from  this  paper  was  read  last  December  at  the  meeting 


206  T.  V.  MOORE 

Taking  all  the  results  together  only  12  out  of  105  reactions 
to  kinaesthetic  imagery  were  shorter  than  the  median  of  the 
various  subjects'  reaction-times  to  the  concept  of  purpose. 

(b)  Introspective  Data 

Turning  now  to  the  introspective  results,  we  find  that 
the  concept  of  purpose  and  the  kinsesthetic  image  are  very 
clearly  differentiated.  The  concept  of  purpose  differs  from 
the  simple  meaning  in  that  it  does  not  come  with  the  same 
necessity.  It  is  the  result  of  the  subject's  task — not  of  the 
mere  exposition  of  the  stimulus.  The  same  is  true  of  the 
kinsesthetic  image.  Both  follow  upon  the  awareness  of  the 
simple  meaning.  Neither  is  a  necessary  prelude  nor  a  se- 
quence of  the  other.  The  task  "image"  or  "concept"  is  the 
main  factor  in  determining  which  is  to  appear. 

The  following  are  some  of  the  more  noteworthy  intro- 
spective differences  between  the  two. 

(1)  The  concept  of  purpose  is  expressed  (i)   The  kinasthetic  image  always  de- 
in  non-sensory  conceptual  terms.                        scribes  some  kind  of  act  involving  a  use  of 

the  muscles. 

Zwicker:" I  imaged  my  own  eye  glasses  Sichel:  "Immediately  after  the  word 

and  had  clearly  a  consciousness  of  con-  appeared  I  had  an  auditory-kinsesthetic 

cave  glasses.     I  was  further  conscious  of  image  of  it.     Following  this  I  constructed 

the  fact  that  these  glasses  must  refract  a  visual   and   weak  kinaesthetic  image 

the  rays  of  light  according  to  a  definite  thereof  in  this  manner.     I  held  a  sickle  in 

law  that  the  image  may  still  fall  upon  the  my  right  hand   and  made  movements 

retina — even  though  the  lens  is  incapable  therewith   as   if  I   were   cutting  grass. 

of  doing  it  this  service.     I  then  formu-  Thereupon  I  reacted."— Kiilpe,  2/III. 
lated  the  purpose  of  eye-glasses  as:  'The 
correction  of  an  error  of  refraction.'" — 
Lehner,  s/III. 

(2)  The  concept  of  purpose  sometimes  (2)   This  was  not  noted  in  the  description 
involves  the  consciousness  of  the  relation  of        of  the  kinasthetic  imagery. 

the  object  to  other  things. 

Gabel:  "Immediately  after  the  appear- 
ance of  the  word  an  auditory-kinaesthetic 
image  thereof.  Then  came  the  know- 

of  the  Southern  Society  for  Philosophy  and  Psychology,  Professor  Ogden  stated  that 
he  had  reported  some  years  ago  at  one  of  the  meetings  a  series  of  experiments  similar 
to  the  present  in  all  details.  He  never  published  his  results,  but  they  were  identical 
with  my  own.  In  the  interests  of  a  better  insight  into  individual  differences  it  is  to  be 
hoped  that  Professor  Ogden  will  some  day  give  us  the  advantage  of  his  unpublished 
results. 


MEANING  AND  IMAGERY 


207 


ledge  that  the  fork  is  an  instrument  for 
eating,  accompanied  by  a  weak  visual 
image  of  a  fork.  I  was  also  conscious  that 
'fork'  stands  in  relation  to  'knife.'" — 
Kulpe,  2/III. 

(3)  The  concept  of  purpose  though  often 
restricted  to  one  of  various  possible  ends  has 
always  a  certain  generality. 

Kette:  "I  pictured  to  myself  a  toler- 
ably strong  chain  and  remembered  from 
the  days  of  my  youth  that  such  chains 
were  used  to  tie  animals  in  their  stalls.  I 
saw  the  whole  situation  of  that  day  rise 
up  before  me." — Lehner,  5/III. 


(4)  The  consciousness  of  purpose  seldom 
stops  with  a  means  but  rests  in  a  concept 
conceived  of  as  the  object's  end. 

Uhr:  "Immediately  after  the  appear- 
ance of  the  word  I  had  an  auditory-kinaes- 
thetic  image,  then  the  thought:  'The 
clock  must  be  wound  up!'  and  then  the 
further  thought:  'The  clock  tells  the 
time!'  Then  I  reacted.  Weak  visual 
image  of  a  clock  on  a  wall." — Kiilpe, 

2/III. 


(5)  The  concept  of  purpose,  even  though 
delayed,  comes  as  a  natural  development  of 
thought  about  the  object. 


(3)  The  kinasthetic  image  is  often  per- 
fectly definite  and  limited  to  an  individual 
act  in  a  certain  time  and  place. 

Pickel:  "I  imaged  a  pick-ax,  such  as  is 
used  for  working  hard  ground  and  saw 
myself  in  my  garden  in  the  act  of  lifting  it 
in  the  air.  The  consciousness  of  the 
purpose  of  a  pick-ax  is  a  psychological 
process  which  cannot  be  identified  with 
the  act  of  lifting  it." — Lehner,  2/V. 

Wiege:  "The  meaning  aroused  the 
image  of  a  cradle.  I  go  back  in  thought 
to  my  childhood  and  feel  how  I  rock  my 
brother.  The  kinaesthetic  image  in  this 
case  contains  a  great  part  of  the  purpose." 
— Griininger,  4/III. 

(4)  The    kinasthetic    image    regularly 
concerns  an  art  which  is  a  means  to  the 
object's  end. 

Lampe :  "  I  imaged  the  lamp  that  I  use 
in  my  dwelling,  and  saw  clearly  that  it 
did  not  burn  brightly  enough,  and  then 
imaged  the  turning  up  of  the  wick.  The 
kinaesthetic  image  of  the  movement 
cannot  be  identified  with  the  conscious- 
ness of  purpose." — Lehner,  2/III. 

Trichter:  "Immediately  after  the 
simple  meaning  of  the  word,  I  had  the 
visual  image  of  a  funnel  and  then  the 
kinaesthetic  image  of  laying  hold  of  it 
with  my  right  hand  and  placing  it  over 
an  opening.  Here  also  the  kinaesthetic 
image  falls  short  of  being  the  fulfilment  of 
the  purpose.  For  I  think  that  the  funnel 
is  the  instrument  by  means  of  which  I 
pour  fluid  through  an  opening,  and  my 
image  is  only  the  placing  of  the  funnel 
in  the  opening." — Griininger,  4/III. 

(5)  The    kincssthetic    image    is    ojten 
forced  and  is  superfluous  to  the  under- 
standing of  the  function  of  the  object. 


208 


T.  V.  MOORE  I 


Handbeil:  "I  soon  understood  the 
word,  but  the  simple  consciousness  of 
meaning  was  forced  into  the  background 
of  consciousness  by  the  task.  I  can  ex- 
press this  simple  consciousness  of  mean- 
ing by  the  sentence:  *  I  know  well  what 
that  is ! '  Then  I  asked  myself  under  the 
influence  of  my  task:  'What  purpose  does 
it  serve?'  Then  there  came  to  me  the 
clear  concept  that  it  is  of  use  in  cutting 
wood.  With  this  concept  of  purpose 
were  some  broken,  confused  words.  I  do 
not  know  whether  they  were  German  or 
English.  There  was  also  a  dark  blurred 
image  of  an  island  in  Lake  George,  where 
I  have  often  cut  wood  in  summer." — 
Moore,  i6/VI. 

(6)  The  concept  of  purpose,  though  at 
times  more  or  less  restricted,  never  mis- 
carries entirely. 


Fahne:  It  was  rather  difficult  for  me 
to  connect  a  kinsesthetic  image  with  the 
word.  At  first  I  imaged  a  flag  as  I  saw 
one  recently  waving  on  a  little  tower  in 
Leopold  Street.  But  I  said  to  myself  at 
once,  'This  waving  is  not  a  kinaesthetic 
image.'  Then  I  imaged  to  myself  how  I 
would  place  this  flag  on  the  little  tower. 
That  the  purpose  of  the  flag  is  not  cov- 
ered by  my  motor  image  of  it,  goes 
without  saying." — Lehner,  S/III. 


(6)  The  kinczsthetic  image  is  not  always 
pertinent  to  the  purpose  of  the  object. 

Bohrer:  "Again  the  meaning  first  and 
then  a  visual  image  of  the  object — of  a 
whole  situation.  I  attempted  to  screw 
a  drill  through  the  wall,  and  instead  of 
that  I  lifted  the  whole  wall  with  the 
drill."— Frl.  Marezoll,  9/VII. 


V.   MEANING  AND  THE  WORD 

(a)  Quantitative  Results 

In  the  perception  of  the  meaning  of  words,  subjects  often 
spoke  of  the  meaning  being  associated  with  an  auditory- 
kinsesthetic  verbal  image  of  the  word  itself.  No  attempt  was 
made  to  find  out  by  reaction  time  the  temporal  relations  of 
the  verbal  image  and  meaning  in  the  perception  of  printed 
words.  From  the  introspective  results  no  definite  answer 
can  be  obtained.  The  two  are  so  close  together  that  they 
appear  simultaneous.  One  might,  however,  surmise  that 
since  the  word  must  be  read,  in  order  that  it  may  be  perceived 
and  understood,  verbal  sensations  or  verbal  imagery  are 
likely  to  come  prior  to  understanding. 

On  account  of  the  close  connection  with  the  sensations 
involved  in  reading  and  the  understanding  of  printed  words, 
such  material  presents  no  little  difficulty  in  studying  the 


MEANING  AND  IMAGERY 


209 


necessary  relations  between  verbal  imagery  and  meaning. 
Pictures  seemed  to  offer  a  more  favorable  material  for  study. 
If  meaning  is  the  kinsesthesis  of  speech,  then  the  knowledge 
that  a  picture  before  me  represents  a  tree  should  come  when 
I  name  the  picture  and  not  before.  A  series  of  reaction 
times  for  the  naming  of  pictures  and  perceiving  the  meaning 
of  pictures  should  give  approximately  identical  results. 
Three  of  our  subjects  took  part  in  these  experiments. 

With  all  three  subjects  there  is  strong  evidence  that  in 
general  it  takes  longer  to  react  to  the  word  than  to  the 
meaning.  The  means  for  reaction  to  the  word  are,  in  every 
case,  longer  than  those  for  meaning.  This  excess  is  also 

SUBJECT  LEHNER 
Pictures 


Date 

Word 

T 

V 

Date 

Simple  Meaning 

T 

V 

'  Baum 

845 

214 

Sage 

492 

i 

Uhr 

630 

i 

Katze 

419 

74 

Lilie 

968 

337 

Hahn 

251 

242 

Sichel 

638 

7 

9/III 

Ring 

923 

430 

9/III 

< 

Kafer 
Hammer 

626 

794 

.4 

Eimer 
Krone 

500 
629 

I3l 

Treppe 

601 

30 

Pfau 

416 

77 

Sense 

726 

95 

Hobel 

517 

Kamel 

698 

67 

I9/V 

Spinne 

579 

86 

,  Mitra 

775 

144 

Schlitten 

572 

79 

f  Wiirfel 

840 

209 

Fernglas 

704 

211 

I9/V 

\  Frosch 
[  Pinsel 

649 
689 

18 
58 

26/V 

Haue 

Krug 

718 

536 

225 
43 

26/V 

. 

Apfel 

Uhr 

708 
493 

77 
138 

Stuhl 
Baum 

380 
673 

H3 

1  80 

Wiege 

780 

149 

Uhr 

547 

54 

Katze 

485 

146 

Lilie 

334 

159 

Ring 

720 

89 

Sichel 

383 

no 

Haken 

563 

68 

Hammer 

558 

65 

Sage 

594 

37 

Sense 

349 

144 

Fernglas 

410 

221 

Kamel 

392 

IOI 

20/VH 

. 

Pfau 
Krone 

376 
713 

255 
82 

20/VII 

Kafer 
Pinsel 

460 
468 

33 
25 

Eimer 

375 

256 

Treppe 

327 

166 

Hobel 

598 

33 

Frosch 

411 

82 

Stuhl 

373 

258 

Wiirfel 

400 

93 

Haue 

623 

8 

Wiege 

39i 

102 

Schere 

560 

70 

Apfel 

553 

60 

Krug 

474 

157 

Korb 

344 

149 

Mitra 

572 

79 

29)18,324 

3,392 

30)14,798 

3,350 

631 

117 

Mean     =  493 

112 

Median  =  480 

Number  of  times  median  for  meaning  exceeds  reaction  time  =  6. 


210 


T.  V.  MOORE 


SUBJECT  KULPE 
Pictures 


Date 

Word 

T 

v 

Date 

Simple  Meaning 

T 

V 

Horn 

1,020 

98 

Pferd 

525 

108 

Sofa 

767 

155 

Biirste 

510 

123 

Rechen 

824 

98 

Haus 

798 

165 

Dampsfchiff 

769 

153 

Ente 

308 

325 

Kette 

825 

97 

Fahne 

673 

40 

Zwicker 

738 

184 

Flasche 

967 

334 

9/IH 

Finger 
Stiefel 

843 
1,692 

79 
770 

9/III 

Trichter 
Bohrer 

570 
659 

6l 

26 

Dolch 

837 

85 

Uhr 

524 

109 

Kerze 

1,718 

796 

Lilie 

957 

324 

Lilie 

957 

35 

Hahn 

573 

60 

Sichel 

834 

88 

Kafer 

767 

134 

Haken 

759 

163 

Hammer 

722 

89 

Ring 

332 

590 

Lowe 

327 

306 

14)12,915 

3,39i 

14)8,880 

2,206 

922 

242 

Mean     =633 

157 

Median  =  616 

Number  of  times  median  for  meaning  exceeds  reaction  time  to  word=  I. 

SUBJECT  MAREZOLL 
Pictures 


Date 

Word 

T 

v 

Date 

Simple  Meaning 

T 

V 

Korb 

959 

48 

Zirkel 

998 

34i 

Schere 

825 

86 

Eimer 

643 

H 

Pickel 

1,862 

951 

Stuhl 

463 

194 

26/V 

Apfel 

622 

289 

26/V 

Sichel 

1,009 

352 

Uhr 

78i 

130 

Trommel 

561 

96 

Wiege 

729 

182 

Dampfschiff 

463 

194 

Tasse 

1,175 

264 

Windmuhle 

526 

131 

Maske 

873 

38 

Kirsche 

560 

97 

Lyra 

782 

129 

Zither 

796 

139 

25/VI 

Engel 

•736 

175 

25/VI 

' 

Kette 

739 

82 

Ochs 

671 

240 

Fahne 

50i 

156 

Mitra 

913 

2 

Wurfel 

628 

29 

12)10,928 

2,534 

12)7,887 

1,825 

911 

211 

Mean     =  657 

152 

Median  =  594 

Number  of  times  median  for  meaning  exceeds  reaction  time  for  word  =  o. 

greater  than  the  mean  variation.  With  one  subject  in  29 
reactions  to  words,  only  6  were  shorter  than  the  median 
for  meaning;  with  another,  i  in  14;  with  another,  o  in  12. 

(b)  Introspective  Data 

Turning   to   the   introspective   results   we   find   them   in 
accordance  with  the  quantitative  measurements.     Time  and 


MEANING  AND  IMAGERY 


211 


time  again,  whether  the  task  were  meaning  or  word,  the 
same  sequence  of  events  was  perceived,  viz.,  (i)  meaning, 
(2)  word,  (3)  reaction.  Often,  however,  when  the  task  was 
meaning,  the  word  was  reported  as  coming  during  or  after 
reaction. 

Some  special  points  of  difference  between  the  word  and 
the  meaning  are  given  below. 


(1)  The  meaning  leads  to  the  word — the 
designation  of  the  picture. 

Frosch : "  The  meaning  was  first  present. 
I  felt  a  strong  striving  for  the  word,  as  it 
were  from  various  sides  of  the  drawing. 
The  reaction  followed  after  the  entrance  of 
the  word." — Lehner,  9/V. 

(2)  A  meaning  cannot  be  lacking  if  the 
subject  names  the  picture — no  matter  what 
the  task. 


(3)  The  meaning  is  what  it  is  by  its  own 
right.     It  is  never  said  to  have  a  meaning. 

Pferd:  "Immediately  after  I  saw  the 
picture  I  experienced  a  tone  of  familiarity 
and  knew  what  this  picture  represented. 
At  the  same  time,  with  the  reaction  came 
the  word  'Pferd.'  I  did  not  react  to 
the  word.  The  tone  of  familiarity  was 
related  not  to  the  picture,  but  to  what  it 
signified.  The  picture  was  a  symbol  of 
real  objects  and  its  signification  con- 
sisted herein,  viz. — to  point  to  them." — 
Kiilpe,  9/III. 

(4)  The  meaning  is  sometimes  desig- 
nated by  a  word  which  is  known  to  be  in- 
appropriate. 

Lilie:  "First  I  recognized  in  the  picture 
a  flower,  then  I  named  it  by  mistake 
'Tulpe.'  I  knew  that  'Tulpe'  did  not  fit 
the  picture.  Then  through  the  form  of 
the  flower,  etc.,  I  was  occasioned  to  say 
"Glockenblume."— Lehner,  9/III. 


(i)   The  word  never  leads  to  the  meaning. 


(2)  The  word  may  be  lacking  when  the 
task  is  meaning. 

Eimer:  The  word  did  not  appear  at  all. 
Various  memories  were  in  the  back- 
ground of  consciousness. — Frl.  Marezoll, 
26/V. 

(3)  The  word  may  have  a  special  mean- 
ing of  its  own;  e.  g.,  the  word  has  a  more 
general  meaning  than  that  of  the  picture. 

Engel:  "Immediately  a  memory  image. 
After  this  image  came  the  word.  I  knew 
that  the  meaning  of  the  word  was  more 
general  than  that  of  the  picture." — Frl. 
Marezoll,  25/VI. 


(4)   The  word  is  never  designated  by  a 
meaning. 


212  T.  V.  MOORE 

VI.   INFLUENCE  OF  THE  OBSERVER'S  ATTITUDE 

When  a  short  abstract  of  this  paper  was  read  last  Decem- 
ber at  the  meeting  of  the  Southern  Society  of  Philosophy  and 
Psychology,  it  was  suggested  that  the  difference  in  reaction 
time  to  meaning  and  imagery  is  to  be  explained  by  a  difference 
in  the  attitude  of  the  subject.  He  reacts  quicker  when  told 
to  react  to  meaning,  not  because  the  meaning  is  something 
different  from  the  imagery  but  because  he  himself  assumes 
a  different  attitude. 

This  objection  implies  that  there  is  no  real  difference 
between  meaning  and  imagery,  but  that  when  we  call  them 
by  different  names  the  subject,  for  some  obscure  reason, 
assumes  such  a  different  attitude  that  it  markedly  influences 
his  reaction  time.  The  objector  in  other  words  does  not 
wish  to  admit  a  difference  between  meaning  and  imagery,  and 
refers  the  difference  in  reaction  time  to  an  unexplained  and 
perhaps  inexplicable  mystery. 

To  say  the  least,  this  explanation  is  highly  improbable. 
For  supposing  there  is  no  such  thing  as  a  special  'meaning 
process'  and  that  the  accruing  image  is  identical  with  the 
meaning,  then  the  task  of  the  subject  in  the  two  sets  of 
reactions  is  really  identical.  It  is  simply  called  by  different 
names.  If  that  were  the  case,  then  the  subject  ought  (i)  to 
have  a  real  difficulty  in  distinguishing  his  two  tasks.  (2)  He 
ought  to  give  introspective  reports  identifying  the  two  pro- 
cedures. (3)  The  reaction  times  ought  to  be  identical  within 
the  limits  of  the  probable  error. 

None  of  these  things  were  so,  but  on  the  contrary  (i)  The 
tasks  were  readily  distinguished.  (2)  The  introspective  re- 
ports clearly  separate  the  two  processes.  (3)  The  reaction 
times  are  markedly  different. 

All  this  tends  to  render  highly  improbable,  if  not  impos- 
sible, the  explanation  which  suggested  that  the  difference  in 
the  reaction  times  is  not  to  be  explained  by  a  real  difference 
in  the  tasks,  dependent  on  a  difference  between  meaning  and 
imagery,  but  is  due  entirely  to  the  difference  in  the  attitude 
of  the  subject.  In  fact,  it  is  very  hard  even  to  imagine  a 


MEANING  AND  IMAGERY  213 

mental  mechanism  which  would  produce  two  separate  atti- 
tudes with  such  different  effects  in  the  reaction-times,  if 
that  to  which  the  subject  takes  an  attitude  is  in  both  cases 
merely  one  and  the  same  thing  that  the  experimenter  calls 
by  a  different  name. 

Let  us,  however,  go  a  step  further.  Our  subjects  reacted 
to  visual  and  kinsesthetic  images.  If  we  wish  to  compare  the 
reaction  times  in  this  case  we  will  find  them  markedly  dif- 
ferent. Is  it  possible  to  explain  that  difference  by  a  difference 
in  the  attitude  of  the  subject? 

If  we  should  argue  visual  imagery  is  distinct  from  kin- 
aesthetic  (i)  because  the  subject  distinguishes  two  different 
tasks  when  told  to  react  to  the  one  or  the  other;  (2)  because 
the  introspective  reports  clearly  separate  the  one  from  the 
other;  (3)  because  the  reaction  times  to  visual  imagery  are 
much  shorter  than  to  kinsesthetic  imagery,  no  one  would 
doubt  the  validity  of  the  argument.  When,  however,  the 
same  argument  is  made  in  regard  to  imagery  and  meaning,  it 
is  called  in  question  and  the  attempt  is  made  to  explain  away 
the  difference  by  ascribing  it  to  a  difference  in  the  attitude  of 
the  subject.  If,  however,  the  difference  in  the  attitude  of  the 
subject  is  not  the  real  explanation  in  the  latter  case,  but  a 
real  difference  between  visual  and  kinsesthetic  imagery,  then 
this  difference  in  the  attitude  of  the  subject  cannot,  without 
any  more  ado,  explain  the  shorter  reaction  time  for  meaning 
as  compared  with  imagery. 

Furthermore,  the  difference  in  attitude  itself  must  be 
explained.  Granted  that  there  is  a  difference  in  attitude, 
what  is  the  most  likely  explanation  for  the  fact?  The  first 
thing  that  comes  to  mind  is  that  in  the  two  sets  of  conditions 
the  subject  is  taking  an  attitude  to  two  different  things.  If 
that  is  the  case  then,  meaning  and  imagery  must  be  dis- 
tinguished. But  how  distinguished — as  two  different  mental 
processes  or  as  two  aspects  of  one  and  the  same  process? 

In  the  sequence  of  events  that  follow  the  exposition  of  the 
stimulus  word,  there  may  be,  if  you  wait  long  enough,  not 
only  visual  but  also  kinsesthetic  imagery.  Are  these  aspects 
of  one  and  the  same  mental  processes,  or  specifically  dif- 


214  T.  V.  MOORE 

ferent  items  in  a  definite  series  of  events?  Reasons  have 
already  been  given  for  distinguishing  them.  These  reasons 
point  to  events  that  are  qualitatively  distinct,  and  the 
distinction  can  scarcely  be  called  in  question.  But  the  very 
same  reasons  point  to  meaning  as  qualitatively  distinct  from 
imagery.  When,  furthermore,  one  considers  the  fact  that  in 
the  understanding  of  words  the  meaning  process  is  never 
absent,  but  that  visual  and  kinaesthetic  imagery  may  both 
be  lacking,  there  is  an  added  reason  why  meaning  should  not 
be  identified  with  an  aspect  of  visual  or  kinsesthetic  imagery. 

Furthermore,  a  difference  in  the  attitude  of  the  observer 
cannot  be  made  the  sole  reason  for  the  difference  in  the  re- 
action times. 

(i)  In  the  set  of  experiments  referred  to  in  the  beginning, 
the  subject's  task  was  to  observe  and  remember  a  series  of 
words,  pictures  or  objects.  Nothing  was  said  about  attending 
to  meaning  or  imagery.  He  had  simply  to  report  what  he 
had  experienced — whatever  that  might  be.  Here  the  ques- 
tion of  a  difference  in  the  "set"  of  the  observer  does  not  enter 
at  all.  In  these  experiments,  the  subjects  reported  that  in 
the  perception  of  words,  meaning  preceded  imagery.  This 
suggested  the  problem  of  an  objective  test  of  the  accuracy  of 
the  introspection.  The  reaction  time  experiments  followed, 
and  confirmed  with  entire  satisfaction  the  introspections  of 
the  earlier  series. 

(ii)  In  the  reaction  time  experiments  no  matter  what  the 
task — whether  the  subject  is  in  the  meaning  attitude  or  the 
image  attitude,  he  regularly  reports  meaning  as  coming 
prior  to  imagery.  If  the  difference  in  the  £  set'  of  the  observer 
were  the  sole  reason  for  the  difference  in  reaction  time,  we 
should  not  expect  that  no  matter  what  his  'set'  he  would 
nevertheless  observe  a  rather  constant  temporal  relation 
between  meaning  and  imagery. 

The  introspective  results  and  the  reaction  times  are  supple- 
mentary. When  taken  together  they  leave  no  doubt  that 
we  have  really  been  investigating  the  temporal  relation  of 
meaning  and  imagery. 


MEANING  AND  I M ACER  Y  215 

VII.   THE  CONTEXT  THEORY  OF  MEANING  AND  THE  TEM- 
PORAL RELATIONS  OF  MEANING  AND  IMAGERY 

It  may  now  be  asked:  Whom  does  all  this  concern? 
Who  maintains  that  imagery  is  meaning?  In  spite  of  a 
certain  modification  of  the  image  theory  of  meaning,  Pro- 
fessor Titchener's  context  theory  cannot  account  for  the 
experimental  facts  brought  out  in  his  own  and  other  labora- 
tories. From  an  analysis  of  his  theory  it  is  apparent  that  he 
maintains  that  meaning  is  often  identical  with  imagery.  In 
fact  under  the  conditions  of  our  experiments  the  images  and 
words  that  followed  upon  the  sensations  of  the  stimulus  words 
and  pictures  were  actually  the  context.  Analogous  conscious 
states  have  been  reported  by  Cornell  observers  as  the  meaning 
under  somewhat  similar  conditions.  But  they  did  not  take 
into  consideration  the  temporal  relations  of  meaning  and 
imagery. 

A  brief  analysis  of  the  context  theory  of  meaning  will  show 
how  intimately  it  is  concerned  with  the  temporal  relations 
of  meaning  and  imagery. 

(a)  Outline  of  the  Theory 

"  Meaning,  psychologically,  is  always  context."1  Such  is 
the  definition  that  Professor  Titchener  gives  to  a  fact  of 
consciousness  with  which  the  modern  psychology  of  thought 
is  now  interested. 

What  is  context?  Context  in  English  is  a  word  used  to 
signify  the  setting  of  a  sentence  or  a  quotation — its  relation 
to  what  the  author  has  written  before  and  after  the  passage  in 
question.  Titchener  lays  particular  stress  upon  what  comes 
after  in  the  definition  of  psychological  context.  "Context, 
in  this  sense,  is  simply  the  mental  process  which  accrues  to 
the  given  process  through  the  situation  in  which  the  organism 
finds  itself."  A  sensation  by  itself  has  no  meaning — neither 
has  an  image.  When  a  second  mental  process  accrues  to  a 
former  one — this  second  mental  process  is  the  meaning  of  the 
first  one.  It  does  not  produce  a  new  something  called  mean- 

1  'A  Text  Book  of  Psychology,'  New  York,  1911,  p.  367. 


216  T.V.  MOORE 

ing,  it  is  the  meaning.     "One  mental  process  is  the  meaning 
of  another  mental  process  if  it  is  in  that  other's  context."2 

What  are  the  mental  processes  that  accrue  to  others 
and  thus  constitute  their  meaning?  Originally  the  secondary 
process  which  constituted  the  meaning  was  a  group  of  sensa- 
tions coming  from  a  bodily  attitude  of  the  organism.  If 
the  animal  took  an  attitude  of  defence  the  kinaesthetic  sensa- 
tions thus  aroused  did  not  exactly  mean — did  not  signify  that 
something  to  be  feared  was  at  hand.  The  whole  complex  of 
sensations  involved  constituted  the  meaning  "something  to 
be  feared." 

At  the  present  day,  however,  the  human  mind  has  passed 
beyond  the  elementary  stage  of  the  primitive  organism.  The 
essential  difference  between  present  human  intelligence  and 
its  early  prototype  consists  in  the  use  of  imagery  as  well  as 
sensations  for  the  constituents  of  meaning.  "Image  has 
now  intervened  upon  sensation  and  meaning  can  be  carried 
in  imaginal  terms."2  Thus  spoken  and  written  language  has 
become  possible.  A  sensation  arouses  an  image  and  the 
image — the  psychological  process  accruing  to  the  sensations — 
is  the  meaning  of  the  sensation. 

Various  types  of  mind  exist.  Each  has  a  special  tendency 
to  form  some  kind  of  imagery  in  understanding  sensations. 
Indeed  "If  we  were  to  make  serious  work-  of  a  differential 
psychology  of  meaning,  we  should  probably  find  that  in  the 
multitudinous  variety  of  situations  and  contexts,  any  mental 
process  may  possibly  be  the  meaning  of  any  other."3 

It  is  Professor  Titchener's  opinion  however  that  of  all 
the  possible  types  of  supplementary  mental  processes,  two 
are  of  special  importance:  kinsesthesis  and  verbal  images. 
Indeed  he  pushes  the  verbal  theory  so  far  as  to  say:  "The 
words  that  we  read  are  both  perception  and  context  of  per- 
ception, the  auditory  kinsesthetic  idea  is  the  meaning  of  the 
visual  symbols."4 

1  Op.  cit.,  p.  367. 

2  Op.  cit.,  p.  367. 

3  'Lectures  on  the  Experimental  Psychology  of  the  Thought  Processes/  1909,  p. 
178. 

4  'A  Text-Book  of  Psychology,'  p.  368. 


MEANING  AND  IMAGERY  217 

Thus  far,  Professor  Titchener's  theory  is  entirely  psycho- 
logical. But  in  order  to  meet  all  possible  contingencies 
arising  from  introspections  that  he  or  others  may  report, 
where  meaning  shows  no  trace  of  a  sensory  conscious  element 
—a  physiological  factor  is  introduced. 

Meaning  is  not  always  conscious;  i.  e.,  the  imaginal 
supplement  to  the  sensation  is  not  always  to  be  found  even 
by  the  most  careful  introspection.  In  such  cases  the  sensory 
supplement  exists — it  is  a  physiological  process  in  the  nervous 
system. 

Professor  Titchener  thus  summarizes  his  theory  of  per- 
ception: 

"Our  account  of  the  psychology  of  perception  is  now,  in 
the  author's  view,  complete.  It  has  embraced  four  principal 
points : 

"First,  under  the  general  laws  of  attention  and  the  special 
laws  of  sensory  connection,  sensations  are  welded  together, 
consolidated,  incorporated  into  a  group. 

"Secondly,  this  group  of  sensations  is  supplemented  by 
images. 

"Thirdly,  the  supplemental  group  has  a  fringe,  a  back- 
ground, a  context;  and  this  context  is  the  psychological 
equivalent  of  its  logical  meaning. 

"Fourthly,  meaning  may  lapse  from  consciousness  and 
conscious  context  may  be  replaced  by  a  non-conscious  nerv- 
ous set."1 

The  type  of  meaning  in  the  third  caption  is  decidedly 
different  from  that  given  a  few  pages  previous.  There 
meaning  is  context — context  is  the  mental  process  that 
follows  upon  and  accrues  to  another  mental  process.  The 
examples  given  are  the  images  spoken  of  in  the  second  caption. 
Here  we  suddenly  find  that  meaning  does  not  lie  in  the  adven- 
ing images — but  in  their  fringes. 

To  harmonize  this  new  idea  with  what  has  gone  before 
we  may  suppose  that  if  meaning  is  conscious  (in  the  sense  of 
being  conscious  described  by  Titchener)  it  is  given  by  the 
context  which  may  be  (a)  a  second  group  of  sensations,  (b) 

1  'A  Text  Book  of  Psychology,'  1911,  p.  371. 


2i8  T.  V.  MOORE 

an  image  or  a  group  of  images,  (c)  the  fringe  or  background  of 
such  images — the  fringe  itself  being  always  understood  as 
some  kind  of  sensory  element  or  elements,  (d)  various  com- 
binations of  (a),  (b)  and  (c). 

(b)    The  Evidence  for  the  Theory 

In  the  interests  of  simplicity  we  may  leave  aside  the 
speculations  about  meaning  in  the  primitive  organism  and 
confine  ourselves  to  the  explanation  of  the  fact  of  meaning 
as  we  experience  it. 

On  what  then,  may  we  ask,  is  the  statement  based  that 
meaning  is  context — that  it  is  a  '  sensory  complex  $,  following 
upon  sensation  or  image  A?  The  points  of  evidence  are: 

1.  Introspection  shows  that  when  a  word  or  a  sentence  is 
understood  and  careful  search  is  made  we  always  find  some 
kind  of  imagery — verbal,  kinsesthetic,  visual,  etc. 

Granted  that  this  is  so  what  does  it  prove?  Nothing  more 
than  this.  In  the  complex  of  mental  processes  called  up  by 
the  task  of  understanding  a  word  or  sentence  imagery  is 
present.  It  does  not  show  that  this  imagery  is  the  meaning 
— which  is  the  very  point  in  question. 

Titchener  says:  "The  meaning  of  the  printed  page  may 
now  consist  in  the  auditory-kinsesthetic  accompaniment  of 
internal  speech;  the  word  is  the  word's  own  meaning."1 

He  then  refers  in  a  note  to  introspections  in  the  studies 
of  Watt  and  of  Messer  which  speaks  of  meaning  being  simul- 
taneous with  auditory-kinaesthetic  imagery.  But  such  a 
citation  is  not  to  the  point.  The  fact  that  one  thing  accom- 
panies another  is  certainly  no  evidence  that  the  two  are 
identical. 

2.  Analysis  shows  no  evidence  of  'imageless  thoughts.' 
What    analysis    shows    is    the    fact   of    meaning.     Many 

observers  have  maintained  that  in  their  consciousness  of 
meaning  sensational  elements  are  lacking.  Professor  Titch- 
ener in  his  analysis  finds  also  the  fact  of  meaning  and  giving 
to  the  students  in  his  laboratory  the  task  of  reporting  every 
mental  process  that  they  can  observe,  he  obtains  experiences 

1  'Lectures  on  the  Experimental  Psychology  of  the  Thought  Process/  p.  177. 


MEANING  AND  IMAGERY  219 

far  richer  in  sensational  elements  than  are  elsewhere  found. 
Given  the  task,  'find  imagery,'  and  it  will  certainly  come. 
And  if  the  subject  be  told  to  look  for  imageless  imagery,  it 
will  not  be  found.  Meaning  and  imagery  however,  have 
been  found  both  by  Professor  Titchener  and  a  number  of 
other  observers.  Facts  are  common  property.  It  remains 
for  Professor  Titchener  to  prove  that  meaning  is  identical 
with  the  concomitant  or  subsequent  imagery.  This  he  has 
not  done. 

The  context  theory  of  imagery  demands  imagery,  when 
meaning  is  present.  If  meaning  equals  imagery,  imagery 
equals  imagery.  No  imagery — no  meaning,  must  be  the 
conclusion  to  be  drawn  from  this  theory.  Nevertheless 
Professor  Titchener  shrinks  from  admitting  all  that  is  involved 
in  his  doctrine.  Why?  Because  he  himself  has  observed 
that  there  are  times  when  he  experiences  meaning  and  is  not 
conscious  of  imagery.  He  himself,  therefore,  in  spite  of  the 
ease  with  which  he  images  things  and  situations,  has  experi- 
enced the  very  state  of  mind  the  existence  of  which  he  denies. 

"In  rapid  reading,  the  skimming  of  pages  in  quick  succes- 
sion; in  the  rendering  of  a  musical  composition,  without 
hesitation  or  reflection,  in  a  particular  key;  in  shifting  from 
one  language  to  another  as  you  turn  to  your  right  or  left- 
hand  neighbor  at  a  dinner  table:  in  these  and  similar  cases, 
meaning  has  time  and  time  again,  no  discoverable  representa- 
tion in  consciousness."1  No  discoverable  representation  in 
consciousness  means  no  sensational  element — no  sensational 
or  imaginal  complex. 

What  is  Professor  Titchener's  explanation  of  such  "image- 
less  thoughts"  that  come  to  him  as  he  skims  over  the  pages 
of  a  book?  He  has  found  "imageless  thoughts,"  what  then 
is  to  be  done  with  them?  Explain  them  away  and  then  deny 
their  existence.  How  explain  them  away?  Refer  them  to 
the  nervous  system?  Meaning  here  is  not  imagery  for  no 
imagery  is  present.  What  is  it  then?  A  physiological  proc- 
ess, without  any  conscious  accompaniment.  Why  without 
any  conscious  accompaniment?  Because  by  hypothesis  the 

1  'A  Text-Book  of  Psychology,'  p.  369. 


220  TV  V.  MOORE 

only  conscious  processes  that  come  into  consideration   are 
sensations  and  these  are  lacking. 

On  the  one  hand,  we  have  an  hypothesis;  on  the  other, 
a  fact — the  imageless  consciousness  of  meaning  (imageless 
thoughts)  in  rapid  reading.  The  fact  cannot  be  accounted 
for  by  the  hypothesis;  therefore  Professor  Titchener  denies 
the  fact.  My  consciousness  of  meaning  is  unconscious.  I  do 
not  think  but  my  nervous  system  is  thinking  for  me. 

The  reference  of  imageless  thought  to  an  unconscious 
physiological  process  in  the  nervous  system  brings  us  to  a 
third  point  in  the  evidence  for  Professor  Titchener's  theory. 

(3)  "Our  psychology  is  to  be  explanatory  and  our  explana- 
tions are  to  be  physiological."1 

Adherence  to  this  principle  and  the  ruling  out  of  facts 
that  it  cannot  explain,  give  to  Professor  Titchener's  theory  a 
certain  plausibility. 

What  can  be  referred  to  the  nervous  system  is  explained 
What  cannot  be  referred  to  the  nervous  system  is  not  ex- 
plained. It  is  in  fact  inexplicable.  There  must  be  a  mistake 
in  the  observation.  It  must  be  explained  away.  The  ner- 
vous system  with  its  sense  organs  and  its  centres,  can  appar- 
ently take  care  of  sensations  and  images.  It  gives  us  the 
sensational  elements  of  our  conscious  life  and  apparently 
excludes  anything  like  imageless  thinking.  If  then  we  are 
to  explain  ' imageless  thought'  we  must  analyze  it  in  terms 
of  the  elements  given  by  the  nervous  system,  or  else  explain 
it  away  altogether. 

Such  a  procedure,  however,  places  empirical  psychology 
not  only  under  the  dominion  of  metaphysics,  but  subjects  it 
to  one  particular  metaphysical  theory.  Under  such  condi- 
tions an  impartial  empirical  study  of  the  mind  becomes 
impossible.  Let  us  first  study  the  facts  of  consciousness  and 
then  build  up  our  metaphysical  theories. 

Professor  Titchener  is  right  in  demanding  that  the  science 
of  psychology  should  be  explanatory;  he  is  wrong  in  main- 
taining that  everything  must  be  explained  in  consonance 
with  a  particular  metaphysical  theory. 

1  'A  Text-Book  of  Psychology,'  p.  370. 


MEANING  AND  IMAGERY  221 

As  a  matter  of  fact  neither  Professor  Titchener  nor  anyone 
else  knows  the  limitations  nor  the  possibilities  of  the  nervous 
system.  Nor  does  anyone  know,  for  that  matter,  what  the 
nervous  system  may  be  called  upon  to  do  if  it  is  to  explain 
the  facts  of  our  conscious  life.  We  do  not  know  all  about  the 
facts  of  consciousness  and  until  we  do,  explanatory  psychology 
must  be  careful.  We  do  not  know  all  about  the  nervous 
system  and  it  is  not  wise  to  distort  the  fact  of  consciousness 
to  fit  the  narrow  outlines  of  our  present  horizon. 

Let  us  first  investigate  the  facts  of  consciousness  without 
any  timidity  about  their  ultimate  explanation.  Let  us  first 
find  out  what  we  have  to  explain,  and  then  explain  it. 

The  context  theory  of  meaning  is  not  based  entirely  upon 
such  general  considerations  as  we  have  picked  out  from 
Professor  Titchener's  writings.  There  are  a  number  of 
experimental  studies  that  have  been  put  forward  as  tests  in 
confirmation  of  the  theory. 

Of  these,  we  may  analyze  two,  leaving  a  more  complete 
account  of  the  literature  to  a  full  report  of  our  experiments 
which  we  hope  to  publish  later. 

Helen  Clarke,1  in  an  article  on  '  Conscious  Attitudes '  took 
up  the  problem  of  the  understanding  of  words  and  sentences. 
She  confirmed  the  reports  of  other  observers  that  '  often  the 
images  are  adequate,  irrelevant  or  even  contradictory'  (p.  241). 
The  inadequacy  she  explained  by  saying  that  'we  have  no 
criterion  save  the  facts  themselves,  by  which  we  can  decide 
how  clear  or  complete  an  image  must  be  in  order  to  carry  a 
meaning'  (p.  241).  The  contradictory  character  she  ac- 
counted for  by  pointing  out  that  in  every  one  of  her  cases 
there  was  '  sufficient  connection  between  the  logical  meaning 
of  the  word,  and  the  psychological  context  of  the  act  of 
understanding,  for  the  latter  to  carry  a  general  meaning' 
(p.  242).  The  fact  of  irrelevancy,  she  said,  was  less  easy 
to  explain. 

Miss  Clarke  therefore  seems  to  be  conscious  of  the  fact 
that  words  have  a  logical  meaning  which  cannot  be  identified 
with  the  imagery  that  they  evolve.  She  distinguishes  be- 

1  Am.  J.  of  Psycho!.,  XXII.,  pp.  214-249. 


222  T.  V.  MOORE 

tween  the  word — the  imagery  that  it  evolves — and  the 
meaning  that  is  carried.  She  finds  also  that  imagery  is  often 
irrelevant.  Irrelevant  to  what,  we  may  ask?  To  the  mean- 
ing. She  therefore  realizes  a  difference  between  the  psycho- 
logical process  called  an  image  and  another  something  of 
which  she  is  also  conscious  and  which  may  be  termed  the 
meaning  of  the  word.  Miss  Clarke1  seems  to  look  upon 
general  meaning  as  a  logical  something  of  which  no  account 
need  be  taken  in  psychology.  If,  however,  the  task  of  psychol- 
ogy is  to  investigate  all  conscious  processes,  logical  meaning 
cannot  be  ruled  out  as  'outside  the  sphere  of  psychology.'2 
For  "logical  meaning"  is  conscious.  Its  nature  is  therefore 
a  psychological  problem.  It  is  that  something  to  which  the 
imagery  is  often  inadequate,  irrelevant  and  contradictory. 
Miss  Clarke  has  implicitly  at  least  recognized  it  as  a  conscious 
state,  distinct  from  imagery. 

Edmund  Jacobson3  investigated  by  the  Method  of  Intro- 
spection (i)  The  Perception  of  Letters,  (2)  The  Meaning  of 
Words,  (3)  The  Understanding  of  Sentences.  The  instructions 
to  his  subjects  (three  observers)  were  as  follows: 

I.  Give  a  minute  account  of  all  the  mental  processes  you 
experience  in  their  temporal  order  of  sequence. 

II.  Put  direct  description  of  conscious  processes  outside 
of  parentheses,  and  statements  concerning  meanings,  objects, 
stimuli  and  physiological  occurrences  inside. 

The  experiments  on  the  perception  of  letters  showed  that 
under  the  instructions  given  their  meaning  is  usually  accom- 
panied by  the  arousal  of  what  Jacobson  termed  designatory 
processes,  viz.,  kinaesthetic  or  auditory  sensations  or  both. 
Jacobson  calls  attention  to  the  fact  that  "The  main  point 
to  note  is  that  the  precise  statement  of  meaning  is  by  no 
means  easy."  Nor  does  he  state  anything  more  definite  as 
to  what  the  meaning  of  a  letter  is. 

The  experiments  with  the  meaning  of  the  words  were  made 
as  follows:  "A  written  word,  was  laid  before  the  observer  for 
a  period  of  one  minute.  He  was  instructed  to  fixate  the 

1  Along  with  Geissler,  Am.  J.  of  Psychol.,  XXIIL,  p.  194. 

2  Cf.  Geissler,  /.  c. 

3  Am.  J.  of  Psychol.,  1911,  XXII. ,  pp.  553-577. 


MEANING  AND  IMAGERY  223 

word,  to  utter  it  with  quick  repetition  and  to  get  at  its  mean- 
ing. The  concluding  ten  seconds  were  marked  off  by  signals; 
and  the  observer's  task  was  to  report  what  occurred  in  con- 
sciousness during  the  particular  interval. 9\  The  observer  re- 
ported two  kinds  of  imagery:  (a)  That  which  appeared  as  the 
carrier  of  the  meaning  and  (b)  that  which  appeared  as  irrele- 
vant. No  logical  or  psychological  test  could  be  found  to 
distinguish  between  the  relevant  and  irrelevant  imagery. 

The  conclusion  of  Jacobson  was  "that  the  conscious 
meanings  brought  out  in  these  experiments  are  not  perfect 
and  static  logical  meanings  of  definition.  .  .  .  Logically,  the 
representation  of  meaning  is  inadequate;  psychologically,  it 
is  adequate  to  the  demands  of  the  occasion"  (pp.  568-569). 

In  his  experiments  on  the  meaning  of  sentences,  Jacobson 
found  cases  in  which  (i)  an  automatic  reading  was  followed 
by  a  perception  of  the  meaning  identified  with  images  called 
forth  by  the  experiment.  (2)  Cases  in  which  the  mean- 
ing did  not  come  to  the  subject  at  all  in  spite  of  a  wealth 
of  visual,  organic,  kinsesthetic  and  tactual  sensationsl  (3) 
Cases  in  which  the  visual  and  auditory  images  and  sensations 
from  reading  were  the  sole  processes  present  in  consciousness 
— and  yet  the  sentence  had  meaning.  Jacobson  concludes: 
(i)  "Wherever  there  is  meaning  there  are  also  processes," 
i.  £.,  sensations  and  images  of  one  kind  or  another.  (2)  "The 
correlated  meanings  and  processes  are  two  renderings  from 
different  points  of  view  of  the  same  experience." 

The  first  conclusion  seems  established  by  the  introspective 
reports,  but  it  holds  only  for  the  conditions  of  these  experi- 
ments where  ample  time  is  given  for  images  to  appear  and 
the  task  is  set  to  report  primarily  mental  processes,  i.  e., 
sensations  and  images;  and  secondarily,  in  parentheses,  to 
note  meaning  as  it  arises. 

The  second  conclusion:  (which  is  really  the  "crux"  of  the 
whole  situation)  meaning  is  an  aspect  of  sensation  and  imagery, 
is  simply  stated  and  the  reader  is  left  to  judge  for  himself 
on  what  evidence  the  conclusion  is  based.  The  only  evidence 
in  his  paper  for  such  an  indentification  is  to  be  sought  in  the 
fact  that  his  subjects,  as  a  rule,  were  not  satisfied  that  they 


224  T.  V.  MOORE 

had  anything  that  corresponded  with  their  idea  of  meaning 
till  relevant  imagery  was  present.  This  simply  shows  that 
meaning  in  the  Cornell  sense  is  not  present  till  such  imagery 
arises.  From  Jacobson's  own  data,  it  appears,  however, 
that  meaning  in  a  broader  sense  must  have  been  present 
when  meaning  in  the  Cornell  sense  was  denied.  When  Dr. 
Geissler,  instructor  in  psychology  at  Cornell,  for  3  seconds, 
looked  at  the  sentence,  "Did  you  see  him  kill  the  man?," 
and  then  declared  at  the  end  "No  meaning  all  the  way 
through,"  we  can  only  conclude  that  "meaning"  must  have 
been  taken  in  a  very  restricted  sense.  When  again  he  looked 
at  the  sentence,  "The  iron  cube  fell  heavily  on  the  floor," 
reads  it  as  so  many  meaningless  words,  and  then  on  rereading 
obtains  the  meaning,  a  very  loud  sound,  the  time  of  the 
whole  procedure  being  4.5  seconds,  the  conclusion  is  strength- 
ened that  during  the  experiment,  he  was  seeking  for  a  meaning 
in  the  sense  of  an  imaginal  representation.  In  this  sense,  and 
in  no  other,  is  Jacobson's  conclusion  warranted.  An  imaginal 
representation  is  some  kind  of  imagery.  The  sweeping  con- 
clusion that  meaning  is  an  aspect  of  imagery  requires  the 
proof  of  another  proposition,  namely  that  all  meaning 
consists  in  imaginal  representation. 

The  data  of  this  piece  of  introspective  work  is  incom- 
patible neither  with  the  data  nor  the  conclusions  of  the 
Kiilpean  school.  Indeed  it  has  confirmed  the  fact  that  the 
meaning  of  a  sentence  may  be  present  when  the  sole  proc- 
esses present  in  consciousness  are  the  visual  and  auditory 
images  and  sensations  from  reading.  And  if  it  be  true  that 
on  certain  occasions,  as  in  Geissler's  case,  these  same  processes 
were  present  and  the  meaning  was  really  absent,  one  should 
conclude  that  they  cannot  be  identical  with  the  meaning. 
In  like  manner,  a  physician  refuses  to  admit  that  a  definite 
microorganism  is  the  cause  of  a  disease — if  at  times  it  is 
found  when  the  disease  does  not  occur,  and  the  disease 
occurs  when  the  organism  is  absent.  Jacobson  should  there- 
fore have  admitted  that  there  are  times  at  least  when  meaning 
is  not  a  mere  aspect  of  sensations  and  images. 

Professor  Titchener  looks  upon  the  chief  value  of  Jacob- 


MEANING  AND  IMAGERY  225 

son's  work  in  making  the  distinctions  between  the  mere 
statement  that  meaning  is  present  and  the  analytic  descrip- 
tion of  the  psychological  part  of  meaning.  He  says  that 
"He  finds  no  specific  ' meaning  process'  underlying  the 
statement  of  meaning."1 

True  it  is  that  Jacobson  found  no  special  sensory  or 
imaginal  process  as  the  habitual  carrier  of  meanings,  but  he 
did  not  prove  that  meaning  is  not  itself  a  conscious  process. 
In  fact,  his  experiments  seem  rather  to  confirm  the  conclusion 
that  meaning  is  not  imagery,  but  something  else  altogether. 

Had  the  Cornell  School  taken  cognizance  of  the  temporal 
relations  of  meaning  and  imagery,  the  context  theory  of 
meaning  would  have  been  profoundly  modified.  Imaginal 
terms  may  accrue  to  incoming  sensations  and  constitute  by 
definition  their  context.  Do  they  constitute  their  meaning? 
A  determination  of  the  temporal  relation  that  imagery  bears 
to  meaning  shows  that  this  is  impossible.  What  comes  after 
another  cannot  be  said  to  cause,  or  constitute  it,  or  be  identical 
with  it.  Meaning,  therefore,  is  not  context.  What  is  it — 
a  mere  negation?  Not  at  all.  It  is  a  definite  mental  process 
sui  generis.  What  are  its  qualitative  characters?  Some  of 
these  have  been  already  indicated.  A  further  development 
of  the  concept  will  be  given  with  the  fuller  account  of  these 
investigations. 

1 "  Description  vs.  Statement  of  Meaning,"  Am.  J.  o/PsychoL,  1912,  XXIIL,  p.  182. 


THE    SHORTEST    PERCEPTIBLE   TIME-INTERVAL 
BETWEEN  TWO   FLASHES  OF  LIGHT1 

BY  KNIGHT  DUNLAP 

The  Johns  Hopkins  University 

The  determination  of  the  minimal  perceptible  time-inter- 
val: the  shortest  interval  between  two  stimuli  which  allows 
the  stimuli  to  be  perceived  as  .successive,  and  not  simultan- 
eous is  important  for  many  lines  of  work,  including  problems 
of  time-perception  and  rhythm  and  also  problems  of  rate- 
perception.  Moreover  an  important  theory  of  psychic  syn- 
thesis has  been  supported  by  interpretations  of  certain 
measurements  of  the  time-threshold  for  disparate  stimula- 
tions (i.  e.,  stimulations  of  two  modes  of  sense  in  succession). 

My  interest  in  these  several  lines  of  research,  and  also  in 
certain  purely  visual  phenomena,  led  me  to  commence,  in  the 
summer  of  1912,  an  investigation  of  the  time-threshold  for 
visual  stimulation,  and  its  relation  to  the  ' critical  frequency' 
of  flicker  and  fusion.  The  result  of  that  summer's  work 
(done  at  the  Johns  Hopkins  University,  with  myself  as 
principal  observer),  encouraged  me  to  attempt  further  work 
on  the  problem  with  better  apparatus.  During  the  next 
college  year  (1913-1914)  a  graduate  student  was  allowed  to 
take  up  the  problem,  and  obtained  some  results  which  seemed 
important.2  This  student,  on  leaving  the  University,  took 
his  unelaborated  results  with  him,  and  I  have  not  since  been 
able  to  obtain  them.  Last  summer,  having  the  opportunity 
to  work  in  Dr.  Hyde's  laboratory,  I  took  up  the  problem 
again  with  specially  constructed  apparatus  and  obtained 
results  which  are  interesting  and  important.  I  shall  give  in 
the  following  paper  the  results  of  both  of  my  experiments. 

1  From  the  Nela  Research  Laboratory,  National  Lamp  Works  of  the  General 
Electric  Company. 

2  This  work  was  done  with  a  pendulum  apparatus,  giving  great  accuracy,  and  having 
other  advantages  over  the  rotation  apparatus  first  used;  but  with  some  difficulties  of 
manipulation. 

226 


PERCEPTION  OF  TIME-INTERVALS  227 


The  first  work  on  the  visual  time-threshold  was  done  by 
Exner,1  who  worked  with  electric  sparks,  and  found  thresholds 
of  44  cr  at  280  mm.  distance,  and  21  a  at  640  mm.  Weyer,2 
in  Wundt's  laboratory,  found  a  much  lower  threshold,  12  a. 
Weyer  also  found,  using  electric  sparks,  a  flicker-threshold 
from  25  a  to  87  <r,  according  to  the  adaptation  and  other 
conditions,  and  a  threshold  for  separation  of  a  series  from 
42  o-  to  105  cr. 

Shortly  before  my  work  'was  begun  Bassler3  published  the 
results  of  some  of  his  investigations,  in  which  he  found  the 
time-threshold  (length  of  shortest  perceptible  dark  interval) 
to  be  about  40  a  with  two  visual  stimulations,  and  the  flicker 
point  to  be  about  one  third  as  much  (for  serial  stimulation). 

None  of  these  results  are  very  significant,  the  work  with 
electric  sparks  suffering  from  lack  of  control,  and  Bassler's 
being  affected  by  serious  defects  of  method. 

Bassler  used  black  discs  on  which  were  either  two  white 
sectors  or  a  regularly  spaced  series,  and  rotated  the  disc  close 
behind  a  screen  in  which  was  a  hole  a  centimeter  and  a  half 
in  diameter.  This  hole,  in  which  the  alternation  of  black 
and  white  occurred,  was  observed  from  an  unspecified  dis- 
tance. A  student  in  our  laboratory  reproduced  Bassler's 
apparatus,  as  nearly  as  Bassler's  description  allowed,  and 
we  found  that  eye  movement  was  a  very  important  factor  in 
the  observation,  the  eye  movement  being  induced  or  increased 
by  the  motion  of  the  black  and  white  edges  as  they  traveled 
across  the  aperture. 

PRELIMINARY  WORK* 

It  is  obvious  that  the  proper  attack  on  the  problem  of  the 
visual  time-threshold  involves  control  of  the  intensity  and  the 
duration  of  the  flashes  of  light,  and  of  the  adaptation  and 
movement  of  the  eye,  as  well  as  of  the  areas  stimulated. 

In  my  first  experiment  I  succeeded  in  eliminating  the  most 

1  Exner,  Pfliiger's  Archiv,  XI.,  S.  407. 

2  Weyer,  Philos.  Studien,  XV.,  S.  67-138. 

3  Bassler,  Pflugtfs  Archiv,  1911,  Bd.  43,  245-251. 

4  This  work  was  reported  before  the  Natural  Academy  of  Sciences,  November  19, 
1913.     See  abstract  in  Science,  1913,  Vol.  38,  p.  699. 


228  KNIGHT  DUNLAP 

serious  important  cause  of  eye  movement,  namely  the  travel- 
ing of  the  illumination  across  the  area  of  stimulation,  and 
kept  the  illumination  constant  and  the  eye  dark-adapted. 
The  first  factor  which  I  wished  to  investigate  was  the  effect 
of  the  duration  of  the  flashes,  and  the  second  was  the  effect 
of  the  intensity. 

For  simplicity's  sake  I  adopted  the  method  of  rotating 
sectors,  measuring  the  time  interval  by  determining  the 
speed  of  rotation,  and  computing  from  the  angular  width  of 
the  sectors.  This  method  has  two  serious  disadvantages: 
first,  the  change  in  speed,  which  is  necessary  to  vary  the 
length  of  the  interval  between  flashes,  varies  the  length  of 
the  flashes  also,  so  that  the  effect  of  absolute  flash  length 
cannot  be  easily  determined,  relative  length  only  being  con- 
trollable. Second,  the  pair  of  flashes  is  necessarily  repeated 
rapidly  again  and  again  unless  some  special  device  is  used 
to  cut  off  the  exposure  on  all  but  one  round  of  the  disc;  and 
this  repetition  is  a  factor  which  adds  greatly  to  the  difficulty 
of  the  determination. 

My  apparatus  consisted  of  a  Nernst  glower,  enclosed  in  a 
metal  box,  with  a  lens;  a  disc  of  white  plaster  of  paris;  a 
motor  of  controllable  rate,  driving,  by  a  reducing  belt,  a 
spindle  on  which  discs  of  adjustable  sectors  could  be  rotated; 
and  an  Ewald  chronoscope  for  counting  the  rotations  of  the 
spindle  .during  a  given  time. 

The  lens,  83  cm.  from  the  Nernst  glower,  focused  the  light 
into  an  image,  of  approximately  the  same  size  as  the  glower, 
in  the  plane  of  the  surface  of  the  rotating  sectors  on  the 
spindle,  with  the  long  axis  of  the  image  in  a  radius  of  rotation. 
When  not  interrupted  by  the  sectors,  the  light  fell  on  the 
plaster  surface  placed  35  cm.  beyond  the  focus,  forming  a 
nearly  rectangular  spot  3.5  by  5  cm.  The  brightness  of  this 
spot  was  not  measured,  but  was  kept  constant  by  maintaining 
a  constant  current  through  the  Nernst  glower,  and  by 
frequently  inserting  a  Lummer-Brodhun  photometer  in  the 
position  of  the  disc,  comparing  the  illumination  of  the  Nernst 
with  that  of  a  standardized  8  c.p.  carbon  lamp.  The  two 
brightnesses  used  were  equal  to  those  produced  on  the  same 


PERCEPTION  OF  TIME-INTERVALS  229 

surface  by  the  8  c.p.  lamp  at  36.5  cm.  and  67.5  cm.1  respec- 
tively. Since  the  rotating  sectors  moved  across  the  beam 
of  light  at  the  focus,  'traveling'  of  the  illuminated  areas  was 
nearly  eliminated;  since  the  focused  image  was  narrow,  the 
time  between  the  beginning  of  the  illumination  (or  the  dark 
period)  and  the  full  illumination  (or  complete  cut-off)  was 
so  small  as  to  be  negligible. 

The  observer  (myself  in  most  cases)  sat  between  75  and 
80  cm.  from  the  plaster  surface,  the  angle  between  his  line 
of  sight  and  the  axis  of  the  Nernst  beam  being  45  degrees. 
The  plane  of  the  plaster  surface  was  so  placed  that  it  made 
equal  angles  with  the  axis  of  the  beam  and  the  line  of  sight. 

With  this  apparatus  I  made  determinations  both  of  the 
time-threshold  for  two  flashes,  and  of  the  critical  frequency 
for  a  series  of  interruptions.  In  the  flicker  work,  a  different 
disc,  with  the  appropriate  sectors  cut  out,  was  used  for  each 
of  the  different  ratios  of  light  to  dark  interval.  In  the  work 
on  time-threshold,  a  combination  of  sectors  was  used,  giving 
two  openings,  from  o°  to  90°  in  width,  separated  by  a  5° 
sector  or  by  a  10°  sector.  The  lengths  of  flash  used  with  the 
5°  interval  were  5°,  10°,  and  by  10°  steps  to  90°:  with  the  10° 
interval,  flashes  of  2.5°,  5°  and  10°  were  used,  also  several 
greater  lengths,  up  to  180°  for  one  flash,  the  other  being 
shorter.  The  flicker  discs  (fifteen  in  number)  had  each  two 
apertures,  with  ratios  of  open  to  closed  ranging  between  1/35 

to  35/1- 

In  working  on  myself  the  method  was  as  follows :  starting 
with  a  speed  of  rotation  such  that , distinct  doubleness  (or 
flicker)  was  observable,  the  speed  was  increased  by  small  steps 
until  a  single  flash  (or  fusion)  was  obtained.  Then,  by 
depressing  a  key  a  circuit  was  completed  through  the  Ewald, 
and  a  circuit-breaker  on  the  spindle,  and  was  allowed  to 
continue  for  ten  seconds:  thus  the  number  of  rotations  in 
ten  seconds  was  registered.  After  recording  the  speed,  it 
was  increased  somewhat  (the  amount  of  increase  at  this  point 
being  purposely  irregular),  and  then  decreased  by  small  steps 

1  That  is,  in  the  first  case,  the  lamp  at  36  cm.  gave  a  brightness  clearly  brighter 
than  that  of  the  Nernst  beam,  and  at  37  cm.  a  brightness  clearly  less. 


23° 


KNIGHT  DUNLAP 


until  the  point  of  doubleness  (or  flicker)  was  reached,  when 
the  speed  was  again  measured.  Three  determinations  were 
usually  made  on  each  setting  of  the  sectors  (or  each  flicker- 
disc),  before  proceeding  to  the  next.  The  longer  series  of 
settings,  or  series  of  discs,  was  gone  through  with  in  this 
way  from  one  to  two  hours,  and  as  one  such  series  a  day  was 
all  an  observer  could  endure,  the  progress  of  the  experiment 
was  necessarily  slow. 

The  observer  was  instructed  to  make  his  judgment  each 
time  rather  quickly,  and  then  look  away  until  the  speed  was 
changed.  Continued  gazing  at  the  lighted  area  was  found 
to  cause  even  a  pronounced  doubleness  or  flicker  to  disappear.1 

The  observations  were  made  with  darkness  adaptation. 
In  working  on  myself,  I  took  the  speed  readings,  and  made 
the  record,  by  a  very  dim  light,  and  then  waited  for  a  minute 
or  so  for  readaptation.  This  procedure  undoubtedly  had 
some  effect  on  the  determinations,  but  this  effect  was  probably 
not  large. 

The  series  of  settings  in  the  groups  were  taken  in  different 
orders  on  different  days,  the  several  orders  being  carefully 

TABLE  I 

FLICKER  AND  FUSION 
Observer  Dunlap 


Sectors  in  Degrees 

Cycles  per  Second 

Durations  in  Sigmas 

Flicker 

Fusion 

Closed 

Open 

Flicker 

M.V.jS 

Fusion 

M.V.£ 

Closed 

Open 

Closed 

Open 

5 

175 

24.12 

5-86  ' 

28.17 

5-93 

i.  IS 

40.29 

0.98 

3448 

10 

170 

28.11 

4.20 

31-9 

4-48 

i-97 

33-59 

1-73 

29-53 

15 

I65 

31.08 

5-Si 

36.00 

5-25 

2.68 

29.49 

2.31 

25-45 

30 

150 

38.56 

5.16 

42.59 

5.62 

4-32 

21.60 

3-91 

19.56 

45 

135 

42.59 

3-5i 

46.25 

4-15 

5-86 

17.60 

5-40 

16.21 

60 

1  2O 

43.84 

3-55 

47-94 

4-69 

7.60 

15.20 

6-95 

13.90 

75 

105 

44.68 

4.00 

49.46 

4-38 

9-32 

13-05 

8.42 

11.79 

90 

90 

45-32 

3-07 

49-47 

4-34 

11.03 

11.03 

10.10 

IO.IO 

105 

75 

45^4 

4.07 

50.22 

4.60 

12.00 

9.12 

11.61 

8.29 

120 

60 

44.81 

3-70 

49-75 

4-94 

14.87 

7-43 

13-39 

6.69 

135 

45 

44-58 

4-23 

49.00 

4-13 

16.82 

5.60 

15.30 

5.10 

150 

30 

41.58 

4.72 

46.73 

3-38 

20.03 

4.00 

17.83 

3.56 

I6S 

15 

38.72 

4-57 

42.92 

5-65 

23.66 

2.15 

21.35 

1.94 

170 

10 

35-66 

5-39 

39-8o 

4-98 

2548 

i-SS 

23.72 

i-39 

175 

5 

29.61 

6.42 

34-04 

6.06 

32.82 

o.93 

28.55 

0.81 

1  This  'flicker  adaptation'  is  not  due  to  brightness  adaptation,  as  later  work  shows. 


PERCEPTION  OF  TIME-INTERVALS 


231 


TABLE  II 

TIME  THRESHOLD.     STANDARD  BRIGHTNESS 

Observer  Dunlap 
i.    A=C,   £=5. 


A°=C° 

Double 

Single 

Bo 

M.V.* 

A  .  Co 

Bo 

M.V.* 

A  =  Co 

5 

19.8 

8.0 

19.8 

I3.8 

12.3 

13.8 

10 

14.9 

10.7 

29.8 

II.  I 

9-9 

22.2 

20 

10.5 

7-9 

42-3 

8.2 

7-9 

32.8 

30 

7-3 

14.7 

43-8 

6.2 

9.1 

37-3 

40 

6-3 

13-5 

50.9 

5-2 

10.7 

41.7 

50 

54 

n.8 

54-6 

4-5 

13-3 

4-59 

60 

4.8 

IO.I 

58.5 

4-i 

II.  2 

50.0 

70 

44 

10.7 

62.3 

3-7 

6.3 

52.9 

80 

4-3 

9-4 

69.6 

3-7 

74 

60.4 

90 

4.0 

8.4 

72.9 

3-5 

9-9 

63.5 

C,  B 


10. 


A°=C° 

Bo 

M.V.0 

Ao 

Bo 

M.V.0 

Ao 

2-5 

5 

10 

28.1 
27.0 
2O.6 

17.8 

n.6 

8-7 

7-o 

I31 

20.6 

20-9 
19.2 
15-9 

I6.5 
I3.8 
II.7 

% 

15-9 

3. 


^° 

Bo 

M.V.jJ 

^<r 

Bo 

M.V.jf 

Ao 

10 

30 
50 
70 
90 

16.0 
n.8 
8.8 
6.6 

5-3 

"-S 

5-7 
8.1 
7-2 
7.8 

33-i 
71.1 
88.3 
92.5 
96.1 

II.9 

94 
7.0 

5-6 
4.6 

6.2 

9i 

4.6 

8.6 
8.1 

23.8 

56.7 
70.8 
78.9 
84.4 

=  10,  B  =  10. 


c° 

Bo 

M.V.* 

Co 

Bo 

M.V.jf 

Co 

20 
60 
IOO 

140 

1  80 

20.8 
22.2 
24-3 
23-9 
21.9 

10.6 
18.4 
8.9 
II-J 

7-5 

41.7 

133-5 
243.6 
335-2 
393-3 

16.3 
16.8 
18.1 
18.0 
15.6 

7-8 
9.2 

1:1 

13-9 

32.6 
117.7 
181.3 

252.5 
280.8 

planned  to  distribute  the  effects  of  practice  over  the  whole 
series. 

The  results  of  my  observations  are  presented  in  Tables  I., 
II.  and  III.  In  Table  I.  the  average  flicker-points  and 
fusion-points  for  the  several  ratios  of  open  to  closed  sectors 
are  given  both  in  cycles  per  second  (i.  e.,  the  number  of 
complete  changes  from  dark  to  light  and  back  to  light  again 
in  a  second);  and  also  in  the  duration  in  thousandths  of  a 
second,  of  the  individual  light  and  dark  periods. 


232 


KNIGHT  DUNLAP 


In  Tables  II.  and  III.  the  average  durations  are  given 
for  'A'  (the  first  flash),  ' B'  (the  dark  intermediate  interval) 
and  'C'  (the  second  flash)  when  the  flashes  appeared  dis- 
continuous ('double'),  and  when  they  appeared  as  one  uniform 
flash  ('single').  Table  II.  gives  results  of  work  with  the 
higher  brightness  described  above;  Table  III.,  with  the  lower 
brightness. 

TABLE  III 

TIME  THRESHOLDS,  Low  BRIGHTNESS 
Observer  Dunlap 
A  =  C,  B  =  5. 


A°  =  C° 

Ba 

M.V.# 

A  =  Ca 

Ba 

M.V.It 

A  =  Gr 

5 
30 
70 

20.5 
8.9 
4-5 

10.7 
7.6 
7-8 

2O.5 
53-9 
63-1 

12.4 
7.2 
4.0 

942 
S.6 
4.8 

12.4 

43-3 
56.8 

TABLE  IV 

TIME  THRESHOLDS:  Low  BRIGHTNESS 
Observer  G.  R.  Wells 
i.    A  =  C,  B  =  5 


A°=  C° 

Double 

Single 

Ba 

M.  V.# 

A  =  C<r 

Ba 

M.V.0 

A  =  C<r 

10 

30 
SO 

19.9 
IO.S 
7-1 

II.O 

9-3 

10.0 

39-9 
63.1 
71.7 

13-9 

8.1 

5-5 

57 
10.3 
10.7 

27.9 
49.1 

55-6 

2.      C  =   10, 


A* 

Ba 

M.  V.  0 

A, 

Ba 

M.VA 

Aa 

30 
50 

I3-I 
II.  2 

n.8 
9.0 

78.9 
II2.4 

9-9 

8.0 

9.2 
8.6 

59-5 
80.7 

3- 

A  =  10,  B 

=  S 

30 

SO 

18.8 
19-5 

10.7 
6-3 

113.3 
195.6 

14.9 
15.0 

i.8.6 
9-7 

89.6 
150.1 

In  Tables  IV.  and  V.  the  results  of  observations  of  two 
other  persons  are  given.  These  observations  were  made 
after  I  had  finished  mine,  and  it  was  not  deemed  necessary 
to  use  all  the  flash-lengths  which  I  had  observed.  In  these 
cases  I  manipulated  the  apparatus  and  recorded  the  measure- 
ments, so  that  the  observers  worked  under  better  conditions 


PERCEPTION  OF  TIME  INTERVALS 


233 


TABLE  V 

TIME  THRESHOLDS 
Observer  H.  M.  Johnson. 
i.     Standard  Brightness 


A°=C° 

Double 

Single 

Bo 

M.  V.0 

A-C. 

^0- 

M.  V.j< 

A  =  Ca 

5 

10 

30 
50 
70 

16.6 

94 
7.0 

5-2 
4-5 

14.2 

12.  1 

10.0 

8.0 
8.6 

16.6 
18.8 

42.2 
52.4 
63.1 

I2.I 

7.8 
5.8 

4-3 

3.8 

9-3 

12.2 
8.9 
4.8 
9.1 

12.1 

I5.6 

34-8 
434 
54-5 

2.     Lower  Brightness 


5 
30 

13-2 
7.0 

7-i 
I3-I 

13-2 
42.0 

10.3 

5.8 

5-7 
9.2 

10.3 
35-2 

than  those  under  which  I  observed,  specifically  as  regards 
adaptation. 

Each  of  the  values  given  in  Tables  L,  II.,  III.  and  V. 
are  averages  of  twenty-five  thresholds.  The  values  in  Table 
IV.  are  averages  of  twenty  thresholds. 

There  are  two  points  of  importance  which  stand  out  in 
these  data.  First,  the  rise  in  rate  of  the  'critical  frequency' 
(flicker  and  fusion  points)  from  the  extreme  inequality  to 
equality  of  open  and  closed  sectors,  in  both  directions  (Table 
II.).  Second,  the  decrease  of  the  time  threshold  with  increase 
in  the  length  of  the  first  flash  (Tables  II.,  IV.  and  V.).  This 
decrease  seems  to  be  altogether  a  function  of  the  first  flash; 
increasing  the  length  of  the  first  flash  with  the  second  flash 
constant  (II.,  3;  IV.,  2)  has  almost  the  effect  of  increasing 
both  flashes;  while  increasing  the  length  of  the  second  flash 
(II.,  4;  IV.,  3)  alone  has  practically  no  effect.  The  slight 
increase  in  the  threshold  in  both  these  cases  is  due  to  the 
increased  difficulty  of  observation  with  the  unequal  length 
and  hence  unequal  appearing  brightness  of  the  flashes. 

In  addition  to  these  points,  it  is  to  be  noted  that  the  time 
thresholds  are  low,  ranging  (with  equal  flashes)  from  4  to  20 
sigmas.  The  comparison  of  these  figures  with  those  obtained 
in  other  experiments  is,  however,  not  now  significant,  since 
we  have  not  as  yet  analyzed  the  various  factors  entering  into 


234  KNIGHT  DUNLAP 

determinations  of  this  sort.  In  addition  to  the  brightness, 
in  regard  to  which  the  a^bove  data  are  not  significant,  the 
factor  of  adaptation  is  probably  extremely  potent.  These 
results  were  obtained  with  fairly  good  darkness  adaptation; 
they  cannot  be  compared  with  results  obtained  with  daylight 
adaptation. 

Among  the  factors  affecting  the  formation  of  judgments, 
the  rapid  repetition  of  the  pair  of  flashes  was  conspicuously 
disturbing.  The  simple  rotation  apparatus  is  not  suited  to 
determinations  of  this  kind. 

WORK  ON  BRIGHTNESS  AND  ADAPTATION 

The  second  set  of  experiments  I  varried  on,  at  Dr.  Hyde's 
invitation,  in  the  Nela  Research  Laboratory  during  the 
summer  months  of  1914.  In  carrying  out  these  experiments 
I  received  much  help  from  the  staff  of  the  laboratory,  and  I 
am  especially  indebted  to  Dr.  Hyde,  the  director  of  the 
laboratory;  to  Mr.  Cady,  assistant  director;  to  Dr.  Lorenz; 
to  Dr.  Cobb;  and  to  Dr.  Johnson.  The  readiness  of  the 
members  of  the  staff  to  give  their  time  to  my  problems,  and 
to  release  to  me  apparatus  from  their  own  experiments,  made 
possible  such  work  as  I  was  able  to  accomplish  in  the  short 
time  I  was  there.  The  greatest  burden  of  the  observations 
fell  on  Mr.  Eric  Martienssen,  to  whom  I  am  indebted  for 
his  careful  and  willing  work,  under  conditions  which  were 
sometimes  trying. 

My  apparatus,  which  need  not  be  described  in  detail, 
consisted  of  the  following  units. 

(a)  A  double  rotator,1  carrying  on  one  axis  of  rotation 
two  arbors;  one  on  the  main  shaft  and  the  other  on  a  sleeve 
on  that  shaft,  the  sleeve  being  geared  to  an  auxiliary  shaft 
and  that  back  to  the  main  shaft,  so  that  the  sleeve  made 
one  rotation  for  nine  of  the  shaft.  The  arbor  on  the  sleeve 
carried  a  large  metal  disc  with  a  4<D-degree  aperture.  Variable 
cardboard  sectors  were  carried  by  the  faster  moving  arbor. 
When  the  axis  of  light  is  parallel  to  the  shaft  of  this  apparatus, 

1  This  piece  of  apparatus  was  made  under  my  direction  in  the  Physics  workshop 
of  The  Johns  Hopkins  University. 


PERCEP  TION  OF  TIME-IN  TER  FALS  235 

whatever  exposures  are  arranged  through  sectors  on  the 
faster  arbor  are  repeated  every  ninth  revolution  of  the  shaft, 
being  cut  out  the  remainder  of  the  time  by  the  slow  moving 
disc. 

The  main  shaft  carried  also  a  loose  gear,  in  mesh  with  a 
gear  on  the  driving  motor;  with  an  electro-magnetic  clutch 
of  my  devising,  so  that  the  disc  and  sectors  could  be  stopped 
for  adjustment  without  stopping  the  driving  motor;  and 
could  be  started  again  without  jerk  by  turning  the  current 
gradually  on  the  clutch  magnet.  The  same  shaft  also  carried 
a  cylinder  of  brass  and  hard  rubber,  on  which  rested  two 
brass  brushes,  so  that  the  rotations  could  be  counted  by  a 
step-up  mechanism  operated  by  the  make-and-break  of  the 
circuit. 

(b)  A  nitrogen-filled  lamp,  with  the  wire  in  a   straight 
compact  coil;  operated  in  these  experiments  at  85,  120,  200 
289  and  400  watts.     The  image  of  the  coiled  wire  was  focused, 
by  suitable  lenses,  on  a  slit,  to  cut  off  light  reflected  from  the 
surface  of  the  lamp  bulb;  and  by  other  lenses  refocused  in  the 
plane  of  the  sectors  carried  on  the  faster  moving  arbor  of  the 
rotation  apparatus  described  above.     The  axis  of  the  beam 
of  light  was  parallel  to  the  shaft  of  the  rotation  apparatus, 
and  the  long  axis  of  the  image  was  radial  to  the  shaft. 

The  lamp,  the  slit  and  the  lenses  were  enclosed  in  a  large 
hood  of  black  felt  drawn  over  a  wooden  framework,  with  an 
aperture  just  large  enough  for  the  convergent  beam  to  emerge. 

(c)  A  movable  screen  located  just  beyond  the  slow-moving 
disc  of  the  rotator  and  operated  by  a  hand  lever.     By  raising 
this  screen  shortly  before  the  disc  made  an  exposure,  and 
lowering  it  shortly  afterwards,  a  single  exposure  of  the  interval 
arranged  through  the  sectors  was  allowed.     The  manipula- 
tion of  this  screen  required  no  accurate  timing,  since  the  slow 
disc  allowed  exposure  every  ninth  rotation  of  the  sectors  only. 

(d)  A  lens,  just  beyond  the  hand  screen,  decreased  the 
divergence  of  the  cone  of  light,  increasing  the  brightness  of 
the  surface  illuminated. 

(i)  A  plaster  disc,  surfaced  with  magnesia,  illuminated 
by  the  cone  of  light.  This  disc  was  12.5  cm.  in  diameter,  and 


236  KNIGHT  DUNLAP 

about  half  the  diameter  of  the  light  cone  at  the  point  of 
insertion  of  the  disc  and  had  a  background  of  black  velvet 
upon  which  the  light  around  the  disc  was  negligible.  The 
plane  of  the  disc  was  vertical,  but  was  at  an  angle  of  30°  from 
the  plane  perpendicular  to  the  axis  of  the  cone  of  light. 

The  observer  sat  so  that  his  binocular  line  of  sight  was 
perpendicular  to  the  disc,  which  was  about  165  cm.  from  his 
eyes. 

(/)  A  miniature  projection  lamp,  with  a  small  incan- 
descent bulb  entirely  enclosed,  established  out  of  the  range 
of  the  observer's  vision,  cast  on  the  object  disc  a  group  of 
four  small  dots,  which  served  excellently  as  a  fixation  mark. 

(g)  Eight  mazda  lamps,  totalling  600  watts,  so  disposed 
in  the  room  that  the  walls  were  illuminated,  especially  the 
wall  in  front  of  the  observer — the  wall  behind  the  plaster 
disc — but  the  lamps  were  screened  from  the  observer's  eyes. 
These  lamps  were  controlled  by  a  single  switch. 

(h)  A  single  mazda  lamp  in  a  long  black  cardboard  tunnel, 
arranged  to  throw  continuous  illumination,  when  desired,  on 
the  disc. 

(i)  An  Ewald  chronoscope,  for  counting  the  rotations  of 
the  sectors,  as  a  control  of  the  accuracy. 

(/)  A  synchronous  motor1  for  driving  the  rotator.  This 
had  eight  poles,  and  working  on  60  cycle  A.C.  current  gave 
15  rotations  per  second.  This  motor  was  geared  to  the  main 
shaft  of  the  rotator  (a),  the  ratio  to  the  gear  on  the  motor 
shaft  being  I  to  3.  The  main  shaft  therefore  made  five 
rotations  per  second,  so  that  for  the  sectors  carried  by  the 
arbor  on  the  main  shaft  9°  equalled  5  a.  The  variations  in 
speed,  due  to  variations  in  current  frequency,  were  negligible 
during  the  periods  of  work. 

(k)  A  small  D.C.  motor  for  starting  the  synchronous 
motor.  This  starting  motor  was  belted  to  a  one-flanged 
pulley  on  the  shaft  of  the  synchronous  motor  so  that  the  belt 
could  be  thrown  off  when  the  synchronous  motor  was  working 
properly.  A  stroboscope  disc  mounted  on  the  same  shaft, 
and  illuminated  by  a  15-watt  lamp  on  the  A.C.  current, 

1  This  motor  was  one  which  Dr.  Lorenz  had  constructed  for  his  use.  The  strobo- 
scopic  method  of  starting  the  motor  was  also  suggested  by  him. 


PERCEPTION  OF  TIME-INTERVALS  237 

indicates  the  proper  moment  for  turning  on  the  synchronous 
motor. 

The  five  wattages  used  on  the  lamp  gave  brightnesses  on 
the  object  disc  of  3,  10,  36,  82  and  168  candles  per  square 
meter.  This  range  of  illuminations  seemed  adequate  for  the 
investigation  of  the  effects  of  brightness,  which  was  the  first 
point  I  had  planned  to  attack. 

The  results  of  the  preliminary  experiment,  reported 
above,  had  shown  clearly  that  the  threshold  for  doubleness 
(measured  in  terms  of  the  dark  interval)  depends  on  the 
length  of  the  flashes,  especially  of  the  first  flash,  although  the 
absolute  magnitudes  of  the  thresholds  as  determined  in  those 
experiments  could  not  be  supposed  to  be  very  significant. 
It  would  therefore  be  possible,  theoretically,  to  determine 
thresholds  in  either  of  two  ways:  first,  by  keeping  the  dark 
interval  constant  and  varying  the  flashes;  and  second,  by 
keeping  the  flashes  constant  and  varying  the  dark  interval. 
It  would  seem  equally  useful  to  work  out  the  thresholds  in 
flash  length  for  several  fixed  dark-interval  lengths,  and  to 
work  out  the  thresholds  in  dark-interval  length  for  several 
fixed  flash-lengths.  In  either  case  the  effect  of  the  brightness, 
and  of  adaptation  could  (it  would  seem)  be  worked  out  in 
an  adequate  way. 

In  the  manipulation  of  apparatus,  the  first  procedure  is 
far  the  simpler.  The  sector  adjustments  are  not  so  com- 
plicated, and  hence  the  progress  of  the  experiment  should  be 
more  rapid.  Realizing  that  the  work  would  at  best  be  slow, 
I  chose  the  plan  which  offered  this  important  advantage. 

Observations  were  made  at  first  with  dark  adaptation 
exclusively.  The  subject  was  kept  in  the  room  from  ten  to 
twenty  minutes  before  commencing  work,  according  as  he 
had  come  in  from  outdoors,  or  from  more  or  less  dimly 
lighted  work  rooms.  No  warning  signal  other  than  the 
normal  sound  of  the  electro-magnetic  clutch  in  taking  hold, 
was  needed  by  the  observer.  The  motor  ran  continuously, 
and  the  clutch  was  thrown  in  when  an  observation  was 
desired.  The  rotator  t picked  up'  full  speed  in  less  than  a 
second;  the  hand  screen  was  lifted  about  two  seconds  after 


23  8 


KNIGHT  DUNLAP 


the  clutch  was  thrown  in.  The  four  dots  of  light  in  the 
center  of  the  disc  fixed  the  line  of  sight  before  the  flashes 
occurred.  Four  repetitions  of  the  exposure  were  given  in 
succession,  but  the  observer  usually  gave  his  judgment  after 
the  second  or  third. 

Observations  were  carried  on  for  some  time  by  Martienssen 
and  myself  by  this  method,  using  the  procedure  of  'serial 
groups/  but  the  results,  although  interesting,  were  of  little 
value  for  the  purposes  of  the  experiment.  Variations  in  the 
durations  of  the  flashes  produced  variations  in  the  apparent 
brightness  and  apparent  color  of  the  disc,  which  were  at  first 
extremely  confusing,  and  on  which  finally  the  judgments  came 
to  depend,  rather  than  on  any  real  appearance  of  '  doubleness' 
or  *  singleness.'  One  set  of  five  hundred  judgments  by 
Martienssen,  which  are  typical,  are  given  in  Table  VI. 

TABLE  VI 

Martienssen 
Dark  interval  250-.     Brightness  82  c.  per  sq.  m. 


Two  Flashes 

Double 

Single 

One  Flash 

Double 

Single 

70<r 
60 
60 
40 
30 

48 
36 
38 
32 
41 

/> 

H 
12 

18 
9 

I40a 
120 
100 
80 
60 

0 
0 

3 
II 
12 

SO 

SO 

47 
39 
38 

In  this  table  the  first  column  gives  the  length  of  flash  where 
two  were  used,  the  second  and  third  columns  giving  the 
number  of  judgments  of  double  and  single  for  each  flash- 
duration.  The  fourth  column  gives  the  durations  of  the 
single  flashes,  each  equal  to  the  sums  of  the  two  in  the  corre- 
sponding pair;  the  fifth  and  sixth  columns  giving  the  number 
of  judgments  of  single  and  double  respectively  for  each  of 
these  single  flash  durations. 

The  increasing  difficulty  of  discrimination  is  here  shown, 
not  so  much  by  the  increased  tendency  to  call  the  double 
flashes  single,  as  by  the  tendency  to  call  the  single  flashes 
double.  Obviously,  no  definite  threshold  can  be  determined 


PERCEPTION  OF  TIME-INTERVALS 


239 


when  this  tendency  is  present.1  This  tendency,  it  must  be 
noted,  is  not  due  to  mere  confusion;  as  we  shall  see  later,  a 
single  flash  often  appears  distinctly  double,  and  with  the 
same  sort  of  doubleness  as  is  noticed  in  a  really  double  flash. 
In  this  particular  set  of  observations,  however,  the  judgments, 
according  to  the  observer's  report,  were  based  largely  on 
differences  in  apparent  brightness  and  color;  at  least  this 
seemed  to  him  to  be  the  case  in  the  latter  part  of  the  set. 

TABLE  VII 

Martienssen 
Dark  interval  250-.     Brightness,  3  c.  per  sq.  m. 


Two  Flashes 

Double 

Single 

One  Flash 

Double 

Single 

50<r 

26 

4 

Io6<r 

3 

23 

50 

16 

4 

80 

4 

16 

30 

18 

2 

60 

2 

18 

20 

15 

5 

40 

4 

16 

IO 

IS 

5 

20 

ii 

9 

The  results  of  a  set  of  observations  by  Martienssen  with 
lower  brightness  are  given  in  Table  VII.  Results  of  a  set 
of  observations  by  Dr.  Johnson  on  the  moderate  brightness 
are  given  in  Table  VIII.  Other  sets  with  different  brightnesss 
gave  results  of  the  same  order. 

TABLE  VIII 

Johnson 
Dark  interval  250-.     Brightness,  82  c.  per  sq.  m. 


Two  Flashes 

Double 

Single 

One  Flash 

Double 

Single 

Soa 
40 
30 

20 

20 
17 
23 
IO 

0 
3 
7 
10 

IOO<r 
80 
60 
40 

I 

7 
4 
5 

19 

11 
15 

In  this   set  of  observations,  the  observer's  judgment  was 
influenced  very  largely  by  the  apparent  duration  of  the  total 

xThis  condition  is  similar  to  that  found  in  attempting  to  determine  the  'two 
point'  threshold  by  simultaneous  stimulation  of  the  skin.  No  threshold  can  be  de- 
termined, since  one  stimulation  frequently  is  perceived  as  two,  and  hence  the  least 
separation  of  two  points  giving  a  certain  percentage  of  perception  of  two  has  no  definite 
significance. 


240  KNIGHT  DUNLAP 

exposure;  the  greater  duration  of  the  two  flashes  was  noticed, 
especially  with  the  shorter  flash-lengths,  and  this  tended 
more  and  more  to  become  the  criterion  of  doubleness. 

The  procedure  by  groups  (£ method  of  serial  groups'),  it 
was  clear,  could  not  be  used  in  this  experiment.  The  secon- 
dary criteria — in  this  case  the  differences  in  brightness,  color, 
and  duration — are  made  maximally  conspicuous  by  this 
method,  and  judgments  strictly  on  the  points  under  examina- 
tion are  made  practically  impossible.  I  therefore  attempted 
to  use  the  shuffled  series  procedure,  still  clinging  to  the 
method  of  constant  dark  interval.  A  few  series,  however, 
showed  that  this  method  was  not  practicable,  even  when  the 
better  procedure  was  employed,  since  the  differences  in 
brightnesses  and  color  still  were  very  conspicuous.  The 
regular  progression  procedure  ('method  of  minimal  change') 
accentuated  these  secondary  criteria  still  more. 

The  effects  of  the  total  duration  had  been  foreseen,  and  I 
had  expected  to  introduce  variations  in  which  the  single  flash 
should  be  equal  in  length  to  the  two  flashes  plus  the  dark 
interval.  This  variation  was  found  to  be  inapplicable  because 
it  would  have  accentuated  the  brightness  differences.  For 
example;  the  greater  brightness  of  the  100  a  flash  as  com- 
pared with  the  two  successive  flashes  of  50  a  with  25  a  dark 
interval,  would  be  still  greater  if  the  lengths  of  the  two  flashes 
were  reduced  to  37.5  a  each. 

The  next  attempts  were  made  by  the  method  of  constant 
flash-length,  using  the  ' shuffled  series'  procedure.  With  this 
method  the  differences  in  apparent  brightness  are  not  so 
marked  as  with  the  constant  dark-interval  method,  and  by 
this  procedure  these  differences  and  the  differences  in  dura- 
tion are  not  so  disturbing  as  they  are  in  the  serial  group 
procedure.  It  is  possible,  in  other  words,  to  form  judgments 
on  the  apparent  doubleness  or  singleness  alone  of  the  flashes, 
although  it  required  a  high  degree  of  training  in  order  to 
eliminate  absolutely  other  criteria. 

The  results  of  these  next  observations  by  the  shuffled 
series  procedure  are  given  in  Tables  IX.,  X.,  XL  and  XII. 
In  these  tables  the  first  column  gives  the  separation  of  the 


PERCEPTION  OF  TJME-INTERVALS 


241 


two  flashes,  and  the  other  columns  give  the  number  of 
judgments  of  Single'  and  i double'  for  each  of  the  five 
brightnesses.  The  observations  with  all  of  the  brightnesses 
were  obtained  on  the  same  days,  a  series  being  taken  with 
each  brightness  during  each  experimental  period,  the  order 
of  brightness  being  altered  from  day  to  day  in  a  regular  way. 

TABLE  IX 

Martienssen 
Flash  =  500- 


Brightnesses,  Candles  per  Sq.  Meter 

Intervals,  <r 

3                |               10 

36 

82 

168 

d. 

s. 

d. 

s. 

d. 

s. 

d. 

s. 

d. 

s. 

0 

II 

13 

5 

15 

9 

IS 

II 

9 

5 

19 

5 

8 

4 

5 

5 

9 

3 

5 

5 

7 

5 

IO 

6 

6 

7 

3 

5 

7 

7 

3 

8 

4 

15 

9 

3 

5 

5 

9 

3 

6 

4 

9            3 

20 

IO 

2 

4 

6 

ii 

i 

8 

2 

6 

25 

ii 

I 

8 

2 

10 

2 

10 

0 

8 

4 

TABLE  X 

Johnson 
Flash  =  500- 


Brightnesses,  Candles  per  Sq.  Meter 


Intervals,  <r 

3 

10 

168 

d. 

s. 

d. 

s. 

d. 

s. 

0 

4 

16 

0 

20 

0 

20 

5 

S 

5 

O 

10 

2 

8 

10 

7 

3 

2 

8 

j 

7 

IS 

8 

2 

4 

6 

8 

2 

20 

10 

0 

9 

i 

9 

I 

25 

10 

O 

8 

2 

10          |            O 

Other  series  were  taken  with  light  adaptation.  In  this 
work  the  room  was  lighted  by  the  mazda  lamps  referred  to 
under  (g),  and  the  observer  was  adapted  to  the  brightness  of 
the  plastered  wall  due  to  this  illumination.  When  ready  to 
make  the  observation,  the  lights  were  switched  off,  approxi- 
mately 1.5  seconds  before  the  exposure  of  the  flashes  (or 
flash).  This  interval  was  timed  by  watching  the  exposure 
on  the  hand-screen;  and  turning  off  the  lights  immediately 


242 


KNIGHT  DUNLAP 


after  such  exposure.  Then  the  hand-screen  was  lifted,  and 
since  the  exposure  occurred  every  1.8  seconds  (the  rotation- 
period  of  the  slow  moving  disc)  the  interval  between  the 
turning  off  of  the  mazda  lamps  and  the  exposure  on  the  object 
disc  was  timed  sufficiently  well. 

TABLE  XI 

Martienssen 
Light  Adaptation.     Flash  =  500- 


Brightnesses,  Candles  per  Sq.  Meter 

Intervals,  <r 

3 

36 

168 

d. 

s. 

d. 

s. 

d. 

s. 

O 

5 

25 

6 

24 

3 

27 

5 

2 

17 

12 

13 

6 

14 

10 

IS 

6 

15 

S 

14 

16 

IS 

17 

2 

18 

2 

19 

i 

TABLE  XII 

Johnson 
Light  Adaptation.     Flash  —  SO<T 


Brightnesses,  Candles  per  Sq.  Meter 


Intervals,  a 

3 

36 

168 

d. 

s. 

d. 

s. 

d. 

s. 

0 

0 

25 

2 

23 

S 

20 

5 

5 

IS 

12 

13 

9 

II 

10 

13 

6 

10 

10 

18 

2 

15 

24 

i 

16 

3 

19 

I 

This  method  of  working  with  light  adaptation  seems  quite 
satisfactory.  An  interval  must  be  allowed  between  the 
turning  off  of  the  adaptation  light  and  the  beginning  of  the 
stimulus  light,  to  allow  muscular  recovery.  The  one-and-a- 
half  second  period  seemed  to  be  about  the  shortest  which 
could  be  used.  Of  course  a  slight  amount  of  adaptation 
occurs  within  this  period,  but  this  is  kept  constant  through- 
out. 

Series  with  darkness  adaptation  followed  the  work  with 
light  adaptation.  Results  of  one  group  of  series  on  Mar- 
tienssen are  given  in  Table  XIII.  The  remainder  of  the 


PERCEPTION  OF  TIME-INTERVALS 


243 


work  on  this  observer  and  on  Dr.  Johnson  was  directed  to 
'feeling  out'  methods,  and  does  not  lend  itself  to  tabulation. 


TABLE  XIII 

Martienssen 
Dark  Adaptation.     Flash  =  25  <r 


Intervals,  <r 

Brightness,  Candles  per  Sq.  Meter 

3 

36 

168 

d. 

s. 

d. 

s. 

d. 

s. 

0 

IS 

20 

25 

7 
9 
13 
14 

7 
S 
i 
o 

3 
9 
13 
14 

II 

S 

i 
o 

I 

9 
8 
II 

13 

I 

3 

From  the  results,  as  tabulated,  little  can  be  inferred  as 
to  the  effect  of  brightness.  It  is  evident  that  adaptation  is 
an  important  factor.  The  factor  of  greatest  consequence, 
however,  is  the  tendency  to  see  the  single  flash  as  double. 
The  effects  of  this  tendency  are  found  in  the  tabulated 
results,  especially  with  the  lowest  brightness,  and  were  still 
more  evident  in  the  work  not  tabulated.1  Attempts  to  use 
flashes  longer  than  50  a  proved  fruitless  on  account  of  this 
tendency.  At  75  cr,  for  example,  there  was  a  large  increase  in 
the  number  of  c double'  judgments  on  single  stimuli.  There 
is  a  limit,  however,  beyond  which  the  double  appearance  is  not 
found.  It  may  be  useful,  later,  to  determine  both  the  upper 
limit  and  the  lower  limit  for  the  fallacious  doubling,  but  this 
is  a  determination  of  the  most  difficult  sort. 

The  double  appearance  of  the  single  flash  may,  with  prac- 
tice, be  distinguished  from  the  true  'doubleness.'  That  is, 
there  are  times  when  the  'doubleness'  of  a  single  flash  is 
clearly  different  from  the  'doubleness'  of  two  successive 
flashes,  if  the  one  and  the  two  are  shown  with  but  little 
pause  between.  This  discrimination  is  apt  to  be  lost  at  any 
time,  however,  and  the  pseudo-'doubleness'  taken  for  real 
'doubleness.' 

As  an  illustration  of  the  discrimination,  the  following 
observation  of  Dr.  Johnson  will  serve. 

1  In  many  cases,  both  with  one  flash  and  with  two  flashes,  the  appearance  was 
'double'  on  first  exposure  and  'single*  on  the  succeeding  exposures. 


244  KNIGHT  DUNLAP 

1.  With  the  brightness  =  36  (c.  per  sq.  meter),  two  400- 
flashes   were   distinguished    from   one   80  <r   flash   when   the 
interval  was  20  <r;  with  15  a  interval,  the  one  flash  and  the 
two  flashes  looked  equally  double. 

With  brightness  =  3,  the  two  were  distinguished  from 
the  one  with  150-  interval. 

With  brightness  =  168,  discrimination  was  clear  at  25  <r; 
not  at  20  0-. 

2.  With  two  25  o-  flashes,  and  one  50  <r  flash,  the  differ- 
ence was  clear  when  the  interval  was  35  o-,  with  all  the  bright- 
nesses, equal  'doubleness'  at  30  a*. 

3.  With  two  10  <7  and  one  20  <r  flashes,  the  discrimination 
was  clear  when  the  interval  was  55  o-  for  the  3  and  36  bright- 
nesses, and  40  a-  for  the  168  brightness.     Below  these  points 
the  'doubleness'  was  the  same. 

Similar  observations  by  Dr.  Cobb  gave  the  following 
results: 

1.  Two  25  ff  flashes  and  one  500-  flash,  with  brightness 
=  3,  'doubleness'  clear  at  400-  interval.     With  brightness 
36  and  168,  'doubleness'  clear  at  30  cr  interval. 

2.  Two   50  <r  flashes   and   one    100  a  flash,   with   bright- 
ness =  3,  clear  at  20  a. 

With  brightness  =  36,  clear  at  25  a. 
With  brightness  =  168,  clear  at  30  a. 

3.  Two   10  a  flashes  and  one  20  a  flash,  with  3   and  36 
brightnesses,  not  clear  below  50  a  (no  longer  interval  used) : 
with  168,  clear  at  45  <r. 

4.  Two  75  o-  flashes  and  one  1500-  flash,  brightness  =  3, 
clear  at   10  a  interval.     Brightness  =  36  and   168,   clear  at 
15  <r  interval. 

On  the  whole  we  cannot  conclude  that  increasing  the 
brightness  of  the  flashes  increases  the  distinction  of  the 
doubleness  of  two.  This  is  a  matter  that  is  dependent  upon 
the  absolute  length  of  the  flashes.  In  subsequent  work, 
carried  out  on  the  two  observers  listed  above,  and  on  Dr. 
George  R.  Wells,  the  effect  of  brightness  was  brought  out 
directly  by  trying  various  intervals  in  succession  with  the 
same  flash-lengths.  This  work,  while  agreeing  with  that 


PERCEPTION  OF  TIME-INTERVALS  245 

reported  above,  brought  out  the  further  fact  that  the  effect 
of  intensity  variations  on  successive  flashes  which  are  hardly 
distinguished  at  best  because  of  the  shortness  of  the  interval, 
is  not  the  same  as  the  effect  on  succession  with  longer  inter- 
vals. 

These  observations  are  not  consistent  with  the  tabulated 
results,  but  there  is  no  reason  why  we  should  expect  them  to 
be  so,  since  the  conditions  of  observation  were  entirely  dif- 
ferent. We  must  always  distinguish  in  problems  of  this  kind 
variations  in  the  actual  observable  phenomena  established 
by  the  experimental  conditions,  and  the  variations  in  the 
observations  of  these  phenomena  which  may  be  due  to  the 
same  conditions.  For  example:  the  sensible  content  from 
two  (successive)  stimulations  may  be  different  from  the 
sensible  content  due  to  a  single  stimulation,  and  yet  on 
account  of  the  circumstances  of  observation,  the  difference 
may  not  be  noted.  On  the  other  hand,  a  sensible  content  of 
a  certain  sort  may  now  be  judged  like,  now  be  judged  different 
from,  a  content  from  which  it  differs  slightly,  according  as 
the  conditions  of  observation  throw  this  difference  in  relief, 
or  minimize  it. 

MY  OWN  OBSERVATIONS 

During  the  course  of  the  experiments  reported  above,  I 
acquired  a  considerable  facility  in  observation,  since  I 
watched  the  flashes  while  having  full  knowledge  of  the 
stimulus  conditions.  I  did  not  record  my  observations  during 
the  work  with  the  other  observers,  since  the  necessity  of 
conducting  the  experiments  for  them,  and  especially  the 
attention  to  speed  and  accuracy  in  the  adjustment  between 
exposures,  was  a  disturbing  factor. 

Later  I  made  observations  (with  knowledge)  myself  under 
satisfactory  conditions.  In  these  cases  I  worked  with  the 
'progressive  procedure,'  starting  alternately  with  a  setting 
(width  of  dark  interval)  giving  no  doubleness,  and  one  giving 
doubleness.  • 

This  work  was  done  at  night,  and  the  results  on  different 
nights  did  not  agree  absolutely.  There  was,  however,  a 


246 


KNIGHT  DUN  LAP 


general  uniformity,  such  as  is  indicated  in  Table  XIV.,  in 
which  are  given  the  results  on  four  nights  during  August. 
The  figures  given  are  not  averages,  but  absolute  values  in  the 
scale  of  5  a  steps;  the  points  at  which  (and  above  which)  the 
flashes  were  always  seen  'double'  (d.)  and  at  which  and 
below  which  they  were  seen  'single'  (s.)  on  that  night  under 

TABLE  XIV 

Dunlap 

Flash  =  500- 

i.    Aug.  4 


Brightness 

Dark  Adap. 

Light  Adap. 

Constant  Light 

d. 

s. 

d. 

s. 

d. 

s. 

10 
36 
82 

168 

40 
40-50 
40-50 
40 

0000 

2O 
20 
20 
IO-30 

5 

5 
5 
5 

2O 
2O 
20 
20 

5 
5 
5 
5 

2.      Aug.  22. 


Brightness 

Dark  Adap. 

Light  Adap. 

d. 

s. 

d. 

s. 

3 
10 
36 

82 

168 

25 
25 
25 
25 
25 

IS 
IS 
15 
IS 
15 

2O 
15 

5 
5 

10 

IO 

5 

3.    Aug.  23 


Dark  Adap. 

Light  Adap. 

Constant  Light 

Brightness 

d. 

s. 

d. 

s. 

d. 

s. 

3 

20 

10 

20 

S-io 

5 

2-5 

10 

2O 

10 

10 

? 

5 

2.5 

36 

20 

5-IO 

5 

? 

10 

S 

82 

20 

IS 

5 

? 

10 

5 

168 

20 

10-15 

5 

? 

10 

5 

the  conditions  indicated.  When  the  threshold  varied  during 
the  test,  the  variation  is  indicated.  The  observation  lasted 
from  one  to  two  hours,  with  periods  of  rest  for  the  eyes. 

In  certain  cases,  no  definite  determination  was  made  for 
the  'single'  point.     This  is  indicated  by  a  question  mark. 


m 


PERCEPTION  OF  TIME-INTERVALS  247 


The  series  with  dark  adaptation  and  light  adaptation  were 
taken  as  in  the  work  on  other  observers.  The  results  in  the 
columns  under  'constant  light'  were  obtained  while  the 
object  disc  was  illuminated  by  the  'tunnel  lamp'  described 
above,  (h).  In  this  case,  the  flashes  were  superimposed  on  a 
constantly  lighted  surface.  Except  for  the  illumination  of 
the  disc,  the  room  was  dark  during  these  observations. 

The  observations  included  in  Table  XIV.  were  with  50  a 
flashes  only;  with  25  a  the  results  were  more  uniform;  for  all 
brightnesses,  with  dark  adaptation,  the  double  point  was  at 
40  or,  the  single,  at  30  cr;  with  light  adaptation,  the  points 
were  20  cr  and  10  cr  respectively;  with  light  adaptation  and 
constant  light  in  the  disc,  20  a  and  5  a.  With  dark  adapta- 
tion and  constant  illumination,  the  single  point  was  5  a,  but 
the  double  point  was  variable  (lOcr— 20  cr).  Flashes  above 
50  o-  (up  to  75  d)  gave  more  variable  results. 

The  general  influence  of  light  adaptation  and  constant 
illumination  was  demonstrated  on  a  number  of  persons, 
including  the  observers  listed  above,  by  a  simple  method. 
The  sectors  were  set  so  that  with  dark  adaptation  the  two 
flashes  appeared  ' single,'  or  the  judgment  was  'doubtful.' 
Then  the  eye  was  light-adapted  for  a  short  time,  and  observa- 
tion showed  a  striking  change,  it  being  possible  with  any 
observer  to  change  the  judgment  from  'distinctly  single'  to 
1  distinctly  double'  by  this  means.  The  addition  of  a  constant 
illumination  served  the  same  purpose.  With  certain  settings 
of  the  sectors,  and  a  faint  constant  illumination  on  the  disc 
the  two  flashes  appeared  'single';  by  increasing  the  constant 
illumination  a  point  was  reached  at  which  the  appearance 
was  clearly  double.  This  point  varied  with  different  obser- 
vers, and  at  different  times. 

THE  SOURCES  OF  DIFFICULTY 

The  results  of  the  investigations  of  the  visual  time 
threshold  up  to  this  point  are  as  follows: 

I.  The  effects  of  brightness  of  the  light  are  variable, 
depending  on  the  other  factors  in  such  a  way  that  no  con- 
clusion can  be  drawn  as  yet  concerning  their  effects. 


248  KNIGHT  DUNLAP 

2.  The  threshold  is  lower  for  the  light-adapted  eye  than 
for  the  dark-adapted  eye.     This  holds,  at  least,  for  certain 
light-adaptations. 

3.  The   threshold   is    lower   for   an   interval   marked    by 
flashes  added  to  a  continuous  stimulation,  than  flashes  in  a 
dark  field.     This  holds  for  a  wide  range  of  constant  illumin- 
tion,  the  threshold  varying  usually  with  the  brightness  of 
the  constant  illumination  up  to  the  point  where  the  additions 
lose  in  distinctness. 

4.  A  single  flash  is  frequently  seen  as  a  succession  of  two, 
and  although  this  'twoness'  may,  under  proper  conditions, 
be  discriminable  from  actual  'twoness/  these  conditions  are 
not  easily  actualized  in  quantitative  work. 

In  consequence  of  this  (and,  possibly,  other  factors) 
quantitative  work  by  the  standard  methods  is  not  possible; 
at  least  the  results  of  such  work  are  unreliable.  Special 
methods  must  be  devised. 

5.  It  is  impossible  to  train  observers  on  the  light  threshold 
problem  in  a  limited  time  (two  or  three  months).     Observa- 
tions are  of  value  only  if  made  by  persons  having  a  long 
training  in  that  particular  work.     In  this  respect,  the  time- 
threshold  problem  differs  markedly  from  certain  other  prob- 
lems, e.  g.,  of  flicker.     The  length  of  training  required  cannot 
be  specified,  but  possibly  should  extend  over  a  period  longer 
than  a  year. 

The  most  interesting  question  coming  out  of  these  observa- 
tions concerns  the  apparent  doubleness  of  a  single  flash  under 
certain  conditions.  This  doubleness  of  appearance  is  un- 
questionable; the  flash  has  at  times  a  striking  £ one-two' 
progression. 

This  fictitious  doubleness  is  not  exclusively  a  dark- 
adaptation  phenomenon,  although  it  is  less  noticeable  with 
light-adaptation.  Constant  illumination,  on  the  other  hand, 
even  of  relatively  low  brightnesses,  completely  abolishes  it. 
We  might  therefore  suppose  it  to  be  due  to  an  iris-reflex:  the 
stimulation  beginning  with  dilated  iris  causes  a  strong  con- 
traction and  immediate  relaxation,  so  that  the  light-flux 
entering  the  eye  drops  and  rises  again  causing  a  depression 


PERCEPTION  OF  TIME-INTERVALS  249 

(' dimple')  in  the  excitation  curve  of  the  retinal  process  in  the 
same  way  as  in  a  rapid  succession  of  two  flashes. 

The  occurrence  of  the  flash  provokes  a  strong  visual  reflex, 
noticed  by  every  observer.  One  feature  of  this  reflex  is  an 
increase  in  accommodation:  at  the  end  of  the  stimulation, 
this  accommodation  is  for  a  point  nearer  than  the  object-disc, 
and  the  relaxation  necessary  to  re-accommodate  for  the  disc 
is  easily  noticed.  Since  accommodation  and  iris-contraction 
go  together  this  may  be  taken  as  indicating  the  iris  factor 
suggested  above. 

On  the  other  hand,  the  chief  factor  may  be  retinal.  The 
retinal  process  may  rise  to  a  point  higher  than  its  'normal' 
for  the  intensity  of  stimulation,  and  then  drop  back.1  The 
drop  may  be  below  normal,  with  an  immediate  second  rise; 
thus  the  'dimple'  which  normally  produces  the  appearance 
of  doubleness  may  occur  independent  of  iris-activity. 

It  is  possible  that  no  'dimple'  may  be  required.  The 
two  drops  in  the  sensation, — one  following  the  excessive  rise, 
and  the  other  at  the  end,  may  be  interpreted  as  'twoness.' 

The  motor-process — adjustment  of  the  eyes — may  be 
connected  with  the  fictitious  doubleness  through  an  actual 
inhibitory  discharge  to  the  retina  accompanying  the  discharge 
to  the  ciliary  muscle.  Efferent  fibers  to  the  retina  are  known 
to  exist,  although  their  function  is  not  known. 

The  motor-process  is  probably  the  cause,  or  connected 
with,  the  severe  effect  of  the  observations.  Both  Martienssen 
and  myself  felt  the  effect  to  a  marked  degree,  the  eyes  becom- 
ing very  irritable,  and  necessitating  frequent  interruptions 
of  the  work. 

Instead  of  being  towards  the  end  or  in  the  middle  of  a  very 
simple  experiment,  or  small  group  of  simple  experiments,  we 
are  now  at  the  place  where  it  is  necessary  to  take  up  a  large 
number  of  points,  not  so  clearly  connected  with  each  other 
as  they  are  contributory  to  the  solution  of  our  initial  problem. 
If  any  light  is  to  be  thrown  on  these  problems,  it  can  come 

1  Such  action  of  a  light  stimulation  on  the  retina  is  called  by  physicists  the 
'over-shooting  of  the  sensation.' 


250  KNIGHT  DUNLAP 

only  through  the  solution  of  these  various  problems,  each  of 
which  involves  an  extended  investigation. 

The  problem,  or  group  of  problems,  which  stand  out 
above  the  others  in  importance,  concerns  adaptation.  I  am 
now  installing  apparatus  and  developing  methods  which 
may  throw  new  light  on  this  topic. 


VOL.  XXII.  No.  4  July,  1915 


THE  PSYCHOLOGICAL  REVIEW 


AN  EXPERIMENTAL  CONTRIBUTION  TO  THE  IN- 
VESTIGATION OF  THE  SUBCONSCIOUS1 

BY  LILLIEN  J.  MARTIN 

Leland  Stanford  Junior  University,  California 

The  subconscious  is  so  often  referred  to  and  so  little 
attention  has  been  given  to  investigating  it  experimentally 
that  it  has  seemed  to  me  a  condensed  summary  of  a  recent 
investigation  I  have  made,  might  possibly  be  of  some  interest. 

In  making  this  study  the  image  method  was  employed. 
That  is,  to  state  very  briefly  the  mode  of  procedure:  in  one 
half  of  the  experiments  the  observer,  usually  with  his  eyes 
closed  or  blindfolded  and  seated  opposite  the  experimenter, 
was  instructed  to  sit  in  a  relaxed  position  and  let  an  image 
(visual  or  auditory,  memory  or  imaginative,  etc.,  depending 
upon  what  was  desired  by  the  experimenter),  arise  of  itself. 
The  observer  was  not  only  not  to  arouse  the  image  but  he 
was  not  even  to  know  its  content  until  he  saw  it  before  him, 
and  only  those  images  were  noted  where  such  instructions 
had  been  entirely  complied  with.  In  the  other  half  of  the 
experiments,  the  observer  was  directed  to  arouse  the  image, 
that  is,  for  example  he  was  instructed  to  decide  on  the  partic- 
ular thing  he  wished  to  visualize  and  to  arouse  the  correspond- 
ing image. 

Stanford  and  Munich  University  students  acted  as  ob- 
servers. 

An  examination  of  the  data  regarding  the  content  of  the 
images,  their  mode  of  arising,  etc.,  shows: 

1  For  fuller  details  of  the  investigation  as  to  the  theory  underlying  it,  the  methods 
used,  the  experimental  data,  etc.,  see  Martin,  'Ein  experimenteller  Beitrag  zur  Er- 
forschung  des  Unterbewussten  (Earth)  and  Uber  die  Abhangigkeit  visueller  Vorstel- 
lungsbilder  vom  Denken,'  Zeit.  fur  Psych.,  70,  212. 

251 


252  LILLIEN  J.  M4RTIN 

1.  The  subconscious  mental  activity  reveals  itself  through 
the  arising  of  images  where  the  observer  did  not  previously 
know  whether  anything  would  be  imaged,  or  if  so,  what  it 
would  be  ;  also,  in  the  arising  of  unwilled  (spontaneous)  images 
in  connection  with  those  willed. 

2.  Evidently,  sometimes  and  in  some  persons,  the  sub- 
conscious thinking  responds  more  quickly  to  the  task  set  than 
does  the  conscious.     This  is  shown  by  the  spontaneous  images 
arising  more  promptly  than  do  the  willed.     That  is,  the  spon- 
taneous image  is  before  the  observer  before  he  has  decided 
what  image  to  arouse  or  it  arises  in  place  of  it. 

3.  The  images  show  that  not  only  the  conscious  but  the 
subconscious  mental  activity  differs  in  richness  of  content 
in  different  individuals. 

4.  In  case  of  all  the  observers — but  in  some  of  them  more 
than  in  others — some  of  the  material  stored  away  under  the 
threshold  has  evidently  remained  as  originally  grouped,  as 
for  example,  when  the  visual  image  of  a  particular  man  in  a 
particular  environment  arises  simultaneously  and   at  once. 
On  the  other  hand,  some  of  the  material  has  evidently  been 
more  or  less  broken  up,  as  for  example,  where  an  eye  arises 
spontaneously,  when  an  imagination  image  of  a  face  is  asked 
and  no  other  features  followed  it  until  aroused  by  a  special 
act  of  will  on  the  part  of  the  observer.     In  case  of  some  of  the 
observers    the    broken-up    memory    material,    the    memory 
elements,  have  been  unconsciously  (as  shown  by  the  observer's 
great  surprise  at  the  content  of  the  visual  images  which  arise) 
recombined  under  the  threshold  into  complicated  and  ap- 
propriate new  groups.     There  has  been  not  alone  a  breaking 
up  of  memory  material   but,  to  use  Ribot's  words,  an  'un- 
conscious elaboration'  of  it.     In  the  observers  with  whom  I 
have  experimented,  the  memory  activity  evidently  predomin- 
ates both  below  and  above  the  threshold  of  consciousness. 

5.  The    memory    and    imagination    material    under    the 
threshold  is  evidently  not  all  on  the  same  stratum  or  level  as 
regards  consciousness,  for  some  of  it  arises  much  more  spon- 
taneously and  quickly  and  has  a  different  content.     Here  too 
individuality  plays  a  great  role. 


INVESTIGATION  OF  SUBCONSCIOUS  253 

6.  From  what  has  been  said   it  will  be   seen,   that   the 
image  method  makes  it  possible  to  obtain  information  regard- 
ing the  past  life  of  the  individual,  the  general  character  and 
the  personal  peculiarities   of  the  thinking  going  on  in   his 
mind,  not  alone  above  but  also  below  the  threshold  of  con- 
sciousness.    The  applicability  of  this  method  in  the  case  of  a 
particular  person  will  of  course  depend  upon  his  ability  and 
habit  as  regards  the  imaging  of  his  conscious  and  subconscious 
thinking. 

7.  The  introspections  show  that  the  spontaneous  images 
are  sometimes  the  point  of  departure  of  the  willed  images, 
that  is,  the  involuntary  image  that  arises  before  the  observer 
has  decided  what  to  will  acts  in  the  way  of  suggestion.     This 
shows  how  important  the  spontaneous  images  must  be  in  our 
daily  life.     Where  the  spontaneous  images  are  in  the  direction 
of  the  work  in  hand,  they  must  save  time  in  that  they  arise 
immediately  and  furnish  material  already  elaborated.     On 
the  other  hand,  if  they  are  not  of  such  a  character  that  they 
can  be  used  directly  in  the  intellectual  work  being  carried  on 
or  as  points  of  departure  for  conscious  thinking  along  the 
desired  line,  they  must  be  an  interruption  and  even  a  hindrance 
in  the  continuing  of  such  thinking.     The  results  show  also  that 
the  spontaneous  images  may  furnish  ideals  as  regards  action. 
In  this  respect  they  may  and  may  not  be  entirely  helpfuL 
One  of  the  observers  who  took  part  in  these  experiments,  has 
very    strong    and    insistent    spontaneous    auditory    images. 
So  insistent  are  they,  that  she  tells  me  that  they  led  to  her 
giving  up  the  study  of  music  to  which  she  had  devoted  several 
years,  and  turning  to  a  totally  different  field  of  work.     She 
says,  that  whenever  she  plays  on  the  piano  the  spontaneous 
auditory  images  precede  what  she  is  playing  and  show  her 
how  imperfect  is  her  execution. 

8.  A  comparison  of  the  content  of  the  voluntary  images 
with  that  of  those  which  are  spontaneous,  shows  that  in  the 
case  of  the  visual  images  of  a  given  observer  what  is  above 
and  below  the  threshold  of  consciousness  is  not  materially 
different. 


254  LILLIEN  J.  MARTIN 

This  result  does  not  support  BinetV  theory  regarding  the 
nature  of  the  subconscious,  which  is,  that  there  are  two  per- 
sonalities running  side  by  side,  one  above  and  the  other  below 
the  threshold  of  consciousness,  as  what  is  above  and  below 
the  threshold  of  consciousness,  as  was  said,  seems  in  the  case 
of  these  observers  not  to  be  materially  different.  It  may 
be  otherwise  in  pathological  persons,  of  course.  Cases  of 
double  personality  certainly  suggest  this.  But  such  special 
cases  do  not  give  Binet's  theory  any  great  universality. 
Nor  does  Meyers's2  theory,  which  has  found  support  among 
workers  in  psychical  research,  that  the  subconscious  is  an 
expression  of  the  infinite  mind,  and  the  conscious  an  individual 
matter  or  a  very  limited  expression  of  the  infinite,  get  support, 
for,  as  was  just  said,  what  is  under  the  threshold  does  not 
seem  enormously  richer  in  content  than  what  is  above.  Nor 
do  I  find  anything  in  these  results  which  leads  me  to  suppose 
that  under  the  threshold  a  mental  condition  exists  which 
makes  it  necessary  to  suppose  that  communication  between 
different  persons  (telepathy)  is  possible  and  which  would 
more  or  less  support  Meyer's  theory.  The  results  do  support 
Prince's3  theory  that  what  is  under  the  threshold  is  an 
expression  of  the  observer's  previous  experiences. 

9.  The  results  have  a  farther  interest  from  the  standpoint 
of  general  psychology. 

A.  They  show  that  the  differences  and  likenesses  between 
spontaneous   and  voluntary  images  ought  not  to  be  over- 
looked in  psychology,  as  has  been  the  case  in  the  past,  since 
through  the  study  and  comparison  of  such  images  we  may  go 
below  the  threshold  of  consciousness   and   get  information 
regarding  what  is  going  on  there. 

B.  They  throw  light  on  what  is  called  inattention  and 
vacillation  of  attention.     We  see  that,  sometimes  at  least, 
this  grows  out  of  the  fact  that  the  person  has  a  flood  of  spon- 
taneous images  and  ideas,  which  impede  and  even  crowd  out 
voluntary  images  and  ideas.     They  explain  why  the  genius 
is  so  impatient  of  restraint  and  may  sometimes  actually  get 

1  On  double  consciousness,  etc. 

2  'Human  Personality,'  I.,  34  ff.,  1904. 

3  'The  Subconscious,'  I  ff.,  1914. 


INVESTIGATION  OF  SUBCONSCIOUS  255 

on  faster  by  letting  himself  go,  and  also  why  the  student  in  a 
field  of  an  exacting  and  foreign  character  as  regards  his  natural 
thinking,  must  take  himself  in  hand  or  fail  altogether  in  his 
work.  I  take  the  following  in  the  way  of  illustration  from 
what  one  of  the  observers  gave  to  protocol: — 

"Als  sich  mein  Studium  begann,  war  es  mir  kaum  moglich, 
mich  in  einer  Vorlesung  irgendwie  zu  konzentrieren,  weil  ich 
bestandig  durch  spontan  auftretende  V.  gestort  wurde.  Ich 
have  dann  versucht,  die  spontanen  V.  zu  verdrangen  und 
grosse  Miihe  darauf  verwendet  und  habe  es  darin  bis  zu  ein^r 
gewissen  Fertigkeit  gebracht,  so  dass  ich  jetzt  spontane  V. 
willkurlich  haben  oder  nicht  haben  kann.  Sobald  ich  mich 
aber  etwas  gehen  lasse,  sind  die  spont.  da,  und  ich  bin  ziemlich 
machtlos  dagegen." 

C.  The  data  obtained  lead  one  to  ask  whether  in  future 
memory  investigations  along  quantitative  lines  the  task  of 
the  investigation  will  not  be  something  more  than  a  filling 
in  of  the  gap  left  in  the  work  of  an  Ebbinghaus  and  a  Miiller, 
something  more  than  a  building  upon  the  results  already 
obtained  by  them.     May  we  not  possibly  be  obliged  to  begin 
again  at  the  very  bottom  and  repeat  the  work  in  order  to 
feel  sure  of  its  foundations.     It  would  seem  from  these  results 
that   instructions    given    by    an    experimenter   favorable    to 
voluntary  effort,  or  the  belief  on  the  part  of  the  observer  that 
he  must  put  forth  his  will  in  connection  with  the  task  set, 
while  favorable  to  voluntary  memory  may  have  been  detri- 
mental to  spontaneous  memory  and  vice  versa.     In  short,  it 
does  not  seem  entirely  impossible  that  two  persons  may  have 
equally  good  memories  as  regards  the  amount  that  can  be 
reproduced,  but  that  like  instructions,  as  for  example,  that 
effort  (resp.  no  effort)  is  to  be  used  in  reproducing  a  given 
material,  may  make  it  appear  that  one  person  has  a  much 
better  memory  than  the  other  or  indeed  that  neither  has  a 
good  memory. 

D.  Again,   these  results   put  in  question  the   results   of 
certain  experiments  of  Rux,1  which  were  inspired  by  Ach. 
Rux  has  attempted  to  measure  the  strength  of  will  by  using 

1  'Ueber  das  assoziative  Aequivalent  der  Determination,'  Untersuchungen  zur 
Psychologic  und  Philosophiey  Bd.  II. 


256  LILLIEN  J.  M4RTIN 

the  quantitative  data  derived  from  memory  experiments 
without  apparently  making  any  attempt  to  show  how  much 
of  the  work  done  was  accomplished  by  voluntary  and  how 
much  by  spontaneous  memory. 

10.  The  results  have  a  pedagogical  interest.  . 

A.  In  that  they  show  that  it  is  possible  to  educate  and 
enrich  the  subconscious. 

B.  In  that  they  lead  one  to  ask  whether  we  may  not  some- 
times be  placing  too  much  emphasis  on  the  employment  of  will 
in  connection  with  the  intellectual  work  to  be  done.     When 
the  student's  work  is  of  a  creative  nature  or  along  the  line  of 
discovery  and  his  spontaneous  thinking  and  images  are  in 
harmony  with  the  field  in  which  he  is  working,  one  can  think 
that  the  director  of  a  leading  institution  in  America  which  is 
devoted  to  scientific  research,  showed  psychological  acumen, 
when  he  urged  the  investigators  working  under  him  to  take 
each  day  some  time  away  from  their  work  not  only  to  give 
their  minds  rest  but  to  free  themselves  from  the  restraint  of 
thinking  in  one  particular  narrow  line. 

THE  IMAGE  METHOD  VERSUS  THE  AUTOMATIC  WRITING  AND 
SPEAKING   METHODS    OF    PENETRATING    BELOW   THE 

THRESHOLD  OF  CONSCIOUSNESS 

Binet  and  others  have  used  the  automatic  writing  method, 
in  investigating  the  subconscious.  As  the  image  method 
will  naturally  come  in  competition  with  the  automatic  writing 
method  in  investigations  along  this  line,  I  have  thought  it 
desirable  to  make  some  experiments  by  this  method  to  ascer- 
tain how  it  compares  as  regards  the  amount  of  data  yielded 
with  the  visual  image  method  in  the  getting  of  information 
of  what  is  going  on  under  the  threshold  of  consciousness. 

The  experimental  results  I  have  given  in  the  work  of  which 
this  paper  is  a  summary.  They  show  (i)  that  while  theo- 
retically the  subconscious  experience  is  reproduced  through 
automatic  writing  without  entering  consciousness,  to  be  cer- 
tain that  this  actually  occurred,  that  is,  to  be  certain  that  the 
experience  did  not  enter  consciousness  and  after  such  entrance 
more  or  less  influence  and  direct  the  writing,  one  must  have 


INVESTIGATION  OF  SUBCONSCIOUS  257 

observers  who  have  the  ability  and  the  training  to  introspect 
very  accurately.  (2)  That  the  image  method  has  a  much  wider 
applicability,  as  it  can  be  employed  with  any  one  who  has 
visual  and  other  images,  while  the  automatic  writing  method, 
as  is  shown  by  these  experiments  and  by  others,  is  very  lim- 
ited in  its  application.  In  these  experiments  only  2  out  of  the 
19  persons  were  really  able  to  respond  to  the  task  set.  (3) 
The  image  method  gives  more  information  in  a  given  period 
of  time  and  thereby  decreases  the  difficulty  of  the  introspec- 
tion. (4)  In  the  image  method  the  experience  is  brought  above 
the  threshold  and  the  observer  is  encouraged  to  give  his  full 
attention  to  what  occurs,  and  he  may  be  directed  to  observe 
particular  things.  (5)  In  the  image  method  it  is  not  necessary 
to  direct  the  movement  connected  with  the  giving  .of  the  in- 
formation into  an  entirely  new  channel  by  substituting  the 
action  of  lower  nerve  centers  (centers  connected  with  sub- 
conscious thinking)  for  the  higher  (centers  connected  with 
conscious  thinking)  which  usually  largely  direct  it.  (6)  In  a 
confirmatory  way  the  writing  method  may  be  made  very 
useful.  The  great  richness,  for  example,  of  what  is  under  the 
threshold  of  consciousness  in  case  of  M.  and  O.  is  shown  by 
both  methods.  (7)  Each  method  also  brings  things  to  the 
attention  not  brought  out  by  the  other  method.  The 
tendency  of  the  writing  movements  to  be  at  the  disposal  of 
what  is  in  consciousness  is,  for  example,  very  noticeable  in  case 
of  some  observers.  In  case  of  M.  and  O.,  what  is  below  the 
threshold  evidently  plays  also  a  role  as  regards  the  writing. 

AUTOMATIC  SPEAKING  METHOD  VERSUS  THE  IMAGE  METHOD 
Of  some  special  cases  of  automatic  speaking  I  have  given 
illustrations  in  my  study  entitled  'Die  Projektionsmethode' 
(p.  5,  105).  From  what  is  heard  by  the  patient  himself  or 
by  the  experimenter,  an  idea  can  be  obtained  of  course  of  what 
is  going  on  under  the  threshold  of  consciousness.  The  words 
occasionally  unconsciously  spoken  by  a  normal  person  give 
one  a  similar  idea.  It  will  be  at  once  evident,  however,  with- 
out any  comparative  experiments  that  the  image  method  has 
a  very  much  broader  field  of  usefulness  because  of  the  dim- 


258  LILL1EN  J.  MARTIN 

culty  of  getting  an  adequate  distraction  in  using  the  automatic 
speaking  method. 

THE  IMAGE  METHOD  VERSUS  THE  PATHOLOGICAL  AND  THE 

PSYCHOANALYTICAL  METHODS  OF  INVESTIGATING  THE 
SUBCONSCIOUS 

The  other  methods  of  investigating  the  subconscious  I  find 
less  satisfactory  than  the  automatic  writing  and  speaking 
methods.  The  objection  to  the  pathological  method,  where 
the  data  regarding  the  subconscious  is  obtained  for  example 
from  cases  of  double  personality,  is  the  feeling  of  doubt  and 
even  mistrust  with  which  one  often  collects  and  examines  such 
data. 

The  objection  to  the  method  of  psychoanalysis  is  that  the 
instruction  given  to  the  patient  to  speak  out  everything  that 
comes  into  his  mind,  gives  a  mass  of  data  which  contains  not 
only  what  is  below  but  what  is  above  the  threshold  and  farther 
that  in  applying  this  method  no  systematic  effort  is  made,  as 
in  the  case  of  the  image  method,  to  separate  out  and  classify 
such  data. 

Taken  all  in  all,  it  seems  to  me,  the  results  show  that  the 
image  method  offers  a  mode  of  penetrating  below  the  threshold 
of  consciousness  which  is  at  least  comparable  if  not  superior 
to  that  offered  by  other  methods. 


EMOTIONAL  POETRY  AND  THE  PREFERENCE 
JUDGMENT 

BY  JUNE  E.  DOWNEY 

The  University  of  Wyoming 

In  a  former  study1  the  writer  reported  somewhat  extensive 
experiments  upon  the  imaginal  reaction  to  poetry  and  the 
influence  of  the  various  forms  of  the  image  upon  the  affective 
and  the  aesthetic  judgment.  The  poetic  fragments  utilized 
in  this  experiment  were  selected  largely  because  of  their 
imaginal  suggestiveness.  Occasional  comments  of  reagents 
upon  certain  fragments  indicated  that  had  highly  emotional 
poetry  been  employed  instead  of  imaginal  poetry  different 
results  might  have  been  obtained. 

Accordingly,  a  second  series  of  experiments  was  planned 
in  order  to  test  the  emotional  factor  in  poetry.  Twenty- 
four  fragments  of  poetry,  somewhat  longer  than  those  of  the 
preceding  test,  chosen  because  of  their  emotional  content,2 
were  utilized.  The  judgments  obtained  are  not,  however, 
directly  comparable  with  those  given  in  the  preceding  series 
since  instead  of  a  grouping  of  the  emotional  fragments  on 
the  basis  of  pleasantness-unpleasantness,  a  grouping  of  the 
fragments  into  eight  groups  according  to  preference  was 
asked  for.  In  group  I  were  to  be  placed,  according  to  type- 
written instructions  placed  before  every  reagent,  the  frag- 
ments liked  best;  in  group  8,  those  liked  least;  the  other 
fragments  in  the  intermediate  groups.  After  this  grouping 
the  reagents  were  instructed  to  shade  the  fragments  in  each 
group,  placing  first  in  each  group  the  fragment  most  liked 
and  shading  from  that  to  the  one  liked  least.  Such  an 

1  "The  Imaginal  Reaction  to  Poetry,"  Univ.  of  Wyom.,  Department  Psychol., 
Bulletin  No.  2. 

2  That  the  fragments  utilized  were  actually  less  imaginal  in  content  than  those 
employed  in  the  previous  test  is  shown  by  the  fact  that  in  proportion  to  the  number  of 
fragments  and  for  the  same  number  of  reagents  they  aroused  only  half  as  many  images. 

259 


260  JUNE  E.  DOWNEY 

arrangement  was  repeated  five  times  at  week-intervals.  Each 
reagent  was  instructed  to  record  his  mood  before  beginning 
his  grouping  and  to  record  it  again  at  the  close  of  the  experi- 
ment. After  the  first  and  the  fifth  preference  arrangement 
the  reagent  was  instructed  to  rearrange  the  fragments,  on 
the  basis  of  the  vividness  of  his  emotional  reaction  to  them, 
in  four  groups :  III.  Reaction  vivid;  II.  Reaction  moderately 
vivid;  I.  Reaction  slight;  O.  No  emotional  reaction.  After 
the  number  of  each  fragment  on  the  second  record  the  reagent 
was  instructed  to  write  a  word  or  phrase  descriptive  of  the 
emotional  content  of  the  fragment.  In  connection  with  the 
second  preference  arrangement,  a  rearrangement  into  four 
groups  as  before  on  the  vividness  with  which  the  reagent 
projected  himself  into  the  content  was  asked  for,  with  a 
complete  account  of  the  kind  of  self-projection  observed  in 
any  case.  With  the  third  preference  arrangement  a  grouping 
of  the  fragments  with  reference  to  the  nature  of  the  inner 
speech  was  asked  for,  together  with  comments  upon  the 
form  of  the  inner  speech  for  each  fragment.  A  fourfold 
grouping  on  the  basis  of  the  vividness  of  the  concrete  imagery 
aroused  by  reading  was  requested  in  connection  with  the 
fourth  preference  arrangement. 

Some  four  weeks  after  the  last  preference  arrangement  a 
grouping  of  the  fragments  into  eight  groups  according  to 
their  beauty  was  obtained.  In  group  I  were  placed  the  most 
beautiful  fragments;  in  group  8  the  least  beautiful;  in  the 
intermediate  groups  the  other  fragments.  As  before,  the 
fragments  were  shaded  within  the  groups.  In  connection 
with  this  grouping  answers  to  the  following  questions  were 
obtained: 

1.  What  do  you  mean  by  ' beautiful'?     Answer  on  the 
basis  of  your  experience  while  arranging  the  fragments. 

2.  In  your  opinion  is   an   arrangement  on  the  basis  of 
beauty  equivalent  to  an  arrangement  on  the  basis  of  prefer- 
ence?    Why? 

3.  Is  an  arrangement  on  the  basis  of  beauty  equivalent  to 
one  on  the  basis  of  pleasantness? 

4.  Would  an  arrangement  on  the  basis  of  pleasantness  be 
equivalent  to  one  on  the  basis  of  preference? 


POETRY  AND  THE  PREFERENCE  JUDGMENT  261 

5.  What  kind  of  emotional  appeal  do  you  prefer  in  poetry? 
Can  you  give  any  reason  for  your  preference? 

6.  What  kind  of  emotional  appeal  do  you  consider  most 
beautiful?     Why? 

Seven  reagents  took  part  in  the  experiment;  all  had  had 
considerable  practise  in  introspective  work. 

A  brief  description  of  the  poetic  fragments  employed 
seems  necessary.  The  descriptive  terms  used  are  taken  from 
those  given  by  the  reagents  in  connection  with  the  two 
groupings  of  the  fragments  made  by  them  on  the  basis  of 
their  emotional  vividness.  An  estimate  of  the  emotional 
value  of  each  fragment  was  obtained  by  adding  the  numbers 
of  the  groups  in  which  a  particular  fragment  was  placed  by 
each  of  the  seven  reagents  for  each  of  the  two  groupings. 
The  greatest  sum  obtainable  was  42;  the  least,  o.  The  sum 
actually  received  is  given  for  each  fragment  in  parenthesis 
after  the  descriptive  summary. 

The  fragments  were  as  follows:  i,  twelve  lines,  from 
Browning's  'Saul,'  expressive  of  the  joys  of  living,  beginning, 
'Oh,  our  manhood's  prime  vigor!'  (28);  2,  nine  lines,  verse 
XCIL,  Canto  Third,  Byron's  'Childe  Harold,'  descriptive 
of  the  exultation  and  awe  aroused  by  a  mountain  storm 
(33)j  3>  nine  lines,  verse  XXI.  of  Shelley's  'Adonais,'  expres- 
sive of  inevitability,  futility,  grief  (20);  4,  twelve  lines,  a 
lyric  expressive  of  companionship  (31);  5,  sixteen  lines,  the 
eleventh  verse  of  Swinburne's  'The  Garden  of  Proserpine,' 
with  an  emotional  toning  of  desire  for  death,  annihilation 
(17);  6,  ten  lines  from  Shelley's  'Prometheus  Unbound,' 
expressive  of  defiance,  beginning  'Fiend  I  defy  thee'  (29); 
7,  fifteen  lines  from  Browning's  'Andrea  Del  Sarto'  beginning 
'A  common  greyness  silvers  everything,'  lines  that  voice  a 
twilight  mood  of  sadness  and  resignation  (28);  8,  ten  lines,  a 
translation  by  Symons  of  one  of  Mallarme's  exquisite  word- 
pictures,  expressing  vague  aspiration,  calm  (13);  9,  nine  lines, 
fifth  stanza  of  Swinburne's  'A  Forsaken  Garden,'  expressive 
of  barrenness,  weariness  (19);  10,  eight  lines,  Stevenson's 
'Under  the  wide  and  starry  sky,'  completion  (23);  II,  twelve 
lines,  fifth  stanza  of  Browning's  'Love  Among  the  Ruins,' 


262  JUNE  E.  DOWNEY 

descriptive  of  expectancy  and  love  (25);  12,  fifteen  lines,  from 
Tennyson's  'The  Princess,'  'Tears  idle  tears'  (27);  13,  eight 
lines,  Galsworthy's  gay  wind-song,  'Wind,  wind — heather 
gypsy'  (25);  14,  eight  lines,  Blake's  'When  the  voices  of 
children  are  heard  on  the  green,'  expressive  of  quiet  happiness 
(17);  15,  twelve  lines,  Henley's  famous  'Captain  of  my  soul' 
verses  (34);  16,  thirteen  lines,  first  two  stanzas  of  Poe's  'To 
One  in  Paradise,'  voicing  despair  (27);  17,  sixteen  lines,  a 
descriptive  piece  by  Galsworthy,  'We'll  hear  the  uncom- 
panioned  murmur  of  the  swell,'  expressive  of  'God's  own 
quietude  of  things'  (24);  18,  seven  lines,  Yeats'  'Be  you  still, 
be  you  still,  trembling  heart,'  voicing  mystical  courage  (14); 
19,  eleven  lines  from  Tennyson's  'Lotus-Eaters,'  beginning 
'There  is  sweet  music  here  that  softer  falls,'  word-pictures 
suggesting  peace  (31);  20,  twelve  lines,  Marston's  'All  my 
roses  are  dead  in  my  Garden,'  expressing  despoilment,  hope- 
lessness (27);  21,  fifteen  lines,  the  hunger  for  pursuit  (16); 
22,  twelve  lines,  Yeats'  mystical  'Outworn  heart,  in  a  time 
outworn'  (14);  23,  nine  lines,  the  first  two  and  the  last 
stanza  of  Moody's  'Heart's  Wild-Flower'  (33);  24,  fourteen 
lines,  Moody's  'Grey  drizzling  mists  the  moorlands  drape' 
(23).  These  fragments  were  typewritten  on  separate  sheets 
of  paper,  convenient  for  handling.  The  poet's  name  did 
not  appear  on  the  fragment  and  only  a  few  cases  of  recognition 
occurred.  The  fragments,  except  4  and  21,  were  of  accepted 
literary  excellence,  many  of  them  being  classic  productions. 
On  the  basis  of  the  data  gathered  the  following  points 
may  be  discussed:  I.  The  variability  and  character  of  the 
group  preference  judgment  and  its  dependence  upon  such 
factors  as  the  emotional  content,  self-projection,  concrete 
imagery,  the  waxing  and  waning  value  of  the  separate  frag- 
ments; II.  The  variability  and  character  of  the  individual 
preference  judgment  and  its  dependence  upon  peculiarities 
in  the  individual  reactions;  III.  The  relation  of  the  preference 
judgment  to  the  judgment  of  beauty. 


POETRY  AND  THE  PREFERENCE  JUDGMENT  263 

I.  THE  GROUP  PREFERENCE  JUDGMENT 
The  average  position  of  each  fragment  for  each  of  the  five 
arrangements  by  the  seven  reagents  was  calculated  with  the 
average  M.V.  for  each  arrangement.  There  is  a  decrease  in 
the  average  M.V.  from  the  first  to  the  fifth  trial,  although 
not  a  constant  decrease,  as  follows:  first  trial,  4.839;  second 
trial,  4.535;  third  trial,  4.783;  fourth  trial,  4.629;  fifth  trial, 
4.166.  The  average  M.V.  for  the  first  arrangement  is  some- 
what high,  although  not  higher  than  that  given  in  certain 
other  reports  on  the  subjective  judgment.  It  is,  relatively 
to  the  number  of  possible  positions,  higher  than  the  average 
M.V.  in  a  first  arrangement  of  imaginal  poetry  on  the  basis 
of  pleasantness-unpleasantness.  It  is  tempting  to  attribute 
this  increased  M.V.  to  the  emotional  nature  of  the  poetry  and 
very  probably  it  should  be  so  attributed.  But  it  should 
not  be  forgotten  that  increased  subjectivity  is  not  the  only 
possible  cause  of  increased  variability. 

With  repetition  of  the  arrangements  there  is  lowered 
variability.  There  was  at  first,  as  has  been  pointed  out  by 
other  investigators  of  the  subjective  judgment,  a  greater 
agreement  on  the  unpreferred  fragments  with  a  shift  in  the 
last  three  trials  to  greater  agreement  on  the  preferred  frag- 
ments. The  average  M.V.  of  the  fragments  in  the  first  six 
positions  for  the  five  different  arrangements  is  as  follows: 
first  trial,  4.01;  second  trial,  4.62;  third,  4.04;  fourth,  4.22; 
fifth,  3.27.  The  greatest  agreement  is  seen  to  occur  on  the 
fifth  trial.  The  average  M.V.  for  the  fragments  in  the  last 
six  positions  should  also  be  noticed:  first  trial,  3.77;  second, 
3.94;  third,  4.53;  fourth,  4.52;  fifth,  4.41.  The  difference 
between  the  M.V.'s  for  the  first  and  the  last  six  positions  is 
greater  for  the  fifth  than  for  any  other  trial. 

The  increasing  agreement  of  the  group  with  repetition 
of  the  test  is  shown  by  the  extent  to  which  every  arrangement 
is  correlated  with  every  other  arrangement  as  given  in  Table  I. 
The  progressive  increase  in  coefficient  values  for  successive 
arrangements  is  evident,  reaching  a  final  value  of  .89  for  the 
last  two  trials. 


264 


JUNE  E.  DOWNEY 
TABLE  I 

CORRELATIONS  BETWEEN  GROUP-ARRANGEMENTS. 


Trial 

I 

II 

III 

IV 

V 

I.. 

.758 

.764 

•739 

•773 

II  

.758 

•75° 

.699 

.820 

Ill  

IV  

.764 
•739 

•75° 
.699 

.820 

.820 

.863 
.890 

v  

•773 

.820 

.863 

.890 

Av 

.7158 

.71:7 

.709 

.787 

8^7 

Study  of  the  records  suggests  no  explanation  for  this  other 
than  growing  objectivity  of  judgment  with  increased  famili- 
arity with  material.  With  such  familiarity  the  individual 
judgment  would  seem  to  be  steadied  by  social  standards. 

TABLE  II 

EFFECT  UPON  PREFERENCE  OF  VIVIDNESS  OF  EMOTION,  SELF-PROJECTION,  AND  IMAGERY 
(COMBINED  RECORDS.     7  REAGENTS). 


i 

2 

3 

4 

5 

6 

7 

8 

Totals 

Ill 

Emotion  —  I  
Self-projection.  .  .  . 
Imagery  
Emotion  —  2  
Total 

16 
25 
19 
13 

9 
9 
8 

7 

10 

6 
II 

7 

5 
3 
3 
i 

4 

2 

5 
5 

2 
2 
0 

2 

5 
i 

2 

I 

2 

4 

5 
7 

53 

52 

53 
43 

201 

II 

Emotion  —  I 

9 

12 

8 

7 

c 

6 

-I 

•i 

r-? 

Self-projection.  .  .  . 
Imagery 

5 
3 

6 

c 

4 

A 

5 
7 

3 
c 

7 

•2 

4 

1 

37 
•27 

Emotion  —  2 

IO 

7 

7 

I 

r 

•2 

4. 

46 

Total  

173 

I 

Emotion  —  I 

3 

2 

7 

2 

7 

7 

4 

36 

Self-projection.  .  .  . 
Imagery  
Emotion  —  2  
Total 

o 
3 

2 

4 
4 

10 

4 
3 

5 

3 

2 

6 

7 

2 

5 

3 
4 
5 

8 
9 

6 

5 
5 

30 
3i 
47 

\AA 

o 
Emotion  —  I  
Self-projection.  .  .  . 
Imagery 

0 

3 

•3 

i 
7 

IO 

i 

6 
8 

2 

6 

7 

4 
c 

i 

7 

3 
7 

9 
9 

2 

24 

49 

4.7 

Emotion  —  2       .  .  . 

2 

-j 

4. 

^ 

4 

c 

4' 

•32 

Total  

152 

An  attempt  was  made  to  determine  the  influence  of 
various  factors  upon  the  preference  judgment  by  obtaining 
as  described  above  a  four-fold  grouping,  twice  for  vividness  of 


POETRY  AND  THE  PREFERENCE  JUDGMENT 


265 


emotional  toning  and  once  each  for  vividness  of  concrete 
imagery  and  of  self-projection,1  and  distributing  these  judg- 
ments under  the  eight  preference  groups  (Table  II.). 

From  this  table  it  is  evident  that  the  three  factors  are 
about  equally  potent  but  that,  in  general,  rich  content, 
emotional,  imaginal,  and  self-projective,  contributed  to  pref- 
erence. The  figures  for  the  second  grouping  of  the  fragments 
on  the  emotional  basis  (fifth  preference  arrangement)  indicate 
some  loss  of  emotional  vividness  with  repetition. 

TABLE  III 


Five  Preference- 

Arrangement  for 

6/0 

Arrangements 

Beauty 

c 

•5, 

^ 

« 

£f 

c 

o 

g 

. 

o 

£ 

1 

o 

'i 

Emotional  Tone 

.  E 

0 

'55 

> 

> 

| 

>* 

. 

W 

C/3 

E 

E 
W 

* 

(S 

ai 

PH 

19 

I 

5.20 

3.20 

I 

1.85 

.98 

17 

15 

2O 

H 

Peace. 

23 

2 

6.08 

2.38 

3 

5-42 

2.03 

17 

15 

IS 

16 

Heart's  wild  flower. 

2 

3 

7-45 

2.86 

5 

6-57 

4.65 

18 

13 

19 

IS 

Exultation. 

17 

4 

8.05 

2.56 

2 

4-57 

2.94 

13 

15 

IS 

ii 

Quietude,  companionship. 

4 

5 

8-74 

3-44 

10 

11.28 

S.3I 

18 

9 

10 

13 

"You." 

ii 

6 

9.42 

2-54 

6 

6.7I 

3-10 

10 

12 

13 

IS 

"Love  among  the  Ruins." 

7 

7 

9.60 

5-20 

4 

6.57 

249 

12 

IS 

16 

16 

Twilight:  regret. 

IS 

8 

9.82 

3.00 

12 

14.00 

3-71 

19 

9 

6 

15 

Fortitude. 

i 

9 

9.85 

4.68 

7 

742 

I-SI 

16 

12 

12 

12 

Joy  of  living. 

24 

10 

12.50 

4.67 

14-57 

4.04 

13 

9 

IS 

10 

Weariness;  greyness. 

12 

ii 

12.85 

2.96 

8 

9.71 

3-75 

15 

ii 

7 

12 

"Days  that  are  no  more." 

22 

12 

12.91 

3-iS 

II 

11.71 

2.32 

10 

6 

9 

10 

Mystical  rebirth. 

IO 

13 

1342 

4.66 

17 

16.42 

5-35 

13 

12 

13 

10 

"Glad  did  I  live,  gladly  die." 

16 

13-51 

2-35 

13 

1442 

3.63 

14 

IO 

6 

14 

Despair. 

20 

IS 

14.48 

4-55 

18 

16.71 

6.33 

16 

12 

13 

II 

Hopelessness. 

8 

16 

15-17 

1.62 

9 

10.42 

S46 

6 

6 

ii 

7 

Aspiration. 

18 

17 

15.40 

3.20 

IS 

15.57 

4.20 

7 

5 

3 

7  IMystical  courage. 

S 

18 

15.42 

2.63 

21 

17-57 

346 

7 

7 

4 

10 

Eternal  sleep. 

13 

19 

15.54 

6.00 

22 

18.71 

3-55 

12 

12 

12 

13 

Irresponsibility. 

14 

20 

15.63 

3.07 

23 

18.57 

2.08 

8 

13 

9 

9 

Content. 

3 

21 

15.80 

3-54 

19 

16.85 

445 

12 

6 

4 

12 

Futility;  grief 

9 

22 

16.48 

16 

16.14 

4.12 

12 

ii 

9 

7 

Barrenness. 

21 

23 

17.82 

342 

2O 

17.14 

5-22 

9 

9 

12 

7 

Pursuit. 

6 

24 

18.77 

3-73 

24 

21.00 

2.OO 

13 

16 

II 

16 

Defiance. 

Table  III.  gives  the  position,  average  and  M.V.  for  every 
fragment,  for  five  preference  arrangements,  and  for  the  one 
arrangement  on  the  basis  of  beauty,  together  with  numbers 
representing  the  vividness  of  the  emotional,  self-projective, 
and  imaginal  reactions,  obtained  by  adding  together  the 

1  By  self-projection  is  meant  an  explicit  self-reference  in  whatever  form.  Cf. 
"Literary-Self  Projection,  PSYCHOL.  REV.,  19,  299-311  (1912). 


266 


JUNE  E.  DOWNEY 


number  of  the  groups  in  which  the  fragment  was  placed  by 
the  seven  reagents.  An  attempt  is  also  made  to  describe 
the  emotional  tone  of  each  fragment.  This  table  confirms 
the  conclusion  that  rich  content  contributes  to  preference 
but  suggests  also  that  imaginal  content  is  slightly  more 
potent  in  determining  preference  than  are  the  other  factors 
studied.  This  is  shown  also  by  grouping  together  the  six 
fragments  that  the  records  show  to  be  most  emotional, 
most  conducive  to  self-projection,  and  most  imaginal  with 
an  indication  of  the  position  of  each  fragment  in  the  preference 
series  (Table  IV.). 

TABLE  IV 


Most 
Emotional  i 

Position 

Most 
Emotional  2 

Position 

Most  Self- 
Projective 

Position 

Most 
Imaginal 

Position 

(1 

8 
3 

5 

u 

24 

7 

2 

6 

/.? 

24 
7 

4 

19 

2 

7 

I 

3 
7 

U? 

I 

2 

LI 

i 

IS 

2 
I 

(23 

1  17 

2 

4 

u 

9 
15 

III 

6 

{'i 

2O 

3 

U4 

10 

The  two  fragments  most  definitely  imaginal  (19  and  2)  rank 
respectively  first  and  third.  Many  fragments  occur  in  two 
or  more  of  the  groups. 

Putting  the  matter  in  another  way  we  see  that  of  the  six 
fragments  most  preferred  19  and  23  are  imaginal,  favor  self- 
projection,  and  are  emotionally  toned;  2  is  imaginal  and 
emotional;  17  is  imaginal,  and  induces  self-projection;  4  is 
emotional;  II  is  emotional,  imaginal,  and  favors  self-pro- 
jection. 

A  comparison  of  the  orders  received  by  the  different  frag- 
ments for  the  successive  arrangements  indicates  that  frag- 
ments 17,  n,  7,  24,  10,  8,  and  22  (slightly)  waxed  in  value; 
fragments  I,  16,  20,  13,  14,  and  4  (slightly)  waned  in  value; 
fragments  19,  23,  3,  9,  21,  6,  2,  12,  15  remained  relatively 
static;  fragment  18  waxed  in  value  and  then  fell;  5  waned 
and  then  waxed  in  value.  Reference  to  the  waxing  and 
waning  value  of  the  fragments  will  occur  later  in  discussion 
of  the  arrangement  on  the  basis  of  beauty. 


POETRY  AND  THE  PREFERENCE  JUDGMENT  267 

II.   THE  INDIVIDUAL  PREFERENCE  JUDGMENT 

The  effect  of  the  individual  reactions  upon  the  preference 
judgment  was  evident  and  makes  necessary  a  summary 
statement  of  certain  characteristics  of  the  reagents.  There 
were  seven  of  these  reagents  as  stated  before.  The  conclu- 
sions, relatively  to  their  general  reactions,  are  based  upon 
extensive  acquaintance  with  the  observers  in  psychological 
experimentation. 

With  reference  to  imaginal  tendencies  the  observers  fell 
into  three  groups. 

The  first  group  includes  reagents  Rgr  and  Ele,  subjects 
in  whom  there  is  a  strong  preponderance  of  visual  imagery. 
Rgr's  visual  images  are  vivid  and  detailed.  Ele  shows  a 
strong  inclination  to  emphasize  form;  she  is  accustomed  to 
changing  all  sounds  into  visual  forms.  Voices  she  pictures 
in  series  of  waves  and  lines  at  different  levels;  she  compares 
different  pitches  by  reference  to  the  heights  at  which  the 
translating  lines  are  placed.  She  has  a  great  liking  for 
mathematics. 

The  second  group  includes  Jan,  Hne,  and  Jdo.  These 
subjects  show  mixed  imagery.  Although  they  employ  visual 
imagery  to  some  extent,  they  appear  to  be  much  more  de- 
pendent upon  kinsesthetic  and  organic  material.  Auditory 
content  is,  however,  very  potent  for  Hne. 

The  third  group  includes  Ado  and  Tbu,  who  are  strikingly 
deficient  in  visual  imagery,  an  incapacity  which  in  Tbu's  case 
is  evidently  conditioned  by  very  poor  eyesight.  Tbu  relies 
almost  wholly  upon  inner  speech  and  is  strongly  inclined  to 
accept  the  imageless  thought  proposition.  Ado  makes  much 
use  of  kinsesthetic  material  and  in  this  respect  might  more 
properly  be  classed  with  the  second  group. 

The  form  which  self-projection  assumed  was  also  some- 
what characteristic  within  the  same  groups. 

For  Rgr  and  Ele  such  self-reference  appeared  to  be  highly 
objective.  Rgr  projects  herself  visually  within  the  scene 
but  without  dramatic  or  kinaesthetic  participation  in  the 
scene.  Ele  is  "there"  as  a  spectator  only.  She  assumes, 
without  visualization  of  self,  a  definite  orientation  toward  the 


268  JUNE  E.  DOWNEY 

scene,  always  on  the  outskirts,  where  she  is  able  to  get  a 
good  view  of  the  situation. 

For  Hne  and  Ado,  the  self-reference  is  highly  colored. 
Hne  gives  a  visual  self-projection  that  is  fused  with  kinsesthe- 
tic  and  organic  material;  she  is  within  the  scene.  Ado  is  also 
within  the  scene,  part  of  it,  but  without  visualization  of  self. 
Her  participation  is  definitely  dramatic,  emotional.  These 
two  reagents  "subjectify"  the  poetic  material. 

Jan  and  Jdo  identify  themselves  kinsesthetically  or  organ- 
ically with  persons  or  inanimate  objects  described.  Some- 
times for  Jdo  there  is  a  projection  of  kinaesthesis  into  a 
visualized  figure,  not  of  self.  As  distinguished  from  Hne 
and  Ado,  these  reagents  appear  to  project  or  objectify  the 
subjective  reaction. 

Tbu  reports  little  self-reference  except  that  in  inner  speech 
he  is  at  once  speaker  and  listener. 

A  grouping  on  the  basis  of  the  inner  speech  effects  some 
changes  in  the  distribution  of  subjects.  This  inner  speech 
is  auditory  for  Hne,  Tbu,  Jdo,  Ado,  and  Rgr.  But  of  these 
reagents  Hne  is  the  only  one  who  heard,  to  any  extent, 
fragments  read  in  voices  other  than  her  own.  Tbu,  Ado,  and 
Jdo  make  much  of  inner  elocution,  and  Tbu  is  almost  wholly 
preoccupied  with  this  aspect  of  the  reaction. 

Ele  and  Jan  were  sceptical  as  to  auditory  content  for  their 
inner  speech.  Ele  reported  again  curious  translations  of  the 
inner  speech  into  visual  forms. 

The  average  (with  M.V.)  was  calculated  for  each  frag- 
ment for  the  five  arrangements  by  each  reagent  and  the 
position  assigned  each  fragment  on  the  basis  of  this  average. 
The  average  M.V.  for  each  reagent  from  the  average  of  his 
five  arrangements  was  calculated  and  gives  us  an  indication 
of  his  individual  variability.  His  average  M.V.  from  the 
average  group  judgment  was  also  determined  and  this  indi- 
cates the  extent  to  which  his  judgment  was  representative 
of  the  group. 

The  variability  of  each  reagent  from  his  own  average  for 
the  five  trials  was  as  follows  in  the  order  of  least  variability: 
(i)  Tbu,  2.21 ;  (2)  Rgr,  2.28;  (3)  Ado,  2.71;  (4)  Ele,  3.11; 


POETRY  AND  THE  PREFERENCE  JUDGMENT 


269 


(5)  Jdo,  3.71 ;  (6)  Jan,  3.56;  (7)  Hne,  4.09.  Increased  varia- 
bility seems,  in  general,  to  characterize  the  more  emotional 
reagents  (determined  by  their  fourfold  grouping  of  the  frag- 
ments), while  the  effect  of  the  emotional  material  in  increasing 
the  variability  is  shown  by  comparison  of  the  individual 
variability  in  this  test  with  that  found  when  less  emotional 
poetry  was  utilized;  it  is  proportionately  much  higher  in  the 
present  test.1 

The  average  variability  of  each  reagent  from  the  average 
of  the  seven  reagents  for  the  five  arrangements  gave  the 
following  order:  (i)  Jdo,  2.75;  (2)  Ado,  2.90;  (3)  Rgr,  2.96; 
Ele,  3.07;  (5)  Jan, ^3.48;  (6)  Hne,  3.78;  (7)  Tbu,5.i9.  The 
most  interesting  point  in  this  listing  of  reagents  is  Tbu's  shift 
in  position,  which  with  high  personal  consistency  indicates 
a  different  basis  of  judgment  from  that  of  the  other  reagents, 
explanation  for  which  is  to  be  found  in  his  introspective 
reports.  On  the  whole,  it  may  be  noted,  the  variability 
from  the  group  average  is  no  more  extensive  than  that  found 
in  imaginal  poetry. 

TABLE  V 

PREFERRED  FRAGMENTS 


Rgr 

Ele 

Hne 

Jan 

Ado 

Jdo 

Tbu 

I 

19 

17 

II 

4 

19 

19 

15 

2 

2 

23 

4 

13 

17 

23 

I 

3 

7 

19 

12 

23 

7 

7 

2 

4 

23 

2 

19 

19 

23 

17 

10 

5 

I 

7 

I 

18 

2 

10 

24 

6 

4 

24 

13 

17 

II 

4 

5 

An  arrangement  in  order  of  the  six  fragments  which  were 
most  preferred  by  each  of  the  reagents  shows  at  once  the 
effect  of  the  individual  differences  in  reaction  (Table  V.). 
We  note  that  of  Rgr's  preferred  fragments,  the  first  four 
are  exactly  in  the  order  of  imaginal  vividness,  largely  visual. 
Rgr  states  very  definitely  that  she  prefers  poetry  which  calls 
up  vivid  visual  images,  unless,  as  in  fragments  13,  such  images 
are  grotesque.  Ele's  six  preferred  fragments  are  just  the  six 

1  A  great  variability  from  her  own  average  in  the  judgments  on  emotional  poetry 
in  contrast  to  great  self-consistency  in  judgments  on  imaginal  poetry  was  shown  very 
definitely  by  the  one  reagent  (Jdo)  who  participated  in  both  tests. 


zyo 


JUNE  E.  DOWNEY 


most  imaginal  fragments,  although  not  in  the  exact  order  of 
the  group.  Ele  also  expresses  a  preference  for  poetry  con- 
veying the  clearest  imagery  and  is  particularly  pleased  with 
what  she  calls  sound-pictures. 

Hne's  preferred  fragments  are  chiefly  emotional  in  tone; 
1 1  and  4,  both  highly  emotional,  represent  her  first  and  second 
choice.  Jan's  preferred  fragment  is  4,  which  is  emotional  in 
its  appeal,  but  his  other  choices  give  some  indication  of 
dependence  upon  imaginal  richness.  He  also  prefers  18,  a 
mystic  fragment  of  little  sensuous  content.  Ado's  and  Jdo's 
preferred  fragments  show  the  influence  of  imaginal  content 
as  well  as  of  emotional  toning. 

Tbu's  preferences  are  distinctly  individual,  determined 
largely  by  the  kind  of  emotion  expressed  which  Tbu  prefers 
to  be  strong  in  nature,  expressive  of  a  desire  to  act,  to  conquer. 
Neither  19  nor  23,  so  generally  preferred  by  other  reagents, 
occur  among  his  first  six  fragments;  the  absence  of  imaginal 
fragment  is  very  evident. 

TABLE  VI 

CORRELATIONS  OF  Av.  REFERENCE  ARRANGEMENT  OF  EACH  REAGENT  WITH  THAT  OF 
EVERY  OTHER  REAGENT 


Reagent 

Rgr 

Ele 

Jdo 

Jan 

Hne 

Ado 

Tbu 

Rgr  

.601 

•590 

.46l 

.232 

.700 

•237 

Ele  

.601 

410 

•325 

.209 

.702 

.103 

Jdo  
Jan  

.590 
.461 

410 
.325 

.536 

•536 

.230 
.256 

.569 
.241 

.200 
-.272 

Hne  

.232 

.209 

.230 

.256 

.38l 

-•059 

Ado  

.700 

.702 

.569 

.241 

.381 

•193 

Tbu  

•237 

.103 

.200 

-.272 

-•059 

•193 

The  tabulation  of  preferences  suggested  the  working  out 
of  the  coefficients  of  correlation  for  the  average  preference 
arrangement  of  each  reagent  with  every  other.  These  are 
given  in  Table  VI.  It  is  evident  from  this  table  that  re- 
actions on  the  basis  of  imaginal  qualities  are  most  representa- 
tive (Rgr,  Ado,  Jdo,  Ele)  and  that  the  subject  most  visual  in 
reaction  (Rgr)  gives  the  highest  average  correlation.  Should 
such  a  conclusion  be  substantiated  by  a  more  extensive 
investigation  it  would  seem  to  throw  light  upon  the  kind  of 


POETRY  AND  THE  PREFERENCE  JUDGMENT  271 

literary  material  that  would  probably  have  constant  value 
for  a  long  period  of  time  and  the  type  of  critic  that  would 
best  represent  the  average  reaction  in  the  long  run. 

Certain  other  factors  influencing  the  individual  reactions 
are  evident  from  the  tables  and  the  introspective  reports. 
Table  III.  indicates  that  subdued  emotions  are  more  generally 
preferred  by  this  group  than  are  violent  emotions.  The 
individual  reports  confirm  this,  although  the  effect  of  the 
mood  of  the  day  is  mentioned  by  several  reagents  as  influenc- 
ing their  preferences. 

Rgr.  "In  poetry  the  emotional  appeal  which  I  prefer 
depends  largely  on  my  mood. — I  like  poems  about  nature 
as  they  arouse  emotions  outside  of  one's  self." 

Ele.  "An  appeal  to  quiet,  drowsy,  lesiurely,  reminiscen- 
tial  feelings  suits  me  best. — I  do  not  like  noise,  boisterousness, 
confusion." 

Hne.  "The  appeal  preferred  depends  upon  the  mood. 
Usually  prefer  something  expressing  longing  unfulfilled,  or 
the  joy  of  living." 

Jan.  "I  do  not  know  that  I  can  select  any  one  emotional 
appeal;  sometimes  it's  one  sort,  sometimes  another.  Pathos 
perhaps  makes  the  greatest  appeal." 

Jdo.  "I  prefer  the  emotional  tone  to  be  in  harmony 
with  my  mood  which  varies  strongly  from  day  to  day.  In 
general  I  prefer  a  sad  toning." 

Ado.     "I  like  an  emotional  appeal  that  is  melancholy  in 


tone." 


Tbu.  "I  prefer  a  strong  emotional  appeal  to  any  of  the 
pleasant  emotions  and  sometimes  to  those  generally  con- 
sidered unpleasant.  Usually,  however,  I  prefer  such  an 
appeal  to  emotions  as  are  aroused  by  fragments  I  and  15, 
feelings  of  desire  to  act,  conquer,  oppose  even  unconquerable 
forces.  The  reason  for  this  preference  so  far  as  I  can  judge 
is  that  such  emotions  are  not  common  in  me.  However 
much  I  may  consider  them  ideal,  I  do  not  possess  them.  It  is 
their  contrary  nature  that  appeals  to  me." 

In  order  to  test  specifically  the  effect  of  the  mood  of  the 
day  upon  the  reaction  to  strongly  emotional  poetry,  the 


272  JUNE  E.  DOWNEY 

following    tabulation    was   made    (Table    VII.).     The   seven 
fragments  most  melancholy  in  tone  were  selected,  3,  5,  9, 

12,  16,  20,  24;  three  of  happy  buoyant  coloring  were  chosen, 

13,  14,  i;  and  three  of  strong  aggressive  emotion,  2,  6,  15. 
Next,  record  was  made  from  the  introspective  notes  of  any 
cases  where  the  reagent  reported  strongly  depressive  moods 
at  the  time  of  the  experiment.     Eight  cases  of  this  occurred. 
The  effect  of  the  mood-dominance  was  then  determined  by 
subtracting  the  position  on  the  day  in  question  for  the  given 
fragment  and  the  given  reagent  from  the  average  for  that 
reagent's    five    arrangements.     A    minus    sign    indicates    in- 
creased preference  for  the  fragment  for  the  given  day;  a  plus 
sign  indicates  decreased  preference. 

The  table  would  seem  to  suggest  some  interesting  dif- 
ferences between  the  reagents  as  to  the  effect  of  mood  upon 
their  preferences.  Jan  and  Jdo  show  very  evidently  that  a 
mood  of  depression  increased  for  them  the  preference  for 
melancholy  poetry  and  in  Jdo's  case  very  considerably 
lowered  the  liking  for  buoyant  fragments.  The  effect  of  the 
mood  upon  fragments  2,  6,  15  is  less  constant.  Ado's  record 
indicates  a  general  lowering  of  values  under  depression,  with, 
In  a  few  cases,  added  appreciation  of  the  melancholy  frag- 
ments. Rgr  shows  less  effect  of  mood  upon  preference  than 
any  other  reagent,  and  that  effect  is  mainly  a  lowering  of 
values.  The  effect  of  depression  is  somewhat  variable  for 
Ele  and  Hne,  both  records  suggest  that  harmony  with  the 
mood  is  likely  to  increase  preference.  Under  the  influence  of 
the  given  mood  these  reagents  show  inclination  to  stress  2 
and  6.  The  effect  of  mood  upon  the  emotional  reaction 
is  a  very  important  one.  The  above  discussion,  however 
meager,  suggests  a  method  by  which  the  problem  may  be 
attacked. 

Jdo's  comments  on  the  effect  of  mood  upon  the  reaction 
for  any  particular  day  are  more  complete  than  those  of  the 
other  reagents  and  in  certain  respects  instructive.  There 
were  days  of  aesthetic  toning  and  other  times  when  it  required 
considerable  effort  to  surrender  to  poetic  suggestion.  These 
differences  were  due  to  general  mental  conditions,  rather 


POETRY  AND  THE  PREFERENCE  JUDGMENT  273 

than  to  experimental  conditions.  At  the  close  of  the  experi- 
ment Jdo  was  usually  in  a  more  aesthetic  mood  than  at  its 
beginning.  The  most  adverse  general  criticism  upon  experi- 
mental investigations  of  this  sort  she  finds  in  the  reduction 
of  the  time  needed  for  aesthetic  absorption.  Short  fragments 
suffer  in  comparison  with  the  longer  productions  from  which 
they  are  taken.  Fragment  12,  for  instance,  frequently  failed 
4  to  catch  fire.'  Rereading  was  necessary.  Again,  Jdo  noted 
that  the  first  fragments  suffered  by  being  read  before  she 
had  assumed  a  poetic  mood;  or,  at  times  of  increased  suscepti- 
bility to  outer  suggestion,  fragments  I  and  2  set  the  tone  for 
subsequent  reactions. 

The  second  arrangement  was  made  under  a  mood  of  great 
depression,  heightened  by  the  'grey  toning'  of  the  weather. 
Jdo  recorded  in  her  notes  that  fragments  expressive  of  sadness 
and  futility  were  given  a  higher  value  than  before.  She  was 
aware  also  of  a  tendency  to  react  against  the  mood  by  assign- 
ing high  value  to  fragments  expressive  of  fortitude.  At  the 
third  arrangement  a  mood  of  aesthetic  sadness  again  enhanced 
the  value  of  fragments  of  melancholy  tone.  On  this  occasion 
the  lilt  and  swift  mocking  rhythm  of  9,  14,  and  13  were  found 
very  distressing.  She  reports,  "They  move  too  rapidly  and 
lightly  to  fit  in  with  the  tempo  of  my  mood."  At  the  close 
of  the  test  the  pulse-rapidity  was  found  to  be  78.  The 
fourth  arrangement  was  made  when  the  subject  was  in  a 
scientific  mood  that  contrasted  strongly  with  the  aesthetic 
mood  of  the  previous  week;  there  was  restlessness  present 
and  distaste  for  taking  time  for  the  experiment.  The 
melancholy-toned  fragments  were  conspicuously  less  pleasing 
than  before.  Fragments  13  and  14  now  fitted  into  the  rhythm 
of  the  day  and  were  shifted  from  the  eighth  to  the  second 
group.  The  pulse  was  90.  The  fifth  arrangement  was  made 
under  the  influence  of  a  "hurry-mood"  (pulse  94);  Fragment 
13  was  felt  to  express  exactly  the  personal  tempo  for  the  day. 

Besides  investigating  the  influence  of  the  imaginal  and 
emotional  reactions  upon  preference,  the  experimenter  made 
an  attempt  to  determine  the  effect  upon  preference  of  the 
different  forms  of  the  inner  speech.  In  particular,  an  effort 


274 


JUNE  E.  DOWNEY 


was  made  to  determine  whether  certain  fragments  encouraged 
an  auditory  inner  speech  and  others  stressed  the  kinaesthetic 
quality  of  inner  speech.  To  this  end  the  reagents  were 
requested,  in  connection  with  the  third  preference  arrange- 
ment, to  place,  if  possible,  the  fragments  in  two  groups,  one 
group  being  for  fragments  in  which  the  auditory  aspect  was 
the  more  pronounced  in  the  inner  speech,  the  other  for  frag- 
ments that  stressed  the  kinaesthetic  factor.  The  attempt 

TABLE  VII 

EFFECT  OF  MOOD  ON  PREFERENCE 


Mood  Reagent 

Arrangement 

ISt 

Dis- 
gusted 
Jan 

ISt 

De- 

pressed 
Ado 

3d 
"Blue" 
Ado 

2d 
Sad 
Jdo 

Dl 
pressed 
Jdo 

D3i 

satisfied 
Rgr 

4th 
Im- 
patient 
Ele    . 

5th 
Dis- 
heart- 
ened 
Hne 

No.  of  Frag. 
3.  Futility  Grief. 

—  6.2 
—10.8 
-3-8 

+  1.6 

—  3-2 
—  8.8 

—   1.2 

+6.8 

±1.6 
+tt 

—  O.2 

+  2.2 

—9.2 
—6.0 
+  1-4 

+  1.8 

+2.2 
—6.2 
+5-2 

-4-6 

—  6.2 

-7.8 

—   I.O 

+  2.4 

+  1.4 
—i  i.  6 

-3-6 

—   3-2 

+    2.2 

~5'? 

—  3-6 
-3-6 
—  0.6 

—4.2 

o.o 
—44 

+3-0 
+  1.4 

+  2.0 

+34 

+    1.2 

—  3-2 
—  i.o 

-9-6 

+  0.6 
+  4-2 
—  1.6 

+   54 
—   2.8 
—  4.4 

—  3-o 
+  1.8 
+  0.8 
+  1.8 

5.  Eternal  Sleep 

o    Barrenness 

12.  "Days    that    are    no 
more"  

16.  Despair  

20.  Hopelessness  

24.  Weariness  

13.  Gavetv  . 

—  3-2 
—  4.2 
+   8.2 

+0.8 
—0.8 
+1.8 

—  1.2 

+0.2 
—0.2 

+   2.6 

+  3-0 
+  5-6 

+  11.6 
+  9-o 
+  6.6 

—0.4 

+2.8 
0.0 

+  3-2 

—   2.8 

—  3.2 

+  6.0 
+  0.8 

+  12.2 

14.  Happiness 

i.  Joy  of  living   . 

2.  Exultation 

—  0.6 
+  2.6 
-5.8 

+  1.6 
+  1.6 
+6.4 

+4-2 

+  1.6 

-4.6 

+  8.6 
—  2.8 
—  8.0 

T  2 

o.o 

—  O.2 

—0.6 

—  3-2 

—15.0 

+   0.2 

—10.4 

—  8.0 

+   2.0 

6.  Defiance 

15.  Fortitude 

proved  abortive,  although  the  comments  upon  the  variations 
of  the  inner  speech  were  instructive.  Only  two  reagents 
(Tbu  and  Jdo)  were  willing  to  attempt  the  grouping  suggested. 
Tbu's  choice  of  fragments  in  which  the  auditory  side  was 
most  stressed  was  as  follows:  5,  8,  9,  10,  12,  13,  14,  16,  19, 
20,  21.  Jdo's  selection  was  as  follows:  4,  10,  12,  13,  14,  19. 
There  are  five  fragments  selected  by  both  of  these  reagents. 
Fragment  21  was  written  in  dialogue  form,  the  two 
speakers  being  a  mother  and  son.  Nearly  all  the  reagents 
note  a  difference  in  inner  speech  with  the  transition  from 
one  part  to  another.  Hne  hears  her  own  voice  for  the 


POETRY  AND  THE  PREFERENCE  JUDGMENT  275 

mother's  part,  and  a  man's  deep  voice  for  the  son's.  She 
finds  the  fragment  pleasing.  Tbu,  on  the  other  hand,  who 
hears  the  man's  voice  in  his  own,  and  the  mother's  voice  in  a 
squeaky  disagreeable  voice,  does  not  like  the  fragment. 

Ele  reported  that  she  seemed  to  see  the  inner  speech. 
"Inflections  are  represented  by  different  levels  upon  a  scale." 
For  Jdo,  there  was  a  prominence  of  the  visual  verbal  side 
(with  subordination  of  the  inner  speech)  for  fragments  4,  9, 
13,  and  17.  These  two  subjects  are  the  only  ones  referring 
to  visual  factors  in  connection  with  the  inner  speech. 

III.  THE  PREFERENCE  JUDGMENT  AND  THE  JUDGMENT  OF 

BEAUTY 

The  introspective  reports  of  the  reagents,  except  those  of 
Tbu  and  Hne,  do  not  indicate  much  difference  in  their  basis 
of  judgment  when  they  shift  from  the  category  of  preference 
to  that  of  beauty.  Ele  and  Rgr  assert  that  there  is  no  differ- 
ence introspectively  between  the  two  forms  of  judgment. 
Rgr  adds,  "I  would  not  prefer  those  fragments  which  did  not 
appeal  to  me  as  beautiful."  Jdo  makes  the  preferred  frag- 
ments largely  correspondent  with  the  beautiful  ones  although 
she  reports  that  there  may  be  poetry  which  is  merely  pleasing 
and  preferred  for  that  reason.  Ado  finds  little  difference 
between  the  two  categories,  except  that  in  a  preference 
arrangement  she  gives  more  attention  to  the  thought  and 
in  the  beauty  arrangement  more  attention  to  style  and  form 
of  expression.  Hne  reports  considerable  difference  between 
the  two  kinds  of  arrangement.  She  also  emphasizes  the 
expression-side  as  important  for  the  judgment  of  beauty  and 
the  thought-side  as  important  for  preference.  Tbu  makes 
the  following  distinction,  "By  beautiful  I  mean  a  fragment 
that  is  pleasing  in  rhythm,  rhyme,  and  meaning.  Preference 
is  based  on  the  emotional  reaction." 

Some  differences  are  given  as  to  the  emotional  appeal  that 
seems  most  beautiful  in  comparison  with  that  which  is 
preferred.  Ele,  Rgr,  and  Ado  find  no  difference  Ele  states 
that  an  appeal  to  quiet  drowsy  emotions  is  at  once  most 
preferred  and  most  beautiful;  Rgr  finds  an  appeal  to  peaceful 


276  JUNE  E.  DOWNEY 

emotions  most  beautiful;  so,  too,  does  Jan.  Jdo  writes,  "I 
feel  the  appeal  to  renunciation,  to  world-sadness,  to  wistful- 
ness,  to  serenity  most  beautiful."  And  Tbu,  "A  lack  of 
emotional  appeal  seems  most  beautiful  to  me;  something 
calm,  quiet,  not  at  all  exciting."  Throughout  the  group 
there  is  evident  a  tendency  to  reduce  the  value  of  personal 
emotion  as  a  factor  in  the  judgment  of  beauty.1 

Correlation  of  the  average  arrangement  by  the  seven 
reagents  on  the  basis  of  beauty  with  the  average  on  the  basis 
of  preference  (five  trials)  is,  however,  very  high,  .894.  A 
correlation  of  this  average  judgment  for  beauty  with  the 
average  of  the  first  and  the  fifth  preference  arrangement 
gives  as  coefficients  .729  and  .941  respectively.  This  last 
coefficient  may  indicate  merely  that  the  growing  agreement 
of  the  group  shown  in  the  correlation  of  successive  arrange- 
ments for  preference  (Table  I.)  continued  in  spite  of  the  shift 
in  category  and  the  lapse  of  four  weeks;  or,  more  probably, 
it  shows  that  with  familiarity  with  the  fragments  preference 
is  determined  more  definitely  by  the  element  of  beauty  than 
is  evident  in  the  earlier  trials.  A  preliminary  arrangement 
for  beauty  would  have  been  most  valuable  in  this  connection. 

The  average  M.V.  for  the  arrangement  on  the  basis  of 
beauty  is  3.61,  a  lower  M.V.  than  found  for  any  of  the  five 
preference  arrangements.  This  lowered  M.V.  suggests  a 
more  objective  standard  for  the  judgment  of  beauty  than 
for  a  judgment  of  preference.2  Tbu,  in  particular,  shifts 
his  basis  of  judgment.  The  correlation  coefficient  for  his 
arrangement  on  the  basis  of  beauty  with  the  average  of  the 
group  is  high,  .783. 

In  particular,  it  seems  probable  that  a  beautiful  fragment 
is  more  constant  in  its  value  than  a  preferred  one  and  falls 
less  in  value  with  familiarity  in  the  repeated  arrangements. 
There  are  several  ways  in  which  one  may  test  this  assumption. 
One  may,  for  instance,  inspect  the  order  of  fragments  in  the 
first  preference  arrangement  (group  average)  and  note  which 
fragments  show  striking  discrepancies  with  the  order  of 

1  This  report  is  quite  in  accord  with  Souriau's  conclusion.     "  La  Reverie  Esthetique," 
p.  104  f. 

2  Compare  Miiller-Freienfels,  R.     "Psychologic  der  Kunst,"  II.,  p.  171. 


POETRY  AND  THE  PREFERENCE  JUDGMENT  277 

fragments  in  the  arrangement  for  beauty  (group  average) 
One  might  then  check  this  list  with  the  numbers  of  those 
fragments  that  have  already  been  cited  as  showing  evidence 
of  a  waxing,  waning,  or  static  value  in  the  repeated  preference 
arrangements.  Following  this  out,  we  find  that  fragments 
4,  13,  14,  15,  1 6  and  20  give  a  much  higher  value  (five  or  more 
places)  in  the  first  preference  arrangement  than  in  the  arrange- 
ment for  beauty.  With  one  exception  (15)  these  are  just  the 
fragments  which  were  found  to  fall  in  value  with  the  repeated 
arrangements.  Fragments  7,  8,  9,  12,  and  17  show  a  much 
higher  value  in  the  arrangement  for  beauty  than  in  arrange- 
ment for  preference.  Three  of  these  fragments  7,  8,  and  17 
were  fragments  that  waxed  in  value  with  the  repeated 
arrangements.  The  outstanding  fragments  are  instructive. 
Fragment  15  is  very  definitely  a  preferred  fragment  rather 
than  a  beautiful  one;  fragments  9  and  12  are  judged  to  be 
beautiful  but  in  spite  of  that  are  not  highly  preferred. 

Again,  taking  the  average  arrangement  for  beauty  and 
dividing  it  into  two  sections,  the  twelve  fragments  least  and 
the  twelve  fragments  most  beautiful,  we  find  that  of  the 
twelve  most  beautiful  fragments,  five  were  those  which 
waxed  in  value  in  the  preference  arrangements,  five  were 
static  in  value,  two  waned  in  value.  Of  the  twelve  less 
beautiful  fragments,  three  fell  in  value  in  the  preference 
arrangements,  five  were  static,  two  waxed,  two  (18  and  5) 
fluctuated. 

The  conclusion  seems  justified  that  the  beautiful  has  a 
value  which  holds  its  own  or  waxes  with  familiarity.1 

IV.    SUMMARY  AND  CONCLUSIONS 

As  a  general  outcome  of  the  experiment  we  conclude  that 
the  group  reaction  to  emotional  poetry  is  slightly  more  sub- 
jective than  the  group  reaction  to  imaginal  poetry.  Famil- 
iarity with  the  material  reduces  the  group  variability.  Rich 
content,  emotional  and  imaginal,  is  shown  to  contribute  to 
preference,  with  a  slight  advantage  in  favor  of  imaginal 
content  as  a  determining  factor.  Certain  fragments  appear 
1  Miiller-Freienfels,  op.  cit.,  II,  p.  168. 


278  JUNE  E.  DOWNEY 

to  fall  in  value  with  repetition  of  the  judgment;  others  to 
increase;  others  are  static. 

The  effect  of  individual  differences  upon  preference  is  so 
evident  that  a  grouping  of  the  reagents  on  the  basis  of  type  of 
reaction  is  instructive.  The  more  emotional  subjects  appear 
to  be  more  variable  in  their  judgments.  The  preferences  of 
four  of  the  reagents  show  a  great  dependence  upon  imaginal 
content;  emotional  vividness  is  potent  for  two  subjects;  and 
kind  of  emotional  content  for  one.  The  intercorrelations 
indicate  that  preferences  based  on  imaginal  content  have  a 
more  representative  value  than  preferences  determined  by 
emotional  content.  The  latter  are  influenced  by  the  mood 
present  at  the  time  of  choice. 

A  group  arrangement  on  the  basis  of  beauty  correlates 
very  highly  with  the  average  group  preference  arrangement 
and  would  seem  to  be,  for  most  of  the  observers,  determined  in 
much  the  same  way.  This  second  judgment  is,  however,  less 
subjective  than  the  preference  judgment.  Apparently  the 
more  beautiful  fragments  have  a  more  constant  value  than 
fragments  that  are  merely  preferred.  Since  the  former  do 
not  wane  in  value  as  do  the  latter,  in  time  the  two  categories 
closely  approximate  each  other. 

In  general,  the  order  of  merit  method,  in  conjunction  with 
an  analysis  of  individual  reports,  appears  to  afford  a  most 
excellent  means  of  studying  the  aesthetic  reaction. 


AN   EXPERIMENT   IN  ASSOCIATION 

BY  C.  G.  BRADFORD 

East  Central  State  Normal,  Ada,  Oklahoma 

THE  method  used  in  this  experiment  was  devised  by  Dr. 
J.  E.  Lough,  of  New  York  University.  It  is  simple  and  easy 
to  execute,  and  at  the  same  time  it  is  very  effective.  The 
experiment  is  dominantly  mental  in  character. 

i.   AIM 

This  experiment  was  studied  in  the  light  of  the  influence 
of  (a)  practise,  and  (b)  such  transient  factors  as  distraction, 
fatigue,  concentration,  state  of  health,  etc. 

2.   METHOD  AND  MEANS 

The  experiment  was  conducted  individually,  the  writer 
being  the  subject.  The  means  used  were  the  test  and  key 
sheets  of  the  Lough  Association  Method.  Other  means  were 
a  common  lead  No.  2  pencil  and  paper  to  write  the  associated 
letters  on.  Time  was  kept  by  an  ordinary  watch. 

The  test  sheet  contained  ten  rows  of  letters;  each  row 
contained  twenty  letters.  These  letters  were  in  non-alpha- 
betic order.  The  key  sheet  had  two  rows  of  letters  on  it, 
one  just  above  the  other.  The  top  row  was  in  alphabetic 
order,  from  A  to  T,  inclusive.  The  bottom  row  was  placed 
in  random  order  and  each  of  its  letters  was  directly  under  a 
letter  of  the  top  row.  For  convenience  a  test  sheet  and  keys 
have  been  inserted.  On  this  sheet  seven  keys  are  given, 
the  first  in  full,  but  as  the  top  row  is  the  same  for  all  keys 
only  the  bottom  row  of  each  of  the  others  is  given. 

3.    PROCEDURE 

This  experiment  was  taken  in  three  divisions.  The  morn- 
ing test  (A)  was  taken  between  seven  and  eight  o'clock,  with 
emphasis  on  speed,  i.  e.,  it  was  quantitative  in  nature.  The 

279 


280  C.  G.  BRADFORD 

afternoon  test  (J5)  was  taken  between  one  and  two  o'clock, 
and  was  qualitative  in  nature,  the  emphasis  being  put  on 
the  quality  of  the  work  rather  than  speed.  The  evening 
test  (C)  was  taken  for  both  speed  and  accuracy  and  came 
between  ten  and  eleven  o'clock.  The  general  course  of  these 
three  tests,  except  the  aspects  already  described,  was  the 
same  in  all. 

TEST  SHEET 

KCENORAFB  ILGSMPTDJHQ 
MKNGOLCAEBT  IFQ  JPHRDS 
CDATG  I  SKRN  JMQSEHOPLF 
QTCPF  JNL  ICDRG  SAEKHBM 
TPHM  JNL  SOFDGEQLKANB  I 
N  IBQEHDTJRFAKSLOGMCP 
AQ  IKEGT  S  JDOHCFMBRLPN 
SAPJQMGDFTRK  INHLEOCB 
JE  IBDNGSOCMLAQFRPTKH 
GNEDKB  SRQHPC  JLTMFAO  I 

KEYS  USED 

i 
ABCDEFGH  I  JKLMNOPQR  ST 

UYTMB  JCZCLYKAEGF  IHND 
TMH  IA  SCBXDE  JFYWGOKUL 
SXYKN  JUPTP  E3C  OQRADEZL 
MTJODPVAYC  F4B  SQEWGNHM 
ZUFLYMBWZER5DHAVJNG  IO 
CPGQKTAXUNYOJFRLW  IMD 
FGX  JRWVLDMB7J  J  SCY  IKUZ 

Making  the  associations  of  the  letters  was  done  in  the 
following  manner:  The  key,  until  all  associations  were 
thoroughly  committed  to  memory,  was  kept  just  above  the 
line,  on  the  test  sheet,  on  which  the  subject  was  working. 
The  letters  in  each  line  of  the  test  sheet  were  taken  consecu- 
tively as  they  were  approached,  regardless  of  their  order. 
Each  one  was  matched  with  its  likeness  in  the  upper  row  on 
the  key,  and  under  it  was  written  the  particular  letter  which 
appeared  under  its  likeness  in  the  top  row  of  the  key,  e.  g., 
A  was  first  in  the  top  row  on  the  key:  suppose  that  under  A 
in  the  bottom  row  of  the  key  was  Z,  then  whenever  A  was 


AN  EXPERIMENT  IN  ASSOCIATION  281 

found  in  a  line  on  the  test  sheet  Z  was  written  under  it. 
For  further  illustration  take  an  actual  case.  On  the  test 
sheet  K  is  the  first  letter  in  the  first  line;  by  running  down 
the  top  row  of  letters  on  the  key  (No.  i)  we  find  that  K  has 
Y  under  it;  therefore  we  would  write  Y  under  K  on  the  test 
sheet.  All  the  other  letters  are  associated  in  the  same  way 
with  the  various  letters  of  the  alphabet. 

These  associations  were  made  very  slowly  at  first.  The 
subject,  however,  soon  learned  a  few  of  the  associations  or 
equivalents,  and  learned  how  to  make  short  cuts  from  the 
letters  on  the  test  sheet  to  their  equivalents  in  the  key, 
without  going  to  the  first  of  the  key  and  following  it  letter 
by  letter  till  the  right  one  was  reached  as  the  tendency  at 
first  was  to  do,  and  thus  continually  decreased  the  time  for 
each  test.  As  these  associations  were  committed  to  memory, 
this  entire  process  of  referring  to  the  key  for  the  equivalent 
was,  of  course,  syncopated.  When  the  associations  became 
well  fixed  in  consciousness  the  sight  of  a  certain  letter  on  the 
test  sheet  brought  up  an  immediate  image  of  its  equivalent 
in  the  key  and  the  motor-writing  impulse  was  discharged, 
resulting  in  the  hand  movement  executing  the  writing  of  the 
equivalent. 

In  this  experiment  the  completion  of  a  test  sheet  consisting 
of  ten  lines  constituted  a  test,  one  of  the  ten  lines  constituted 
a  trial. 

Twenty  tests  were  made  in  each  key,  except  the  fifth, 
which  by  oversight  was  discontinued  after  nineteen  tests. 
When  one  key  was  finished  another  was  immediately  begun. 
Seven  keys  were  finished,  covering  a  total  of  one  hundred 
and  thirty-nine  days.  On  account  of  illness  one  test  was  missed 
in  both  the  morning  and  the  evening  series.  No  other  break 
occurred  in  the  entire  experiment. 

4.    RESULTS 

The  results  of  this  series  of  tests  are  very  interesting, 
especially  from  the  standpoint  of  practise,  and  the  effect  of 
changing  keys. 

Curves  are  plotted  and  tables  compiled  from  the  daily 


282 


C.  G.  BRADFORD 


AN  EXPERIMENT  IN  ASSOCIATION  283 

records.  These  curves  and  tables  show  concretely  and  graph- 
ically the  learning  process  or  habit  formation  in  this  experi- 
ment. 

The  tables  show,  for  each  key,  the  daily  record  in  seconds 
for  the  average  of  ten  trials,  or  one  test,  the  general  average, 
the  maximum  and  minimum  trials,  and  the  mean  variation 
for  twenty  tests. 

Curves  A,  B  and  C  represent  the  daily  series  of  experi- 
ments as  heretofore  explained.  Curve  D  represents  the  mean 
variations  in  the  various  keys  and  for  the  three  series.  This 
curve  shows  that  in  each  succeeding  key  the  mean  variation 
became  smaller  and  smaller. 

The  subject  found  that  to  try  to  rush  either  in  getting 
adjusted  in  order  to  start  at  a  given  time,  e.  g.,  when  the 
second  hand  of  the  watch  reached  the  thirty  seconds  mark, 
or  to  finish  a  trial  in  a  shorter  period  than  the  previous  one 
nearly  always  resulted  in  a  loss  rather  than  a  gain  in  time. 
It  seemed  that  consciousness  rebelled  against  any  acts  of 
coercion.  Usually  when  the  best  records  were  made  the 
process  was  almost  unconscious,  i.  e.,  no  special  effort  for 
speed  was  being  made. 

Some  associations  in  each  key  were  easily  made  because 
of  their  familiarity.  That  is,  they  formed  initial  letters  of 
familiar  names  and  for  that  reason  were  easily  remembered. 
After  these,  the  associations  of  the  first  and  last  letters  with 
their  equivalents  were  the  easiest  to  form.  The  remaining 
associations  then  were  retained  by  sheer  memory. 

At  times  it  was  very  hard  to  concentrate  the  attention, 
and  as  a  result  a  very  poor  record  was  made.  Many  times 
the  subject  wasted  time  in  trying  to  recall  a  certain  equivalent 
instead  of  looking  at  once  at  the  key. 

In  some  cases  the  sequence  of  letters  offered  resistance  to 
conscious  activity.  For  instance,  in  key  No.  I  Y  is  the 
equivalent  of  both  B  and  K,  and  it  happens  that  B  and  K 
come  together  in  the  last  line  of  the  test  sheet,  thus  causing 
two  Y's  to  come  consecutively  in  the  association.  In  this 
case  the  subject  had  a  feeling  when  writing  the  second  Y 
that  he  was  either  repeating  the  same  association  or  making 


284  C.  G.  BRADFORD 

a  false  association  which  caused  considerable  distraction.  In 
key  No.  7  the  letter  J  comes  twice  consecutively;  its  equiva- 
lents are  L  and  M;  it  happens  that  in  the  ninth  line  of  the 
test  sheet  the  letters  M  and  L  come  together,  thus  causing  a 
repetition  in  the  association  as  explained  above. 

The  subject  had  another  source  of  distraction  closely 
akin  to  that  mentioned  above,  namely,  making  a  second 
association  and  thus  writing  the  wrong  letter.  To  illustrate 
this  process  let  us  refer  to  key  No.  i;  D  in  the  top  line  has 
its  equivalent  M  in  the  bottom  line;  while  M  in  the  top  line 
has  its  equivalent  A  in  the  bottom  line;  when  the  key  became 
well  memorized  there  was  a  tendency,  upon  seeing  D,  to  run 
ahead  and,  instead  of  writing  its  equivalent  M,  to  write  M's 
equivalent  A.  This  difficulty  may  have  been  due  to  a  lack 
of  concentration  of  attention. 

It  was  also  found  that  a  cold,  fatigue  or  unaccustomed 
noise,  persons  entering  the  room,  knocking  on  the  door,  etc., 
caused  slow  work,  or  an  increase  in  the  time  record. 

The  form  of  the  curves  A,  B  and  C  is  very  striking.  Each 
one  of  these  composite  curves  contains  curves  of  the  seven 
keys  used.  The  broken  vertical  lines  between  these  curves 
are  merely  connections  and  have  nothing  to  do  with  the 
experiment. 

It  is  very  significant  that  in  these  curves  for  the  various 
keys  the  greater  part  of  the  gain  comes  during  the  first  day's 
practise.  For  instance,  in  curve  A,  key  No.  I,  the  total 
gain  was  32.5  seconds,  while  the  gain  of  the  first  day  was  13 
seconds.  In  key  No.  3  of  the  same  curve  the  total  gain  was 
28  seconds,  while  the  gain  for  the  first  day  was  20  seconds, 
thus  leaving  a  gain  of  only  8  seconds  during  the  remaining 
nineteen  days. 

For  the  most  part  the  key  curves  in  curves  B  and  C  make 
less  gains  than  those  in  curve  A.  This  is  due,  however,  not 
so  much  to  a  failure  in  reaching  low  minima  as  to  the  fact 
that  the  maxima  were  lower  than  those  in  curve  A.  This  was 
expected  because  of  the  practise  in  the  same  keys  in  curve  A. 
While  the  mental  attitude  was  different  and  while  the  aim  was 
not  identical  in  the  three  series,  nevertheless,  the  practise 


AN  EXPERIMENT  IN  ASSOCIATION  285 

had  the  same  effect  on  consciousness  and  the  habit-forming 
processes;  and,  therefore,  the  second  and  third  series  had 
the  benefit  of  the  practise  done  in  the  first  series. 

In  passing  from  one  key  to  another,  of  course  there  was  a 
considerable  rise  in  time.  It  has  been  contended  by  some 
authors  that  such  rises  in  changing  the  reaction  to  certain 
stimuli  are  caused  by  interference;  others,  Bair,1  for  instance, 
think  not,  unless  it  takes  longer  to  do  the  new  test  than  it 
did  to  do  the  preceding  one. 

It  seems  to  the  writer  that  there  are  two  possible  explana- 
tions: first,  if  the  time  taken  in  doing  the  new  experiment  is 
less  than  that  for  the  old  one  the  initial  rise  is  due  simply  to 
the  general  law  of  habit  formation  and  not  to  interference 
of  associations  formed  in  the  previous  habit.  Because  if 
such  interference  does  exist,  and  this  added  difficulty  plus 
the  normal  difficulty  in  forming  any  habit  be  fused  together, 
it  would  undoubtedly  take  a  longer  time  to  perform  the  new 
experiment  the  first  time  than  it  did  to  perform  the  old  one 
the  first  time;  and,  secondly,  it  is  probable  that  there  is,  on 
account  of  similarity  and  recency  when  two  experiments 
are  related  in  character,  a  certain  amount  of  interference 
which  would  tend  to  decrease  the  time.  It  is  also  probable 
that  a  certain  amount  of  the  learning  in  the  first  experiment 
is  transferred  to  the  new  one  which  would  tend  to  decrease 
the  time.  With  one  of  these  forces  tending  to  increase  the 
time  and  the  other  tending  to  decrease  it  a  resultant  is 
obtained  which  ordinarily  gives  as  a  consequence  a  lower 
time  record  than  occurred  in  the  former  experiment.  It 
seems  to  the  writer,  from  his  study  of  general  experimental 
findings  and  from  a  close  study  of  his  own  experiments  in  the 
learning  process,  that  the  latter  hypothesis  is  the  more 
tenable. 

5.    CONCLUSION 

In  this  experiment  we  have  the  typical  learning  process. 
This  process  is  made  graphic  by  curves  which  show  very 
rapid  progress  at  first,  but  finally  the  rate  becomes  very  slow. 

1  Bair,  J.  H.,  "The  Habit  Curve,"  PSY.  REV.,  Monog.  Suppl.,  1903. 


286 


C.  G.  BRADFORD 


TABLES  FOR  THE  SEVEN  KEYS 

AVERAGE  TIME  IN  SECONDS  FOR  EACH  TEST  OF  TEN  TRIALS 

Key  i  Key  2 


Date 

A 

B 

C 

Date 

A 

B 

c 

Oct.    22  
"      23  

45-5 

33.1 

48.5 

3C.2 

37-4 
26.8 

Nov.  ii  

"        12  

38.2 

26.7 

30.9 

3O  C 

33-8 
26  i 

"     H 

jj'j 
26.1; 

31.3 

26.4 

"      13 

2C   A 

066 

27  C 

'"     25.. 

2J..2 

27.4. 

24.1 

"      4 

22  I 

26  o 

*/•> 

22  6 

"     26  

21.2 

24.7 

21-4. 

"    is 

2O  O 

23  8 

21  6 

"       27.. 

21.8 

24..  c 

20.  0 

"      16 

21.4 

24  4 

21  6 

«      28.. 

i8.c 

22.8 

20.8 

"      17 

21  4 

21  4 

226 

"       29.  - 

2O.  I 

23.7 

17.0 

"      18 

17  0 

2O  7 

2O  2 

"     so 

17.0 

21.  C 

2O.O 

"      10 

18  4 

2O  I 

2Q  I 

«       3!    

17-7 

21.7 

10  I 

"      20" 

17  O 

18  c 

18  o 

Nov.    i  

17.0 

19.1 

18.3 

"       21  

17.8 

10.3 

17.0 

"         2    . 

16.6 

2O  I 

17  3 

"       22 

17  C 

17  7 

1C  Q 

"       3  

15.8 

18.1 

17.7 

"       23.. 

>  r 

i6.c 

I7.O 

16.2 

"       4-- 

s 

16.1 

17.7 

IC.O 

"      24  . 

i6.c 

17.4 

16.2 

"       c  

16.1 

18.3 

I7.C 

"     25  . 

I4-.  0 

*/•* 

i6.c 

16.3 

«       6.. 

15.6 

I7.O 

ic.c 

"     26  

14.8 

•v.3 

18.4 

1C.  I 

7  

1C.  3 

18.1 

1C.  2 

"      27 

14..  I 

18.8 

* 

16.0 

8  

I4.O 

17.6 

17.3 

"      28 

14.6 

16  o 

2 
13.6 

0.  . 

14-3 

•/•*j 

17.6 

/• 

14.6 

"        20 

13.3 

IC.O 

14.4 

«     10  

14.  7 

'  s 
17.6 

IC.O 

"        30" 

14.  C 

1C  4 

IC.C 

<Gen.  Av  

20.1 

23.1 

10.8 

10.  1 

20  8 

IQ  6 

Maximum   . 

CC.O 

CC.O 

42.  0 

AC   O 

•JO  O 

4O  O 

Minimum 

12.0 

IC.O 

13  O 

II.O 

11  O 

12  O 

M.  V.   . 

C.i8 

C.3O 

3  82 

4  10 

•J    •?•? 

4  OO 

Keys 


Key  4 


Dec      I 

4O  2 

2C.Q 

24.O 

Dec.  21  

37.0 

33.7 

2Q.O 

"         2 

2O  I 

24  4 

20.2 

"       22    

3/-V 

26.2 

26.6 

22.2 

"       7 

17  7 

23  2 

2O.4 

"       23    . 

2O.Q 

23.4 

22.6 

«    i  

IQ  2 

21  4 

10.3 

"       24    

22.4 

21.4 

20  6 

«    t  

17  8 

***5 

23  6 

18.1 

"      2C 

10.4 

21.3 

^,y.«j 

10  8 

"      6" 

ICQ 

18  8 

16.0 

"      26 

21.2 

20.  3 

2O  4 

"         7 

16  1 

22  7 

176 

"     27 

10.4 

10  O 

iw.ij. 

18.0 

"       8 

14  6 

IQ  Q 

17  3 

"    28 

17  4 

i8.c 

17  I 

"          0 

ICQ 

18  6 

17  O 

"       20 

1C.  2 

j.u-3 

18  7 

i/.t 
17  6 

"     10 

16  i 

IQ  2 

163 

"      30 

1C  7 

IQ  2 

16  c 

"     ii 

***«j 

13  Q 

17  8 

IC.C 

"     31 

17  C 

17  7 

17  2 

"       12 

»J'V 

13  Q 

17  7 

HA 

,        J1  
Jan.     I 

'  ? 

ic  6 

1C  Q 

1C  3 

"     13 

13  O 

'/' 

16  7 

14  C 

2 

l^j.U 

JS  6 

IQ  7 

14  O 

«  11  

14  4 

166 

14  I 

"       3 

16  o 

iy./ 

16  Q 

1C  7 

"    1^ 

I3.O 

ic.  8 

IC-4 

"  4      ;  ; 

IC-4 

18.4 

1C-  1 

"     16 

12.8 

*3>w 
16.2 

7 
14.6 

"     s 

IC.O 

18.1 

14.3 

"      17  . 

12.4 

17.7 

IC.O 

"       6 

I4.C 

18.3 

17.1 

"     18  

13.  1 

•/•/ 

i6.c 

14.1 

"       7  

I4.I 

16.6 

13.2 

"     I9-. 

I3.O 

»»».3 

16.7 

13.4 

"       8  

12.7 

20.  c 

13.7 

«  20.:.... 

13.2 

1C.  I 

13.7 

"       9.  . 

13.2 

•~  3 

16.2 

1C.  3 

Gen.  Av  

l6.3 

10-2 

16.6 

18.3 

2O.2 

17.8 

Maximum  

C7.O 

3O.O 

29.0 

42.0 

42.O 

33.O 

Minimum  

II.O 

I3.O 

I2.O 

II.O 

I4.O 

I2.O 

M.  V  

3.36 

2.7O 

2.  1C 

4.06 

> 

2.61 

2.86 

AN  EXPERIMENT  IN  ASSOCIATION 


287 


Key -5 


Key  6 


Date 

A 

B 

C 

Date 

,4 

B 

C 

Jan     10 

1C   Q 

-3  1.7 

1Q  I 

Tan.   20 
Jan.    29. 

38.6 

36.3 

2 

"      II 

24..  Q 

23.  C 

21.1 

6       2 

28.0 

22.9 

"       12 

21.2 

22.  C 

•>  J 
21.6 

"     3i" 

23.2 

22.1 

v 

10.6 

"       13.. 

18.7 

2O.  Q 

18.4 

Feb.     i 

18.4 

18.5 

18.2 

"       U-. 

18.0 

19.  1 

20.  c, 

"         2    

16.8 

2O.4 

18.6 

"        1C.  . 

16.5 

18.4 

-^•5 
16.2 

"          3 

17.4 

19.8 

18.3 

«     16.. 

.V.J 

16.1 

2O.3 

17.7 

"       4  - 

16.6 

18.4 

I7.r 

1     17  

16.0 

17.7 

16.3 

"       I 

14.7 

16.6 

18.1 

'     18  

IC..9 

17.7 

*V.J 

16.4 

«  I.: 

14.7 

18.2 

16.0 

'     19.  . 

13-9 

I7.Q 

;.  T 
16.7 

7.. 

14.3 

17.0 

17.2 

'       20 

14..  0 

C.  " 

lo  o 

JC  Q 

"       8 

16  o 

10.  1 

ICQ 

'       21 

1C.  I 

JC.  7 

168 

"        9 

14  8 

16.0 

•3*** 

i?.  8 

'       22 

13.7 

17.2 

14.  O 

"     10  " 

*T-U 

14  8 

16.2 

JC.C 

'      23 

JC.  I 

16.0 

14.  1 

"       II 

14.0 

ic.q 

jc.3 

*       24. 

JC.  I 

16.0 

H.I 

"       12 

13-0 

14.8 

a3O 

13.8 

*       2C  .  . 

I4-.7 

ic.7 

14.7 

"       13 

13-3 

14..  7 

11.  C 

'       26.. 

Ii.  I 

16.2 

I4.Q 

"  4 

12.  C 

13.8 

13.8 

'       27  

I4.O 

14.8 

13.6 

"  il 

12.3 

14.0 

I^.O 

'       28  

I'?.'? 

1C.  7 

11.7 

"     16 

12.3 

13.8 

I4--4. 

'       2Q1.  . 

"     17- 

12.3 

XJ.W 

ic.6 

11.7 

Gen.  Av 

17.1 

186 

17  3 

l63 

18  6 

163 

Maximum  
Minimum  
M.  V. 

38.0 
II.O 

3.C2 

40.0 
13-0 
2.80 

35-o 

12.0 
2.80 

43-o 

II.O 

3  61 

40.0 

I2.O 

3.74 

25-0 
12.0 
2  ic 

Key  7 


Feb.  1  8 

•7C.3 

31  4 

27  4 

Mar  2 

146 

ic  4. 

ic  2 

"      10 

2C.C 

JA-4 
23  6 

22  I 

"       3 

14.  O 

1V4 

16  o 

14.  C 

20  . 

20.  0 

21.  1 

2O  O 

"     4 

13  8 

146 

14.  2 

"      21  

18.1 

17.  c 

18  c 

"     5 

13  3 

6 

13  2 

1      22  

19.  i 

*/o 
18.1 

17.  0 

«  1: 

13.2 

6 

1-2    2 

'      23.  . 

18.2 

19.3 

18.7 

"     7 

13.2 

Hi 

14.  O 

'      M 

18.1 

I8.C 

17.2 

"     8 

12.6 

14  2 

13  0 

«    25  

17.2 

I8.S 

18.4 

"     9  

13-3 

14.7 

12-9 

4   26  

16.8 

17.1 

17.2 

tf\   T 

'   27  

13.6 

16.8 

15.6 

174 

177 

10-7 

«     28  

13.8 

16.6 

16.0 

39-° 

Mar.   i  

15.4 

15.1 

14.6 

Mv 

7   ^0 

13.0 

•9  fin 

3-°9 

•52 

Some  of  these  curves  show  that  the  larger  part  of  improve- 
ment is  done  during  the  first  test.  Usually,  however,  there 
was  a  constant,  though  slow,  progress  in  improvement  until 
the  end  of  the  twenty  tests.  Practise  showed  its  influence 
to  the  end  of  the  series,  with  every  indication  that  the  averages 
could,  with  further  practise,  be  further  reduced. 

Secondary  factors,  such  as  fatigue,  concentration  of  atten- 
tion, indisposition,  distraction,  etc.,  all  had  great  influence 

1One  day  short  by  oversight. 

2  Periods  missed  on  account  of  sickness. 


288  c.  G.  BRADFORD 

on  the  work.  The  conscious  processes  were  very  susceptive 
to  these  influences. 

In  learning  the  associations  of  the  different  keys  mne- 
monics proved  helpful,  by  taking  notice  that  certain  associa- 
tion letters  formed  initials  of  familiar  names,  etc.,  while  some 
had  to  be  retained  by  sheer  force  of  memory. 

In  some  cases  the  peculiarity  in  sequence  of  the  letters 
or  pairs  of  letters  associated  caused  retardation  in  association 
processes. 

Regarding  the  theory  of  interference  upon  completing 
one  key  and  taking  up  a  different  one  the  writer  believes  that 
probably  there  is  a  certain  degree  of  interference;  he  also 
thinks  there  is  a  certain  amount  of  learning  in  the  former  key 
transferred  to  the  new  one,  and  that  there  is  a  resultant  of 
forces  present,  which,  in  general,  makes  possible  a  lower  time 
rate.  In  the  present  investigation  there  was  constant  lower- 
ing of  the  beginning  time  rate  as  progress  from  key  to  key 
was  made;  which,  it  would  seem,  shows  conclusively  that 
there  was  a"  transference  of  learning  from  one  key  to  another, 
and  that  the  evil  effects  of  interference  were  largely  neutral- 
ized. 


A  NOTE  ON  THE  EFFECT  OF  RHYTHM  ON  MEMORY 

BY  HENRY  FOSTER  ADAMS 

University  of  Michigan 

In  spite  of  the  poor  standing  of  the  "class"  experiment, 
the  writer  has  been  so  impressed  by  the  similarity  in  the 
results  of  three  such  tests,  that  he  thinks  the  data  obtained 
will  be  of  general  interest  to  students  of  memory  problems — 
the  more  so,  as  some  of  the  conclusions  are  in  direct  contra- 
diction to  the  results  obtained  in  certain  other  investigations. 

The  object  of  the  experiment  was  to  test  the  effect  of  some 
of  the  various  kinds  of  rhythm  upon  the  memory  for  numbers. 
The  rhythms  used  were  the  trochaic,  iambic,  dactylic, 
anapestic  and  amphibrachic  forms,  together  with  a  non- 
rhythmic  series.  The  investigation  was  carried  on  in  the 
time-honored  way.  The  material  consisted  of  9  and  10 
digits  arranged  haphazard,  for  example,  381427695.  Such 
a  group  was  read  at  a  rate  of  between  90  and  100  per  minute, 
Eight  such  groups  constituted  one  series.  One  9  digit  series 
and  one  10  digit  series  were  used  for  each  of  the  different 
kinds  of  rhythm. 

The  rate  of  90  to  100  per  minute  was  used  in  the  endeavor 
to  obviate  subjective  grouping  on  the  part  of  the  subjects, 
and  because  it  would  be  about  equally  advantageous  for  the 
two-part  and  three-part  rhythms.  According  to  Bolton's 
work  upon  rhythm,  it  was  found  that  75  per  minute  was  the 
most  favorable  rate  for  two-part  subjective  rhythms,  and  130 
per  minute  for  the  three-part  subjective  groupings.  The 
intermediate  rate  was  therefore  used,  for  this  experiment  con- 
cerned itself  with  objective  groupings  only.  The  subjects 
were  instructed  to  write  down  as  many  of  the  numbers  as 
they  could  remember  immediately  after  the  reading  of  one 
group.  They  were  told  to  be  sure  to  get  the  right  number  in 
the  right  place  and  to  put  dashes  for  the  forgotten  numbers, 

289 


290 


HENRY  FOSTER  ADAMS 


so  that  those  given  correctly  should  appear  in  the  correct 
place  in  the  combination. 

The  results  were  recorded  in  the  usual  way.  A  number 
correctly  given  and  in  the  right  place  in  the  combination  was 
awarded  a  credit  of  100  per  cent.  A  transposition  of  two 
numbers  was  given  half  credit,  or  50  per  cent.  What  might 
be  called  a  half  transposition,  or  a  number  which  was  shifted 
one  place  to  the  right  or  left  with  an  incorrect  number  appear- 
ing in  its  place,  was  given  a  value  of  25  per  cent.  The  results 
are  consequently  given  in  percentages  of  the  total  amount 
recalled. 

The  series  were  given  in  such  a  way  as  to  obviate  as  far 
as  possible  the  effects  of  practice  for  any  meter.  Frequent 
rests  were  given  the  subjects  so  that  fatigue  might  not  inter- 
fere with  the  results. 

A  total  of  180  subjects  was  used,  80  men  and  100  women, 
all  of  them  coming  from  the  class  in  introductory  psychology 
at  the  University  of  Michigan.  The  first  group,  consisting 
of  50  persons,  25  men  and  25  women,  performed  the  experi- 
ment during  the  winter  of  1911  and  1912.  During  the  winter 
of  1912  and  1913  about  80  persons  were  experimented  upon, 
and  the  papers  of  25  men  and  of  25  women  were  selected  at 
random.  During  the  winter  just  passed  (1913-1914)  30  men 
and  50  women  performed  the  same  experiment. 

Since  certain  differences  appear  in  the  masculine  and 
feminine  types  of  reaction,  it  will  be  well  to  treat  them  at 
first  separately  and  then  note  the  sex  differences.  The  fol- 
lowing table  shows  the  results  registered  by  the  men  in  the 
9  digit  series. 

TABLE  I 

MEN.    9  DIGITS 


Group 

N.  R. 

Troc. 

Iamb. 

Dact. 

Amph. 

Anap. 

Av. 

I 

2 

3 

74.1 
77.0 
71.0 

75-o 

73-2 

68.2 

78.9 
71.2 

72.0 

85.0 
88.5 
88.7 

80.4 
837 

89.7 
83.5 

88.8 

80.5 
78.9 
78.7 

Average  .1      73.7 

71.8 

74.0 

87.5 

82.1 

87.3 

794 

N.  R.  indicates  that  the  numbers  were  read  without  accent, 


EFFECT  OF  RHYTHM  ON  MEMORY  291 

or  rather  with  the  amount  of  accent  as  nearly  uniform  as 
possible.  The  other  headings  show  the  rhythm  used — 
trochaic,  iambic,  dactylic,  amphibrachic  and  anapestic. 

Until  the  results  of  the  third  set  of  papers  had  been 
obtained,  there  was  no  intention  of  using  them  for  anything 
but  purposes  of  illustration  in  class.  The  records  of  two  sets 
had  therefore  been  destroyed  before  any  individual  char- 
acteristics had  been  worked  out.  Realizing  that  the  averages 
as  shown  in  the  tables  may  be  greatly  affected  by  some 
extreme  cases  rather  than  representative  of  a  general  tend- 
ency, the  writer  regrets  this  loss.  However,  he  has  worked 
out  the  last  set  of  papers  not  only  in  percentage  values,  but 
also  in  terms  of  position  by  The  Order  of  Merit  Method, 
where  the  effect  of  extreme  cases  is  eliminated.  There  were 
no  substantial  differences  in  the  results  obtained  by  these 
two  methods,  certainly  no  differences  of  kind.  There  were 
a  few  differences  of  degree. 

A  study  of  the  table  brings  out  these  facts : 

I.  There  is  a  variation  of  6  per  cent,  in  the  recall  of  the 
unaccented  series  amounting  to  0.54  of  one  syllable  when  we 
compare  the  best  group  with  the  worst.  There  is  no  correla- 
tion between  the  ability  to  recall  the  non-rhythmic  series 
and  especial  ability  to  recall  any  particular  kind  of  metrical 
presentation.  The  one  thing  which  does  appear  is  that  the 
group  which  had  the  highest  recall  value  for  the  unaccented 
series  had  the  lowest  for  the  average  of  the  three-part  meters. 
This  same  relation  will  not  hold  for  the  other  two  groups, 
however,  for  the  group  which  was  the  worst  in  the  non- 
rhythmic  series  was  not  the  best  in  the  three-part  rhythms, 
unless  we  omit  the  amphibrach.  If  we  do  omit  the  amphi- 
brach entirely,  we  do  find  the  reverse  correlation,  that  the 
poorest  group  in  the  non-rhythmic  series  was  the  best  in 
the  three-part  rhythms  considered  as  a  whole,  while  the  best 
non-rhythmic  group  was  the  worst  in  the  three-part  rhythms. 

Another  interesting  result  which  appears  from  a  study  of 
the  table  is  that  the  group  of  men  which  did  best  in  the  non- 
rhythmic  series  did  better  on  the  falling  rhythms,  the  trochaic 
and  dactylic,  than  they  did  on  the  rising  meters,  the  iambic 


292  HENRY  FOSTER  ADAMS 

and  anapestic;  while  those  who  were  the  worst  in  the  un- 
accented series  recalled  the  rising  meters  better  than  the 
falling. 

2.  In  two  out  of  three  groups  and  in  the  average  of  the 
three  groups,  the  trochaic  form  of  rhythm  has  not  as  high  a 
memory  value  as  the  non-rhythmic  series. 

3.  In  two  out  of  the  three  cases  and  in  the  average,  the 
iambic  form  of  rhythm  is  better  for  the  purposes  of  recall 
than  the  non-rhythmic  series.     We  are  justified  in  stating, 
then,  that  the  iambic  form  of  presentation  is  very  slightly 
better  than  that  without  rhythm.     Considering  the  average 
for  the  two-part  rhythms,  we  find  it  to  be  slightly  worse  than 
the  unaccented  series. 

But  it  must  be  remembered  that  the  series  of  9  digits  read 
in  two-part  rhythm  is  scarcely  a  fair  test,  for  one  number  is 
left  over,  making  an  incomplete  foot  at  the  end  of  the  line. 
When  this  incomplete  foot  is  unaccented,  as  in  the  iambic 
form,  the  group  has  a  higher  memory  value,  in  two  cases  out 
of  three,  than  when  the  incomplete  foot  is  accented.  It  is 
interesting  in  this  connection  to  call  attention  to  the  fact 
brought  out  by  Miss  Rowland  in  connection  with  visual 
rhythms,  namely,  that  a  change  in  the  minor  element  of  the 
series  is  more  disturbing  than  a  change  in  the  major  element. 

4.  The  three-part  rhythms  are  all  better  than  the  un- 
accented series.     The  dactylic  and  anapestic  forms  are  about 
equal,  with  the  dactylic  very  slightly  in  the  lead  and  the 
amphibrachic  is  the  worst,  but  better  than  the  two-part  and 
non-rhythmic  series.     It  is  entirely  natural  that  the  three- 
part  rhythms  should  be  the  best  in  this  part  of  the  experi- 
ment, for  most  of  us  have  been  trained  from  our  earliest 
days  in  the  grade  schools  to  group  numbers  by  hundreds, 
thousands,  millions,  etc. 

The  following  table  shows  the  results  registered  by  the 
women  in  the  9  digit  series. 

The  study  of  this  table  shows  the  following  facts : 
I.  There  is  a  variation  of  3.7  per  cent,  in  the  recall  of  the 
unaccented  series  amounting  to  0.33  per  cent,  of  one  syllable 
when  we  compare  the  best  group  with  the  worst.     Here  we 


EFFECT  OF  RHYTHM  ON  MEMORY 
TABLE  IA 


293 


Group 

N.  R. 

Troc. 

Iamb. 

Dact. 

Amph. 

Anap. 

Av. 

I 
2 

3 

76.5 

76.0 
72.8 

72.6 

7M 
6S.S 

78.1 
70.7 
70.0 

91.8 

944 
90.8 

88.1 
83.7 

99.1 
95-3 
90-3 

83.6 
82.6 
78-7 

Average  . 

74-5 

68.1 

72.2 

92.0 

85.0 

93-7 

80.9 

find  that  the  best  non-rhythmic  group  is  also  the  best  in  the 
two-part  and  three-part  rhythm  series,  while  the  worst  non- 
rhythmic  group  is  also  the  worst  for  all  forms  of  rhythmic 
presentation.  The  best  non-rhythmic  group  is  best  in  the 
falling  rhythms,  while  the  worst  non-rhythmic  group  is  best 
in  the  rising  two-part  and  the  falling  three-part  rhythms. 

2.  In  all  three  tests,  the  trochaic  form  is  not  as  good  as 
the  non-rhythmic. 

3.  The  iambic  form  is  in  general  below  the  non-rhythmic, 
but  is  better  than  the  trochaic.     Again,  as  with  the  men,  the 
series   having   the   extra   unaccented   syllable   has    a    higher 
memory  value  than  the  series  containing  the  extra  accented 
syllable. 

4.  The  three-part  rhythms  are  considerably  better  than 
either  the  unaccented  series  or  the  two-part  meters.      The 
anapestic  form  is  best,  the  dactylic  next  and  the  amphibrachic 
worst. 

Averaging  the  results  of  the  men  and  women  in  the  9  digit 
series,  we  find  that  the  three-part  rhythm  is  best,  the  non- 
rhythmic  next  and  the  two-part  rhythm  the  worst  of  all. 
There  is  also  a  tendency  for  the  rising  meters  to  have  a  greater 
memory  value  than  the  falling  ones. 

Considering  now  the  differences  between  the  masculine 
and  feminine  types  of  reaction,  we  find: 

1.  The  total  amount  recalled  by  women  is  greater  than 
that  recalled  by  men,  80.9  to  79.4  or  100  to  98.1. 

2.  In  the  non-rhythmic  series,  the  women  recalled  more 
than  the  men  absolutely,  but  relatively  less.     For  when  we 
consider  that  the  women  remembered  actually  more  than 
the  men  did  taking  the  series  as  a  whole,  the  percentage  of 
the  series  recalled  in  the  non-rhythmic  series  is  less  for  the 


294 


HENRY  FOSTER  ADAMS 


women  by  a  ratio  of  92.1  to  93.0.  The  non-rhythmic  form 
of  presentation,  then,  is  relatively  worse  for  the  women  than 
it  is  for  the  men  in  spite  of  the  fact  that  they  recalled  more 
actually. 

3.  The   two-part   rhythm   is    better    for    the   men,   both 
absolutely   and    relatively,   than   it   is   for   the   women,   the 
absolute  ratio  being  72.9  for  the  men  to  70.1  for  the  women, 
and  relatively  92.0  to  86.8. 

4.  The  three-part  rhythm  is  better  for  the  women,  both 
absolutely  and  relatively,  by  the  ratio  of  90.2  to  85.6  abso- 
lutely, or  112  to  108  relatively. 

5.  With  the  men,  the  dactylic  form  of  meter  had  a  some- 
what   higher    memory    value,    while    with    the    women    the 
anapestic  form  was  best. 

Turning  now  to  the  consideration  of  the  10  digit  series, 
which  was  given  to  but  two  sets  of  persons,  we  find  a  relative 
rise  in  the  memory  value  of  the  two-part  rhythms,  and  a 
relative  decrease  in  the  three-part,  showing  that  the  ir- 
regularity of  the  last  foot  was  a  determining  factor.  The 
total  amount  remembered  in  this  series  was  considerably 
less  than  in  the  9  digit  series,  as  might  naturally  be  expected. 
Table  II.  shows  the  results  of  the  men  in  the  10  digit  series. 

TABLE  II 


Group 

N.  R. 

Troc. 

Iamb. 

Dact. 

Amph. 

Anap. 

Av. 

2 

3 

71.0 
62.3 

697 
634 

72.7 
69.0 

77.1 
75-5 

71.2 

76.9 

73-o 

73.6 
69.1 

Average  . 

644 

644 

70.8 

76.6 

71.2 

74-8 

704 

This  table  shows: 

1.  The  recall  of  the  unaccented  series  shows  a  variation  of 
almost  one  syllable  when  we  consider  the  results  of  the  two 
groups.     The  best  group  in  this  series  was  absolutely  the 
best  in  the  three-part  rhythms,  but  relatively  worse  than  the 
other  group.     There  is  no  evident  correlation  between  the 
recall  of  the  unaccented  series  and  either  the  falling  or  rising 
rhythms. 

2.  The   trochaic   rhythm   is   equal   to   the   non-rhythmic 


EFFECT  OF  RHYTHM  ON  MEMORY 


295 


series.  This  is  true  of  the  average,  the  two  series  differing 
somewhat.  In  one,  the  trochaic  is  better  and  in  the  other 
worse  than  the  unaccented  series. 

3.  The  iambic  series  is  better  in  both  cases  than  the  non- 
rhythmic.     On  the  average,  then,  the  two-part  rhythm  with 
series  of  10  digits  is  better  than  the  unaccented  series. 

4.  All    of    the    three-part  are  better  than  the  two-part 
kinds  of  rhythm,  the  dactylic  holding  the  highest  place,  the 
anapestic  second  and  the  amphibrachic  coming  last,  as  was 
the  case  in  the  9  digit  series. 

The  following  table  gives  the  results  of  the  women  in  the 
10  digit  series: 

TABLE  II A 


Group 

N.  R. 

Troc. 

Iamb. 

Dact. 

Amph. 

Anap. 

AY. 

2 

3 

63.5 

61.0 

68.5 
64.1 

69.8 
654 

72.9 
70.4 

68.S 

74-3 

72.2 

69.8 
66.9 

Average  . 

62.0 

65.5 

67.0 

71.2 

68.5 

73-o 

67.9 

A  consideration   of  this   table  brings   out  the  following 
points : 

1.  There  is  very  little  variation  between  the  two  groups 
of  women  in  the  recall  of  unaccented  material,  only  a  quarter 
of  one  syllable.     The  group  which  was  absolutely  worst  in 
the  recall  of  the  non-rhythmic  series  was  relatively  better 
in  the  recall  of  the  three-part  rhythms. 

2.  In  both  series,  both  forms  of  the  two-part  rhythm  are 
better  than  the  unaccented  series.     The  iambic  form  is  better 
than  the  trochaic. 

3.  Each  of  the  three  forms  of  three-part  rhythm  is  better 
than  either  of  the  two-part  meters.     But  with  the  women, 
the  anapestic  form  of  meter  is  better  than  the  dactylic.     The 
amphibrachic  is  lowest  of  all. 

Taking  into  account  the  sex  differences,  we  find  that: 

I.  The  total  amount  recalled  by  the  men  is  greater  than 

that  recalled  by  the  women,  70.4  to  67.9  or   100  to  96.5. 

Considered    absolutely,    the    women    recall    less    in    all    the 

different  forms  of  rhythm.     This  is  true  of  the  average  of  the 


296 


HENRY  FOSTER  ADAMS 


non-rhythmic,  two-part  and  three-part  rhythms.  The  women 
did  recall  slightly  more  in  the  trochaic  form.  Considered 
relatively,  we  find  the  men  to  be  better  in  the  non-rhythmic 
series,  worse  in  the  two-part  meters,  and  slightly  better  in 
the  three-part  rhythms,  when  we  consider  all  the  three-part 
meters  together. 

2.  The  men  are  best  in  the  dactylic  meter  and  the  women 
in  the  anapestic. 

The  task  would  be  incomplete  if  no  endeavor  were  made 
to  bring  together  the  results  of  the  9  digit  and  the  10  digit 
series.  It  would,  of  course,  be  unfair  to  average  them,  but 
it  is  possible  to  take  the  average  recall  for  each  group  and 
reduce  the  amount  recalled  for  each  kind  of  meter  to  a 
percentage  of  this  average.  This  would  do  no  injustice  to 
any  group  considered  alone  and  would  make  comparisons 
possible.  Combining  the  previous  tables  for  the  men,  and 
omitting  the  amphibrachic  form  of  meter — for  it  shows 
nothing  striking — we  obtain  this  table: 

TABLE  III 


Group 

N.  R. 

Troc. 

Iamb. 

Dact. 

Anap. 

9  digits  .  . 

I 

92.2 

97.  -z 

98.0 

IOC.9 

III.7 

10  digits  

2 

3 

2 

97-4 
90.2 
96.7 

•yj  j 

93-6 
86.6 
94-8 

90.1 

91.5 
99.0 

1  12.0 
II2.8 
IOC.O 

105.8 
II3.O 

10^.2 

3 

90.1 

91.7 

99-8 

109.2 

105.2 

Av.  of  9  digits  
Av.  of  10  digits.  .  .  . 

92.8 
9i.S 

91.0 
91-5 

93-3 
100.6 

IIO.2 
IO9.O 

IIO.O 
106.3 

Difference  

I.I 

o.c 

7.7 

1.2 

•5.7 

The  main  value  of  this  table  seems  to  be  to  show  the 
amount  of  damage  done  by  introducing  irregularity  into  the 
series.  There  is  a  difference  of  1.3  in  the  non-rhythmic 
series  in  favor  of  the  shorter  groups.  The  two-part  rhythms 
are  better  in  the  10  digit  series  by  an  average  of  3.9  and  the 
three-part  rhythms  are  better  in  the  9  digit  series  by  an 
average  of  2.45.  On  the  average,  the  three-part  rhythms 
seem  to  be  affected  less  by  the  introduction  of  an  irregularity 
than  do  the  two-part,  3.9  to  2.45.  Moreover  the  falling 


EFFECT  OF  RHYTHM  ON  MEMORY 


297 


rhythms  are  less  affected  by  the  extra  measure  than  are  the 
rising  meters,  0.85  to  5.5. 

TABLE  \\\A 

WOMEN 


Group 

N,  R. 

Troc. 

Iamb. 

Dact. 

Anap. 

0  digits 

I 

qi.c 

86.8 

03  .c 

IOQ.Q 

118.8 

IO  digits  

2 

3 

2 

92.3 
92.5 
Ql.O 

86.6 
83.2 
08.  i 

86.0 
88.9 

IOO.O 

1147 
II5-2 

I  O-i.-i 

"5-9 
114.6 
106.4. 

3 

91.2 

95-8 

98.0 

I05.I 

108.0 

Av.  of  9  digits  
Av.  of  10  digits  .... 

92.2 
91.4 

83.3 
96.5 

89.4 
99.0 

II3.8 
105.0 

116.0 
107.6 

Difference  

0.8 

13-2 

9.6 

8.8 

8.4 

This  table  shows  that  there  is  a  slight  relative  difference 
— 0.8 — in  the  recall  of  the  non-rhythmic  series,  the  difference 
being  in  favor  of  the  shorter  series.  The  two-part  rhythms 
are  better  in  the  10  digit  series  by  an  average  of  11.4  and  the 
three-part  rhythms  are  better  in  the  9  digit  series  by  an 
average  of  8.6.  The  two-part  rhythm,  then,  is  affected  a 
little  more  by  the  introduction  of  irregularity  than  is  the 
three-part  rhythm.  In  both  the  two-part  and  the  three-part 
rhythms,  the  falling  meter  is  the  more  affected,  n  to  9. 
There  is  less  disturbance  of  the  three-part  rhythms  than  of 
the  two.  The  other  points  which  are  brought  out  by  this 
table  have  been  considered  before,  so  may  be  omitted  here. 

When  we  consider  the  sex  differences  as  brought  out  by 
a  comparison  of  the  results  of  the  9  digit  and  the  10  digit 
series,  we  find  that: 

1.  The  feminine  recall  is  better  for  the  9  digit  series  by  a 
ratio  of  80.9  to  79.4  or  100  to  98.1,  whereas  in  the  longer 
series  the  masculine  recall  is  better  by  a  ratio  of  70.4  to  67.9 
or  100  to  96.5.     Considering  the  whole  experiment,  then,  the 
men  have  slightly  better  memories  for  numbers  than  the 
women,  the  ratio  being  100  to  99.1.     This  difference  is  very 
slight  and  might  be  called  negligible. 

2.  The  irregularities  introduced  into  the  series  are  more 
disturbing  to  the  women  than  to  the  men,  8.16  to  2.8. 


298  HENRY  FOSTER  ADAMS 

3.  The  irregularity  on  the  average  affects  the  three  part 
rhythms  less  than  it  does  the  two-part  for  both  sexes. 

4.  With  the  men,  the  dactylic  form  of  meter  is  the  best  in 
all  cases;  with  women,  the  anapestic. 

5.  The  irregularity  affects  the  rising  meters  more  than  it 
does  the  falling  in  the  case  of  the  men;  whereas  the  falling 
meters  are  more  affected  in  the  case  of  the  women. 

Since,  as  has  been  seen,  the  9  digit  series  introduces  a 
disturbing  factor  into  the  two-part  rhythms  and  the  10  digit 
series  into  the  three-part  rhythms,  it  will  be  interesting  to 
consider  the  two-part  rhythm  10  digit  series  together  with 
the  three-part  rhythm  9  digit  series.  The  results  obtained 
from  this  consideration  differ  from  the  rest  of  the  results 
only  in  this  particular,  that,  with  one  exception,  any  rhythm 
is  better  than  no  rhythm  at  all.  This  exception  occurs  in 
the  case  of  the  men  and  with  trochaic  rhythm,  it  being  exactly 
equal  to  the  non-rhythmic  series. 

This  way  of  regarding  the  results  also  raises  the  feminine 
recall  somewhat  above  the  masculine,  but  shows  that  it  is  a 
more  precarious  thing,  very  easily  disturbed. 


DIAGNOSTIC   VALUES    OF    SOME    PERFORMANCE 

TESTS1 

BY  THOMAS  H.  HAINES,  M.D.,  PH.D. 

Bureau  of  Juvenile  Research,  Columbus,  Ohio 

In  preliminary  mental  examinations  of  a  number  of  recent 
admissions  to  the  Ohio  Girls'  Industrial  School,  the  results 
obtained  from  the  Binet  and  Point  Scale  ratings  of  intelli- 
gence, set  apart  three  groups,  which  it  seemed  desirable  to 
investigate  further.  These  groups  follow: 

1.  Twenty-one  high-grade  morons,  whose  Binet  ratings 
average  II  years,  with  a  mean  variation  of  3  years,  and  whose 
Point   Scale   ratings,   transformed   into   years,   average    n.6 
years,  with  a  mean  variation  of  .4  year. 

2.  Sixteen,  concerning  whose  intelligence  defects  we  are 
in  doubt,  because  of  the  disparity  between  the  Binet  and 
Point  Scale  findings.     Binet  ratings  of  these  sixteen  average 
1 1. 6  years,  with  a  mean  variation  of  .2  year.     By  Point  Scale 
rating,  these  are  all  12  years  or  more.     One  only  is  flat  12. 
Four  are  over  15  years. 

3.  Twenty-six,   who   show   no   defect   in   intelligence   by 
either  of  these  ratings,  being  twelve  years  or  more  by  both 
scales.     Fifteen  of  them  get  credits  for  more  than  the  82 
points  for  fifteen  years. 

The  actual  ages  of  these  sixty-three  girls,  reckoned  by 
the  nearest  birthdays  at  the  times  of  examination,  range  from 
12  to  1 8  years.  The  median  ages  for  each  subgroup,  in  the 
same  order  as  above,  are  15.8  years,  16.5  years,  and  16.5  years. 
The  average  ages  for  each  subgroup,  in  the  same  order,  are 
15.2  years,  16  years,  and  15.9  years.  The  median  age  of 
the  sixty-three  girls  is  16.35  years,  and  the  average  age  of 
the  sixty-three  is  15.7  years. 

For  the  further  study  of  these  cases,  recourse  was  had 

1  Read  before  Section  L  of  the  American  Association  for  the  Advancement  of 
Science,  December  31,  1914. 

299 


300  THOMAS  H.  HA1NES 

to  the  following  tests.  We  lack  standards  in  all  these  tests. 
For  the  more  delicate  diagnosis  of  intelligence  and  other 
mental  defects  in  persons  of  mentalities  of  more  than  ten 
years,  there  is  no  method  of  procedure  in  any  wise  comparable 
for  accuracy  of  measurement  to  the  Binet  and  Point  Scale 
for  the  earlier  stages  of  development.  These  performances 
and  other  tests  have  been  used  widely  as  supplementary  aids 
to  psychologists'  native  intuitions.  Methods  of  testing  have 
been  developed,  but  no  standards  of  the  meaning  of  results. 
These  subjects  having  been  rated  by  the  two  scales  (Binet 
and  Point),  and  classified  with  respect  to  the  1 2-year  line, 
we  have  a  means  of  preliminary  evaluation  of  these  supple- 
mentary tests.  We  may  ascertain  which  do  and  which  do 
not  correlate  with  the  scales.  It  is  not  standardization. 
It  is  merely  evaluation.  Standardization  is  not  possible 
with  defectives. 

LIST  OF  THE  SUPPLEMENTARY  TESTS 

1.  Picture  Form  Board   (farm  scene,  mare,  colt,  chicken, 

sheep.     Two  right-angled  triangular  pieces  to  fit  into 
an  isosceles  triangle).     (Healy.) 

2.  Construction  Puzzle  (A).     (Healy.) 

3.  Construction  Puzzle  (B).     (Fernald.) 

4.  Labyrinth  (B).     (Boston  Psychopathic  Hospital.) 

5.  Visual  Verbal  Memory  Test.     (Schmidt.) 

6.  Auditory  Verbal  Memory  Test.     (Thorndike.) 

7.  Learning  Test.     (10  symbols  for  10  figures;  4  lines.) 

8.  Cross  Line  Test  (B).     (Healy.) 

9.  Motor  Coordination.     (Whipple.) 

10.  Opposites.     (Lists  I.  and  II.  of  Woodworth  and  Wells.) 

11.  Completion  Test.     (Boston  Psychopathic  Hospital.) 

12.  Moral  Discrimination  Test.     (Boston  Psychopathic  Hos- 

pital.)    (For  girls.) 

Table  I.  presents,  for  comparison,  the  summaries  of 
results,  from  each  of  the  three  groups  of  girls  for  each  of  the 
first  eleven  tests. 

The  first  four  tests  were  given  with  simple  directions,  and 
the  time  in  seconds  and  the  moves  or  errors,  recorded.  These 
are  averaged  for  each  of  the  three  groups. 


PERFORMANCE  TESTS 


301 


E  c 


*    4 


•5-S 
.2.S 


^  « 


^3  S2      *^> 


•0.3-,          fc     ^$5     *«      ££3      M 

fe  nH  *>         00         oS^'5  w 

QK«^  *J^_,  .        .2  »  J!    ?^Ji 

^S^eJ^cJ^WdJtjWt^OwalJ 

£  t  §  c^  S.>:  S  ^^  W^  o  g  B.8  g-o 

K  .  .1  5  9l        tl^rSrtlSrtbSiS*3.,   C 

*J*S^iJll^i^^*lS8l 

»^    H-i     i^    <-M     /*»     ^  **^     <»i<i\/*tH^K.     S^.     «^-«     K     « 


PQ      M 


2  S  £ 

o  >  > 

t  %  % 

5  S  S 

q\  vq  HH 

06  vd  &> 


32  ovo  o  o 


.a  •>  v      CD 

O^vo     ^         to 

HH  O*  tO 


: s  I  °$ 


^      « 
2     5 


2     ^ 


O      HH 
tO    O 


s    a 

ON       VO 


10  l^       00    N    T}-   i     O    rj- 
toOO         10  10  HH    |     to  o» 


$  ^ 

PQ  ~ 

a  S 

S  PH 

fe  jj 


»      >^          ^r^'2      "    2     ^ 

c32 


b>.00   ON  O         HH 


302  THOMAS  H.  RAINES 

In  the  Visual  Verbal  Memory  test,  a  sheet  was  handed 
the  subject  on  which  the  story  of  a  fire  was  printed,  one  line 
to  each  detail,  and  she  was  directed  to  read  it  once  aloud,  and 
to  do  it  carefully  so  she  could  remember  as  much  as  possible. 

In  the  Auditory  Verbal  Memory  test,  the  shipwreck  story 
was  read  to  her  four  times.  Times  for  recall  and  numbers 
of  details  are  averaged  for  each  of  the  Memory  Tests. 

In  the  Learning  test,  times  required  to  fill  three  lines,  and 
to  learn,  to  the  subject's  satisfaction,  were  recorded  and 
averaged,  as  well  as  the  numbers  of  errors  in  filling  the  4th 
line  from  memory,  and  the  times  for  the  memory  work. 

In  Cross  Line  (B)  test,  the  double  cross  was  drawn  on  a 
piece  of  paper  and  the  arabic  numerals,  1—9,  written  in  the 
nine  spaces.  The  explanation  of  how  the  symbols  could 
stand  for  the  numbers  was  accompanied  by  a  drawing  of 
each  symbol  as  the  number  was  named,  and  an  illustration 
given  of  writing  a  symbol  under  a  number.  The  subject  was 
asked  to  note  carefully  the  arrangement.  The  paper  was 
then  turned  over  and  six  numbers  written  in  a  line,  and  the 
subject  asked  to  make  the  corresponding  symbol  under  each. 

In  Motor  Coordination,  we  average  numbers  of  dots  made 
in  30  seconds,  and  the  errors,  i.  e.,  dots  on  lines  or  outside  of 
squares  intended,  or  a  second  dot  in  a  given  square. 

In  Opposites,  we  average  the  time  and  errors  (wrong 
words  and  omissions)  for  40  words.  The  observer  wrote  the 
opposites  and  was  not  hurried. 

In  the  Completion  test,  the  same  method  and  data  were 
used. 

From  an  inspection  of  the  table  it  is  at  once  evident  that 
some  of  these  tests  give  significantly  different  averages  in 
each  of  the  three  groups;  others  reveal  more  or  less  clear 
differences  as  between  the  not  defective  (mentality  of  12  years 
or  more),  and  the  doubtfully  defective.  Others  show  dif- 
ferences between  the  doubtfully  and  the  definitely  defective. 
Others  still  show  no  sufficient  differences  between  averages 
of  any  two  groups  to  make  them  of  any  diagnostic  value  in 
this  part  of  the  developmental  period. 

I.  In  the  first  class  of  tests,  are  (a)   the  Picture  Form 


PERFORMANCE  TESTS  303 

Board,  (b)  Construction  Puzzle  (A\  and  (c)  Opposites.  In 
the  Picture  Form  Board  averages,  there  appear  significant 
differences  in  the  increasing  time  throughout,  and  increased 
errors  in  the  defective.  Construction  Puzzle  A  gives  marked 
differences  in  both  time  and  moves.  It  seems  a  valuable 
means  of  differentiation  in  this  region.  Opposites  by  number 
of  errors  gives  significant  differences.  Defectives  are  set  off 
strikingly  both  by  time  and  numbers  of  errors. 

2.  In  the  second  class,  the  Labyrinth  averages  indicate 
some  diagnostic  value  in  differentiating  between  the  "non- 
defectives"  and  the  "Doubtfuls,"  both  in  time  and  number 
of  errors.     Both  the  verbal  memory  tests  on  the  other  hand 
seem   to   differentiate   between   the   "high-grade   defective" 
and  the  "doubtful"   in  the   number  of  details   recollected. 
The  norms  seem  to  be  ten  visual,  and  nine  auditory  details 
for  the  defective,  and  twelve  visual  and  nearly  ten  auditory 
details  for  the  doubtful.     The  Cross  Line  test  again  separates 
the  normals  and  doubtfuls  strikingly.     The  Completion  test 
is  much  less  valuable.     It  separates  non-defective  from  doubt- 
fuls by  time,  and  doubtfuls  from  defectives  by  numbers  of 
errors.     The  latter  difference  has  most  weight. 

3.  In  the  third  class,  Construction  Puzzle  (£),  the  Learn- 
ing test,  and  Motor  Coordination  seem  to  be  of  no  service 
for  differential  diagnosis  in  this  part  of  the  development  of 
mentality  from  ten  and  one  half  years  to  fifteen. 

We  compare  the  median  place  of  location  of  each  one  of  the 
ten  acts,  in  the  Moral  Discrimination  test,  for  each  of  the 
three  groups,  and  also  for  a  group  of  fourteen  first-year 
high-school  girls  of  ages  from  14  years  to  16.5  years,  with 
results  as  in  Table  II.1  The  figures  give  the  median  positions 
assigned  each  act  by  each  of  the  four  groups. 

"Flirting  with  a  nice  young  man"  is  deemed  much  worse 
by  the  normal  girls  than  by  any  of  the  delinquents.  Of  the 
delinquents,  the  high-grade  defectives  consider  it  worse  than 
the  other  subgroups. 

"Taking  a  hair  ribbon,"  is  rated  about  six  by  all,  i.  e., 

1  For  the  data  from  the  reactions  of  fourteen  high-school  girls,  I  am  indebted  to 
Dr.  R.  Pintner,  of  Ohio  State  University. 


3°4 


THOMAS  H.  HAINES 
TABLE  II. 


Normal 

Delinquent 

is^Yr. 
H.S. 

26 

Not 
Defec. 

16 
Doubt. 
Intell. 
Defect. 

21 

High- 
grade 
Defec- 
tives 

To  flirt  with  a  nice  young  man  on  the  street  

5-5 

57 
3-5 
5-5 
4-5 

8.5 

9-3 
2.4 

i-S 

9.1 

8-5 

5.8 
2.7 
5-3 

o.i 

8.6 
8.1 
1.9 

4-5 

7-5 

8.S 
6.2 

1.8 
5-3 
57 

8.2 

8.7 
2.4 

7-5 
74 

7.2 

5-9 
2-5 

57 
57 

7-5 
7-3 
1.9 

7-5 
7-5 

To  take  a  hair  ribbon  from  your  employer  when  she 
knows  nothing  of  it  ... 

To  spend  the  night  in  a  hotel  with  some  young  man.  .    . 

To  take  a  box  of  candy  from  the  store  where  you  work.  .  . 
To  tell  a  wicked  lie  about  some  girl 

To  get  mad  and  break  the  dishes  when  the  woman  for 
whom  you  work  finds  fault  with  you 

To  spank  the  baby  because  you  are  out  of  patience  

To  put  poison  in  the  food  of  some  one  whom  you  dislike  . 
Not  to  go  to  Sunday  school  and  church,  and  never  to 
read  your  bible  

To  throw  scalding  water  on  the  cat  

better  than  the  middle.  "Spending  the  night  with  a  young 
man  in  a  hotel"  is  rated  a  better  thing  to  do  by  the  normals 
than  by  any  of  the  delinquents.  Perhaps  this  is  due  to 
failure  to  understand  what  is  meant.  Of  the  delinquents, 
those  of  doubtful  intelligence  defect  place  it  nearest  the  worst 
thing  to  do. 

"Taking  a  box  of  candy"  is  placed  about  5.5  by  all  groups. 
"Telling  a  wicked  lie  about  a  girl"  is  much  worse  with  the 
normal  girls  than  the  delinquents.  The  delinquents  all  place 
it  about  the  same,  but  those  without  intelligence  defect 
consider  it  least  bad.  "Breaking  the  dishes  when  scolded" 
is  worse  for  the  high-grade  defectives  than  any  other  group. 
" Spanking  the  baby  when  out  of  patience"  is  least  bad  for 
the  normal  girls,  and  judged  worse  by  the  high-grade  defec- 
tives than  by  the  other  delinquents.  "Putting  poison  in  the 
food  of  one  you  dislike"  is  rated  about  the  same  by  all,  but 
some  worse  by  the  high-grade  defectives  and  those  of  no 
intelligence  defect. 

"Not  going  to  Sunday  school  and  church"  is  the  worst  of 
the  ten  offences  according  to  the  normal  girls.  It  is  moder- 
ately bad  for  the  delinquents  with  no  intelligence  defects, 
and  moderately  good  for  the  doubtfuls  and  defectives. 
"Throwing  scalding  water  on  the  cat"  is  the  second  best 


PERFORMANCE  TESTS  305 

act  with  the  normal  girls,  and  is  moderately  good  for  all  the 
delinquents. 

There  are  no  significant  differences  between  the  groups  of 
delinquents  in  regard  to  their  moral  judgments.  This  test  is 
of  no  value  for  differential  diagnosis  as  between  these  groups. 
The  startling  moral  judgments  of  the  normal  girls  suggest 
the  need  of  psychological  inquiries  into  ethical  foundations 
in  the  minds  of  girls. 

By  our  findings  then,  the  values  of  the  tests  for  differential 
diagnosis  of  our  three  groups  are  as  follows: 

1.  Tests  of  Value  for  Both  Distinctions 

The  Picture  Form  Board. 
Construction  Puzzle  (A). 
The  Opposites. 

2.  Tests  Good  for  Differentiation  of  the  Not  Defective  from  the 

Doubtful 

The  Labyrinth  (B). 
The  Cross  Line  (B). 

3.  Tests    Differentiating   the    High-grade    Defective   from    the 

Doubtful 

Visual  Verbal  Memory. 
Auditory  Verbal  Memory. 

4.  Tests  of  Doubtful  Diagnostic  Value 

Completion. 

5.  Tests  Showing  No  Definite  Diagnostic  Value 

Construction  Puzzle  (B). 

Learning. 

Motor  Coordination. 

Moral  Discrimination. 


PROCESSES  REFERRED  TO  THE  ALIMENTARY 

AND  URINARY  TRACTS:  A  QUALITATIVE 

ANALYSIS1 

BY  E.  G.  BORING 

Cornell  University 

Recently  the  writer  promised  a  descriptive  study  of  certain 
complex  organic  processes  that  have  their  origin  in  the  ali- 
mentary canal  and  the  uro-genital  system.2  The  present 
paper,  which  fulfills  that  promise,  presents  introspective 
descriptions  of  thirst,  hunger,  nausea,  the  call  to  defecation, 
defecation,  the  call  to  urination,  and  urination.  Descriptive 
accounts  were  obtained,  a  few  in  the  series  of  the  earlier 
experiment,  some  in  subsequent  series,  and  others  from  written 
reports  prepared  by  the  observers  outside  the  laboratory 
when  the  particular  complex  was  experienced.  These  reports 
are  more  reliable  than  the  usual  answers  to  a  questionary, 
because  they  were  written  down  at  the  time  of  the  experience 
by  trained  observers  who  had  consciously  adopted  the 
attitude  of  psychological  observation.  It  is  from  such 
accounts  that  quotations  are  made  in  all  cases  where  there  is 
no  specific  indication  of  another  source. 

The  procedure  was  to  provide  each  observer  with  a  booklet 
which  contained  space  for  the  description  of  the  various 
processes  mentioned  above.  At  the  beginning  of  the  book 
was  the  following  instruction: 

You  are  requested  to  give  as  careful  an  introspective  description  of  the  various 
complex  organic  processes  listed  herewith  as  possible.  Please  select  a  time  when  the 
particular  process  is  intense,  and  arrange  to  retire  from  distractions  and  write  a  careful 
report  on  these  pages. 

In  the  description  of  the  complex  organic  processes,  the  observer  is  advised  not 
to  avoid  Kundgabe  or  common-sense  language,  but  to  deal  freely  in  the  meanings  of 
processes  as  well  as  in  their  pure  description.  It  is  instructive  to  be  told  that  a  complex 
feels  'as  if  .  .  .'  or  'like.  .  .  .'  In  description,  free  use  should  be  made  of  such  un- 
systematic descriptive  words  as  sharp,  keen,  piercing,  lancing,  thrusting,  insistent, 
dull,  diffuse,  definite,  pungent,  hard,  clear,  bright,  heavy,  full,  steady,  stable,  etc-  It 

1  From  the  Psychological  Laboratory  of  Cornell  University. 

2  'The  Sensations  of  the  Alimentary  Canal,'  Am.  Jour.  Psych.,  26,  1915,  I. 
306 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     3°7 

should  be  borne  in  mind,  however,  that  the  exact  significance  of  such  words  is  not  such 
that  it  always  leads  to  a  clear  and  unequivocal  interpretation,  for  their  meanings  differ 
from  individual  to  individual.  The  sensations  should  therefore,  whenever  possible, 
be  compared  in  quality  with  such  better  known  sensations  as  those  of  the  cutaneous 
and,  possibly,  of  the  kinesthetic  senses.  The  observer  should  also  be  on  the  watch 
for  such  characteristics  as  are  matters  of  extension  or  of  temporal  course,  and  should, 
when  able  to  do  so,  localize  the  complex  as  accurately  as  possible  within  the  body. 

There  were  nine  observers, — six  men  (A,  B,  C,  Z),  E,  F) 
and  three  women  (Jf,  Y,  Z).  Four  of  the  observers  (A,  B, 
X,  Y)  had  received  the  doctorate  in  psychology;  three  of 
these  were  instructors  in  psychology.  Two  others  (C,  Z) 
were  graduate  students.  The  rest  were  undergraduates  in 
the  advanced  courses  in  the  laboratory. 

THIRST 

Observers  A,  B,  and  X  undertook  to  go  without  water  or 
liquid  food  for  long  periods,  and  to  keep  a  running  account  of 
the  experience.  Abstracts  from  their  reports  follow. 

Observer  A. — 6:30  P.M.     Began  experiment. 

9  A.M.  (14^  hrs.)  "Tongue  coated.  Saliva  secreted  rather  freely.  It  is 
rather  that  I  want  a  drink  than  that  I  am  thirsty.  Pressure  and  kinesthetic  complex 
in  my  mouth  (not  throat)  keep  reminding  me  at  intervals  of  the  experiment,  and  I 
imagine  how  a  drink  would  feel." 

2:30  P.M.  (20  hrs.)  Warm  day.  "Have  eaten  a  few  figs.  Saliva  still  quite 
actively  secreted,  and  mouth  and  throat  kept  wet  by  swallowing  frequently  and  licking 
mouth  with  tongue.  Lips  are  getting  dry.  The  thirst  rather  expresses  itself  in  my 
imagination  than  in  sensation  changes.  While  I  am  doing  other  things,  I  suddenly 
break  off  automatically  and  start  for  the  water  faucet,  without  thinking  of  what  I  am 
doing.  Once  I  got  the  water  turned  on  before  I  thought." 

4:30  P.M.     Ate  piece  of  cheese. 

5:30  P.M.  (23  hrs.)  "More  unpleasantness  now.  A  little  more  intense  tactual 
sensations  in  mouth.  Saliva  secretion  seems  less.  Slight  headache.  Number  of 
times  that  I  start  for  faucet  increased;  I  should  think  I  have  started  twenty  times  in  the 
last  hour.  The  start  is  like  this:  I  am  working  and  come  to  a  break  in  the  work;  auto- 
matically I  start  to  get  up  and  move  in  the  direction  of  the  faucet.  The  tactual  sen- 
sations in  the  mouth  and  the  kinesthetic  sensations  in  the  tongue  are  then  in  the  back- 
ground. Then  there  is  usually  a  vague  visual  image  of  a  glass  for  water  or  a  visual 
image  of  the  sink  or  basin  toward  which  I  have  made  my  involuntary  start.  Before 
I  have  moved  more  than  a  bit  with  my  body,  before  I  have  taken  a  step,  I  get  a  kines- 
thetic shock  or  check,  and  remember  the  experiment.  It  then  takes  me  some  time 
to  get  back  to  work.  The  images  of  the  basin  or  faucet  persist.  I  can  not  keep  them 
out  of  mind.  This,  is,  for  the  most  part,  where  the  unpleasantness  comes  in.  The 
unpleasantness  does  not  seem  to  attach  to  the  mouth  sensations  at  all.  The  sensations 
are  not  strong.  They  seem  like  tactual  pressure,  are  superficial,  and  spread  out  over 
the  roof  of  the  mouth.  They  are  not  in  the  cheeks,  on  the  tongue,  or  in  the  throat  back 


308  E.  G.  BORING 

of  the  root  of  the  tongue.    The  weakness  and  paucity  of  mouth  and  throat  sensations  is 
the  striking  thing  so  far." 

n  P.M.    Ate  three  cakes. 

1  A.M.     (30^  hrs.)     "Weak  in  legs.     Headache  partly  gone.    Have  taken  a 
bath  and  am  less  irritable.     Starts  toward  faucet  and  images  of  drinking  less  frequent. 
Roof  of  mouth  very  dry,  an  intense  and  thick  tactual  pressure  with  a  very  little  livelier 
sensation  almost  like  cutaneous  pain  or  the  prickle  that  one  gets  in  drinking  lemonade. 
In  back  of  roof  of  mouth  a  narrow  arch  of  deeper,  duller  sensation,  more  intense,  of  the 
quality  of  muscular  pressure.     Some  time  ago  there  was  mixed  with  this  a  deep,  dull 
pain,  almost  like  a  muscular  cramp." 

10  A.M.  (39/^  hrs.)  "Slight  headache;  tactual  sensations  in  roof  of  mouth; 
tendency  to  keep  licking  roof  of  mouth  and  to  swallow  at  saliva,  which  is  scant  and 
seems  thick.  There  are  frequent  temptations  to  drink,  which  differ  from  the  invol- 
untary starts  for  the  faucet  in  that  they  arise  only  when  the  mouth  sensations  catch 
attention.  Lips  chapped."  At  this  point  the  experiment  was  discontinued. 

Observer  B. — Midnight.  Began  experiment  with  a  drink  of  water.  9  A.M. 
(9  hrs.)  "Tongue  coated.  Feel  as  if  water  would  be  good  for  me,  but  would  taste 
unpleasant.  Not  thirsty.  Mouth  dry  and  sort  of  puckered — drawn." 

9:30  A.M.     Ate  cake  of  almond  chocolate. 

11:30  A.M.     (ii^hrs.)     "Not  thirsty.     Mouth  a  trifle  dry." 

1 130  P.M.  (i3/^  hrs.)  "Beginning  to  get  thirsty.  Thirst  consists  of  sensations 
from  tongue,  roof  of  mouth,  and  throat, — principally  tongue.  Flow  of  saliva  copious. 
I  keep  moving  my  tongue  about  on  roof  of  mouth.  Tongue  and  roof  of  mouth  feel 
sort  of  dead,  when  brought  together.  Mouth  feels  dry,  a  little  bit  drawn  or  puckered. 
There  is  nothing  in  these  complexes  when  I  get  them  clear  but  pressure;  they  mean 
thirst,  i.  e.,  they  tend  to  run  off  into  visual  imagery  of  water  or  kinesthesis  of  going  for 
water.  This  tendency  for  the  focus  to  shift  makes  it  hard  to  keep  the  sensations,  as 
such,  clear.  The  pressures  are  easy  to  refer  below  the  surface,  though  they  remain 
on  the  surface  too.  I  can  feel  the  whole  tongue  affected,  and,  at  times;  this  feeling  does 
not  seem  to  be  pure  pressure,  but  an  ache-like  pressure,  perhaps  muscular  pressure. 
The  ache  is  not  explicit;  I  could  not  analyse  it  out.  The  sensation  is  more  like  the  fore- 
runner of  an  ache.  I  also  feel  a  slight  ache  in  the  back  of  each  jaw,  almost  a  cramp, 
like  the  ache  from  eating  something  too  sour."  B  also  fully  describes  the  impulses  to 
go  for  water  that  were  noted  by  A. 

2  P.M.    Ate  three  slices  of  bread  and  a  little  jam. 

5  P.M.  (17  hrs.)  "Thirst  getting  insistent,  a  puckered,  swollen,  dry  feeling  in 
tongue,  cheeks,  and  roof  of  mouth.  Lips  very  dry.  Also  a  vague  cenesthetic  ache  or 
weakness.  I  am  a  little  unsteady  upon  my  feet,  and  can  not  articulate  with  certainty." 

5:15  P.M.  Ate  piece  of  cheese,  n  P.M.  Ate  a  few  crackers  and  smoked. 
Midnight:  a  few  more  crackers. 

Midnight  (24  hrs.)  "Thirst  insistent.  Consists  merely  of  dry  mouth  (pressure). 
Slight  ache  in  head  and  limbs.  Weak  all  over.  Nothing  new."  The  starts  for  the 
faucet  are  still  reported. 

10  A.M.  (34  hrs.)  "Feel  pretty  good.  Mouth  dry.  Saliva  no  longer  free. 
General  body  aches  diminished.  Impulses  to  get  water  less  frequent." 

10:30  A.M.     Ate  crackers  and  cheese. 

i  P.M.  (37  hrs.)  "Very  thirsty.  Mouth  getting  actually  dry.  Lips  have  to 
be  moistened  constantly.  Impulse  to  get  water  very  strong.  Chief  symptom  is 
general  weakness  and  lassitude.  Going  upstairs  tires  me  out. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     309 

"  I  tried  experiment  of  putting  cracked  ice  in  a  thin  rubber  bag  in  my  mouth.  Just 
as  good  as  a  drink!  However,  pleasant  cold  in  mouth  sets  up  impulse  to  swallow.  If 
I  swallow  it  as  far  as  my  throat,  the  cold  in  the  throat  is  even  more  pleasant  than  that 
in  the  mouth.  This  surprises  me  because  I  have  very  few  thirst  sensations  in  my 
throat  and  ordinarily  do  not  notice  my  throat.  It  is  perhaps  barely  dry  and  aches  a 
little,  but  I  have  no  desire  for  water  there  until  I  put  the  bag  of  ice  water  in  my  mouth. 
The  thirst  disappeared  entirely  as  long  as  the  bag  was  in  my  mouth.  The  bag  even  felt 
wet,  although  it  was  actually  dry.  I  could  not  keep  it  in  long,  however,  because  my 
mouth  soon  ached  from  the  cold.  On  removing  it  the  thirst  returned  immediately. 
As  soon  as  the  ice  in  the  bag  had  melted,  it  ceased  to  be  effective." 

3  P.M.     Ate  buttered  toast  and  ham.     Rather  weak.     B  found  that  two  drops  of 
acetic  acid  on  the  tongue  "tasted  good"  and  relieved  the  thirst  for  7  minutes.    Thirst 
had  returned  in  its  former  intensity  after  15  minutes. 

4  P.M.     (40  hrs.)     "Headache.    Mouth  and  face  warm.     Limbs  ache.     Mouth 
very  dry,  a  dull  pressure  complex,  with  brighter  surface  qualities." 

7  P.M.     Ate  toast,  ham,  and  cheese. 

loP.M.  (46  hrs.)  "Tired,  achy,  weak.  Mouth  almost  parched.  Coated  and  a 
bitter  taste.  Lips  have  peeled  a  little;  feels  as  if  cheeks  might  soon.  Headache." 

2  A.M.  (50  hrs.)  Same  as  before.  The  thirst  is  a  "dry  mouth  (cutaneous  and 
subcutaneous  pressure)  and  a  taste."  The  rain  outside  reminded  B  of  water  and 
prevented  his  sleeping,  so  he  discontinued  the  experiment  at  this  point  with  a  quart  of 
water  and  some  crackers.  The  mouth  tended  to  dry  quickly  after  the  first  drinks,  but 
five  minutes  later  he  was  quite  comfortable.  The  next  morning  there  were  no  notice- 
able effects  of  the  water  fast. 

Observer  X. — 8  A.M.     Began  experiment. 

8  A.M.     (24  hrs.)     "Thirst  began  to  show  itself  by  dryness  of  the  lips.     I  did  not 
clearly  realize  that  I  was  thirsty,  but  found  myself  at  intervals  going  to  the  water  cooler. 
All  along  I  was  being  reminded  that  I  had  certain  sensations  in  my  mouth  that  in- 
dicated thirst  by  finding  the  motor  habit  of  securing  a  drink  set  off.     Later  the  feeling 
of  dryness  extended  beyond  my  lips  to  the  inside  of  my  mouth,  especially  the  roof, 
which  felt  somewhat  as  if  shrivelled.     My  tongue  began  to  feel  changed  in  shape;  it 
seemed  to  be  smaller,  rounder,  rather  swollen  at  the  back.     Later  the  dry,  somewhat 
irritated,  rough  feeling  increased  in  the  roof  of  my  mouth  and  extended  to  my  throat  as 
well.     I  now  feel  as  if  I  had  a  'dry  sore  throat.'     There  are  little  'painy'  sensations  in 
my  throat  and  on  the  upper  surface  of  my  tongue.     My  dry  lips  no  longer  bother  me. 
The  sensations  on  my  tongue  feel  very  much  like  those  that  I  have  after  I  have  scalded 
my  tongue  by  drinking  something  too  hot.     What  moisture  there  is  in  my  mouth 
seems  to  have  got  thick  and  sticky.     The  different  parts  of  my  mouth  have  a  tendency 
to  stick  together  when  I  try  to  spread  them  out." 

4  P.M.  (32  hrs.)  "Mouth  cavity  insistently  calls  attention  to  itself.  Throat 
seems  hot,  and  inflamed,  and  sore;  mouth  somewhat  dry  and  sticky;  tongue  achy  and 
sore.  There  are  dull  pains,  with  perhaps  a  dull  pressure,  localized  inside  the  tongue 
at  its  base.  Dried-up  feeling  on  top  of  tongue."  Experiment  discontinued  at  this 
point. 

Extracts  from  reports  of  thirst  experienced  under  less 
extreme  conditions  by  other  observers  follow. 

Observer  C. — "Dryness  expresses  the  complex  as  a  whole.  The  qualities  seem  to  be 
a  little  warmth,  a  little  pain,  which  is  very  mild  but  seems  to  be  quite  important  as  a 


310  E.  G.  SORING 

component,  and  a  quite  distinct  pressure.  The  pressure  is  like  the  result  of  stretching 
the  skin,  as  if  the  mucosa  had  become  shrunken  and  were  stretched  by  a  too  voluminous 
submucosa.  These  sensations  come  from  the  sides  and  back  of  the  throat  in  the  region 
of  the  uvula,  actually  from  little  more  than  the  soft  palate.  In  the  mouth  there  is  a 
sort  of  stickiness  or  dryness." 

Observer  D. — "  Feeling  of  dryness  in  throat.     Feels  cottony." 

Observer  E. — "A  taut  feeling  of  the  upper  esophagus  and  back  of  throat.  Tongue 
feels  large.  Saliva  thick  and  sticky.  Sort  of  achy  feeling  in  tongue  and  roots,  extend- 
ing to  near-by  parts  of  throat." 

Observer  F. — "Uncomfortable  pressure  in  mouth,  rather  'puckery,'  localized  in 
middle  and  back  of  tongue  and  roof  of  mouth.  Also  a  more  vague  pressure  in  upper 
throat,  not  'puckery.'" 

Observer  Y. — "Light  pressure  in  mouth  cavity  and  soft  palate;  faint  muscular 
pressure  at  junction  of  jaws;  perception  of  wetness  under  tongue  (saliva).  Pressure 
most  prominent.  Later  pressure  sensations  at  junction  of  jaws  and  also  in  cheeks 
became  more  intense  and  clearer.  The  perception  of  'warm-dryness'  in  mouth  was 
less  prominent,  but  by  no  means  obscure.  Finally  general  muscular  sensations  took 
on  a  weak  sort  of  tired  feeling." 

Observer  Z. — After  eating  too  much  candy:  "Tongue  puffy  and  furry,  rather  warm 
and  dry(?).  Strong  imagery  of  glass  of  water,  of  coolness  of  glass  in  hands,  of  coolness 
of  water  in  mouth  and  throat,  and  of  coolness  of  water  in  stomach." 

From  the  foregoing  reports  it  is  evident  that  mild  thirst 
consists  predominantly  in  the  going  to  get  a  drink,  or  in 
imagery  which  anticipates  a  drink;  that  is  to  say,  thirst  may 
not  be  conscious  as  such,  but  may  be  merely  the  meaning  of 
a  complex  situation.  Mild  thirst  is  accompanied  by  a  pres- 
sure-pattern on  the  tongue  and  the  roof  of  the  mouth,  and 
sometimes  by  one  in  the  throat.  This  pattern,  which  is 
seldom  prominent  in  weak  thirst,  becomes  marked  as  thirst 
gets  more  intense.  Then  the  pressures  increase  in  intensity 
and  spread  more  frequently  to  the  throat;  the  saliva  flows 
freely,  and  the  sensations  involved  in  swallowing  it  figure  in 
the  complex.  After  a  longer  period  of  thirsting  (twelve  to 
twenty-four  hours)  the  saliva  no  longer  flows  freely,  the 
mouth  becomes  'thick'  and  'sticky'  and  'dry,'  the  lips  are 
dry  and  have  to  be  moistened  frequently.  The  pressures  of 
the  mouth  are  referred  farther  below  the  surface  and,  at  least 
in  the  case  of  the  tongue,  take  on  the  ache-like-  character  of 
intense  muscular  pressure.  The  oral  sensations  touch  off 
the  desire  to  get  a  drink.  In  a  still  more  extreme  stage,  the 
painful  qualities  become  more  marked  in  the  tongue,  in  the 
roof  of  the  mouth,  and  sometimes  in  the  throat.  There  is 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     3 1 1 

general  bodily  lassitude  and  weakness.  There  is  no  evidence 
of  any  qualitative  peculiarity  other  than  the  pressure-pains 
of  usual  organic  experience.  It  is  the  situation  and  not  the 
specific  quality  that  makes  the  experience  one  of  thirst.  The 
oral  sensations  that  are  typical  of  thirst  are  referred  always 
to  the  mouth  and  sometimes  to  the  throat.  When  they  are 
felt  in  the  throat  they  are  usually  much  less  intense  than 
those  in  the  mouth,  and  some  observers,  even  in  extreme 
thirst,  do  not  find  them  in  this  region  at  all.  Obviously  the 
statement  of  the  textbook  of  physiology,  that  cour  sensations 
of  thirst  are  projected  more  or  less  accurately  to  the  pharynx/1 
needs  revision. 

It  appears  that  the  thirst-perception  in  the  mouth  can  be 
adequately  neutralized,  for  short  times  at  least,  by  a  per- 
ception of  wetness,  even  though  the  wetness  be  illusory. 
Cold  ice-water  in  a  rubber  bag,  which  is  dry  on  the  outside, 
afforded  one  observer  complete  relief.  The  bag  felt  wet, 
like  a  draught  of  cold  water. 

HUNGER 

The  recent  physiological  work  which  has  resulted  in  the 
correlation  of  hunger  with  stomachic  contraction  has  naturally 
suggested  a  tentative  psychological  definition  of  hunger. 
Cannon  and  Washburn2  have  separated  hunger  from  appetite 
and  characterized  the  former  as  an  'ache.' 

"Appetite  is  related  to  the  previous  sensations  of  the  taste  and  smell  of  food;  it 
has  therefore  .  .  .  important  psychic  elements.  It  may  exist  separate  from  hunger 
as,  for  example,  when  we  eat  delectable  dainties  merely  to  please  the  palate.  Sensory 
associations,  delightful  or  disgusting,  determine  the  appetite  for  any  edible  substance, 
and  either  memory  or  present  stimulation  can  thus  arouse  desire  or  dislike  for  food. 

"Hunger,  on  the  other  hand,  is  a  dull  ache  or  gnawing  sensation  referred  to  the 
lower  mid-chest  region  and  the  epigastrium.  It  ...  is  likely  to  grow  into  a  highly 
uncomfortable  pang,  less  definitely  localized  as  it  becomes  more  intense.  It  may  exist 
separate  from  appetite,  as,  for  example,  when  hunger  forces  the  taking  of  food  not  only 
distasteful  but  even  nauseating.  Besides  the  dull  ache,  however,  lassitude  and  drowsi- 
ness may  appear,  or  faintness,  or  headache,  or  irritability  and  restlessness  such  that 
continuous  effort  in  ordinary  affairs  becomes  increasingly  difficult.  That  these  states 

1  Howell,  W.  H.,  'A  Text-book  of  Physiology,'  1908,  272. 

8  Cannon,  W.  B.  and  Washburn,  A.  L.,  'An  Explanation  of  Hunger,'  Amer.  Jour. 
Physiol.,  29,  1912,  441.  See  also  Cannon,  W.  B.,  'A  Consideration  of  the  Nature  of 
Hunger,'  Pop.  Sci.  Mo.,  81,  1912,  291. 


312  E.  G.  BORING 

differ  with  individuals — headache  in  one,  faintness  in  another,  for  example — indicates 
that  they  do  not  constitute  the  central  fact  of  hunger,  but  are  more  or  less  inconstant 
accompaniments,  for  the  present  negligible.  The  dull,  pressing  sensation  is  the  con- 
stant characteristic,  the  central  fact,  to  be  examined  in  detail."1 

Carlson2  also  distinguishes  between  appetite  and  hunger, 
although  he  disagrees  with  Cannon  and  Washburn  in  regard 
to  the  nature  of  appetite.  Hunger  is  pain. 

"Pure  hunger,  not  accompanied  by  'appetite,'  can  be  experienced,  if  during  hunger 
attention  is  fixed  on  the  hunger  pangs  themselves.  .  .  .  When  this  is  done,  hunger  in  its 
various  stages  becomes  different  degrees  of  pain."3 

"It  seems  to  me  that  the  pain  experienced  from  contractures  or  'cramps'  in 
skeletal  muscles  and  in  the  intestines  is  different  from  hunger  pangs,  even  though  pain 
is  inherent  in  hunger.  The  difference  may  be  only  an  apparent  one,  due  to  the  fact 
that  the  latter  pains  arouse  the  memories  of  previous  agreeable  experiences  with  food." 
"It  would  .  .  .  seem  that  hunger  contains  elements  of  kinesthetic  sensation  as  well 
as  pain,  the  latter  predominating  in  strong  hunger."4 

The  observers  in  the  present  experiment  were  asked  to 
report  upon  ' hunger'  only,  under  the  following  instruction: 

"The  observer  is  warned  to  distinguish  between  'hunger'  and  'apptetite.'  Hunger 
is  more  nearly  'sensational'  and  is  said  to  be  always  experienceable  in  isolation  when 
the  attention  is  directed  toward  it.  Hunger  usually  ceases  as  soon  as  food  is  taken. 
Appetite  is  more  'ideational'  and  persists  after  food  is  taken.  It  is  the  desire  for  food, 
the  opposite  of  aversion.  Appetite  probably  constitutes  the  motive  for  eating  dessert 
at  any  meal.  We  are  here  interested  in  the  description  of  hunger  only." 

In  spite  of  this  limitation  the  observers  reported  general 
weakness  and  faintness,  headache,  visual  and  oculomotor 
disturbances,  factors  which  they  recognized,  however,  as 
secondary  to  "hunger  proper."  The  qualitative  nature  of 
the  more  immediately  relevant  experience  may  be  shown  by 
extracts  from  the  reports. 

Observer  A. — At  noon  after  eating  no  breakfast:  "Dull  pressure  of  considerable 
intensity  in  area  above  umbilicus.  With  this  also  pain,  an  achy,  gnawing  pain.  Or 
else  a  muscular  tension,  a  feeling  of  muscular  contraction  in  this  region,  gives  the 
meaning  of  'gnawing.'  I  think  I  sometimes  have  mere  'emptiness,'  i.  e.,  all  this  com- 
plex except  the  gnawing,  achy  pain,  but  this  is  only  a  general  impression.  It  is  common 
for  me  to  say,  'I  am  empty,  but  I  am  not  hungry."' 

1  Pp.  441  f. 

2  Carlson,  A.  J.,  'Contributions  to  the  Physiology  of  the  Stomach.  II.    The  Re- 
lation between  the  Contractions  of  the  Empty  Stomach  and  the  Sensations  of  Hunger,' 
Amer.  Jour.  Physiol.,  31,  1913,  175. 

3  P.  1 86. 

4  P.  189.     For  another  discussion  of  hunger  as  pain,  and  a  resultant  symptoma- 
tology, see  Jones,  A.  A.,  'Hunger  Pain,'  Jour.  Amer.  Med.  Assoc.,  59,  1912,  1154. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     3 1 3 

Observer  C. — "On  the  sensory  side  hunger  is  composed  of  temperature  and  mus- 
cular sensations.  The  temperature  is  warmth,  in  the  main,  but  at  times  there  is  some- 
thing resembling  cutaneous  paradoxical  cold.  What  I  have  called  muscular  sensation 
seems  to  be  a  sort  of  strain  or  pressure,  much  like  that  from  the  contraction  of  any 
skeletal  muscle.  The  localization  is  in  the  stomach,  and  that  organ  feels  as  if  it  were 
pulling  itself  into  a  knot  just  as  the  hand  does  when  the  fist  is  quite  tightly  clenched." 

Observer  D. — "A  dull,  yet  insistent,  ache, — very  diffuse.  It  seems  to  cover  an 
area  of  about  20  cm.  diameter,  fairly  deep,  and  extending  upward  from  the  point 
of  the  sternum.  Sometimes  it  becomes  more  intense  for  an  instant  at  some  point. 
This  point  changes  continually.  At  times  the  diffuse  ache  becomes  weak  and  gives 
way  to  a  sharper  pain,  a  little  higher  up.  This  lasts  about  a  minute  and  then  there  is 
a  return  to  the  previous  conditions." 

Observer  E. — "Hunger  begins  with  an  unpleasant,  uncomfortable  feeling  below 
the  sternum.  This  gradually  and  quickly  changes  to  a  raw  painful  feeling,  as  if  of  the 
rubbing  of  the  two  stomach  walls  together.  This  feeling  of  achy,  rubby  pain  increases 
in  intensity  until  even  the  esophagus  seems  to  be  uncomfortable  in  its  lower  parts." 

Observer  F. — "There  seem  to  be  general  pressures  all  through  the  abdomen,  rising 
up  to  and  above  the  sternum.  They  are  most  definite  in  the  region  just  below  the 
sternum.  They  sometimes  become  a  dull  ache.  (The  whole  thing  is  instable  and 
fluctuates,  coming  and  going  at  almost  rhythmical  intervals.)  They  become  more 
definite  when  the  attention  is  directed  toward  them.  Sometimes  there  is  a  'sharp-hot' 
pain  just  below  the  sternum." 

Observer  X. — After  20  hours' fasting:  "Hunger  is  such  a  'total'  experience  that  it  is 
difficult  to  pick  out  what  should  be  labelled  specifically  'hunger  sensations.'  In  fact, 
I  doubt  if  there  are  any  particular  sensations  that  I  should  label  specifically  such.  I 
call  them  hunger  sensations,  I  believe,  because  I  have  found  regularly  that,  if  I  eat, 
they  disappear.  Otherwise  I  should  be  inclined  to  label  them  as:  a  'weakness'  com- 
plex, or  a  'feeling  of  emptiness,'  or  'throaty  sensations,'  according  as  one  or  another 
aspect  of  the  experience  became  prominent. 

"What  I  feel  at  present  is  (i)  a  general  bodily  weakness,  such  that  I  am  inclined 
to  do  nothing  in  the  way  of  work,  not  even  stand,  and  (2)  a  particular  kinesthetic  com- 
plex in  the  region  of  my  diaphragm.  Perhaps  the  latter  is  also  part  of  the  weakness; 
respiration  certainly  is  not  so  strong  and  deep  as  normally.  There  are  also  (3)  sensa- 
tions which  I  localize  in  my  digestive  tract.  Some  of  these  I  localize  in  my  stomach. 
They  make  up  the  core  of  the  empty,  'gone'  feeling.  They  appear  to  be  vague,  dull, 
quite  persistent  kinesthetic  sensations,  as  if  from  contractions  of  the  stomach.  They 
make  a  definite  peculiar  complex,  but  I  believe  that  it  is  a  complex  composed  of  pres- 
sures and  kinesthesis, — dull,  but  definite;  very  strong  and  insistent  at  times,  but  never 
sharp  or  bright  or  clean-cut.  Besides  the  sensations  in  the  stomach,  there  are  others, 
localized  in  the  back  of  my  throat,  at  the  beginning  of  my  esophagus,  which  seem  like 
incipient  swallowing  movements  (esophageal  kinesthesis).  They  draw  my  attention 
very  decidedly  to  that  region;  when  I  attend  to  them  there  is  a  veiy  strong  inclination 
(in  visual  and  kinesthetic  terms)  to  put  food  in  my  mouth.  The  thought  of  food  seems 
to  make  the  salivary  glands  more  active,  so  that  I  occasionally  actually  swallow.  The 
upper  part  of  my  digestive  tract  seems  very  ready  to  react,  and  is  evidently  incipiently 
active, — judging  from  the  sensations.  The  feeling  of  'wanting  something'  is  localized 
in  my  throat.  The  throat  sensations  are  quite  steady  and  persistent." 

Observer  Y. — "Strong,  gnawing  pressure  (gnawing  is  elemental,  a  kind  of  pain). 
This  complex  is  unpleasant  and  means  a  need  of  food, — hunger.  There  is  also  a  com- 


3H  E-  G.  BORING 

plex  localized  in  the  pharynx,  and  muscular  sensations  in  the  jaws.  Also  a  perception 
of  wetness,  localized  under  the  tongue,  meaning  much  saliva.  The  complexes  localized 
in  the  stomach  and  pharynx  together  make  up  the  desire  for  food.  The  pharyngeal 
complex  is  the  less  prominent." 

Observer  Z. — This  observer  reports  that  she  seldom  has  the  intense  and  vivid 
'  hunger  of  childhood '  and  that  she  has  been  unable  to  induce  it  for  the  sake  of  the  experi- 
ment. In  addition  to  describing  general  faintness,  however,  she  gives,  after  a  short 
fast,  and  under  the  caption  'Emptiness,'  the  following  report.  "Slight  headache 
and  light  feeling.  No  desire  for  food  as  food,  but  knew  from  experience  that  it  would 
take  away  the  'empty'  feeling.  Experience  a  slightly  unpleasant  pressure,  localized 
in  bottom  of  stomach;  pressure  in  throat  from  about  larynx  to  top  of  back  of  mouth; 
pressure  of  tongue  on  roof  and  sides  of  mouth  (I  think  this  is  thirst);  tongue  felt  bigger 
and  softer  than  usual.  The  pressure  on  the  bottom  of  the  stomach  seemed  just  like 
the  pressure  of  a  heavy  weight  on  a  relaxed  muscle,  although  it  was  not  so  intense." 

The  writer  has  described  elsewhere  a  case  in  which  hunger 
was  induced  in  one  subject  by  the  introduction  of  HC1  into 
the  stomach.1  A  few  sentences  will  suffice  to  show  that  this 
' laboratory  hunger'  does  not  differ  from  that  occurring  under 
more  usual  conditions. 

Observer  B.  After  5  c.c.  of  5  per  cent.  HC1:  "Hunger,  a  strong,  intense,  diffuse 
ache,  varying  in  intensity  and  covering  an  area  as  shown  [i.  e.,  an  area  extending  from 
the  umbilicus  to  the  sternum].  There  is  an  especially  intense  and  achy  spot  at  [a  point 
a  little  above  the  umbilicus  and  to  the  left].  Hunger  goes  and  then  returns;  then  lasts 
a  long  time,  getting  gradually  fainter." 

In  another  trial,  a  warmth  was  reported  to  "die  away  very  slowly,  fusing  into  a 
general  ache  in  the  stomach  region.  This  ache  gets  more  intense  and  presently  without 
qualitative  change  turns  into  hunger." 

Again,  a  'stinging  pain'  is  supplemented  by  a  'dull  ache'  below  the  sternum. 
"The  ache  spreads  downwards,  and,  as  the  sting  disappears,  it  turns  into  hunger  pains. 
The  hunger  pains  are  marked,  but  are  shot  through  by  a  little  stinginess,  a  brighter 
and  more  tingling  pain." 

The  hunger-complex  is  a  complex  of  pressure  and  pain. 
Upon  a  background  of  dull  pressure  (A,  B,  C,  F,  X,  Y), 
which  is  sometimes  recognized  definitely  as  kinesthesis  or  the 
equivalent  muscular  pressure,  there  is  set  a  dull  ache  or  gnaw- 
ing pain  which  characterizes  the  hunger  (A,  B,  D,  E,  F,  Y\ 
the  intense  muscular  pressure  of  C  is  also  pain;  muscular 
pressure  goes  over  into  ache-like  pain,  which  observers  often 
call  pressure).2  Two  observers  (X,  Z),  who  failed  to  find  the 
pain-quality,  also  had  difficulty  in  determining  just  what 

1  Op.  cit.,  48. 

2  Cf.  the  confusion  of   pressure,  strain,  cramp,  and  pain  in  the  introspections  of 
esophageal  pressure,  especially  those  of  G,  op.  cit.,  28  ff. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     3  r  5 

constituted  hunger.  Both  pain  and  pressure  are  referred 
to  the  region  of  the  stomach.  The  pain  is  noted  as  fluctu- 
ating, as  rhythmical,  as  instable.  In  more  intense  hunger 
the  maxima  of  the  fluctuations  of  the  'dull  ache'  may  involve 
a  sharper  pain-quality,  which  is  definitely  localized  and  limited 
to  a  very  small  area  (B,  D,  F).  'Emptiness'  appears  to 
consist  of  the  typical  pressure  pattern  of  hunger  without  the 
algesic  components  (A,  Z).  Three  observers  (Jf,  Y,  Z1) 
describe  a  complex  kinesthesis  in  the  throat  and  of  oral 
sensations  arising  from  the  free  flow  of  saliva,  a  complex 
which  means  for  them  desire  for  food,  appetite,  a  literal 
watering  of  the  mouth.  Here  we  have  the  true  sensory 
basis  of  'appetite.'  The  ideation  of  food  (mentioned  speci- 
fically by  X)  is  no  doubt  a  usual  concomitant,  and  presumably 
it  often  constitutes  a  desire  for  food  that  lacks  sensory  com- 
ponents entirely.  There  can  be  no  question  that  this  desire 
for  food  —  appetite,  if  one  is  not  disposed  to  limit  the  term  too 
closely  —  may  also  often  be  unconsciously  carried,  just  as  in 
thirst  the  'appetite'  for  water  may  become  manifested  auto- 
matically in  the  movements  of  going  for  a  drink  (see  pp.  307, 


Our  reports  enable  us  to  supplement  Cannon's  description  by  many  reports  of 
psychologically  trained  observers.  But  we  have  gone  farther  than  confirmation. 
Hunger  is  a  twofold  experience.  It  is  pressure  in  its  weak  form,  pain  and  pressure 
when  intense.  If  one  calls  the  intense  experience  'hunger'  and  the  weak  'emptiness,' 
one  has  changed  the  phraseology  but  not  the  fact.  Moreover,  weak  hunger  appears 
to  be  muscular  pressure,  and  intense  hunger  is  the  ache  of  intense  muscular  pressure. 
Carlson,  we  have  seen,  has  also  made  this  point:  'hunger  contains  elements  of  kines- 
thetic  sensation  as  well  as  pain'2;  but  he  thinks  that  the  pain  is  not  'the  pain  experienced 
from  contractures  or  'cramps'  in  skeletal  muscles.'3  However,  Carlson  admits  that 
the  difference  may  be  extrinsic  rather  than  intrinsic,  and  he  will  doubtless  welcome 
evidence  for  the  muscular  quality  of  the  entire  hunger-pattern. 

It  is  not  easy  to  follow  Carlson  in  his  discussion  of  appetite.4  He  objects  to  the 
view  that  'appetite  requires  a  nervous  organization  capable  of  associative  memory,' 
because  we  have  "in  appetite  for  food  conditions  as  primitive  and  essentially  fixed  by 

1  The  three  woman:  but  it  would  be  overhasty  to  discover  a  sex  difference.    They 
found  in  general  more  difficulty  in  deciding  just  what  hunger  was  —  perhaps,  after  all, 
their  sex  is  a  little  less  intimate  with  the  inner  man  —  and  they  gave  fuller  descriptions. 
Unable  to  find  a  sine  qua  non,  they  described  all  possible  concomitants.     Of  course 
they  thus  noted  complexes  which  the  men  overlooked. 

2  Op.  cit.,  190. 

189. 


316  E.  G.  BORING 

inheritance  as  in  the  case  of  the  sexual  desires  or  'instincts'."  Appetite  becomes  'the 
desire  for  food,'  'the  expression  of  an  inherited  mechanism.'  "The  inheritance  factor 
in  appetite,  the  desire  to  eat,  is  in  some  way  caused  by  the  hunger  pains."  When 
appetite  apparently  occurs  alone,  it  is  due  to  a  concomitant  'subconscious  hunger.' 
Three  factors  make  up  the  food-taking  impulse:  hunger  (pain),  appetite  (desire  for 
food;  a  sensation?),  and  'memories  of  the  taste  and  smell  of  foods.'  There  would  ap- 
appear  to  be  seven  possible  cases:  (i)  hunger  alone  (pain),  when  one  attends  to  the 
hunger  sensations;  (2)  hunger  and  desire  for  food  (pain -f- appetite),  when  in  extreme 
hunger  one  eats  disgusting  food;  (3)  desire  alone  (subconscious  hunger  pains+appetite), 
the  non-rhythmical  'hungry-feeling'  of  Carlson's  subject;  (4,  5,  6)  any  of  these  states 
together  with  'memories'  of  food — the  usual  impulses  in  food-taking;  (7)  'memories' 
alone,  'the  contemplation  of  a  favorite  dish  after  a  full  and  satisfying  meal.'  So  much 
we  are  told.  But  we  have  no  hint  as  to  the  nature  of  appetite.  Is  it  a  sensation?  is 
it  a  group  of  sensations?  if  so,  what  is  it  like?  We  do  not  ask  for  technical  psychology. 
If  it  is  sensory,  what  makes  it  so  fundamental  that  it  must  be  reflexly  aroused?  And 
why,  in  particular,  must  hunger,  already  defined  as  'different  degrees  of  pain,'  be  its 
sole  condition?  And  what  is  this  conditioning  hunger,  conscious  and  'subconscious'? 
Is  it  sensation?  or  is  it  the  nervous  substrate  of  sensation?  or  is  it  the  physiological 
cause  of  the  hunger  pangs?  Until  these  questions  are  answered  Carlson's  distinctions 
will  prove  of  little  service. 

If,  however,  classification  and  definition  in  such  a  simple  case  are  wanted,  the 
writer  would  suggest  the  following  schema: 


Hunger-complex 


Desire  for  food 


Hunger  =  muscular  pain 

Emptiness  =  muscular  pressure 

Appetite  =  throat-mouth  sensations 

Imaginal  desire      =  imagery 
Unconscious  desire  =  determining  tendency 


Sensory 

Imaginal 
Neural 


It  seems  probable  that  such  an  account  would  be  accepted  by  Meumann,1  who  has 
laid  stress  upon  the  variety  of  the  digestive  sensations.  Meumann  describes  three 
typical  digestive  experiences.  In  the  first  place  there  is  the  'hunger  sensation,'  which 
'is  localized  not  only  in  the  mouth  and  in  parts  of  the  throat,  but  also  quite  definitely 
in  the  stomach,' z  a  complex  equivalent  to  hunger  plus  appetite  as  given  above.  In  the 
second  place,  there  is  'the  very  characteristic  sensation  of  emptiness  of  the  stomach/ 
a  sensation  which  "has  a  very  different  character  from  the  tension  or  pressure  sensation 
of  the  abdominal  wall.  It  can  become  intensified  in  a  very  unpleasant  way  and  is 
sometimes  connected  with  a  vague  perception  of  the  peristalsis  of  the  stomach."* 
just  such  a  complex  we  have  also  called  'emptiness.'  Finally,  after  eating,  there  is  'a 
characteristic  sensation  of  fullness  and  pressure  in  the  stomach'  or,  as  it  is  called  in 
another  place,  'satisfaction  and  fullness.'4  The  experience  is  said  to  be  not  one  of 
mere  extension,  as  it  is  partially  independent  of  the  amount  of  food  taken,  and  to  some 
extent  dependent  upon  the  kind  of  food.  Our  introspections  do  not  cover  this  point. 
Hertz  has  described  the  experience  and  concluded  that  it  is  conditioned  upon  the 

1  Meumann,  E.,  'Zur  Frage  der  Sensibilitat  der  inneren  Organe,'  Arch.  /.  d.  ges. 
PsychoL,  9,  1907,  28ff.;  'Weiteres  zur  Frage  der  Sensibilitat  der  inneren  Organe  und 
der  Bedeutung  der  Organempfindungen,'  ibid.,  14,  1909,  279  ff. 

z  Arch.,  9,  52. 

3  Arch.,  14,  293. 

4  Arch.,  9,  51  f.;  14,295.    The  writer  does  not  interpret  Meumann  as  meaning  to 
distinguish  between  'fullness'  and  'satisfaction,'  although  it  is  possible  to  make  such  a 
construction. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     3 1 7 

tension  of  the  muscular  coat  of  the  stomach,  a  tension  of  which  the  effectiveness  is 
independent  of  muscular  tonus.1  Sternberg,  it  should  be  noted,  distinguishes  between 
appetite,  hunger,  and  satisfaction.2 

NAUSEA 

Nausea  was  experimentally  induced  in  the  laboratory  by 
the  administration  of  syrup  of  ipecac  or  by  a  decoction  of 
tobacco  and,  in  one  case,  by  the  smell  of  castor  oil. 

Numbers  below  in  brackets  indicate  the  time  in  minutes  that  has  elapsed  since  the 
beginning  of  the  experiment. 

Observer  A. — 2  teaspoonfuls  syrup  of  ipecac.  [23]  "Breathing  sensations  queer. 
Feeling  like  that  of  respiration  in  abdomen,  but  shorter  and  quicker  than  breathing. 
I  feel  as  if  I  were  'ready  to  vomit,'  which  is  a  meaning.  My  stomach  feels  a  bit  fuller. 
The  tone  of  my  muscles  in  arms,  chest,  and  abdomen  seems  to  have  gone  down;  I  feel 
weaker."  Q.  "Is  this  nausea?"  A.  (after  thinking):  "Yes  .  .  .  Saliva  is  forming. 
Tendency  to  open  my  mouth.  Sweat  comes  on.  Contractions  of  stomach,  almost 
painful.  Breathing  is  irregular.  I  close  my  eyes.  [He  vomits  five  times.]  Big 
muscular  wrench.  Characteristic  muscular  weakness.  Weeping.  Throat  and 
stomach  feel  full.  Achy  pains  across  stomach.  I  think  I  feel  most  nauseated  just  be- 
fore I  vomit.  It  feels  as  if  my  stomach  actually  sank.  To  the  best  of  my  knowledge 
that  is  like  muscular  pressure.  There  was  a  very,  very  slight  dizziness  in  my  head." 

Observer  D. — 4  teaspoonfuls  syrup  of  ipecac,  [i]  "Begin  to  feel  something.  A 
sort  of  sharp  ache  under  sternum."  [3]  "Dull,  heavy  ache  around  stomach  region." 
[15]  "Something  runs  the  whole  length  of  my  esophagus,  up  to  the  back  of  my  throat; 
it  means  a  desire  to  vomit.  ...  It  is  taking  on  a  nauseous  character.  I  feel  it  mostly 
in  the  back  of  my  throat;  it  seems  to  spread  all  over  from  the  stomach  up;  considerable 
pressure  to  it.  [He  vomits  violently.]  Felt  just  as  if  there  was  a  pressure  there  at 
bottom  of  esophagus  up  to  throat.  .  .  .  Now  I  am  getting  unsettled  in  stomach.  This 
seems  to  be  a  diffused  pain,  localized  at  least  two  inches  below  sternum.  With  it  there 
is  pressure,  which  means  nausea  and  which  gets  more  intense,  meaning  impending 
vomiting."  [21 :  vomits  again.]  "Just  preceding  the  vomiting  the  pressure  gets  very 
intense.  It  seems  as  if  that  pressure  forced  the  contents  right  out.  While  vomiting 
I  felt  violent  contractions  in  my  stomach.  .  .  .  Nausea  is  coming  again  now.  The 
first  thing  is  pain.  It  is  now  at  the  top  of  my  stomach  [indicates  level  of  sternum] 
and  now  lower  down.  There  is  also  a  band  of  pressure,  below  the  sternum.  Rather 
suggestive  of  gripes."  Q.  "What  sort  of  pain  is  this  pain  that  comes?"  A.  "Diffuse, 
sort  of  dull.  It  gets  very  intense.  Not  the  pain  of  a  prick  at  all.  It  seems  as  if  the 
pain  and  the  pressure  constitute  nausea.  The  pressure  alone  means  incipient  vomiting. 
...  In  some  ways  the  pain  is  more  of  an  ache  than  a  pain;  I  suppose  an  ache  is  a  dull 
pain.  It  is  quite  diffuse."  [40:  vomits.]  "Frightful  unpleasantness  seems  to  cover 
up  everything.  There  is  a  bodily  trembling — a  general  feeling  of  weakness." 

1  Hertz,  A.  F.,  'The  Sensibility  of  the  Alimentary  Canal,'  1911,  19  ff. 

2W.  Sternberg's  classification  is  into  (i)  disgust,  (2)  appetite,  (3)  hunger,  (4) 
thirst,  (5)  feeling  of  satisfaction;  'Der  Hunger,'  Zentralbl.  /.  Physiol.,  23, 1909, 105.  For 
his  distinction  between  hunger  and  appetite,  see  in  particular:  'Physiologische  Psychol- 
ogic des  Appetits,'  Zeitschr.f.  SinnesphysioL,  44,  1910,  254:  'Das  Appetitproblem  in  der 
Physiologic  und  in  der  Psychologic,'  Zeitschr.f.  PsychoL,  59,  1911,  91. 


318  E.  G.  BORING 

Observer  Y. — 5  teaspoonfuls  syrup  of  ipecac.  [15]  "Dizziness.  Pressure  sensa- 
tions in  stomach, — a  dull  pressure,  unpleasant,  slightly  nauseating,  a  sort  of  gnawing, 
a  sickish  character.  Pressure  gives  a  sinking  feeling.  Occasionally  muscular  sensa- 
tions, as  if  I  were  about  to  vomit."  [20:  vomits.]  "I'm  not  sick  or  squeamish;  it  was 
muscular."  [22]  "  I  am  sick  now.  A  gnawing,  sinking,  pressure-like  quality  in  stomach 
region,  extending  up  a  little  under  sternum.  A  trifle  dizzy,  but  the  stomach-complex 
is  strongest.  Pressure-like  quality  seems  to  irradiate  from  the  stomach,  and  I  feel 
generally  squeamish.  The  feeling  extends  all  over  me."  [24:  vomits  5  times.] 
"Nausea  got  very  strong  before  vomiting.  Muscular  sensations  are  part  of  it.  They 
were  fused  with  a  'sinking/  which  got  worse  and,  as  it  got  worse,  gnawing."  [25: 
vomits  twice.]  "I  do  not  know  whether  the  sinking,  gnawing  quality  is  something  new 
in  the  element-line  or  not,  or  whether  it  is  the  character  of  the  total  complex.  It 
belongs  to  the  pressure  family.  It  may  be  that  there  is  a  dull  pain  or  ache,  although 
it  is  not  what  I  usually  mean  by  an  ache.  It  might  be  an  approach  to  a  fused  non- 
intensive  ache.  Certainly  its  identity  as  such,  if  such  it  is,  is  so  merged  in  pressure, 
that  it  appears  more  like  a  coloring,  a  dull,  gnawing,  sinking  affair.  I  am  rather 
inclined  to  think  that  the  'gnawiness'  is  in  part  of  the  achy  character,  but  that  pressure 
is  the  clear  and  stronger  component.  It  is  all  closely  fused — a  unique  whole."  [35] 
"The  gnawing  is  more  prominent  than  the  sinking.  Yes,  it  is  something  aching;  I  am 
quite  sure  now.  It  is  dull  pain,  very  different  from  pin-prick,  and  yet  something  of 
the  same  order, — at  least,  a  pain.  .  .  .  The  achy  character  is  more  prominent  than 
cbefore — a  gnawing." 

Observer  Z. — 6  teaspoonfuls  syrup  of  ipecac.  [36:  vomits  several  times.]  "Feel 
awfully  funny  in  throat;  the  muscles  feel  all  tight,  and  yet  the  throat  feels  as  if  it  were 
bigger  than  usual.  I  think  that,  except  when  I  felt  the  contents  coming  up,  I  did  not 
have  any  sensations  at  all  below  the  bottom  of  my  neck."  Q.  "Would  you  say  you 
were  nauseated?"  A.  "No,  I  do  not  think  I  was.  Generally,  as  well  as  I  can  re- 
member, nausea  is  decidedly  unpleasant  in  both  stomach  and  throat."  Z  failed  to 
get  any  nausea  within  an  hour  and  went  home.  There  she  became  quite  sick  (i.  e.y 
vomited)  during  the  night,  and  recorded  at  one  time  the  following:  "Vague  moving 
pressures,  localized  in  stomach.  Slight  dizziness  and  weakness.  Spasmodic  contrac- 
tion of  muscles  over  whole  trunk,  especially  in  throat.  Tears;  perspiration."  She  did 
not  record  at  the  time  whether  or  not  the  complex  was  one  of  nausea,  although  in  the 
morning,  upon  being  questioned,  she  was  inclined  to  think  that  it  was. 

In  order  to  obtain  a  nausea  which  would  be  more  persistent 
than  that  induced  by  the  ipecac,  two  observers  took  doses  of  a 
strong  solution  of  tobacco  juice. 

Observer  B. — 2  teaspoonfuls  of  tobacco  juice.  [5]  "Esophageal  sensations,  weak, 
but  qualitatively  like  those  in  swallowing  a  hard  object.  Faint  pressure  in  stomach, — 
a  very  vague  ache."  [15]  "Gentle  achy  pressure  in  stomach  region.  Also  vague  aches 
from  arms,  like  muscular  fatigue.  Whole  thing  makes  up  'sick  feeling.'  Attention 
to  any  one  part  seems  to  break  it  up."  [19]  "When  I  smell  the  tobacco  juice,  a  wave 
of  achy  pressure  travels  down  the  esophagus.  It  is  nauseous."  [24]  "It  seems  as  if 
nausea  were  in  this  case:  general  bodily  weakness  (mostly  muscular  fatigue) -(-headache 
(swimming  sensations,  eye-pressure-aches,  tightness  at  ear,  pressure  wave  at  back  of 
head;  eye-aches  and  swimming  most  promment-\- intense  unclear  pressure-aches  around 
sternum.  It  seems  as  if  stomach  sensations  had  to  be  unclear  in  nausea;  attention 
to  them  spoils  the  complex  as  nausea."  [37]  "Incipient  vomiting  sensations,  in 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     3  r9 

which  stomach-aches  get  more  intense  and  extend  up  farther  and  aches  in  eyes  get 
intense.  This  u  nausea.  I  also  sometimes  get  stomach-pressures,  which  mean  in- 
cipient vomiting,  but  which  are  less  achy."  [80]  "The  nausea  is  particularly  difficult 
to  localize;  it  is  fleeting,  evanescent,  by  which  I  think  I  mean  merely  that  it  (or  at  least 
the  achy  complex)  is  intermittent.  Attention  always  goes  naturally  to  the  head 
sensations.  When  I  voluntarily  attend  to  the  stomach-sensation,  it  always  turns 
out  to  be  an  ache;  and,  since  it  seems  to  remain  as  continuous  as  any  process  in  changing 
from  obscure  to  clear,  I  say  that  achiness  is  its  normal  character.  But  attention 
never  goes  voluntarily  to  these  sensations.  I  say  they  are  essential  because  I  always 
find  them  when  I  hunt  for  them  while  I  am  feeling  nauseated.  The  principal  part  of 
the  nausea  as  regards  intensity  and  clearness  is  the  headache,  swimming,  and  (just 
now)  jaw-aches  (crampy  character);  but  I  do  not  think  that  they  could  be  nausea 
without  being  supplemented  by  the  stomach  sensations,  i.  e.,  I  think  the  stomach-com- 
plex gives  the  meaning  nausea." 

Observer  E. — 2  teaspoonfuls  of  tobacco  juice,  50  per  cent,  dilution.  [7]  "I  begin 
to  feel  quite  sick  now, — a  sort  of  dizziness  in  head;  also  pressure  in  stomach.  Feeling 
of  great  discomfort  all  the  way  up  from  stomach  to  throat.  More  intense  at  times. 
Also  a  little  pain,  a  peculiar  ache,  a  sort  of  dry  achy  tenseness.  It  is  very  intense  every 
time  I  smell  the  tobacco.  Also  a  dull  ache  in  head."  [n]  "Convulsive  movements  in 
the  stomach  or  esophagus."  Q.  "Would  you  say  you  were  nauseated?"  A.  "Yes." 
[20]  "Still  a  discomfort  in  stomach.  It  is  almost  pain."  [165]  "Feel  sick  in  my  throat. 
There  are  aches  in  my  stomach." 

Of  all  the  observers,  A  had  the  greatest  difficulty  in  char- 
acterizing nausea.  The  nausea  described  above  (ipecac)  for 
him  was  not  intense  nor  was  it  probably  typical.  The  strong, 
characteristic  experience  could  invariably  be  induced,  how- 
ever, by  the  smell  of  castor  oil.  His  introspections  under  these 
conditions  follow. 

Observer  A. — Nausea  induced  by  smell  of  castor  oil.  "With  the  smell  of  the  oil 
there  was  a  big  shiver,  together  with  a  wave  of  cold,  all  over  my  upper  chest  and 
abdomen — even  in  my  arms.  There  was  a  sensation  which  has  something  in  it  of  the 
sinking  sensation  that  you  get  down  here  [umbilicus  to  sternuml  when  you  drop  in  an 
elevator.  There  is  also  a  start  of  a  vomiting  reflex,  a  muscular,  pressury  sensation;  it 
seems  as  if  I  could  feel  a  contraction.  There  is  a  bit  of  dizziness  in  head  also.  I  feel 
myself  sweating  a  bit.  .  .  .  Both  what  is  the  start  of  a  vomit  and  the  sinking  thing  are, 
I  think,  pressury.  .  .  .  The  pressure  in  the  stomach  region  is  a  pressure  down."  After 
another  trial:  "I  do  believe  that  there  is  something  that  I  haven't  mentioned  yet,  a 
sensation  which  forms  a  part  of  this  whole  situation.  It  is  very  hard  to  localize;  cer- 
tainly, however,  somewhere  in  the  trunk.  I  can  describe  it  only  as  a  sickening  sensa- 
tion, a  kind  of  an  awfulness  and  helplessness.  It  is  not  intense,  if  you  can  talk  about 
its  intensity  absolutely.  The  other  things  were  definite  and  stood  there  and  waited 
for  you;  they  caught  your  attention.  This  sensation  is  there  beside, — a  sickening,  an 
awful  helplessness."  At  another  time  A  assumed  the  attitude  which  stands  for  this 
'awful  helplessness:'  the  body  is  relaxed,  the  knees  slightly  flexed  and  the  arms  hanging 
limp,  the  body  bends  slightly  forward,  the  abdomen  in,  the  head  is  inclined,  the  mouth 
is  open,  the  eyes  are  closed.  After  another  experiment:  "I  don't  know!  If  it  is  a  mean- 
ing, it's  the  meaning  of  the  smell.  And  how  can  the  meaning  of  the  smell  be  down  in 


320  E.  G.  BORING 

my  chest  and  abdomen — for  that  is  where  I  feel  sick?  This  is  the  case:  I  do  feel  sick. 
And  I  feel  sick  down  here.  Now  there  are  a  lot  of  sensations  down  here  that  I  can  put 
my  finger  on  and  localize." 

The  confusion  of  the  ache  of  nausea  with  the  ache  of 
hunger  came  out  in  the  experiments  that  were  made  upon  B 
with  stimulation  by  HC1  (cf.  p.  314). 

Observer  B. — After  the  introduction  of  5  c.c.  of  20  per  cent.  HC1  into  the  stomach. 
"Ache  in  stomach  region  became  definite  and  was  recognized  as  nausea.  It  was  most 
intense  about  3  cm.  below  sternum.  The  nausea  lasted  a  long  time  (I  still  feel  a  little 
bit  sick.)  It  is  a  pain,  very  much  like  hunger."  After  5  c.c.  of  5  per  cent.  HC1: 
"Nausea.  I  feel  pretty  sure  that  'sickness'  is  the  nausea  ache  below  the  sternum  plus 
muscular  pressure  down  toward  the  umbilicus,  the  latter  meaning  violent  contractions, 
as  if  I  were  going  to  vomit.  I  do  not  believe  that  the  ache  is  in  any  way  different  from 
the  ache  of  hunger,  except  that  it  is  a  little  more  diffuse,  a  little  higher  up,  less  likely 
to  be  localized  and  less  definitely  localized  when  it  is,  less  intense,  and  without  the 
rhythmical  intensive  fluctuations  of  hunger." 

Observer  D  volunteered  a  general  statement  that  is  relevant:  "I  can  not  always  tell 
hunger  from  nausea.  When  I  am  nauseated  [he  is  subject  to  spells  of  indigestion]  I 
generally  stop  eating.  At  such  times  I  decide  to  begin  with  my  meals  again  as  soon  as 
I  feel  hungry,  but  I  can  not  always  tell  when  to  start  in,  because  I  can  not  always  tell 
whether  I  am  hungry  or  still  nauseated." 

The  reports  show  that  the  experience  of  nausea  is  very 
complex  indeed.  All  sorts  of  factors  are  mentioned:  dizziness 
or  swimming  sensations  in  the  head,  the  sensations  aroused 
by  too  free  a  perspiration,  aches  and  pressure-pain  complexes 
in  the  head,  in  the  eyes,  in  the  jaws,  in  the  arms,  general  bodily 
shivers  and  chills,  general  weakness.  Besides  these  factors, 
which  sometimes  constitute  the  most  prominent  part  of 
nausea,  there  are  the  sensations  which  are  referred  to  the  ali- 
mentary tract  proper.  Pressure-complexes  referred  to  the 
stomach,  or  pressure-waves  localized  in  the  esophagus, 
indicate  incipient  vomiting  and  are  often  present.1  Other 
alimentary  pressure-sensations,  however,  appear  to  be  more 
nearly  integral  to  nausea:  the  'sinking  feeling'  and  the  dull 
'sickishness'  are  described  as  purely  pressure,  the  '  gnawing 
pressure'  and  even  the  'ache'  are  probably  partly  pressure. 
With  the  exception  of  Z,  in  whom  the  occurrence  of  a  true 
nausea  is  open  to  doubt,  and  of  A  in  his  series  with  castor-oil, 

1  It  is  this  complex,  apparently,  that  E.  Murray  describes  as  'revulsion  .  .  . 
sometimes  grading  into  a  feeling  of  nausea'  ('Organic  Sensation,'  Amer.  Jour.  PsychoL, 
20,  1909,  437).  To  Murray  belongs  the  credit  of  having  obtained  introspections  upon 
nausea  under  experimental  conditions.  Unpleasant  odors  were  used  as  stimuli. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     Z21 

all  the  observers  agree  that  nausea  involves  a  dull  ache  or 
pain  in  the  stomachic  region.  Two  observers  (B,  D)  declare 
that  this  ache  is  indistinguishable  in  quality  from  the  pain  of 
hunger,  and  one  (Y)  implies  the  similarity  by  describing  it  at 
first  as  a  'gnawing  pressure'  and  coming  later  to  the  con- 
clusion that  it  was  an  'ache.' 

Which  of  these  factors  are  essential  to  nausea,  and  which 
are  occasional  concomitants?  Dizziness,  headache,  bodily 
weakness,  shivers,  perspiration,  and  so  forth  are  by  no  means 
invariably  present.  No  one  is  essential,  and  all  may  be 
absent.  They  occur  more  frequently  as  concomitants,  or 
perhaps  indicators,  of  an  intense  nausea.  The  pressures  of 
the  vomiting  reflex  are  often  absent,  and  were  distinguished 
by  most  of  the  observers  as  separate  from  nausea.  Their 
concurrence  seems  to  be  only  casual;  they  have  not  come  to 
mean  nausea.  Frequently  they  occur  without  nausea  in 
vomiting.1  The  pressures  of  the  'sinking  sensation'  and  the 
dull  ache  seem  to  be  the  most  constant  components;  but  the 
pressures  are  lacking  in  the  hunger-like  nausea  that  B  reports 
for  stimulation  by  HC1,  and  the  pain  is  not  found  by  A  in  the 
intense  nausea  induced  by  castor  oil.  Apparently,  then, 
there  is  no  sensory  factor  that  is  invariably  present  in  nausea. 
The  facts  become  intelligible  if  we  regard  nausea  as  a  meaning, 
a  situation.  Various  organic  factors,  alimentary  or  general, 
may  combine  in  nausea,  or  (at  least  after  the  more  complex 
experience  has  been  had)  a  few  or  even  one  of  the  more  usual 
constituents  may  mean  the  whole  situation.  Nausea  for 
different  persons,  or  for  the  same  person  at  different  times, 
may  thus  be  very  different.  The  significance  of  the  nauseous 
situation  is  such  that  one  is  not  likely  to  adopt  even  a  casually 
introspective  attitude  toward  it;  hence,  even  if  there  are  varia- 
tions from  time  to  time  in  the  same  person,  the  qualitative  diff- 
erences are  still  not  likely  to  be  noticed.  Nausea  involves  a 
condition  of  the  digestive  tract,  and  undoubtedly  the  ali- 
mentary pattern  of  pressure  and  ache  is  the  usual  result  of 

1  In  the  present  experiment  both  A  and  Z  vomited  without  nausea.  In  the 
experiments  previously  reported  by  the  writer  (op.  cit.)  nausea  was  as  infrequent  as 
vomiting  was  common.  Observer  F  in  that  experiment  was  almost  never  nauseated; 
but  see  the  account  of  vomiting  on  pp.  6  and  12. 


322  E.  G.  BORING 

the  conditions  which  produce  nausea.  In  a  hypoalgesic 
individual,  nausea  may  never  reach  the  ache-stage.  By 
association  with  the  pressure-ache  complex,  or  with  what 
may  by  a  given  person  be  regarded  as  symptoms  of  nausea 
(e.  g.,  vomiting,  loss  of  appetite,  disgust,  weakness,  etc.), 
other  sensations  may  come  to  stand  for  the  nausea  or,  in  a 
given  case,  to  constitute  the  habitual  form  of  nausea. 

The  foregoing  hypothesis  not  only  explains  the  apparent 
uniqueness  of  the  nausea  experience  (a  factitious  uniqueness, 
acquired  by  the  failure  of  the  observers  to  observe  sensory 
quality),  but  also  avoids  the  implication  that  a  unique  ex- 
perience must  have  a  unique  qualitative  basis.  The  positive 
reduction  of  nausea  to  organic  pressure  and  pain  is  not, 
however,  an  easy  task.  The  whole  pattern  is  so  complex, 
the  unity  of  the  situation  is  so  insistent,  the  fusion  of  the  ele- 
ments appears  in  consequence  so  intimate,  that  analysis  is 
difficult.  B  observed  that  attention  to  some  parts  seemed  to 
destroy  the  whole,  and  Y  declared  that  the  complex  as  a 
whole,  intimately  fused,  constituted  nausea.  A,  as  a  matter 
of  fact,  was  not  always  able  to  make  the  analysis.  He  could 
find  nothing  but  organic  sensation  of  pressure-like  quality, 
but  he  was  not  sure  that  there  was  not  something  else,  'a 
sickening  sensation,  a  kind  of  an  awfulness  and  helplessness.' 
When  asked  to  describe,  he  was  unable  to  do  more  than  to 
assume  the  'helpless  attitude'  (see  p.  319).  In  view  of  the 
fact  that  all  the  other  observers  made  the  analysis,  the  ina- 
bility of  A  to  reduce  the  complex  does  not  seem  to  warrant 
the  assumption  that  it  involved  a  new  element.  In  a  more 
general  context,  Titchener  has  remarked  that  the  impossi- 
bility of  reduction  in  a  single  case  need  not  imply  elementari- 
ness  if  the  analysis  can  be  made  by  other  individuals  or  in 
other  instances;1  and  it  appears  as  if  we  had  here  chanced 
upon  an  attitude  so  intimately  fused  that  its  reduction  was, 
under  our  conditions,  not  always  attainable.  It  should  be 
remembered,  too,  that  ^himself  was  not  sure  that  the  unique 
residuum  was  not  the  '  meaning  of  the  smell.' 

1  Titchener,  E.  B.,  'Experimental  Psychology  of  the  Thought  Processes,'  1909,  171. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     323 

THE  CALL  TO  DEFECATION 

Descriptions  of  the  call  to  defecation  and  of  the  act  itself 
were  written  down  by  the  observers  at  the  time  of  occurrence. 

Observer  A. — "Slight  strains  and  dull  pressures  of  weak  intensity  in  abdomen  are 
all  that  I  can  find  as  sensations." 

Observer  C. — "The  call  to  defecation  is  a  wave  of  pressure  of  quite  general  dis- 
tribution and  not  easily  localized.  It  is  somewhere  in  the  lower  abdominal  cavity  and 
finally  reaches  the  rectum.  When  this  wave  has  run  its  course  there  sets  in  a  general 
pressure  which  includes  the  whole  abdominal  contents.  At  high  intensities  the  mus- 
cular contractions  of  the  abdominal  wall  and  of  the  sphincter  are  added  to  the  former 
complex.  These  sensations  are  just  those  of  normal  contracting  muscle." 

Observer  D. — "Insistent  pressures  in  rectum.  Faint  but  slightly  achy  pressure  in 
front  wall  of  abdomen.  Slight  achy  pressure  in  temples,  which  feels  as  if  blood-vessels 
were  distended." 

Observer  E. — "The  call  to  defecation  is  a  very  pleasant  experience.  It  seems  to 
consist  of  a  feeling  of  fullness,  of  distension  of  the  bowels.  Pressure,  which  is  most 
prominent,  is  at  first  rather  indefinite  and  equal  in  all  directions,  but  later  becomes  a 
downward  one.  Sometimes  aches  and  pains  in  the  intestine  accompany  it." 

Observer  F. — "At  first,  vague,  diffuse  pressure  in  lower  abdomen,  not  particularly 
unpleasant.  Soon,  however,  it  becomes  a  dull  ache  and  often  sharply  painful.  There 
also  comes  an  ache  about  the  anus,  which  often  becomes  'hot'  and  'burny ';  and  this  is 
accompanied  by  violent  contractions  of  the  sphincter  muscle." 

Observer  X. — "  First  noted  impulse  to  go  to  toilet.  The  observed  vague  sensations 
localized  in  region  of  large  intestine,  a  vague  perception  of  movement  in  that  part  of 
the  intestinal  tract,  like  a  very  remote  dull  pressure  that  changed  its  location.  Also, 
sensations  of  incipient  movement  in  anus;  a  somewhat  rhythmic  movement  of  disten- 
sion abruptly  checked  each  time  by  movements  of  contraction.  All  this  was  quite 
involuntary.  The  internal  movement  (intermittent)  renewed  itself  more  intensely,  but 
just  as  vaguely;  the  localization  of  it  was  far  from  definite.  The  relaxation-phase  of 
the  anal  movement  tended  to  increase  in  duration  and  intensity.  After  a  time  the 
checking,  contracting  movement  ceased  to  occur  involuntarily.  Now  there  was  a 
definite  sensation  complex,  meaning  pressure  against  the  anal  opening  from  within  and 
above." 

Observer  Y. — "Intense  deep  pressure,  probably  muscular,  located  in  region  of 
anus.  Soreness  (of  the  pain  modality)  fused  with  the  pressure.  The  complex  was 
unpleasant." 

Observer  Z. — "Dull,  diffuse,  rather  heavy  pressure,  localized  rather  vaguely  in 
lower  abdomen.  Neither  pleasant  nor  unpleasant." 

In  experiments  described  elsewhere,  the  writer  has  shown 
that  the  call  to  defecation  may  be  induced  in  all  degrees  of 
intensity  by  the  inflation  of  a  rubber  bladder  within  the 
rectum;  that  small  amounts  of  warm  water  (50  c.c.,  50—70°  C.) 
produced  the  call  very  intensely  (although  an  equal  amount  of 
cold  water  at  o°  C.  did  not) ;  and  that  HC1  (10  c.c.,  5  per  cent.) 


324  E.  G.  BORING 

may  also  constitute  an  adequate  stimulus  to  the  call.1  The 
description  already  printed  calls  attention  to  the  specific 
sensation  of  muscular  pressure  in  the  rectum  (a  muscular 
'ache'  in  intense  degrees);  to  the  widespread  general  ab- 
dominal response,  apparently  secondary  and  dependent  upon 
muscular  contraction;  and  to  the  pains,  which,  when  the  call 
is  most  intense,  occur  in  great  variety  of  quality  and  reference. 
A  few  quotations  will  render  the  reference  explicit: 

Observer  B. — After  the  inflation  of  a  bladder  in  the  rectum  10  cm.  above  the  anus: 
"  First  pressure  in  rectum.  Then  call  to  defecation,  which  differs  from  the  first  pressure 
in  that  it  is  more  intense,  covers  a  larger  area,  and  has  a  temporal  course  of  varying 
intensity  (pulsations).  Later  pain  was  introduced.  From  then  on  intensity  increased 
by  jumps.  The  increase  of  pain  was  the  most  noticeable.  The  pain  was  of  the  achy 
variety,  but  got  sharper  and  brighter,  more  definite  and  lively,  although  always  diffuse, 
as  the  intensity  increased.  I  think  the  pressure  also  increased  in  intensity,  although  it 
was  largely  obscured  by  the  pain.  Vague  general  pressures  in  abdomen  were  also 
noticeable.  Still  later  pain  was  very  intense;  it  was  really  very  sharp  and  tended  to 
run  off  into  shoots  and  stings  of  pain.  The  temporal  course  up  to  this  point  shows,  I 
think,  all  degrees  of  urgency  for  defecation.  The  urgency  is  not  only  a  matter  of 
intensity,  but  varies  with  the  area  affected  and  also  with  the  quality  of  pain.  .  .  .  On 
the  release  of  the  pressure  there  is  a  tremendous  relief,  very  definite  in  the  region  of 
the  umbilicus  and  in  the  rectum.  It  is  exactly  like  the  relief  of  defecation  without 
the  sensations  of  passage.  It  is  kinesthetic  pressure." 

After  the  introduction  of  warm  water  into  the  rectum:  "Violent  call  to  defecation 
includes  pains  and  partially  initiated  movements  at  rectum.  More  or  less  confined  to 
rectal  region.  General  muscular  effort  in  resisting  call,  even  to  the  circulatory  warmth 
of  the  face.  Call  is  predominantly  a  pressury  ache  overshot  with  more  intense  thick 
pains  of  the  achy  variety.  Besides  this  there  is  a  general  muscular  irradiation."  In 
another  trial:  "  Intense  grippy  pains  about  umbilicus.  They  also  shoot  down  intotestes 
and  penis.  The  abdominal  pain  has  the  peculiar  character  of  'belly  ache.'  There  are 
also  pains  in  the  rectal  region,  such  as  occur  when  it  is  hard  to  hold  in  with  an  urgent 
call."  At  another  time  'shivers  over  whole  body*  are  noted. 

After  the  introduction  of  dilute  HC1:  "Sets  up  the  pressure  complexes  of  the  call 
to  defecation  in  rectum  at  once;  very  intense.  There  is  in  the  call  also  a  dull  ache;  but 
I  should  not  say  that  its  unpleasantness  is  dependent  upon  the  intensity  of  the  pain." 

The  call  to  defecation  is  predominantly  abdominal  pres- 
sure. The  pressure  may  mean  distension  or  contraction  or 
movement  or  effort;  it  may  be  weak  or  intense;  it  may  be 
dull,  diffuse,  and  vaguely  localized  or  it  may  be  clear-cut  and 
accompanied  by  a  definite  visual  reference.  Of  the  nine 

1  Op.  cit.,  5°~54-  Hertz's  observations,  op.  cit.,  28  ff.,  have  shown  that  the  call 
produced  by  inflation  of  a  bladder  arises  in  the  lower  rectum.  His  descriptions  do 
not  indicate,  however,  the  widespread  nature  of  the  response  nor  its  painful  character 
in  high  degrees. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     Z25 

observers  five  (#,  Z),  E,  F,  Y)  find  that  the  experience  in- 
volves aches  or  pains;  two  of  these  (Z?,  F)  also  find  'sharp 
pains/  Besides  the  general  abdominal  complexes,  definite 
rectal  pressures  are  mentioned  by  Z?,  Z),  X,  and  Y.  B  notes 
that  the  rectal  pressures  involve  the  ache  of  extreme  muscular 
pressure.  Two  observers  (B,  Y)  mention  that  the  call  is 
unpleasant,  two  (E,  Z)  that  it  is  indifferent,  one  (D)  that  it  is 
pleasant. 

IPs  fuller  introspections  for  the  intense  call  indicate  that 
the  course  for  increasing  intensity  is  more  or  less  as  follows: 
(i)  muscular  pressure  in  rectum;  (2)  rectal  pressure  becomes 
intense  and  achy,  general  abdominal  pressures  develop; 
(3)  dull  pain  introduced;  (4)  sharp,  piercing  pains,  of  uncertain 
and  varying  reference,  appear.  There  is  no  indication  of  the 
presence  of  qualities  not  ordinarily  included  in  the  pressure- 
pain  group. 

DEFECATION 

Reports  relating  to  the  experience  of  defecation  itself  are 
as  follows: 

Observer  A. — "Dull  pressures  in  abdomen;  increased  strain  in" abdominal  muscles. 
Pressure  in  rectum,  localized  two  or  three  inches  above  anus.  Sensations  of  cutaneous 
pressure  and  of  strain  as  feces  pass.  Slight  sweat." 

Observer  C. — "At  the  act  of  defecation  [following  the  call  to  defecation]  there  is  no 
new  quality  in  the  abdomen,  unless  the  diminishing  pressure  due  to  decreased  volume 
might  be  considered  as  such.  In  the  rectum  and  at  the  anus,  however,  the  moving 
contents  may  be  felt  as  waves  of  pressure.  .  .  .  The  only  quality  that  I  can  find  is  just 
pressure,  except  at  times  pain,  which  does  not  seem  to  be  normal." 

Observer  D. — "Increase  of  pressure  throughout  abdomen  and  especially  in  rectum. 
Bright  stingy  pressure  at  anus,  which  is  pleasant  and  which  carries  the  meaning  of 
expulsion." 

Observer  E. — "Defecation  itself  is  pleasant.  In  it  a  feeling  of  relaxation  and  a 
pressure,  bearing  down,  are  mixed." 

Observer  F. — "First  the  sensations  of  relaxation  of  the  sphincter  and  abdominal 
muscles;  then  those  of  the  moving  pressure  at  expulsion." 

Observer  X. — "Movement  of  issuing  feces  somewhat  perceived  somewhere  in  the 
large  intestine  (as  vaguely  dull,  indefinite,  moving  pressure,  rather  rhythmic  in  its 
fluctuations  of  intensity),  but  chiefly  precisely  at  the  anal  opening.  Here  there  was  a 
definite  clear-cut  experience:  very  strong,  bright,  'moving'  contact  and  large  pressure 
sensations;  occasional  pain  elements,  sharp  and  bright.  Slightly  shivery  sensations 
ran  up  spine,  and  to  some  extent  seemed  to  well  out  from  the  anal  region.  Felt  'goose- 
fleshy.'  "  At  another  time:  "Noted  that  preliminary  internal  sensations  were  stronger, 
more  definite  and  steadier.  They  included  dull,  diffuse,  deep  pressure  with  a  vague, 
weak  subcurrent  of  dull  pain.  Occasionally  there  were  sharp,  knife-like  streaks  of 
pain." 


326  E.  G.  BORING 

Observer  Y. — "Defecation-complex  is  made  up  of  the  following  factors:  muscular 
sensations  in  anus;  soreness,  which  was  more  distinctly  painful  in  character,  and  which 
varied  in  intensity  during  defecation;  and,  I  think,  another  kind  of  pressure,  located 
at  the  distal  end  of  the  anus  and  meaning  contact  of  waste-products  with  that  part. 
There  was  also  present  a  feeling  of  general  strain." 

Observer  Z. — "Contraction  of  many  muscles  of  abdomen  with  resulting  strain 
sensations.  More  intense  muscular  sensations  localized  in  rectum;  pressure  localized 
vaguely  in  the  same  place.  During  and  after  the  contraction  of  the  muscles,  a  pain  of 
a  moving  pressure." 

As  defecation  follows  the  call,  the  abdominal  contractions 
that  induce  it  are  sensed  as  strain  (A,  Y,  Z)  or  as  pressure 
(D,  X).  The  dull  rectal  pressure  increases  in  denniteness 
and  intensity  and  ordinarily  becomes  painful  (C,  -D,  X,  Y,  Z). 
This  pain  may  be  a  dull  ache  or  soreness  (X,  Y)  or  it  may  be 
bright,  stingy,  sharp,  and  knife-like  (D,  X,  Z).  D  and  E 
describe  the  experience  as  pleasant,  D  specifying  that  it  is 
the  ' stingy  pressure'  which  is  pleasant.  This  introspection 
agrees  with  that  of  the  writer.  In  general,  it  may  be  said 
that  the  experience  of  defecation  is  little  more  than  a  height- 
ening of  the  call  to  defecation,  with  a  consequent  introduction 
of  algesic  elements,  and  with  perceptual  additions  relating 
to  the  passage  of  the  feces. 

THE  CALL  TO  URINATION 

The  descriptions  of  urination  and  of  the  call  to  urination 
were  obtained  in  the  same  manner  as  those  of  defecation. 

Observer  A. — "Weak  sensations,  very  much  like  muscular  pressure,  spread  over  an 
area  high  inside  of  body  with  base  just  above  the  pubic  bone.  Later  these  sensations 
became  slightly  stronger  in  intensity  and  seemed  more  strainy  in  quality,  although  they 
were  still  of  weak  absolute  intensity.  In  the  penis,  especially  the  lower  part  (urethra), 
there  were  very  weak  sensations  like  contact  and  very  weak  cutaneous  pain  combined. 
Also  a  cool  sensation  in  the  glans  near  the  opening.  Still  later  I  noticed  weak  strainy 
sensations  referred  to  the  penis  throughout  its  length  and  to  the  body.  The  sensations 
were  strongest  at  the  opening  of  the  urethra." 

Observer  B. — "Dull  pressure-ache,  like  that  of  intense  muscular  pressure,  referred 
generally  to  region  of  penis,  scrotum,  and  pubes.  Localization  not  specific,  for  complex 
appears  big  and  round,  and  attention  to  any  particular  organ  makes  the  sensation  appear 
to  go  elsewhere  although  it  remains  in  the  same  general  region.  The  penis  is,  however, 
always  involved;  the  dull  ache  is  most  intense  there.  Dull  pressure  without  ache  centers 
in  the  pubic  region.  Besides  the  dull  ache  there  is  a  sharper  ache  referred  to  the  penis 
in  a  region  about  half-way  between  the  root  and  the  glans.  It  is  very  much  like  a 
'sting'  that  is  spread  out.  It  varies  quite  regularly  in  intensity,  intense  pulses  being 
separated  from  weak  ones  or  from  periods  in  which  there  is  no  ache  at  all.  [I  have  had 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     3  27 

an  assistant  note  the  time  of  these  fluctuations  for  5  min.  There  were  30  maxima 
in  this  time,  an  average  separation  of  10.1  +  3.6  sees.  Ten  times  the  pulsations  died 
out  entirely.  About  once  a  minute  there  is  a  long  interval,  which  serves  to  divide  the 
pulsations  into  groups.]  Ordinarily,  I  think,  attention  fluctuates,  returning  to  the  call 
when  this  sharp  ache  is  most  intense.  When  the  call  gets  strong,  there  are  muscular 
twitches — pressure  sensations — prominent.  Also  a  general  restlessness." 

Observer  C. — "The  call  in  its  initial  stages  is  intermittent  and  lapses  with  the 
application  of  attention.  When  it  really  becomes  insistent  it  is  very  unpleasant.  The 
components  seem  to  be  principally  strain  sensations  from  muscles  and  sensations  of 
warmth.  The  first  strain  seems  to  be  from  the  contractions  of  the  bladder,  at  least 
it  is  in  the  lower  abdominal  cavity.  It  is  a  wave,  moving  from  above  downwards.  At 
once  this  wave  is  met  by  a  wall  of  pressure,  and  the  two  opposing  strains  seem  to  see- 
saw. The  essential  thing  is  strain,  I  think  the  resisting  strain  comes  from  the  con- 
traction of  the  sphincter  muscles  at  the  origin  of  the  urethra.  From  this  point  lesser 
waves  of  pressure  occasionally  pass  outwards  to  the  distal  end  of  the  urethra.  In 
addition  to  this  pressure  there  is  a  sort  of  quality  much  like  the  pricking  of  a  stiff  hair 
applied  to  a  pain  or  pressure  spot  in  the  skin.  The  bladder  and  the  sphincter  strains 
spread  until  the  muscles  of  the  abdominal  wall  are  involved." 

Observer  D. — "The  call  to  urination  consists  principally  of  bright  stingy  pressures 
in  penis,  mostly  near  the  base.  There  is  also  a  slight  diffuse  pressure  higher  in  ab- 
domen, which  feels  like  the  pressure  of  a  filled  bladder." 

Observer  E. — "The  call  to  urination  is  a  very  pleasant  thing,  provided  it  be  not  too 
strong.  It  consists  of  a  feeling  of  distension,  of  outward  pressure." 

Observer  F. — "A  vague  indefinite  pressure  in  the  lower  abdomen,  rising  as  high  as 
the  umbilicus.  Intermittent  pain  in  the  glans  penis.  Whole  thing  uncomfortable." 

Observer  X. — "The  unintense  experience  of  normal  life  is  as  a  rule  scarcely  con- 
scious; there  seems  to  be  an  automatic  reaction  before  the  sensations  become  at  all 
intense.  .  .  .  The  experience,  when  intense,  includes  (i)  a  general  bodily  uneasiness, 
especially  in  the  lower  portion  of  abdomen;  (2)  a  definite  pain-complex,  localized  slightly 
below  the  middle  of  the  abdominal  cavity;  it  is  an  achy  pain  with  something  of  the 
strained  feeling  to  it;  it  is  insistent,  definite,  persistent;  (3)  a  vague  feeling  of  'repletion' 
of  the  abdominal  cavity — a  complex  made  up  chiefly  of  dull  pressures  with  perhaps  a 
slight  pain-component;  (4)  intermittent  sensations,  localized  at  the  opening  of  the 
urethra.  The  'general  uneasiness'  is  centered  upon  this  region,  and  the  attention  is 
drawn  strongly  to  very  bright  and  lively  kinesthetic  sensations  of  incipient  movement 
there." 

Observer  Y. — "Warmth;  and  a  sort  of  ticklish  pressure,  located  in  the  region  of 
the  urethra  and  the  bladder.  The  'ticklishness'  belongs  to  the  modality  of  pain. 
This  complex  is  set  in  a  general  muscular  feeling." 

Observer  Z. — "Very  slight  warmth.  Light  diffuse  pressure,  spreading  out  through 
a  comparatively  small  space  and  very  poorly  localized  in  the  lower  pelvic  region  toward 
the  front  of  the  body.  Affective  tone  was  indifferent." 

All  observers  describe  sensations  of  fullness  or  of  pressure 
or  of  strain  in  the  region  of  the  bladder.  X  and  Y  refer  an 
algesic  quality  to  this  region,  and  it  is  just  possible  that  the 
strain  noted  by  A  and  C  is  incipiently  algesic.  The  most 
prominent  part  of  the  call  for  the  male  observers  seems  to 


328  E.  G.  SORING 

be,  however,  a  pressure-pain  complex,  in  which  the  pain 
dominates,  and  which  is  referred  to  the  penis  (variously  to 
the  base,  the  side  in  which  the  urethra  lies,  a  point  between 
the  base  and  the  glans,  and  the  glans).  All  the  male  ob- 
servers (except  E,  whose  introspection  is  too  scanty  to  be 
considered  analytically)  report  pain.  A  finds  'weak  cutan- 
eous pain';  B,  besides  the  'dull  pressure-ache,'  a  'sharp, 
pulsating,  intermittent  pain';  C,  a  'pricking  pain';  Z),  a 
'stinging  pressure';  and  F,  an  'intermittent  pain.'  A^  B,  C, 
and  D  describe  the  pain  as  mingled  with  contact  and  strain, 
with  pressure  and  muscular  sensations,  or  with  pressure. 
The  reports  of  the  women  are  quite  similar.  X  notes  an 
ache  in  the  region  of  the  bladder,  and  Y  a  'ticklish'  pain. 
X  finds  bright  and  lively  kinesthesis  at  the  urethra.  For 
Z  the  experience  is  quite  colorless — merely  a  diffuse  pressure 
and  warmth. 

The  affective  judgments  vary  considerably.  B  finds  the 
pains  pleasant,  and  E  reports  that  the  whole  experience, 
when  weak,  is  very  pleasant.  Z  records  indifference,  and 
C  and  F  unpleasantness — at  least  when  the  call  is  intense. 

URINATION 

The  act  of  urination  is  described  as  follows: 

Observer  A. — "Voluntary  relaxation  of  the  strains  referred  to  the  urethral  opening, 
tactual  sensations  (like  those  from  mucous  membrane  of  mouth)  and,  at  the  very  first, 
very  weak  cutaneous  pain  sensations,  diffused  through  these  tactual  sensations,  or 
spotted,  peppered,  around  in  them.  These  sensations  are  referred  to  the  urethra, 
almost  for  the  entire  length  of  the  penis.  The  whole  experience  was  pleasant." 

Observer  B. — "Sharp  aches,  like  the  intermittent  ones  in  the  call  to  urination, 
become  very  intense  just  at  the  initiation  of  passage.  They  are  referred  to  the  same 
region  as  before,  i.  e.,  above  the  glans,  about  one  third  of  the  way  to  the  base.  The 
aches  get  weak  as  passage  starts  and  continue  so  until  the  end.  Then,  as  the  last  dribble 
passes,  they  become  momentarily  intense  again.  After  that  they  weaken  and  die  out 
slowly  during  the  subsequent  minute.  There  are  dull  muscular  sensations  in  the  region 
of  the  bladder,  which  are  not  at  all  prominent.  The  relief  afterwards  is  represented 
by  the  persistent  aches  in  the  penis,  as  described,  and  a  large  diffuse  ache  of  the  same 
quality  in  the  region  of  the  bladder.  .  .  .  All  these  sharp  aches  are  very  pleasant  indeed. 
Even  when  one  is  restraining  urination  with  much  effort,  the  pulsations  of  pain  are 
very  pleasant.  They  are,  I  think,  similar  to,  if  not  identical  with,  the  sensations  of  the 
sexual  organs  at  a  low  degree."1 

1  The  completion  of  urination  is  physiologically  similar  to  ejaculation.  The  last 
portions  of  urine  are  expelled  by  rhythmical  contractions  of  the  bulbocavernosus  muscle. 
See  Howell,  op.  cit.,  785,  898. 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS     329 

Observer  C. — "Strain  in  the  muscles  of  expulsion  but  relaxation  in  the  sphincter 
muscles.  In  the  urethra  there  is  a  warm  pressure,  which  persists  just  for  a  moment 
after  the  act  is  over.  General  relaxation  marks  the  closing." 

Observer  D. — "At  the  beginning  the  pressure  in  the  penis  gives  way  to  a  tingling. 
This  changes  to  a  complex  which  I  have  not  been  able  to  analyse,  but  which  means 
liquid  flowing  through  the  urethra.  There  is  also  general  relief  of  pressure  in  the 
bladder." 

Observer  E. — "Pleasant,  but  I  have  not  been  able  to  reduce  the  experience  to 
words." 

Observer  F. — "At  first  there  is  a  sharp  burning  pain  in  the  glans  penis.  Then 
nothing  but  the  pressures  accompanying  the  flow  of  urine.  At  the  end  there  is  a 
repetition  of  the  beginning  pain,  only  it  is  much  stronger." 

Observer  X. — "Urination  is  accompanied  by  almost  no  sensations.  There  is  a 
lack  of  the  strain  sensations  experienced  in  trying  to  hold  back  the  reaction, — a  general 
bodily  relaxation.  There  are  very  weak,  bright,  contact  sensations  at  the  opening. 
The  pain  sensations  [described  in  the  call  in  the  region  of  the  bladder]  do  not  change  in 
intensity  or  cease  until  some  time  after  the  operation  is  completed." 

Observer  Y. — "Muscular  sensations  in  region  of  the  urethra  and  bladder.  Warm- 
pressure  perception  (flowing  of  liquid)  and  auditory  perception  (liquid  striking  water). 
This  perceptual  complex,  set  in  a  weak,  general  tension,  present  during  urination. 
Afterwards  a  general  feeling  of  relaxation,  slightly  pleasant." 

Observer  Z. — "Almost  sensationless.  Very  weak  pressure  sensations,  moving  in 
scarcely  perceptible  waves, — just  like  the  faintly  discriminable  changes  in  pressure 
you  get  from  floating  when  in  swimming.  With  these  pressures,  very  weak  muscular 
feeling  of  relaxed  muscles  all  over  and  through  the  abdomen." 

There  has  recently  been  reported  to  the  writer  a  case  of  a  woman  who  was  unable 
on  a  railroad  train  to  tell  whether  she  was  urinating  or  not.  The  noise  of  the  train  so 
obscured  the  usual  auditory  cues,  she  said,  that  she  could  not  make  the  judgment. 
No  doubt  the  jar  of  the  train  prevented  any  faint  organic  sensations,  which  may  have 
been  present,  from  being  distinguished  as  cues. 

Like  the  call  to  urination,  in  the  men  urination  proper 
involves  principally  a  pressure-pain  complex  in  the  penis. 
Some  mention  is  made  of  muscular  or  strain  sensations  in 
abdominal  regions,  but  the  characteristic  experience  seems 
to  be  referred  to  the  penis,  and  is  caused,  no  doubt,  by  the 
distension  of  the  urethra.  Distention  here,  as  elsewhere, 
may  be  expected  to  result  in  pain.  The  less  experienced 
observers  had  difficulty  in  making  the  analysis.  The  others 
find  in  some  cases  tactual  sensations,  strains,  or  the  less 
definite  '  pressure.'  Pain  is  possibly  universal.  A  finds 
'cutaneous  pain,'  $,  ' sharp  aches';  F,  ' sharp,  burning  pain.' 
The  'tingling'  of  D  implies  pain,  and,  when  one  is  familiar 
with  the  usual  stinging  response  of  the  penis  to  warm  stimu- 
lation, one  is  tempted  to  read  an  algesic  quality  into  C's 
'warm  pressure.' 


33°  E>  G.  BORING 

In  the  women  the  experience  seems  to  be  as  indefinite  and 
colorless  as  it  is  striking  in  the  men.  X  and  Z  call  it  'almost 
sensationless,'  and  they  are  supported  by  the  case  last  cited. 
Muscular  sensations  and  weak  contacts  and  pressures  are 
noted  in  the  effort  to  find  something  to  report.  A  true  sex 
difference  seems  to  exist. 

The  experience  is  doubtless  affectively  indifferent  for  the 
women.  Of  the  men,  three  (A,  B,  E)  mention  the  affective 
aspect  and  all  declare  that  it  is  definitely  pleasant. 

CONCLUSION 

We  may  conclude  that  thirst,  hunger,  nausea,  the  call  to 
defecation,  defecation,  the  call  to  urination,  and  urination 
are  all  complex  experiences  reducible,  under  favorable  con- 
ditions, to  various  patterns  of  pressure  and  pain. 

The  experiences  may  be  very  complex  and  may  vary  from 
individual  to  individual.  Nausea  is,  perhaps,  the  extreme 
example.  Different  processes  may  stand  for  it  at  different 
times;  and  again,  it  may  become  so  attitudinal  as  to  defy 
analysis.  Hunger  is  reduced  to  a  single  pain  only  by  isolating 
it  from  appetite.  Thirst  is  confined  to  the  mouth  and  throat, 
frequently  to  the  mouth  only,  but  is  definitely  of  the  per- 
ceptual order.  The  excretory  complexes  are  less  frequently 
recognized  as  specific,  and  show  a  correspondingly  wide 
variation  in  their  many  constituents. 

The  reduction  to  pressure  and  pain  suggests  the  possibility 
of  a  number  of  qualities  within  each  of  those  modalities. 
Besides  occasional  pressure  of  cutaneous  quality,  dull  pressure 
and  muscular  pressure  were  the  most  frequent  forms  reported. 
As  is  usual,  the  muscular  pressure  in  intense  degrees  runs  off 
into  painful  ache.  There  were  also  sharp  pains  which,  it 
may  be,  are  of  more  than  one  kind. 

Pain,  although  less  usual  than  pressure,  is  by  no  means 
uncommon.  It  may  be  present  in  the  throat  in  thirst;  hunger 
is  pain;  the  most  constant  constituent  of  nausea  is  the  same 
pain  as  that  of  hunger;  the  call  to  defecation,  when  intense, 
involves  sharp,  shooting  pains  and  dull  aches;  defecation 
may  include  stinging  sensations  at  the  anus;  urination  and 


PROCESSES  REFERRED  TO  ALIMENTARY  AND  URINARY  TRACTS    33 l 

the  call  involve  aches  in  the  region  of  the  bladder  and,  in 
the  male,  bright  pain  in  the  penis.  These  pains  may  be 
accompanied  by  any  affective  judgments  whatever.  The 
intense  bright  pain  of  urination  may  be  very  pleasant,  while 
that  in  the  call  to  defecation  may  be  extremely  unpleasant. 
The  present  paper  has  been  mainly  analytical.  The 
problem  that  it  attacks  must  remain  unsolved  until  the  com- 
plementary synthetic  operation  has  been  performed.  It  is 
one  thing  to  reduce  a  large  part  of  organic  experience  to 
pressure  and  pain;  it  is  another  thing  to  say  how  many 
pressures  and  how  many  pains  there  are,  how  they  differ 
from  one  another,  and  how  they  combine  to  form  the  typical 
complex  processes  of  organic  life.  This  second  phase  of  the 
problem  it  is  the  writer's  hope  to  bring  into  the  laboratory. 


VOL.  XXII.  No.  5  September,  1915 


THE  PSYCHOLOGICAL  REVIEW 


THE  FATHER  OF  MODERN  PSYCHOLOGY 

BY  PROFESSOR  FOSTER  WATSON 

The  *  father'  of  modern  psychology  was,  I  suggest,  Juan 
Luis  Vives.  It  may  be  objected  that  if  we  take  l modern'  in 
a  sufficiently  literal  sense,  we  must  go  back  to  Aristotle. 
For  that  great  philosopher  traced  the  origin  and  development 
of  the  pre-Socratic  psychology,  critically  examined  the 
Platonic  views,  embodied  and  organized  from  his  predecessors 
whatever  would  serve  as  basis;  and  for  the  rest,  supplied, 
from  his  own  researches  and  thought,  an  organic  system  of 
psychology,  which  has  held  its  own,  and  still  claims  close 
study — from  the  fourth  century  B.C.  to  the  present  time — 
continuously  for  over  twenty-two  centuries  and  a  half.  St. 
Thomas  Aquinas,  fifteen  hundred  years  after  Aristotle, 
re-affirmed  the  main  points  of  Aristotelian  psychology,  but 
supplemented  them  by  a  rationalized  interpretation,  in  which 
he,  in  many  cases,  anticipated  modern  psychological  thought.1 

Doubtless  the  line  of  continuity  in  psychological  advance 
is  traceable,  in  this  way,  to  Aristotle  as  the  real  founder  of 
the  subject.  But,  our  modern  division  of  history,  into 
ancient,  mediaeval  and  modern,  requires  us  to  consider  new 
starting-points,  though,  logically,  in  the  light  of  the  principle 
of  continuity,  it  is  misleading  to  regard  even  these  great 
divisions  as  abrupt  transitions.  Although  the  Renascence 
period  of  the  fifteenth  and  sixteenth  centuries  brought  a 
steady  concentration  of  attention  upon  psychological  ques- 
tions, as  it  did  upon  all  humanistic  problems,  yet  the  main 

1  The  Rev.  Prof.  Michael  Maher,  S.  J.,  has  shown  in  his  interesting  'Psychology — 
Empirical  and  Rational'  the  parallels  between  St.  Thomas  Aquinas  and  modern  psy- 
chology. 

333 


334  FOSTER  WATSON 

setting  of  psychological  theory  had  clearly  been  determined 
by  those  great  thinkers,  Aristotle  and  St.  Thomas  Aquinas; 
and  any  advance  was  most  hopefully  to  be  looked  for,  which 
started  from  them  as  basis. 

It  is  often  stated  that  'the  father'  of  modern  psychology 
was  Rene  Descartes  (1596-1650).  Without  attempting  to 
withdraw  any  credit  from  the  actual  accomplishments  of 
Descartes,  in  his  day  and  generation,  in  the  subject  of  psy- 
chology, it  would  be  extraordinary,  on  a  priori  grounds,  if  the 
period  of  the  Renascence  (say  from  1450  onwards)  till  the 
time  of  the  birth  of  Descartes  (1596)  had  failed  to  produce  a 
conspicuous  thinker  on  a  subject  so  essentially  humanistic, 
as  that  of  the  Mind.  Some  writers,  accordingly,  place  Francis 
Bacon  (1561-1626)  as  the  pioneer  of  modern  psychology. 
Bacon  was,  certainly,  the  most  influential  advocate  of  the  em- 
pirical scientific  method  of  the  seventeenth  century.  Psy- 
chology has  made  its  great  advance  by  the  employment  of 
this  method.  Hence,  it  is  urged,  Bacon  is  the  leader  to  whom 
modern  psychology  traces  its  beginning.  But  neither  Bacon 
nor  Descartes  was  the  first  Renascence  writer  to  give  his 
attention  to  psychological  theory,  nor  even  to  the  advocacy 
of  the  empirical  inductive  method.  In  a  wide  though  valid 
sense  of  the  term,  every  man  is  a  psychologist,  and  every  man 
employs  the  inductive  method,  and  the  'fatherhood'  of  both 
goes  back  to  an  antiquity,  not  merely  as  old  as  Aristotle,  but 
as  old  as  man  himself,  at  least.  But  the  self-conscious  em- 
phasis on  induction  as  a  method  of  inquiry  and  discovery  in 
philosophical,  and  particularly  in  psychological  questions, 
must  be  taken  back,  even  in  Renascence  times,  beyond  and 
before  Descartes  and  Bacon,  at  any  rate,  to  Juan  Luis  Vives 
(1492-1540). 

Thus,  Vives  shows  explicitly  his  insight  into  the  signifi- 
cance of  the  empirical  inductive  method  in  his  account  of  the 
origin  of  the  arts.  For  the  formulation  of  the  arts,  says  Vives, 
was  due  to  observation  joined  with  reasoning.  "In  the 
beginning,  first  one,  then  another  experience,  through  wonder 
at  its  novelty,  was  noted  down  for  use  in  life;  from  a  number 
of  separate  experiments  the  mind  gathered  a  universal  law, 


THE  FATHER  OF  MODERN  PSYCHOLOGY  335 

which,  after  support  and  confirmation  by  many  experiments 
was  considered  certain  and  established.  Then  this  knowledge 
was  handed  down  to  posterity.  Others  added  subject-matter 
which  tended  to  the  same  use  and  end.  This  collection  of 
knowledge-material  by  men  of  great  and  distinguished  intel- 
lect, constituted  the  several  branches  of  knowledge,  or  the 
arts.  .  .  .  Whatever  is  in  the  arts  was  in  nature  first,  just  as 
pearls  are  in  shells,  or  gems  in  the  sand."1  The  insight  which 
Vives  brought  to  bear  on  the  place  of  the  empirical,  inductive 
method,  in  the  building  up  of  the  arts  and  sciences,  was  of  the 
first  importance  to  him,  when  he  came  to  study  the  subject 
of  psychology,  theoretically. 

In  1538,  Vives  published  his  book  on  psychology,  entitled, 
after  the  work  of  Aristotle:  'De  Anima  et  Vita.'  He  ad- 
dressed it  to  Francis,  duke  of  Bejar,  to  whose  descendant, 
another  duke  of  Bejar,  Cervantes  in  1605  dedicated  'El 
Ingenioso  Hidalgo  Don  Quijote  de  la  Mancha.' 

In  this  Preface  to  the  'De  Anima,'  Vives  makes  clear  that 
he  writes  on  the  mind,  in  no  perfunctory  or  merely  conven- 
tional spirit,  for  he  recognizes  that  the  knowledge  of  the  mind 
has  relation  to  matters  'of  the  greatest  usefulness'  To  govern 
oneself  one  must  know  onself,  not  only  as  so  much  bones  and 
flesh  and  nerves  and  blood  (though  these  come  into  the 
calculation)  but  each  should  learn  to  observe  the  nature, 
quality,  ability,  strength,  passions,  of  the  mind.  Each  should 
'explore'  himself  in  his  varied  nooks,  and  even  obscurities  of 
mental  life.  "On  this  account,  it  seemed  good  to  me  to 
ponder  deeply  on  some  points  of  this  great  subject,  all  the 
more  because  recent  philosophers  have  brought  but  little 
industry  to  the  study,  content  with  what  had  been  left  behind 
by  the  ancients.  They  have  added  nothing  at  all  except 
problems,  almost  impossible  of  solution,  and  such  that,  even 
if  solved,  would  bring  no  fruitfulness.  Formerly  the  ancients 
involved  themselves  in  great  absurdities  on  this  subject,  for 
they  thought  wrongly  of  the  mind,  which  is  not  perceived  by 

1  For  an  account  of  the  relation  between  Francis  Bacon  and  Juan  Luis  Vives  see 
Rudolf  Gunther,  'Inwieweit  hat  Ludwig  Vives  die  Ideen  Bacos  von  Verulam  vor- 
bereitet'  (1912),  and  as  to  the  influence  of  Vives  on  Descartes  see,  Roman  Fade, 
'Die  Affectenlehre  des  Johannes  Ludovicus  Vives'  (1893). 


336  FOSTER  WATSON 

the  bodily  senses — and  even  their  opinions  on  the  very  matters 
which  we  do  perceive  by  the  senses  were  most  inept." 

Vives  deliberately  passes  by  the  method  then, — as  ever — so 
much  in  vogue  of  rebutting  opinions  deemed  to  be  false,  which 
he  says  are  more  numerous  in  this  than  in  any  other  subject  of 
inquiry.  Such  refutations  would  lead  to  thorns  rather  than 
fruit.1  He  will  attempt  to  fit  into  the  structure  of  his  dis- 
course, '  those  expressions  which  have  sprung  from  the  people 
and  are'in  common  acceptance  with  them,  and'then  have  become 
unintelligible  as  they  have  passed  into  the  use  of  the  learned.' 
For  in  dealing  with  the  recondite  problems  of  the  mind,  the 
adaptation  of  a  fitting  vocabulary  is  a  serious  part  of  the  under- 
taking if  a  treatise  is  to  be  accommodated  to  learners.  Vives's 
•concern  for  his  choice  of  language  and  vocabulary,  it  will  be 
remembered,  was  reflected,  with  such  good  consequences, 
in  his  successors  Francis  Bacon,  Thomas  Hobbes,  and  Rene 
Descartes,  and  very  specially  in  John  Locke's  'Essay  on  the 
Human  Understanding,'  Book  III.,  than  which  it  would  be 
difficult  to  find  a  more  masterly  exposition  of  language  as 
the  means  of  expressing  ideas  clearly. 

In  his  address  to  the  duke  of  Bejar,  then,  Vives  claims 
that  he  has  parted  company  with  the  mischievous  babblings 
of  the  Stoics  and  their  carping  sophisms,  and  no  less  with  the 
hidden  and  subtle  opinions  of  Aristotle. 

In  describing  the  contents  of  Vives's  'De  Anima'  it  will  be 
more  profitable  to  emphasize  his  independent  and  original 
^views  rather  than  to  dwell  upon  the  undoubtedly  many 
points  of  similarity  which  could  be  found  in  his  book  with  the 
.subject-matter  in  the  works  of  Aristotle  and  St.  Thomas 
Aquinas.2 

Tired  of  the  atmosphere  of  dialectical  displays  which 
inflated  the  pride  of  victory  rather  than  stimulated  the 
search  for  truth,  Vives  was  ready  to  try  new  paths.  The  time- 
honored  treatment  of  psychology  included  a  discussion  of  the 

1  Vives,  however,  to  some  extent,  deals  with  the  'false  opinions'  of  his  predecessors 
"in  psychology,  in  his  'De  Causis  Corruptarum  Artium'  and  in  his  'De  Veritate  Fidei 

Christianae.' 

2  See  T.  G.  A.  Kater,  'J.  L.  Vives  und  seine  Stellung  zu  Aristoteles;'  G.  Hoppe, 
^Die  Psychologic  des  J.  L.  Vives;'  R.  Fade,  'Die  Affectenlehre  des  J.  L.  Vives.' 


THE  FATHER  OF  MODERN  PSYCHOLOGY  337 

question  What  is  the  soul?  Yet  Vives  ventures  to  write  a 
book  entitled  'De  Anima'  in  which  he  says:  "What  the  soul 
is,  is  of  no  concern  for  us  to  know;  what  it  is  like,  what  its 
manifestations  are,  is  of  very  great  importance."1  This  calm 
renunciation  of  the  metaphysical  aspect  in  favor  of  the  de- 
scriptive account  of  the  activities  of  the  mind  is  a  natural 
enough  result  from  Vives's  revolt  from  the  older  academic 
disputational  methods,  which  precluded  progress,  because 
they  could  not  reach  further  in  their  conclusions  than  they 
assumed  in  their  premises,  and  their  premises  were  always 
ultimately  founded  on  a  priori  abstractions.  Thus,  disputes 
on  the  nature  of  the  soul  either  began  in  the  unknown,  and 
ended  there,  or  else  sought  an  authoritative  basis,  which 
was  similarly  substantially  unknown  (because  not  subjected  to 
enquiry).  Vives,  therefore,  excluded  the  discussion  of  what 
the  soul  is,  in  its  essence,  from  his  scope.  Instead,  he  asks 
for  careful  investigation  into  the  manifestations  of  the  soul 
in  all  the  activities  of  consciousness.  "We  cannot  rightly 
declare  what  the  soul  is  in  its  essence,  and  as  a  bare  thing 
place  it,  as  it  were,  before  the  eyes,  but  we  can  set  it  forth, 
clothed  and  as  if  painted  in  a  picture,  in  its  own  most  apt 
colors,  so  that  it  is  seen  in  its  own  actions.  For  it  has  not 
come  under  the  observation  of  our  senses,  but  we  perceive  its 
works  (opera}  by  almost  all  the  senses,  internal  and  external. 
Surely  the  goodness  of  the  Lord  of  Nature  to  us  reveals  itself 
by  many  proofs,  on  every  side,  by  thus  aiding  us,  in  placing 
before  our  eyes  and  in  such  abundance,  these  manifestations 
of  the  soul.  For  there  is  no  sign  more  clear  that  things 
are  not  to  be  converted  to  our  use  than  for  them  to  be 
remote,  rare,  difficult  to  be  prepared.  Nor  did  he  who  bid  us 
know  ourselves,  refer  to  the  essence,  but  to  the  actions  of 
our  mind  so  that  they  may  be  ordered  for  moral  life,  and  by 
the  expulsion  of  vice,  we  may  follow  virtue  which  will  so 
lead  us  that  we  may  spend  in  full  wisdom,  as  immortals,  the 
happiest  eternity."  It  is  a  central  doctrine  of  Vives  that 
Knowledge  is  of  value,  simply  when  it  is  'put  to  use.'  The 

1  Anima  quid  sit,  nihil  interest  nostra  scire,  qualis  autem,  et  quae  eius  opera,  per- 
multum.     'Opera,'  Vol.  III.,  p.  332. 


33$  FOSTER  WATSON 

observational  method  of  studying  the  manifestations  of  our 
minds  has  a  value  for  application  which  cannot  be  gainsaid. 
If  indeed,  the  processes  of  cognition  were  to  be  regarded  as 
only  of  intellectual  worth,  even  then  the  right  study  of  the 
passions,  as  they  show  themselves  in  ourselves  and  in  the 
individuals  we  read  of  in  history,  would  be  of  direct  ethical 
significance  for  the  purposes  of  examples  or  of  warnings. 
And,  accordingly,  Vives  devotes  one  of  the  three  books  of  the 
'De  Anima'  to  a  critical  and  constructive  study  of  the 
passions. 

We  have  seen  that  Vives  places  the  emphasis  in  psycho- 
logical studies  upon  the  observation  of  the  manifestations  of  the 
soul,  in  its  outward  realized  activities.  When  we  thus  observe 
the  results  of  mental  activity  in  the  numerous  forms  of  cogni- 
tion feeling,  will,  in  other  persons,  or  in  ourselves,  we  are  at  the 
point  of  view  of  empirical  psychology.  Vives  may,  therefore, 
be  claimed  as  a  pioneer  in  the  advocacy  of  this  method,  prior 
to  Francis  Bacon  and  to  Rene  Descartes.  It  was  not  a  long 
step  to  take,  to  advance  from  the  empirical  psychology,  which 
is  concerned  in  tracing  the  processes  of  mental  activity  in 
others  to  that  of  recording,  by  way  of  psychological  investi- 
gation, the  results  of  interrogation  as  to  what  has  happened 
in  one's  own  mental  experiences.  Hence,  illustrations  can 
be  found  in  Vives,  of  the  conscious  employment  of  the  intro- 
spective, empirical  method,  the  method  that  is  especially 
characteristic  of  later  psychological  students,  and  as  these 
appear  to  be  the  first  instances  of  conscious  introspective 
interrogation  of  consciousness  in  psychological  investigation 
in  modern  times,  i.  e.,  from  the  Renascence  onwards,  they  are 
of  more  than  ordinary  interest  and  significance. 

"As  often,"  says  Vives,  "as  I  see  a  house  at  Brussels, 
which  is  opposite  to  the  Royal  Palace,  Idiaqueus  comes  into 
my  mind,  for  he  is  its  occupier.  Very  often  in  that  house,as 
far  as  his  business  would  allow,  we  used  to  chat  over  matters 
pleasant  to  both  of  us.  Now,  as  often  as  I  revolve  the  idea 
of  Idiaqueus  I  do  not  think  of  the  Palace,  because  the  mem- 
ory of  my  friend  and  his  house  is  more  noteworthy  to  me  than 


THE  FATHER  OF  MODERN  PSYCHOLOGY  339 

the  idea  of  the  Royal  Palace.1  So  with  sounds,  tastes,  smells. 
When  I  was  a  boy  at  Valencia,  I  was  ill  of  a  fever.  Whilst 
my  taste  was  deranged,  I  ate  cherries.  For  many  years 
afterwards,  whenever  I  tasted  fruit  I  not  only  recalled  the 
fever,  but  also  seemed  to  experience  it  again."2 

These  illustrations  of  the  introspective  method  occur  in 
connection  with  Vives's  treatment  of  two  associated  ideas 
[recordatio  gemina].  Of  course,  it  is  not  the  fact,  as  some 
writers  seem  to  suppose,  that  the  doctrine  of  association  of 
ideas  began  with  David  Hartley  or  with  the  Mills  nor  even  with 
Thomas  Hobbes,  or  John  Locke.  This  explanation  of  men- 
tal process,  goes  back,  at  any  rate,  to  Aristotle.  But  it 
may  be  claimed  for  Vives  that  his  development  of  Aristotle's 
theory  marks  the  Renascence  advance.  No  other  author  as 
early  as  Vives  contributed  so  strong  and  comprehensive  an 
exposition  of  it,  as  Vives.  Indeed,  Sir  William  Hamilton, 
the  most  erudite  of  all  British  philosophers,  in  the  history  of 
psychology,  said:  "Vives's  observations  comprise  in  brief, 
nearly  all  of  principal  moment  that  has  been  said  upon  this 
subject  (of  mental  association)  either  before  or  since"* 

Before  Sir  William  Hamilton,  Samuel  Taylor  Coleridge4 
in  his  effort  to  discountenance  Hobbes's  claim  to  be  the  '  ori- 
ginal discoverer'  of  the  law  of  association,  as  advocated  by 
Sir  James  Mackintosh  hit  upon  the  £De  Anima'  of  Vives,  and 
appears  to  have  been  the  first  Englishman  to  have  drawn  at- 
tention to  Vives's  enunciation  of  this  law  of  association  of 
ideas.  This  was  in  1817.  The  words  quoted  by  Coleridge 
from  Vives  are:  Qua  simul  sunt  a  phantasia  comprehensa 
si  alterutrum  occurrat,  solet  secum  alterum  representare. 

1  Vives  is  explaining  that  our  minds  often  travel  more  readily  from  the  less  to  the 
greater  than  vice-versa.     Some  might  think  that  the  house  oposite  to  the  Palace  would 
lead  to  the  thought  of  the  Palace.     But  Vives  pays  a  compliment  to  his  friend,  as  well 
as  expounds  psychology,  when  he  says  his  friend's  house  recalls  the  'greater'  i.  t.,  the 
more  excellent  idea  of  his  friend  and  their  former  talks  together. 

2  Vives  argues  that,  for  this  reason,  in  mnemonics,  the  *  clues '  to  excite  memory 
should  not  be  themselves  of  such  interest  as  to  detain  the  attention  too  much  from  the 
suggestion  of  what  they  are  intended  to  assist  in  recalling. 

3 'The  Works  of  Thomas  Reid'  (including  Hamilton's  'Dissertations'),  1872,  7th 
ed.,  Vol.  II.,  p.  896,  column  i. 

4  In  the  'Biographia  Literaria,'  Chapter  V. 


34°  FOSTER  WATSON 

Coleridge  proceeds  to  regard  Vives  as  "  subordinating  all 
other  exciting  causes  of  association  to  time.  The  soul  pro- 
ceeds '  a  causa  ad  effectum,  ab  hoc  ad  instrumentum,  a  parte 
ad  totum';  thence  to  the  place,  from  place  to  person,  and  from 
this  to  whatever  preceded  or  followed,  all  as  being  parts  of  a 
total  impression,  each  of  which  may  recall  the  other."  Chains 
of  associated  ideas  may  have  the  most  distant  links  connected 
'by  the  same  thought  having  been  a  component  part  of  two 
or  more  total  impressions.'  Vives's  example  quoted  by 
Coleridge  is:  "From  the  idea  of  Scipio  I  come  to  the  thought 
of  the  Turkish  power,  on  account  of  his  victories  in  that  part 
of  Asia  in  which  Antiochus  was  reigning." 

Hamilton,  who  shows  little  mercy  to  Coleridge,  tells  us 
that  the  whole  of  the  latter's  chapter  on  the  history  of  the 
law  of  association  was  'conveyed,'  to  use  the  old  expression, 
from  the  German  Maass,  and  is  a  '  blundering  plagiarism.' 
So,  with  regard  to  Coleridge's  inference  that  Vives  substan- 
tially limits  the  law  of  association  to  that  of  the  sequence  of 
connected  ideas  in  time,  i.  e.7  to  the  phenomena  of  recollection, 
Hamilton  clearly  shows  that  Vives  does  not  so  limit  associative 
ideas  to  time,  or  to  place,  but  he  points  out  their  operation 
6  in  all  the  connections  of  thought  and  feeling* 

The  insight  which  Vives  thus  showed  in  his  exposition  of 
the  law  of  association  of  ideas  prepares  us  for  further  details 
in  his  experiential  account  of  memory.  As  we  have  two 
hands,  so  memory  is  twofold,  and  consists  in  apprehending 
and  retaining.  The  differences  in  memory  amongst  men  are 
implanted  by  nature.  Some  men  like  Hortensius  remember 
words  more  readily;  others,  e.  g.,  Themistocles.  Some 
apprehend  quickly  and  retain  better  the  curious;  others, 
the  simple;  some,  public  affairs,  others,  private  matters; 
some,  the  old,  others,  the  new;  some,  their  own  affairs,  others, 
those  of  others;  some,  vices,  others,  virtues; — each  according 
to  the  proneness  of  his  disposition.  For  he  attends  more 
willingly  and  therefore  more  closely  to  this  or  that,  and  at- 
tention strengthens  memory.  A  natural  bodily  constitution 
is  of  the  highest  importance  to  memory,  and  with  such  were 
endowed  the  great  men  whose  magnitude  of  memory  has  been 


THE  FATHER  OF  MODERN  PSYCHOLOGY  341 

handed  down,  e.  g.,  Themistocles,  Cyrus,  Cineas,  Hortensius. 
This  natural  endowment  is  capable  of  being  strengthened  by 
habits  of  living.  Memory  is  more  tenacious  in  slow  than  in 
quick  minds,  like  an  impression  driven  in  for  a  long  time  on  stone 
or  iron,  but  the  swift  minds  more  readily  bring  back  a  reminis- 
cence. A  deep  descent  into  memory  is  made  by  those  things 
to  which  we  give  close  attention  and  care  when  first  perceived. 
If  anyone  is  in  a  state  of  emotion  or  excitement  on  first  hear- 
ing of  something,  and  this  is  mingled  with  the  memory,  this 
reminiscence  is  easier,  quicker,  longer,  as,  e.  g.,  for  what  has 
entered  the  mind  when  in  a  state  of  violent  grief  the  memory 
is  the  longest,  and  for  that  reason,  adds  Vives,  in  determining 
the  boundaries  of  property  it  is  the  custom  of  some  races  to 
bring  their  boys  there,  and  thrash  them  with  severity,  so 
that  the  boundaries  may  be  more  firmly,  and  the  longer, 
retained  in  memory.  By  practice  and  frequent  meditation 
the  memory  gathers  great  strength.  Unlike  other  gifts 
of  the  mind,  which  do  not  deteriorate  by  rest  and  cessation, 
memory  grows  fainter  and  fainter,  day  by  day,  if  it  is  not 
exercised. 

The  law  of  forgetfulness  is  fourfold,  (i)  When  the  im- 
age painted  in  the  memory  is  utterly  scratched  out;  (2)  when 
it  is  smeared  or  broken  in  pieces;  (3)  when  it  stealthily  evades 
us  in  our  search  for  its  recall;  (4)  when  it  is  covered  over  as 
with  a  veil,  in  disease,  or  in  the  excitement  of  emotion. 
Vives  sketches  the  method  of  recall  of  an  idea;  by  retracing 
as  it  were,  our  steps,  we  may  come  in  thought  to  what  we  are 
seeking.  Thus  from  the  idea  of  a  ring  we  think  of  a  gold- 
smith, from  him  to  a  queen's  collar;  thence  to  a  war  which 
her  husband  waged;  from  the  war  to  the  leaders;  from  the 
leaders  to  their  ancestors  or  children;  thence  to  the  studies 
in  which  the  latter  are  being  exercised.  To  such  series  of  ideas 
there  is  no  end.  These  steps  spread  themselves  widely 
through  all  kinds  of  subjects,  from  cause  to  effect,  and  so  on, 
as  we  have  seen  in  Coleridge's  reference.  Vives,  however, 
gives  an  example,  which  Coleridge  omitted,  but  which  we 
may  note,  since  we  are  emphasizing  the  appeal  to  experience 
made  by  Vives.  "In  thinking  of  the  name  of  Cicero,  there 


342  FOSTER  WATSON 

comes  into  my  memory  the  name  of  Lactantius,  for  he  was  the 
imitator  of  Cicero.  From  him,  I  proceed  to  think  of  the 
copper-plate  artist,  since  his  book  is  said  to  have  been  either 
the  first  or  amongst  the  first  printed  from  copper-plates." 
Remembrance  is  of  two  kinds.  It  is  either  natural,  or 
voluntary,  when  we  pass  freely  from  one  idea  to  another,  or 
it  is  ordered  (jussa)  when  the  mind  makes  an  effort  to  reach 
and  bring  back  some  idea.  Those  ideas  which  occur  in  a 
series  are  more  easily  remembered,  as  for  instance,  in  mathe- 
matics. Verses  are  conducive  to  faithful  retention  on  account 
of  the  rhythm  of  composition,  which  keeps  the  mind  from 
straying  outside  its  limits.  The  art  of  mnemonics  is  based 
on  the  order  of  what  is  committed  to  memory.  It  is  at  this 
point  that  Vives  introduces  his  definition  of  association. 
For  with  regard  to  ideas  'which  have  been  included  in  the 
imagination  [phantasia]  at  the  same  time  if  one  of  the  two 
should  occur,  it  is  wont  to  bring  back  with  it,  the  other.' 
According  to  his  custom,  Vives  illustrates  this  definition. 
"From  the  sight  of  a  place  there  comes  into  the  mind  what 
we  know  once  happened  in  that  place,  or  what  was  situated 
there.  When  something  joyful  happened  along  with  a  voice 
or  sound,  we  are  delighted  when  we  hear  that  same  voice  or 
sound  again.  If  it  was  a  sad  event,  we  are  saddened.  This 
is  also  to  be  noted  in  the  lower  animals,  who  if  they  receive 
something  pleasant,  after  they  have  been  called  by  a  sound, 
they  will  run  towards  it  readily  and  gladly,  on  hearing  the  same 
call  again.  But  if  they  were  beaten,  after  being  called,  they  are 
frightened  by  the  memory  of  the  blows, on  hearing  the  same  call 
again.  Returning  to  memory,  another  factor  in  clear  memory, 
Vives  points  out,  is  the  time-element.  A  distinction  of  times 
is  necessary  in  reminiscence,  otherwise  images  are  confused, 
as  if  in  a  picture,  other  pictures  should  get  painted  on  the 
top,  after  an  interval.  Those  images  which  we  have  received 
with  a  quiet,  leisurely  mind  imprint  their  trace  for  a  longer 
time,  and  more  permanently,  if  we  gave  our  attention  to 
them.  It  is  for  this  reason  that  the  things  we  have  seen  and 
heard  in  early  life  are  recollected  by  us  so  clearly.  For  at 
that  age  the  mind  is  free  from  cares  and  thoughts.  Every- 


THE  FATHER  OF  MODERN  PSYCHOLOGY  343 

thing  is  new.  We  therefore  watched  closely  these  things 
which  won  our  admiration  and  they  sank  deeply  into  the 
mind.  Older  men  are  preoccupied,  and  in  an  *  internal 
agitation  of  thoughts'  so  that  they  cannot  so  restfully  admit 
new  ideas,  or  find  out  readily  the  old  amid  their  experiences. 

In  connection  with  associations  by  similarity,  Vives  is 
impressed  by  the  opportunities  for  error  in  memory  and  in 
thought,  as  we  pass  from  like  to  like.  We  mistake  Georgius 
for  Gregorius;  problema  for  enthymene;  Pindarus  for  Pan- 
darus.  Similarity  may  appear  in  the  beginning,  middle,  or 
end,  of  words.  Or  the  similarity  may  be  in  things,  from  the 
manner  in  which  we  concentrate  our  attention  on  them.  In 
philosophy  we  may  think  of  Xenocrates  for  Aristotle;  in 
speaking  of  the  Carthaginian  Wars  we  may  confuse  Scipio 
with  Q.  Fabius.  In  a  question  of  poverty,  we  may  say  Irus 
instead  of  Codrus.  In  eloquence,  we  may  ascribe  something 
to  Demosthenes  instead  of  to  Cicero.  In  a  matter  of  beauty, 
we  may  speak  of  Narcissus  for  Adonis.  Or  in  a  question  of 
smell,  mistakes  may  be  made  of  garlic  for  onion.  So,  in 
matters  of  times,  actions,  qualities.  Similarity,  therefore, 
disturbs  the  memory,  as  it  does  the  eyes  of  the  body,  so  that 
judgment  is  confused.  Vives  sees  that  errors  can  creep  in  at 
the  *  first  attention'  when  an  idea  is  received  or  at  the  'second 
consideration'  when  reminiscence  wrongly  draws  forth  those 
ideas  which  were  received  as  wholes.  "Yesterday,"  illus- 
trates Vives,  "in  the  market-place,  Peter  of  Toledo  saluted 
me.  I  did  not  notice  the  fact  sufficiently,  nor  remember  it 
accurately.  If  anyone  asks  me:  *  Who  saluted  you  yesterday 
in  the  market-place? '  and  adds  nothing  further,  I  shall  answer 
more  readily  than  if  he  were  to  say:  '  Was  it  John  Manricus  or 
Ludovicus  Abylensis?'  The  labor  thus  becomes  two-fold, 
first  to  reject  what  does  not  fit,  secondly  to  replace  it  by  what 
is  right." 

We  can  thus  see  that  Vives  is  permeated  with  the  idea  of 
an  empirical  and  introspective  method  of  the  modern  type 
in  his  'De  Anima,'  and  that  the  application  of  this  method 
has  taken  him  far  along  the  path  of  development  of  the 
doctrine  of  association  of  ideas,  and  in  the  exposition  of  ob- 


344  FOSTER  WATSON 

servational  aspects  of  memory.  There  are  many  other  views 
of  Vives  which  have  special  interest.  Thus  his  emphasis  on 
the  necessity  of  observing  and  distinguishing  the  great 
variety  of  differences  in  men's  minds  became  the  basis  of  the 
treatise  of  his  fellow  countryman,  Juan  Huarte,  written  in 
1557,  and  translated  into  English1  by  Richard  Carew  in  1594, 
under  the  title  of  the  'Examination  of  Men's  Wits.'  This 
book  following  on  explicit  suggestions  in  Vives's  £De  Anima,' 
demands  that  children's  impulses  and  tendencies,  both  in 
play  and  at  work,  should  be  studied  so  as  to  afford  a  psycho- 
logical basis  for  their  studies  and  after-occupations.  Vives 
distinguishes  carefully  between  the  ratio  speculativa,  whose 
1  end'  is  the  truth  and  the  ratio  practica  whose  end  is  the 
'good.'  The  Spanish  biographer  of  Vives,  Senor  Professor 
D.  Adolfo  Bonilla  y  San  Martin,  points  out  the  parallel 
between  Vives's  view  and  that  afterwards  developed  by  Kant. 
Vives  introduces  a  priori  subjective  forms  of  reason  which 
he  terms  anticipationes  sen  informationes  naturales,  and  as 
Bonilla  remarks,  anticipationes  naturales  is  also  the  term  used 
by  Francis  Bacon  in  'Novum  Organum,'  Book  I.  Nor  will 
theologians  and  philosophers,  if  they  turn  to  Vives's  'De 
Anima,'  pass  by  without  notice  his  treatment  of  the  problems 
of  free-will,  and  of  immortality,  for  they  present  an  interesting 
individual  statement  of  these  problems — of  this  Renascence 
period. 

Educationists  ought  to  realize  that  Vives  writes  in  the 
'De  Anima,'  a  section  which  he  terms  fde  Discendi  Ratione.' 
He  attempts  the  well-trodden  path  of  an  evaluation  of  the 
order  of  intellectual  resources  and  discipline  afforded  by  the 
several  senses.  He  remarks:  "The  course  of  learning  is 
from  the  senses  to  the  imagination,  and  from  that  to  the  mind 
of  which  it  is  the  life  and  nature,  and  so  progress  is  made 
from  singulars  to  combinations,  from  singulars  to  the  univer- 
sal; which  is  to  be  noted  in  boys.  .  .  .  And  so  the  senses  are 
our  first  teachers2  in  whose  home  the  mind  is  enclosed"  It  is 
in  this  section  of  the  'De  Anima'  that  Vives  refers  to  the  ad- 

1  Indirectly,  from  the  Italian  of  Camillo  Camilli. 

2  Cf.  Rousseau's  often-quoted  "Our  first  teachers  of  philosophy  are  our  feet,  our 
hands,  and  our  eyes."     'Emile'  (Payne's  ed.),  p.  90. 


THE  FATHER  OF  MODERN  PSYCHOLOGY  345 

miration,  almost  bordering  on  incredulity,  with  which  he 
heard  that  a  deaf-mute  had  become  taught,  and  he  points 
out  that  the  method  of  learning  necessarily  implied  a  large 
measure  of  self-teaching. 

Whilst  the  psychological  views  of  Vives,  sketched  above, 
are  of  this  most  significant  modern  cast,  yet  it  must  be  stated 
clearly  that  the  general  setting  from  which  they  are  taken  is 
that  of  the  old  Aristotelian  psychology,  and  if  there  are  modi- 
fications in  statement,  these  are  usually  clearly  based  on  scho- 
lastic writers,  for  as  a  Spaniard,  Vives  was  thoroughly  unwilling 
consciously  to  borrow  or  adopt  from  Moorish  sources.  He 
treats  of  'souls'  as  distinguished  from  ' torpid  things'  (or  the 
inorganic  world),  the  distinction  being  founded  on  the  power 
of  self-movement.  He  is  thus  provided  by  the  Aristotelian- 
Scholastic  psychologists  with  (i)  the  anima  alens  of  the  plants, 
(2)  the  anima  sentiens  of  zoophytes,  (3)  the  anima  cogitans 
of  birds  and  four-footed  beasts  and  (4)  the  anima  rationalis 
of  man.  The  soul  of  man  is  the  'form'  of  which  the  body  is 
the  'matter.'  The  human  body  therefore  is  a  potentiality, 
which  is  actualized  by  the  union  with  it  of  the  soul.  But  this 
principle  of  the  form  giving  actuality  to  the  potentiality  of 
suitable  matter  is  characteristic  of  all  life,  e.  g.,  in  plants, 
zoophytes,  birds,  beasts — up  to  and  including  man.  The 
lowest  kinds  of  life,  e.  g.,  plants,  have  the  motions  of  nutrition, 
growth  and  decay.  Animals,  in  addition,  have  sensation, 
and  developments  from  sensations.  Man  combines  all  these 
stages,  including  the  appetency  which  springs  from  sensation, 
cognition  and  reasoning.  The  soul  of  man  is  therefore  an 
epitome  of  all  lower  life  and  also  possesses  psychical  ingredients 
of  its  own.  Hence,  an  investigation  is  necessary  into  the  vege- 
tative 'soul,'  and  the  'animal'  soul,  as  well  as  the  human  soul. 
Thus  the  physical  phenomena  of  nutrition,  growth,  decay,  gen- 
eration, sensation  (in  general)  and  the  special  senses  (and  the 
hierarchy  amongst  them),  are  passed  in  review,  then  'interior 
cognition'  including  imagination,  phantasia  (into  which  angels, 
good  and  bad,  insinuate  themselves),  the  sensus  communis,  the 
cognitive  judgment  and  reason.  Vives  then  offers  his  defini- 


346  FOSTER  WATSON 

tion  of  the  soul1  and  makes  the  usual  inquiry  as  to  the  seat 
of  the  soul,  deciding,  with  Aristotle,  that  it  ' informs'  the 
whole  body;  though  certain  functions  are  localized,  e.  g.,  the 
front  part  of  the  brain  is  the  seat  of  phantasia  and  in  the  back 
part  of  the  brain  memory  is  localized,  and  so  on. 

The  above  topics  comprise  the  contents  of  Book  I.  of 
Vives's  'De  Anima.'  Book  II.  is  devoted  to  the  rational 
soul  and  its  faculties.  Man  has  been  created  for  eternal 
felicity  and  provided  with  the  means  for  accomplishing  it. 
This  implicitly  demands  the  intelligence  to  know  the  good,  the 
memory  to  retain  that  knowledge,  and  the  will  to  act  it  out 
in  life.  We  thus  have  the  trinity  of  the  soul.  Vives  then 
describes  in  detail  the  functions  of  the  simplex  intelligentia 
(simple  apprehension),  memory  and  reminiscence,  composite 
ideas,  reason,  judgment,  mental  ability  and  its  individual 
varieties,  speech,  the  method  of  learning  (in  which  Vives 
inquires  why  there  are  so  few  learned  people),  knowledge, 
contemplation,  will  (in  which  occurs  the  discussion  on  its 
freedom),2  on  the  mind  in  general,  on  sleep  and  dreaming, 
'habit,'  old  age,  length  of  life,  death,  and  the  immortality  of 
the  human  soul. 

In  the  third  book  of  the  'De  Anima,'  the  subject  of  which 
is  the  emotions  or  passions  (affectus),  Vives  undoubtedly 
followed3  St.  Thomas  Aquinas.  We  have  seen  that  Vives 
regarded  the  intellect  as  supplying  knowledge  as  to  the  good, 
which  the  will  was  to  carry  into  effect.  We  are,  therefore, 
prepared  to  find  that  'passions'  are  looked  upon  in  their 
relation  to  the  supreme  end  to  be  achieved  in  volition.  They 
are  defined  by  Vives  as  'the  natural  faculties  of  our  soul  by 
which  we  are  carried  towards  the  good  and  endeavor  to  avoid 

1  This  follows  substantially  the  teaching  of  Aristotle.    Animam  esse  agens  praeci- 
pium,  habitans  in  corpore  apto  ad  vitam. 

2  It  is  worth  noting  that  Vives  strongly  protests  against  the  doctrine  current  long 
after  his  age,  that  the  will  is  controlled  or  influenced  by  the  motions  of  the  stars.     The 
significance  of  the  protest  is  only  realized  when  we  remember  that  Tycho  Brahe, 
Kepler  and  even  Galileo  'cast  nativities.* 

8  Aristotle  is  out  the  question.  As  Mr.  Hicks  says  Aristotle  'exalted  the  cognitive 
element,  while  his  treatment  of  the  emotions  and  the  will  is  wholly  inadequate  even  if 
the  ethics  and  the  rhetoric  be  called  in  to  redress  the  balance.'  Aristotle  de  Anima, 
p.  LXXII.  On  the  parallels  between  Vives  and  St.  Thomas  Aquinas  see  Roman  Fade, 
'Die  Affectenlehre  des  J.  L.  Vives,'  Miinster  i.  W.,  1893. 


THE  FATHER  OF  MODERN  PSYCHOLOGY  347 

the  evil.'  The  close  relation,  therefore,  between  psychology 
and  ethics  is  evident.  Vives's  treatment  of  the  passions, 
though  based  on  St.  Thomas  Aquinas,  is  yet  largely  supple- 
mented by  his  own  introspection  and  observation. 

Whilst  thus  he  tends  to  emphasize  the  interest  in  the 
description  and  analysis  of  the  separate  emotions,  and  to  give 
the  result  of  his  wide  intercourse  with  men  of  very  varied 
kinds,  he  has  not  been  so  thoroughgoing  in  his  psychology  of 
emotion  in  general.  He  does  not  offer  an  elaborated  theory 
of  the  passions  like  Descartes  and  Spinoza,  leading  in  the  one 
case  to  a  discussion  of  emotion  in  the  abstract,  and  in  the 
other  to  an  a  priori  mathematically-based  theory,  but  he  is 
quite  as  comprehensive  and  at  points  shows  depth  of  empirical 
interest,  which  place  him  in  the  direct  line  of  continuity  be- 
tween the  Scholastics  and  the  modern  descriptive  school  of 
psychology,  in  the  treatment  of  the  passions.  Vives  reduces 
all  the  passions  to  two,  love  and  hate.  All  that  stirs  and 
stimulates  towards  the  good,  comes  from  the  incitement  of 
love,  and  all  that  stirs  to  evil,  from  the  passion,  in  some 
form,  of  hate.  Yet  Vives  describes  fully  and  separately  the 
passions :  good-will,  respect,  sympathy,  gaiety,  hope,  laughter, 
annoyance,  scorn,  anger,  hatred,  envy,  jealousy,  indignation, 
vengeance,  cruelty,  sadness,  mourning,  fear,  shame,  pride. 
Vives  is  strongly  attracted  to  the  Platonic  treatises,  especially 
the  'Phsedrus'  and  'Symposium.'  The  value  of  the  third 
book,  as  with  the  other  two,  is  in  its  empirical  method,  for 
it  also  contains  numerous  observations,  personal  illustrations 
based  on  Vives's  own  introspective  experiences.  The  dis- 
tinguished psychologist  Harold  HofFding1  in  the  section  on 
the  psychology  of  the  feelings,  whilst  discussing  the  topic  of 
laughter,  quotes  Vives,  who  described  himself  as  unable  to 
refrain  from  laughter  as  he  first  tastes  food  after  a  long  fast 
(*De  Anima,'  Bk.  IIP).  And,  again,  HofFding  recalls  the 
observation  of  Vives,  that  what  man  expresses  by  laughter 
may  be  expressed  by  animals  in  other  ways3  (e.  g.,  by  wagging 
the  tail). 

1  'Outlines  of  Psychology'  translated  by  Mary  E.  Lowndes,  1891,  pp.  291-2. 
2 'Opera,' III.,  p.  469. 
3 'Opera, 'III.,  p.  470. 


348  FOSTER  WATSON 

In  his  professedly  psychological  work — throughout  the 
three  books  of  the  fDe  Anima' — Vives  discloses  himself  as 
the  pioneer  of  the  modern  empirical  method  in  psychology. 
But  we  only  realize  the  full  sense  of  conviction,  which  ani- 
mated Vives  in  his  use  of  the  method  of  introspection  and 
observation,  when  we  further  note  in  his  other  writings,  his 
constant  application  of  the  same  method  in  the  ordinary  affairs 
of  life.  He  applied  psychological  principles  to  professional 
practice,  to  individual  conduct,  and  particularly  to  the  func- 
tion of  teaching.  In  other  words,  in  practical  affairs,  he 
sought  to  introduce  psychological  precepts  and  methods,  to 
create  a  habit  of  introspection  which  might  be  turned  to  use — 
to  create  an  atmosphere  of  psychology,  to  thinkpsychologically. 

No  writer  of  the  Renascence  period  was  so  distinguished 
by  his  application  of  psychology  to  education,  as  Vives.  In 
his  'Transmission  of  Knowledge'  ('De  Tradendis  Disciplinis,' 
1531)  he  is  permeated  with  the  desire  to  bring  education  to  a 
psychological  basis.  We  have  seen  that  his  account  of  the 
memory  was  an  outstanding  feature  in  his  de  Anima.  But  in 
dealing  with  the  subject  from  an  educational  point  of  view, 
he  is  in  accordance  with  the  most  modern  of  writers  in  pointing 
out  that  both  quick  comprehension  and  faithful  retention 
in  memory  are  helped  by  a  right  arrangement  of  facts.  This, 
he  adds,  is  just  that  art  of  memory  '  which  beasts  are  said 
to  lack.'  His  rules  for  the  cultivation  of  memory  have  not 
lost  their  suggestiveness.  For  instance,  he  says:  "What  we 
want  to  remember  must  be  impressed  on  our  memory  while 
others  are  silent.  We  need  not  be  silent  ourselves,  for  those 
things  which  we  have  read  aloud  are  often  more  deeply 
retained.  ...  It  is  a  useful  practice  to  write  down  what  we 
want  to  remember,  for  it  is  not  less  impressed  on  the  mind 
than  on  the  paper,  by  the  pen.  The  attention  is  kept  fixed 
longer  by  the  fact  that  we  are  writing  it  down."  "  Great  is 
the  help  to  memory  if  reasons  are  associated  with  the  matter 
taught."  We  have  seen  that  Vives  recognizes  interest  as  a 
strong  stimulus  to  the  attainment  of  knowledge.  He  goes 
far  in  the  direction  of  Herbart  in  the  recognition  of  interest 
not  merely  as  a  means  in  the  acquisition  of  knowledge  but  also 


THE  FATHER  OF  MODERN  PSYCHOLOGY  349 

in  the  advocacy  of  a  wider  scope  of  interests  as  the  outcome  of 
our  studies.  Vives  in  his  story  of  Charles  Virulus  the  school- 
master of  Louvain  is  as  modern  in  significance  as  Herbart 
himself.  When  a  pupil's  parent  came  to  visit,  especially  to 
dine  with  him,  he  made  a  point  of  finding  out  what  his  visitor's 
work  and  interests  were  and  prepared  himself  carefully  to  con- 
verse on  matters  familiar  to  his  guest,  and  lead  him  to  speak 
freely  on  what  was  best  known  to  him.  "He  would  thus  hear 
in  the  briefest  time  details  which  he  could  scarcely  have 
gleaned  from  the  study  of  many  years." 

Education  with  Vives  is  not  the  preparation  for  a  career, 
but  the  increase  in  practical  wisdom  of  life  and  the  preparation 
for  moral  excellence.  In  each  school  masters  should  meet 
four  times  a  year  and  discuss  the  'nature'  of  each  boy  and 
then  apply  the  boy  to  those  studies  for  which  he  seems  most 
fit.  The  fruit  of  studies  is  not  honor  or  money,  but  the 
culture  of  the  mind — 'a  thing  of  exceeding  great  and  in- 
comparable value — that  the  youth  may  become  more  learned 
and  more  virtuous  through  sound  teaching.'  Boys  should 
only  at  first  be  taken  on  trial  in  the  school.  The  teachers  are  to 
determine  who  are  fit  and  who  unfit  for  learning.  As  Ascham 
maintained,  Vives  previously  urged  that  the  slow  wit  is  usually 
the  surest.  The  wonderful  variety  of  dispositions  in  boys 
requires  the  closest  attention  of  teachers,  in  'choosing' 
scholars.  Yet  there  is  scarcely  anyone  who  will  not  profit 
by  being  taught,  if  the  right  sort  of  teaching  is  given  him. 
Probably  no  Renascence  writer  has  taken  so  much  notice  of 
the  problem  of  the  feeble-minded,  the  deaf  and  dumb,  the 
blind,  as  Vives,  though  naturally  he  has  not  been  able  to  sug- 
gest the  most  effective  lines  of  training  in  each  case.  But  his 
firm  grip  of  the  principle  of  suiting  instruction  to  the  individual 
capacity  puts  him  in  the  direction  of  perceiving  the  problem 
involved.  Vives,  again,  sees  clearly  that  the  problem  of 
education  is  essentially  that  of  self-activity.  He  requires  the 
pupil  to  keep  paper  notebooks,  in  which  he  gathers  for  himself 
the  main  materials  of  his  own  instruction.  His  notebooks 
must  have  divisions  and  heads,  and  be  provided  by  himself 
with  indexes.  In  these  he  must  enter,  under  proper  heads, 


350  FOSTER  WATSON 

all  he  learns  from  teachers  and  books.  In  other  words,  he 
must  largely  make  his  own  text-books.  He  presents  a  well 
thought  out  psychology  of  school  punishment,  and  indeed  his 
psychology  of  examinations,  if  we  may  so  call  it,  is  in  advance 
of  present-day  methods,  for,  instead  of  pitting  boy  against 
boy  (when  he  has  emphasized  the  great  variety  of  original 
mental  capacity)  he  logically  requires  the  comparison  of  the 
boy  with  himelf  at  an  earlier  stage.  "Let  scholars  keep  what 
they  have  written  in  earlier  months,  in  order  to  compare  it 
with  that  written  at  a  later  month,  so  that  they  may  perceive 
the  progress  made,  and  persevere  in  the  way  of  improvement." 
Thus,  whilst  Vives  sees  the  overwhelming  importance  of 
building  up  the  art  of  pedagogy  upon  a  sound  psychological 
basis,  he  by  no  means  limits  the  value  of  the  application  of 
psychology  to  the  work  of  the  schoolmaster.  The  knowledge 
of  psychology  is  essential  to  all  who  have  to  deal  with  spiritual 
affairs.  "The  study  of  man's  soul  exercises  a  most  helpful 
influence  on  all  kinds  of  knowledge,  because  our  knowledge  is 
determined  by  the  intelligence  and  grasp  of  our  minds,  not  by 
the  things  themselves."  The  text-books  for  psychology  recom- 
mended by  Vives  are  the  sacred  writers  of  the  Bible,  and  the  three 
books  of  Aristotle's  '  De  Anima '  (especially  Books  II.  and  III.). 
Other  writers  to  be  read  are  Alexander,  Themistius,  Timseus 
of  Locris,  and  Plato's  ' Timseus/  Proclus,  Chalcidius,  and  of 
the  Renascence  writer,  Marsilius  Ficinus,  who  will  act  as  guide 
for  Plotinus.  The  physician,  to  Vives,  is  on  the  very  border- 
land of  nature-study  and  soul-study,  and  must  be  at  home  in 
both.  But  the  psychological  aspect  must  be  present  not  only 
in  his  studies,  but  in  his  professional  habits.  He  must 
himself  "not  be  in  infirm  health,  not  pallid  in  countenance, 
so  raising  the  suggestion  put  in  the  sacred  Gospel:  ' Physician 
heal  thyself.'  Further  let  the  doctor  be  clothed  neatly 
rather  than  sumptuously.  At  the  first  sight  of  his  patient 
he  will  immediately  take  in  his  appearance  and  constitution, 
age  and  vitality.  All  necessary  information  he  will  gather 
in  an  urbane  and  affable  fashion.  He  will  listen  with  patience. 
.  .  .  He  will  neither  exchange  views  nor  discuss  with  other 
physicians  in  the  presence  of  patients,  or  of  lay-people,  who 


THE  FATHER  OF  MODERN  PSYCHOLOGY  35 * 

know  not  which  side  to  take.  To  do  so,  easily  raises  a  '  certain 
despair'  in  them  and  a  hatred  against  knowledge,  'which 
comes  to  be  regarded  as  a  matter  of  uncertainty.'  ' 

In  the  case  of  the  historian,  wars  and  battles  are  to  be 
regarded  as  'cases  of  theft.'  The  historian  should  study 
peaceful  affairs,  trace  the  glory  and  wisdom  of  virtuous  acts 
and  note  the  disgrace  of  evil-doers.  The  wisdom  of  great 
statesmen,  and  those  who  have  excelled  in  'good  arts,' 
philosophers,  saints  of  the  faith,  and  all  that  has  been  said 
in  practical  affairs  should  be  studied  with  the  full  force  of 
weighty  intellect  and  judgment.  For  "it  is  unworthy  to 
hand  over  to  our  memories  historical  actions  due  to  our  pas- 
sions, and  not  also  to  study  what  took  place  as  the  outcome 
of  the  rational  judgment."  History  discloses  the  essential 
nature  of  human  beings,  and  discloses  the  manifestations  of 
the  affections  and  judgment  of  the  human  mind,  in  short,  the 
subject  has  a  distinctly  psychological  basis. 

Again,  the  politician  and  economist  have  to  study  the  dis- 
positions and  minds  of  the  people.  Herein  is  the  predominant 
value  of  experience.  "  Sometimes  old  men  converse  with  one 
another  in  an  experienced  way  and  allow  youth  to  listen." 
This  is  a  privileged  method  of  study  to  youth,  if  they  kept  free 
from  the  company  of  cavillers  and  obstinate  dialecticians. 
"For  a  man  to  be  more  anxious  about  achieving  a  dialectic 
victory  than  of  discovering  truth  leads  to  the  ruin  of  practical 
wisdom,  as  indeed  Cicero  has  said."  Vives  points  out  the 
mental  characteristics  desirable  in  the  administrator,  and  for 
the  study  of  political  philosophy  recommends  not  only  Plato 
and  Aristotle  and  other  classical  writers,  but  also  the  'Utopia' 
of  Sir  Thomas  More  and  Erasmus's  'Christiani  Principis 
Institutio.'  Equally  clearly  the  lawyer  must  be  a  psychol- 
ogist. He  must  understand  "the  common  nature  of  man- 
kind, the  views  and  customs  of  many  kinds  of  people,  espe- 
cially of  his  own  country.  This  is  brought  about  by  wide 
experience  in  seeing,  hearing,  observing  things;  through  read- 
ing of  the  deeds  of  ancestors  and  varieties  of  changes  which 
have  befallen  the  state.  Such  men  need  alert  minds  and  keen 
judgments,  so  as  to  observe  and  to  estimate  circumstances,  one 
by  one." 


352  FOSTER  WATSON 

In  all  these  instances  Vives's  introduction  of  psychological 
observation  bears  a  modern  aspect,  and  affords  illustration 
of  the  attraction  which  he  felt  towards  the  empirical  stand- 
point and  self-exercised  thought  on  the  environment  rather 
than  the  older  type  of  abstract,  metaphysical  explanation  or 
discussion  of  the  more  ultimate  foundation  of  psychological 
phenomena.  The  most  marked  characteristic  of  the  early 
Renascence  writers  is  the  backward-looking  concentration  on 
the  golden  age  of  Roman  and  Greek  culture  and  knowledge. 
In  a  notable  passage1  however  we  find  Vives  exclaiming: 
"The  student  should  not  be  ashamed  to  enter  into  shops  and 
factories,  and  to  ask  questions  from  craftsmen,  and  to  get  to 
know  about  the  details  of  their  work.  Formerly,  learned 
men  disdained  to  inquire  into  those  things  which  it  is  of  such 
great  import  to  life  to  know  and  remember.  This  ignorance 
grew  in  succeeding  centuries  up  to  the  present  ...  so  that 
we  know  far  more  of  the  age  of  Cicero  or  of  Pliny  than  of  that 
of  our  grandfathers."  His  keen  interest  in  the  experiential 
side  of  psychology,  therefore,  infused  itself  into  his  whole 
outlook,  in  wishing  to  get  an  intellectual  grip  of  the  problems 
of  the  human  mind,  and  its  manifestations,  in  its  relations  to 
its  own  growth  and  development,  and  also  in  its  actions  and 
reactions,  in  connection  with  its  environment.  No  doubt  he 
believed  that  the  glorious  achievements  and  experiences  of 
the  past  threw  light  on  those  questions,  perhaps  to  a  degree 
which  has  been  lost  in  modern  times,  but  Vives's  psycho- 
logical attitude  towards  life,  in  its  present  environment  is 
clearly  modern,  rather  than  ancient  or  mediaeval. 

In  England,  Vives's  name  has  fallen  into  undeserved 
oblivion.  For  the  Spaniard  of  Valencia  made  his  home  in 
this  country  for  portions  of  the  year  from  1523  to  1528,  the 
year  in  which  he  had  to  withdraw  from  England,  on  account  of 
his  known  adhesion  to  the  cause  of  Queen  Catharine  of  Aragon, 
who  had  such  a  belief  in  his  abilities  that  she  desired  him 
to  act  as  her  advocate  in  the  court,  so  adroitly  consti- 
tuted by  Henry  VIII  to  try  her  case.  During  his  visits 
in  England,  Vives  lectured  on  rhetoric  at  Oxford,  where 

1  'De  Tradendis  Disciplinis,'  Book  IV.,  Chapter  6.     'Opera,'  VI.,  p.  374. 


THE  FATHER  OF  MODERN  PSYCHOLOGY  353 

he  was  associated  with  Corpus  Christi  College.  He  was  one 
of  the  friends  of  Cardinal  Wolsey,  and  of  Sir  Thomas  More. 
Yet,  curiously,  as  we  have  seen,  it  is  to  a  representative  of 
Scotland,  Sir  William  Hamilton,  that  Vives  particularly 
owes  his  acknowledgment,  in  the  last  century,  though 
another  Scot,  Dugald  Stewart,  perhaps  even  more  fittingly 
brings  out  the  modern  aspect  of  Vives,  in  the  striking  passage: 
"Of  all  the  writers  of  the  sixteenth  century,  Ludovicus 
Vives  seems  to  have  had  the  liveliest  and  the  most  assured 
foresight  of  the  new  career  on  which  the  human  mind  was 
about  to  enter.  The  following  passage  from  one  of  his  works1 
would  have  done  no  discredit  to  Francis  Bacon's  'Novum 
Organum':  'The  similitude  which  many  have  fancied  between 
the  superiority  of  the  moderns  to  the  ancients,  and  the  ele- 
vation of  a  dwarf  on  the  back  of  a  giant  is  altogether  false 
and  puerile.  Neither  were  they  giants,  nor  are  we  dwarfs, 
but  all  of  us  men  of  the  same  standard, — and  we  the  taller  of 
the  two,  by  adding  their  height  to  our  own :  Provided  always, 
that  we  do  not  yield  to  them  in  study,  attention,  vigilance  and 
love  of  truth;  for,  if  these  qualities  be  wanting,  so  far  from 
mounting  on  the  giants'  shoulders,  we  throw  away  the  ad- 
vantages of  our  own  just  stature,  by  remaining  prostrate  on 
the  ground."1 

1  'De  Causis  Corruptarum  Artium,'  Bk.  I.,  Chap.  5.     'Opera,'  VI.,  p.  39. 


AN  INVESTIGATION  OF  THE  LAW  OF  EYE- 
MOVEMENTS 

BY  MILDRED  WEST  LORING1 

The  first  investigation  of  eye-movements  was  made  in 
1826  by  Johannes  Miiller  (i).  He  stated  that  the  eyes  in 
their  movements  do  not  rotate  about  their  long,  i.  e.,  sagittal 
axes.  He  said:  "I  have  convinced  myself,  while  observing 
various  points  on  the  white  of  the  moving  eye,  which  were 
marked  beforehand  with  ink,  that  the  eye,  through  action  of 
the  oblique  muscles,  does  not  rotate  about  its  long  axis." 
In  1838,  however,  Hueck  (2)  demonstrated  the  compensatory 
rotation  of  the  eyes  around  the  line  of  sight,  by  observing 
that  a  given  horizontal  blood-vessel  on  the  conjunctiva  re- 
mained horizontal  even  when  the  head  was  inclined  to  the 
right  or  left.  Burow  (3),  1841,  reached  the  same  conclusion 
using  his  own  paralyzed  iris  for  the  demonstration.  But 
Ruete  (5),  in  1846,  like  Miiller,  got  negative  results,  using 
after-images  for  a  criterion.  Donders,  (7)  1848,  showed  his 
work  to  have  been  careless,  and  demonstrated  the  well- 
known  principle,  that  the  after-image  of  a  vertical  strip 
remains  parallel  to  itself,  with  vertical  and  horizontal  move- 
ments of  the  eyes,  but  with  oblique  movements,  becomes  itself 
oblique.  He  however  formulated  no  law. 

It  remained  for  Listing  to  put  the  law  concisely  in  the 
form  now  known  as  Listing's  Law,  although  he  did  not  prove 
it,  or  publish  it  himself.  It  first  appeared  in  this  form  in  an 
article  by  Ruete  (n)  in  1855,  in  which  he  says:  "The  principle 
of  the  mechanism  of  the  eye  can  be  expressed  according  to 
Listing  in  the  following  simple  way;  'From  the  above-men- 
tioned normal  position  of  the  eye  which  may  be  called  the 
primary,  the  eye  will  be  moved  into  any  other  secondary 
position  by  the  cooperation  of  the  six  muscles,  in  such  a  way 

1  The  results  of  this  paper  were  obtained  in  the  psychological  laboratory  of  the 
University  of  Washington,  1912-13,  under  the  direction  of  Dr.  H.  C.  Stevens. 

354 


LAW  OF  EYE-MOVEMENTS  355 

that  this  displacement  can  be  represented  as  the  result  of  a 
rotation  about  a  definite  axis  different  from  the  above  three, 
which  always  passes  through  the  center  of  the  eye,  and  is 
perpendicular  to  the  primary  and  secondary  position  of  the 
optic  axis,  so  that  each  secondary  position  of  the  eye  stands 
in  such  a  relation  to  the  primary,  that  the  rotation  projected 
on  the  optic  axis  will  equal  zero." 

Meissner  (9),  in  1854,  was  the  first  to  use  the  method  of 
double  images,  which  he  observed  are  not  parallel  for  a  given 
object  with  near  or  far  fixation.  The  inclination  of  the  two 
images  he  took  as  representing  the  torsion  of  the  two  eyes 
about  the  line  of  sight.  Both  Meissner  (13),  (1860)  and  Pick 
(12),  (1858),  investigated  the  subject  by  means  of  the  change 
of  orientation  of  the  blind  spot  with  eye-movements.  Pick's 
results  are  irregular,  and  he  says  that  the  movement  of  the 
eyes  is  not  a  simple  geometrical  one,  about  a  definite  axis,  as 
Meissner  held,  but  that  it  is  a  physiological  change  of  position, 
whose  beginning  and  end  only,  we  know.  Meissner  found 
his  results  to  be  similar  to  those  of  Listing. 

The  next  important  work  on  eye-movements  was  done  by 
Wundt  (14)  in  1862.  He  used  the  method  of  after-images, 
and  presented  the  theory  that  the  eye  rotates  to  such  a  degree 
as  to  allow  it  to  take  the  desired  position  of  the  line  of  sight 
with  the  least  muscular  effort.  He  found  a  slight  torsion 
inward  for  movements  of  the  eyes  vertically  above,  and  torsion 
outwards  for  movements  vertically  below.  Helmholtz  (15), 
in  1863,  denied  the  reliability  of  Wundt's  hypothesis,  owing 
to  individual  differences  in  muscle  strength,  and  the  general 
unreliability  of  the  muscle  sense.  He  preferred  to  state  the 
facts  in  the  form  of  Bonder's  law,  which  says:  When  the 
position  of  the  line  of  sight  in  relation  to  the  head  is  given,  we 
have  a  definite  and  unchangeable  amount  of  rotation. 

Volkmann  (16),  in  1864,  attacked  the  problem  somewhat 
after  the  fashion  of  Meissner,  using  two  rotating  discs,  one 
for  each  eye,  on  each  of  which  was  marked  a  diameter.  These 
were  rotated  till  judged  parallel,  for  any  given  convergence, 
and  the  real  torsion  thus  determined.  The  torsion  as  ex- 
pressed by  its  effect  on  the  two  diameters  placed  vertical, 
was  as  follows: 


356  MILDRED  WRING 

Primary  position 2°.2i 

30°  above  to  the  right 2°.74 

30°  above  to  the  left 2°.92 

30°  below  to  the  left i°.3 1 

30°  below  to  the  right i°.4O 

This  small  amount  of  variation  accounts,  he  says,  for  the 
difficulty  of  using  after-images. 

Helmholtz  (17),  1866,  using  after-images,  got  the  following 
results: 

A.  Turning  the  eyes  to  the  right  above  or  left  below 

1.  After-image  of  horizontal  line  is  turned  to  the 

left. 

2.  After-image  of  vertical  line  is  turned  to  the 

right. 

B.  Turning  the  eyes  to  the  left  above  or  right  below 

1.  After-image  of  horizontal  line  is  turned  to  the 

right. 

2.  After-image  of  vertical  line  is  turned  to  the  left. 
In  1868,  Hering  (18)  published  his  results  on  binocular 

vision.  |  In  the  main  he  agrees  with  Helmholtz.  He 
worked  with  (a)  after-images,  using  parallel  lines  of  sight, 
observing  the  customary  phenomena  of  Listing's  figure,  (b) 
double  images,  using  convergent  lines  of  sight.  His  general 
conclusion  was  that  Listing's  Law  holds  for  parallel  lines  of 
sight,  but  not  for  convergence  lines  of  sight.  According  to 
him,  then,  Donder's  law  is  invalid,  inasmuch  as  it  maintains 
a  constant  torsional  value  for  a  fixed  position  of  the  line  of 
regard  in  relation  to  the  head. 

Le  Conte  (20),  in  1881,  published  a  severe  criticism  of 
Helmholtz's  version  of  Listing's  Law,  and  framed  it  in  terms 
exactly  opposite  to  those  of  Helmholtz.  The  whole  occasion 
of  the  difference  of  conclusion  rests,  as  Le  Conte  shows,  on  the 
fact  that  he  has  used  the  normal  spherical  surface  for  pro- 
jection of  the  after-images,  while  Helmholtz  stated  the  law  for 
projection  on  a  plane  surface.  Le  Conte  denies  all  real  rotation 
about  the  sagittal  axis.  It  is  only  apparent,  he  says,  and 
attributes  it  to  a  rotation  about  some  axis  perpendicular  to 
the  sagittal  axis,  which,  because  we  observe  all  the  movements 
of  a  spherical  surface  like  the  eyeball  from  one  point  of  view. 


LAW  OF  EYE-MOVEMENTS  357 

we  interpret  as  rotations  about  the  line  of  sight.  So  Le  Conte 
concluded  there  was  no  torsion  with  parallel  lines  of  sight; 
but  for  convergence  he  finds  not  only  an  apparent  but  a  real 
torsion  about  the  line  of  sight. 

One  of  the  most  recent  studies  on  eye-movements  has  been 
made  by  Bernice  Barnes  (23)  in  1905,  at  the  University  of 
Michigan.  Her  apparatus  which  she  calls  a  torsio-meter, 
consisted  of  'an  iron  arc  of  180°,  one  meter  in  diameter, 
mounted  on  a  standard,  so  that  its  center  may  be  directly  in 
front  of  the  eye  of  the  subject,  who  is  seated  before  it.'  The 
arc  could  be  swung  into  horizontal,  vertical  and  oblique  posi- 
tions. It  was  fitted  with  a  telescope  which  was  directed  at 
the  observer's  eye.  The  latter  seated  himself  in  front  of  the 
arc,  with  head  firm;  a  thread  stretched  between  the  extremities 
of  the  arc  served  to  determine  the  center  of  the  arc,  at  which 
point  the  observer  kept  the  pupil  of  his  eye.  The  cross-hair 
in  the  telescope  was  set  in  coincidence  with  a  line  on  the  iris, 
which  reading  was  taken  as  zero.  Then  the  telescope  was 
changed  in  position,  and  the  eyes  were  again  directed  at  the 
telescope.  The  cross-hair  in  the  telescope  was  set  again  on 
the  same  line  on  the  iris.  In  this  way  any  real  torsion  of  the 
eye  about  its  sagittal  axis  was  determined.  Miss  Barnes 
found  real  torsion  for  every  position  different  from  the  primary 
position,  even  with  parallel  lines  of  sight,  a  conclusion  very 
different  from  Listing  and  his  successors'.  Her  chief  con- 
clusions are  these: 

1.  There  is  a  contradiction  between  Listing's  and  Bonder's 
Laws  for  torsion  in  eye-movement. 

2.  Experiments  by  the  after-image  method  seem  to  con- 
firm Listing's  Law.     But  there  are  two  sources  of  error — 
inaccuracies  in  measurement,  and  false  torsion,  which  it  is 
difficult  to  make  allowances  for. 

3.  More  accurate  direct  measurements  show  that  there 
is  always  torsion  with  rotation,  and  the  amount  of  torsion  is 
proportional  to  the  amount  of  rotation. 

4.  Donder's  law  holds. 

Miss  Barnes's  work  is  interesting  for  the  reason  that 
she  found,  even  with  parallel  lines  of  sight,  an  invariable  real 


358  MILDRED  WRING 

torsion  with  movements  away  from  the  primary  position  in 
any  direction  whatever.  Yet  a  closer  analysis  of  her  results 
shows  certain  ambiguities. 

1.  There  is  nothing  in  her  article  to  show  which  eye  of 
the  observer  was  used  in  the  experiment,  or  whether  both 
were  used  indifferently.1     This  is  an  important  point,  for  it  is 
possible  that  the  two  eyes  undergo  torsion  symmetrically, 
but  in  opposite  senses,  when  the  lines  of  sight  are  either 
parallel  or  converged.     An   adequate  interpretation  of  her 
results  is  impossible  without  a  knowledge  of  this  point. 

2.  Her  results  show  that  there  are  some  regions,  for  in- 
stance between  o°  and  30°  to  the  right  above,  where  the  sense 
of  the  torsion  changes,  for  at  o°  it  is  to  the  right  and  at  30° 
it  is   to  the  left.     This   must  indicate  one  of  two   things; 

(a)  that  somewhere  between  o°  and  30°  there  is  no  torsion  at 
all,  this  position  being  at  the  point  where  the  direction  of  the 
line  of  sight  changes  from  right  to  left.     This  point,  mathe- 
matically speaking,  could  be  called  the  point  of  inflection. 

(b)  Otherwise  the  phenomenon  must  indicate  a  region  in  the 
field  of  vision  such  that,  if  one  directs  the  line  of  sight  there, 
the  sense  of  the  torsion  depends  on  chance,  that  is,  it  is  as 
likely  to  be  to  the  right  as  to  the  left  and  cannot  be  predicted. 
Since  Miss  Barnes  denies  any  direction  in  which  there  is  no 
torsion,  the  first  alternative  is  for  her  out  of  the  question. 
She  would  of  necessity  have  to  accept  the  second.     But  this, 
however,  violates  Donder's  Law,  which  Miss  Barnes  upholds, 
inasmuch  as  the  law  mentioned  demands  a  constant  torsional 
value  for  every  given  position  of  the  line  of  regard. 

The  only  conclusion  that  can  be  drawn  from  Miss  Barnes's 
work  is  that  further  investigation  is  necessary  in  the  above- 
mentioned  regions  of  the  fields  of  vision,  using  each  eye,  and 
comparing  the  results  for  the  two  eyes. 

Wichodzew  (24),  1912,  has  recently  contributed  to  the 
subject.  He  has  used  the  size  of  the  field  of  vision  (both 
monocular  and  binocular)  to  determine  the  influence  on  eye- 
movements  of  the  inclinations  of  the  head  to  the  shoulder. 
His  main  conclusions  are: 

1 1  have  since  learned  that  only  one  eye  of  the  subject  was  used,  but  which,  is  not 
recalled  by  the  author. 


LAW  OF  EYE-MOVEMENTS  359 

1.  There  is  a  compensatory  torsion  (Raddrehung)  of  the 
eyes  about  the  sagittal  axis,  which  causes  a  change  in  the 
mutual  relation  of  the  fixation  points  of  the  eye  muscles  and 
so  hinders  the  eye  movements. 

2.  The  capacity  of  the  eyes  for  symmetrical  torsion  about 
a  sagittal  axis  increases  with  inclination  of  the  head  to  the 
right  or  left  shoulder.     This  increase  might  be  explained  as  a 
stimulation  by  the  compensatory  torsion  to  the  innervation 
of  the  muscles,  which  turn  the  eye  about  the  sagittal  axis. 

The  work  of  Wichodzew,  like  that  of  his  predecessors, 
still  leaves  the  question  of  the  sense  of  the  torsion  for  each 
individual  eye  still  undecided.  Besides  there  is  no  reason 
for  accepting  a  priori  that  the  movements  of  the  eyes  are  the 
same  when  the  fixation  point  is  kept  constant  and  the  head 
rotated,  as  when  the  head  is  kept  constant  and  the  fixation 
shifted. 

REPETITION  OF  PREVIOUS  EXPERIMENTS  BY  HERING  AND 

HELMHOLTZ 

Hering. — When  two  parallel  strips,  at  interocular  distance, 
are  looked  at  with  the  eyes  in  the  primary  position,  the  two 
strips  are  seen  as  three,  all  parallel.  But  as  soon  as  the 
fixation  point  approaches  nearer  than  infinity,  the  three 
break  into  four,  the  inner  one  making  two  images  not  parallel 
but  converging  at  the  top.  This  is  due  to  torsion  of  the 
eyeball,  which  increases  as  the  fixation  point  is  brought  nearer 
the  observer.  Likewise,  when  the  eyes  are  shifted  horizontally 
to  right  or  left,  the  convergence  of  the  two  middle  strips 
increases,  the  greater  the  shift  of  the  eyes.  The  purpose  of 
this  experiment  was  to  measure  the  amount  of  torsion  and 
to  measure  individual  differences  in  the  amount  of  torsion. 

Essentially  the  same  apparatus  and  procedure  was  used 
as  that  described  by  Hering  (18).  Likewise  the  results 
obtained  agree  with  Hering. 

I.  The  amount  of  torsion  of  the  eyes,  as  measured  by  the 
convergence  of  double  images  of  two  straight  lines,  increases 
directly  as  the  amount  of  convergence  of  the  eyes  increases, 
from  an  apparent  minimum  of  zero  to  the  maximum  with 
maximum  convergence. 


MILDRED  WRING 

2.  The  torsion  of  the  eye  increases  as  the  point  of  fixation 
is  directed  to  a  greater  distance  horizontally  either  left  or 
right  of  the  primary  position. 

3.  Keeping  the  fixation  point  constant,  a  bending  of  the 
head  forward  increases  the  amount  of  torsion;  raising  the 
head  decreases  the  amount  of  torsion. 

Helmholtz. — (a)  It  is  an  established  fact  that  we  do  not  see 
all  actual  straight  lines  as  straight.     In  fact,  if  we  look  at  a 

line  which  is  really  straight,  thus with  parallel 

lines  of  sight  and  a  card  held  in  front  of  the  nose  in  the  median 
plane  of  the  body  so  that  each  eye  sees  but  half  the  line,  it 
will  not  seem  straight  but  broken,  the  two  arms  converging 
thus  (allowing  for  much  exaggeration): 


If  now  by  some  device  we  compensate  for  this   apparent 
brokenness,  the  line  must  actually  be  made  thus: 


Now  if  the  eyes  are  converged  to  the  middle  point  of  the  line, 
where  the  card  meets  the  line,  the  line  which  had  been  made 
straight  apparently,  seems  broken  again  thus: 


And  to  compensate  for  this  additional  apparent  slant  of  the 
arms  of  the  line,  the  two  arms  of  the  actual  line  must  be  bent 
toward  one  another  downward,  still  more,  thus : 


The  apparent  convergence  of  the  two  arms  of  the  line  there- 
fore increases  as  we  pass  from  an  infinite  fixation  point  to 
one  very  near  the  eyes.  This  is  due  to  actual  torsion  of  the 
eyeball  about  its  sagittal  axis,  the  right  eye  turning  to  the 
left  and  the  left  eye  turning  to  the  right,  from  the  point  of 
view  of  the  observer. 


LAW  OF  EYE-MOVEMENTS  361 

The  apparatus,  based  on  Helmholtz's  idea  (17),  consisted 
of  a  strip  of  cardboard  10  X  1.5  cm.,  fastened  horizontally 
at  one  end  by  a  screw  to  a  vertical  screen  of  cardboard. 
Along  the  length  of  the  strip,  which  was  at  the  level  of  the 
eyes,  was  drawn  a  black  line  which  was  extended  through  the 
point  of  rotation  to  an  equal  horizontal  distance  on  the  screen. 
This  gave  a  horizontal  line  whose  apparent  brokenness  when 
fixated  under  certain  conditions,  with  a  vertical  screen  per- 
pendicular to  the  face  in  the  median  plane,  could  be  com- 
pensated for  by  rotating  the  strip,  and  so  give  a  measure  of 
the  rotation  of  the  eyes. 

The  results  indicate  that  with  any  given  fixation  point, 
there  is  a  torsion  of  the  eyes,  the  left  eye  to  the  right,  and 
the  right  eye  to  the  left,  from  the  point  of  view  of  the  observer 
himself.  This  result  agrees  with  that  obtained  in  Hering's 
double  image  experiment  above,  and  with  the  results  of  our 
original  experiment  below. 

Helmholtz. — (b)  It  has  been  shown  that  if  the  head  is 
held  in  the  primary  position,  and  a  colored  cross,  with  vertical 
and  horizontal  arms  (Listing's  figure),  be  located  on  a  vertical 
screen  with  the  intersection  point  at  the  middle  point  of  the 
line  joining  the  points  of  intersection  of  the  lines  of  sight  of 
the  eyes  with  the  screen,  the  shifting  of  the  eyes  to  any 
oblique  position  when  an  after-image  has  been  developed 
with  head  kept  fixed,  results  in  the  following  distortions  of 
the  arms  of  the  cross  (17): 

1.  Turning  the  eyes  to  the  right  above  or  left  below 

After-image  of  horizontal  arm  is  turned  to  the  left. 
After-image  of  vertical  arm  is  turned  to  the  right. 

2.  Turning  the  eyes  to  left  above  or  right  below 

After-image  of  horizontal  arm  is  turned  to  the 

right. 

After-image  of  vertical  arm  is  turned  to  the  left. 
According  to  Listing  and  corroborated  by  Helmholtz,  if 
the  eyes  are  turned  straight  above  or  below,  or  directly  to 
right  or  left,  the  after-images  of  horizontal  and  vertical  arms 
remain  horizontal  and  vertical. 

A  much   modified   form  of  Helmholtz's   apparatus   was 


362  MILDRED  WRING 

employed.  It  consisted  essentially  of  a  black  strip  rotating 
at  its  middle  point  against  a  white  screen.  The  after-image 
of  the  black  strip  could  be  directed  to  any  angle  of  any  quad- 
rant of  the  field  of  vision  at  a  fixed  distance  from  the  point  of 
rotation.  The  torsion  of  the  eye  as  determined  by  a  torsion 
of  the  after-image  was  measured  by  making  the  strip  parallel 
to  the  after-image,  and  reading  the  angle  of  torsion  directly. 
The  results  show  that  there  is  a  torsion  for  all  angles  of 
oblique  fixation,  for  the  right  eye  to  the  left  and  the  left  eye 
to  the  right,  from  the  point  of  view  of  the  observer.  This  is 
contrary  to  Listing,  Helmholtz  and  Sanford  in  that  they  deny 
torsion  for  the  horizontal  and  vertical,  and  Sanford  also  for 
45°.  The  results  show  too  that  the  method  of  after-images 
is  capable  of  showing  the  vertical  and  horizontal  torsion, 
which  Miss  Barnes  denied. 

EXPERIMENT 

Problem. — It  was  the  purpose  of  this  investigation  to  see 
whether  or  not  the  long-debated  question  of  torsion  of  the 
eyeball  around  the  sagittal  axis  could  be  settled  by  means  of 
a  very  carefully  made  apparatus  which  would  detect  any 
rotation  ordinarily  unobserved  by  other  methods  of  investi- 
gation. To  that  end,  recourse  was  had  to  the  principle  of 
the  method  of  Johannes  Miiller,  namely  the  observation  of  a 
fixed  line  upon  the  eye  when  that  eye  is  placed  in  different 
positions  in  the  field  of  regard.  The  fixed  line  of  the  eye  was 
one  of  the  radial  striae  of  the  iris.  A  description  of  the  ap- 
paratus, by  which  the  observation  was  made,  follows. 

Apparatus. — The  apparatus  consists  of  a  large,  vertical, 
semicirculcar  iron  arc,  one  meter  in  radius,  attached  solidly 
to  a  heavy  brick  chimney  in  the  dark  room  of  the  psycho- 
logical laboratory.  By  means  of  a  galvanometer,  it  was 
determined  that  the  vibration  of  the  chimney  is  so  slight  as 
not  to  overcome  the  inertia  of  the  apparatus.  The  iron  arc, 
which  was  turned  in  a  lathe  to  insure  smooth  surfaces,  is 
5  cm.  wide  and  2.5  cm.  thick,  and  is  graduated  into  arcs  of 
10°.  The  whole  arc  rotates  in  a  horizontal  direction  about 
its  extremities,  but  its  points  of  rotation  are  shifted  7.5  cm. 


LAW  OF  EYE-MOVEMENTS  363 

to  the  right  by  means  of  iron  plates,  to  accommodate  for  the 
eccentric  position  of  the  telescope  which  is  attached  to  the 
arc.  In  this  way,  the  vertical  cross-hair  of  the  telescope 
coincides  with  the  axis  of  the  arc.  The  upper  center  of  rota- 
tion has  on  it  a  horizontal,  circular  protractor,  7.5  cm.  in 
radius,  graduated  in  degrees,  to  measure  the  amount  of  rota- 
tion of  the  arc.  Attached  to  the  right  side  of  the  arc  is  a 
transit  telescope,  with  a  magnifying  power  of  34  times,  at  the 
distance  from  the  telescope  to  the  middle  point  of  the  arc. 
The  magnifying  power  was  determined  as  follows: 

At  a  distance  of  one  meter  from  the  telescope  a  meter 
stick  was  placed  in  a  vertical  position.  A  rider,  made  of  a 
narrowband  of  paper,  1.5  cm.  wide,  was  freely  movable  along 
the  length  of  the  meter  stick.  The  experimenter  then  looked 
at  the  rider  through  the  telescope  with  his  left  eye,  and 
directly  at  it  with  his  right  eye,  and  adjusted  the  rider,  so 
that  the  upper  edge  of  it,  magnified  in  the  telescope,  coincided 
with  the  upper  edge  of  it,  unmagnified,  as  seen  by  the  right 
eye.  With  the  images  of  the  left  and  right  eyes  thus  super- 
imposed, the  experimenter  observed  the  length  of  the  magni- 
fied rider  on  the  unmagnified  scale  of  the  meter  stick.  The 
left  eye  image  of  the  magnified  meter  stick  and  right  eye 
image  of  the  rider,  were  inhibited.  The  quotient  then  of  the 
magnified  length  of  the  rider  and  its  unmagnified  length 
represents  the  magnifying  power  of  the  telescope. 

Magnified  length  of  the  rider 51.5  cm. 

Unmagnified  length  of  rider 1.5  cm. 

Magnifying  power 51.5/1.5  =  34.3  times 

This  method  was  checked  by  the  method  of  focal  lengths. 
The  magnifying  power  =  /"//,  where  F  is  the  focal  length  of 
the  objective  and  /  the  focal  length  of  the  eye-piece.  Meas- 
urement of  the  focal  lengths  of  the  telescope  showed: 

Focal  length  objective,  F 26.5  cm. 

Focal  length  eye-piece,  / 8  cm. 

Magnifying  power 26.5/.S  =33.1  times 

The  telescope  of  the  apparatus  is  detachable  and  can  be 
slid  along  the  arc  to  any  desired  position  and  fastened  there. 
It  is  directed  inward,  perpendicular  to  the  arc. 


364  MILDRED  WRING 

Exactly  at  the  middle  point,  between  the  two  points  of 
rotation  of  the  arc,  suspended  by  means  of  an  iron  support, 
extending  out  from  the  brick  chimney,  is  a  small  brass  ring, 
3  cm.  in  diameter,  permanent  in  position,  at  which  the  obser- 
ver places  his  eye.  Also  from  this  same  support  is  attached 
a  head  rest.  It  is  made  of  an  iron  band  27  cm.  in  diameter 
surrounding  the  observer's  head  at  the  temples,  and  supported 
by  four  vertical  iron  strips  adjusted  in  length  vertically,  which 
at  a  distance  of  approximately  12  cm.  above  their  attachment 
to  the  iron  band,  bend  inward  to  a  common  point,  which  is 
the  center  of  support.  Screws,  with  flat  discs  at  their  ex- 
tremities, point  inward  through  the  iron  band,  which  are 
adjustable  to  accommodate  differences  in  size  of  head  of 
observers.  The  chin  is  supported  by  a  U-shaped  piece  of 
iron,  swinging  from  the  iron  band  so  that  it  hangs  about  in 
the  plane  of  the  brass  ring.  It  too  is  adjustable  vertically  by 
means  of  screws. 

The  head  rest  can  be  set  for  either  right  or  left  eye  position. 
The  observer  places  his  head  in  the  iron  band,  with  the  eye 
exactly  in  the  center  of  the  ring;  the  screws  are  tightened  to 
fit  the  head,  the  band  is  lowered  or  raised  to  accommodate 
his  height,  the  chin  rest  is  adjusted  likewise  and  then  the  head 
is  so  firmly  fixed  that  there  is  no  error  from  head  movements. 

The  telescope  is  attached  at  about  its  middle  point  to  the 
right  side  of  the  arc,  and  is  adjustable  in  three  planes,  ver- 
tically, horizontally,  and  circularly  about  its  long  axis.  It  is 
equipped  with  vertical  and  horizontal  cross  hairs  to  obtain 
accurate  settings.  A  vernier,  which  reads  to  o'.5  is  attached 
to  read  the  circular  rotation.  It  is  to  be  noticed  that  since  it 
is  necessary  practically  to  have  the  telescope  fastened  to  one 
side  of  the  arc,  the  points  of  rotation  of  the  arc  have  been 
shifted  an  equal  amount  in  the  same  direction.  By  dropping 
a  plumb  line  from  the  upper  point  of  rotation,  the  center  of 
rotation  of  the  arc  was  obtained,  at  which  point  the  center 
of  the  brass  ring  was  placed  and  marked,  by  two  perpendicu- 
larly intersecting  threads,  the  vertical  one  being  determined 
by  the  plumb  line.  The  telescope  was  then  set  in  a  horizontal 
position  at  the  zero  point  on  the  arc,  which  is  half  way  between 


LAW  OF  EYE-MOVEMENTS  365 

its  extremities,  and  the  intersection  of  the  cross-hairs  of  the 
telescope  coincides  with  the  intersection  of  the  threads  on  the 
brass  ring.  In  this  way  the  points  of  rotation  of  the  arc,  the 
center  of  the  brass  ring,  and  the  intersection  point  of  the 
cross-hairs  of  the  telescope  all  lie  in  a  plane,  parallel  to  the 
plane  of  the  arc.  With  a  new  position  of  the  telescope  on 
the  arc,  or  a  rotation  of  the  arc,  the  horizontal  and  vertical 
cross-hairs  of  the  telescope  still  coincided  with  the  horizontal 
and  cross-threads  passing  through  the  center  of  the  brass 
ring.  This  statement  must  be  modified.  Since  the  ap- 
paratus is  to  measure  rotation  in  a  vertical  plane,  perpendicu- 
lar to  the  plane  of  the  arc,  the  aim  was  so  to  construct  it  that, 
with  the  arc  and  telescope  in  a  given  position,  a  change  in 
position  of  the  arc,  or  of  the  telescope  on  the  arc,  the  vertical 
and  horizontal  cross-hairs  would  still  be  horizontal  and 
vertical.  By  making  the  axis  of  rotation  of  the  arc  absolutely 
vertical,  placing  the  center  of  the  brass  ring  precisely  at  the 
center  of  the  diameter  of  this  axis,  and  since  the  arc  was 
constructed  as  true  as  possible,  it  was  found  that  the  vertical 
and  horizontal  cross-hairs  remained  so  with  various  positions 
of  the  apparatus.  There  was  but  one  variation  in  the  ab- 
solute trueness  of  the  instrument.  When,  for  instance,  the 
arc  and  the  telescope  were  both  placed  in  the  zero  position 
and  the  vertical  cross-hairs  set  coincident  with  the  vertical 
cross-thread  of  the  brass  ring,  and  then  the  arc  was  rotated 
to  right,  the  thread  and  cross-hair,  though  both  remained 
vertical,  were  no  longer  coincident  but  were  laterally  dis- 
placed. Since  they  were  parallel,  by  adjusting  the  screw 
controlling  the  horizontal  shift  of  the  telescope,  they  could 
be  brought  into  concidence  again.  In  this  operation,  the 
cross-hair  was  not  rotated  from  its  vertical  position,  so  that 
whenever  a  rotation  of  the  cross-hair  was  necessary  in  the 
actual  experimentation,  to  cause  coincidence,  it  indicated,  not 
imperfection  in  the  apparatus,  but  a  rotation  of  the  line  which 
the  cross-hair  of  the  telescope  was  being  set  upon.  This  was 
the  intended  function  of  the  apparatus.  This  parallel  shift 
was  due  to  the  size  of  the  apparatus  and  the  high  magnifying 
power  of  the  telescope,  but  did  not  amount  at  a  maximum  to 


366  MILDRED  WRING 

more  than  two  or  three  turns  of  the  small  screw,  controlling 
the  horizontal  adjustment.  The  same  displacement  occurred 
in  a  vertical  direction  but  to  a  much  less  degree.  Two  electric 
lights  served  for  illumination.  One  light  was  attached  to  the 
arc  by  a  jointed  arm  and  could  be  slid  along  the  length  of  the 
arc.  It  was  used  to  illuminate  the  vernier;  the  other  was 
suspended  from  a  horizontal  arm  pivoted  to  the  top  of  the 
head  rest,  and  illuminated  the  eye  of  the  observer.  A  frosted 
globe  was  used  in  this  lamp,  to  lessen  the  fatigue  of  the  eye, 
and  to  give  a  more  diffuse  illumination. 

Procedure. — When  the  observer  was  seated  with  his  head 
in  the  head  rest  as  indicated  above,  the  arc  and  telescope 
were  placed  in  the  primary  or  zero  position;  that  is,  the  arc 
was  swung  to  a  zero  position  on  the  dial,  and  the  telescope 
set  horizontally  on  the  arc  at  its  middle  or  zero  point.  The 
observer  sat  with  his  left  eye  at  the  brass  ring  and  the  plane 
of  his  face  perpendicular  to  the  plane  of  the  arc,  so  that  looking 
straight  ahead  of  him,  his  eye  was  fixed  on  the  telescope.  A 
small  spot  of  white  paint  was  placed  at  the  middle  point  of 
the  objective  to  facilitate  fixation.  Next,  the  operator  ex- 
amined the  eye  through  the  telescope,  and  selected  on  the 
iris  a  line  or  set  of  two  points  upon  which  to  set  a  cross-hair 
of  the  telescope.  The  same  line  was  not  used  through  the 
whole  experiment,  inasmuch  as  it  might  have  an  unfavorable 
location  for  observation  with  certain  oblique  positions  of  the 
eye.  This  initial  reading  on  the  vernier  was  taken  as  the 
zero  reading.  Whenever  a  new  line  was  taken  on  the  iris, 
and  with  each  sitting  of  the  observer,  a  new  zero  was  taken. 

With  the  telescope  at  zero  position  still,  the  arc  was  swung 
15°  to  the  right.  The  head  of  the  observer  was  not  moved; 
in  fact,  its  position  was  kept  constant  throughout  a  sitting. 
The  eye,  however,  was  turned  horizontally  in  its  orbit  to  the 
new  position  of  the  telescope  and  fixed  again  on  the  white 
spot.  The  operator  reexamined  the  eye,  set  the  cross-hair 
on  the  experimental  line  of  the  iris,  and  read  the  vernier. 
The  difference  between  the  first  and  second  readings  repre- 
sented the  angle  of  torsion  of  the  eyeball.  Similarly  angles  of 
torsion  were  obtained  for  15°  to  the  left  and  30°  to  both  right 


LAW  OF  EYE-MOVEMENTS  367 

and  left.  The  arc  was  then  returned  to  the  zero  position  of 
the  dial,  and  the  telescope  was  then  moved  along  the  arc  to  a 
position  15°  above  the  zero,  or  middle  point  of  the  arc.  The 
reading  was  taken  here,  and  again  the  arc  was  swung  15°  to 
the  left  and  to  the  right  and  also  30°  to  the  left  and  to  the  right, 
and  readings  taken.  The  difference  of  the  readings  in  any 
position  from  the  reading  of  the  zero,  represented  the  torsion 
for  that  position.  Observations  were  made  upon  both  right 
and  left  eyes.  As  summary  of  the  positions  of  the  eye  in 
which  readings  were  taken  is  as  follows: 

Telescope.  Arc. 

I.  50°  above 50°  left— if  left— zero— if  right— 30°  right 

II.  75°  above 50°  left — 75°  left — zero — 75°  right — 30°  right 

III.  Primary  position 30°  left — 75°  left — zero — 75°  right — 30°  right 

IV.  75°  below 30°  left — 75°  left — zero — 75°  right — 30°  right 

V.  30°  below 30°  left— if  left— zero— if  right— 30°  right 

In  spite  of  the  accuracy  of  the  instrument,  certain  un- 
avoidable errors  arose  in  taking  data.  These  were: 

1.  Certain  reflex  pupillary  expansions   and  contractions 
even  with  a  constant  intensity  of  illumination.     This  changed 
the  size  of  the  iris  and  therefore  the  direction  of  the  line  set 
upon,  in  spite  of  every  care  to  have  the  line  a  true  radius  of  the 
iris. 

2.  Nystagmoid  movements  of  the  eyeball,  entirely  involun- 
tary, due  to  reflex  contractions  of  the  eye-muscles,  as  a  result 
of  continued  fixation. 

3.  A  marked  change  in  the  pattern  of  the  iris,  owing  to 
torsion.     Sometimes  it  was  difficult,  in  a  new  position  of  the 
telescope,  to  recognize  the  line  to  be  set  upon,  owing  to  certain 
twistings  in  the  pattern,  which,  while  not  very  extended,  yet 
interfered  markedly  with  an  accurate  setting  of  the  cross-hair. 

Results. — I.  Each  number  in  Table  I.  (a)  and  (b)  repre- 
sents the  average  of  five  observations  in  that  position. 

2.  In  Table  I.,  the  column  headed  "Position,"  the  sign  + 
before  a  parallel  indicates  a  position  of  the  telescope  above 
the  zero  parallel  on  the  arc,  the  sign  — ,  a  position  below  the 
zero  parallel  on  the  arc;  the  sign  +  before  an  angle  in  the 
subgroup  (  +  30°,  +15°,  o,  —15°,  —30°)  underneath  a  parallel, 
indicates  a  position  of  the  arc  to  the  right  of  the  zero  on  the 


M  t^oo  ^^o       ^  *•;  "f*  *>  "t"       9^9      *?  9s 
°o  °o  °o  °o  °o        °o  °o  °o  °o  °o        °o°o      °o°o 


9  * 


N    M  00  VO 


HI     M     M     M 

°o  *b  °o  °o  °o 


M     C*     HI     HI     C* 

°o  °o  °o  °o 


oo  ON  >J->  O  VO 


Oo0o0o0o°o 


vo  O 


*     * 


b*  TJ-OO  O  O 


1-1  LD  rj-  -^- 


TJ-  "*•      ON         qvqoNoo         -^vq  q  "f  -* 

N   ••$•       O  ON         OO  M   N  "t^^O  t/i  tr>  vi  Q 

LO        Q   HI  10  ur>        N 


C»     Tj-VO     N-«1-  NCOMMHI  OW  OO  r*^Tj-O»-<'«!j-  ONLTiN 

1  ++  1  1     +++  II     +  1    ++     1  +  1  1  1     +++++ 


OO  OO  VO   -^-  O  c^O^VOO  OOVO         OO 


"J-00   O  00  00 


++  1  i  i     +  1  i  i  i      ii     ii        i  i  i  i      i  i  i  i  + 


OOOOON        NOO      qo 


voTj- 


ooooo 

N  ,prp 


O 

N   HI         O   O  VO   O 

I      I         ++  M 


1      1     1    +  + 


vb  *lr)Vi*bN*b 
Oo0o0o°o0o       Oo0oo0o°o       °o°o     °0°o       Oo0o0o0o°o       Oo0o0o0o°o 


°0  °0  °0  °0  °0     °0  °0  °0  °0  °0     °0  0    00     OOOOO     0  °0  0  °0  °0 


4^vMOOMi/->         vot^-^voco          NOOr^t^ 

HITt-l-HCOLO  MHlOc^M  l_,Mr<N 


^  9 

CO  *to 


++  1  i        i  i  i  i  i 


c^NN^l-Tj-  ONOOOOLo 

I      I      I      I      I  ++   I      I     I 


HHTj- 

ooooo 


i-<  - 

HHC^Tj-ThU 

ooooo 


b  oo 

MHH  WHH 

ooOoo 


oooo 


00000**  «/i 

lOTj-N-^-hH 

ooooo 


++++  1      iiii        ii     ii          i  i  +         i++ 


oo  oo  q  *o  N         q  ONVO  oo  •«*•       oo  N      vq  ^        -<j-oq  q  q  q 

*O  *ir>*O  ^C^OO  *O  "l^*ON*'''f*Hi  OO  *O        %J-">t>          *|O"N  "V»VO  ^Q  OO  "HI    u->VO    f> 

O 


O      O       VJ  o      O 


ooooo 


ooooo 


i  i  M       +++  M      I+M      IIM+         iii 


t-iOOOOO  t-iOooOO  l-iOOOOO  £oOOOO  S-iOOO 

O^rOHi          i-c    «<-)      o,  c<-j  HI          HI    r^>      CXi  m  HH          HicoOnCOHi          Mc^D<r<^Hi          HH 

I  I  ° ++    I  I  <k++    II 


LAW  OF  EYE-MOVEMENTS 


369 


dial,  the  sign  —  before  an  angle  indicates  a  position  to  the 


left. 


parallel. 

indicates  a  position  where  the 


For  instance  __     o 

telescope  has  been  placed  15°  above  the  zero  or  middle  point 
of  the  arc,  and  the  arc  rotated  30°  to  the  left  of  the  zero  on 
the  dial.  These  signs  are  taken  from  the  point  of  view  of 
the  experimenter,  who  looks  through  the  telescope. 

3.  In  the  column  headed  "Torsion,"  the  sign  +  in- 
dicates torsion  of  the  eye  to  the  right  from  the  point  of  view 
of  the  experimenter;  the  sign  —  indicates  torsion  to  the  left. 

Conclusion.  —  I.  The  results  are  to  some  extent  irregular, 
both  as  to  the  amount  of  torsion  and  direction. 

(a)  As  the  eye  travels  from  the  primary  position  to  scu- 
cessively  more  oblique  positions,  there  seems  to  be  a  tendency 
for  the  angle  of  torsion  to  increase,  but  some  exceptions  occur. 
Likewise  a  movement  of  one  eye  to  a  given  position  does  not 
give  the  same  amount  of  torsion  as  the  movement  of  the  other 
eye  through  the  same  angle.  Similarly,  the  sense  of  the  torsion 
does  not  remain  constant  for  one  eye  in  all  cases,  and  the 
torsions   for  the   two  eyes   for  movements   through   similar 
angles  is  not  always  opposite  or  always  the  same. 

(b)  There  is  a  predominance  of  torsion  to  the  right  of  the 
right  eye,  and  to  the  left  of  the  left  eye,  from  the  standpoint 
of  the  experimenter.     Out  of  24  positions  for  each  eye  away 
from  the  primary  position,   for  each  observer  we  find  the 
following: 


Torsion  of  Right  Eye 

Torsion  of  Left  Eye 

To  the  Left 

To  the  Right 

To  the  Left 

To  the  Right 

I 

2 

3 

9  cases 
20  cases 
10  cases 

15  cases 
4  cases 
14  cases 

19  cases 
17  cases 
20  cases 

5  cases 
7  cases 
4  cases 

It  will  be  seen  that  for  the  left  eye,  the  great  predominance  of 
torsion  is  to  the  left  for  all  three  observers,  and  that  for  the 
right  eye,  the  predominance  is  to  the  right  for  two  of  the  three 
observers. 

II.  The  most  definite  conclusions  consist  then  mainly  in 
the  two  following  observations: 


37°  MILDRED  WRING 

(a)  A  tendency  for  the  torsion  to  increase  as   the  eye 
passes  from  the  primary  position  to  successively  more  oblique 
positions,   including  horizontal,   vertical   and  45°   meridian. 

(b)  A  predominance  of  torsion  of  the  left  eye  to  the  left, 
and  of  the  right  eye  to  the  right,  from  the  point  of  view  of  the 
experimenter. 

LITERATURE 

1.  JOHANNES  MULLER.     Zur  vergleichenden  Physiologic  des  Gesichtssinns,    1826, 

p.  254. 

2.  ALEXANDER  HUECK.     Die  Achsendrehung  des  Auges,  1838. 

3.  A.  BUROW.     Beitrage  zur  Physiologic  des  Auges,  1841,  p.  8. 

4.  A.  W.  VOLKMANN.    Wagner's  Handworterbuch  der  Physiologic,  1846,  Band  3, 

Abt.  I.,  p.  273. 

5.  THEODOR  RUETE.     Lehrbuch  der  Ophthalmologie,  1846,  p.  14. 

6.  G.  VALENTIN.     Lehrbuch  der  Physiologic,  II.  (2),  1846,  p.  32. 

7.  F.  C.  BONDERS.     Hollandische  Beitrage  zu  dem  anat.  und  phys.  Wissenschaften, 

I.,  1848,  pp.  105-145,  384-386. 

8.  A.  FICK.     Ztschr.  fur  rat.  Medizin,  IV.,  1854,  p.  101. 

9.  G.  MEISSNER.     Beitrage  zur  Physiologic  des  Sehorgans,  1854. 

10.  G.  MEISSNER.     Graefe's  Arch.f.  Ophthalmologie,  II.  (i),  1855,  pp.  1-123. 

11.  THEODOR  RUETE.     Lehrbuch  der  Ophthalmologie,  I.,  1855,  p.  37. 

12.  A.  FICK.     Moleschott's  Untersuchungen  z.  Naturlehre  der  Menschen,  V.,  1858, 

P-  193- 

13.  G.  MEISSNER.     Ztschr.  fur  rat.  Med.  (3),  VIII.,  1860,  p.  I. 

14.  W.  WUNDT.     Archiv  fur  Ophthalmologie,  VIII.  (2),  1862,  pp.  16-17. 

15.  H.  HELMHOLTZ.     Archiv  fur  Ophthalmologie,  IX.,  1863,  pp.  153-214. 

16.  A.  W.  VOLKMANN.    Physiologische  Unters.  im  Gebiete  der  Optik  (2),  1864,  pp. 

199-240. 

17.  H.  HELMHOLTZ.    Handbuch  der  Physiologischen  Optik,  Ed.  2,  1866,  pp.  613-669. 

1 8.  EWALD  HERING.     Die  Lehre  vom  Binocularem  Sehen,  1868,  pp.  83-92. 

19.  H.  AUBERT.    Graefe-Saemische  Handbudi  der  gesammten  Augenheilkunde,  II. 

(2),  1876. 

20.  JOSEPH  LE  CONTE.     Sight,  1881,  pp.  185-212. 

21.  A.  MEINONG.     Ztschr.  fur  Psych,  u.  Physiol,  XVII.,  1898,  p.  161. 

22.  E.  SANFORD.     Experimental  Psychology,  Appendix,  1898. 

23.  BERNICE  BARNES.     American  J.  Psych.,  Vol.  16,  1905,  p.  199. 

24.  A.  WICHODZEW.     Ztschr.  f.  Sinnesphysiologie,  II.,  1912,  p.  394. 


VARIABILITY^  IN  PERFORMANCE  DURING  BRIEF 
PERIODS  OF  WORK 

BY  A.  T.  POFFENBERGER,  JR.,  and  GLADYS  G.  TALLMAN 

Columbia  University 

Numerous  researches  have  been  carried  on  to  show  the 
effects  of  working  for  long  periods  of  time  or  with  extremely 
difficult  tasks.  The  effects,  known  as  fatigue,  may  show 
themselves  in  a  decrease  in  the  quantity  or  quality  of  the 
product.  Analogous  changes  in  the  character  of  the  per- 
formance, which  have  scarcely  warranted  the  name  of  fatigue 
as  the  term  is  ordinarily  used,  appear  in  extremely  brief 
periods  of  mental  work.  For  instance,  Professor  Woodworth 
in  a  recent  paper,1  showed  some  changes  in  speed  of  perform- 
ance which  take  place  during  the  naming  of  only  ten  simple 
colors.  The  present  report  contains  a  brief  series  of  records 
showing  a  variation  in  performance  in  tasks,  none  of  which 
lasted  as  long  as  one  minute. 

In  some  of  the  previous  work  on  fatigue  one  finds  references 
to  the  effects  of  brief  work  periods,  although  in  few  of  them 
did  the  matter  receive  much  attention.  Voss2  made  detailed 
studies  of  an  hour's  work  in  addition,  taking  time  for  each 
separate  problem.  He  concludes  that  practice  tends  to 
increase  the  number  of  rapid  additions  and  fatigue  the 
number  of  slow  additions.  The  procedure  followed  made  it 
impossible  to  separate  the  practice  and  fatigue  effects  for 
the  short  periods  measured.  Hylan  and  Kraepelin3  measured 
the  variation  in  adding  one-place  numbers  in  five-minute 
periods.  They  concluded  that  mental  work  lasting  for  only 

1  An  unpublished  paper  read  before  the  New  York  Branch  of  the  American 
Psychological  Association  at  Princeton,  N.  J.,  Feb.  23,  1914,  entitled  'The  Work  Curve 
for  Short  Periods  of  Intense  Application.' 

2  George  von  Voss,  'Ueber  die  Schwankungen  der  geistigen  Arbeitsleitung,'  Psychol. 
Arbeit.,  Vol.  2,  pp.  399~449- 

3  Hylan,  J.  P.,  and  Kraepelin,  E.,  'Ueber  die  Wirkung  kurzer  Arbeitszeiten,' 
Psychol.  Arbeit.,  Vol.  4,  pp.  454-495. 

371 


372  A.  T.  POFFENBERGER  AND  G.  TOLLMAN 

five  minutes  produced  an  appreciable  amount  of  practice  and 
fatigue.  The  ratio  of  the  two  factors  differed  for  different 
individuals.  In  the  work  of  Arai1  on  the  multiplication  of  a 
series  of  two  four-place  numbers  the  time  for  each  problem 
was  measured.  In  the  author's  conclusions  (p.  93)  we  note 
that  "the  difference  between  the  time  taken  for  one  example 
and  that  taken  for  another  is  greater  in  the  second  half  than 
in  the  first  half  of  the  curve.  This  fact  together  with  the 
evidence  of  introspection  of  the  subject  suggests  that  fatigue 
not  only  causes  decrease  of  efficiency,  but  also  loss  of  the 
subject's  control  over  herself.  For  this  reason  the  subject 
tends  to  occasionally  relax  her  original  standard  of  effort." 
In  this  experiment  the  subject  had  passed  the  stage  where 
practice  was  an  important  factor. 

In  the  experiment  to  be  reported  two  time  records  were 
taken  for  each  task,  one  at  the  completion  of  the  first  half 
and  the  other  at  the  end  of  the  task.  The  time  was  taken 
with  a  stop  watch  in  units  of  one  fifth  of  a  second.  From 
these  two  records  one  may  compare  the  performance  during 
the  first  and  second  halves  of  the  work.  Speed  was  the  only 
variable  factor,  for  the  experimenter  announced  all  errors  and 
these  were  corrected  by  the  subject.  It  is  to  be  noted  further 
that  the  subjects  were  trained  in  all  of  the  tests,  and  that 
practice  effect  was  thus  practically  eliminated.  If  this  were 
not  the  case  it  is  quite  possible  that  the  improvement  by 
practice  within  a  single  test  might  have  clouded  the  results. 
An  intensive  study  was  made  upon  two  subjects,  each  test 
being  repeated  from  60  to  70  times  after  the  preliminary 
practice. 

Four  tests  were  used,  two  of  them  being  taken  from  the 
Woodworth  and  Wells2  monograph  on  association  tests. 
These  were  the  color  naming  test  and  the  number  checking 
test,  called  the  cancellation  test  in  this  report.  Only  half 
of  the  regular  number  checking  blank  was  used  for  one  test, 
so  that  the  halves  measured  were  really  fourths  of  the  whole 

1Arai,  Tsuru,  'Mental  Fatigue,'  Teachers  College,  Columbia  University  Con- 
tributions to  Education,  No.  54,  1912. 

*  Woodworth,  R.  S.  and  Wells,  F.  L.,  'Association  Tests,'  Psychological  Mono- 
graph, 1911,  No.  57. 


VARIABILITY  IN  PERFORMANCE  373 

blank.  The  numbers  3  and  5  were  used  alternately  for  can- 
cellation. The  third  test  was  the  opposites  test  and  con- 
sisted of  50  words,  the  opposites  of  which  were  to  be  named. 
They  were  about  equal  in  difficulty  to  the  moderately  difficult 
series  of  Woodworth  and  Wells.  The  fourth  test  was  the 
addition  test  and  consisted  in  adding  17  to  each  of  50  two- 
place  numbers,  ranging  from  20  to  80  with  all  of  the  com- 
binations containing  zero  being  omitted.  In  every  case  the 
test  material  was  divided  into  two  parts  by  a  line,  so  that  the 
subject  could  see  the  limits  of  the  first  and  second  half.  The 
subject's  work,  however,  was  continuous  from  the  beginning 
to  the  end  of  the  test. 

The  tests  were  repeated  approximately  five  times  each 
day,  with  an  interval  of  several  hours  between  any  two,  thus 
avoiding  cumulative  fatigue.  All  of  these  tests  involve  the 
process  of  association  and  the  connection  between  situation 
and  response  was  in  each  case  partially  established  in  the 
preliminary  tests.  It  is  to  be  remembered  that  the  test 
material  was  always  the  same,  the  only  difference  being  the 
order  in  which  the  stimuli  were  presented.  There  were  four 
possible  changes  of  order  in  the  color  naming  test,  by  rotating 
the  color  blank  90  degrees  at  each  trial;  four  in  the  number 
checking  test,  by  using  different  halves  of  the  test  and  either 
one  of  the  numbers  3  or  5  for  cancellation;  ten  in  the  opposites 
and  addition  tests  by  means  of  ten  cards  containing  the  same 
numbers  in  a  random  position  on  each. 

The  data  of  the  experiment  are  presented  in  the  accom- 
panying table.  The  third  column  of  the  table  shows  the 
number  of  cases  from  which  the  calculations  are  made  for 
each  test.  The  fourth  column  gives  the  average  speed  for 
the  first  half  of  the  test  in  terms  of  seconds.  The  fifth  column 
gives  the  gross  differences  between  the  first  and  second  halves. 
In  every  case  the  first  half  was  subtracted  from  the  second 
half,  so  that  the  absence  of  minus  signs  indicates  greater  speed 
in  the  first  half.  The  sixth  column  shows  the  reliability  of 
these  differences  in  terms  of  the  probable  error  of  the  differ- 
ence. The  seventh  column  shows  the  difference  in  terms  of 
per  cent,  of  the  time  of  the  first  half.  The  column  of  gross 


374 


A.  T.  POFFENBERGER  AND  G.  TALLMAN 


differences  shows  that  in  every  test  and  for  both  subjects  the 
first  half  is  quicker  than  the  second  half,  while  the  following 

RELATION  BETWEEN  SPEED  OF  PERFORMANCE  IN  THE  FIRST  AND  SECOND  HALF  OF 

THE  TESTS. 

(In  every  case  the  first  half  is  subtracted  from  the  second  half,  so  that  absence  of 
minus  signs  indicates  that  the  first  half  is  faster.) 


Test 

Subject 

No.  Cases 

ist  Half 

Gross  Diff. 

P.  E. 

Per  Cent. 
Diff. 

Opposites 

T 

CQ 

16.2 

O  I 

II  7 

Addition 

P 
T 

6? 

7O 

12.9 

28  t: 

•7 

•7 

O.I 
O  1 

13-2 

ii  6 

Color  Naming  

P 
T 

% 

18.4 
2O.O 

.1 
.0 

0.2 
O.2 

6.0 

o.r 

Cancellation  

P 
T 

$ 

61 

17.0 
2^.8 

.0 

2.2 

O.2 

O.2 

5-9 

0.2 

P 

60 

20.3 

0.7 

0.2 

34 

column  shows  that  the  differences  are  reliable.  The  data 
when  examined  in  detail  and  when  treated  in  several  other 
ways,  show  only  one  interesting  exception.  When  the  tests 
are  grouped  according  to  the  time  of  day  they  were  performed, 
namely  9.30  A.  M.,  1.30,  3.30  and  5.30  P.  M.,  it  appears  that 
in  the  case  of  the  cancellation  test  and  at  the  9.30  period  both 
subjects  were  on  the  average  slower  in  the  first  half  than  in 
the  second  half  of  the  test.  No  explanation  for  this  peculiar 
difference  is  suggested.  The  data  treated  in  this  fashion 
show  only  one  other  case  where  the  first  half  is  slower  and  here 
the  negative  quantity  is  less  than  its  probable  error. 

The  last  column  in  the  table  shows  the  per  cent,  of  differ- 
ence in  favor  of  the  first  half.  It  should  be  considered  merely 
as  indicating  differences  between  halves  in  the  tests,  for  only 
two  subjects  are  not  sufficient  to  establish  differences  of  this 
type  among  the  tests  used.  If  the  tests  are  grouped,  one  can 
say  roughly  that  in  speed  of  performance  subject  T  was  about 
10  per  cent,  less  efficient,  and  subject  P  about  7  per  cent,  less 
efficient  in  the  second  thirty  seconds  of  the  work  than  in 
the  first  thirty  seconds. 

A  series  of  ten  questions  was  given  to  each  subject  at 
the  end  of  the  series  of  tests  to  determine  if  introspection 
could  throw  any  light  upon  the  results.  For  instance,  the 


VARIABILITY  IN  PERFORMANCE  375 

subjects  were  asked  if  they  noticed  any  difference  in  speed, 
ease  of  performance,  number  of  errors,  etc.,  in  different  parts 
of  the  tests,  and  if  so  whether  they  could  account  for  such 
changes.  A  separate  series  of  questions  was  given  for  each  of 
the  four  tests.  Both  subjects  felt  that  they  made  more  errors, 
and  hesitated  more  in  the  second  half  than  in  the  first.  In 
both  subjects  there  was  consciousness  of  being  slow  with  a 
feeling  of  inability  to  make  the  mind  work  any  faster.  The 
speed  was  probably  judged  by  the  number  of  errors  and  hesita- 
tions that  occurred,  according  to  the  answers  to  some  of  the 
questions.  The  mistakes  were  attributed  not  so  much  to 
lapses  of  attention  as  to  just  getting  tired.  Neither  subject 
reached  the  stage,  during  the  course  of  the  experiment,  where 
the  task  became  automatic,  i.  <?.,  where  he  no  longer  felt  as 
though  he  were  putting  forth  a  great  deal  of  energy. 

In  drawing  conclusions  from  these  records  it  is  necessary 
to  keep  the  specific  conditions  in  mind:  (i)  The  test  material 
was  always  the  same,  except  for  the  difference  in  arrangement. 
(2)  The  process  involved  in  the  reaction  to  the  situations  was 
mainly  the  recall  of  previously  formed  associations.  (Formed 
or  at  least  strengthened  during  the  preliminary  tests.)  (3) 
There  was  practically  no  practice  effect  within  any  test,  on 
account  of  the  preliminary  tests,  and  the  use  of  the  same  ma- 
terial throughout.  This  is  a  condition  not  found  in  mental 
fatigue  tests  where  the  records  are  made  at  frequent  intervals. 
(4)  The  subjects  worked  at  their  best  speed,  with  no  rest  period 
between  the  first  and  second  halves  of  the  test.  (5)  There 
was  no  rest  interval  between  the  performance  of  separate 
items  of  the  tests,  such  as  the  relaxation  which  may  take 
place  at  the  end  of  each  addition  or  multiplication  problem 
usually  employed  for  fatigue  work,  especially  where  the  time 
required  for  each  problem  is  the  unit  of  measure. 

This  falling  off  in  performance  within  such  a  short  period 
in  the  case  of  two  subjects  in  the  mental  tests  described, 
suggests  the  importance  of  devising  simple  mental  tests, 
which  shall  approximate  the  classical  ergograph  test  as 
performed  upon  a  trained  subject,  in  its  simplicity,  forced 
regularity  of  response  (e.  g.,  metronome  beat  in  the  ergograph 


376  A.  T.  POFFENBERGER  AND  G.  T4LLM4N 

test),  and  in  the  complete  record  obtained.  For  it  is  probable 
that  mental  fatigue  is  not  so  rare  as  is  sometimes  supposed, 
but  that  the  repair  process  is  so  rapid  compared  with  muscle 
repair,  that  as  work  is  usually  done,  the  loss  may  be  com- 
pensated for  during  brief  intervals  of  relaxation. 


THE  STANDARDIZATION  OF  KNOX'S  CUBE  TEST 

BY  RUDOLF  PINTNER 

Ohio  State  University 

This  paper  deals  with  the  results  obtained  with  KnoxV 
Cube  Test,  one  of  the  performance  tests  used  by  him  for  the 
mental  classification  of  immigrants  at  Ellis  Island.  The  test 
has  been  given  to  867  normal  children  and  a  few  adults,  and 
to  463  feeble-minded  individuals.  An  attempt  has  been  made 
to  enlarge  the  scope  of  the  test  and  to  standardize  it  a  little 
more  adequately.  The  test  appeared  to  me,  after  first  seeing 
it  applied,  to  be  an  excellent  one  in  many  ways.  Without 
attempting  to  enter  into  a  useless  discussion  as  to  the  actual 
mental  processes  involved,  we  may  say  in  a  general  way  that 
it  depends  largely  upon  imitation,  at  the  same  time  affording 
every  opportunity  for  other  factors  involving  intelligence  to 
assert  themselves. 

The  Method  of  Procedure. — Five  blocks  are  required.  The 
Binet  black  cubes  were  used,  but  any  other  cubes  of  about  the 
same  size  would  be  satisfactory,  provided  they  are  all  of  the 
same  color.  Four  of  these  are  placed  on  the  table  in  front  of 
the  subject  at  a  distance  of  about  two  inches  apart.  The 
examiner  holds  the  fifth  cube  in  his  hand.  He  says  to  the 
subject:  "Watch  carefully,  and  then  do  as  I  do."  He  then 
taps  the  blocks  with  the  fifth  cube  in  a  certain  definite  order 
and  at  a  certain  definite  rate  (about  one  tap  per  second), 
always  beginning  with  the  cube  at  the  child's  left  or  the  ex- 
aminer's right  if  he  is  facing  the  child.  He  then  lays  the  fifth 
cube  down  in  front  of  the  child  equidistant  between  the  third 
and  fourth  cube,  but  nearer  to  the  child,  and  says:  "Do  that." 

These  oral  directions,  "Watch  carefully  and  then  do  as  I 
do,"  and  "Do  that,"  were  given  to  almost  all  of  our  subjects. 

1  Knox,  Howard  A.,  The  Journal  of  the  American  Medical  Association,  March  7, 
1914,  Vol.  LXIL,  pp.  741-747- 

377 


378 


RUDOLF  P1NTNER 


I  do  not  believe  this  is  necessary  and  I  am  sure  exactly  the 
same  results  would  have  been  obtained  by  saying  nothing. 
This  is  borne  out  by  some  of  the  subjects  who  did  not  under- 
stand English  and  by  deaf  children  and  by  some  children  who 
seemed  too  young  to  understand  such  verbal  directions.  In 
these  cases  all  that  was  necessary  was  to  make  some  gesture 
indicating  that  the  fifth  block  was  to  be  picked  up  and  the 
others  to  be  touched. 

The  first  line  of  the  test,  as  will  be  noted  presently,  is  so 
simple  that  even  although  the  subject  does  not  know  while 
watching  the  examiner  that  he  will  be  required  to  do  the  same 
thing,  he  can  easily  remember  and  imitate  what  has  been 
done.  There  are  of  course  innumerable  combinations  in 
which  one  can  tap  four  blocks,  if  one  is  not  limited  to  touching 
each  cube  only  once.  If  we  number  the  blocks  the  different 
combinations  will  be  readily  understood,  and  the  following 
diagram  should  make  absolutely  clear  their  position  with 
regard  to  the  subject  and  the  examiner  (if  he  is  facing  the 
subject). 

Subject 


Examiner 

The  following  twelve  combinations  or  lines  have  been  used 
in  this  experiment.  Number  I  always  refers  to  the  block  on 
the  left-hand  side  of  the  child. 


A  lit 

ie  

[234. 

X 

] 

[2343 

Y 

2  3   4.  2 

ff 

•$24, 

c 

41   2 

r> 

A    2   •? 

F 

32  4,  •? 

F 

4-224. 

G 



•2124. 

H 

4.  -2    I   2  4. 

J 



•2    2  4   I    3 

1 

4  2   3  4.   I 

STANDARDIZATION  OF  TESTS  379 

Knox  uses  only  five  lines.  The  advantages  of  my  extension  to 
twelve  will,  1  think,  be  apparent  in  the  light  of  the  results. 
The  lines  are  taken  up  in  the  order  of  sequence  in  which  they 
appear  above.  It  will  be  noted  that  this  is  roughly  an  order 
of  increasing  difficulty.  A  line  is  never  repeated,  not  even  if 
the  subject  begins  any  line,  the  A  line  included,  at  the 
wrong  end.  This  is  an  error  that  we  have  marked  W.E. 
(wrong  end)  and  will  discuss  later.  The  subject  is  never 
corrected,  but  is  allowed  to  do  a  line  exactly  as  he  chooses. 
No  hint  must  be  given  the  subject  as  to  whether  he  is  doing  a 
line  right  or  wrong.  Some  children  pause  and  look  up  at  the 
examiner  waiting  for  a  cue  as  to  the  next  move.  The  subject 
is  encouraged  to  do  his  best  and  is  told  that  he  is  doing  well, 
regardless  of  his  actual  accomplishment.  Each  line  is  marked 
plus  or  minus  according  as  the  subject  does  it  correctly  or 
incorrectly.  If  the  subject  corrects  a  wrong  move,  thereby 
making  the  whole  line  correct,  he  is  credited  with  a  plus. 

The  numbers  of  the  moves  must  not  be  shown  to  the  child 
and  the  examiner  must  not  count  aloud  or  indicate  in  any  way 
that  he  is  counting.  This  precaution  is  very  necessary  with 
intelligent  older  children  and  with  adults.  Nothing  in  fact 
is  said  about  counting  and  the  subject  is  left  free  to  pursue 
that  method  if  he  has  the  intelligence  to  think  of  it.  This 
will  of  course  show  in  a  greater  number  of  lines  passed  cor- 
rectly and  therefore  the  subject  receives  credit  for  his  in- 
telligent adaptation.  We  asked  every  subject  who  did  very 
well,  i.  e.,  succeeded  in  almost  all  of  the  lines,  how  he  did  it. 
Some  replied  at  once  that  they  were  counting.  Others  were 
uncertain.  We  suggested  to  the  latter  that  they  were  count- 
ing and  if  they  assented,  we  asked  them  and  also  those  who 
told  us  they  were  counting,  to  count  aloud  while  we  repeated 
one  of  the  longer  lines  or  a  new  combination  of  moves.  The 
examiner  can  then  tell  whether  it  is  the  kind  of  counting 
that  will  help  in  remembering  the  moves.  Some  children 
who  said  they  remembered  the  moves  by  counting  were 
found  simply  to  be  saying  to  themselves,  one,  two,  three, 
four,  etc.,  every  time.  This,  to  be  sure,  would  help  them  to 


380  RUDOLF  PINTNER 

remember  the  number  of  moves  but  would  not  help  them  to 
remember  the  position  of  the  blocks  touched.  The  other  kind 
of  counting  which  assigns  constant  numbers  or  letters  to 
each  block  was  found  to  be  very  rare.  We  found  it  only  in 
about  twenty  cases  out  of  our  867  individuals.  This  kind  of 
counting  did  not  seem  to  occur  to  the  majority  of  adults  who 
were  tested  by  us. 

In  many  respects  this  method  of  giving  the  test  differs 
radically  from  that  of  Knox,  as  far  as  can  be  determined  from 
the  very  brief  description  of  the  test  in  the  article  cited  above. 
Knox  allows  a  repetition  of  a  line  on  the  part  of  the  examiner, 
in  contrast  to  my  procedure  where  a  line  is  never  repeated. 
For  the  first  five  of  his  lines  he  gives  three  trials  '  if  neces- 
sary,' and  for  his  last  and  most  difficult  line  involving  six 
moves  he  allows  five  trials.  If  the  subject  fails  he  is  evidently 
shown  the  moves  over  again  to  the  extent  of  three  or  five  times 
if  necessary.  The  drawback  of  this  method  seems  to  lie  in 
the  fact  that  a  varying  number  of  repetitions  of  any  line  will 
cause  unequal  practice  effect.  For  example,  the  subject  that 
fails  twice  on  the  second  line  and  passes  on  the  third  trial  will 
have  made  up  to  that  point  four  responses  to  the  test,  whereas 
the  subject  that  passes  the  second  line  at  the  first  trial  will 
have  made  only  two  responses.  Each  will  then  start  the 
third  line  with  different  degrees  of  familiarity  with  the  situa- 
tion, and  it  is  possible  that  the  first  subject  may  have  gained 
an  unfair  advantage  over  the  second,  even  although  the  first 
subject  is  not  doing  as  well  as  the  second  as  shown  by  his 
failures.  A  fair  comparison  of  their  performances  in  the 
succeeding  lines  will  nevertheless  be  impossible,  however 
much  the  one  may  be  superior  to  the  other.  I  think  that  any 
difficulty  in  this  respect  that  may  exist  can  be  adequately 
overcome  by  extending  the  number  of  lines,  as  has  been  done, 
by  following  always  the  same  sequence  and  by  rigidly  adhering 
o  the  rule  never  to  repeat  a  line. 

The  Subjects. — The  subjects  included  867  presumably 
normal  individuals.  These  were  in  the  main  pupils  in  the 
ordinary  grade  schools  of  about  four  or  five  different  schools 


STANDARDIZATION  OF  TESTS  381 

in  Columbus,  and  some  from  a  junior  high  school.  Most  of 
the  five-year-olds  were  kindergarten  children  and  those 
below  that  age  were  examined  in  day  nurseries  and  settlement 
houses.  About  half  of  the  adults  tested  were  university 
students.  Four  hundred  and  sixty-three  feeble-minded  in- 
dividuals were  also  tested.  The  vast  majority  of  these  were 
inmates  of  an  institution  for  the  feeble-minded,  but  there  are 
also  included  in  this  number  several  feeble-minded  children 
that  were  met  with  in  the  juvenile  court  or  in  school.  No 
systematic  attempt  was  made  to  exclude  all  cases  of  suspected 
feeble-mindedness  from  the  data  for  normal  children.  This 
would  have  involved  giving  lengthy  tests  to  some  hundreds  of 
children  in  the  public  schools.  Any  child  who  was  obviously 
feeble-minded  was  excluded  from  the  normal  group  and  if  his 
Binet  age  had  been  determined  he  was  included  among  the 
feeble-minded. 

The  tests  were  not  all  given  by  the  writer  himself,1  but  the 
technic  of  this  test  is  so  simple  that  uniformity  in  giving  it  is 
very  easily  attained.  I  do  not  think  that  any  possible  error 
from  this  source  would  materially  affect  the  results. 

The  number  of  normal  children  tested  at  each  age  is  given 
in  Table  I.  below,  and  the  feeble-minded  in  Table  IV.  The 
normal  children  are  grouped  according  to  chronological  age 
and  the  feeble-minded  according  to  Binet  age.  It  will  be 
seen  that  the  number  for  each  age  is  not  uniform,  but  a  suf- 
ficiently large  number  between  the  ages  of  five  and  sixteen  were 
obtained  for  each  age.  The  usual  difficulties  were  encountered 
in  getting  children  below  five  and  above  sixteen  years  of  age. 
The  feeble-minded  differed  chronologically  a  great  deal,  some 
of  them  were  adults  and  others  merely  children. 

Tabulation  of  the  Data. — The  actual  recording  of  the  results 
while  giving  the  tests  is  perhaps  best  done  by  making  out  some 
such  blank  as  is  shown  below,  which  is  a  copy  of  some  of  the 
actual  data. 

1  The  writer  wishes  here  to  acknowledge  the  generous  help  given  him  in  this  work 
by  Mr.  Donald  G.  Paterson,  graduate  assistant  in  the  department  of  psychology.  He 
is  also  glad  to  acknowledge  the  assistance  rendered  by  Miss  M.  Anderson  and  Miss  A. 
Beekman,  advanced  students  in  the  same  department. 


382 


RUDOLF  P1NTNER 


Name 

Age 

Grade 

A 

X 

Y 

B 

C 

D 

E 

*• 

G 

H 

I 

J 

Catherine  M.  .  . 
Paul  C  

12 

6 

55 

lA 

+ 

+ 

4- 

+ 
+ 

— 

+ 
+ 

+ 

+ 

— 

— 

+ 

— 

— 

Matilda  S  

14. 

7A 

+ 

+ 

-f 

+ 

+ 

+ 

+ 

-f 





__ 

__ 

Rosie  S  

c 

Kindg. 

W.E. 

+ 

+ 





__ 



During  the  collection  of  results  covering  in  all  about 
thirteen  hundred  cases  the  following  device  was  employed 
to  keep  an  oversight  of  the  results  as  they  came  to  hand  and 
also  to  afford  some  clue  as  to  when  sufficient  results  had  been 
collected.  As  the  results  came  in  they  were  recorded  on 
squared  paper  and  a  curve  was  slowly  built  up.  This  was  done 
for  each  separate  line  and  for  certain  groups  of  lines.  Fig.  I 
shows  the  results  for  two  lines  correct  out  of  the  BCD  lines. 

The  numbers  along  the  abscissa  represent  the  ages.  A 
mark  or  dot  above  the  line  represents  a  correct  response  and  a 
similar  mark  below  the  line  represents  a  failure.  The 
figure  shows  the  building  up  process  at  the  stage  of  completion. 
The  figures  to  the  left  of  each  column  represent  the  number 
of  cases,  the  figures  to  the  right  are  the  percentages  of  correct 
responses  for  each  age  at  different  stages  in  the  growth  of  the 
curve.  When  each  fresh  group  of  results  was  added,  the 
percentage  of  correct  responses  was  calculated  and  noted  on 
the  growing  curve.  This  device  for  recording  the  results  was 
found  to  add  a  much  greater  interest  in  the  work  than  could 
have  been  attained  by  waiting  until  all  the  data  had  been 
collected,  and  it  also  shows  the  worker  how  his  results  are 
developing.  If  the  percentages  are  calculated  every  now  and 
then,  he  can  see  whether  new  results  that  are  coming  in  are 
adding  anything  new  to  his  work  or  are  merely  confirming  the 
results  that  have  already  been  obtained.  If  the  percentage 
fluctuates  a  great  deal,  it  is  a  sign  that  more  results  are  re- 
quired; if  it  remains  more  or  less  stationary  for  some  time,  it 
may  be  assumed  that  additional  results  are  not  likely  to  affect 
the  shape  of  the  curve.  From  Fig.  I  it  will  be  seen  that  the 
percentages  for  most  ages  remained  more  or  less  constant. 
Some  slight  fluctuation  is  seen  at  age  eight,  where  the  per- 
centage drops  from  68  to  65  and  then  rises  steadily  to  74. 


STANDARDIZATION  OF  TESTS 


383 


* 

lUnminuimiiuiiimt 


e»— 
tso 


a 


IfifttimilHHHMI 
H 


HfllMlllll 


O 


J- 


Illlllll 
oo 

Him 


intuiuiiit 


| 
I 

S 


3  s 

8  ^ 

if 
-  g 
«  & 


fiiimiuunmmi 

UllinilllllllfMllllHUIMtUIHV 
<*> 

iM|lll1IH|lUllllfUIUUi(U(<lUlHI|IU 


ffllfHll 


I 


384  RUDOLF  PINTNER 

Still  more  fluctuation  is  seen  at  age  seven,  where  the  per- 
centage at  first  drops  from  62  to  58  and  then  rises  slowly  to 
69.  From  the  point  of  view  of  standarization  this  fluctuation 
of  the  percentage  becomes  important.  We  obviously  cannot 
say  that  a  test  is  a  seven-  or  eight-year-old  test,  as  the  case 
may  be,  until  we  are  certain  that  the  addition  of  subsequent 
data  is  not  likely  to  affect  our  percentages.  At  one  stage  of 
our  curve  it  might  have  seemed  that  this  particular  com- 
bination of  lines  would  have  made  a  good  eight-year-old  test, 
since  68  per  cent,  of  the  eight-year-olds  passed  it  and  only  57 
per  cent,  of  the  seven-year-olds.  As  the  other  results  were 
added,  however,  it  became  obvious  that  a  larger  and  larger 
majority  of  the  seven-year-olds  were  able  to  accomplish  it, 
practically  as  large  a  majority  as  with  the  eight-year-olds, 
and  since  this  percentage  remained  more  or  less  constant  for 
some  time,  it  may  be  safe  to  assume  that  this  group  of  lines 
(to  do  any  two  correct  out  of  the  BCD  lines)  is  a  fair  seven- 
year-old  test. 

In  a  similar  manner  curves  were  built  up  for  all  lines  of  the 
test  and  for  various  combinations  of  lines,  and  the  compara- 
tive lack  of  fluctuation  of  the  percentages  seemed  to  show  that 
additional  data  would  not  radically  alter  the  results  already 
obtained,  at  least  with  ages  five  to  sixteen  inclusive. 

Standardization. — After  the  results  had  all  been  collected 
in  this  manner,  curves  for  each  line  were  drawn  to  show  the 
percentage  of  correct  responses  for  each  age.  These  curves 
are  shown  in  Fig.  2.  The  curves  show  how  the  lines  compare 
with  each  other  in  difficulty.  There  are  four  groups  of  three 
lines  each  which  are,  as  we  mentioned  before,  about  equal  in 
difficulty.  It  will  be  seen  also  that  most  of  the  curves  are  more 
or  less  irregular  and  do  not  show  any  very  decided  increase 
from  one  age  to  the  next,  and  therefore  are  not  very  satis- 
factory from  the  point  of  view  of  standardization.  The  actual 
percentages  from  which  these  curves  have  been  drawn, 
together  with  the  total  number  of  children  tested  at  each 
age,  are  shown  in  Table  I. 


FIG.  2.     Percentage  of  Passes  at  Each  Age  for  the  Twelve  Different  Lines  of  the 


Test. 


386 


RUDOLF  PINTNER 


TABLE  I. 

NORMAL  CHILDREN.     PERCENTAGE  CORRECT  FOR  EACH  LINE  OF  THE  TEST 


Chronological 
Age 

Number 
Tested 

Lines  of  the  Test 

^ 

X 

Y 

B 

c 

D 

E 

F 

G 

H 

7 

J 

3 

II 

54 

o 

0 

9 

0 

IO 

0 

0 

0 

0 

O 

o 

4 

18 

67 

22 

II 

5 

17 

6 

O 

0 

O 

0 

O 

0 

5 

56 

80 

57 

36 

23 

50 

ii 

4 

5 

O 

0 

O 

0 

6 

59 

92 

74 

72 

44 

63 

37 

2 

H 

17 

2 

0 

2 

7 

67 

97 

90 

81 

54  66 

69 

IO 

24 

16 

O 

I 

7 

8 

70 

99 

95 

95 

66 

66 

74 

23 

21 

27 

0 

6 

9 

9 
10 

90 

88 

99 

ICO 

96 
92 

89 
90 

61 
73 

64 

68 

67 
84 

31 

34 

Ii 

32 
49 

3 
4 

6 
8 

8 
4 

ii 

77 

ICO 

95 

93 

73 

7i 

84 

47 

35 

38 

2 

ii 

18 

12 

82 

99 

89 

96 

81 

76 

9i 

56 

24 

40 

2 

15 

5 

13 

76 

100 

96 

96 

80  77 

88 

4i 

32 

51 

9 

15 

7 

14 

77 

99 

97 

97 

88 

82 

96 

58 

26 

56 

8 

26 

J7 

IS 

44 

100 

95 

95 

84  89 

89 

55 

21 

43 

7 

27 

25 

16 

30 

100 

100 

100 

90 

80 

IOO 

53 

40 

57 

10 

23 

17 

Adult  

22 

100 

98 

IOO 

9i 

77 

9i 

68 

41 

50 

9 

50 

38 

This  brings  us  to  the  question  of  standardization.  If  we 
wish  to  include  these  tests  in  any  scale  of  mental  measurement, 
it  is  necessary  to  decide  what  line  or  lines  of  the  test  we  should 
be  justified  in  demanding  that  a  child  should  pass  at  certain 
definite  years  in  his  chronological  development.  It  has  been 
arbitrarily  assumed  by  some  writers  that  a  percentage  of  75 
or  more  correct  responses  is  necessary  before  we  are  warranted 
in  placing  a  test  at  a  certain  age.  This  seems  to  be  taken  for 
granted  by  Bobertag,  Kuhlmann,  Goddard  and  others. 
Stern1  emphasises  the  75  per  cent,  standard,  without  however 
disregarding  the  amount  of  advance  at  each  age.  Rogers 
and  Mclntyre2  hold  to  the  75  per  cent,  basis.  They 
say,  "The  standard  for  a  pass  at  a  given  age  should  be  de- 
termined on  the  basis  of  actual  experience;  our  own  results 
agree  with  those  of  Bobertag  and  Goddard,  as  about  70  or 
75  percent.,"  and  further  on,  "A  test  was  considered  properly 
assigned  to  a  given  age  when  at  least  70  per  cent,  of  the  child- 
ren of  that  age  were  able  to  pass  it,"  which  shows  a  little 
weakening  from  the  rigid  75  per  cent,  standard. 

1  Stern,  'The  Psychological  Methods  of  Testing  Intelligence,'  Trans,  by  Whipple. 
Educational  Psychology  Monographs,  No.  13. 

2  Rogers  and  Mclntyre,  'The  Binet  Simon  Tests,'  The  British  Journal  of  Psy 
chology,  Vol.  VII.,  No.  3,  October,  1914. 


STANDARDIZATION  OF  TESTS  387 

Bobertag,1  discusses  the  matter  at  length  and  decides  for 
the  75  per  cent,  standard.  His  discussion  is  undoubtedly 
the  most  exhaustive  that  has  come  within  the  notice  of  the 
writer.  He  shows  the  relation  of  this  question  to  the  normal 
distribution  of  any  ability  and  makes  a  comparison  with 
pupils'  grades  as  given  by  teachers. 

On  the  other  hand  Binet  himself  nowhere  seems  to  have 
been  very  dogmatic  on  this  point.  As  far  as  one  can  discover 
he  seems  to  have  considered  a  test  standardized  if  passed  by 
from  60  to  90  per  cent,  of  the  individuals  tested.  Similarly 
Terman  and  Childs2  feel  it  impossible  to  adhere  rigidly  to  the 
75  per  cent,  standard.  They  say  that  two  thirds  ought  to 
pass  a  given  test,  but  they  lay  more  stress  upon  "a  sharp  rise 
in  ability  from  the  year  before."  It  may  be  interesting  to 
note  that  the  latter  workers  cited,  Binet  and  Terman  and 
Childs,  have  all  been  actively  engaged  in  adding  new  tests, 
whereas  the  former  are  more  especially  those  who  have  merely 
worked  with  the  tests.  It  would  seem  to  suggest  that  in 
actual  practice  there  is  some  difficulty  in  arriving  at  the  75 
per  cent,  standard. 

If  we  now  turn  to  actual  results  as  shown  in  various  stand- 
ardizations of  tests,  we  see  this  practical  difficulty.  In 
GoddardV  results  we  find  two  or  three  tests  that  have  been 
retained  in  a  given  age  where  less  than  75  per  cent,  have 
passed.  In  BobertagV  results  we  have  numerous  instances 
where  the  number  of  passes  is  not  up  to  the  75  per  cent, 
standard,  although  it  must  be  remembered  that  he  is  merely 
trying  out  the  tests  and  not  attempting  to  standardize  them. 

Bobertag,  'Ueber  Intelligenzpriifungen,'  Zeitschr.  f.  angewandie  Psychologic, 
Vol.  6,  1912,  p.  495. 

2  Terman  and  Childs,  'A  Tentative  Revision  and  Extension  of  the  Binet-Simon 
Measuring  Scale  of  Intelligence,'  Journal  of  Educational  Psychology,  Vol.  3,  Nos.  2  to  5, 
1912;  and  Terman,  'Suggestions  for  Revising,  Extending  and  Supplementing  the  Binet 
Intelligence  Tests,'  Journal  of  Psycho- A 'sthenics,  Vol.  XVIII.,  No.  I,  September,  1914, 
p.  20. 

8  Goddard,  'Two  Thousand  Children  measured  by  the  Binet  Measuring  Scale  of 
Intelligence,'  The  Pedagogical  Seminary,  Vol.  18,  June,  1911,  p.  232. 

*  Bobertag,  'Ueber  Intelligenzpriifungen,'  Zeitschr.  f.  angew.  Psychologic,  Vol.  5, 
1911,  p.  105. 


388  RUDOLF  PINTNER 

In  Winch's1  recent  re-standardization  of  the  Binet  Scale  for 
English  children  a  very  high  percentage  of  passes  is  required 
before  the  test  is  admitted  to  a  given  age.  But  the  actual 
numbers  tested  are  not  shown  clearly  and  it  is  difficult  to 
believe  that  in  so  many  cases  100  per  cent,  passed  the  tests. 
Tests  are  shifted  from  one  year  to  another  rather  too  freely 
in  the  opinion  of  the  present  writer.  If  42  per  cent,  pass  a 
given  test  at  six  years,  and  52  per  cent,  at  seven,  we  are  not 
warranted  in  assuming  that  the  test  is  an  eight-year-old  test 
without  testing  any  eight-year-old  children.  This  seems  to 
have  been  done. 

From  the  foregoing  facts  and  from  my  own  experience, 
I  am  inclined  to  believe  that  it  is  impossible  to  lay  down  a 
definite  percentage  for  the  standardization  of  a  test.  It  may 
be  that  theoretically  about  75  per  cent,  should  pass  a  given 
test,  and  probably  the  greater  number  of  children  we  test  the 
nearer  to  this  theoretical  standard  we  may  attain.  In  actual 
practice,  however,  with  large  groups  of  unselected  individuals 
this  75  per  cent,  standard  is  difficult  to  obtain,  and  for  the 
practical  placing  of  a  test  at  a  given  age  the  crucial  point 
seems  to  be  the  more  or  less  sudden  rise  in  ability  from  one 
age  to  another.  We  must  require  about  60  per  cent,  passes, 
but  beyond  that  the  best  age  for  placing  a  test  will  depend 
upon  the  shape  of  the  curve  showing  the  percentage  of  passes 
at  each  age.  It  is  significant  for  us  to  know  at  what  age  the 
ability  of  the  child  for  a  special  response  arises.  If  we  were 
to  adhere  strictly  to  the  75  per  cent,  standard,  we  might  place 
a  test  at  a  given  age  where  76  per  cent,  of  the  children  pass, 
and  where  71  per  cent,  of  the  lower  age  also  pass.  We  would 
then  be  giving  71  per  cent,  of  a  lower  age  credit  for  a  test  of 
a  higher  age.  For  example,  on  curve  C  Fig.  2,  we  have  76 
per  cent,  of  the  twelve-year-olds  passing  the  C  line,  and  71 
per  cent,  of  the  eleven-year-olds.  It  would  seem  to  me  to  be 
obviously  wrong  to  give  the  71  per  cent,  eleven-year-olds 
credit  for  a  twelve-year-old  test  standardized  by  this  75  per 
cent,  procedure. 

1  Winch,  'Binet's  Mental  Tests;  What  They  Are  and  What  We  Can  Do  with 
Them,'  Child  Study,  Vol.  VII.,  Nos.  i  to  8,  1914. 


STANDARDIZATION  OF  TESTS  389 

It  will  now  be  clear  what  I  meant  by  saying  above  that 
the  curves  in  Fig.  2  are  not  satisfactory  from  the  point  of  view 
of  standardization.  The  curves  rise  gradually  and  many  of 
them  do  not  show  any  sudden  rise  that  might  warrant  us  in 
placing  the  test  at  any  special  age.  .From  my  point  of  view 
we  must  look  for  some  other  way  to  make  our  results  useful 
as  actual  tests.  If  we  group  our  lines  and  mass  the  results 
for  various  combinations  of  lines,  we  get  the  curves  shown  in 
Figs.  3  and  4. 

Curve  i  XY  shows  the  percentage  of  those  who  passed 
one  correct  of  the  X  or  Y  lines;  curve  I  BCD  shows  those  who 
accomplished  one  line  correctly  out  of  the  B,  C  or  D  lines; 
curve  2  BCD  those  who  did  two  of  the  B,  C  or  D  lines;  curve 
I  EFG  those  who  did  one  of  the  E,  F  or  G  lines;  curve  3  BCD 
those  who  did  three  of  the  B,  C  and  D  lines,  i.  e.,  all  three 
lines  correctly;  curve  2  EFG  those  who  did  two  of  the  E,  F  or 
G  lines;  and  curve  2  EFGHIJ  those  who  did  two  out  of  the 
six  lines  from  E  to  /.  All  these  curves  are  much  more  satis- 
factory from  the  point  of  view  of  standardization  with  the 
exception  of  the  curve  2  EFG.  From  this  group  of  lines 
(2  EFG)  it  is  impossible  to  get  a  test,  at  least  under  the  age 
of  sixteen,  because  the  percentage  nowhere  rises  above  50, 
and  this  is  too  low  for  the  standardization  of  a  test.  Other 
combinations  of  the  E,  F  and  G  lines  were  not  drawn,  since  it 
is  obvious  that  three  correct  out  of  the  EFG  lines  would  show 
still  smaller  percentages  at  all  ages.  Similarly  the  H,  I  and/ 
lines  proved  themselves  too  difficult.  The  highest  percentage 
of  passes  for  the  H  line  is  10  per  cent,  at  sixteen;  for  the  /  line 
27  per  cent,  at  fifteen;  and  for  the  /  line  25  per  cent,  at  fifteen. 
Combinations  of  these  lines  would  obviously  not  rise  above 
50  per  cent,  and  so  they  must  be  discarded  at  least  as  tests 
suitable  for  ages  below  sixteen. 

Discarding  the  2  EFG  lines,  we  have  six  curves  that  seem 
to  show  all  the  characteristics  essential  for  the  standardi- 
zation of  a  test.  Curve  i  XY  shows  a  marked  rise  between 
ages  four  and  five,  from  22  per  cent,  to  66  per  cent,  and  from 
that  place  onwards  to  84  per  cent.,  95  per  cent,  and  then  re- 


f       S       <f      10      II      12.      IS 


<fy.3lf-St>}8y/OU 

FIG.  3.    Percentage  of  Passes  for  Different  Combinations4 of  the  Lines. 


STANDARDIZATION  OF  TESTS 


39' 


mains  in  the  nineties  until  100  per  cent,  is  reached  at  age 
fourteen.  This  means  that  the  vast  majority  of  children  of 
five  years  and  over  are  able  to  do  correctly  any  one  line  of  the 


t* 

€0 

7° 


30 
20 

to 


2EF6H1J. 


Op.  6       /       8       f       /O      II      IZ      /3      tif-     IS      « 

FIG.  4.     Percentage  of  Passes  for  Different  Combinations  of  the  Lines. 

X  and  Y  lines,  whereas  very  few  of  those  below  five  years  can 
do  this.  Curve  I  BCD  shows  a  marked  rise  between  five 
and  six  years,  from  56  to  83  per  cent.  Only  about  half  of  the 


392  RUDOLF  PINTNER 

five-year-olds  can  do  one  line  of  the  BCD  lines  correctly  and 
so  it  is  obviously  not  a  five-year-old  test,  whereas  it  is  well 
within  the  ability  of  the  six-year-olds.  Curve  2  BCD  shows 
a  sudden  rise  between  six  and  seven,  from  39  to  69  per  cent. 
This  is  obviously  a  seven-year-old  test.  Curve  I  EFG  shows 
its  most  significant  rise  between  nine  and  ten,  from  58  to  69 
per  cent.  This  is  not  such  a  marked  rise  as  in  the  other  cases, 
but  is  probably  sufficient  to  warrant  a  placing  of  the  test  at 
ten  years.  It  would  seem  in  general  that  the  higher  the  ages 
the  less  marked  are  the  rises  in  the  curves,  owing  to  the  well- 
known  fact  that  one  year  in  the  lower  ages  means  a  greater 
advance  in  the  development  of  intelligence  than  in  the  higher 
ages.  It  would  seem  to  me  that  this  test  is  correctly  placed 
at  ten  years,  since  the  difference  between  the  percentages  at 
nine  and  ten,  58  and  69  per  cent.,  is  greater  than  the  differ- 
ences between  the  percentages  at  ten  and  eleven,  69  and  73 
per  cent.,  or  between  those  at  eleven  and  twelve,  73  and  77 
per  cent.  This  curve  would  also  illustrate  well  the  fallacy  of 
adhering  rigidly  to  the  75  per  cent,  standard.  If  we  were  to 
do  this  we  would  have  to  consider  it  a  twelve-year-old  test 
and  give  such  credit  to  73  per  cent,  of  the  eleven-year-olds 
and  to  69  per  cent,  of  the  ten-year-olds.  Curve  3  BCD  shows 
a  marked  rise  between  thirteen  and  fourteen  years,  from  52  to 
71  per  cent.  It  is  to  be  noted,  however,  that  the  twelve- 
year-olds  with  59  per  cent,  passes  do  better  than  the  thirteen- 
year-olds  with  only  52  per  cent,  passes.  But  the  difference 
between  59  and  71  per  cent,  seems  sufficient  to  place  the  test 
at  age  fourteen.  Again  fifteen-year-old  children  do  more 
poorly  on  this  combination  than  do  the  fourteen-year-olds, 
only  65  per  cent,  passing.  This  may  be  explained,  perhaps, 
by  the  fact  that  the  majority  of  these  were  pupils  in  the  grades 
and  very  probably  slightly  below  normal.  The  sixteen-year- 
olds  do  well.  A  good  many  of  them  were  high  school  pupils. 
It  was  surprising  to  me  to  find  that  a  correct  passing  of  all 
the  three  lines,  BCD,  is  delayed  until  about  the  fourteenth 
year.  Six-year-olds  can  accomplish  one  and  the  one  passed 
by  most  of  them  is  the  C  line.  With  children  between  the 
ages  of  six  to  thirteen  we  find  a  large  number  of  them  passing 


STANDARDIZATION  OF  TESTS 


393 


each  line  regarded  singly,  (see  curves  B,  C  and  D,  Fig.  2), 
but  it  seems  extremely  difficult  for  the  same  child  to  pass 
all  three  without  a  mistake.  Perhaps  the  close  attention 
demanded  is  beyond  the  powers  of  the  younger  child.  Or 
again  the  similarity  of  the  moves  may  be  confusing  to  the 
child,  when  line  follows  line  with  only  a  slight  difference 
between  them. 

Curve  2  EFGHIJ  shows  a  marked  rise  between  fifteen 
and  sixteen  years,  from  55  to  75  per  cent.,  although  we  have 
59  per  cent,  of  the  fourteen-year-olds  passing  this  combina- 
tion. The  rise  from  59  to  75  per  cent,  is  no  doubt  sufficient 
to  standardize  this  test  and  yet  I  feel  some  doubt  in  regard 
to  the  results  in  this  case.  The  fifteen-year-old  children 
were  not  on  the  whole  as  typical  of  their  age  as  the  children 
of  the  other  ages.  They  were  mainly  children  from  the  grades 
with  a  sprinkling  of  high  school  students.  Almost  every  curve 
shows  their  deficiency  as  contrasted  with  the  fourteen-year- 
olds.  It  may  be  therefore  that  two  out  of  the  E  to  /  lines  is  a 
fifteen-year-old  test.  This  is  possible,  although  in  view  of 
the  results  obtained  not  very  probable. 

TABLE  II 

NORMAL  CHILDREN.    PERCENTAGE  CORRECT  FOR  VARIOUS  COMBINATIONS 
OF  THE  I.INES  OF  THE  TEST 


Chrono- 
logical 
Age 

Number 
Tested 

Combinations  of  Lines 

iXY 

T.BCD 

2BCD 

T.EFG 

$BCD 

*EFGHIJ 

3 

II 

0 

10 

9 

0 

0 

0 

4 

18 

22 

22 

6 

0 

0 

0 

56 

66 

56 

21 

II 

7 

0 

6 

59 

•84' 

83 

39 

20 

22 

8 

7 

6? 

95 

87 

69 

39 

36 

16 

8 

70 

98 

89 

74 

53 

45 

18 

9 

90 

99 

91 

72 

58 

30 

28 

10 

88 

96 

97 

86 

69 

44 

38 

ii 

77 

97 

97 

83 

73 

50 

38 

12 

82 

97 

k       96 

93 

77 

59 

4i 

13 

76 

99 

99 

89 

76 

52 

43 

14 

77 

100 

99 

97 

78 

7i 

59 

15 

44 

100 

IOO 

93 

77 

65 

55 

16 

30 

IOO 

IOO 

93 

84 

80 

75 

Adult.... 

22 

100 

IOO 

9i 

86 

77 

Table  II.  shows  the  results  for  the  six  combinations,  which 
we  believe  can  be  satisfactorily  used  as  tests.     In  each  case 


394  RUDOLF  PINTNER 

the  number  tested  at  each  age  and  the  percentage  of  correct 
responses  is  given.  It  will  be  seen  that  an  attempt  was  made 
to  test  large  numbers  of  children  at  each  age.  Even  although 
the  experimenter  often  felt  that  a  given  line  was  far  too 
difficult  for  a  child,  yet  it  was  given  in  order  to  get  the  negative 
results,  without  which  no  real  standardization  of  a  test  is 
possible.  It  is  just  as  important  to  know  that  the  children 
below  a  given  age  cannot  pass  the  test  as  to  know  that  those 
'of  a  given  age  can  pass  it,  and  the  comparison  between  the 
two  ages  is  not  a  just  one  unless  equal  numbers  of  both  ages 
in  question  have  been  tested.  Much  of  the  work  in  standard- 
ization done  up  to  the  present  time  is  open  to  just  this 
criticism.  In  Goddard's  figures  for  the  revision  of  the  Binet 
Scale  we  find  tests  placed  at  a  given  year  because  of  a  high 
percentage  of  passes  obtained  from  about  100  children, 
whereas  only  between  thirty  to  forty  children  and  sometimes 
even  fewer  of  the  next  lower  age  had  been  tested.  From  my 
experience  with  the  results  from  this  test  and  with  others 
upon  which  work  is  now  being  done,  it  seems  to  me  to  be 
dangerous  to  take  for  granted  that  a  few  results  in  the  age 
below  the  test  age  are  sufficient  negative  evidence  to  exclude 
the  possibility  of  the  test  falling  at  that  age.  It  is  generally 
conceded  that  the  tests  at  the  lower  end  of  the  Binet  Scale 
are  too  easy  and  an  inspection  of  Goddard's  figures  will  show 
that  in  the  six-year-old  tests,  for  example,  only  about  half 
and  in  some  cases  less  than  half  of  the  children  at  the  test 
age  were  tested  in  the  age  below  the  test  age.  In  Table  II. 
it  will  be  seen  that  the  first  test  of  the  Knox  Cubes — I  .XT- 
is  open  to  just  the  criticism  that  I  have  been  urging.  There 
are  56  five-year-olds  and  only  18  four-year-olds.  This  is 
owing  to  the  fact  that  I  experienced  great  difficulty  in  getting 
four-year-olds.  It  may  be  that  if  fifty  four-year-olds  were 
tested,  this  combination  of  lines  might  prove  a  four-year-old 
test,  and  yet  I  do  not  believe  this  would  be  the  case  and  so  I 
have  considered  it  a  five-year-old  test.  To  none  of  the  other 
tests  can  this  criticism  apply.  Large  numbers  above  and 
below  the  test  age  have  been  tested  and  there  are  sufficient 
negative  results  below  the  test  age  in  each  case. 


STANDARDIZATION  OF  TESTS 


395 


Total  Number  of  All  Lines  Passed. — The  results  of  the 
test  were  also  tabulated  in  another  manner  to  show  the  number 
of  lines  passed  correctly  at  each  age.  The  total  number  of 
lines  passed  correctly  by  each  child  was  added  together  and 
the  average  and  average  deviation  for  each  age  found.  These 
figures  are  shown  in  Table  III. 

TABLE  III 

AVERAGE  NUMBER  OF  LINES  PASSED  AT  EACH  AGE 


Chronological 
Age 

Av.  Number  of 
Lines  Passed 

A.  D. 

3 

0-57 

0.49 

4 

.1-43 

0.76 

5 

,2.41 

•17 

77  %  Pass  2  °r  more  lines. 

6 

4.22 

.25 

71%  pass  4  or  more  lines. 

7 

5-12 

.28 

70%  pass  5  or  more  lines. 

8 

5.60 

.18 

9 

5-59 

•34 

10 

6.29 

•32 

72%  pass  6  or  more  lines. 

ii 

6.68 

.76 

12 

6.66 

.10 

*3 

6.66 

.41 

14 

15 

7-SS 
7-45 

2 

75%  Pass  7  °r  more  lines. 

16 

8.05 

.11 

62%  pass  8  or  more  lines. 

It  will  be  seen  that  there  is  an  almost  steady  increase  in 
the  number  of  lines  accomplished  from  age  four  up  to  age 
eleven,  where  it  becomes  almost  stationary  at  6.6,  to  rise 
again  at  age  14  up  to  age  16.  In  no  case  is  the  average 
deviation  larger  than  1.7. 

The  results  in  this  form  may  not  be  so  suitable  for  the 
placing  of  a  test  at  a  definite  age,  but  they  could  of  course  be 
incorporated  in  a  scale.  They  show  a  very  close  correlation 
with  the  lines  which  I  have  considered  standardized.  Age 
four  can  do  one  line,  that  is  the  A  line,  and  they  are  not  able 
to  do  one  out  of  XY.  Age  five  can  do  two  lines,  that  is  the 
A  line  and  either  X  or  Y.  Age  six  can  do  four  lines,  that  is 
the  AXY  lines  and  one  out  of  BCD.  Age  seven  can  do  five 
lines,  that  in  AXY  and  two  out  of  BCD.  Ages  eight  and 
nine  cannot  do  more  than  five  lines,  that  is  AXY  and  two 
out  of  BCD  and  not  one  out  of  EFG.  Age  ten  can  do  six 
lines,  that  is  AXY  and  two  out  of  BCD  and  one  out  of  EFG. 


396  RUDOLF  PINTNER 

Ages  eleven,  twelve  and  thirteen  all  show  an  accomplishment 
of  a  little  more  than  six  but  not  seven  lines,  that  is  they  can 
do  AXY,  two  out  of  BCD  and  one  out  of  EFG,  but  they  cannot 
do  all  BCD  nor  two  out  of  EFG,  as  our  curves  have  already 
shown  us.  Age  fourteen  and  above  can  do  seven  lines,  that  is 
AXYBCD  and  one  out  of  EFG.  Age  sixteen  can  do  eight 
lines,  that  is  AXYBCD  and  two  out  of  the  remainder.  All 
this  serves  to  corroborate  our  placing  of  the  lines  at  partic- 
ular ages.  There  is  of  course  no  reason  why  this  method 
should  not  be  used  in  crediting  for  different  ages.  In  that 
case  we  should  expect  at  five  years  two  lines  to  be  passed  cor- 
rectly; at  six  years  four  lines;  at  seven  years  five  lines;  at  ten 
years  six  lines;  at  fourteen  years  seven  lines  and  at  sixteen 
years  eight  lines. 

There  does  not  seem  to  be  very  much  difference  in  marking 
between  the  two  methods.  In  33  cases  examined  nineteen 
gave  the  same  results  for  both  methods;  the  other  cases  showed 
a  slightly  lower  age  estimate  when  the  system  of  marking  by 
total  number  accomplished  correctly  was  used. 

In  twenty  cases  where  the  Binet  ages  were  available  for 
comparison  the  estimate  of  age  from  performance  on  the  Knox 
Cubes  agreed  with  the  Binet  age  in  seven  cases  by  the  group 
method  and  in  eight  cases  by  the  total  number  method. 
The  average  amount  of  difference  between  the  Binet  age  and 
the  age  as  estimated  by  the  Knox  Cubes  was  2.17  years  for 
the  group  method  and  2.36  for  the  total  number  method  of 
using  the  cubes.  Apart  from  the  slight  differences  in  results 
obtained  by  these  two  methods  of  marking  for  the  test,  it  is 
also  interesting  to  note  how  well  on  the  whole  the  estimate  of 
mental  age  agrees  with  that  arrived  at  by  the  Binet  Scale. 
It  is  surprising  that  any  one  test  should  come  so  near  the 
result  arrived  at  by  a  whole  series  of  tests.  I  do  not  mean  by 
this  to  suggest  that  the  Knox  Cube  Test  alone  should  ever 
be  used  to  compute  mental  age.  It  must,  of  course,  take  its 
place  in  a  series  of  mental  tests. 

Perseveration  and  Reverse  Order. — Two  definite  types  of 
errors  occur  in  this  test  to  warrant  a  few  words.  The  first  I 
have  called  perseveration.  It  consists  in  repeating  the  A  line 


STANDARDIZATION  OF  TESTS  397 

after  the  examiner  has  continued  with  other  lines  of  the  test. 
The  child  does  not  seem  to  notice  that  the  X  or  B  or  C  line, 
as  the  case  may  be,  is  different  from  the  A  line  with  which  he 
started.  There  is  a  perseveration  of  the  tendency  to  tap  the 
blocks  in  the  order  given  first,  which  also  happens  to  be  a  very 
easy,  natural  order.  The  child  taps  one,  two,  three,  four, 
again  and  again,  sometimes  adding  some  other  moves  to  these 
first  four.  This  error  of  perseveration  is  not  common  among 
the  older  children.  Only  one  of  our  fourteen-year-olds  did 
this,  and  from  his  performance  in  other  tests  it  is  very  probable 
that  this  child  is  defective.  Of  the  other  children  we  found 
one  case  at  12  years,  one  at  9,  one  at  8,  five  at  7,  three  at  6, 
six  at  5,  one  at  4,  and  two  at  3,  and  it  is  to  be  remembered 
that  relatively  few  three-  and  four-year-olds  were  tested.  It 
would  seem  then  that  this  error  is  due  to  the  lower  stage  of 
intelligence  of  the  child,  and  perhaps  one  that  may  be  a 
clue  to  possible  feeble-mindedness.  This  idea  is  strengthened 
by  the  frequency  of  this  error  among  our  feeble-minded  cases. 
This  occurred  as  follows: 

At  mental  age  2 3  times 

3 *    " 

4 10    " 

5 16    " 

6 22      " 

7 10    " 

8 3    " 

10 2      " 

II I  " 

This  makes  a  total  of  72  cases  among  the  feeble-minded  as 
contrasted  with  21  among  the  normal  children.  With  the 
feebleminded  as  with  the  normal,  we  notice  a  larger  percentage 
of  cases  among  the  children  of  lower  mental  age. 

The  second  error  is  that  of  reverse  order,  i.  e.,  beginning 
with  the  block  at  the  child's  right  instead  of  with  the  block 
at  his  left,  which  is  the  one  touched  first  by  the  examiner. 
This  was  noted  as  "wrong  end."  It  occurs  most  frequently 
with  the  A  line  and  rarely  is  peristed  in  for  more  than  three  or 
four  lines.  It  is  again  an  error  found  more  often  among  the 
younger  children,  but  it  cannot  be  said  to  be  particularly 


RUDOLF  PINTNER 


characteristic  of  the  feebleminded, 
cases  were  noted: 

NORMAL 
Chronological  Age 

Age  3 i  time. 

4 4  times 

5 7     " 

6..  ..4     " 


8. 


The  following  number  of 

FEEBLE-MINDED 
Mental  Age 

Age  2 2  times. 

4 2    " 

5 i     " 

6 2    " 

7 i     " 

8 i     " 

No  credit  was  allowed  for  this  error.  It  was  treated  always 
as  a  mistake,  even  although  the  line,  whether  the  A  line  or  a 
more  complicated  line,  was  in  other  respects  correctly  per- 
formed. In  a  system  of  mental  classification  giving  a  number 
of  points  for  each  test  or  computing  by  whole  or  half  credits, 
it  might  be  justifiable  to  given  this  error  a  half  credit  or  a  fewer 
number  of  points. 

The  Feeble-minded. — Four  hundred  and  sixty-three  feeble- 
minded individuals  were  given  the  same  test.  These  were 
inmates  of  an  institution1  and  all  of  them  had  been  graded  by 
the  Binet  Scale.  They  have  been  classified  according  to 
mental  age  and  the  percentage  correct  for  the  different  lines 
is  shown  in  Table  IV.  and  for  the  various  combinations  of 
lines  in  Table  V.  Their  performance  in  some  of  the  com- 
binations of  lines  is  shown  by  curves  on  Fig.  3.  On  the  whole 

TABLE  IV 

FEEBLE-MINDED.    PERCENTAGE  CORRECT  FOR  EACH  LINE  OF  THE  TEST 


Mental  Age 

Number 
Tested 

Lines  of  the  Test 

A 

X 

K 

B 

C 

D 

E 

F 

G 

H 

/ 

J 

2 

6 

50 

o 

0 

0 

o 

O 

O 

O 

o 

0 

0 

0 

3 

7 

17 

14 

0 

0 

0 

14 

0 

O 

o 

O 

o 

o 

4 

17 

76 

17 

8 

6 

12 

12 

0 

o 

o 

O 

o 

o 

1 

£ 

92 
97 

l\ 

21 

19 
19 

27 
40 

8 

5 
7 

8 
6 

13 

O 
0 

o 

0 

o 

0 

7 

85 

99 

87 

14 

41 

36 

4 

2 

8 

0 

0 

2.5 

8 

73 

99 

98 

82 

55 

62 

71 

20 

26 

19 

1.5 

1.5 

4 

9 

75 

IOO 

97 

79 

71 

67 

21 

24 

20 

2.1 

1 

7 

10 

69 

IOO 

89 

92 

69 

67 

87 

35 

33 

30 

0 

IO 

9 

ii 

27 

IOO 

IOO 

IOO 

66 

70 

89 

29 

29 

7 

15 

ii 

1  The  writer  wishes  here  to  acknowledge  the  kindness  and  courtesy  of  Dr.  Emerick, 
superintendent  of  the  Ohio  Institute  for  the  Feeble-minded. 


STANDARDIZATION  OF  TESTS 
TABLE  V 


399 


FEEBLE-MINDED.    PERCENTAGE   CORRECT  FOR  VARIOUS   COMBINATIONS  OF 
THE  LlNES  OF  THE  TEST 


Mental  Age. 

Number  Tested 

Combinations  of  Lines 

i  XY 

x  B  CD 

aB  CD 

rEFG 

*EFG 

2 

6 

O 

0 

0 

0 

0 

3 

7 

14 

14 

0 

0 

0 

4 

17 

17 

12 

12 

0 

0 

1 

67 

39 

65 

32 

49 

H 
17 

14 
14 

9 

3 

7 

85 

92 

59 

38 

II 

3-5 

8 

73 

97 

82 

66 

42 

22 

9 

75 

100 

80 

68 

49 

16 

10 

69 

100 

93 

78 

30 

ii 

27 

100 

93 

78 

63 

22 

the  curves  follow  those  of  the  normal  children  pretty  closely, 
generally  remaining  a  little  below.  This  means  that  the 
normal  children  as  a  whole  do  slightly  better  on  this  test  than 
the  feeble-minded  of  corresponding  mental  age.  In  the  lower 
ages — three  and  four — the  curve  for  the  feeble-minded  is  very 
close  to  and  sometimes  even  rises  above  the  curve  for  the 
normals.  This  corresponds  to  the  well-known  fact  that  the 
Binet  Scale  is  too  easy  at  the  lower  end.  Only  in  one  curve, 
I  XY,  do  we  see  the  feeble-minded  curve  rising  above  the 
normal  curve.  In  all  the  other  curves  it  remains  below  the 
normal,  although  sometimes  it  is  very  near  the  normal.  The 
feeble-minded  individuals  of  the  higher  mental  ages,  ten  to 
eleven,  do  not  surpass  normal  children  of  corresponding  chro- 
nological age,  so  that  in  this  test  we  find  no  corroboration  of 
the  fact  that  the  Binet  Scale  is  too  difficult  at  the  upper  end. 
This  is,  of  course,  not  to  be  taken  as  a  denial  of  the  difficulty 
of  the  higher  tests  of  the  Binet  Scale,  although  none  of  the 
tests  have  been  subjected  to  the  rigid  standardization  as  has 
been  undertaken  for  this  test.  It  may  be  that  this  cube  test 
is  testing  something  that  is  not  tested  by  the  tests  at  the 
upper  end  of  the  Binet  Scale.  It  demands  concentration  of 
attention  to  a  continuously  varying  task  and  it  requires  the 
subject  to  work  at  a  pace  that  is  set  for  him.  The  feeble- 
minded are  not  by  any  means  lacking  in  attention  and  per- 
severance. Many  will  work  for  long  stretches  of  time  at  a 


400  RUDOLF  PINTNER 

task  with  the  greatest  concentration  of  attention,  but  if  their 
attention  is  required  for  a  certain  definite  period  to  a  changing 
stimulus,  it  seems  difficult  for  them  to  adjust  their  attention 
to  the  continuously  varying  aspects  of  the  problem.  It  is 
probable  that  many  of  the  feeble-minded  would  do  much 
better  if  the  blocks  were  tapped  not  at  a  given  constant  rate, 
but  at  a  rate  varying  with  their  ability  to  shift  their  attention 
from  the  one  block  to  the  other.  In  terms  of  rhythm,  we 
might  say  that  the  feeble-minded  individual  is  too  dependent 
upon  his  own  individual  rhythm,  and  that  he  lacks  the 
capacity  of  adjusting  himself  readily  to  external  rhythms. 

Summary. — The  Knox  Cube  Test  given  to  normal  children 
and  standardized  for  the  different  ages  gives  the  following 
tests : 

i  out  of  XY  lines 5  year  test. 

1  out  of  BCD  lines 6     "      " 

2  out  of  BCD  lines 7     "       " 

1  out  of  EFG  lines 10     "      " 

3  out  of  BCD  lines 14     "       "     (probably). 

2  out  of  EFGHIJ  lines 16     "      "     (probably). 

In  actually  using  this  method  it  would  seem  well  to  credit  the 
child  with  the  age  at  which  the  most  difficult  combination  is 
passed.  The  child  who  passes  2  BCD  is  credited  with  a  five-, 
six-  and  seven-year-old  test,  even  although  he  may  have 
failed  in  one  of  the  easier  combinations,  the  presumption 
being  that  the  failure  was  not  due  to  an  inability  to  pass 
these  easier  lines,  but  to  some  disturbing  factor  foreign  to  the 
test. 

The  actual  number  of  lines  passed  may  also  be  used  as  an 
index  to  mental  age,  and  if  this  method  is  followed  we  must 
give  credit  in  this  manner: 

For  2  or  3  lines 5-year  credit. 

"    4  lines 6     " 

"    5    "    7    " 

"    6    "    10    " 

"    7    "    14    " 

"    8    " 16    " 

In  using  this  test  it  would  be  well  to  follow  strictly  the 
directions  given  at  the  beginning  of  this  article,  since  any 


STANDARDIZATION  OF  TESTS 


401 


deviation  from  this  method  is  likely  to  give  different  results. 
Touch  the  blocks  at  a  uniform  rate,  beginning  with  the  cube 
at  the  child's  left,  never  repeat  a  line  and  do  not  give  the 
child  any  suggestion  of  counting. 

In  conclusion,  the  justification  for  a  long  article  such  as 
this  one  that  deals  solely  with  a  single  test  may  be  found  in 
the  fact  that  up  to  now  we  have  been  more  or  less  satisfied 
with  a  very  indifferent  standardization  of  the  mental  tests 
that  are  being  widely  used  in  computing  mental  age.  We 
have,  in  fact,  been  avoiding  the  hard  work  and  an  inadequate 
solution  of  the  problem  of  standardization.  Only  by  a  thor- 
oughgoing treatment  of  each  and  every  test,  such  as  has  been 
attempted  here,  will  we  ever  arrive  at  tests  that  will  give  us 
something  more  than  a  mere  approximation  to  a  child's 
mental  age.  A  scale  made  up  of  different  tests  standardized 
in  this  fashion  might  lay  claim  to  some  exactitude.  I  think 
emphasis  must  be  laid  on  the  number  tested  before  we  can 
rest  satisfied  with  the  standardization  of  any  test,  and  in  this 
connection  it  seems  most  important  to  me  to  have  practically 
the  same  number  of  cases  in  the  ages  immediately  above  and 
below  the  test  age,  as  we  have  in  the  test  age  itself.  We  dare 
not  assume  that  the  age  below  the  test  age  cannot  accomplish 
a  given  test  unless  we  have  sufficient  negative  results  in  that 
age.  Our  knowledge  of  general  intelligence  and  the  develop- 
ment of  intelligence  is  so  limited  that  it  is  very  dangerous  to 
take  anything  for  granted  on  an  a  priori  basis. 


THE  ADEQUACY  OF  THE  LABORATORY  TEST  IN 

ADVERTISING 

BY  H.  F.  ADAMS 

University  of  Michigan 

That  it  is  possible,  by  means  of  a  simple  experiment,  to 
tell  even  roughly  the  relative  amount  of  business  which 
each  of  a  series  of  advertisements  will  bring  in,  is  a  revolu- 
tionary idea.  The  feasibility  of  such  a  prediction,  however, 
has  been  indicated  by  the  writings  of  Strong  and  Holling- 
worth.  Granting  this  assumption  to  be  true,  it  opens  up  an 
entirely  new  field  of  experimentation  for  the  practical  psy- 
chologist. Not  only  that,  but  it  should  result  in  the  develop- 
ment of  a  series  of  principles  which  would  be  of  the  greatest 
benefit  to  the  advertising  man.  The  historical  summary  will 
show  the  evidence  upon  which  the  assumption  is  based. 

HISTORICAL  SUMMARY 

Chronologically,  the  first  experiment  which  I  have  found 
comparing  the  results  obtained  by  laboratory  and  business 
methods  was  performed  with  a  set  of  five  Bullard  Lathe 
Advertisements.1  Ten  subjects,  mechanics  and  engineering 
students,  were  used.  They  were  told  to  arrange  the  adver- 
tisements 'in  the  order  in  which  you  would  buy  the  machine.' 
From  the  results,  the  relative  position  of  each  advertisement 
in  the  series  was  obtained.  The  order  as  determined  in  this 
way  was  then  compared  Svith  the  actual  number  of  replies 
for  catalogues  received  by  the  Bullard  Co.  from  each  adver- 
tisement.' It  was  found  that  the  two  orders  agreed  perfectly. 

Another  similar  experiment  was  performed  with  a  set  of 
Packer's  Tar  Soap  advertisements.2  Fifty  advertisements 

1  Strong,  'The  Relative  Merit  of  Advertisements/  IO-H.  Hollingworth,  'Ad- 
vertising and  Selling,'  8-10. 

•Strong,  'The  Relative  Merit  of  Advertisements,'  11-15:  63-81;  Jour,  of  Phil., 
Psy.t  etc.,  VIII.,  600-606.    Hollingworth,  'Advertising  and  Selling,'  11-14. 
402 


TESTS  IN  ADVERTISING  403 

were  arranged  by  twenty-five  subjects  'in  the  order  in  which 
you  would  buy  the  soap.' 

"When  the  order  was  compared  with  the  order  submitted 
by  Mr.  Edward  A.  Olds,  Jr.,  of  the  Packer  Manufacturing 
Company,  and  with  the  one  from  the  Blackman-Ross  Adver- 
tising Agency,  we  found  a  high  degree  of  similarity  between 
the  three  orders.  The  resemblance  between  the  experimental 
order  and  either  of  the  other  two  is  equal  to  a  coefficient  of 
correlation  of  plus  .52.  The  resemblance  between  the  order 
of  the  Packer  Manufacturing  Co.  and  the  Blackman-Ross 
Agency  is  equal  to  plus  .64.  There  is  then  nearly  as  great 
agreement  between  the  experimental  order  and  that  of  the 
Packer  Manufacturing  Co.  as  between  the  latter  and  the 
agency,  which  is  now  handling  their  advertising  business." 

Eight  advertisements  out  of  the  50  were  then  selected  for  a 
more  detailed  study.  These  advertisements  were  arranged 
by  100  subjects,  60  men  and  40  women.  The  following  co- 
efficients of  correlation  were  found  to  exist: 

Between  100  subjects  and  25  subjects 947 

100  subjects  and  Packer  Co 893 

100  subjects  and  B.-R.  Agency 866 

25  subjects  and  Packer  Co 840 

25  subjects  and  B.-R.  Agency 920 

Packer  Co.  and  B.-R.  Agency 866 

A  third  set  of  experiments  was  performed  with  Electric 
Light  Advertisements.1  There  were  originally  in  the  set 
five  advertisements,  but  only  three  were  used.  For  in  two 
of  them  there  was  a  difference  in  one  respect  which  affected 
the  company's  data  so  much  as  to  render  them  unsuitable 
for  the  experiment.  Thirty-six  subjects  were  used.  Working 
the  results  of  the  three  advertisements  out  by  the  order  of 
merit  method,  Strong  found  a  coefficient  of  correlation  of 
plus  i.oo  between  the  order  as  determined  by  the  laboratory 
test  and  by  the  business  returns. 

Hollingworth,2  who  gives  what  are  apparently  the  returns 
from  all  five  advertisements  in  the  set,  finds  a  coefficient  of 

1  Strong,  Jour,  of  Ed.  Psy.,  IV.,  393-404. 

8  Hollingworth,  'Advertising  and  Selling,'  14-15. 


404  H.  F.  ADAMS 

correlation  of  plus  .60  between  the  laboratory  returns  and  the 
business  returns  as  measured  by  the  cost  per  inquiry. 

There  have  been  made,  then,  three  tests,  the  reports  of 
which  are  accessible  in  the  psychological  literature,  deter- 
mining the  correlation  between  the  laboratory  test  and  the 
business  test.  The  lowest  coefficient  is  plus  .52;  the  highest 
is  plus  i.oo.  The  average  is  in  the  neighborhood  of  plus  .82. 
The  general  conclusion  drawn  is  that  the  laboratory  test  is  a 
satisfactory  preliminary  for  any  set  of  advertisements  which 
is  to  be  used  in  business.  For  by  it  the  poorer  advertise- 
ments can  be  eliminated  and  only  the  best  kept.  The 
business  returns  and  the  laboratory  returns  agree  so  closely 
that  each  can,  in  general,  be  used  as  a  measure  of  the  other. 

Strong2  also  worked  out  the  coefficient  of  correlation 
between  the  results  of  groups  of  persons  coming  from  different 
walks  of  life.  His  general  conclusion  is:  "A  group  of  50 
college  students  will  represent  very  closely  the  judgment  of 
groups  of  educated  business  men  and  women,  of  young 
business  men,  such  as  attend  evening  schools,  etc.,  and  of 
women  of  the  middle  class  regardless  of  age.  They  will  not 
represent  at  all  the  judgment  of  groups  from  small  towns  and 
farming  sections  such  as  the  regions  around  Garrison,  N.  Y., 
from  which  the  data  were  obtained. 

"It  is  fair  to  extend  the  results  as  set  forth  in  previous 
chapters  regarding  the  judgment  of  college  students  to  groups 
of  educated  men  and  women  in  general.  But  as  the  data  of 
this  report  are  mainly  concerned  with  cheap  articles  in 
common  use,  very  little  can  be  postulated  concerning  the 
relation  of  various  groups  of  individuals  with  regard  to  more 
expensive  commodities." 

EXPERIMENTAL  RESULTS 

In  view  of  the  last  sentence  of  the  quotation  given  above, 
it  was  thought  that  some  profitable  data  might  be  disclosed 
by  the  study  of  an  entirely  different  kind  of  advertising  ma- 
terial, such  as  that  of  a  mail  order  business. 

The  experimental  work  was  done  by  John  S.  Deuble,  in  the 

2  Strong,  'The  Relative  Merit  of  Advertisements,'  62. 


TESTS  IN  ADVERTISING  405 

psychological  laboratory  at  the  University  of  Michigan.  The 
results  were  put  in  their  final  form  by  the  writer. 

Three  sets  of  advertisements  were  tested  with  a  total  of 
161  subjects,  69.  men  and  92  women.  The  sets  of  advertise- 
ments were  as  follows:  4  half-page  advertisements  of  the 
American  Collection  Service,  Detroit,  Mich.,  procured  from 
Mr.  William  A.  Shryer;  10  full-page  advertisements  of  the 
American  Collection  Service;  9  quarter-page  advertisements, 
Saturday  Evening  Post  size,  of  the  Burroughs  Adding  Machine 
Co.,  obtained  from  Mr.  William  A.  Hart  of  the  advertising 
department  of  the  Burroughs  Company. 

The  following  data  concerning  the  American  Collection 
Service  advertisements  were  furnished:  the  number  of  in- 
sertions, the  total  number  of  inquiries,  the  advertising  cost, 
the  cost  per  inquiry  and  the  profit  or  loss  for  each  advertise- 
ment. 

From  the  Burroughs  Adding  Machine  Co.  the  following 
data  were  received  concerning  each  advertisement:  the 
number  of  inquiries,  the  number  of  trials,  the  number  of 
sales,  the  total  amount  received  from  the  sales. 

From  these  data,  it  should  be  possible  to  determine  with 
some  accuracy  which  of  the  advertisements  was  of  the  greatest 
value  from  the  business  standpoint.  The  settling  of  this 
question  is,  however,  more  complicated  than  appears  on  the 
surface.  Any  one  of  the  points  mentioned  may  be  considered 
as  a  test  of  efficiency.  The  trouble  is  that  they  may  not  agree 
to  any  remarkable  extent.  To  indicate  this,  the  various 
measurements  are  put  in  the  form  of  tables  which  will  show 
the  order  of  merit  according  to  the  different  standards.  In 
the  tables  throughout  the  paper,  number  I  indicates  that  the 
advertisement  so  designated  was  the  best  from  the  stand- 
point of  the  standard  used;  number  2,  that  it  was  in  second 

place,  etc. 

AMERICAN  COLLECTION  SERVICE 

Half-Page  Advertisements 


Ad. 

Average  Number  of  Inquiries 

Cost  per  Inquiry 

Profit 

A,  . 

I 

I 

I 

B  

2 

3 

2 

c 

2 

4 

D  

4 

4 

3 

406 


H.  F.  ADAMS 


Full-Page  Advertisements 


E.. 

•z 

•J 

6 

F  

10 

0 

c 

G  . 

6 

H       ..      . 

g 

c 

7 

/ 

4~ 

2 

2 

T 

8 

7 

•j 

L" 

7 

8 

IO 

M 

IO 

8 

N 

I 

I 

i 

0  

2 

4 

4 

BURROUGHS  ADDING  MACHINE  Co. 


Ad. 

Inquiries 

Trials 

Sales 

Amount 

1872  A  .  .  .  .                .... 

c 

4. 

2 

2 

1702  A 

•j 

2 

•5 

•» 

1803   ^ 

x 

7 

6 

1804  ^  

6 

6 

8 

0 

1820  A  

2 

-i 

r 

1832  A.  . 

8 

c 

7 

7 

184.4.  A 

7 

6 

A 

1870  A 

8 

8 

1883  ^  

I 

i 

i 

i 

It  is  evident  from  these  tables  that  the  measurement  of 
efficiency  which  is  used  is  of  some  importance.  The  coef- 
ficient of  correlation1  between  the  orders  as  established  by 
the  various  possible  measurements  will  show  their  resemblance. 

AMERICAN  COLLECTION  SERVICE 

Correlation  between 

Half  Page      Full  Page 

Inquiries  and  cost  per  inquiry 80  .915 

Inquiries  and  profit 80  .430 

Cost  per  inquiry  and  profit 40  .624 

BURROUGHS  ADDING  MACHINE  Co. 

Correlation  between 

Quarter  Page 

Inquiries  and  trials 790 

Inquiries  and  sales 834 

Inquiries  and  amount 650 

Trials  and  sales 773 

Trials  and  amount 617 

Sales  and  amount 933 

These  figures  indicate  that  the  busines  test  which  is  used 
has  a  considerable  influence  on  the  coefficient  of  correlation 

1  The  coefficients  of  correlation  are  worked  out  by  the  formula  given  by  Myers, 
'Text  Book  of  Experimental  Psychology,'  1909,  page  131.  The  formula  is  r  =  I 
-[6  sigma  (rf)Vn(n»— i)]. 


TESTS  IN  ADVERTISING 


407 


between  it  and  the  laboratory  test.  For  reasons  which  will  be 
explained  more  fully  in  a  later  part  of  the  paper,  it  appears 
that  the  average  number  of  inquiries  per  insertion  of  the  ad- 
vertisment  is  the  fairest  measure  of  the  pulling  power  of  the 
advertisement  under  actual  business  conditions.  This  meas- 
ure was  taken  because  it  seems  to  be  the  fairest  test  of  the 
actual  pulling  power,  undisturbed  by  such  things  as  a  follow- 
up  system,  the  arguments  of  salesmen,  etc. 

The  experiment  was  carried  on  as  follows.  The  subject 
was  handed  a  series  of  advertisements  and  told  to  look  them 
over  carefully.  Having  become  familiar  with  them,  he  was 
instructed  to  pick  out  the  one  which  was  to  him  the  most 
persuasive.  By  persuasive  was  meant  the  one  which  would 
be  most  likely  to  make  him  answer  the  advertisement.  This 
done,  he  was  asked  to  pick  out  the  second  best,  the  third,  and 
so  on,  until  he  had  the  series  arranged  in  a  descending  order 
from  the  most  persuasive  to  the  least  persuasive.  A  first 
choice  was  given  a  credit  of  I,  the  next  best  a  credit  of  2  and 
so  on  down  throughout  the  entire  series.  When  the  161  sub- 
jects had  arranged  the  set  of  advertisements,  the  credits 
which  each  advertisement  had  received  were  added  and  di- 
vided by  161,  thus  giving  the  average  place  which  the  adver- 
tisement occupied  in  the  opinion  of  the  161  subjects.  The 
one  which  received  the  smallest  average  was  considered  to 
have  the  greatest  pulling  power;  the  one  which  obtained  the 
largest  average  was  credited  with  the  least  pulling  power. 

In  the  tables  below  are  given  the  averages  for  each  ad- 
vertisement as  worked  out  in  this  way,  together  with  the 
average  deviation  (A.  D.).  The  reactions  of  the  men  and  of 
the  women  are  not  given  separately,  for  no  significant  differ- 
ences were  found. 

AMERICAN  COLLECTION  SERVICE 
Half  Page 


Ad. 

Average 

A.  D. 

Position 

A                    

1.84 

0.74 

I 

B  

1.93 

0.84 

2 

c  

2.8l 

0.81 

3 

D  

3-31 

0-75 

4 

408 


E.  F.  ADAMS 


Full  Page 


E 

6.13 

2  "?! 

F 

4.4.7 

^.31 
2  6Q 

•3 

G 

6  OO 

2  OO 

| 

H 

4.  83 

2IQ 

I 

6.78 

214. 

] 

5  18 

2  Tl 

i:::::::::;:::::::: 

£2 

6.6O 

•*"*j 
I.Q7 

g 

M 

412 

2  2O 

N  

7.71 

1.  80 

IO 

0  

2.98 

1.67 

I 

BURROUGHS  ADDING  MACHINE  Co. 


Ad. 

Average 

A.  D. 

Position 

I 

3-95 

1-93 

2 

2 

6.87 

1.88 

9 

3 

4-54 

2-34 

5 

4 

4.52 
6.70 

2.02 
1.92 

8 

6 

4.00 

1.89 

3 

7 

5-32 

2.42 

6 

8 

6.37 

1.77 

7 

9 

3-71 

1.72 

i 

The  tables  show  that  a  more  or  less  definite  order  of  the 
relative  persuasiveness  of  the  advertisements  in  these  three 
sets  has  been  worked  out.  The  average  deviations  indicate 
that  some  changes  in  order  might  occur  if  more  subjects  were 
tested,  but  the  extremes  at  least  are  fairly  well  defined. 

As  a  check  upon  the  probability  of  the  final  order  of  the 
series  as  determined  by  the  experiment,  the  following  method 
was  used.  The  order  was  determined  by  averaging  the 
results  of  the  first  10  subjects,  then  of  the  first  20  and  these 
orders  compared.  Then  the  order  of  the  first  20  and  the  first 
30  was  compared,  and  so  on  for  the  161  subjects.  If  the  final 
order  was  established  relatively  early  in  the  series  and  per- 
sisted without  actual  change  throughout,  it  was  thought  that 
the  final  order  had  a  high  degree  of  probability.  The 
question  of  the  number  of  subjects  necessary  in  an  experiment 
of  this  sort  is  always  an  important  one  and  one  which  it  is 
difficult  to  settle  off-hand.  Such  a  test  as  the  one  described 
is  an  entirely  practical  measurement  which  can  be  applied 
at  any  time  in  the  experiment. 

It  was  found  that  the  final  order  of  the  half-page  adver- 
tisements of  the  American  Collection  Service  was  determined 


TESTS  IN  ADVERTISING  4°9 

with  30  subjects.  The  addition  of  130  more  did  not  change 
the  relative  order  of  merit,  though,  obviously,  there  were 
changes  in  the  degree  of  merit.  Advertisements  A  and  #, 
even  at  the  end  of  the  160  trials,  might  have  been  changed 
by  the  addition  of  the  results  of  10  more  subjects  if  they  had 
all  given  A  fourth  place  and  B  first  place.  In  the  entire 
experiment,  however,  A  was  put  in  fourth  place  only  10  times, 
so  the  chances  of  its  appearing  in  last  place  are  I  to  16.  In 
the  same  way,  the  chances  of  B  appearing  in  first  place  are 
I  to  2.4.  We  are  justified  in  concluding,  then,  that  the  final 
order  of  this  series  is  determined  beyond  reasonable  doubt 
for  the  class  of  subjects  used. 

With  the  full-page  advertisements  of  the  American  Col- 
lection Service,  the  final  order  was  determined  by  the  i2Oth 
trial.  The  addition  of  the  next  40  subjects  did  not  affect  the 
relative  order.  The  probable  accuracy  of  this  series,  while 
not  so  great  as  that  of  the  half-page  series,  is  sufficient  for  all 
practical  purposes.  Some  of  the  advertisements  in  the 
middle  of  the  series  might  have  shifted  one  place  by  the  ad- 
dition of  10  more  subjects,  but  this  is  unlikely,  for  in  order 
to  do  so,  the  ten  would  have  to  give  averages  which  were  not 
even  approached  in  the  course  of  the  experiment.  So  we 
may  conclude  that  we  have  obtained  here  an  order  which 
would  be  very  closely  approximated  by  any  laboratory  test 
conducted  upon  average  undergraduates. 

With  the  Burroughs  Adding  Machine  advertisements,  it 
may  be  said  a  satisfactory  final  order  never  was  obtained. 
An  order  was  established  with  the  i2Oth  trial  which  lasted 
through  the  isoth,  but  the  difference  between  the  credits  for 
two  of  the  advertisements  was  so  slight  that  they  were  inverted 
with  the  addition  of  the  next  ten  subjects.  Two  other  ad- 
vertisements in  the  series  might  well  have  been  inverted  by 
the  addition  of  another  10  subjects.  So  we  may  say  that  an 
entirely  satisfactory  final  order  never  was  determined  for 
this  set  of  advertisements.  The  extremes  are  clearly  defined, 
but  the  intermediate  members  of  the  series  are  somewhat 
variable.  It  seems  probable,  in  view  of  these  facts,  that  this 
series  of  advertisements  was  of  a  more  even,  homogeneous 


410 


H.  F.  ADAMS 


sort  than  was  either  of  the  series  of  the  American  Collection 
Service.  This  does  not  necessarily  mean  that  the  Burroughs 
Adding  Machine  advertisements  are  either  better  or  worse 
than  the  American  Collection  Service  series.  It  simply 
means  that  it  was  more  difficult  to  make  adequate  judgments 
between  them. 

This  general  condition  emphasizes  one  fact  which  must  be 
plainly  apparent  to  any  student  of  the  psychology  of  adver- 
tising,— namely,  that  our  laboratory  tests  have  been  unable 
to  tell  us  whether  an  advertisement  is  absolutely  a  good  ad- 
vertisement or  not.  The  only  thing  such  a  test  can  do  is  to 
place  it  relatively  in  a  series.  The  limits  of  goodness  and 
badness  are  to  be  found  inside  of  that  particular  series. 
Because  one  advertisement  is  the  first  of  one  series  and  an- 
other the  last  in  a  second  is  no  reason  for  asserting  that  the 
former  is  absolutely  a  better  advertisement  than  the  latter. 

AMERICAN  COLLECTION  SERVICE. 
Half  Page. 


Ad. 

Order  as  Determined  by 

Lab.  Test 

Inquiries 

Cost  per  Inq. 

Profit 

A 

I 

2 
3 

4 

I 
2 

3 
4 

I 

3 

2 

4 

I 

2 

4 

3 

B 

c 

D  

The  following  coefficients  of  correlation  are  found  to  exist: 

Between  the  laboratory  test  and  the  number  of  inquiries I. CO 

"          "          "  "       "    the  cost  per  inquiry 80 

"       "    the  profit 80 

AMERICAN  COLLECTION  SERVICE 
Full  Page 


Order  as  Determined  by 


Ad. 

Lab.  Test 

Inquiries 

Cost  per  Inq. 

Profit 

E.. 

•j 

6 

F  

•7 

IO 

Q 

G  

6 

r 

I 

H  

A 

I 

/  

2 

2 

/.  . 

C 

8 

7" 

•3 

£.. 

8 

7 

8 

IO 

M  

2 

IO 

8 

N  

IO 

I 

i 

i 

0  

I 

2 

4 

4 

TESTS  IN  ADVERTISING 


411 


The  following  coefficients  of  correlation  are  found  to  exist: 


Between  the  laboratory  test  and  the  number  of  inquiries , 
"      ««    the  cost  per  inquiry... 
"      "    the  profit 


.—043 
.—0.58 

.— O.OI 


BURROUGHS  ADDING  MACHINE  Co. 


Order  as  Determined  by 


Ad. 

Lab.  Test 

Inquiries 

Amount  Received 

I 
2 

2 

9 

3 
4 

I 

3 

5 

5 

2 

4 

4 

6 

9 

5 

8 

2 

5 

6 

3 

7 

4 

7 

6 

i 

i 

8 

7 

8 

7 

9 

i 

9 

8 

The  following  coefficients  of  correlation  were  found  to 
exist: 

Between  the  laboratory  and  test  the  number  of  inquiries — 0.43 

"          "          "  "      "    the  amount  received —0.06 

The  second  step  in  the  experiment  is  to  compare  the  order 
as  determined  by  the  laboratory  experiment  with  the  order 
as  determined  by  the  different  measures  of  business  efficiency. 
This  comparison  is  given  in  the  preceding  tables. 

Taking  these  three  sets  of  results,  we  find  the  following 
correlations  between  the  order  as  determined  by  the  laboratory 
test  and  the  order  as  determined  by  the  average  number  of 
inquiries. 

Half-page  advertisements,  A.  C.  S =     l.oo 

Full-page  advertisements,  A.  C.  S = — 0.43 

One-fourth-page  advertisements,  B.  A.  M = — 0.43 

Average =     0.047 

We  also  find  the  following  correlations  between  the  order 
of  merit  as  -determined  by  the  laboratory  test  and  the  order 
determined  by  the  profit  or  the  amount  received. 

Half-page  advertisements,  A.  C.  S =     0.80 

Full-page  advertisements,  A.  C.  S = — o.oi 

One-fourth-page  advertisements,  B.  A.  M =  —0.06 

Average =  +0.243 


412  H.  F.  ADAMS 

These  figures  show  simply  chance  resemblance  between  the 
results  of  the  laboratory  test  and  the  average  number  of 
inquiries  per  insertion  and  very  little  better  than  chance  re- 
semblance between  the  laboratory  test  and  the  business  test 
where  profits  are  used  as  the  measure.  The  indication  is 
that  the  order  of  merit  method  has  at  least  no  universal 
application  to  advertising  problems.  Of  course,  not  enough 
series  of  advertisements  have  been  tested  to  settle  the 
question  definitely.  But  since  two  of  the  three  tests  made 
have  shown  a  significant  negative  correlation,  a  fairly  large 
number  of  tests  which  result  in  equally  strong  positive 
correlations  will  be  necessary  to  offset  the  negative  results  of 
these  experiments. 

It  is  possible,  too,  that  college  students  are  not  satisfactory 
subjects  for  the  kinds  of  advertisements  which  were  used. 
Since  a  fairly  large  percentage  of  the  men  go  into  business 
upon  leaving  college,  they  are  possibly  more  satisfactory  than 
would  appear  at  first. 

As  will  be  seen  below,  advertisement  N  of  the  American 
Collection  Service  series  present  some  queer  anomalies.  Even 
if  this  advertisement  is  left  entirely  out  of  consideration,  the 
coefficient  of  correlation  between  the  laboratory  test  and  the 
business  test  as  measured  by  the  average  number  of  inquiries 
is  —  0.12. 

The  general  conclusion  seems  to  be  that  the  mail  order 
business  appeals  to  a  special  and  limited  class  of  individuals. 
College  students,  on  the  average,  are  not  fair  representatives 
of  such  a  class.  With  a  mail-order  business,  it  is  possible  to 
get  returns  which  are  extremely  accurate,  so  such  advertise- 
ments would  make  the  best  material  for  laboratory  tests, 
if  such  tests  would  only  work.  On  the  other  hand,  it  does 
seem  probable  that  the  order  of  merit  method  might  be  applied 
to  those  commodities  which  are  in  more  general  demand,  such 
as  soaps,  foods,  and  the  like.  It  is,  however,  impossible  to 
get  accurate  returns  as  to  the  exact  amount  of  business  which 
each  advertisement  has  brought  in.  This  renders  it  impossible 
to  be  sure  that  the  laboratory  test  actually  has  a  high  coef- 
ficient of  correlation  with  the  business  returns. 


TESTS  IN  ADVERTISING  413 

There  are  several  interesting  things  which  crop  out  in 
connection  with  the  advertisements  of  the  American  Collec- 
tion Service.  It  will  be  recalled  that  Mr.  Shryer  furnished 
two  sets  of  advertisements,  one  consisting  of  four  half-page, 
the  other  of  ten  full-page,  advertisements.  Half-page  ad- 
vertisement D  was,  as  far  as  possible,  an  exact  copy  of  full- 
page  advertisement  N.  In  N  there  were  five  pictures  in 
connection  with  testimonials,  and  a  return  coupon.  In  the 
half-page  advertisement  D  there  were  but  three  pictures 
accompanying  testimonials,  and  no  return  coupon.  The 
wording  of  the  argument  in  the  two  advertisements  was  as 
nearly  identical  as  possible  considering  the  change  in  size. 
In  fact,  only  6  words  were  changed.  The  half-page  adver- 
tisement, however,  was  printed  in  smaller  type,  as  necessarily 
must  be  the  case,  considering  the  difference  in  size. 

In  spite  of  the  great  similarity  of  the  two  advertisements, 
the  results  of  the  business  returns,  taking  the  average  number 
of  inquiries  as  the  basis,  show  that  the  full-page  advertisement 
N  was  the  best  of  the  set  of  ten.  The  half  page  advertisement 
D  was  the  poorest  one  of  its  set.  With  such  discrepancies  as 
this  in  the  business  returns,  it  would  be  truly  remarkable  if 
the  laboratory  test  did  show  a  high  coefficient  of  correlation 
with  the  business  test.  The  laboratory  test  is  at  least  fairly 
consistent,  for  it  ranked  each  of  the  advertisements,  D  and  TV, 
as  last  of  the  set  to  which  it  belonged. 

In  the  business  test,  the  presence  of  the  return  coupon 
in  one  advertisement  and  its  absence  in  the  other  may  have 
been  a  determining  factor.  Shryer1  ran  two  half-page  ad- 
vertisements at  different  times  which  were  just  alike  except 
that  one  had  a  return  coupon,  the  other  did  not.  The  one  with 
the  return  coupon  brought  83  replies,  the  other  41,  showing 
that  in  this  particular  case,  the  use  of  the  return  coupon 
more  than  doubled  the  number  of  inquiries.  If  N  had 
brought  only  half  as  many  replies,  it  would  have  ranked  sixth 
in  the  series,  while  if  D  had  brought  in  double  the  number  of 
replies,  it  would  have  ranked  second.  However,  if  there  is 
so  great  an  increase  in  efficiency  coming  from  the  return 

1 W.  A.  Shryer,  System,  December,  1913,  p.  579. 


41 4  H.  F.  ADAMS 

coupon,  the  laboratory  returns,  if  they  are  adequate,  should 
have  indicated  it. 

It  so  happened  that  there  was  a  great  similarity  between 
two  other  members  of  the  two  sets.  Half-page  advertisement 
B  was  very  much  like  full-page  advertisement  0.  The  word- 
ing was  practically  the  same,  though  different  pictures  were 
used.  On  the  basis  of  the  average  number  of  inquiries  per 
insertion,  B  was  in  second  place.  According  to  the  laboratory 
test,  it  was  second  in  the  set  of  half-page  advertisements. 
From  the  standpoint  of  business  returns,  full-page  advertise- 
ment 0  was  in  second  place;  in  the  laboratory  test,  it  was  first. 
This  shows  a  fair  consistency  for  both  the  laboratory  test  and 
the  business  test. 

The  similarity  between  the  returns  from  B  and  0  is  an 
interesting  check  upon  the  dissimilarity  found  to  exist  between 
D  and  N.  For  it  might  have  been  thought  that  the  half- 
page  advertisements  were  much  superior  in  general  make-up 
and  appeal  to  the  full-page  advertisements.  Logically,  D 
might  easily  have  been  the  worst  of  the  half-pages,  while  its 
duplicate  N  might  equally  well  have  been  the  best  of  the  full- 
page  displays.  This,  however,  is  rendered  extremely  doubtful 
by  the  results  obtained  from  B  and  0.  The  indication  is  that 
the  peculiar  results  obtained  with  D  and  N  are  due  to  ex- 
traneous conditions  which  could  not  possibly  be  controlled 
in  the  laboratory. 

Because  of  the  results  of  this  experiment  as  well  as  on 
account  of  theoretical  considerations,  the  writer  has  been  led 
to  question  the  application  of  the  order  of  merit  method  to 
advertising  problems.  He  does  not  question  the  true  useful- 
ness of  the  method,  but  does  deplore  the  uses  to  which  it  has 
been  put.  In  his  opinion,  the  experiments  which  have  been 
performed  by  this  method  on  advertising  problems  can  be 
attacked  on  several  sides. 

In  the  first  place,  the  experimenters  have  in  but  a  very  few 
instances  compared  the  laboratory  results  with  the  business 
results.  The  idea  of  this  comparison  is,  of  course,  to  show 
the  dependability  of  the  method  as  a  laboratory  technique  for 
investigating  advertising  problems.  One  thing  which  has  been 


TESTS  IN  ADVERTISING  415 

done  is  to  compare  the  order  as  determined  by  the  laboratory 
experiment  with  the  order  as  determined  by  the  opinion  of 
certain  selected  advertising  experts,  who  were  practically 
put  through  the  same  experiment.  Since  Dr.  E.  K.  Strong, 
Jr.,  was  one  of  the  first  to  apply  this  method  to  the  psychology 
of  advertising,  a  quotation  from  one  of  his  articles  will  be 
appropriate  in  bringing  out  the  point.  "It  is  scarcely 
necessary  to  repeat  that  the  results  of  the  Packer  Manu- 
facturing Company  are  not  based  upon  carefully  compiled 
data,  but  only  upon  the  judgment  of  the  firm  based  on  their 
business  experience.  Any  one  familiar  with  advertising  knows 
that  such  data  have  not  been  compiled  for  any  extensive  set 
of  advertisements,  let  alone  a  series  of  fifty  extending  over 
twenty  years  of  service.  If  such  data  did  exist,  it  could  not 
be  used  at  its  full  face  value,  as  an  advertisement  of  twenty 
years  ago  might  have  been  very  effective  then  and  be  out  of 
date  to-day. 

"The  order  of  the  twenty-five  subjects  correlates  plus  .52 
with  the  order  of  either  of  the  two  advertising  experts.  The 
correlations  between  the  orders  of  the  two  advertising  experts 
is  plus  .64.  These  relationships  are  lower  than  those  which 
have  been  obtained  with  other  sets  of  advertisements.  .  .  . 

"It  is  evident,  then,  that  the  *  order  of  merit  method'  does 
give  results  that  correlate  high  with  results  obtained  in 
business."1 

Since  by  results  obtained  in  business,  Strong  must  evi- 
dently mean,  in  the  above  connection,  the  opinion  of  adver- 
tising experts,  another  quotation  taken  from  the  same 
writer,  but  in  a  different  article,  will  be  especially  interesting. 
"At  the  present  time  there  is  no  way  of  estimating  which  are 
the  good  and  which  are  the  poor  advertisements  except  on 
the  basis  of  personal  judgment;  and  when  the  reviews  and 
criticisms  of  different  advertising  men  are  compared,  it  is 
apparent  that  this  personal  judgment  is  today  a  very  variable 
factor."2 

The  second  quotation  robs  the  first  of  whatever  force  it 
might  originally  have  had. 

1  Strong,  Jour,  of  Phil.,  Psy.,  etc.,  VIII.,  603,  604. 

2  Strong,  Jour.  Ed.  Psy.,  IV.,  393. 


41 6  H.  F.  ADAMS 

In  order  to  be  of  any  particular  value,  the  correlation 
between  the  business  test  and  the  laboratory  test  must  be 
worked  out  with  actual  business  returns.  These  are  obtain- 
able for  but  few  kinds  of  commodity,  since  they  depend  upon 
elaborate  systems  of  keying.  In  order  to  have  the  keying 
satisfactory,  all  orders  must  eventually  come  to  a  head  office, 
labeled  in  such  a  way  that  each  advertisement  may  receive 
full  credit  for  its  work.  Such  a  thing  is  an  obvious  impossi- 
bility with  such  products  as  soaps,  foods,  and  in  general  those 
things  which  are  procurable  at  stores. 

The  advertisements  which  can  be  accurately  keyed  are 
ordinarily  mail  order  propositions.  With  any  adequate 
system  of  checking  returns,  it  is  possible  to  figure  out  from 
keyed  advertisements  the  following  things:  the  average 
number  of  inquiries  per  insertion,  the  average  cost  per  in- 
quiry, the  total  number  of  sales,  the  profit  or  loss.  Some  of 
these  returns  obviously  depend  upon  other  things  than  the 
advertisement  itself,  but  it  was  the  advertisement  which 
started  the  whole  process  going. 

Which  of  these  is  the  fairest  measure  of  the  pulling  power 
of  the  advertisement?  The  number  of  inquiries  indicates 
the  number  of  persons  who  were  influenced  sufficiently  by  the 
appeal  to  be  incited  to  action.  The  weakness  of  this  method 
is  that  the  position  of  the  advertisement  on  the  page1  or  the 
position  of  the  page2  in  the  advertising  section  of  the  magazine 
may  be  detrimental.  The  same  advertisement  in  some  other 
position  might  have  pulled  many  more  inquiries.  Again,  the 
time  of  year  is  a  very  important  matter.  There  are  good 
seasons  and  bad  seasons.3  General  economic  conditions, 
national  or  sectional  eras  of  prosperity  are  also  modifying 
factors. 

1  Hollingworth,  'Advertising  and  Selling/  80-90. 

2  Starch,  'Advertising,'  106-116. 

«  Shryer,  'Analytical  Advertising,'  167-170.  Shryer  says,  on  p.  169:  "As  a  whole, 
however,  it  may  be  said  that  the  three  largest  months  of  practically  every  year  are 
January,  February  and  March." 

See  also  Starch,  'Advertising,'  p.  50.  The  table  at  the  bottom  of  the  page  shows 
that,  for  the  commodity  mentioned,  more  advertising  was  run  and  more  sales  were 
made  during  the  first  half  of  the  year  than  during  the  last  half.  Another  table,  given 
by  Starch  on  p.  93,  indicates  that  the  most  advertising  is  carried  in  May  and  December; 
the  least  in  January  and  August. 


TESTS  IN  ADVERTISING  417 

It  seems  obvious  that  the  natural  procedure  in  such  cases 
would  be  to  repeat  the  advertisement  enough  times  in  different 
parts  of  the  magazine  and  at  different  times  selected  to  take 
account  of  seasonal  differences  and  so  on.  The  objection  is 
that  with  successive  appearances  of  the  advertisement  there 
is  a  fairly  constant  and  regular  decrease  in  the  number  of 
inquiries.1  However,  if  enough  advertisements  were  used  in 
this  way,  either  the  total  or  the  average  number  of  inquiries 
would  be  a  sufficiently  satisfactory  measure  of  the  pulling 
power  of  the  advertisement.  It  is,  in  fact,  the  only  obtain- 
able measure  of  the  pulling  power  uncomplicated  by  other 
factors. 

A  second  possibility  is  the  average  cost  per  inquiry.  This 
method  is  open  to  all  of  the  objections  noted  above,  and  to  a 
still  further  one.  The  actual  cost  of  the  space  occupied  by 
the  advertisement  does  not  in  any  way  directly  effect  the 
excellence  of  the  advertisement  itself.  Even  in  the  same 
medium,  the  charge  per  page  is  liable  to  sudden  shifts.  It  is 
unfair  to  the  advertisement  to  make  it  suffer  the  handicap 
of  the  increased  rate.  The  amount  charged  per  page  is  not  an 
accurate  measurement  of  the  circulation  of  the  medium  and 
so  an  approximation  of  the  number  of  persons  who  may  read 
the  advertisement. 

The  number  of  sales  is  obviously  unfair,  for  we  have  to  do 
there  not  only  with  the  advertisement  itself,  but  with  the 
goodness  or  badness  of  the  follow-up  system,  the  efficiency 
of  salesmen,  etc.  Some  of  the  blame  may  be  laid  to  the  ad- 
vertisement for  it  may  have  been  constructed  in  such  a  way 
as  to  have  interested  many  who  could  not  possibly  have  bought 
that  line  of  goods.  Or  they  have  been  misled  by  the  adver- 
tisement and  when  they  found  out  what  the  product  was  from 
the  follow-up  system,  they  lost  interest. 

The  question  of  profit  or  loss  resulting  from  the  use  of  a 
certain  advertisement,  while  of  considerable  interest  to  the 
business  man,  is  still  not  a  test  of  the  pulling  power  of  the 
advertisement,  but  is  a  measure  of  the  pulling  power  as  modi- 

1  Shryer,  'Analytical  Advertising,'  8l  ff.,  220-223.  Starch,  'Advertising,'  170-179. 
Hollingworth,  'Advertising  and  Selling,'  235.  Strong,  PSY.  REV.,  XXL,  147. 


418  H.  F.  ADAMS 

fied  by  the  cost  of  the  advertisement  and  the  adequacy  of  the 
follow-up  system. 

Taking  it  all  in  all,  the  average  number  of  inquiries  per 
insertion  seems  to  be  the  fairest  test  of  the  actual  pulling  power 
of  the  advertisement.  It  is,  then,  the  measurement  which 
should  be  used  in  endeavoring  to  obtain  the  correlation 
between  the  orders  of  the  business  test  and  the  laboratory 
test. 

Another  criticism  of  the  order  of  merit  method  as  it  has 
often  been  used  is  on  the  ground  of  the  number  of  subjects 
employed  or  the  number  of  tests  made.  Obviously,  if  rela- 
tively few  additional  tests  will  change  the  order  of  the  ad- 
vertisements in  the  series,  the  experiment  is  unfinished. 

From  the  experiments  discussed  above,  it  appears  that  the 
number  of  tests  necessary  depends  upon  at  least  two  factors. 
In  the  first  place,  the  actual  amount  of  difference  in  terms  of 
judgment  steps  between  the  contiguous  advertisements  in 
the  series  is  an  important  consideration.  With  advertise- 
ments far  apart,  where  the  judgment  is  easy  to  make,  the 
order  will  be  established  with  relatively  few  subjects.  But, 
as  the  judgments  become  more  and  more  difficult,  an  in- 
creasing number  of  tests  will  be  necessary.  Secondly,  the 
number  of  advertisements  in  the  series  will  be  a  determining 
factor.  For  as  we  increase  the  number  of  advertisements  in 
the  series,  we  ordinarily  must  necessarily  decrease  the 
judgment  steps,  thus  rendering  a  satisfactory  arrangement 
more  difficult. 

Shryer1  who  was  the  first  to  use  any  considerable  number 
of  persons  in  an  advertising  experiment,  employed  a  total  of 
508  in  his  efforts  to  reach  practical  certainty.  In  the  most 
complex  of  his  experiments,  in  which  the  method  of  paired 
comparisons  was  used,  the  final  order  was  obtained  at  the 
3OOth  trial.  The  addition  of  200  more  subjects  left  the 
relative  order  of  the  advertisements  in  the  series  unchanged. 
In  this  experiment  he  used  but  five  different  advertisements. 
Had  he  used  more  than  five,  ten  for  example,  he  probably 
would  have  had  to  employ  a  great  many  more  individuals 

1  Shryer,  System,  XXV.,  146. 


TESTS  IN  ADVERTISING  419 

before  obtaining  a  satisfactory  final  order.  To  be  sure,  his 
material  was  such  that  there  was  a  great  chance  for  varia- 
bility of  response,  but  this  is  true  of  practically  all  experiments 
carried  on  in  the  field  of  advertising. 

Since  Shryer,  in  his  experiment,  used  the  method  of  paired 
comparisons,  his  results  are  not  strictly  applicable  here.  The 
experiments  which  have  been  described  in  this  paper  indicate 
something  about  the  number  of  tests  necessary.  With  four 
advertisements  in  the  series,  the  final  order  was  determined 
with  30  trials;  with  ten  advertisements,  the  final  order  was 
determined  with  120  trials.  With  three  other  sets  of  ten  ad- 
vertisements each,  which  were  used  to  test  a  different  point,  a 
satisfactory  final  order  was  not  obtained  with  100  trials. 
Until  enough  data  have  been  obtained  to  work  out  a  satis- 
factory mathematical  law,  it  seems  that  one  of  the  tests  of 
an  adequate  number  of  subjects  is  the  purely  practical  one 
which  was  given  in  the  first  part  of  this  paper.  Enough  has 
been  said,  however,  to  indicate  that  in  the  majority  of  tests, 
an  insufficient  number  of  subjects  has  been  used. 

The  next  point  to  be  considered  is  whether  the  order  of 
merit  method  can  be  used  to  determine  the  relative  pulling 
power  of  a  series  of  advertisements.  Before  considering  this 
point  theoretically,  we  may  repeat  that  the  experiments  which 
have  been  designed  and  carried  on  to  test  the  correlation 
between  the  laboratory  and  the  business  test  have  sometimes 
shown  correlations  as  high  as  plus  i.oo  and  sometimes  as  low 
as  —  0.60.  It  would  seem,  then,  that  sometimes  the  method 
will  work  and  sometimes  it  will  not. 

The  instructions  usually  given  in  the  experiment  are, 
"Sort  these  advertisements  according  to  the  order  in  which 
you  would  buy  the  .  .  .  ."  That  means  that  every  individual 
who  performs  the  experiment  makes  a  definite  arrangement 
of  the  advertisements,  the  order  showing  the  persuasiveness 
as  far  as  he  is  concerned.  The  assumption  is  that  from  his 
arrangement  of  the  advertisements,  it  is  possible  to  tell  which 
one  made  him  buy  the  article,  for  each  one  experimented  upon 
is  evidently  regarded  as  a  purchaser.  There  is,  unfortun- 
ately, no  way  of  telling  which  of  the  persons  experimented 


420  H.  F.  ADAMS 

upon  would,  in  actual  life,  be  sufficiently  interested  in  any  of 
the  advertisements  in  the  series  to  make  him  purchase  the 
commodity. 

In  business,  the  situation  is  quite  different.  The  following 
figures,  taken  from  Shryer,1  will  point  out  what  is  likely  to 
happen  in  a  mail-order  business.  "  Let  us  assume  a  circulation 
of  100,000  at  $100  a  page — an  honest  rate.  Let  us  use  a 
page  of  the  strongest  copy,  yielding  inquiries  at  10  cents.  Let 
us  assume  a  selling  average  of  20  per  cent.,  just  double  the 
ordinary.  We  therefore  secure  1,000  inquiries.  We  there- 
fore sell  200  of  the  100,000  or  one-fifth  of  I  per  cent.  .  .  . 
These  figures  are  assumed  figures,  but  they  represent  the 
outside  limits  of  actual  average  results."  These  figures 
indicate  that  on  the  average  the  inquiries  are  I  per  cent,  of 
the  circulation  of  the  magazine.  It  has  been  estimated  that 
five  persons  read  each  magazine.  There  is,  then,  a  possibility 
that  the  advertisement  will  be  seen  by  500,000  persons. 
The  estimate  of  the  number  of  persons  who  see  the  ad- 
vertisements varies  from  10  per  cent,  to  50  per  cent,  of  the 
readers  of  the  magazine.  If  we  take  the  lower  limit,  10  per 
cent.,  that  means  that  50,000  will  see  some  of  the  advertise- 
ments. The  proportion  which  will  see  a  particular  advertise- 
ment is  pure  guess  work.  As  a  working  basis,  we  will  take 
20  per  cent.  That  means  that  10,000  will  see  the  advertise- 
ment, and  a  thousand  will  be  sufficiently  interested  in  it  to 
reply,  or  10  per  cent.  A  great  many  of  the  other  90  per  cent, 
who  do  not  inquire  are  almost  interested  enough  to  do  so,  still 
more  are  slightly  interested,  others  are  indifferent,  while  still 
others  get  a  negative  reaction.  Therefore,  the  results  ob- 
tained from  the  mail-order  business  test  are  got  from  a  very 
small  percentage  of  the  total  number  of  readers.  The  results 
obtained  from  the  laboratory  test  are  arrived  at  by  using  the 
results  of  the  whole  100  per  cent,  of  readers,  instead  of  the 
IO  per  cent,  who  would  on  the  average  be  interested  enough 
to  answer  the  advertisement.  The  using  of  the  other  90 
per  cent,  of  the  persons  introduces  factors  into  the  experiment 
which  would  quite  certainly  modify  the  results  so  that  they 

1  Shryer,  'Advertising  and  Selling,'  XXIL,  24. 


TESTS  IN  ADVERTISING  421 

would  not  adequately  express  the  normal  results  for  the  10 
per  cent.  If  we  only  had  some  way  of  determining,  in  our 
laboratory  experiments,  the  individuals  who  make  up  the  10 
per  cent,  who  are  sufficiently  interested,  we  probably  could 
arrive  at  fairly  dependable  results. 

It  must  be  kept  in  mind  that  a  mail-order  business  appeals 
to  a  very  small  number  of  persons  at  best.  The  same  general 
situation  exists,  also,  with  regard  to  the  more  expensive  com- 
modities, such  as  pianos  and  vacuum  cleaners.  Such  ad- 
vertisements certainly  appeal  to  a  very  small  and  select  class. 
Consequently,  it  is  doubtful  if  adequate  experiments  could  be 
performed  upon  advertisements  of  these  commodities  in  the 
laboratory.  The  cheaper,  more  frequently  used  goods,  such 
as  foods,  soaps,  etc.,  very  probably  could  be  tested  adequately 
if  there  were  any  way  of  determining  accurately  the  actual 
business  returns. 

Lastly,  it  is  extremely  doubtful  if  the  great  majority  of 
individuals  can  tell  which  of  a  series  of  advertisements  would 
be  most  likely  to  make  them  buy  the  advertised  product. 
It  is  very  much  like  asking  a  man  what  he  would  do  if  his 
house  burned  up  in  the  night.  The  measurement  of  impres- 
sions in  relative  terms  offers  considerably  less  difficulty,  as 
has  been  demonstrated  in  the  experimental  work  upon  sensa- 
tion, esthetic  judgments,  and  so  on.  Predicting  probable 
conduct  is  a  much  more  hazardous  matter.  It  is  extremely 
improbable  that  we  can  really  tell  what  we  will  do  under  a 
hypothetical  condition  unless  we  have  developed  a  very 
definite  habit  for  meeting  that  situation.  Then  the  chances 
are  that  we  will  have  two  or  more  habits  which  are  about 
equally  serviceable.  Unfortunately  for  the  advertiser,  a  con- 
siderable percentage  of  the  readers  of  advertisements  have 
formed  the  habit  of  appreciating  advertisements  and  seldom 
if  ever  responding. 

The  reading  of  advertisements  has  become  a  fixed  habit 
with  many  persons,  not  because  they  expect  to  buy  anything, 
but  because  the  advertisements  are  an  essential  part  of  the 
enjoyable  features  of  the  magazine.  They  are  looked  at  for 
esthetic  appreciation,  they  are  looked  at  for  news  value,  for 


422  H.  F.  ADAMS 

they  give  information  concerning  the  industrial  activities  of 
the  country  which  could  never  be  found  in  the  body  of  the 
magazine. 

The  general  conclusion  which  we  seem  forced  to  accept  is 
that  the  order  of  merit  test  is  not  a  very  adequate  laboratory 
method  for  testing  the  business  value  of  advertisements. 
Where  it  is  possible  to  obtain  accurate  business  measurements, 
the  laboratory  test,  using  students  as  subjects,  appears  to  be 
quite  inadequate.  Where  it  is  impossible  to  secure  accurate 
business  measurements,  the  laboratory  test  may  be  adequate. 
There  is  no  way  of  telling. 


VOL.  XXII.  No.  6  November,  1915 


THE  PSYCHOLOGICAL  REVIEW 


REACTIONS  TO  THE  CESSATION  OF  STIMULI  AND 
THEIR  NERVOUS  MECHANISM 

BY  HERBERT  WOODROW 

University  of  Minnesota 

The  study  of  reactions  to  the  cessation  of  stimuli,  although 
hitherto  largely  neglected,  nevertheless  presents  a  number  of 
points  of  genuine  scientific  interest.  Reactions  to  the  cessa- 
tion of  stimuli,  or  cessation  reactions,  are  the  same  as  regards 
the  reaction  movement  as  ordinary  reactions  to  the  beginning 
of  stimuli,  or  beginning  reactions.  While,  in  the  case  of 
beginning  reactions,  we  have  energy  acting  upon  some  receptor 
of  the  individual's  nervous  system,  and  producing  a  motor 
response,  in  the  case  of  cessation  reactions,  we  have  merely 
the  discontinuance  of  energy,  which,  on  the  reflex  theory, 
would  readily  account  for  the  discontinuance  of  the  motor 
response.  But  reference  to  more  complex  processes  than 
mere  reflex  conduction  is  necessary  in  order  to  understand 
how  the  mere  discontinuance  of  energy  can  produce  a  positive 
reaction  similar  to  any  produced  by  the  application  of  energy; 
and  yet,  if  cessation  reactions  are  found  to  be  as  quick  as 
beginning  reactions,  the  same  complexity  of  mechanism  must 
be  presumed  for  both. 

Another  point  of  interest,  in  connection  with  cessation 
reactions,  is  the  question  whether  the  relation  of  intensity  of 
stimulus  to  reaction  time  is  the  same  as  in  beginning  reactions, 
where  the  times  are  longer  with  weak  stimuli  than  with  strong. 
This  relation  might  be  reversed  if  the  reason  for  the  long 
reaction  times  with  the  weak  stimuli  was  that  in  such  cases  a 
weak  nervous  current  was  meeting  with  great  resistance  which 
it  took  a  long  time  to  overcome:  for  then  the  cessation  of  the 

423 


424  HERBERT  WOODROW 

weak  nervous  current  could  not  also  meet  with  great  resistance, 
but,  on  the  other  hand,  the  weaker  the  current,  the  more  its 
cessation  would  be  favored. 

That  cessation  reactions  may  throw  some  light  upon  the 
explanation  of  the  differences  in  reaction  time  which  occur 
with  variation  in  the  mode  of  stimulus  has  already  been 
recognized.1  The  fact,  that  with  moderate  intensities,  the 
reaction  time  to  sound  is  ordinarily  shorter  than  that  to  light 
is  commonly  explained  on  the  ground  that  the  stimulation  of 
the  ear  by  sound,  a  mechanical  process,  takes  less  time  than 
the  stimulation  of  the  eye  by  light,  a  chemical  process. 
That  this  explanation  is  as  yet  a  matter  of  speculation  must 
be  admitted,  as  has  been  pointed  out  by  Dunlap  and  Wells, 
who  instigated  a  series  of  experiments  designed  to  aiford  a 
more  satisfactory  explanation.2  Wells,  with  this  same  prob- 
lem in  mind,  conducted  some  experiments  in  which  the  reac- 
tions occurred  upon  the  disappearance  or  occlusion  of  the 
stimulus.  That  is,  the  stimulus  consisted  in  darkness, 
preceded  and  followed  by  illumination,  with  the  subject  re- 
acting at  the  moment  the  darkness  appeared.  From  his 
experiments,  he  concluded  that  the  lag  in  the  sensory  process  in 
the  case  of  vision  cannot  account  for  as  much  as  10  a  of  the 
lengthening  of  the  visual  reaction  time  beyond  that  of  the  audi- 
tory. The  argument,  by  which  he  arrives  at  this  conclusion, 
need  not  here  be  analyzed,  as  it  is  not  based  so  much  upon  the 
reaction  times  to  the  disappearance  of  the  stimulus,  as  upon 
the  fact  that  an  interruption  of  the  light  for  only  10  a  was 
found  to  be  plainly  perceivable.3  As  regards  the  reaction 
time  to  the  disappearance  of  the  light  stimulus,  Wells  con- 
cludes that  it  differs  little  from  that  to  the  appearance  of  the 
light.  This  conclusion  is  supported  by  a  large  number  of 
sensory  reactions,  and  is  in  conformity  with  that  indicated 
by  the  data  presented  below. 

Another  question  concerning  cessation  reactions  is  whether 
the  after-image  has  anything  to  do  with  determining  the 

1  Wells,  G.  R.,  'The  Influence  of  Stimulus  Duration  on  Reaction  Time/  Psychol. 
Monog.,  5,  1913. 

2 'Some  Experiments  with  Reactions  to  Visual  and  Auditory  Stimuli,'  PSYCHOL. 
REV.,  1910,  319. 

3  Op.  «*.,  65. 


•       CESSATION  OF  STIMULI  425 

reaction  time.  Many  other  questions  also  suggest  them- 
selves, but  the  problems  that  have  been  referred  to  are 
sufficient  to  indicate  the  nature  of  the  scientific  interest  of 
the  present  investigation.1 

In  the  case  of  all  the  reactions  here  reported,  the  in- 
structions called  for  a  reaction  which  would  ordinarily  be 
regarded  as  a  form  of  "motor"  reaction.  Reactions  are 
usually  divided  into  two  main  groups,  those  in  which,  during 
the  preparatory  interval,  the  attention  is  mainly  directed  to 
the  stimulus,  called  sensory,  and  those  in  which  it  is  focused 
primarily  upon  the  reaction  movement,  called  motor.  A 
more  important  distinction,  however,  at  least  from  the  point 
of  view  of  reaction  time,  is  that  between  reactions  with  instruc- 
tion to  react  as  quickly  as  possible,  and  reactions  without 
such  instruction.2  In  the  present  instance,  the  subjects  were 
always  instructed  to  make  every  reaction  as  quickly  as  they 
possibly  could.  Nothing  was  said  about  the  direction  of 
attention,  but  the  subjects'  introspections  indicated  that  their 
attention  was,  primarily,  neither  upon  the  stimulus  or  its 
image,  nor  upon  the  reaction  movement  or  its  image,  but 
upon  the  idea  of  reacting  as  quickly  as  possible.  Just  how 
this  idea  was  carried  in  the  subjects'  minds,  that  is,  in  what 
imagery,  or  whether  in  any  imagery,  I  am  unable  to  conclude 
from  the  introspective  data.  No  attempt  was  made  at  elab- 
orate systematic  introspection. 

Apparatus. — The  reaction  times  were  measured  by  means  of  a  Hipp's  chronoscope. 
The  chronoscope  circuit  and  the  stimulus  circuit  were  separate,  but  by  means  of  a 
double  switch  both  circuits  could  be  closed  simultaneously.  The  stimulus,  for  light 
reactions,  consisted  in  the  illumination  of  a  Geissler's  tube,  while  for  sound  reactions, 
the  stimulus  was  the  vibration  of  a  telephone  receiver.  For  beginning  reactions,  both 
the  chronoscope  and  stimulus  circuits  were  closed  at  exactly  the  same  instant  by  means 
of  the  double  switch.  Each  side  of  this  switch  was  provided  with  a  platinum  wire 
which  sank  into  an  adjustable  cup  of  mercury  when  the  experimenter  tapped  upon  the 
switch  handle.  For  cessation  reactions,  the  stimulus  circuit  was  arranged  so  that  it 
was  closed  when  the  handle  of  the  switch  was  raised,  and  broken  when  the  handle 
was  tapped  down.  Thus,  in  this  case,  the  chronoscope  circuit  was  closed  as  the  stimulus 
circuit  was  broken,  though  there  was  an  exceedingly  slight  time  between  the  breaking 
of  the  latter  and  the  closing  of  the  former.  This  time,  when  measured,  was  found  to 

1The  general  subject  of  cessation  reactions  was  first  suggested  to  me  by  Pro- 
fessor H.  C.  Warren  of  Princeton,  in  1907.  The  results  here  reported  on  sound  were 
presented  in  full  in  a  paper  read  in  April,  1912,  before  the  Minnesota  Psychological 
Conference. 

8  See  Woodrow,  'The  Measurement  of  Attention,'  Psychol.  Monog.,  1915,  Chap.  n. 


426  HERBERT  WOODROW 

vary  from  o  to  3  <r,  but  is  regarded  as  a  constant  error  of  2  cr,  and  added  to  all  averages 
of  cessation  reaction  times. 

The  chronoscope  circuit  included  besides  the  chronoscope  and  half  of  the  double 
switch  already  mentioned,  the  subject's  reaction  key,  a  battery  of  Edison  primary  cells 
of  12  volts,  and  a  Wundt's  fall-hammer.  The  chronoscope  was  controlled  before  and 
after  each  50  reactions,  by  means  of  the  fall-hammer,  and  the  fall-hammer  itself  was 
tested  each  day  with  a  250  d.v.  fork. 

The  stimulus  circuit,  when  arranged  for  light  reactions,  included,  as  already 
stated,  a  Geissler's  tube.  This  tube  was  suspended  before  an  oblong  aperture  in  a 
dark  box,  a  few  feet  in  front  of  and  slightly  below  the  subject's  eyes,  as  he  sat  in  the 
dark-room  at  his  reaction  key.  The  Geissler's  tube  was  actuated  by  an  inductorium 
placed  in  the  experimenter's  room.  The  buzzer  of  the  inductorium  was  kept  going 
continuously  during  the  experiment,  but  only  the  secondary  circuit,  which  included 
the  Geissler's  tube,  passed  through  the  operator's  double  switch,  and  so  the  tube  was 
luminous  only  when  the  secondary  circuit  was  closed  at  this  switch.  In  order  to 
weaken  the  intensity  of  the  stimulus,  no  change  was  made  in  the  electrical  circuits,  but 
a  ground  glass  covered  with  white  paper  was  placed  over  the  aperture  of  the  dark  box 
containing  the  Geissler's  tube. 

In  the  case  of  sound  reactions,  the  sound  used  as  a  stimulus  was  that  made  by  a 
telephone  receiver,  through  which  there  passed  a  current  which  was  interrupted  both 
50  and  250  times  per  second,  by  two  electro-magnetic  tuning  forks.  All  the  current 
passed  through  the  forks,  but  the  telephone  was  in  a  shunt  circuit.  Consequently,  the 
-forks  ran  continuously,  whereas  the  telephone  ran  only  while  its  circuit  was  closed  at 
the  experimenter's  double  switch.  By  decreasing  the  resistance  in  parallel  with  the 
telephone,  the  loudness  of  the  telephone  could  be  decreased. 

The  reason  for  running  the  telephone  current  through  both  a  50  and  a  250  fork 
was  that  only  in  this  way  could  the  click  which  followed  the  break  of  the  current  be 
eliminated.  This  method  is  noted  by  Pillsbury  in  his  discussion  of  'Methods  for  the 
Determination  of  the  Intensity  of  Sound,'1  and  is  one  that  I  have  long  employed.2 
Records  of  the  vibration  of  the  telephone  plate  were  obtained  by  attaching  a  light  glass 
pointer  to  the  plate  and  having  this  pointer  mark  upon  a  smoked  drum  alongside  a 
Pfeil  time  marker  placed  in  the  chronoscope  circuit.  A  sample  of  these  records  is 
here  reproduced. 


The  vibrations  of  the  250  fork  are  seen  superimposed  upon  those  of  the  50  fork. 
The  record  shows  that  the  sound  started  in  at  its  maximum  intensity  with  the  first 

1 '  Report  of  the  Committee  of  the  American  Psychological  Association  on  the 
Standardizing  of  the  Procedure  in  Experimental  Tests,'  Psychol.  Monog.,  i,  1910. 
Pillsbury  writes  as  follows:  "Dr.  Shepard,  working  in  my  laboratory,  found  that  the 
click  could  be  lessened  to  a  point  of  not  being  noticed  if  two  tones  were  superimposed 
upon  the  telephone.  He  used  the  commercial  current  of  60  cycles  and  a  250  d.v.  fork. 
The  physical  basis  for  the  effect  is  obscure,  but  the  empirical  effect  is  obvious." 

2  See  'A  Quantitative  Study  of  Rhythm,'  Archives  of  Psychol.,  12,  1909. 


CESSATION  OF  STIMULI  427 

vibration  of  the  telephone  plate,  and  that  it  stopped  as  suddenly  as  it  began.  It  will 
be  noted  that  no  large  vibrations  follow  the  breaking  of  the  circuit  as  they  would  if 
there  were  a  click.  A  number  of  careful  observers  agreed  that  there  was  no  noticeable 
click  at  either  the  closing  or  the  opening  of  the  circuit,  thus  confirming  the  objective 
record. 

Sound  reactions  were  taken  with  three  different  intensities 
of  stimulus,  called  medium,  weak  and  liminal.  Physical 
measurements  of  the  intensity  were  not  made,  but  care  was 
taken  to  keep  the  current  the  same  throughout  the  work 
with  any  one  intensity.  The  reaction  times  themselves  offer 
a  sufficient  index  of  the  intensity.  The  intensity  given  in 
Table  I.  as  liminal,  in  reality  exceeded  the  true  limen  by  an 
extremely  small  amount.  It  was  determined  as  follows:  Four 
series  of  minimal  changes  in  intensity  were  used,  two  of  which 
passed  from  an  audible  to  an  inaudible  sound  and  two  from 
an  inaudible  to  an  audible  one.  This  procedure  was  just 
what  one  might  employ  to  determine  the  sensation  threshold. 
The  sound  was  then  placed  not  at  the  average  liminal  inten- 
sity obtained,  but  at  the  lowest  intensity  which  did  not  fail 
to  produce  a  sensation  in  any  of  the  four  series. 

Since  an  object  of  the  present  study  is  a  comparison  of 
cessation  reactions  with  beginning  reactions,  both  kinds  of 
reactions  were  always  taken  at  each  sitting  of  one  hundred 
reactions.  On  alternate  days  the  middle  fifty  reactions  were 
cessation  reactions  and  the  first  and  last  twenty-five  were 
beginning  reactions;  while  on  the  remaining  days  the  middle 
fifty  were  beginning  reactions  and  the  first  and  last  twenty- 
five  were  cessation  reactions.  In  the  tables  below,  averages 
for  beginning  and  cessation  reactions  given  on  the  same  line 
of  the  table  were  obtained  at  the  same  sitting.  Each  average 
is  the  average  of  fifty  reactions.  No  reactions  were  thrown 
out  on  account  of  their  deviation  from  the  average,  except  in 
the  case  of  the  liminal  sound.  However,  all  reactions  which, 
by  a  prearranged  signal,  the  subject  indicated  were  mistakes, 
as  well  as  all  cases  of  error  of  manipulation  on  the  part  of  the 
experimenter,  were  rejected.  In  the  case  of  the  liminal  sound 
there  were  a  number  of  cases  where  no  reaction  at  all  occurred 
and  some  that  were  very  long,  from  1,500  to  5,000  a.  These 
long  reactions  occurred  both  in  the  case  of  beginning  and 


HERBERT  WOODROW 

cessation  reactions,  but  all  reactions  over  1,500  cr  were  not 
counted.  The  total  number  of  reactions  to  sound  and  light 
stimuli  reported  in  the  following  tables  is  10,000. 

As  a  warning  signal,  in  the  case  of  beginning  reactions  the 
click  of  an  electric  sound-hammer  was  used,  and  given  always 
two  seconds  before  the  reaction  stimulus,  the  interval  being 
indicated  to  the  experimenter  by  means  of  a  pendulum.  In 
the  case  of  cessation  reactions  the  beginning  of  the  stimulus 
itself  acted  as  the  warning  signal.  The  cessation  of  the 
stimulus  always  occurred  two  seconds  after  its  beginning. 

Five  subjects  were  used,  three  of  which,  subjects  Ww,  Ht, 
and  St  were  quite  practiced  in  beginning  reactions  before  the 
work  began,  while  the  other  two,  subjects  Vs  and  Sz,  were 
altogether  unfamiliar  with  work  in  reaction  time. 

The  results  obtained  for  reactions  to  sound  and  to  light 
are  presented  in  Tables  I.,  II.  and  III.  These  tables  show 
the  results  of  each  sitting  in  the  order  in  which  they  were 
obtained.  The  results  are  summarized  in  Table  IV.  In  this 
latter  table,  the  mean  variation  given  is  the  average  mean 
variation  for  a  series  of  fifty  measurements. 

The  conclusion  to  be  drawn  is  clear  and  simple.  In  the 
case  of  sound  and  light  reactions,  there  is  no  appreciable 
difference  between  reaction  time  to  the  beginning  of  a 
stimulus  and  reaction  time  to  its  cessation,  no  matter  what  the 
intensity  of  the  stimulus,  and  no  matter  what  its  mode.  In 
view  of  the  variability  in  reaction  times,  such  a  close  corre- 
spondence between  the  cessation  and  the  beginning  reaction 
times  as  shown  by  Tables  I.  to  IV.  could  not  be  regarded 
as  a  reasonable  expectation  unless  the  true  values  of  both  were 
in  all  cases  substantially  the  same. 

It  is  to  be  regretted  that  results  with  other  senses  than 
light  and  sound  were  not  obtained.  Difficulties  of  technique 
were  largely  responsible  for  limitation  of  the  work  to  these 
modalities.  Some  reactions  to  touch  were  taken,  however, 
using  an  intermittent  current  passing  through  two  fingers  of 
the  left  hand,  each  finger  being  placed  in  a  salt-water  elec- 
trode; but  so  much  difficulty  was  experienced  as  a  result  of 
sensory  adaptation  and  the  after-tingling  of  the  fingers,  that 


N,  for  each  av.  =  50'. 


CESSATION  OF  STIMULI 
TABLE  I 

SOUND  REACTIONS 

Total  No.  of  reactions  =  4,000. 


429 


Intensity 

Subj. 

Series 

Beginning  Reactions 

Cessation  Reactions 

Av. 

M.  V. 

Av. 

M.  V. 

^tedium        .  . 

Ht 

II 

« 
(( 
<« 
M 

« 

Fj 
«c 

<« 
M 
(1 
«« 
(I 
«< 
M 

Sz 
<« 

M 
M 
« 
« 
M 
M 
M 

ffj 

|| 

Pj 

« 

«( 
<( 
M 

•  Sz 

u 
II 
M 

«( 

Ht 
M 

u 

F> 
« 

« 

I. 
II. 
III. 

IV. 
V. 
VI. 
VII. 
VIII. 
Av. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
VIII. 
Av. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
VIII. 
Av. 
I. 
II. 
III. 
IV. 
Av. 
I. 
II. 
III. 
IV. 
Av. 
I. 
II. 
III. 
IV. 
Av. 
I. 
II. 
Av. 
I. 
II. 
Av. 

US 
H3 
121 
I36 
123 

116 
106 

122 
119 
143 
123 
141 

135 
140 

145 
132 
137 
137 
I46 

143 

162 

137 
140 

154 

147 
IS7 
I48 
172 
202 

175 
I85 
I84 

1  88 
196 
160 
150 
174 
215 
198 

222 
2O  I 
209 

829 
728 

779 

755 
995 
875 

II 

19 
20 
20 
13 
14 
12 

15 

16 

3 

18 
i5 

20 
12 
15 
I? 

17 

20 

17 

20 

23 
14 
22 
26 
14 
19 

34 

% 

24 
26 

18 

28 

II 

20 

31 

34 

? 

33 

146 
114 
130 
137 
315 
226 

121 

125 
128 
127 

"5 

121 

H3 
1  2O 
121 

144 
142 

155 
147 
136 
144 

138 
140 

143 

157 
155 
143 
151 

I5J 
136 

147 
144 
148 
170 
190 
170 
201 
I83 

186 
X55 
155 
171 
167 
226 
204 
223 
218 
218 

682 

807 

745 
735 
909 
822 

15 
15 
17 
15 
15 
II 

15 
13 
IS 
16 

20 

18 

21 
14 

% 

14 

17 
24 

12 
22 

18 
23 
17 
25 
25 

21 

44 
26 

27 
36 
33 

20 

32 

20 

^7 
22 

35 
27 
40 

29 
33 
no 

147 
133 
177 

359 
268 

« 

« 

« 

u 

« 

a 

« 

« 

« 

«c 

M 

<( 

«c 

« 
« 

<« 

«c 
M 

«( 

M 

«( 

M 

M 

« 

M 

Weak.. 

< 

i 

c 

( 

« 

« 

I 

e 

t 

( 

i 

< 

1 

< 

Liminal  

«< 

M 

M 

in 

M 

43° 


HERBERT  WOODROW 


N,  for  each  av.  =  50. 


TABLE  II 

REACTIONS  TO  BRIGHT  LIGHT 

Total  No.  of  reactions  =  3, 600. 


Beginning 

Reactions 

Cessation 

Reactions 

Subj. 

Series 

Av. 

M.  V. 

Av. 

M.  V. 

Ww 

I. 

1  60 

je 

IC2 

17 

K 

II. 

14.2 

U 

14.7 

16 

« 

III. 

IC4. 

J? 

y 

160 

16 

(i 

IV. 

I4.O 

17 

TC2 

21 

<( 

v 

A7 
1  60 

IO 

TP-7 

ry 

it 

VI. 

1  68 

24. 

JAA 

AJ 
/? 

« 

VII. 

JCQ 

17 

IAC 

i6 

(i 

VIII. 

1  4.O 

If 

157 

Id 

« 

Av. 

154 

16 

I"?I 

16 

Ht    

I. 

156 

18 

1  60 

18 

u 

II. 

163 

2S 

JCg 

2f 

u 

III. 

1  68 

IO 

171 

12 

« 

IV. 

160 

21 

171 

jr 

(( 

Av 

162 

21 

l67 

18 

St  .  . 

I. 

IQO 

17 

187 

2O 

(( 

II. 

IQ2 

22 

IQO 

J7 

«« 

III. 

187 

JC 

1  80 

2O 

«( 

IV. 

178 

21 

IQ2 
~" 

16 

« 

V. 

187 

22 

176 

26 

<( 

VI. 

178 

10 

187 

16 

(( 

VII. 

176 

II 

I  7O 

22 

II 

VIII. 

178 

28 

101 

1$ 

(1 

Av. 

X83 

21 

184 

19 

Vs.  . 

I. 

2OO 

24 

196 

21 

(i 

II. 

2O7 

22 

177 

12 

<( 

III. 

IQO 

18 

1  80 

11 

« 

IV. 

IQ3 

14. 

IQ3 

18 

« 

V. 

1  04 

17 

IQ2 

IQ 

u 

VI. 

170 

20 

178 

16 

« 

VII. 

1  86 

18 

1  80 

16 

« 

VIII. 

1  86 

21 

184 

20 

«( 

Av. 

192 

19 

185 

i? 

Sz.. 

I. 

196 

IJ 

200 

23 

(f 

II. 

200 

23 

193 

27 

tl 

III. 

207 

21 

193 

18 

u 

IV. 

177 

23 

2O  I 

14 

« 

V. 

IQI 

2$ 

2OO 

22 

u 

VI. 

IQO 

21 

2OO 

23 

te 

VII. 

*y? 

216 

28 

2O  C 

21 

« 

VIII. 

221 

24. 

212 

26 

(C 

Av. 

2OI 

22 

201 

22 

the  results  cannot  be  regarded  as  reliable.  The  few  that 
were  obtained  showed  a  marked  prolongation  in  reaction 
time  with  decrease  in  the  intensity  of  the  stimulus,  both  with 
beginning  and  cessation  reactions.  The  cessation  reactions, 
however,  were  uniformly  about  30  <r  longer  than  the  beginning 
reactions,  which  fact  may  be  attributed  to  the  after-tingling 


CESSATION  OF  STIMULI 


431 


of  the  fingers  set  up  by  the  irritation  of  the  electric  current. 
Some  experiments  were  also  tried,  in  which  the  stimulus 
consisted  in  the  fall  and  rise  of  an  electric  hammer  arranged 
to  strike  the  back  of  the  finger.  In  this  case,  while  the 
stimulus  was  adequate,  one  could  not  be  certain  that  the 


N,  for  each  av.  =  50. 


TABLE  III 

REACTIONS  TO  WEAK  LIGHT 

Total  No.  of  reactions  =  2,400. 


Subj. 

Series 

Beginning  Reactions 

Cessation  Reactions 

Av. 

M.V. 

Av. 

M  .  V. 

Ht.  . 

I. 
II. 
III. 

IV. 
V. 
VI. 
VII. 
VIII. 
Av. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
VIII. 
Av. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
VIII. 
Av. 

179 
I96 
211 

216 

204 
221 
211 
201 

205 

221 
217 
252 
240 
244 

*P 

269 

241 
243 

254 

239 
269 
296 
284 
258 
264 
280 
268 

35 
44 
37 
34 

20 

% 

33 
33 
25 
23 

% 

22 
29 

19 
28 
26 
2? 

33 
30 

22 

% 

24 
27 
28 

192 
I78 
205 
2I4 
194 
217 
217 
209 
203 

230 

222 
214 
234 
255 
229 
24I 
243 
234 
244 
250 

% 

268 

255 
228 
230 
250 

28 
30 
26 
22 

18 
24 

ii 

24 

21 

15 
21 

30 
21 

18 

22 

17 
21 

15 
22 

31 
29 

30 

34 

21 

23 
26 

tt 

« 

ii 

tt 

tt 

tt 

tt 

tt 

Vs 

tt 

tt 

tt 

tt 

tt 

tt 

tt 

n 
St.. 

ti 

it 

tt 

tt 

tt 

tt 

tt 

tt 

removal  of  the  pressure  was  a  change  equivalent  in  intensity 
to  its  occurrence;  but  the  results  obtained  in  this  case  were  to 
the  effect  that  the  beginning  and  cessation  reaction  times  are 
equal.  Thus,  with  one  subject,  the  average  reaction  time 
for  100  reactions  to  the  beginning  of  the  stimulus,  was  119  cr 
and  for  100  reactions  to  its  removal,  1200-.  With  another 
subject,  the  average  for  100  beginning  reactions  was  128  <r 
and  for  100  cessation  reactions  with  the  same  stimulus, 
132  <r. 


432 


HERBERT  WOODROW 


The  simplicity  of  the  conclusions  drawn  above  from  the 
results  presented  in  Tables  I.  to  IV.  should  not  blind  us  to 
the  important  bearing  that  they  have  on  current  theories  of 
the  action  of  the  nervous  system.  The  explanation  of  the 
results  here  presented,  by  means  of  the  theories  of  nervous 
action  that  are  at  present  most  in  vogue,  is  extremely  dif- 
ficult,— so  difficult,  in  fact,  as  to  suggest  that  these  theories 
are  themselves  incorrect,  and  that  they  must  either  be  given 

TABLE  IV 

A  SUMMARY  OF  TABLES  I.,  II.  AND  III 


Beginning 

Reactions 

Cessation 

Reactions 

Mode 

Intensity 

Subj. 

Av. 

Av.  M.  V. 

Av. 

Av.  M.  V. 

Sound   

Medium.  . 

Ht 

110 

16 

121 

JC 

« 

Vs 

137 

17 

14.  -j 

17 

(1 

Sz 

*j/ 
14.8 

IQ 

H8 

21 

w$ 

Weak 

Ht 

184. 

26 

183 

yy 

« 

Vs 

174. 

2O 

** 

167 

22 

«c 

Sz 

2OQ 

31 

218 

?? 

Liminal  

Ht 

770 

I1O 

74.  c 

/?? 

ii 

Vs 

87? 

* 
226 

822 

168 

Light 

Brieht   . 

Ww 

ISA 

16 

ici 

16 

8 

f" 

Ht 

*5t 
l62 

21 

167 

18 

« 

« 

St 

i8<? 

21 

184. 

IQ 

H 

M 

Vs 

IQ2 

IQ 

185 

17 

«< 

« 

Sz 

2O  I 

22 

2O  I 

22 

« 

Weak.  . 

Ht 

2O  C 

?? 

203 

24. 

II 

<( 

Vs 

24,  3 

26 

234. 

21 

«C 

M 

Sz 

268 

28 

250 

26 

up  or  seriously  modified.  In  particular,  it  can  be  shown  that 
certain  phenomena  which  it  is  customary  to  explain  by  ref- 
erence to  the  latent  period  of  sensory  stimulation  or  by  ref- 
erence to  certain  hypothetical  effects  of  the  synapse,  are  not 
adequately  explained  thereby.  Their  explanation  requires 
either  a  theory  which  is  incompatible  with  the  statement  that 
the  reflex  is  the  type  of  all  nervous  activity,  or  else  a  theory 
which  involves  some  modification  of  the  ordinary  concept 
of  the  reflex. 

In  the  first  place,  let  us  consider  the  explanation  of  the 
increase  in  reaction  time  with  decrease  in  the  intensity  of 


CESSATION  OF  STIMULI  433 

stimulus.  Pieron,1  in  a  recent  able  discussion  of  this  matter, 
concludes  that  the  main  factor,  in  determining  the  increase 
in  reaction  time,  is  the  increase  in  the  latent  period  of  ex- 
citation of  the  first  sensory  neurone  with  decrease  in  intensity 
of  stimulation.  His  discussion  of  other  possible  explanatory 
factors,  however,  is  unprejudiced.  He  correctly  regards  as 
very  doubtful  the  proposition  that  the  rate  of  transmission 
of  nervous  energy  along  a  neurone  varies  with  the  intensity  of 
stimulation.2  Likewise,  and  with  equal  correctness,  he  rejects 
the  idea  that  the  effect  can  be  explained  by  reference  to  phe- 
nomena on  the  motor  or  centrifugal  side  of  the  process.3  He 
does  not  deny,  though,  that  when  the  excitation  is  weakened 
there  may  be  an  increase  in  the  time  of  transmission  from 
one  neurone  to  another.  He  thinks,  however,  that  the  vari- 
ations in  time,  due  to  this  last-mentioned  factor,  are  not  very 
considerable,  and  that  they  do  not  suffice  to  explain  the 
variations  obtained  experimentally.  Pieron  also  raises  the 
question  whether  the  central  or  brain  phase  is  not  the  seat 
of  the  principal  variations.  "La  partie  la  plus  longue,  dans 
cette  phase,  correspond  a  la  circulation  de  1'influx  associatif 
dirige,  et  sa  brievete  depend  surtout  de  Petat  d'attention, 
c'est-a-dire  de  Paiguillage  prealable  qui  assure  la  conduction 
de  cet  influx  par  les  voies  les  plus  rapides."4  He  argues, 
however,  that  since  the  reactions  are  always  accompanied 
by  a  state  of  intense  attention,  the  fact  that  a  more  intense 

1  'Recherches  sur  les  lois  de  variation  des  temps  de  latence  sensorielle  enfonction 
des  intensites  excitatrices,'  Ann'ee  psycho!.,  1914,  17-96. 

1  In  confirmation,  see  the  following:  Gotch,  Journ.  of  PhysioL,  1902,  395.  Koike, 
Ztsch.  f.  Biol.,  1910,  310.  Lucas,  Journ.  of  Physiol.,  1911,  46.  Adrian,  Ibid.,  1912, 
389;  1913,  384- 

*  In  this  connection,  one  may  well  cite  the  work  of  Moore,  'A  Study  of  Reaction 
Time  and  Movement,'  Psychol.  Monog.  Sup.,  i,  1904.    Moore  writes,  "In  one  and 
the  same  series  the  reaction  time  undergoes  considerable  change,  but  the  movement  time 
is  fairly  constant.     If  you  introduce  factors  which  increase  the  difficulty  of  attention, 
the  reaction  time  is  lengthened  and  rendered  still  more  variable,  but  the  time  of  move- 
ment remains  about  the  same,"  p.  58.     "That  the  efficient  path  from  cortex  to  muscle 
is  not  affected  by  the  disturbance  of  the  attention  and  that  reaction  time  is  not 
lengthened  by  any  changed  conditions  along  the  path,  seem  to  be  conclusions  warranted 
by  the  fact  of  constancy  in  the  time  of  the  movement  by  which  the  reaction  was  exe- 
cuted," p.  59. 

*  Op.  cit.,  73-74. 


434  HERBERT  WOODROW 

excitation  better  calls  out  attention  cannot  be  of  very  great 
importance.  Concerning  his  final  hypothesis,  that  the  ex- 
planation of  the  relation  between  reaction  time  and  intensity 
of  stimulus  lies  chiefly  in  the  latent  period  of  the  sense-organ, 
Pieron  himself  admits  that  it  is  an  hypothesis,  the  truth  of 
which  he  cannot  demonstrate.  One  of  the  principal  argu- 
ments which  he  suggests  in  favor  of  his  conception  is  the 
fact  that  the  data  at  hand  indicate  that  the  relation  between 
intensity  of  stimulus  and  reaction  time  differs  in  the  case  of 
different  senses. 

In  spite  of  the  lack  of  evidence  in  support  of  the  con- 
clusions of  Pieron  concerning  the  role  of  the  sensory  latent 
period,  they  have  a  certain  plausibility  which  would  no 
doubt  lead  many  to  agree  with  him.  Others,  however,  like 
Sherrington,  would  give  more  stress  to  the  role  of  the  synapse. 
Sherrington  calls  attention  to  the  fact  that  the  latent  period 
of  reflexes,  that  is,  the  time  between  application  of  stimulus 
and  appearance  of  end-effect,  increases  with  decrease  in  the 
intensity  of  the  stimulus.1  Thus,  he  finds  that  the  latent  time 
of  the  scratch-reflex  varies  from  140  a  with  intense  stimula- 
tion to  500  (7,  or  even  several  thousand  cr,  with  weak  stimu- 
lation. He  writes:  "This  slackening  of  propagation  speed 
under  weak  stimuli  is,  I  would  urge,  a  more  significant  differ- 
ence between  reflex-conduction  and  nerve-trunk  conduction 
than  is  the  mere  greater  slowness  of  the  former  than  the 
latter."2  This  difference  between  conduction  in  reflex-arcs 
and  nerve-trunks  is  referable  to  that  part  of  the  arc  which 
lies  in  the  gray  matter.  The  slower  conduction  in  the  gray 
matter  as  well  as  the  increase  in  reflex  time  with  weak  inten- 
sity of  stimulus  is  supposed  to  be  due  to  phenomena  of 
transmission  occuring  at  the  synapse,  where  a  surface  of 
separation  acts  as  a  resistance  or  barrier  to  the  passage  of  the 
nervous  current  from  one  neurone  to  the  next. 

The  weaker  stimulus,  then,  is  to  be  thought  of  as  resulting 
in  a  longer  reflex  time  because  it  is  delayed  longer  in  trans- 
mission from  one  neurone  to  the  next,  than  is  the  more  intense 

1  'The  Integra tive  Action  of  the  Nervous  System/  1906,  21. 

2  Loc.  cit. 


CESSATION  OF  STIMULI  435 

stimulus.  Sherrington,  apparently,  does  not  regard  the 
effect  of  intensity  on  reflex  time  as  due  in  any  appreciable 
degree  to  the  latent  period  of  the  sense-organ. 

Now,  while  the  prolongation  in  reflex  time  with  decrease 
in  the  intensity  of  the  stimulus  is  a  different  phenomenon 
than  the  prolongation  in  human  reaction  time  with  decrease 
in  intensity,  yet  it  seems  highly  probable  that  the  essentials 
of  the  explanation  are  the  same  in  both  cases.  At  any  rate, 
there  is  just  as  much  evidence  that  the  effect  of  intensity 
upon  reaction  time  is  to  be  explained  by  reference  to  the 
impeding  action  of  the  synapse,  as  that  the  effect  of  intensity 
upon  reflex  time  is  to  be  so  explained.  Fully  as  many  synapses 
are  involved  in  the  voluntary  reactions  of  human  beings  as  in 
the  reflexes  of  the  dog,  and  any  effect  which  results  from  the 
nature  of  the  synapse  must  be  present  in  both  cases  and  must 
be  explained  in  both  cases  by  the  action  of  the  synapse. 

The  inadequacy  of  both  the  sensory  latent  period  and  the 
synapse  theories  may  be  shown,  to  a  large  extent,  by  the  same 
argument:  for  after  all,  both  theories  offer  much  the  same 
explanation  of  the  prolongation  in  reaction  time  with  decrease 
in  intensity  of  stimulus.  In  both  cases,  the  concept  of  re- 
sistance to  be  overcome  is  the  fundamental  one;  in  one  theory, 
the  resistance  is  thought  of  as  occurring  at  the  first  sensory 
neurone  met  with  by  the  stimulus  and  in  the  other,  as  occur- 
ring at  every  synapse.  It  is  the  same  concept  that  is  constantly 
used  in  attempts  at  explaining  the  physiological  side  of  all 
manner  of  psychological  phenomena.1  The  excitation  prc^ 
duced  by  the  stimulus  has  to  exceed  some  minimal  limit,  or 
threshold,  before  it  is  sufficient  to  bring  about  a  reaction.  A 
small  force  has  to  act  longer  to  produce  a  given  effect  than  a 
large  force :  consequently,  it  is  argued,  the  weaker  the  stimulus, 
the  longer  the  time  to  produce  the  required  degree  of  excita- 
tion. 

Now  is  such  an  explanation  as  the  above  tenable?     We 

1  Ladd  and  Woodworth  write  as  follows :  "  In  fine,  it  seems  possible  to  conceive 
the  action  of  the  nerve-centers  as  a  process  of  the  transmission  of  nerve-impulses  that 
is  subject  to  the  peculiarities  of  central  conduction.  Most  of  these  peculiarities  can 
be  stated  in  terms  of  resistance — resistance  in  general  high,  but  variable  with  many 
conditions."  'Elements  of  Physiological  Psychology,'  1911,  287. 


436  HERBERT  WOOD  ROW 

must  conclude  that  it  is  not,  if  for  no  other  reason  than  that 
it  does  not  hold  for  cessation  reactions;  for,  if  we  argue  that 
a  large  resistance  increases  the  time  required  for  any  stimulus 
to  produce  its  effect,  we  cannot  also  argue  that  this  same  large 
resistance  also  increases  the  time  required  for  the  disappear- 
ance or  the  cessation  of  the  effect.  On  the  contrary,  the  dis- 
appearance of  the  effect  should  be  hastened.  A  few  analogies 
will  make  this  clear.  If  we  make  a  slight  impression  on  the 
skin,  it  will  disappear,  or  fall  below  a  prescribed  threshold, 
quicker  than  if  it  is  deep.  The  after-image  of  a  bright  light 
lasts  longer  than  that  of  a  faint  light.  A  string  vibrating 
with  large  amplitude  requires  a  longer  time  to  come  to  rest, 
or  to  fall  below  any  given  threshold,  than  one  vibrating  with 
small  amplitude.  The  plasma  membrane  of  a  nerve  cell 
would  recover  from  a  slight  increase  in  permeability  more 
quickly  than  from  a  great  increase  in  permeability.1  Such 
illustrations,  which  could  be  multiplied  indefinitely,  all  show 
how  improbable  it  is  that  any  resistance  offered  by  the  first 
sensory  neurone,  or  even  by  the  synapse,  would  act  in  such 
a  way  that  it  would  not  only  impede  the  action  of  a  weak 
stimulus  more  than  that  of  a  strong,  but  would  also  impede 
the  cessation  of  the  action  of  the  weak  more  than  that  of  the 
strong. 

One  might  object,  and  not  without  some  justification,  that 
this  argument  leaves  out  of  consideration  the  fact  that  the 
resistance  offered  by  the  synapse  may  not  be  resistance  to 
the  rise  or  fall  of  the  excitation  but  merely  to  its  conduction. 
This  resistance,  it  might  be  alleged,  merely  results  in  the  weak 
current  traveling  along  the  nerve  fibre  more  slowly  than  the 
strong.  In  all  cases,  the  awareness  of  the  cessation  of  the 
stimulus  would  be  delayed  by  the  time  required  for  the 
very  rearmost  part  of  the  stream  of  excitations  produced  by 
the  stimulus  to  pass  from  the  sense-organ  to  the  cortex.  Now, 

1  For  an  excellent  discussion  of  the  electric  phenomena  in  nerve  and  muscle  cells, 
see  Hober,  'Physikalische  Chemie  der  Zelle  und  der  Gewobe,'  4th  ed.,  1914,  especially 
Chap.  XIL,  'Elektrische  Vorgange  an  physiologischen  Membranen.'  Cf.  also  Lillie, 
'The  Relation  of  Stimulation  and  Conduction  in  Irritable  Tissues  to  Changes  in  Per- 
meability of  the  Limiting  Membranes,'  Amer.  J.  of  PhysioL,  Vol.  XXVIII. ,  1911,  197- 
222. 


CESSATION  OF  STIMULI  437 

one  might  argue  that  this  time  would  be  greater  for  weak  than 
for  strong  nervous  excitations.  Against  this  view,  however,  we 
have  the  results  of  recent  physiological  investigations,  which 
show  that  the  rate  of  transmission  of  nervous  impulses  is 
independent  of  their  magnitude.1  More  decisive  is  the  fact, 
apparently  well  established,2  that  the  'all-or-none'  law  applies 
to  the  normal  nerve-fiber.  This  law  is  to  the  effect  that  any 
stimulus  which  excites  a  nerve-fiber  at  all  will  produce  a 
maximal  excitation.  It  follows  that  differences  in  intensity 
of  excitation  of  sensory  nerves  is  due  to  difference  in  the 
number  of  nerve-fibers  (or  conducting  elements)  stimulated, 
or  else,  as  indicated  by  the  results  of  Frohlich,3  to  variation 
in  the  frequency  of  secondary  excitation  waves.  Now,  if 
the  '  all-or-none '  law  be  true,  it  is  impossible  for  any  number 
of  synapses  to  delay  the  excitation  produced  by  a  weak  stim- 
ulus more  than  that  produced  by  a  strong  one.  Consequently, 
the  assumption  of  resistance  offered  by  the  synapse  cannot 
account  for  the  marked  prolongation  in  either  reaction  time  or 
reflex  time  with  decrease  in  intensity  of  stimulus. 

It  is  true  that  fatigued  nerve-fibers  do  not  follow  the  '  all- 
or-none'  law.  It  might  be  held  that,  in  a  similar  way,  a 
sensory  nerve-fiber  subjected  to  stimuli  such  as  light  or  sound 
would  not  follow  this  law.  The  high  frequency  of  the 
secondary  oscillations,  in  the  case  of  the  excitations  produced 
in  an  optic  nerve  by  a  light  stimulus,  might  result  in  the 
nerve  taking  on  the  properties  of  what  Verworn  calls  an 
'heterbolic'  system,4  and  consequently  in  its  showing  variation 
in  magnitude  of  excitation  with  variation  in  intensity  of 
stimulus.  However  this  may  be,  it  is  very  improbable  that 
such  differences  in  intensity  of  excitation  of  single  nerve- 
fibers  (assuming  them  to  exist)  could  account  for  the  increase 

1  In  confirmation,  see  the  following:  Gotch,  Journ.  of  Physiol.,  1902,  395.     Koike, 
Ztsck.  f.  Biol.,  1910,  310.     Lucas,  Journ.  of  Physiol.,  1911,  46.    Adrian,  Ibid.,  1912, 
389;  1913,  384. 

2  Gotch,  Journ.  of  Physiol.,  1902,  392.     Symes  and  Veley,  Proc.  Roy.  Soc.,  B. 
kxxiii.,  1910,  431.     Verworn,  Ztsch.  f.  allgm.  Physiol.,  1912,  277.     Veszi,  Ztsch.  f. 
allgm.  Physiol.,  1912,  321.     Adrian,  Journ.  of  Physiol.,  1913,  389.     Lodholtz,  Ztsch.  f. 
allgm.  Physiol.,  1913,  269.     Lillie,  Amer.  Journ.  of  Physiol.,  Vol.  XXXIV.,  1914,  410. 

8  Ztsch.  f.  Sinnesphysiol,  Vol.  XLVIIL,  1914,  28-165. 
4  Ztsch.  f.  allgm.  Physiol.,  1912,  289. 


438  HERBERT  WOODROW 

in  time  of  cessation  reactions  with  decrease  in  intensity  of 
stimulus.  This  becomes  very  evident  from  a  consideration 
of  reactions  to  a  decrease  in  intensity,  of  which,  after  all, 
cessation  reactions  are  merely  a  limiting  case. 

The  assumption  of  greater  slowness  of  conduction  of  weak 
excitations  than  of  strong,  even  were  it  warranted,  would 
not  account  for  the  fact1  that  a  slight  decrease  in  intensity  of 
a  strong  stimulus  results  in  a  longer  reaction  time  than  a 
larger  decrease  in  the  same  stimulus:  for  it  cannot  be  held  that 
a  slight  decrease  in  excitation  is  conducted  more  slowly  than 
a  large  decrease.  The  decrease  itself  is  not  conducted  at  all, 
but  merely  the  excitation  as  it  exists  before  and  after  decrease. 
It  may  be  urged  that  this  argument  is  not  pertinent,  but  I 
think  there  is  little  doubt  that  just  as  the  reaction  time  to  the 
beginning  of  a  stimulus  equals  that  to  its  cessation,  so  does  the 
reaction  time  to  an  increase  in  intensity  equal  that  to  a  de- 
crease of  the  same  size.  We  know,  at  least,  that  the  reaction 
time,  whether  the  reaction  is  to  an  increase  or  a  decrease  in 
intensity,  is  lengthened  as  the  size  of  the  change  in  intensity 
is  decreased.  Reactions  to  a  decrease  in  intensity  should,  then, 
be  considered  along  with  cessation  reactions. 

Another  point  to  be  considered,  in  addition  to  the  effect 
of  intensity  of  stimulus  upon  reaction  time,  is  the  difference 
in  reaction  time  between  sound  and  light.  Reactions  to  a 
moderately  bright  light  are  longer  than  those  to  a  moderately 
loud  sound.  This  fact  is  not  uncommonly  explained  by  as- 
suming that  the  latent  period  of  stimulation  of  the  sense- 
organ  is  longer  in  the  case  of  light.2  Against  this  assump- 
tion, we  may  urge  the  following  considerations: 

First,  since  cessation  reaction  times  are  the  same  as  be- 
ginning reaction  times  in  both  sound  and  light,  we  would 
have  to  assume  that  in  both  cases  the  latent  period  for  the 

1  See  Woodrow,  'The  Measurement  of  Attention,'  Psychol.  Monog.,  1915,  Chap. 
IV. 

2  Ladd  and  Woodworth  write  as  follows :  " .  .  .  there  seems  good  reason  to  suppose 
that  the  reaction  time  of  sight  is  necessarily  longer  than  that  of  hearing  or  touch,  on 
account  of  the  photochemical  nature  of  its  more  immediate  stimulus."     "On  the 
whole,  the  suggestion  which  probably  is  most  generally  entertained  ...  is  that  already 
adopted  by  us, — namely,  that  the  inertia  or  latent  time  of  different  sense-organs  differs." 
'Elements  of  Physiological  Psychology,'  1911,  472. 


CESSATION  OF  STIMULI  439 

dying  out  of  the  excitation  just  equalled  that  for  its  rise,  that 
is,  not  only  assume  that  the  photochemical  process  was  longer 
in  getting  started  but  also  equally  longer  in  dying  down. 
Second,  if  we  assumed  any  considerable  latent  period  of  stim- 
ulation, it  would  seem  reasonable  to  suppose  that  such  latent 
period  would  increase  markedly  with  weakened  intensity. 
But  as  has  been  pointed  out  in  preceding  sections,  such  an 
increase  in  latent  period  is  incompatible  with  the  fact  that 
reactions  to  the  cessation  of  a  very  weak  stimulus  are  longer 
than  to  the  cessation  of  a  strong  one.  At  any  rate,  the  effect 
of  intensity,  which  cannot  be  explained  by  reference  to  the 
latent  period,  is  sufficient  to  completely  overwhelm  the  effect 
of  the  latent  period,  since  a  very  weak  sound  may  give 
much  longer  reaction  times  than  a  very  bright  light.  Third, 
in  the  case  of  reflexes,  we  know  that  different  reflexes  may  vary 
greatly  in  time  even  when  they  are  elicited  by  direct  stimula- 
tion of  the  sensory  nerve,  so  that  the  latent  period  of  stimula- 
tion of  the  sense-organ  is  not  involved.  Similarly,  a  great 
variation  in  the  time  of  different  reflexes  occurs  where  the 
sense-organ  stimulated  remains  the  same.  For  example, 
the  latent  time  of  the  scratch-reflex  is,  on  the  average,  very 
much  longer  than  that  of  the  flexion-reflex  of  the  same  limb, 
although  the  distance  of  nerve  fiber  conduction  is  not  greater.1 
Fourth,  and  lastly,  it  can  be  shown,  as  will  be  pointed  out 
below,  that  the  degree  of  attention  is  less  with  light  reactions 
than  with  sound,  and  that  this  fact  offers  an  intelligible 
explanation  of  the  variation  in  reaction  time  with  mode  of 
stimulus.  It  is  true  that  reflexes  as  a  rule  do  not  involve 
attention,  but  since  the  work  of  Sherrington,  showing  the 
important  role  of  the  central  nervous  system  in  determining 
the  characteristics  of  reflexes,  it  may  very  well  be  assumed  that 
a  nervous  mechanism  analogous  to  the  nervous  mechanism  of 
attention,  though  less  complex  and  without  conscious  ac- 
companiments, is  involved  in  every  reflex.2 

One  other  point  may  be  mentioned  as  one  which  should  be 

1  Sherrington,   op.  cit.,  p.  21. 

2  "The  interference  of  unlike  reflexes  and  the  alliance  of  like  reflexes  in  their  action 
upon  their  common  paths  seems  to  lie  at  the  very  root  of  the  great  psychical  process  of 
'  attention.' "     Sherrington,  op.  cit.,  234. 


44°  HERBERT  WOODROW 

illuminated  by  knowledge  of  cessation  reactions.  I  refer  to 
the  long  time  required  by  a  weak  intensity  of  stimulus  to 
produce  its  maximal  intensity  of  sensation.  The  data  here 
presented  do  not  deal  exactly  with  this  point,  but  the  experi- 
ment with  the  liminal  sound  as  stimulus  is  of  interest  in  this 
connection.  It  is  known  that  a  sound  of  constant  physical 
intensity  increases  in  apparent  intensity  up  to  a  duration, 
in  the  case  of  weak  sounds,  of  1.5  sees.1  It  ought,  then, 
to  be  possible,  by  using  a  sound  so  weak  as  to  be  in- 
audible until  .  nearly  its  maximum  effect  is  produced,  to 
obtain  a  sound  so  weak  that  it  could  not  be  heard  at  all  for 
a  large  fraction  of  a  second.  The  reaction  time  I  actually 
obtained  for  such  a  sound  was  about  three  fourths  of  a  second,2 
and  the  reaction  time  to  its  cessation  was  fully  as  long.  In  the 
case  of  a  liminal  sound  such  as  here  used,  there  can  be  no 
doubt  that  the  reaction  does  not  occur  until  the  subject  is 
aware,  in  the  case  of  beginning  reactions,  of  the  presence  of 
the  sound,  and  in  the  case  of  cessation  reactions,  of  its  absence. 
It  is  well  known,  apart  from  the  present  data,  that  it  takes 
longer  to  become  aware  of  a  weak  stimulus  than  of  a  strong.3 
It  may  be  said,  then,  that  the  very  long  reaction  time  in  the 
case  of  beginning  reactions  shows  how  very  long  it  takes  to 
become  aware  of  a  liminal  stimulus.  Moreover,  in  view  of  the 
approximate  equality  of  the  beginning  and  cessation  reaction 
times,  it  may  be  concluded  that  just  as  it  takes  longer  to 
become  aware  of  a  weak  stimulus  than  of  a  strong,  so  does  it 
take  longer,  and  about  equally  longer,  to  become  aware  of  the 
cessation  of  a  weak  stimulus  than  of  a  strong. 

Here  again,  we  may  raise  the  question  of  explanation  by 
resistance.  And  there  can  be  little  doubt  that  the  explanation 
of  the  period  required  for  the  rise  of  the  excitation  up  to  the 
awareness  threshold  is  closely  connected,  if  not  essentially 

1  Kafka,  'Ueber  das  Ansteigen  der  Tonerregung/  Psychol.  Stud.,  1907,  256-292. 
See  also  Sander,  'Das  Ansteigen  der  Schallerregung  bei  Tonen  verschiedener  Hohe,' 
Psychol.  Stud.,  1910,  1-38. 

2  The  great  discrepancy  between  this  value  and  the  corresponding  values  obtained 
by  Wundt  (337  o-)  and  by  Pieron  (361  a)  is  probably  due  to  the  stricter  insistence  upon 
liminal  intensity  of  stimulus  in  the  present  instance. 

8  See  Minneman,  'Untersuchungen  uber  die  Differenz  der  Wahrnehmungsgeschwin- 
digkeit  von  Licht  und  Schallreizen,'  Psychol.  Stud.,  1911,  1-82. 


CESSATION  OF  STIMULI  441 

identical,  with  the  explanation  of  the  period  required  for  the 
further  rise  to  a  maximum.  In  the  explanation  by  resistance, 
in  the  present  instance,  the  resistance  would  probably  be 
thought  of  as  at  the  synapse;  but  no  mode  of  behavior  on  the 
part  of  the  synapse  has  yet  been  suggested  which  would 
explain  how  it  can  offer  resistance  both  to  the  rise  and  to  the 
fall  of  the  excitatory  process.  The  cessation  of  the  excitation 
is  not  a  new  excitation  as  we  know  from  the  introspection  that 
the  sound  sensation  merely  ceases, — no  new  sensation  is  set 
up,  when  the  stimulus  is  cut  off.  So  it  is  evident  that  neither 
the  long  period  required  for  the  rise  of  the  excitation  up  to  the 
sensation  or  awareness  threshold,  nor,  in  all  probability,  the 
further  rise  to  a  maximum,  can  be  explained  by  reference  to 
the  concept  of  a  surface  of  separation  at  the  synapse  or  to 
any  other  form  of  resistance  to  conduction  along  nervous  arcs. 

A  consideration  of  the  facts  of  cessation  reactions,  then, 
leads  to  certain  negative  conclusions  concerning  the  explana- 
tory value  of  the  concept  of  resistance,  whether  this  resistance 
is  placed  at  the  point  of  stimulation,  at  the  synapse,  or  in  the 
whole  neurone.  Such  resistance  cannot  explain  the  fact 
that  cessation  reactions  to  a  weak  stimulus  are  longer  than 
to  a  strong  one,  but  on  the  other  hand  would  tend  to  cause  us 
to  expect  the  reverse.  Moreover,  since  both  cessation  and 
beginning  reactions  follow  the  same  law  as  regards  variation 
in  time  with  variation  in  intensity  of  stimulus,  we  should 
expect  the  same  explanation  in  both  cases;  and  so,  if  resistance 
to  conduction  does  not  explain  the  one,  it  probably  does  not 
explain  the  other.  Again,  as  regards  the  difference  in  reaction 
time  between  sound  and  light,  this,  likewise,  does  not  seem 
explicable  by  reference  to  the  greater  resistance  of  the  retina 
to  stimulation.  Further,  since  it  takes  as  long  to  become 
aware  of  the  cessation  as  of  the  beginning  of  a  very  weak 
sound,  the  long  time  required  for  the  awareness  of  either  can- 
not be  due  to  resistance  to  conduction.  And,  moreover,  this 
latter  fact  renders  it  probable  that  such  resistance  has  nothing 
to  do  with  the  explanation  of  the  long  time  required  for  a 
weak  stimulus  to  produce  its  maximal  sensory  effect. 

While  the  facts  of  cessation  reactions  thus  serve  to  call 


442  HERBERT  WOODROW 

attention  to  the  shortcomings  in  the  explanation  of  the  be- 
havior of  the  nervous  system  by  means  of  the  concept  of 
resistance,  it  must  be  admitted  that  there  exists  a  large  accu- 
mulation of  other  facts  which  likewise  greatly  impair  the 
plausibility  of  such  explanation.  Among  this  mass  of  evi- 
dence, we  may  cite  the  great  disproportion  and  lack  of  cor- 
relation between  energy  of  stimulus  and  energy  of  response. 
Even  more  conclusive  is  the  temporal  discrepancy.  This  dis- 
crepancy is  especially  striking  in  cases  where  psychocerebral 
processes  are  involved,  but  it  is  very  evident  even  in  reflexes, 
in  the  phenomenon  of  the  after-discharge.  Concerning  this 
phenomenon,  Sherrington  writes  as  follows:  "Tetanic  contrac- 
tion of  the  knee-flexor  muscles  of  the  dog  induced  by  brief  far- 
adization of  the  motor-nerve  usually  ceases  within  150  cr  of  the 
cessation  of  the  stimulation  of  the  nerve,  if  crude  condition  of 
fatigue,  etc.,  be  avoided.  The  contraction  of  these  same 
muscles,  when  induced  reflexly  by  a  similar  brief  stimulation? 
often  persists  for  5,000  <r  after  cessation  of  the  stimulus.1  Now 
this  great  duration  of  the  after-discharge  certainly  cannot  be 
explained  by  resistance  offered  at  the  synapse;  and  it  is  equally 
certain,  that  resistance  at  the  synapse  cannot  explain  the  rela- 
tion between  intensity  of  stimulus  and  both  duration  of  after- 
discharge  and  reflex  latent  time,  since  the  duration  of  the 
after-discharge  increases  with  intensity  of  stimulus,  while 
the  length  of  reflex  time  decreases.  It  would  be  easy  to  con- 
tinue, indefinitely,  these  instances  of  the  unsatisfactory  nature 
of  the  theory  that  the  action  of  the  nervous  system  is  ex- 
plicable merely  by  the  assumption  of  a  network  of  reflex 
paths,  which  offers  more  or  less  resistance  to  the  passage  of 
currents  from  the  sense-organs  to  the  muscle.  However, 
the  following  two  citations  will  suffice  to  indicate  the  dissatis- 
faction with  such  a  theory. 

Titchener  writes  as  follows:  "The  assumption  that  the 
reflex  arc  is  the  unit  of  nerve  function  evidently  makes  the 
brain  nothing  more,  in  principle,  than  a  mass  of  superposed 
reflex  arcs;  the  central  is  assimilated  to  the  peripheral  mech- 
anism; the  office  of  the  brain  is  to  perceive,  to  couple  up,  and 

1  Op.  tit.,  26. 


CESSATION  OF  STIMULI  443 

to  send  out.  But  this  view  that  the  nervous  system  is  a 
system  of  conduction,  a  sort  of  glorified  telephone  exchange, 
is  in  the  author's  opinion  wholly  inadequate  to  explain  the 
phenomena  of  mind.  The  theory  of  conduction,  with  ob- 
stacles or  easements  between  cell  and  cell,  must,  he  believes, 
be  replaced  by  a  theory  of  intracellular  change,  or  change 
within  the  cell-body;  and  if  this  is  the  case,  the  cortex  must 
be  regarded  rather  as  a  disjunction  of  the  reflex  arc  than  as  a 
switchboard  for  the  manifold  connection  of  afferent  with 
efferent  process."1 

Reference  may  be  made  also  to  the  views  of  the  physi- 
ologist, T.  Graham  Brown.  From  experiments  which  de- 
monstrated that  the  phenomenon  of  "narcosis  progression" 
in  the  cat  may  occur  at  a  depth  of  narcosis  at  which  the  spinal 
reflexes  are  abolished,  and  from  a  general  consideration  of  the 
facts  of  rhythmic  motor  phenomena,  Brown  concludes:  "The 
fundamental  unit  of  activity  in  the  nervous  system  is  not  that 
which  we  term  the  spinal  reflex."  He  says  that  his  experi- 
ments "show  the  independence  of  the  efferent  neurone,  and 
suggest  that  the  functional  unit  is  the  activity  of  the  inde- 
pendent efferent  neurone;  or  rather,  that  it  is  the  mutually 
conditioned  activity  of  the  linked  antagonistic  efferent  neu- 
rones (' half-centers')  which  together  form  the  'center,'  and 
they  also  suggest  that  the  primitive  activity  of  the  nervous 
system  is  seen  in  such  rhythmic  acts  as  progression  and 
respiration."2 

We  may  now  take  up  the  specific  and  difficult  question  of 
how  the  results  obtained  with  cessation  reactions,  discussed 
above,  are  to  be  explained.  We  have  seen  that  the  concept 
of  resistance  is  inadequate.  Is  it  possible  to  offer  a  more 
satisfactory  explanation?  While  in  the  present  state  of 
nerve  physiology  it  would  require  an  unprofitable  degree  of 
speculation  to  attempt  a  detailed  explanation,  it  does  seem 
feasible  to  indicate  at  least  the  general  direction  which  such 
an  explanation  must  take. 

1  'A  Text-Book  of  Psychology,'  1911,  489. 

2  T.  Graham  Brown,  'On  the  Nature  of  the  Fundamental  Activity  of  the  Nervous 
Centers,  Together  with  an  Analysis  of  the  Conditioning  of  Rhythmic  Activity  in  Pro- 
gression, and  a  Theory  of  the  Evolution  of  Function  in  the  Nervous  System,'  Journ.  of 
Physiol.,  Vol.  XVIII.,  1914. 


444  HERBERT  WOOD  ROW 

In  the  first  place,  it  seems  clear  that  a  greater  and  more 
distinctive  role  must  be  given  to  the  central  nervous  system, 
a  role  such  that  the  activity  of  the  central  nervous  system 
cannot  be  said  to  be  assimilated  to  the  peripheral.  To  sub- 
stantiate this  proposition  I  shall  refer  to  some  results  I  have 
already  published  elsewhere,  on  the  effect  of  the  preparatory 
interval  on  reaction  time.1  These  results  show  that  a  much 
longer  reaction  time  is  obtained  with  a  set  of  totally  irregular 
preparatory  intervals  of  varying  length,  or  with  very  long 
preparatory  intervals,  than  with  a  regularly  repeated  pre- 
paratory interval  of  two  seconds.  We  may  speak,  then,  of  the 
prolongation  in  reaction  time  produced  by  the  unfavorable 
preparatory  intervals.  Now  I  have  shown  that  with  weak 
intensity  of  stimulus  this  prolongation  is  very  much  greater 
than  with  strong  or  moderate  intensity;  and  I  have  pointed  out 
at  length,2  that  this  result  can  be  explained  only  on  the  assump- 
tion that  in  the  case  of  the  weaker  intensity  we  are  dealing  with 
a  lower  degree  of  attention.  Moreover,  it  is  known  that  with 
weakened  attention  we  have  lengthened  reaction  time.  We 
have,  then,  experimental  proof  that  a  large  part,  at  least,  of 
the  increase  in  reaction  time  with  decrease  in  intensity  is  due 
to  a  decrease  in  the  degree  of  attention.  This  conclusion  is  in 
general  agreement  with  the  explanation  long  since  advanced 
by  Wundt3  and  by  Martius.4  The  basis  of  the  explanation  is 
the  fact  that  intensity  of  stimulus  is  a  condition  determining 
the  degree  of  attention;  and  I  shall  attempt  to  show  how,  on 
this  basis,  we  can  explain  the  laws  of  cessation  reactions  as 
well  as  those  of  ordinary  reactions. 

Another  investigation  which  I  desire  to  mention,  is  one  on 
the  measurement  of  attention  as  it  occurs  in  reactions  to 
sound,  light,  and  touch,  using  as  the  measure  of  attention  the 
reciprocal  of  the  prolongation  in  reaction  time  produced  by 
unfavorable  preparatory  intervals.  While  these  results  may 
not  be  published  for  some  months  yet,  it  is  perhaps  permissible 

1  'The  Measurement  of  Attention,'  Psychol.  Monog.,  1915. 

2  Op.  «'/.,  Chap.  III. 

3  '  Physiologische  Psychologic/  5th  ed.,  1903,  Vol.  III.,  p.  430. 

4  'Ueber  den  Einfluss  der  Intensitat  der  Reize  auf  die  Reactionszeit  der  Klange,' 
Philos.  Stud.,  1892,  469-486. 


CESSATION  OF  STIMULI  445 

to  state  that,  in  the  case  of  nearly  all  of  the  twelve  subjects  so 
far  measured,  with  whom  over  15,000  reaction  times  have 
been  taken,  the  greatest  prolongation  occurred  with  light, 
the  next  greatest  with  sound,  and  the  smallest  with  touch; 
from  which  I  conclude  that  the  degree  of  attention  is  in  general 
lowest  in  the  case  of  light  reactions,  and  highest  in  the  case  of 
touch  reactions.  I  am  convinced  from  an  analysis  of  the 
data,  that  the  difference  in  degree  of  attention  in  these  cases 
is  sufficient  to  account  for  the  difference  in  simple  reaction 
time  that  occurs  with  difference  in  mode  of  stimulus. 

Befor  making  use  of  these  results  in  the  explanation  of  the 
phenomena  here  under  discussion,  I  wish  to  emphasize  the 
fact  that  the  reactions  in  human  reaction  time  experiments 
are  not  at  all  simple  reflexes.  Of  course,  cessation  reactions 
can  never  be  what  we  ordinarily  think  of  as  reflexes,  for  in 
this  case  there  is  no  stimulus,  merely  the  cessation  of  a 
stimulus.  One  cannot  mince  words  in  such  a  fashion  as  to 
say  that  the  cessation  of  stimulation  is  stimulation.  The 
reflex  theory  would  seem  entirely  inadequate  to  account 
even  for  the  existence  of  cessation  reactions.  A  similar  point 
could  be  made  in  the  case  of  reactions  to  a  mere  decrease 
in  intensity.  Moreover,  the  reaction  is  only  in  a  very 
secondary  manner  a  reaction  to  the  change  in  stimulus.  It 
is  primarily  brought  about  by  the  subject's  intention  to  react, 
which  in  turn  is  the  result  of  acceptance  of  instructions  given 
the  subject  a  considerable  time  before  the  reactions.  It  is 
further  evident,  at  least  in  the  case  of  weak  intensities,  that 
the  reaction  does  not  occur  until  the  subject  becomes  aware 
of  the  change  in  stimulus.  The  process  of  inhibition,  so  far 
as  can  be  judged  either  from  introspection  or  from  the  ob- 
jective reaction  times,  is  present  equally  in  cessation  and 
beginning  regctions.  In  both  cases  the  subject  is  prepared 
to  react  when  the  right  time  comes,  but  this  preparation  re- 
mains merely  a  preparation  until  then.  In  one  case  the  'right 
time'  means  when  the  subject  becomes  aware  of  the  stimulus, 
and  in  the  other  case,  when  he  becomes  aware  that  the  stimu- 
lus has  ceased.  No  satisfactory  account  of  the  reaction 
process  can  be  given  without  taking  into  consideration  this 
intention  and  preparation  to  react. 


446  HERBERT  WOODROW 

In  the  present  state  of  our  knowledge  of  the  physiology  of 
the  nervous  system,  it  is  impossible  to  say  definitely  in  what 
the  preparation  to  react  consists.  We  know  that,  in  practiced 
subjects,  it  is  often  unaccompanied  by  any  appreciable  ten- 
sion on  the  part  of  the  muscles  of  the  fingers  used  in  the 
reaction.  It  appears,  therefore,  not  to  consist  in  any  actual 
innervation  of  the  specific  reaction  movements.  We  know, 
too,  that  this  preparation  is  constantly  undergoing  certain 
irregular  variations  in  degree,  that  it  takes  about  two  seconds 
to  reach  its  maximum,  and  that  thereafter,  in  addition  to 
irregular  oscillations,  it  shows  a  definite  general  tendency  to 
weaken.  It  should  be  emphasized,  however,  that  a  certain 
degree  of  adaptation  may  be  maintained  throughout  a  con- 
siderable period  of  time.  We  know,  further,  that  this 
preparation  can  vary  in  degree  or  intensity,  and  that  the 
greater  the  intensity  of  such  preparation,  the  quicker  the 
reaction.  Without  attempting  to  go  into  details,  it  is  evident 
that  the  preparation  to  react  means,  on  the  nervous  side,  the 
presence  of  certain  nervous  energies  which  are  held  in  check, 
so  far  as  a  reaction  movement  is  concerned. 

There  is  energy,  the  intimate  nature  of  which  we  must 
admit  is  as  yet  unknown,  present  in  the  central  nervous  sys- 
tem and  temporarily  inhibited  in  some  way  from  producing 
the  reaction.  It  is  probable  that  this  energy  is  of  an  electri- 
cal nature,  and  that  it  always  involves  many,  if  not  all,  of 
the  neurones  of  the  central  nervous  system.  The  condition 
within  any  one  neurone  is  to  be  thought  of  as  interrelated 
with  the  conditions  within  all  the  others,  so  that  there  is 
always  involved  an  immensely  complicated  and  widespread 
system  of  energies,  including,  perhaps,  both  potential  chemi- 
cal energies  and  electrical  activities.  So  long  as  the  subject's 
state  is  merely  one  of  preparation  for  the  reaction,  it  must  be 
supposed  that  the  interrelated  cortical  energies,  while  by  no 
means  entirely  suppressing  each  other  (for  the  subject  would 
then  be  unconscious),  yet,  interact  in  such  a  way  that  some 
sort  of  equilibrium  occurs  at  the  point  of  exit  of  the  motor 
pathway  for  the  reaction  movement.  The  existence  of  this 
equilibrium,  as  respects  the  reaction  movement,  is  evident 


CESSATION  OF  STIMULI  447 

merely  because  the  reaction  movement  does  not  occur,  ordi- 
narily, until  after  the  stimulus  which  comes  at  the  end  of  the 
preparatory  interval. 

The  mere  fact  that  both  beginning  and  cessation  reactions 
are  possible,  shows  that  this  equilibrium  may  be  upset  either 
by  the  beginning  of  some  new  disturbance,  or  by  the  cessation 
of  one.  There  is  no  theoretical  difficulty  here  such  as  we 
encountered  in  attempting  to  explain  both  the  laws  of  cessa- 
tion and  beginning  reactions  by  reference  to  the  concept  of 
resistance.  Different  instructions  set  up  different  central 
adjustments,  and  while  these  adjustments  in  both  cases  con- 
sist in  a  system  of  activities  which  are  in  equilibrium  so  far 
as  the  reaction  movement  is  concerned,  the  pattern  of  the 
adjustment  must  be  different  in  the  two  cases;  so  that,  in  one 
case,  the  occurrence  of  a  new  excitation  destroys  the  existing 
equilibrium,  while,  in  the  other,  the  new  excitation  merely 
serves  to  increase  the  intensity  of  activity  of  a  different  sys- 
tem, the  equilibrium  of  which,  however,  is  not  upset  until 
this  excitation  ceases.  The  widespread  system  of  cortical 
energies  takes  on  such  a  form,  as  the  result  of  the  instructions, 
that  upon  the  occurrence  of  the  proper  sensory  disturbance, 
some  of  this  cerebral  energy  is  released  for  the  work  of  inner- 
vation  of  the  reaction  movement. 

The  energy  used  in  the  innervation  of  the  reaction  move- 
ment is  not  the  energy  of  the  excitation  set  up  in  the  sensory 
nerve  by  the  stimulus;  it  is  energy  already  present  in  the  cen- 
tral nervous  system  before  the  stimulus  acts.  In  a  reflex, 
as  commonly  described,  the  outgoing  energy  is  merely  the 
redirected  incoming  energy.  This  remains  true,  even  though 
we  further  add  that  reflexes  may  inhibit  or  reinforce  one 
another.  The  present  view,  however,  regards  the  central 
nervous  system  as  not  merely  a  network  of  paths,  but  also  as 
a  vast  system  of  interrelated  energies,  potential  and  other- 
wise. A  disturbance  produced  in  this  system  is  not  con- 
ducted through  it;  it  causes  a  readjustment  of  the  system, 
which  readjustment  may  (or  may  not,  so  far  as  is  known) 
result  in  the  release  of  energy  for  the  work  of  motor  inner- 
vation. It  is  difficult  to  see  how,  on  any  other  theory,  we 


448  HERBERT  WOODROW 

can  account  even  for  the  fact  of  cessation  reactions.  It  has 
already  been  pointed  out  that  it  is  impossible  to  think  of  the 
cessation  reaction  as  a  simple  reflex,  for  in  this  case  there  is 
no  stimulus,  but  merely  the  cessation  of  a  stimulus.  On  the 
other  hand  it  is  not  difficult  to  understand  that  a  change  in 
any  part  of  a  system  of  energies  may  upset  the  balance  of  the 
system  as  a  whole,  whether  the  change  in  question  be  an  in- 
crease or  decrease  of  activity. 

The  process  by  which  the  change  in  sensory  excitation 
disturbs  the  preexisting  cerebral  system  is  in  part,  no  doubt, 
the  physiological  process  corresponding  to  becoming  aware  of 
the  change.  Even  if  actual  awareness  were  not  a  necessary 
condition  of  the  reaction,  it  seems  altogether  probable  that  a 
nervous  process  identical  in  nature  to  that  which  underlies 
awareness,  though  less  in  degree,  must  precede  the  reaction 
movement.  The  process  which  underlies  awareness  of  the 
cessation  of  a  stimulus  must  consist  in  an  effect  produced  by 
this  sensory  change  upon  more  or  less  widely  distributed 
parts  of  the  cerebral  cortex.  It  could  not  consist  in  the  local 
sensory  effect,  for  this  is  merely  a  cessation.  It  is  probably 
no  less  true  that  the  awareness  of  the  occurrence  of  the  stimu- 
lus involves  changes  in  the  entire  cerebral  activity.  We 
know  from  introspection  that  any  new  perception  coming 
into  the  field  of  consciousness  ordinarily  modifies  the  pattern 
of  consciousness  as  a  whole. 

It  is  clear  that  these  central  nervous  processes  in  which 
alone  is  to  be  found  the  explanation  of  the  phenomena  dis- 
cussed in  the  preceding  pages,  are  in  large  part  identical  with 
those  of  attention  or  awareness;  but  that  these  central  proc- 
esses are  all  such  that  they  may  be  subsumed  under  this 
heading  is  improbable.  They  are  quite  likely  very  complex. 
It  may  be,  for  instance,  that  in  addition  to  the  physiological 
process  underlying  awareness,  there  occurs  another  process 
which  consists  in  the  release  of  so-called  determining  tend- 
encies. 

We  may  now  ask  why  a  small  change  in  the  sensory  ex- 
citation, whatever  this  may  mean  in  terms  of  nerve  physiol- 
ogy, should  bring  about  the  required  disturbance  in  the  pre- 


CESSATION  OF  STIMULI  449 

existing  system  of  cerebral  energies  so  much  more  slowly 
than  a  large  one,  regardless  of  the  direction  of  change.  This 
is  satisfactorily  explained  as  due  to  the  inertia  of  the  pre- 
existing cortical  adjustment.  Of  course  we  do  not  know  the 
intimate  nature  of  the  cortical  changes  brought  about  by  the 
sensory  change;  but  that  there  is  work  to  be  done  in  bringing 
about  these  charges,  and  that  this  work  would  be  done  more 
slowly  by  a  small  local  disturbance  than  by  a  big  one,  seem 
to  me  unquestionable  propositions.  I  have  already  argued 
that  the  cortical  processes  in  question  are  largely  those  under- 
lying the  phenomenon  of  attention.  It  is  well  known  that 
these  processes  require  considerable  time;  e.  g.,  it  is  well  es- 
tablished that  maximal  adaptation  of  attention  requires  about 
two  seconds.  There  is,  moreover,  no  difficulty  in  under- 
standing why  the  reaction  time  to  the  cessation  of  the  ex- 
citation equals  the  reaction  time  to  its  occurrence,  no  matter 
what  the  intensity  of  the  stimulus.  The  size  of  change  in 
sensory  excitation  is  of  course  the  same,  whether  the  change 
be  due  to  the  occurrence  or  the  cessation  of  the  stimulus.  The 
direction  of  change  of  the  excitation  need  not  affect  either 
the  size  or  rate  of  change.  The  rate  of  change  in  the 
sensory  cortical  excitation,  then,  we  assume  to  be  prac- 
tically the  same  at  both  the  occurrence  and  cessation  of  the 
excitation;  and,  further,  we  assume  that  so  long  as  the  in- 
tensity of  the  preparatory  adjustment  remains  constant,  the 
time  required  for  the  disturbance  or  release  of  the  preadjusted 
system  of  cortical  energies  varies  with  the  size  and  rate  of  change 
in  excitation,  which  brings  about  this  release.  The  difference 
in  direction  of  the  change  in  excitation  is  counterbalanced 
by  the  difference  in  the  nature  of  the  preadjustment. 

The  next  question  to  be  answered  is  why  light  reactions,  at 
moderate  intensities  of  stimuli,  are  longer  than  sound  re- 
actions. This  is  easily  accounted  for  on  the  hypothesis  that 
the  cortical  preadjustment  is  less  effective  in  the  case  of 
light  than  in  the  case  of  sound.  The  lesser  effectiveness  of 
preadjustment,  in  the  case  of  light  reactions  as  compared  with 
sound  or  touch  reactions,  may  possibly  be  accounted  for  by 
the  fact  that  the  adjustment  of  the  sense-organ  in  the  case  of 


45°  HERBERT  WOODROW 

vision — including  the  control  of  convergence,  accommodation, 
winking,  proper  direction  of  head,  etc. — is  more  elaborate 
than  in  the  case  of  hearing  or  touch,  where  no  sensory  ad- 
justments of  any  great  consequence  are  required.  The  ex- 
penditure of  energy  on  the  sensory  adjustment  may  detract 
from  the  adequacy  of  the  central  cerebral  adjustment  as  a 
preparation  for  the  reaction  movement.  Whatever  be  the 
cause  of  the  better  cerebral  adjustment  in  the  case  of  sound 
and  touch  reactions,  the  fact  of  such  better  adjustment  is 
evident;  for  upon  no  other  assumption  can  we  explain  the 
result  already  mentioned,  that  light  reactions  are  prolonged 
more  by  the  use  of  unfavorable  preparatory  intervals  than 
are  sound  or  touch  reactions.  I  have  shown  elsewhere,  that 
the  prolongation  produced  in  reaction  time  by  unfavorable 
preparatory  intervals  is  due,  solely,  to  the  effect  of  such  as  a 
detractor  of  attention.  This  detraction  effect  occurs  in  ac- 
cordance with  the  law  that  the  prolongation  produced  varies 
inversely  with  the  degree  of  attention  acted  upon.  Accord- 
ingly, since  the  prolongation  in  reaction  time  produced  by 
unfavorable  preparatory  intervals  is  greater  in  the  case  of 
light  reactions  than  in  touch  or  sound,  it  follows  that  the 
degree  of  attention  in  the  former  is  less  than  in  the  latter. 
On  the  cerebral  side  we  may  substitute  effectiveness  of  cerebral 
adjustment  for  degree  of  adaptation  of  attention. 

CONCLUSIONS 

1.  The  experiments  here  reported  show  that  the  reaction 
time  to  the  cessation  of  a  sound  or  light  stimulus  is  in  all 
cases  the  same  as  the  reaction  time  to  the  beginning  of  that 
stimulus.     This  statement  includes  the  following  two  corol- 
laries,    (i)  The  same  difference  between  reaction  times  to 
sound  and  light  exists  in  the  case  of  reactions  to  their  cessa- 
tion as  in  the  case  of  reactions  to  their  beginning.     (2)  The 
lengthening  in  reaction  time  due   to  a  decrease  in  intensity 
of  stimulus  is  equal  in  amount,  and  follows  the  same  law,  in 
the  case  of  both  beginning  and  cessation  reactions. 

2.  The  above  mentioned  similarity,  in  the  variation  of 
both  beginning  and  cessation  reactions  with  mode  and  with 


CESSATION  OF  STIMULI  451 

intensity,  cannot  be  explained  either  by  the  hypothesis  of 
variation  in  the  latent  period  of  stimulation  of  the  sense- 
organ,  or  by  the  hypothesis  of  variation  in  the  resistance 
offered  by  the  synapses.  Likewise,  this  similarity  cannot  be 
adequately  explained  on  the  commonly  accepted  hypothesis 
that  all  nervous  action  consists  essentially  in  conduction  of 
nervous  impulses  from  the  sense-organ  to  the  muscle  along 
arcs  which  offer  varying  amounts  of  resistance.  On  the  other 
hand,  the  facts  on  beginning  and  cessation  reactions  are  in- 
compatible with  such  an  hypothesis. 

3.  The  explanation  of  the  experimental  data  presented  in 
the  preceding  pages,  while  at  present  impossible  in  detail, 
seems  to  require  us  to  regard  the  central  nervous  system  as  not 
merely  a  network  of  paths,  but  also  as  the  seat  of  a  complex 
system  of  interrelated  activities  and  potential  energies  which 
is  disturbed  throughout  by  any  change  in  any  part  of  the 
system.     The  fact  of  cessation  reactions  cannot  be  adequately 
explained  without  postulating  such  a  central  system  of  ener- 
gies, the  balance  of  which  may  be  upset  by  either  an  increase 
or  decrease   of  activity  in   any  part  of  the   system.     The 
pattern  of  the  preexisting  system  differs  in  beginning  reactions 
from  that  in  cessation  reactions  in  such  a  manner  that,  in 
beginning  reactions,  the  same  effect  is  produced  by  the  rise 
of  the  excitation  as  is  produced  in  cessation  reactions  by  its 
fall.     A  small  change  in  excitation  disturbs  the  preexisting 
cortical  system  so  as  to  bring  about  the  reaction  movement 
more  slowly  than  does  a  large  one — not  because  of  resistance 
to  its  conduction,  but  because  of  the  inertia  of  the  preexisting 
central  system.     The  reaction  time  to  light,  both  for  cessation 
and  beginning  reactions,  is  longer  than  for  sound  because  of  an 
inferior  preadjustment  of  the  cerebral  mechanism.     In  all 
cases  the  reaction  results  from  the  release  of  energy  already 
within    the    nervous    system   before    the   occurrence   of   the 
stimulus;  and  is  not  due  to  the  mere  redirection  or  modifica- 
tion of  the  incoming  sensory  excitation. 

4.  The  physiological  disturbance  of  the  central  nervous 
system  here  involved  is  in  large  part,  though  not  entirely, 
that  which  underlies  the  process  of  becoming  aware  of  a 


45 2  HERBERT  WOODROW 

stimulus  or  of  attending  to  it.  This  is  shown  by  the  fact  that 
the  degree  of  attention,  in  the  case  of  reactions  to  a  weak 
stimulus,  is  less  than  that  in  the  case  of  reactions  to  a  strong 
stimulus,  and  also,  less  in  the  case  of  reactions  to  light  than 
in  the  case  of  reactions  to  sound  or  touch. 


FACILITATION   AND   INHIBITION  OF   MOTOR 

IMPULSES 

A    STUDY    IN    SIMULTANEOUS    AND    ALTERNATING    FINGER 

MOVEMENTS 

BY  HERBERT  SIDNEY  LANGFELD 
Harvard  University 

DESCRIPTION  OF  EXPERIMENTATION 

The  purpose  of  the  investigation1  was  to  ascertain  the 
facilitating  and  the  inhibitory  effect  of  successive  and  simul- 
taneous muscular  impulses  in  the  movements  of  the  several 
fingers  of  both  the  right  and  left  hands.  The  data  have  also 
been  arranged  to  show  the  effect  of  practise  and  fatigue  and 
the  relation  of  the  movements  of  the  fingers  of  the  right  hand 
to  those  of  the  left  hand. 

The  instrument  used  was  similar  to  that  of  the  Whipple 
tapping-board2  as  will  be  seen  from  the  cut,  p.  476.  In  place 
of  a  metal  stylus,  a  ring  was  worn  on  the  finger.  This  was 
insulated  by  rubber  tubing  except  on  the  under  part  where 
a  metal  peg  protruded  and  made  an  electric  contact  with  the 
metal  base  of  the  board.  A  light  flexible  wire  ran  from  the 
ring  to  an  electric  marker  which  registered  the  contact  on  a 
kymograph.3  In  order  to  obtain  a  free  and  natural  movement 
of  the  fingers,  the  hand  rested  on  a  curved  block  of  wood, 
and  was  thus  slightly  vaulted.  The  tips  of  the  fingers  and 
cushions  of  the  palm  of  the  hand  rested  on  the  board.  The 
arm  rested  on  the  table,  several  of  the  subjects  using  a  cushion 
for  greater  comfort. 

It  was  deemed  of  importance  that  the  height  of  the  finger 

1  The  experiments  were  conducted  in  the  Harvard  Psychological  Laboratory 
during  the  academic  year,  1913-14.     Trial  experiments,  not  here  reported,  were  made 
the  previous  year. 

2  'Manual  of  Mental  and  Physical  Tests,  Simpler  Processes,'  p.  131. 

8  It  was  under  similar  conditions  that  one  of  the  first  tapping  tests — that  of  von 
Kries — was  performed,  'Zur  Kenntniss  der  willkiirlicher  Muskelthatigkeit,'  Arch.  f. 
Anatomic  u.  Physiologie,  1886,  Sup.  Band,  pp.  1-16. 

453 


454  H.  S.  LANGFELD 

movement  should  be  constant  so  that  there  could  be  no  doubt 
that  differences  in  the  rate  of  tapping  were  not  due  to  changes 
in  the  length  of  stroke.  A  bar  was  therefore  placed  4  cm. 
above  the  board  and  the  subject  was  instructed  to  hit  the 
bar  at  each  stroke.  The  bar  met  the  finger  slightly  below 
the  second  joint,  and  care  was  taken  that  it  should  always 
strike  at  approximately  the  same  spot  throughout  the  tests. 
This  arrangement  worked  very  well,  the  subject  soon  becom- 
ing used  to  the  task.  The  movement  thus  remained  more 
nearly  voluntary  than  would  probably  have  been  the  case 
if  the  finger  had  not  had  to  touch  the  bar.1  The  hand  was 
not  strapped  to  the  board  as  it  was  soon  evident  that  the 
subject  could  keep  his  hand  and  arm  still,  and  if  there  did 
happen  to  be  a  slight  movement,  his  attention  was  called  to 
it  at  once;  nor  was  the  tapping  continued  to  that  period  of 
fatigue  when  the  subject  in  seeking  relief  begins  to  use  other 
muscle  groups  of  the  arm.  Any  slight  error  that  might  have 
crept  in  could  not  be  as  great  as  would  have  been  the  danger 
to  the  result  caused  by  the  binding  of  the  muscles.  The 
only  muscles  used,  therefore,  were  the  extensors  and  the 
flexors  of  the  phalanges.  These  muscles  pass  from  their 
origin  in  the  forearm  over  the  wrist  joint  to  the  phalanges 
and  at  the  end  of  the  grasping  movement  there  is  a  tendency 
for  them  to  flex  the  hand,  which  is  inhibited  by  the  synergic 
muscle  of  the  wrist. 

The  time  in  two-second  periods  was  marked  on  the  drum 
at  the  beginning  of  each  set  of  trials  by  a  marker  actuated 

1  In  regard  to  the  length  of  stroke,  von  Kries  writes,  loc.  cit.,  page  4,  "Der  Umfang 
der  Bewegungen  ist  auf  die  Dauer  von  nur  geringem  Einfluss;  doch  scheint  es,  dass  die 
Bewegungen  von  einem  gewissen  mittleren  Umfamg  am  schnellsten  ausgefiihrt  werden 
konnen  und  sowohl  die  sehr  kleinen  als  die  sehr  grossen  ein  wening  langer  dauern." 
Bryan  ('On  the  Development  of  Voluntary  Motor  Ability,'  Amer.  Jour,  of  Psychol., 
5,  1892,  p.  150)  is  in  agreement  with  von  Kries  as  to  the  slight  effect  of  change  of  am- 
plitude. Max  Isserlin  states  that  "...  die  Tendenz  besteht,  trotz  abnehmender 
Geschwindigkeit  die  Bewegungszahl  konstant  zu  erhalten.  Diese  wird  zuletzt  herab- 
gesetzt"  ('Ueberden  Ablauf  einfacher  willkiirlicher  Bewegungen,'  Psych.  Arbeiten,  6 
1910,  p.  186).  From  this  we  may  conclude  that  the  change  in  amplitude  conceals  the 
fatigue  as  measured  by  the  rate  of  tapping  alone.  It  was  also  found  in  the  preliminary 
tests  before  the  control  bar  was  used  that  there  was  a  strong  tendency  for  several 
subjects  to  execute  a  series  of  quick  reflex  movements  similar  to  a  tremble  which  greatly 
increased  the  tapping  rate  and  seemed  difficult  at  times  to  avoid. 


FINGER  MOVEMENTS  455 

by  the  laboratory  clock.    When  both  hands  were  used,  a  board 
was  employed  for  each  hand. 

There  were  four  subjects  who  will  be  referred  to  as  A,  B,  C, 
D.  A  and  B  were  advanced  graduate  students;  C  and  D  under- 
graduates. A  and  D  were  very  athletic,  B  less  so  and  C  the 
least  strong  of  the  four.  The  experiments  were  made  in  the 
morning,  the  subjects  coming  always  at  the  same  hour.  As 
a  rule,  there  was  a  week's  intermission  between  each  set  of 
trials.  The  period  of  tapping  for  all  fingers  and  all  combina- 
tions of  movements  was  30  seconds  with  a  two  seconds' 
pause  between  the  members  of  a  series  and  a  five  minutes' 
pause  between  the  series.  The  finger  movements  examined 
were  as  follows:  During  the  first  half  year,  the  subject  began 
by  tapping  with  his  right  index  finger  (Ri).  This  was 
followed  by  the  second  finger  of  the  same  hand  (R2).  Then 
these  two  fingers  were  tapped  alternately  (A),  a  movement 
similar  to  the  walking  movement,  that  is,  Ri  was  raised  as 
R2  was  lowered,  the  two  fingers  passing  each  other  in  the 
middle  of  the  stroke.  There  then  followed  what  may  be 
termed  complete  alternation  (CA).  Ri  made  a  complete 
stroke  up  and  down  before  R2  began.  The  signal  for  a  finger 
to  begin  was  the  return  of  the  other  finger  to  the  starting 
point  in  the  manner  of  a  relay  race,  Ri  went  up  and  down 
then  R2  went  up  and  down,  etc.  Finally  Ri  and  R2  tapped 
simultaneously  [S(Ri  R2)].  This  completed  the  series.  After 
a  five  minutes'  pause,  the  series  was  repeated  in  the  same 
order.  On  alternate  weeks,  the  order  of  the  series  was 
reversed,  beginning  with  S  and  ending  with  Ri.  At  the 
beginning  of  the  year  the  left-hand  fingers  were  tapped  in 
the  same  manner  as  the  right  and  again  for  one  series  about 
six  weeks  later,  in  order  to  ascertain  if  there  was  any  transfer 
of  practise.  During  the  second  half  of  the  year,  both  hands 
were  used.  The  series  began  with  the  right  index  finger 
alone.  Then  followed  the  left  index  finger  alone  (Li)  and 
then  both  simultaneously  [S(Ri  Zi)];  and  then  the  second 
finger  of  the  right  hand  (R2)  alone  for  thirty  seconds,  followed 
by  the  second  finger  of  the  left  hand  (Z,2)  alone  and  then  both 
simultaneously  [S(R2  L.2)].  This  series  was  repeated  and 


456  H.  S.  LANGFELD 

the  order  reversed  on  alternate  weeks.  A  few  series  were 
also  made  with  Ri  and  L^  and  [S(Ri  £2)]  and  Ri  and  L\ 
and  [S  (Ri  £4)]. 

SIMULTANEOUS  MOVEMENT 

The  final  averages  have  been  gathered  of  the  simultaneous 
tapping  of  the  pairs  of  fingers  of  both  hands  and  have  been 
placed  together  in  Table  IV.1  for  convenience  of  comparison. 
In  the  second  and  fourth  columns  for  each  subject  are  the 
rates  of  tappings  for  30"  for  the  fingers  separately,  and  in 
the  sixth  column,  the  rates  when  tapped  together.  In  the 
seventh  column  is  the  difference  in  rate  of  the  two  fingers, 
and  in  the  eighth,  the  difference  between  the  rate  of  the 
simultaneous  tapping  and  the  rate  of  the  slower  finger  when 
tapping  alone.  Examining  first  the  two  fingers  of  the  same 
hand,  J^i  and  .#2,  we  find  the  interesting  fact  that,  with  all  the 
subjects  the  two  fingers  are  moved  more  rapidly  together 
than  the  slower  finger  alone  and  in  the  case  of  A  faster  even 
than  the  faster  finger  by  a  considerable  amount.  With  B,  S 
is  one  stroke  faster  than  the  faster  finger.  A  similar  relation 
holds  with  the  symmetrical  fingers  of  the  left  hand  (second 
horizontal  column).  Here  in  fact  in  the  case  of  all  but  J?, 
who  shows  little  change,  the  two  fingers  are  tapped  faster 
together  than  either  of  the  separate  fingers.  In  Tables  I., 
II.  and  III.  the  maximal  rates  of  tapping  are  in  heavy  type  and 
may  be  readily  compared.  For  the  right  hand  the  highest  S 
is  greater  than  the  highest  Ri  or  R2  for  all  subjects  but  C. 
For  the  left  hand  the  highest  S  is  greater  than  the  highest  Li 
or  L2  for  all  the  subjects.  The  explanation  which  suggests  itself 
is  that  the  two  fingers  being  very  closely  related,  an  impulse 
to  one  tends  to  influence  the  other,  since  a  strong  coordination 
has  probably  been  induced  by  the  grasping  movement.  In 
the  single  movement  the  other  finger  must  be  voluntarily 
held  down  and  this  slows  up  the  action  of  the  moving  finger. 
When  both  fingers  are  moved  together  this  inhibition  is 
removed  and  they  both  move  faster,  unless  one  is  much  slower 
than  the  other,  when  it  acts  as  an  inhibition.  It  is  possible 

1  These  averages  have  been  taken  from  Tables  I.,  II.  and  III. 


FINGER  MOVEMENTS 


457 


that  with  the  left  hand,  the  inhibition  of  the  idle  finger  is 
more  difficult  than  with  the  right  hand  due  to  less  practise. 
This  would  account  for  S  being  greater  than  the  single  tapping 

TABLE  I 


Subject  A 

Subject  B 

Subject  C 

Subject  D 

No. 

Ri 

Ra 

A 

c,|, 

Ri 

Ra 

A 

CA 

S 

Ri 

Ra 

A 

CA 

S 

Ri 

Ra 

A 

CA 

5 

I 

154 

I6S 

120 

37172 

137 

116 

36 

163 

178 

I48 

44 

23 

160  139 

161 

106 

25 

172 

2 

ISS 

170 

121 

39 

192 

168 

I4I 

131 

34 

170 

161 

162 

24 

174  149 

158 

112 

34 

i74 

3 

153 

I6S 

117 

34 

187 

H3 

I38 

131 

4i 

161 

119 

121 

68 

27 

H4  137 

152 

1  08 

32 

151 

4 

I84 

IQO 

126 

40 

196 

172 

161 

136 

40 

iSS 

115 

117 

31 

132  147 

162 

112 

36 

157 

5 

H5 

153 

118 

40 

178 

173 

152 

140 

35 

170 

174 

162 

57 

29 

175  HI 

I48 

I04 

34 

154 

6 

146 

115 

46 

187 

170 

164 

H3 

42 

188 

193 

ISI 

67 

27 

190  136 

I46 

102 

36 

138 

7 

159 

171 

119 

43 

167 

178 

160 

133 

39 

166 

191 

168 

56 

26 

168  133 

152 

109 

35 

135 

8 

170 

166 

136 

47 

197 

166 

170 

141 

42 

164 

194 

165 

66 

26 

174  136 

153 

103 

40 

134 

9 

137 

145 

1  20 

43 

163 

160 

151 

127 

40 

181 

178 

161 

54 

24 

167  121 

I46 

103 

35 

148 

10 

154 

143 

130 

44 

179 

189 

171 

168 

59 

187 

159 

59 

25 

186 

145 

105 

36 

148 

ii 

ISS 

159 

131 

37,150 

178 

178 

133 

37 

173 

142 

168 

H3 

40 

146 

12 

160 

150 

137 

40  168 

192 

186 

154 

45 

181 

141 

160 

IOQ 

40 

146 

13 

141 

136 

139 

41  176 

169 

161 

142 

33 

!69 

145 

156  105 

42 

148 

14 

159  ISO 

137 

46169 

170 

170 

138 

40,177 

129 

158114 

34 

148 

IS 

157 

161 

133 

45 

161 

178 

178 

ISS 

44 

1  88 

129 

151  106 

36 

138 

16 

IS4 

150 

134 

52 

182 

1  80 

175 

153 

53 

178 

135 

148  101 

32 

149 

17 

1  86 

177 

iSi 

4i 

187 

139 

162  103 

38 

158 

18 

185 

185 

144 

40 

198 

143 

153  "0 

35 

155 

Av. 

ISS 

158 

127 

42 

176 

173 

164 

141 

41 

174 

169 

iSi 

59 

26 

164 

I38 

154 

107 

36 

ISO 

Ri 

toS 

149 

iS3 

125 

42 

177 

174 

160 

140 

40 

178 

178 

157 

56 

25 

175 

135 

153 

106 

35 

154 

S  to 

Ri 

161 

164 

129 

42 

176 

173 

168 

142 

42 

170 

159 

142 

63 

27 

147 

I38 

156 

108 

36 

144 

m.v. 

7 

10 

8 

4 

ii 

9 

13 

9 

4 

9 

22 

H 

6 

2 

17 

6 

5 

3 

3 

8 

of  either  finger  for  the  two  subjects  who  did  not  show  this 
with  the  right  hand. 

Is,  however,  the  release  of  inhibition  due  to  the  close 
relationship  of  the  fingers  the  only  factor  which  causes  the 

TABLE  II 


No. 

Subject  A 

Subject  B 

Subject  C 

Subject  D 

Li 

L2 

A 

CA 

5 

Li 

La 

A 

CA\  S 

Li 

La 

A 

CA 

5 

Li 

La 

A 

CA 

5 

I 

1  10 

128 

46 

27 

135 

134 

131 

III 

32*131 

"5 

"3 

44 

24 

116 

134 

120 

90 

30 

156 

2 

"S 

140 

55 

36 

164 

139  H3 

119 

35  HO 

III 

H7 

58 

27 

128 

137 

132 

105 

34 

H3 

3 

107 

128 

56 

30 

133 

143,142 

119 

34  131 

114 

117 

8z 

22 

125 

137 

135 

104 

38 

127 

4 

"3 

125 

68 

37 

141 

154  146 

114 

36  142 

H3 

"3 

71 

25 

120 

151 

139 

106 

35 

HI 

5 

107 

122 

59 

32 

133 

149  I48 

US 

44  155 

1  10  109 

S3 

28 

118 

137 

I2S 

97 

34 

134 

6 

H3 

119 

68 

36 

140150149 

H3 

49  164 

no 

I2O 

59 

28 

121 

I36 

133 

98 

38 

142 

Av. 

112 

127 

59 

33 

141  145 

143 

US 

38  144 

112 

"5 

61 

26 

121 

139 

131 

IOO 

35 

I40 

m.v. 

5 

5 

6 

3 

7l  6 

4 

2 

5  10 

2 

3 

10 

2 

3 

4 

5 

5 

2 

7 

H.  S.  LANGFELD 


increase  especially  in  the  slower  finger?  Does  not  one 
impulse  directly  influence  the  other  when  discharged  simul- 
taneously, not  only  exciting  an  inhibitory  effect  in  the  case 
of  the  slower  movement,  but  a  facilitating  effect  in  the  case 
of  the  faster?  To  answer  this  question  symmetrical  fingers 
of  the  two  hands,  Ri  and  Li  and  R2  and  Z,2  were  tapped  simul- 
taneously. Here  there  cannot  be  the  same  strong  natural 
tendency  to  move  the  two  fingers  simultaneously  as  is  prob- 

TABLE  III 


Subject  A 

Subject  B 

Subject  C 

Subject  D 

No. 

Ri 

LI 

s 

Ra 

La 

5 

Ri 

Li 

s 

Ra 

La 

^ 

Ri 

Li 

S 

Ra 

La 

s 

Ri 

Li 

s 

Ra 

La 

I 

I46 

117 

137 

H7 

124 

1.1.1 

172 

146 

111 

170 

143 

163 

179 

107 

118 

168 

114 

1.33 

130 

124 

128 

111 

128  I 

2 

117 

119 

110 

111 

123 

184 

1.13 

167 

177 

111 

174 

191 

114 

127 

167 

116 

122 

131 

I2S 

128 

111 

1321 

3 

164 

128 

140 

117 

ii;6 

173 

144 

163 

174 

I48 

ill 

190 

122 

171 

124 

139 

128 

127 

112 

1301 

4 

119 

Ht; 

149 

168 

140 

H8 

193 

146 

169 

1  8O 

I48 

114 

200 

116 

123 

1  80 

126 

147 

140 

133 

I64 

1341 

S 

131 

129 

1  16 

131 

174 

110 

177 

I48 

161; 

173 

123 

131 

169 

117 

131 

133 

132 

131 

113 

6 

160 

131 

146 

173 

141 

112 

1  80 

H8 

162 

174 

114 

161 

192 

in 

124 

184 

124 

141 

138 

136 

130 

H8 

140 

7 

169 

117 

1.12 

170 

1.1.1 

192 

159 

17.1 

18.1 

1.14 

1.19 

180 

H.1 

123 

169 

114 

120 

142 

132 

132 

1.13 

127 

8 

177 

130 

144 

160 

132 

110 

203 

113 

167 

186  160 

170 

172 

116 

123 

120 

IOI 

134 

142 

144 

136 

113 

131 

9 

167 

133 

163 

163 

1.10 

1  80 

i.17 

1  86  149 

1.16 

182 

123 

134 

I69 

12.1 

134 

1.38 

132 

128 

1.17 

132 

10 

162 

138 

160 

132 

1  66 

187 

148 

1.17 

172 

146 

1,1.3 

204  119 

122 

162 

III 

118 

138 

129 

130 

1.13 

I.3I 

ii 

IS8 

H9 

T43 

167 

123 

151 

193 

1.13 

170 

1  80 

148 

162 

176 

121 

120 

1.16 

118 

124 

1.3.1 

140 

i33 

12 

162 

125 

110 

i?4 

i,11 

200 

148 

178 

185 

112 

182 

179 

124 

132 

164 

135 

133 

143 

133 

141 

163 

137 

J3 

171 

141 

162 

173 

112 

161 

H 

1  86 

152 

162 

172 

I58 

160 

Av. 

160 

125 

H3 

161 

129 

155 

185 

150 

164 

178 

ISI 

162 

185 

117 

125 

165 

118 

130 

138 

133 

131 

155 

1331 

Ri  toS 

155 

129 

140 

158 

I3I 

156 

179 

150 

161 

I7S 

ISO 

162 

187 

116 

126 

170 

118 

130 

135 

129 

129 

154 

1331 

S  toRi 

166 

122 

146 

164 

129 

154 

192 

ISO 

170 

180 

152 

163 

181 

118 

124 

160 

118 

130 

140 

136 

i34 

156 

1321 

m.r. 

7 

6 

7 

8 

5 

4 

8 

4 

5 

S 

4 

6 

9 

4 

4 

10 

6 

7 

4 

S 

3 

3 

4 

ably  the  case  with  the  fingers  just  examined.  In  Table  IV. 
we  find  that  with  three  of  the  subjects  for  both  sets  of  fingers 
there  is  an  increase  in  the  tapping  of  the  slow  and  a  decrease 
in  that  of  the  fast  finger.  In  the  case  of  both  A  and  B  the 
simultaneous  tapping  approaches  the  average  of  the  two 
fingers.  For  C  the  effect  of  the  faster  finger  is  not  so  great 
and  the  increase  of  speed  of  the  slower  finger  is  below  that  of 
A  and  B.  A  further  peculiarity  of  this  subject  to  be  discussed 
later  offers  an  explanation  for  this.  For  D  the  simultaneous 
tapping  for  both  pairs  is  about  the  same  as  the  slower  finger. 
The  difference  between  Ri  and  Li,  however,  is  very  slight 


FINGER  MOVEMENTS 


459 


and  between  R2  and  Z,2  less  than  with  any  of  the  other  sub- 
jects. This  difference  is  an  important  factor  as  will  be  seen 
below  (p.  460).  It  is  evident,  however,  that  with  three  of 
the  subjects  the  rapidity  of  the  movement  is  increased  by  the 
simultaneous  exercise  of  a  more  rapid  movement  taking  place 
in  a  symmetrical  part  of  the  opposite  side  of  the  body. 
The  more  rapid  movement,  on  the  other  hand,  is  to  an  extent 
inhibited. 

Will  this  phenomenon  occur  if  the  fingers  moved  are  not 
symmetrical?  To  investigate  this  point  Rl  and  Z,2,  R2  and 
Zri,  Ri  and  £4  and  Li  and  R^.  were  tapped  simultaneously.1 

TABLE  IV 


Subject  A 

Subject  B 

Ri 

155 

R^ 

158 

S 

176 

3 

21 

Ri 

173 

R2 

164!    5 

174 

9 

10 

Li 

112 

L2 

127 

S 

141 

IS 

29 

Li 

145 

L2 

143 

S 

144 

2 

i 

Ri 

160 

Li 

125 

S 

148 

35 

Ri 

185 

Li 

150'    S 

164 

35 

14 

R2 

161 

L2 

129 

S 

155 

32 

26 

R2 

178 

L2 

151!    5 

162 

27 

ii 

Ri 

161 

L2 

140 

5 

132 

21 

—  8 

Ri 

181 

L2 

150;    S 

160 

IO 

R2 

157 

Li 

132 

S 

132 

25 

0 

R2 

174 

Li 

149 

S 

158 

25 

9 

Ri 

160 

1*4 

89 

S 

93 

71 

4 

Ri 

177 

L4 

133 

S 

144 

44 

ii 

R4 

107 

Li 

140 

S 

109 

33 

2 

R4 

H5 

Li 

152 

S 

150 

7 

5 

Subject  C 

Subject  D 

Ri 

169 

R2 

151 

S 

164 

18 

13 

Ri 

138 

R2 

154 

5 

150 

16 

12 

Li 

112 

L2 

lie 

S 

121 

3 

9 

Li 

139 

L2 

S 

140 

8 

9 

Ri 

185 

Li 

117 

S 

125 

68 

8 

Ri 

138 

Li 

133 

S 

5 

—  2 

R2 

I6S 

L2 

118 

S 

130 

47 

12 

R2 

155 

L2 

133 

S 

133 

22 

O 

Ri 

193 

L2 

I2C 

S 

129 

64 

4 

Ri 

135 

L2 

139 

S 

127 

4 

—8 

R2 

I67 

Li 

126 

S 

120 

41 

—  6 

R2 

152 

Li 

139 

S 

138 

13 

—  i 

Ri 

195 

L± 

98 

S 

95 

97 

—  3 

Ri 

141 

L± 

84 

S 

in 

57 

27 

R4 

Li 

119 

S 

112 

6 

—  i 

Ri 

98 

Li 

139 

S 

106 

8 

In  the  combination  Ri  1,2  both  B  and  C  and  in  R2  Li,  B  still 
show  an  increase  in  the  rate  of  the  slower  finger.  A  has  now 
dropped  below  the  single  tapping  for  Ri  Li  and  D  is  below 
for  both.  With  Ri  £4  and  R^  Li  all  the  subjects  but  C  show 
an  increase  in  the  slower  movement.  C's  simultaneous  move- 
ment is  slightly  below  that  of  the  slower  finger. 

In  order  more  readily  to  examine  and  analyze  these  results 
the  difference  between  the  tapping  rates  of  the  two  fingers 

1  It  has  not  been  thought  necessary  to  give  a  complete  table  of  these  tests.  The 
averages  were  taken  from  fewer  series  than  the  previous  ones,  but  as  the  general  re- 
lationship does  not  vary  materially  from  series  to  series  they  can  be  safely  used. 


4^0  H.  S.  LANGFELD 

has  been  placed  in  the  seventh  column  of  Table  IV.  and  the 
increase  in  the  rate  of  the  slower  finger  during  the  S  move- 
ment in  the  eighth  column.  A  minus  sign,  of  course,  indicates 
a  decrease. 

Examining  first  .5's  result  we  find  that  in  the  asymmetrical 
pair  Ri  Li  there  is  less  of  an  increase  of  the  slower  movement 
than  with  the  symmetrical  pair  Ri  Li,  an  increase  of  ten 
as  compared  to  fourteen,  but  the  pair  Ri  £4  which  is  more 
asymmetrical  than  jRi  Li  shows  a  slightly  greater  increase, 
i.  <?.,  eleven  compared  to  ten.  In  this  latter  case,  however, 
the  difference  between  the  rates  of  the  two  fingers  Ri  and  £4 
is  greater  than  between  the  former  pair  Ri  Li.  The  former 
is  raised  one  third  of  the  difference,  the  latter  only  one  fourth 
of  the  difference.  The  result  suggests  that  there  are  two 
factors  influencing  the  rapidity  of  the  simultaneous  movement, 
the  degree  of  symmetry  and  the  difference  in  the  rapidity  of 
the  two  members  of  the  pair.  These  two  factors  should  act 
in  opposite  directions;  the  difference  between  the  rate  of  the 
two  fingers  increases  as  a  rule  with  the  decrease  in  symmetry, 
and  the  greater  this  difference  in  rate  the  more  should  the 
slower  finger  be  aided  by  the  faster  in  simultaneous  tapping, 
but  the  greater  the  assymmetry  the  less  is  the  advantage  of 
simultaneous  tapping.  The  relation  of  these  two  factors  very 
likely  differs  in  individuals.  When  the  coordination  is  not 
good  asymmetry  probably  plays  an  important  role  in  slowing 
the  movement.  When  the  coordination  is  good  the  rate 
differences  have  more  effect.  Let  us  examine  the  data  further 
with  this  suggestion  in  mind.  Take  for  example  B's  Ri  Li 
and  R2  L2.  The  asymmetry  is  the  same  but  the  difference  in 
rate  of  the  R2  Li  pair  is  less  than  that  of  the  Ri  Li  and  con- 
sequently the  increase  of  the  slower  movement  is  less.  With 
Ri  £4  the  asymetry  is  increased  but  the  difference  rate  is  also, 
so  that  the  actual  increase  in  rate  remains  the  same  as  the 
other  pair.  In  the  case  of  A  with  the  same  two  pairs  it  is 
true  that  the  results  are  in  the  opposite  direction,  but  in  the 
next  pair  there  is  a  drop  in  both  symmetry  and  difference  and 
there  is  in  consequence,  a  falling  off  in  the  rate  of  simultaneous 
tapping  in  the  one  case  even  below  the  slower  of  the  pair. 


FINGER  MOVEMENTS 

In  the  most  asymmetrical  pair,  Ri  £4,  the  difference  is  very 
large  and  there  is  again  an  increase  of  the  slower  movement 
notwithstanding  the  great  asymmetry.  In  £4  Li,  a  pair  of 
like  asymmetry,  there  is  less  difference  and  less  increase. 
Turning  to  Z)'s  record,  we  find  that  although,  like  the  other 
subject,  he  showed  an  increase  when  the  two  fingers  were  of 
the  same  hand  whether  the  right  or  the  left,  as  soon  as  the 
movements  are  on  opposite  sides  there  is  often  evidence  of  an 
inhibition.  In  the  Ri  Li  pair  we  should  not  expect  much 
change  for  there  is  little  difference  between  the  rates,  but 
with  the  R2  Lz  pair,  although  the  difference  is  twenty-two 
taps  there  is  no  increase  of  the  slower  finger,  and  in  the  Ri  L^ 
pair  the  lack  of  coordination  actually  causes  an  inhibition  of 
the  slower  movement  amounting  to  eight  taps.  The  results 
for  Ri  L\  and  R^  Li  taken  in  connection  with  the  foregoing 
results  of  this  subject,  speak  strongly  for  the  assumption  of  the 
above  mentioned  opposing  factors.  The  pairs  are  the  most 
asymmetrical  but  the  differences  in  rate  are  very  large,  being 
for  one  almost  three  times  as  great  as  the  largest  previous  differ- 
ence. Examining  the  rate  for  simultaneous  tapping  we  find 
that  the  slower  movement  increases  by  twenty-seven  taps 
for  Ri  £4,  that  is,  the  facilitation  is  31  per  cent,  of  the  rate 
when  the  finger  is  moved  alone,  and  for  R\  Li  there  is  an 
increase  of  only  eight  but  the  difference  is  less,  forty-one 
compared  to  fifty-seven.  The  inhibitory  effect  of  asymmetry 
which,  judging  from  the  previous  results,  is  most  probably 
present,  has  been  more  than  overcome  by  the  facilitating 
effect  of  the  rate  difference.  This  explanation  also  fits  C's 
result  although  he  differs  in  type  from  the  other  subjects. 
It  will  be  found  when  we  come  to  the  further  test  performed 
that  C  showed  much  more  pronounced  lack  of  coordination 
of  different  muscle  groups  than  the  other  subjects.  There 
should  therefore  be  less  facilitation  and  probably  even  in- 
hibition. But  he  also  showed  the  largest  rate  difference. 
Therefore,  although  the  facilitation  is  less  than  in  the  case  of 
A  and  B,  nevertheless  it  is  present  in  some  instances.  In 
the  pair  Ri  L\  the  large  difference  of  ninety-seven  was  not 
sufficient  to  overcome  the  inhibition  of  asymmetry  and  when 


462  H.  S.  LANGFELD 

we  notice  that  with  the  much  more  symmetrical  pair  Ri  L.2 
the  large  difference  of  sixty-four  was  only  able  to  cause  a 
facilitation  of  four  taps,  and  with  R2  Li  there  was  a  difference 
of  forty-one  and  yet  a  decrease  of  six  taps,  this  result  is 
rather  to  be  expected.  The  only  figures  which  do  not  readily 
offer  themselves  to  the  explanation  here  attempted  are  those  of 
the  pair  R2  L.2.  The  symmetry  of  R2  Z,2  is  the  same  as  Ri  Li 
but  a  difference  of  forty-seven  in  the  former  pair  causes  a 
facilitation  of  twelve  taps  while  a  difference  of  sixty-eight 
in  the  latter  pair  only  causes  a  facilitation  of  eight.  It  is 
true  that  with  none  of  the  subjects  is  the  relation  of  facilitation 
to  rate  difference  constant.  This  ratio  also  varied  with  the 
different  subjects.  Two  points  might  be  mentioned  in  this 
regard.  First,  equality  in  symmetry  does  not  necessarily 
mean  the  same  amount  of  coordination  of  different  muscle 
impulses.  Thus  in  the  results  of  C,  although  Ri  Li  and  R^  L^ 
are  both  symmetrical  pairs  the  coordination  between  R2 
L.2  is  better  than  between  Ri  Li,  and  perhaps  for  that 
reason  the  smaller  rate  difference  has  a  greater  facilitating 
effect.  This  explanation  could  also  be  offered  in  regard  to 
the  similar  results  of  A.  Secondly,  although  the  change  in 
symmetry  between  any  two  pairs  is  naturally  the  same  for 
all  subjects,  yet  one  subject  will  probably  have  a  different 
change  in  coordination  in  going  from  one  pair  to  another, 
than  a  second  subject,  and  this  will  readily  explain  individual 
differences  in  the  above  mentioned  ratio.  It  should  also  be 
mentioned  that  investigations  on  other  subjects  revealed  a 
difficulty  to  synchronize,  which  retarded  the  simultaneous 

movement. 

ALTERNATING  TAPPING 

As  was  stated  above  the  alternating  tapping  was  performed 
in  the  same  series  as  the  simultaneous  and  the  figures  for  Ri 
and  R2  may  again  be  used.  A  is  the  alternation  in  which 
one  finger  ascends  while  the  other  descends  and  CA  the  com- 
plete alternation  in  which  one  finger  does  not  begin  to  move 
until  the  other  has  returned.  The  figures  express  only  the 
rate  of  one  finger,  the  number  of  actual  taps  made  being 
twice  that  number.  In  Table  V.  these  alternations  are 


FINGER  MOVEMENTS 


4*3 


expressed  in  per  cent.,  of  the  average  of  the  two  fingers  tapping 
singly.  Let  us  first  discuss  the  A  results.  If  the  fingers  were 
alternating  levers  of  a  mechanical  machine  there  would,  of 
course,  be  twice  as  much  work  done  in  the  same  time  as  one 
lever  working  alone  would  perform.  In  the  human  machine 
when  two  different  movements,  and  in  this  case  opposite 
movements,  are  carried  on  simultaneously  we  look  for  some 

TABLE  V 


Right  Hand 

Left  Hand 

A 

CA 

A 

CA 

Rl.  +  /?2 

Ri  +  R2 

Li  +  Lv 

Li  +  L* 

a 

2 

2 

2 

Subject  A  .  .  .  . 
Subject  B  
Subject  C  
Subject  D  

.81 
.83 

•37 

•73 

.27 
.24 
.16 
•25 

•  SO 
.80 

•54 
•74 

.28 
.26 

•11 

inhibition.  The  amount  of  this  inhibition  is  expressed  in 
the  per  cent.  It  will  be  seen  that  for  three  of  the  subjects 
A,  By  and  Z),  with  the  right  hand  there  is  only  a  loss  of  about 
one  quarter  of  the  speed  of  one  finger  when  working  alone. 
In  other  words  by  carrying  out  simultaneously  two  movements, 
though  opposite  in  nature,  there  is  a  gain  of  fifty  per  cent,  as 
compared  to  the  amount  of  work  done  if  only  one  movement 
was  performed  in  the  same  time.  The  other  subject,  C, 
shows  a  much  lower  figure.  It  is  only  thirty-seven  per  cent., 
which  means  that  there  is  an  actual  loss  in  work  accomplished 
by  alternating  simultaneous  movements  of  thirteen  per  cent. 
In  his  present  state  of  muscular  coordination  he  would  accom- 
plish more  with  one  finger  moving  alone  than  he  would  by 
moving  two  fingers.  Fifty  per  cent,  would  mean  that  the 
work  accomplished  by  the  two  fingers  is  the  same  as  if  one 
had  moved  alone.  The  actual  figures  make  the  above 
perhaps  clearer.  Alternating  he  only  taps  fifty-nine  times 
for  each  finger,  or  one  hundred  and  eighteen  taps  in  all,  while 
the  mean  of  the  rate  of  the  two  fingers  tapping  alone  is  160. 
The  loss  is  forty-two  taps  or  twenty-six  per  cent,  for  the  two 
fingers.  This  subject  is  the  one  referred  to  on  page  461  as 
having  poor  coordination  between  different  muscle  groups. 


464  H.  S.  LANGFELD 

The  above  figures  make  this  evident.  In  this  connection  it 
is  very  interesting  to  note  that  C's  rate  of  tapping  with  one 
one  finger  is  faster  than  any  of  the  other  subjects  with  the 
exception  of  B.  From  this  it  would  seem  that  the  inhibition 
is  a  variable  independent  of  the  rate  of  movement  of  the 
separate  muscle  groups.  This  assumption  is  strengthened 
by  the  results  of  the  left  hand.  The  separate  tapping  rates 
are  much  lower  but  the  A  rate  is  about  the  same  as  before, 
consequently  the  per  cent,  is  higher.  Subject  A  shows  this 
same  independence.  The  A  rate  for  the  left  hand  has  dropped 
relatively  much  lower  than  the  separate  rates  and  the  per  cent, 
is  consequently  lower.  In  fact  it  is  now  about  the  same  as  C's 
rate.  That  is,  his  coordination  in  the  left  hand  is  worse  than 
in  the  right.  Subjects  B  and  D  show  almost  identically  the 
same  amount  of  coordination  for  both  hands.  To  repeat, 
the  above  results  substantiate  a  fact  which  from  what  we 
already  know  is  rather  obvious,  that  the  degree  of  coordina- 
tion between  several  muscle  groups  does  not  bear  any  definite 
relation  to  the  degree  of  efficiency  of  the  separate  muscle  groups 
concerned. 

Particularly  in  regard  to  the  coordination  of  these  move- 
ments it  seems  of  interest  to  inquire  into  the  musical  training 
of  the  subjects.  A  is  proficient  with  the  violin,  B  has  played 
the  organ  since  boyhood,  C  has  just  begun  to  take  piano 
lessons,  and  D  has  played  the  piano  for  years  for  his  own 
amusement.  $'s  ratios  of  83  per  cent,  and  80  per  cent,  are 
the  highest  of  any  subjects  and  one  is  disposed  to  say  that 
this  is  due  to  greater  practice  and  that  C's  low  ratio  is  due  to 
lack  of  training.  A's  figures  are  what  one  would  expect. 
Being  a  violinist  the  fingers  of  the  left  hand  are  trained  to  a 
different  set  of  movements.  In  playing  the  fingers  are  bent 
and  one  is  held  down  while  the  other  taps.  There  would 
therefore  be  an  inhibition  when  the  fingers  were  forced  to  tap 
alternatingly.  This  would  account  for  the  50  per  cent,  which 
is  even  lower  than  that  of  the  untrained  C.  These  results, 
then,  seem  to  indicate  degrees  of  practice  but  they  are  too 
few  to  be  more  than  a  suggestion.1 

1  O.  Raif  argues  that  the  fastest  rate  required  by  any  piece  of  music  is  slower  than 
the  average  rate  of  tapping,  and  therefore  piano  practice  does  not  increase  the  rate 


FINGER  MOVEMENTS  465 

There  remain  to  be  examined  the  results  of  complete 
alternation  (CA).  Again  using  the  illustration  of  a  mechan- 
ical machine  the  one  lever  begins  to  move  after  the  other  has 
stopped.  The  work  done  in  a  given  time  is  the  same  as  if 
there  were  only  one  lever  which  moved  continuously  instead 
of  alternating  with  the  second  lever.  Each  ringer  carrying 
out  such  a  movement  should  do  fifty  per  cent,  of  that  which 
it  would  do  if  working  continuously.  Instead  it  will  be  seen 
that  all  the  subjects  with  the  exception  of  C  do  only  about 
twenty-five  per  cent,  whether  with  the  right  or  left  hand. 
C's  loss  is  again  greater  than  that  of  the  other  subjects  for  the 
right  hand.  This  difference  is  less  than  in  the  A  rate  and  with 
the  left  hand  he  shows  almost  the  same  per  cent,  of  loss  as 
they  do.  These  figures  mean  that  in  this  alternation  there  is 
a  fifty  per  cent,  loss  in  muscular  work  done.  This  amount  of 
loss  seems  to  be  relatively  the  same  for  both  the  right  and 

left  sides. 

INDEX  OF  RIGHTHANDEDNESS 

The  indices  of  righthandedness  of  the  first  and  second 
finger  in  the  performance  of  the  different  combinations  here 
investigated  are  given  in  Table  VI.  As  has  been  done  both 
by  Woodworth  and  by  Wells1  the  index  is  obtained  by  dividing 
the  rate  of  tapping  of  the  left  hand  by  that  of  the  right,  thus 
giving  the  ratio  of  the  efficiency  of  the  two  sides.  .As  has 
been  found  in  the  tapping  with  the  whole  hand  there  are  great 
individual  differences.  The  range  is  even  greater  than  that 
found  by  Wells.  It  is  significant  that  subject  C,  who  showed 
poor  coordination  in  the  more  complex  movements  has  also 
the  lowest  LijRi  index  which  means  that  he  is  also  relatively 
inferior  to  the  others  in  this  simpler  coordination  for  the  left 

but  rather  the  proper  timing  of  the  movements.  He  says:  "Nicht  in  der  Bewegung  an 
sich,  sondern  in  der  Rechtzeitigkeit  der  Bewegung,  d.  h.  in  dem  Zeitverhaltniss  von 
einer  Bewegung  zur  anderen  liegt  die  Schwierigkeit.  Diese  Rechtzeitikgeit  kann  zwei- 
fellos  nur  ein  Product  unseres  Willens  sein,  wir  haben  also  den  Ausganspunkt  fur  die 
Fingerfertigkeit  in  den  Centraltheilen  unseres  Nervensystems  zu  suchen,  etc."  ('  Ueber 
Fingerfertigkeit  beim  Clavierspiel,'  Zeitschrift  fur  PsychoL,  24,  1900,  p.  354.)  While 
upon  the  subject  of  characterization  it  is  worth  mentioning  that  B  has  the  fastest 
tapping  rate  and  D  the  slowest,  and  both  are  very  athletic,  as  was  mentioned  above, 
which  means  that  here  there  is  zero  correlation  between  strength  and  rate  of  tapping. 
1 '  Normal  Performance  in  the  Tapping  Test,'  Am.  Jour,  of  Psychol.,  19, 1908^.446. 


466 


H.  S.  LANGFELD 


hand.  The  indices  for  the  efficiency  during  the  first  and  second 
half  year's  work  have  been  given  separately  under  each 
subject,  and  we  notice  that  the  change  is  not  great.  Of  these 
indices  five  are  slightly  lower,  two  are  the  same,  and  one  higher. 
That  is,  there  is  an  indication  that  practice  has  had  somewhat 
more  effect  upon  the  right  hand  than  the  left.2  The 


m- 


TABLE  VI 


Sub- 

Li 

Lz 

(L)A 

(L)CA 

Sub- 

Li 

£2 

(L)A 

(L)CA 

ject 

Ri 

R2 

WA 

(R)CA 

ject 

fa 

J?a 

(R)A 

(R)CA 

A.  .. 

.72 

.80 

.46 

.78 

c. 

.66 

.76 

I  O3 

I  O± 

.78 

.80 

.63 

•71 

*>VT 

B... 

.83 

.87 

.82 

.92 

z>.... 

1.  00 

.8<J- 

•93 

•97 

.81 

.85 

.96 

.86+ 

dividual  characteristics,  however,  remain  unaltered,  the 
ranking  of  the  subjects  according  to  the  size  of  index  being 
the  same.  With  three  of  the  subjects  the  Li/Ri  index  is 
somewhat  lower  than  the  L^\R^  index  due  to  the  superiority 
of  the  efficiency  of  the  index  finger  of  the  right  hand.  This 
is  not  the  case  with  subject  Z),  whose  R2  is  throughout  de- 
cidedly the  most  efficient  finger.1 

In  the  A  and  CA  movements  subject  B,  who  had  the  best 
coordination,  shows  an  index  similar  to  his  index  for  simpler 
movements.  Subject  A  has  the  same  for  CA  but  as  shown 
above  his  coordinated  wth  the  A  movement  on  the  left  side 
was  poor  and  his  A  index  is  therefore  much  lower  than  his 
other  indices.  Subject  C  has  the  same  great  difficulty  with 
both  hands  and  consequently  has  practically  no  index. 
Subject  D  has  a  higher  index  for  the  CA  movements.  From 

2  Wells's  results  are  similar  to  these.  He  writes:  "Again,  in  neither  subject  does 
the  left  hand  show  an  improvement  relative  to  the  right.  In  Subject  1  the  index  of 
right-handedness  remains  practically  the  same.  In  Subject  II.  the  right  hand  may 
even  improve  more  than  the  left."  Loc.  cit.,  p.  454.  Our  subject  A  with  one  of  the 
fingers  of  his  left  hand  showed  an  improvement  relative  to  the  right-hand  finger. 
Whipple  remarks,  loc.  cit.,  p.  143,  that  "practice  affects  the  left  hand  no  more  than  the 
right;  consequently  the  index  of  right-handedness  is  unaffected  by  repetition  of  the  test." 
This  generalization  is  not  borne  out  by  all  of  the  subjects  in  this  experiment,  nor  by  all 
of  Wells's  subjects. 

1  The  subject  could  give  no  reason  for  this.  He  had  never  to  his  recollection  exer- 
cised this  finger  more  than  the  others,  and  believes  it  must  be  an  inate  characteristic. 


FINGER  MOVEMENTS  467 

these  results  we  again  see  the  low  correlation  of  these  complex 
coordinations  with  the  simpler  coordinations  of  the  single 
movement  as  was  shown  before. 

PRACTICE  EFFECT 

The  experiments  were  not  arranged  with  the  idea  of 
investigating  practice  and  fatigue,  but  it  does  not  seem  amiss 
to  discover  what  evidence  there  is  of  their  effect  under  the 
conditions  described.  An  examination  of  the  tables  I.,  II. 
and  III.  shows  as  was  to  be  expected  from  the  results  of 
previous  work  that  the  improvement  is  not  a  steady  one.  If 
curves  were  plotted  they  would  reveal  the  characteristic 
fluctuations.  As  stated,  the  maximum  rate  for  each  series  is 
in  heavy  type.  See  Tables  I.,  II.  and  III.  It  will  be  seen 
that  it  may  occur  at  almost  any  point  of  the  series,  nor  is  the 
Ri  maximum  necessarily  obtained  on  the  day  of  the  R2 
maximum  or  the  S  maximum  on  the  day  of  the  maximum  of 
either  finger  concerned,  nor  does  the  A  maximum  always 
occur  on  the  day  of  the  AC  maximum.  In  short  there  is  a 
low  correlation  as  regards  the  days  of  the  maximum  results 
for  the  different  fingers  of  the  different  movements. 

Table  VII.  has  been  arranged  to  show  the  general  change 
between  the  first  and  second  half-year's  work,  and  between 
the  first  and  second  part  of  the  first  half  year.  The  figures 
in  the  first  and  second  horizontal  columns  are  the  averages  for 
the  first  and  second  half  of  the  series  given  in  Tables  I.  and  II. 
The  third,  fourth,  and  fifth  horizontal  columns  contain  the 
result  of  the  second  half  year's  work. 

It  will  be  seen  that  .with  the  separate  tapping  of  the  fingers 
of  the  right  hand  in  the  case  of  two  of  the  subjects,  B  and  C, 
there  is  decided  evidence  of  the  effect  of  practice,  not  so  much 
with  B  in  the  difference  between  the  first  and  second  half 
year  as  in  the  difference  of  the  halves  of  the  first  half  year. 
The  other  two  subjects  do  not  show  this  difference,  in  fact  A 
in  the  first  half  year  shows  a  falling  off.  With  the  left  hand 
fingers  B  and  C  again  show  the  effect  of  practice,  but  it 
is  not  so  marked  as  with  the  right  hand.  Subject  A  shows 
a  practice  improvement  in  the  index  finger  of  the  left  hand, 


468 


H.  S.  LANGFELD 


and  subject  Z)'s  results  again  show  no  evidence  of  practice 
effect.  In  the  alternating  movements  B  shows  decided 
improvement  as  does  also  A,  while  C,  who  had  great  difficulty, 
shows  a  considerable  loss.  D  remains  about  the  same.  In 
the  complete  alternation  there  is  no  significant  changes.  The 
change  in  the  simultaneous  movement  follows  the  change  in 
the  individual  movement. 

The  most  evident  fact  in  these  results  is  the  wide  individual 
differences    which    preclude    any   general    statement.     It   is 

TABLE  VII 


Subject 

Ri 

#2 

A 

CA 

5 

Li 

L* 

A  

158 

168 

121 

4.1 

184 

•**• 

112 

127 

J 

152 
1  60 

149 
161 

133 

T 

43 

168 

125 

•*/ 
129 

160 

161 

157 

B  

169 

154 

136 

41 

168 

141 

14.3 

180 

176 

4s 

T^ 

41 

181 

TJ 

150 

*TJ 
ISI 

185 

178 

177 

181 

174 

c  

157 

143 

68 

27 

158 

112 

lie 

187 

f 

163 

59 

*5 

J 

174 

117 

J 

III 

185 

I6S 

193 

I9S 

I67 

D 

I4.O 

ICQ 

106 

14. 

IC2 

I3Q 

131 

**r 

136 

0  -7 

155 

107 

«JT 

37 

0 

I48 

Js 

133 

*  j  *• 
133 

138 

155 

141 

135 

152 

interesting  to  note,  however,  that  practice  does  affect  the 
result  in  some  cases  even  though  the  daily  amount  of  work  of 
each  finger  is  slight  and  there  is  a  week's  interval,  if  not  more, 
between  each  series.1  Another  fact  to  be  noticed  is  that  the 
practice  gain  in  the  more  complex  coordination,  as  in  the  case 
of  the  A  movement,  may  be  independent  of  the  progress  of  a 
less  complicated  movement.  In  the  case  of  subject  A  both 
^i  and  R2  show  a  loss  in  rate  in  the  second  half  of  the 
series,  J?2Js  loss  being  considerable,  and  yet  the  A  movement, 

1  The  difference  of  practice  gain  between  the  two  hands  appeared  in  the  difference 
of  indices  for  right-handedness,  p.  466. 


FINGER  MOVEMENTS 


469 


which  is  a  coordination  of  these  two,  shows  a  decided  gain. 
Subject  C  shows  a  gain  by  practice  in  Ri  and  R2,  and  a  loss 
in  the  A  movement.  Finally  the  fact  that  the  more  voluntary 
movement,  CA^  shows  practically  no  change  in  rate,  should  be 
emphasized. 

The  two  horizontal  columns  next  to  the  last  column  in 
Tables  I.  and  III.  are  arranged  to  compare  the  averages  of  the' 
two  orders  of  procedure.  The  first  one  of  these  horizontal 
columns  for  each  subject  gives  the  averages  when  a  single 
finger  movement  precedes  the  double,  simultaneous  move- 
ment, the  second  when  the  reverse  order  is  used.  In  both 
series  the  rate  for  the  R  finger  for  all  subjects  except  C  and 
one  figure  for  B  is  more  rapid  when  the  R  succeeds  than 
when  it  precedes  the  S  movement.  In  the  majority  of  cases 
the  difference  is  as  large  or  larger  than  the  m.v.  Only  in 
two  instances  is  the  rate  for  the  L  appreciably  affected 
by  the  order  and  the  results  are  of  opposite  nature.  The 
simultaneous  movement  in  three  cases  is  decidedly  more 
rapid  when  it  starts  the  series,  in  two  instances  the  difference 
is  greater  than  the  m.  v.  The  only  results,  then,  that  seem 
at  all  significant  are  those  that  show  the  R  movements  more 
rapid  when  they  succeed  the  other  movements.  The  possible 
explanation  is  that  with  this  finger  the  warming  up  effect  was 
greater  than  the  fatigue.  It  must  be  remembered  that  there 
was  a  pause  of  two  minutes  between  the  3O-second  tests 
which  could  very  well  be  sufficient  for  recovery  of  this  finger 
but  not  for  the  others.  In  the  wrist-tapping  test  Wells  used 
two  and  a  half  minute  pauses  and  his  results  show  an  increase 
in  rate  as  the  series  progressed. 

FATIGUE 

The  amount  of  fatigue  in  each  3O-second  series  is  calculated 
by  finding  the  relation  of  the  difference  in  rate  of  the  first  and 
second  15  seconds  to  the  entire  30  seconds.  These  were  found 
for  the  results  in  Tables  I.  and  III.  and  are  given  in  decimal 
form  in  table  VIII.  The  absolute  differences  are  also  given. 
For  instance,  the  first  figure  in  column  3,  i.  <?.,  .047,  was  found 
by  dividing  the  rate  of  Ri  which  is  155  into  7.3  which  is  the 


470 


E.  S.  LANGFELD 


difference  of  the  two  15-second  halves.1     The  averages  for  all 
the  subjects  are  given  in  column  10. 

Most  striking  is  the  fact  that  fatigue  is  greatest  for  the  A 
movement  and  that  there  is  no  fatigue  in  the  CA  movement.  It 
must  be  remembered  that  the  A  movement  is  the  rapid  antag- 
onistic movement,  the  CA  movement  is  very  slow  and  one  set  of 
muscles  rests  while  the  other  reacts.  This  readily  explains 

TABLE  VIII 


Subject  A 

Subject  B 

Subject  C 

Subject  D 

AT. 

Ri  . 

n 

-% 

7.5 

4 
5-5 

2-5 

5 

I 

.047 
.041 
.071 

.042 

.025 
.044 
.017 
.031 
•039 
•039 

6 

4-5 

—  1/18 
5 

5 
4 
5-5 
B 
5 
5 

•034 
.028 

•OS 
.028 

.027 
.027 

•034 
.028 

•033 
.031 

12 
8 

-4/5 

5-5 

ii 

5 
4-5 
7 

2 

6 

.071 

•053 
.07 

•033 

•059 
.043 
.036 
.042 
.017 
.046 

6 

9 
6 

-i/3 
6 

6 
6 

10 

6 

3-5 

.044 

•059 
.056 

.04 

•043 
•053 
.046 
.065 

•045 
.026 

.049 
.045 
.062 

.036 

•039 
.042 

•033 
.041 

•033 
•035 

R^ 

A 

CA 

S  

Ri.. 

Li.  .     . 

S  

R2 

L^  
S  

the  absence  of  fatigue  in  30  seconds.  This  is  not  only  true 
for  the  averages  but  with  few  exceptions  for  all  the  subjects. 
For  subject  C  the  A  movement  fatigue  is  about  the  same  as  the  Ri 
fatigue.  The  S  movement  for  Ri  and  R2  for  two  subjects  is  the 
least  fatigueable,  for  the  other  two  it  is  the  same  as  the  lowest 
index  of  the  single  finger.  In  the  S  movement  for  Ri  and 
Li  and  R2  and  Z,2  the  index  is  the  lowest  in  three  instances 
and  only  twice  is  it  higher  than  both  of  the  single  movement 
indices. 

It  may  be  said,  therefore,  that  in  general  the  simultaneous 
movement  of  two  fingers  for  30  seconds  does  not  show  more, 
and  very  often  less  fatigue  than  one  finger.  A  comparison 
of  Ri  and  R2  in  the  two  halves  of  the  table  shows  as  other 
experiments  have  before,  that  practice  has  the  tendency  to 
reduce  the  fatigue.  Only  in  one  instance  out  of  eight  is  it 

1  In  view  of  the  manner  in  which  the  results  were  recorded,  it  was  thought  better 
to  divide  the  periods  in  halves  rather  than  to  compare  the  first  five  seconds  with  the 
averages  of  the  ist,  2d,  3d,  4th,  5th  and  6th  five  second  periods  as  Wells  did.  Loc.  cit., 
p.  469.  His  index  is  higher  probably  because  the  initial  spurt  has  thus  more  influence 
on  the  result,  it  being  reduced  in  the  above  index  by  the  results  of  the  2d  and  3d  five- 
second  periods. 


FINGER  MOVEMENTS  47  * 

greater  with  practice.  As  has  frequently  been  found  the 
decrease  of  fatigue  is  the  important  factor  in  practice  gain. 
No  correlation  can  be  found  between  the  fatigability  of  the 
two  hands.  Nor  can  a  general  statement  be  made  as  to  the 
fatigue  index  of  the  right  as  compared  to  the  left  hand.  In 
three  subjects  the  relation  between  R2  and  Li  and  Ri  and  Li 
in  regard  to  fatigue  is  in  the  same  direction,  except  that  subject 
B  shows  the  same  fatigue  for  Ri  and  Li  while  R2  is  less  than 
Z,2,  but  subject  D  shows  opposite  results.  For  him  the  fatigue 
for  Li  is  greater  than  for  Ri  and  for  L.2  less  than  R2.  One  can- 
not say,  therefore,  that  if  the  Ri  finger  is  more  easily  fatigued 
than  the  Li  finger,  that  the  R2  finger  will  be  more  easily 
fatigued  than  the  L2  finger. 

VARIATIONS. 

There  is  less  variation  in  the  left-hand  movements  than 
in  those  of  the  right  hand.  This  is  what  both  Bryan1  and 
Wells2  found  for  wrist  movements.  The  small  m.  v.'s  ac- 
company the  slower  reactions  but  there  are  even  indications 
of  a  less  relative  variation  on  the  left  side.  The  simultan- 
eous movement  shows  about  the  same  variations  as  the  single 
movements.  The  CA  movement  shows  the  least  variation 
of  all  the  movements.  This  movement  being  very  slow 
(fewer  taps  per  30")  the  relative  variability  is  higher  than  with 
the  other  movements.  No  general  statement  can  be  made  in 
regard  to  the  ^-movement.  There  is  a  tendency  for  it  to 
be  relatively  larger  than  that  of  the  single  movement.  Ab- 
solutely it  is  sometimes  larger  and  sometimes  smaller. 

SUMMARY  AND  CONCLUSION 

If  the  index  and  second  finger  of  the  right  hand  are  tapped 
simultaneously  as  rapidly  as  possible  the  resulting  rate 
according  to  the  results  of  four  subjects  of  varying  degrees  of 
motor  ability,  is  faster  than  the  rate  of  the  slower  finger  and 
may  even  be  more  rapid  than  the  faster  finger  when  tapping 
singly.  There  is  doubtless  a  more  or  less  innate  coordination 

1  Loc.  cit.y  p.  163. 

2  Loc.  cit.,  p.  480. 


472  H.  S.  LANGFELD 

between  the  movements  of  the  fingers  of  the  same  hand  caused 
by  the  biologically  important  grasping  reflex.  When  the 
extensor  of  the  index  finger  is  innervated  a  tendency  for  the 
symmetrical  extensor  of  the  next  finger  to  move  is  also  ob- 
served.1 Ths  impulse  must  be  inhibited  and  it  is  probable  that 
this  inhibition  also  extended  to  the  motor  half-center  of  the 
first  finger  causing  a  loss  in  rate  of  movement.  An  inhibition 
somewhat  similar  in  nature  has  been  demonstrated  by  Sher- 
rington  in  his  experiments  on  the  stepping  reflex  when  he 
simultaneously  stimulated  two  afferents  which  are  antago- 
nistic in  their  effect.  He  says:  "Of  the  two  afferents  concur- 
rently stimulated,  that  one  which  when  stimulated  alone  causes 
flexion  of  the  joint  excites  the  flexor  half-center  and  inhibits 
the  extensor  half-center;  and  the  other  afferent,  which  when 
stimulated  alone  causes  extension  of  the  joint,  excites  the 
extensor  half-center  and  inhibits  that  of  the  flexor.  When 
both  afferents  are  stimulated  simultaneously  with  appro- 
priate intensity,  the  discharge  from  the  flexor  half-center 
represents  the  algebraic  sum  of  the  opposed  excitation  and 
inhibition  which  the  two  afferents  individually  exert  on  it, 
etc."2  In  our  experiment  it  is  the  inhibition  of  one  flexor 
half-center  which  is  communicated  to  the  other  flexor  half- 
center  and  this  inhibition  is  then  compounded  algebraically 
to  the  excitation  of  the  extensor  half-center.  When  both 
fingers  move  simultaneously  this  inhibition  is  removed. 
This  at  least  seems  to  be  a  plausible  explanation  of  the  fact 
that  the  simultaneous  movements  were  faster  than  either 
single  movement.  Whether  it  was  the  only  factor  could 
readily  be  tested  by  tapping  simultaneously  symmetrical 
fingers  on  two  hands.  It  was  found  that  under  these  con- 
ditions the  movement  of  the  slower  finger  was  facilitated, 
the  degree  varying  with  different  individuals.  The  two  fingers 
together,  however,  never  tapped  faster  than  the  faster  finger. 

1  L.  Huismans  states  "Homolaterale  M-B.  (Mit-Bewegungen)  sind  in  den  weitaus 
meisten  Fallen  auf  eine  Irradiation  des  Bewegungsimpulses  in  der  Hirnrinde  Zuruck- 
zufuhren"  ('Uber  Mitbewegungen,'  Deutsche  Zeitschrift  fur  Nervenheilkunde,  40,  1910, 

P-  233)- 

2  'Reflex  Inhibition  as  a  Factor  in  the  Coordination  of  Movement  and  Postures,' 
Quarterly  Journal  of  Experimental  Physiology,  6,  1913,  page  269. 


FINGER  MOVEMENTS  473 

Numerous  examples  are  to  be  found  in  the  literature  relative 
to  the  influence  of  the  movement  of  one  side  of  the  body  upon 
that  of  the  other.  In  the  simple  reaction  experiment  Paul 
Salow  found  that  the  reaction  time  for  simultaneous  move- 
ments of  two  hands  was  longer  for  each  hand  respectively 
than  when  they  reacted  separately.1  M.  L.  Patrizi  found  in 
his  ergograph  tests  that  in  simultaneous  action  both  hands 
did  less,  but  when  they  worked  alternately  the  right  hand 
action  reinforced  that  of  the  left  hand.  He  believes  that 
one  cannot  give  maximal  attention  to  the  two  simultaneous 
acts.2  W.  W.  Davis  found  that  in  general  the  right  hand 
tapped  more  rapidly  alone  than  in  connection  with  either  the 
other  members.  Two  of  his  subjects  were  able  to  tap  more 
rapidly  when  all  four  members  were  tapping.  He  remarks 
that  "with  a  longer  practice  the  right  hand,  in  multiple 
tapping,  would  undoubtedy  excel  in  rapidity  its  record  while 
tapping  alone."  He  also  concludes  from  his  results  that 
"there  is  a  close  connection  between  different  parts  of  the 
muscular  system  through  nervous  means.  This  connection 
is  closer  between  parts  related  in  function  or  position."  In 
this  work  Davis  was  not  interested  in  the  influence  of  the 
faster  on  the  slower  member.3  Mention  should  also  be  made 
of  the  fact  that  a  paralyzed  member  may  be  moved  by  moving 
a  healthy  member.4 

1  'Untersuchungen  zur  uni-  und  bilateralen  Reaktion.  II.  Einige  Versuche  am 
Chronographen,'  Psychol.  Stud.,  8,  1913,  pp.  506-540). 

2  Patrizi  writes:  "Les  recherches  que  j'ai  rapportees  dans  ce  memoire  nous  font 
admettre  une  uncompatibilite  d'etats  psychiques,  meme  quand  il  s'agit  de  la  coincidence, 
dans  le  meme  instant,  d'impulsions  maximales  destinees  a  des  mouvements  symetriques 
et  homogenes  et  qui  sont  habituellement  accouples."     In  regard  to  Fere's  results, 
which  indicate  that  when  the  left  hand  is  almost  fatigued  its  capacity  can  be  increased 
by  the  movement  of  the  right  hand,  he  says  that  an  increase  will  not  occur  if  the  two 
movements  are  exactly  simultaneous  ('La  simultaneite  et  la  succession  des  impulsions 
volontaires  symetriques,'  Arch.  Italiennes  des  Biol.,  19,  1893,  p.  138). 

3  'Researches  in  Cross-Education,'  Yale  Studies,  6,  1900,  pp.  6-50. 

4  See  J.  Grasset,  'L'action  motrice  bilaterale  de  chaque  hemisphere  cerebral/ 
L'annee  Psychol.,  II.,  1904,  pp.  434-445.     It  is  interesting  to  note  that  W.  P.  Lombard 
said  some  years  ago:  "Not  enough  work  has  been  done  to  admit  definite  statements 
concerning  the  strengthening  or  weakening  effect  of  the  action  of  the  one  hand  upon  the 
other.  .  .  .  The  few  observations  which  have  been  made  with  reference  to  this  question 
favor  the  idea  that  if  one  hand  acts  simultaneously  with  the  other  it  tends  to  weaken 
rather  than  strengthen  its  movements.     This  effect  is  not  a  constant  one,  however,  as 


474  H.  S.  LANGFELD 

In  searching  for  an  explanation  for  this  contralateral 
facilitation  of  the  slower  movements  by  the  faster,  the  fact 
of  sympathetic  movement  seems  the  most  significant.  Every- 
one has  had  the  experience  when  the  member  which  one 
desires  to  move  is  held  or  when  it  has  become  fatigued,  of 
moving  the  opposite  member.  In  this  regard  Ch.  Fere  re- 
marks that  the  examples  drawn  from  his  research  "indiquent 
que,  lorsqu'il  existe  un  obstacle  a  un  mouvement  volontaire 
unilateral,  Pinflux  nerveux  a  une  grande  tendance  a  prendre 
la  voie  symetrique  du  cote  oppose."  This  tendency  is  greater 
in  children,  being  later  more  or  less  suppressed.1  In  the 
simultaneous  movement  of  the  two  fingers  the  faster  finger 
must  be  held  back  to  synchronize  with  the  slower.  According 
to  the  above  if  the  one  finger  were  not  already  moving  while 
the  other  finger  was  being  held  back  from  its  full  movement 
the  sympathetic  movement  of  the  former  would  probably  be 
evident.  When  it  is  moving  at  the  same  time  as  the  finger 
which  is  being  somewhat  retarded,  its  movement  is  facili- 
tated by  the  surplus  energy  of  the  faster  finger.  There  is  also 
another  explanation  or,  perhaps,  a  second  factor  in  conjunc- 
tion with  the  above  and  that  is  the  increased  amount  of 
peripheral  stimulation,  i.  e.y  the  contact  with  the  board  and 
bar.  We  know  from  the  work  of  Sherrington,  Alexander 
Forbes,  T.  Graham  Brown,  and  others  that  the  afferent 
impulse  on  one  side  of  the  body  may  cause  a  contralateral 
reflex.  Now  the  afferent  path  on  the  ipsolateral  side  may 
be  fatigued  and  the  stimulus  on  the  contralateral  side  may 
become  more  effective.  Alexander  Forbes  says:  "The  fact 
that  central  fatigue  induced  through  one  afferent  nerve 
usually  does  not  impair  the  reflex  involving  the  same  muscles 
induced  through  another  afferent  nerve  supports  the  con- 
clusions of  Lee  and  Everingham  that  this  fatigue  does  not 
involve  the  moto-neurones,  and  accords  with  the  view  of 
Sherrington  that  its  seat  is  the  synapse."2  This  explanation 

many  exceptions  occur"  ('Alterations  in  the  Strength  which  occur  During  Fatiguing 
Voluntary  Muscular  Work/  Jour,  of  PhysioL,  14,  1893,  p.  116). 

1  L'alternance  de  1'activite  des  deux  hemispheres  cerebraux,'  UAnnee  Psychol.,  8, 
1901,  p.  148. 

1  'The  Place  of  Incidence  of  Reflex  Fatigue,'  American  Journal  of  Physiology,  31, 

1912-13,  p.  122. 


FINGER  MOVEMENTS  475 

can  also  be  applied  to  simultaneous  tapping  on  the  same  hand. 
Owing  to  the  fact,  however,  that  these  movements  were  never 
carried  on  sufficiently  long  for  any  great  fatigue  this  factor 
must  play,  if  at  all,  a  very  small  role. 

Thus  far  we  have  been  discussing  simultaneous  movements 
of  symmetrical  members.  This  facilitation  was  also  observed 
between  asymmetrical  members  but  it  was  not  so  great. 
There  can  be  little  doubt  that  the  coordination  is  less  perfect 
the  more  asymmetrical  the  members  are.  Even  the  transfer 
of  practice  is  greater  to  symmetrical  parts.1  There  is  not, 
however,  a  very  high  degree  of  correlation  between  increasing 
symmetry  and  increasing  facilitation  with  all  the  subjects. 
In  order  to  explain  the  results  an  antagonistic  factor  has  been 
suggested,  i.  e.,  that,  ceteris  paribus,  the  greater  the  difference 
within  limits  between  the  rates  of  the  two  fingers  the  greater 
the  facilitation  of  the  slower.  This  difference  increases  with 
the  asymmetry  and  at  times  causes  an  asymmetrical  pair 
to  show  greater  facilitation  than  a  more  symmetrical  pair. 
An  explanation  which  includes  two  opposing  factors  can  ex- 
plain anything  and  should  not  be  used  without  strong  proof. 
There  are,  in  this  series  of  experiments,  instances  where  the 
degree  of  symmetry  is  a  constant  and  we  see  here  the  effect 
of  difference  in  rate  in  the  direction  just  mentioned.  We 
have  also  cases  of  similar  degrees  of  difference  in  rate  and 
here  the  effect  of  symmetry  can  be  seen.  The  results  are 
not  sufficiently  consistent  to  be  conclusive.  They  are,  how- 
ever, suggestive  and  the  explanation  founded  upon  them 
must  necessarily  also  bear  that  adjective. 

2.  An  examination  was  also  made  of  the  simultaneous 
movement  of  the  index  and  first  finger  of  the  right  and  left 
hand  when  these  movements  were  in  opposite  directions,  a 
combination  of  movements  similar  to  the  stepping  reflex  and 
spoken  of  in  this  paper  as  alternating  movements.  Here 
there  is  double  reciprocal  innovation  according  to  Sherrington. 
The  four  subjects  were  divided  into  two  groups  in  respect  to 
the  amount  of  coordination.  With  three  of  the  subjects  each 
finger  was  able  to  do  about  three  quarters  as  much  in  this 

1  See  W.  W.  Davis,  loc.  cit.,  page  49. 


476  H.  S.  LANGFELD 

combination  as  when  tapping  alone,  except  for  one  of  the 
subjects  with  the  left  hand.  The  loss  for  each  finger  due  to 
this  combination  of  impulses  was  only  25  per  cent.,  so  that 
in  the  same  time  the  pair  was  able  to  do  one  and  a  half  times 
as  much  as  a  single  finger.  The  fourth  subject  showed  a 
much  poorer  state  of  coordination.  Two  of  the  three  subjects 
with  good  coordination  were  piano  players  and  the  other  who 
had  a  low  efficiency  with  the  left  hand  had  his  fingers  of  that 
hand  trained  for  another  system  of  coordination,  for  violin 
practice.  Judging,  however,  from  the  great  differences  be- 


tween these  subjects  and  from  observations  on  others,  it 
seems  probable  that  this  test  shows  some  fundamental  dif- 
ferences in  motor  coordination.  It  would  appear  profitable 
to  gather  further  data  with  special  reference  to  the  effect  of 
practice,  the  tests  here  described  being  too  few  to  draw  any 
conclusion  from  them  on  this  point.1 

Another  fact  which  appears  clearly  in  the  results  is  that 
the  amount  of  coordination  between  the  two  reflexes  does  not 
run  parallel  with  the  development  of  these  reflexes.  The 
subject  who  has  the  worst  coordination  has  one  of  the  highest 

1  Sherrington,  in  speaking  of  grace  in  walking,  says  that  "the  proper  execution  of 
the  act  ensures  a  moment  of  complete  rest  to  each  of  the  opposed  motor  centers  en- 
gaged." Loc.  cit.,  p.  271.  T.  Graham  Brown  found  very  decided  differences  in  the 
reflexes  of  the  cat "...  these  individual  variations  are  probably  due  in  great  part 
to  more  fundamental  differences  in  the  constitution  of  the  nervous  centers.  Some  cats 
are  'walkers.'  They  exhibit  in  a  marked  degree  the  phenomena  of  'narcosis  progres- 
sion.' Other  cats  are  'scratchers.'  In  them  the  scratch-reflex  is  peculiarly  excitable" 
('Studies  in  the  Physiology  of  the  Nervous  System,  XIV.  Immediate  and  Suc- 
cessive Effects  of  Compound  Stimulation  in  Spinal  Preparations,'  Quarterly  Journal  of 
Experimental  Physiology,  7,  1914,  p.  200). 


FINGER  MOVEMENTS  477 

rates  in  single  tapping.  He  is  a  subject  with  little  piano 
practice,  so  that  this  ability  in  single  tapping  substantiates 
Raif's  assumptipn  (vide  supra,  p.  464)  that  piano  players  do 
not  show  any  special  ability  in  rate  of  tapping. 

3.  The  term  complete  alternation  has  been  applied  here 
to  successive  movements  of  the  two  fingers;  one  finger  com- 
pletes both  the  extensor  and  flexor  movements  before  the 
other  begins.     With  all  the  subjects  and  with  both  right  and 
left  hand  the  two  fingers  in  this  combination  tap  only  one 
quarter  the  amount  that  they  do  in  the  same  time  in  tapping 
continuously  and  alone.     The  loss  in  this  form  of  alternating 
movement  is  about  50  per  cent.     This  combination  is  a  system 
of  successive  reflexes.     The  loss  in  efficiency  is  probably  in 
great  part  due  to  the  necessary  inhibition  of  the  previous 
reflex.     As  Sherrington  says  ".  .  .  there  will  persist  during 
the  new  reflex  activities  belonging  to  the  old  with,  in  result, 
confusion  of  the  two.     Rarely,  indeed,  can  it  happen  normally 
that  the  reflex  machinery  in  executing  a  train  of  different 
reflexes  is  actuated  by  a  train  of  different  stimuli,  each  one 
of  which  abruptly  ceases  just  as  the  next  one  begins."1     And 
further:   "For   orderly   and   unconfused    sequence   of   reflex 
acts — also  of  willed  acts — central  inhibition  is  a  necessary 
element  of  coordination  in  the  transition  from  one  muscular 
act  to  another."2     Another  reason  for  the  loss  is  that  in  the 
single  tapping  movement  inhibition  of  one  of  the  antagonistic 
movements  increases  the  tendency  for  that  reflex  to  discharge, 
causing  what  might  be  termed  a  rebound.     If,  however,  the 
finger  must  rest  after  the  completion  of  each  flexor  movement 
until  the  other  finger  has  completed  its  movement,  most  of 
this  post-inhibitory  effect  is  lost.3 

4.  Even  with  an  interval  of  one  week  between  the  tests  a 
practice  gain  in  most  of  the  movements  is  noticeable.     An 
exception  must  be  made  with  the  most  voluntary  movement, 
namely,  the  complete  alternation.     The  subject  who  had  the 
worst  coordination  in  the  alternating  movement  even  showed 
a  loss.     The  practice  effect  in  the  alternating  movement  does 

1  Loc.  cit.,  p.  275. 

2  Loc.  cit.,  p.  276. 

3  See  Sherrington,  loc.  cit.,  p.  278. 


478  H.  S.  LANGFELD 

not  run  parallel  to  the  practice  effect  of  the  fingers  tapping 
separately.  A  gain  in  the  former  may  be  accompanied  by  a 
loss  in  the  latter.  Practice  in  the  simultaneous  movement, 
on  the  other  hand,  does  follow  that  of  each  finger  when  working 
separately.  There  is  some  evidence  that  practice  affects  the 
right  hand  more  than  the  left. 

5.  Fatigue  is  noticeable  for  all  the  movements  except  the 
complete    alternation.1     It    is    greatest    for    the    alternating 
movement  and  generally  least  for  the  simultaneous  move- 
ment.    That  is,  during  thirty  seconds  there  is  less  fatigue  when 
two  fingers  are  working  simultaneously  than  when  one  is 
working  alone. 

6.  The  index  of  righthandedness  is  not  necessarily  the 
same  for  all  the  movements,  nor  is  it  always  the  same  between 
the  different  pairs  of  symmetrical  fingers. 

7.  The  variations  in  tapping  rate  are  less  for  the  left  hand. 

1  Wells  says:  "To  sum  up,  the  maximum  rate  of  repeated  voluntary  movements  is  a 
function  that  practically  every  investigator  working  with  sufficiently  accurate  methods 
has  found  to  be  subject  to  fatigue  effects,  though  the  degree  of  this  subjection  has 
differed  considerably"  ('A  Neglected  Measure  of  Fatigue,'  Am.  Jour,  of  PsychoL,  19, 
1908,  pp.  3S2-3-) 


RETINAL  FACTORS  IN  VISUAL  AFTER-MOVEMENT 

BY  WALTER  S.  HUNTER 

The  University  of  Texas 

The  present  paper  is  a  continuation  of  a  previous  study 
made  by  myself  on  the  after-effects  of  visual  motion.1  On 
pages  255-257  of  that  article,  comments  are  to  be  found 
bearing  upon  retinal  factors  effective  in  the  production  of  the 
illusory  motion  which  occurs  after  gazing  for  some  time  at  a 
series  of  moving  bands.  Again  on  pages  275  and  276  an 
experiment  is  described  in  which  a  moving  area  was  used  of  a 
size  sufficient  to  cover  most  or  all  of  the  visual  field.  In  this 
test  an  after-movement  was  observed  which  went  in  the 
same  direction  as  the  real  or  stimulus  movement.  Ordinarily 
the  after-effects  seen  are  secured  with  small  stimulus  areas 
and  move  in  a  direction  contrary  to  the  real  movement.  In 
the  earlier  study,  it  was  held  that  the  normal  after-effect  was 
a  result  of  some  or  all  of  the  following  factors:  eye-muscle 
strain,  association  factors  and  retinal  processes  which  were 
probably  fading  after-images.  The  present  work  is  primarily 
concerned  with  a  determination  of  the  nature  of  the  effective 
retinal  factors.  The  conclusion  reached  is  that  this  factor 
is  a  streaming  phenomenon  which  moves  through  external 
space  in  a  direction  opposite  to  that  taken  by  the  stimulus 
area.  The  evidence  for  this  is  necessarily  of  an  introspective 
and  theoretical  nature. 

The  data  presented  were  obtained  largely  from  three 
subjects,  two  of  whom  had  served  in  the  earlier  tests.  A 
number  of  observations  were  made  on  untrained  subjects. 
The  apparatus  used  was  the  large  striped  curtain  (six  feet 
long  by  four  feet  high)  described  in  the  earlier  paper.  This 
curtain  could  be  made  to  move  either  up  or  down.  A  small 
square  of  white  paper  was  held  close  in  front  of  the  curtain 
by  a  thread  and  served  as  a  fixation  point.  A  number  of 

1  Hunter,  Walter  S.  'The  After-effect  of  Visual  Motion,'  PSYCH.  REV.,  Vol.  21, 
pp.  245-277,  1914. 

479 


480  W.  S.  HUNTER 

newspapers  were  tacked  on  the  wall  above  the  curtain  to 
serve  as  a  projection  field  for  the  after-effects.  Other  fields 
will  be  mentioned  later.  Tests  were  also  made  with  rotating 
black  spirals  and  with  a  striped  Scripture  drum. 

EXPERIMENTAL  DATA 

The  immediate  problem  from  which  the  present  tests 
took  rise  was  that  of  the  occurrence  of  an  after-movement 
(abbreviated  as  a.-m.)  in  the  same  direction  (an  s.-a.-m.) 
as  the  stimulus  movement.  It  will  probably  conduce  to 
clarity,  if  the  observed  facts  are  grouped  accordingly  as  this 
type  of  after-movement  is  or  is  not  seen.  The  facts  concern- 
ing streaming  can  then  be  presented. 

Observations  on  S.-a.-m. — If  an  observer  is  seated  about 
one  meter  from  a  moving  curtain  of  the  type  used  here  and 
fixates  a  point  in  front  of  the  curtain  for  twenty  seconds, 
upon  turning  his  eyes  to  a  series  of  newspapers  tacked  upon  the 
wall  above  the  curtain,  he  will  usually  see  the  following  phe- 
nomenon: the  fixation  point  of  the  projection  field  and  prob- 
ably about  one  or  two  square  feet  of  the  immediately  adjacent 
paper  will  be  seen  to  move  in  the  same  direction  as  the  real  or 
stimulus  movement.  This  movement  is  most  rapid  during 
the  first  second  and  is  always  a  drifting  bodily  movement  of 
the  projection  field.  It  is  identical  in  quality  or  kind  with 
the  usual  after-movement  seen  when  a  small  stimulus  area 
(parallel  stripes  on  the  Scripture  drum  or  the  Archimedian 
spiral)  is  involved  and  when  the  projection  field  is  the  stopped 
stimulus  area.  The  difference  between  the  two  phenomena 
is  one  of  direction  only. 

I  have  never  secured  an  s.-a.-m.  using  the  stopped  curtain 
as  a  projection  field.  (The  same  is  true  for  spirals  and  for 
striped  fields  of  small  extent.)  It  is  all  but  impossible  to 
secure  it  if  the  observer  sits  within  eight  inches  of  the  moving 
curtain  even  though  he  projects  the  after-effect  above  the 
curtain  as  before.  When  the  observer  sits  some  two  and  a 
half  meters  from  the  moving  curtain,  he  can  secure  the 
s.-a.-m.;  but  in  the  tests  reported  here,  it  has  not  been  so 
easy  as  from  the  distance  of  one  meter. 


VISUAL  AFTER-MOVEMENTS  4Sl 

The  following  test  has  also  been  made.  A  white  card- 
board ii  in.  X  14  in.  with  an  aperture  4  in.  X  7J  in.  was 
placed  in  front  of  the  moving  curtain.  An  observer  seated 
at  from  one  to  three  meters  fixated  a  point  on  the  edge 
of  the  aperture  for  twenty  seconds  and  then  fixated  a  dot 
on  the  papers  above  the  curtain.  A  stationary  black  negative 
after-image  of  the  cardboard  was  seen.  In  this  a.-i.,  there 
was  a  rushing  movement  either  upward  or  downward  in  the 
same  direction  as  the  real  or  stimulus  movement.  Outside 
the  black  a.-i.  and  in  the  area  corresponding  to  the  aperture 
of  the  card,  a  movement  is  usually  to  be  seen  which  goes  in  a 
direction  opposite  to  the  real  movement.  (This  we  shall  term 
an  op.-a.-m.)  Some  observers  reported  the  whole  projection 
area  to  be  involved  in  an  s.-a.-m.  When  the  after-effect  was 
projected  upon  either  a  black  or  a  white  cardboard,  no  move- 
ment was  seen  in  the  negative  after-image  of  the  cardboard 
which  had  been  in  front  of  the  curtain. 

Observations  on  Op.-a.-m. — An  after-movement  in  the 
opposite  direction  to  that  of  the  real  movement  is  the  usual 
and  "normal"  after-effect  save  under  the  circumstances  just 
described.  When  the  moving  area  of  large  extent  is  used  and 
the  after-effect  is  projected  upon  newspapers  on  the  wall 
above  the  curtain,  an  op.-a.-m.  is  seen  particularly  below 
and  to  the  sides  of  the  fixation  point.  Simultaneously  the 
s.-a.-m.  described  above  is  seen  around  the  fixation  point. 
At  times  the  op.-a.-m.  appears  later  than  the  s.-a.-m.  Some 
observers  see  a  drifting  op.-a.-m.  around  and  over  the  fixation 
point  also.  In  this  case  the  movement  seems  to  be  between 
the  observer  and  the  paper.  These  central  and  peripheral 
op.-a.-ms.  are  nearly  always  described  as  a  film  moving  over 
the  projection  field  and  not  as  a  movement  of  the  field  itself.1 
It  is  a  radically  different  type  of  movement  from  the  s.-a.-m. 
seen  about  the  fixation  point.  The  op.-a.-m.  is  a  film 
which  is  either  described  as  a  series  of  shadows  or  as  a  'rain- 
fall' or  'sleet'  or  'dust  film.'  Frequently  this  film  will  drag 
the  projection  field  along  with  it;  but  even  in  this  case  there  is 
no  drifting  bodily  movement  as  is  seen  in  the  s.-a.-m. 

1  See  Hunter,  op.  cit.,  pp.  247-8  for  results  of  earlier  tests. 


482  w.  S.  HUNTER 

If  the  projection  field  is  the  stopped  curtain,  an  op.-a.-m. 
is  seen  which  is  a  slow  drifting  movement  of  the  field  itself. 
A  film  has  never  been  seen  by  my  observers  under  these  con- 
ditions in  the  present  tests.  This  is  also  true  when  stimulus 
areas  of  small  extent  are  used,  whether  they  are  spirals  or 
systems  of  parallel  lines.  In  the  earlier  tests  just  referred  to  in 
the  footnote,  such  a  film  was  suggested  by  the  observers. 
The  absence  of  this  in  the  present  tests  is  probably  due  to 
the  fact  that  the  subjects  were  mainly  familiar  with  intense 
films. 

Observation  on  Streaming. — It  will  be  well  to  preface  these 
observations  with  a  few  historical  comments.  Our  interest 
lies  chiefly  in  the  observations  of  Pierce,1  Szily2  and  Ferree3 
who  wrote  in  that  chronological  order.  The  present  writer 
does  not  care  to  examine  any  claims  as  to  originality.  It  is 
quite  probable  to  his  mind  that  the  phenomenon  here  under 
consideration  has  long  been  known.  Schilder,4  e.  g.,  quotes 
from  Purkinje's  'Beobachtungen  und  Versuche'  passages  on 
the  streaming  phenomenon  that  parallel  Szily's.  Ferree 
accepts  Pierce's  explanation  as  a  basis  for  distinction  between 
their  respective  observations. 

Pierce's  observations  were  made  with  a  stationary  black 
and  white  striped  area.  The  projection  field  was  a  plain 
black  ground  of  cloth  or  card.  After  some  twenty  seconds' 
fixation,  upon  turning  to  the  projection  field,  "The  appearance 
is  that  of  a  thin  cloud  of  fine  white  dust  moving  across  the  field 
of  vision"  The  direction  of  moving  is  always  perpendicular 
to  the  striped  lines.  The  same  observations  were  verified 
with  concentric  circles.  Again,  "if  the  usual  field  of  fixation 
be  divided  by  a  vertical  strip  of  some  uniform  color,  no 'drift ' 
will  be  seen  in  that  portion  of  the  field  corresponding  to  the 
strip."  In  explanation  Pierce  says  "it  seems  probable  on  the 
whole  that  the  ultimate  explanation  of  this  as  of  all  after- 

1  Pierce,  A.  H.,  'Studies  in  Space  Perception,'  pp.  331-8,  N.  Y.,  1901. 

2  Szily,  A.  v.,  'Bewegungsnachbild  und  Bewegungskontrast,'  Ztsch.  f.  Psych,  u. 
Physiol.  d.  Sinn.,  1905,  Bd.  38,  S.  124. 

3  Ferree,  C.  E.,  'The  Streaming  Phenomenon,'  Amer.  Jr.  Psych.,  1908,  Vol.  19. 

4  Schilder,  Paul,  'Uber  auto-kinetische  Empfindungen,'  Arch.  f.  ges.  Psych.,  1912, 
Bd.  25,  S. 


FISUAL  AFTER-MOVEMENTS  483 

images  of  motion,  will  be  somehow  formulated  in  terms  of 
impulses  to  movement  aroused  by  the  particular  stimulation 
that  precedes.  Perhaps  the  experiments  here  recorded  may 
contribute  their  mite  towards  this  final  explanation,  if  that 


ever  comes." 


Szily's  essential  statement  is  made  in  connection  with  his 
discussion  of  the  s.-a.-m.  and  is  as  follows:  "Die  hier  geschild- 
erten  Nebenerscheinung  begleitet,  die  dem  minder  unsich- 
tigen  Beobachter  allerdings  erst  dann  auffallt,  wenn  sie  unter 
gewissen  Versuchsbedingungen  in  erhohtem  Masse  zur  Gel- 
tung  gelant.  Ich  selbst  sehe  unter  alien  umstanden  in  der 
Peripherie  das  Regelrechte  [op.-a.-m.]  Bewegungsnachbild, 
zumeist  in  der  Hiille  eines  strahligen  Nebels,  in  entgegengest- 
zter  Richtung  ablaufen.  Bedient  man  sich  eines  noch 
dichteren  Streifenmusters,  verlangert  man  die  Dauer  des 
objektiven  Eindruckes,  setzt  man  die  Beleuchtung  des  Pro- 
jektionsgrundes  herab,  so  verbreitet  sich  diese  Zone  des  regel- 
rechten  Bewegungsnachbildes  mit  gleichzeitig  erhohter  In- 
tensitat  immer  mehr  zentrumwarts,  so  dass  sie  selbst  dem 
Ungeiibten  auffallen  muss.  An  den  Konturen  im  Bereich 
des  direkten  Sehens  aber,  solange  sie  als  wahrgenommen 
werden,  vollzeiht  sich  auch  dann  noch  stets  die  paradoxe 
[s.-a.-m.]  Scheinbewegung." 

From  Ferree  we  may  take  the  following:  "When  one  sits 
with  lightly  closed  lids,  which  must  be  kept  from  quivering, 
before  a  bright  diffuse  light  such  as  that  of  a  partly  clouded 
sky,  and  looks  deep  into  the  field  of  vision  thus  presented, 
beyond  the  background  as  usually  observed,  one  sees  about 
the  point  of  regard,  after  the  field  of  vision  has  steadied,  slowly 
moving  swirls.  These  swirls  have  the  appearance  of  streams 
of  granules1  moving  in  broad  curves  now  this  way,  now  that, 
seemingly  without  order,  unless  a  noticeable  eye-movement 
occurs,  or  is  made  voluntarily,  when  the  direction  of  streaming 
changes  to  that  of  the  eye-movement."  Ferree  is  inclined  to 
identify  the  phenomenon  with  a  diffusion  of  lymph  over  the 
retina.  Aside  from  the  above  general  description,  our  interest 
centers  in  the  drawings  which  his  subjects  made.  These 

1  Italics  mine. 


484  W.  S.  HUNTER 

represent  the  qualitative  character  of  the  phenomenon  and  are 
identical  in  everything  save  direction  with  those  made  by  my 
subjects  and  represented  in  Fig.  I. 

The  quality  of  the  streaming  observed  by  the  subjects  of 
the  present  tests  was  either  of  two  kinds:  (i)  'a  shadow-like 
succession  of  clouds'  of  rather  medium  velocity;  or  (2)  a 
'sleeting,'  ' snow-fall'  or  'dust  streaks'  which  went  usually  at 
a  high  velocity.  In  any  case,  this  streaming  is  always  in  a 
direction  opposite  to  that  of  the  real  or  stimulus  movement. 
Neither  type  appeared  in  these  tests  when  the  projection 
field  was  the  stopped  stimulus  area.  The  first  type  has  never 
appeared  when  the  projection  field  is  a  plain  black  or  white 
cardboard.  It  has  been  observed  in  the  periphery  where  the 
after-effects  have  been  projected  upon  the  paper  above  the 
large  curtain,  and  all  over  the  visual  field  when  the  after- 
effect has  been  projected  upon  floors  and  upon  plain  gray 
walls. 

The  greater  theoretical  significance  attaches  to  the  'sleet' 
film.  This  will  appear  as  the  discussion  advances.  I  have 
assumed  that  the  best  method  of  detecting  what  takes  place 
in  or  on  the  retina  is  to  project  the  phenomena  upon  black  or 
white  surfaces  (cardboard,  shadows  or  the  black  of  the  retinal 
field).  Under  these  conditions  the  phenomena  appear  un- 
modified by  variations  of  the  external  world. 

A  'dust'  or  'sleet'  film — which  is  best  represented  by  A 
in  Fig.  I — is  always  seen  if  the  after-effect  of  the  moving 
curtain  is  projected  upon  plain  surfaces  as  just  described. 
In  these  cases  it  is  pure,  i.  e.,  unmixed  with  the  first  type. 
Pierce's  test  was  carried  out  with  the  present  subjects.  The 
stimulus  areas  were  the  large  striped  cloth,  the  striped 
Scripture  drum  and  a  black  spiral  on  a  white  disc.  In  each 
case  after  a  fixation  of  twenty  seconds,  the  observer  turned 
his  eyes  to  a  black  or  white  ground  and  described  the  phe- 
nomena seen.  Drawings  of  the  after-effects  were  requested. 
When  the  stimulus  area  was  one  of  parallel  stripes,  the  after- 
effect was  a  'dust  film'  as  described  by  Pierce.  It  differed 
from  that  secured  with  a  moving  stimulus  area  only  in  its 
fainter  intensity  and  in  its  less  certain  direction.  By  the  last 


VISUAL  AFTER-MOVEMENTS 


485 


phrase,  I  mean  this:  the  Pierce  dust  film  was  perpendicular 
to  the  lines,  but  the  film  could  be  interpreted  as  moving  either 
up  or  down.  With  the  dust  film  produced  by  a  moving  stimu- 
lus area,  there  was  no  doubt  but  that  the  film  moved  in  a 
direction  opposite  to  that  of  the  stimulus  area.  The  drawing 
B  in  Fig.  I  represents  the  phenomenon  seen  on  a  plain  card 
after  having  fixated  either  a  stationary  or  a  rotating  spiral  for 
twenty  seconds.  The  difference  just  described  for  parallel 


FIG.  i.  Patterns  of  Streaming  Observed  in  the  Present  Tests.  A.  Seen  with  either 
a  moving  or  stationary  area  of  parallel  stripes  when  the  projection  field  is  a  plain 
surface.  B.  Seen  with  either  a  moving  or  a  stationary  spiral  when  the  projection  field 
is  a  plain  surface. 

lines  is  the  only  one  that  holds  here  also.  In  each  case  the 
film  has  appeared  before  the  negative  after-image  of  the 
stimulus  area.1 

Earlier  in  this  paper,  tests  were  described  where  a  white 
cardboard  with  an  aperture  was  placed  in  front  of  the  large 
moving  curtain.  In  order  to  analyze  the  nature  of  the  retinal 
factors  producing  the  peculiar  after-effects  already  described, 
the  phenomenon  was  projected  upon  a  black  card.  In  the 
black  negative  after-image  of  the  white  card  (where  the 
s.-a.-m.  had  been  under  other  conditions),  there  was  no 
movement;  but  in  the  remainder  of  the  card  which  cor- 
responded to  a  stimulated  retinal  area,  the  dust  film  was  seen 
(moving  of  course  in  a  direction  opposed  to  that  of  the  stimulus 
movement).  There  can  be  little  doubt,  then,  but  that  the 

1  See  Hunter,  op.  cit.,  p.  258. 


W.  S.  HUNTER 

s.-a.-m.  seen  in  the  black  after-image  when  this  was  projected 
upon  the  newspapers  was  due  to  association  factors.  The 
movement  of  the  film  produced  the  impression  of  a  movement 
of  the  objects  within  the  after-image  in  an  opposite  direction. 
Szily1  describes  a  similar  experiment  under  the  caption  'Kon- 
trast  im  Bewegungsnachbilde.'  I  am  uncertain  how  he  would 
explain  it.  However  other  cases  of  'contrast'  are  accounted 
for  on  the  basis  of  a  higher  threshold  for  the  perception  of 
movement  in  central  than  in  peripheral  vision.  This,  I 
think,  in  all  of  the  cases  described,  is  a  needless  hypothesis. 
The  author  has  repeated  some  of  Ferree's  tests  upon 
himself  and  one  of  his  subjects.  It  has  been  possible  to 
confirm  the  existence  of  a  normal  streaming  activity  in  the 
eye.  This  when  represented  by  drawing  is  exactly  similar 
to  the  pictures  of  dust  films  found  in  the  present  experiments 
upon  stationary  and  moving  striped  areas. 

THEORETICAL  CONSIDERATIONS 

To  keep  theory  close  to  observed  fact,  it  seems  to  the 
present  writer  that  the  choice  of  explanatory  retinal  processes 
lies  between  a  "streaming  phenomenon"  and  fading  after- 
images. The  latter  is  the  more  conventional  and  therefore 
the  more  apt  to  be  favored.  The  evidence  in  its  favor, 
however,  is  purely  hypothetical  and  non-observational. 
Hence  as  an  hypothesis  it  may  well  be  faulty.  What  is 
actually  seen  when  the  eyes  are  either  closed  or  turned  toward 
a  uniform  field  is  a  dust  like  film  in  constant  movement.  To 
pass  from  Ferree's  streaming  to  Pierce's  streaming,  it  is 
necessary  to  assume:  (i)  that  the  after-image  effects  of  the 
striped  field  make  the  dust  film  more  vivid;  and  (2)  that  in 
some  manner  the  striped  field  gives  definite  direction  to  the 
streaming.  I  can  offer  no  solution  for  the  last  statement, 
although  it  is  by  no  means  absurd  and  impossible.  Con- 
cerning the  first  assumption,  there  can  be  no  difficulty  for 
experiment  shows  that  the  film  can  be  more  readily  seen  upon 
certain  backgrounds  than  upon  others.  This  will  also  account 
for  the  fact  that  the  after-effect  is  largely  confined  to  (i.  e., 

1  Szily,  op.  cit.,  S.  126. 


VISUAL  AFTER-MOVEMENTS 


487 


visible  on)  an  area  corresponding  to  that  stimulated  by  the 
real  movement. 

Let  us  examine  each  proposed  retinal  factor  with  the  aid 
of  Fig.  2.  Of  the  phenomena  described  above,  it  is  necessary 
to  bear  in  mind  particularly  the  s.-a.-m.  about  the  fixation 
point  and  the  dust-like  film  which  is  seen  to  pass  over  the 
projection  field  in  a  direction  opposite  to  that  taken  by  the 
stimulus  area.  Our  discussion  will  be  further  aided  by  a 
quotation  from  Wundt  giving  the  conventional  statement  of 
the  after-image  theory.  "Indem  ein  schwaches  Nachbild 
der  gesehenen  Bewegung  im  Auge  zuruckbleibt,  scheint  ein 
fixiertes  Objekt  infolge  der  Relativitat  der  Bewegungsvor- 
stellung  in  entgegengesetzten  Sinne  bewegt  zu  sein.  Das 
Nachbild,  in  der  Regel  zu  Schwach  um  selbst  gesehen  zu 
werden,  geniigt  doch  um  auf  das  Objekt  die  zu  seiner  eigenen 
entgegengesetzte  Richtung  zu  iibertragen."1 

In  Fig.  2,  0  represents  the  curtain  moving  up.     i.  is  its 


FIG.  2.    Relations  between  External  Movements  and  Retinal  Processes. 

image  on  the  retina  where  the  movement  passes  down, 
a.-i.  stands  for  the  fading  after-images  which  move  in  the 
same  direction  as  i.  and  not  up  with  the  curtain,  0.  Let  us 
assume  that  twenty  seconds  have  passed  and  the  striped 
curtain  or  drum  is  stopped.  Upon  whatever  objects  the  eye 
is  turned  the  stationary  images  of  these  objects  will  be  cast 
upon  the  area  i.  over  which  the  fading  after-images  (a.-i.) 
are  passing  downward.  We  have  two  possibilities  now:  (i) 
The  fading  after-images  do  not  enter  consciousness.  In  this 
case  a.-i.  passing  down  over  i.  gives  the  impression  of  i. 
moving  up,  i.  e.,  is  the  same  as  though  a.-i.  were  stationary 

1  'Physiol.  Psych./  Bd.  2,  S.  622,  6.  Aufl.,  Leipzig,  1910. 


488  W.  S.  HUNTER 

and  i.  were  moving  up.  i.  projected,  then,  into  the  external 
world  would  be  seen  as  0  in  movement  downward.  (Here  I 
assume  that  a  sub-liminal  retinal  process  is  not  projected  into 
space.  If  it  were  it  would  be  discussed  as  though  the  a.-i. 
came  into  consciousness  and  hence  would.be  treated  under 
(2)  below.)  The  present  case  can  explain  an  s.-a.-m.  about 
the  fixation  point  by  claiming  that  for  some  reason  the  move- 
ment of  a.-i.  on  the  retina  is,  relatively,  non-effective  in  central 
vision.  Szily  does  this  by  appealing  to  the  high  central 
threshold  for  the  perception  of  movement.  The  truth  in 
this  point  lies  only  in  the  observable  fact  that  the  direction 
of  apparent  movement  differs  in  the  periphery  and  in  the 
center.  The  explanation  of  this  lies  in  the  fact  that  the  clear 
bold  contours  in  central  vision  dominate  over  the  moving 
process  as  compared  with  the  peripheral  contours.  When  the 
after-effect  is  projected  upon  plain  cardboard  the  dust  film 
is  seen  all  over  the  field.  The  effectiveness  of  contours  in 
inhibiting  the  perception  of  after-movements  is  shown  by 
Szily,1  and  is  continually  verified  in  tests  on  after-movements. 
The  validity  of  that  investigator's  threshold  hypothesis  is 
further  impugned  in  the  following  case.  (2)  //  the  fading 
after-images  do  enter  consciousness,  they  do  so  as  projected 
into  external  space,  a.-i.  is  then  seen  as  F'  moving  up.  0 
seen  through  this  appears  to  move  down.  The  damning 
fact,  however,  is  that  the  film  or  'sleet'  is  actually  seen  not 
as  F1  but  as  F  and  moves  down.  It  cannot  therefore  be  the 
projection  into  space  of  fading  after-images.  The  retinal 
equivalent  of  the  film  which  is  seen  to  move  down  over  the 
external  objects  must  be  the  passage  of  a  stimulation  upward. 
However  before  ruling  fading  after-images  out  entirely,  it  is 
well  to  consider  the  following  possibility:  May  it  not  be  that 
a.-i.  passing  down  over  i.  is  the  equivalent  of  a  wavering  or 
filmy  passing  of  i.  upwards  on  the  retina?  This  when  pro- 
jected would  give  F.  Such  an  hypothesis  appears  fairly 
plausible  when  F  is  projected  upon  print  or  other  equally 
diversified  objects.  In  that  case  a  cloudy  or  wavy  film  is 
often  seen  to  pass  down.  The  plausibility  of  the  theory, 
1  Op.  dt.,  S.  1 10. 


VISUAL  AFTER-MOVEMENTS  489 

however,  vanishes  when  one  bears  in  mind  the  cases  where  a 
dust  film  is  seen  even  when  the  after-effects  are  projected 
upon  the  printed  sheets  and  particularly  upon  dark  shadows 
or  cardboards.  This  film  has  been  sufficiently  described  al- 
ready. It  is  exactly  like  fine  particles  of  dust  moving  rap- 
idly through  space.  One  would  not  expect  fading  after-images 
to  be  of  this  nature. 

A  final  objection  to  the  fading  after-image  theory  is  as 
follows:  The  continued  passage  of  a  series  of  stimuli  across 
the  retina  fatigues  the  retinal  elements.  If  the  elements  can 
recover  between  stimulations,  a  movement  will  be  seen. 
This  is  what  actually  occurs.  Now  after  the  stimulation 
has  ceased,  it  is  conceivable  that  one  wave  of  recovery 
(fading  a.-i.)  would  sweep  across  the  retinal  area.  I  see  no 
reason  why  successive  waves  should  do  so.  And  yet  this 
would  be  necessary  in  order  to  secure  such  temporally  ex- 
tended after-effects  as  are  actually  observed. 

In  the  light  of  what  has  gone  before  in  this  paper,  we  are 
therefore  led  to  interpret  visual  after-movement  in  terms  (so 
far  as  the  retina  is  concerned)  of  a  streaming  phenomenon 
which  passes  across  the  retina  in  a  direction  opposite  to  the 
image  of  the  objective  movement.  I  confess  my  ignorance  of 
what  this  streaming  may  be.  It  may  be  lymph  currents,  as 
Ferree  supposes.  It  may  be  an  electrical  phenomenon. 
The  uncertain  status  of  its  exact  nature  cannot,  however, 
overcome  the  necessity  of  its  postulation. 

The  theory  readily  explains  the  phenomena  described: 
The  dust  films  are  the  projections  into  space  of  the  streaming. 
The  s.-a.-m.  is  due  to  the  invisibility  of  the  film  because  of 
the  clear  bold  contours  of  central  vision  as  compared  with 
peripheral  vision.  This  results  in  the  interpretation  of  the 
external  objects  as  moving  in  a  direction  opposite  to  the  film 
and  occurs  under  special  circumstances  only.  In  the  regular 
after-movement  with  the  large  areas,  the  film  is  itself  visible 
and  drags  the  external  objects  along  with  it.  With  small 
areas  the  same  thing  occurs  with  a  minimum  of  film  visibility. 


EXPERIMENTAL  DATA  ON  ERRORS  OF  JUDGMENT 
IN  THE  ESTIMATION  OF  THE  NUMBER  OF 
OBJECTS  IN  MODERATELY  LARGE  SAMPLES, 
WITH  SPECIAL  REFERENCE  TO  PERSONAL 
EQUATION 

BY  J.  ARTHUR  HARRIS 

Carnegie  Institution  of  Washington 

I.     INTRODUCTORY  REMARKS 

In  attempting  to  estimate  the  number  of  a  considerable 
group  of  objects  of  the  same  kind,  the  observer  can  seldom 
state  the  true  number  but  generally  gives  one  which  is  either 
too  high  or  too  low.  If  a  series  of  such  estimates  by  the  same 
observer  be  considered  it  may  be  found  that  there  is  no  ten- 
dency for  the  errors  in  excess  of  the  true  value  to  be  more 
numerous  or  greater  in  amount  than  those  in  defect.  In 
such  a  case  the  average  of  the  deviations  of  the  estimates  from 
the  true  number  of  objects  will  be  sensibly  zero.1  The 
individual  making  the  estimates  may  then  be  said  to  have  no 
personal  equation.  Other  individuals,  however,  may  have  a 
definite  tendency  to  err  on  one  side  of  verity  in  their  evalu- 
ations. Such  may  be  said  to  have  a  positive  or  a  negative 
personal  equation,  as  the  case  may  be. 

Personal  equation  is  not  the  only  factor  which  should  be 
taken  into  account  in  determining  the  rank  of  an  individual 
among  a  number  passing  judgment  upon  the  value  of  any 
magnitude.  An  observer  with  no  consistent  bias  towards 
over  or  under  valuation  may  be  characterized  by  very  erratic 
judgment — assigning  sometimes  a  value  far  in  excess,  at  other 
times  a  value  far  in  defect  of  the  actual.  Thus  consistency 
or  steadiness  of  judgment  is  also  a  characteristic  of  impor- 
tance which  should  be  taken  into  account  in  the  comparison 
of  individuals. 

In  this  paper,  I  have  presented  several  series  of  experi- 

1  The  mean  actually  determined  by  experiment  would  be  o  plus  or  minus  a  smal 
amount  due  to  the  errors  of  sampling. 

49° 


ERRORS  OF  JUDGMENT  49 l 

mental  data  bearing  on  these  questions.  Such  materials, 
properly  analyzed  and  interpreted,  should  be  of  value  to  the 
psychologist.  The  data,  which  are  a  by-product  of  long 
routine  processes  in  experimental  breeding,  are  presented 
solely  for  their  intrinsic  value  as  experimentally  determined 
facts.  The  arrangement  of  the  material  is  that  suggested  by 
the  view  point  of  a  quantitative  biologist,  a  biometrician. 
Comparison,  criticism  and  interpretation  are  left  to  those  hav- 
ing the  necessary  training.  I  trust,  therefore,  that  the  pro- 
fessional psychologist  will  overlook  crudities  in  terminology, 
and  accept  the  experimental  data  for  what  they  may  be  worth 
when  interpreted  from  his  own  point  of  view. 

The  circumstances  leading  to  the  collection  of  these  data 
were  the  following: 

At  various  times,  I  have  found  it  necessary  to  obtain  very 
large  series  of  countings  of  bean  seeds,  either  for  germination 
tests  or  for  determining  the  mean  weights  for  different  series. 
Various  considerations  (which  need  not  be  reviewed  here) 
led  to  the  conclusion  that  the  counting  could  most  easily, 
accurately  and  advantageously  be  carried  out  in  units  of  25, 
50  and  100  seeds.  By  the  slightest  addition  to  our  labor  we 
could  determine  the  accuracy  of  judgment  in  the  estimation 
of  these  lots  of  25,  50,  100  or  200  seeds.  The  advantages  of 
so  doing  were  threefold:  (a)  It  gave  a  means  of  testing  the 
personal  equation  and  the  steadiness  of  judgment  of  the 
three  assistants  who  are  responsible  for  a  large  part  of  the 
routine  work  in  my  laboratory,  (b)  Competition  (for  first 
place  in  accuracy  of  estimation)  added  a  little  spice  to  a  long 
task  which  would  otherwise  have  been  the  most  monotonous 
drudgery,  (c)  It  gave  an  extensive  series  of  data  on  errors  of 
judgment. 

II.     EXPERIMENTAL  METHODS 

The  method  of  the  experiment  was  as  simple  as  can  be 
imagined. 

The  observer  took  from  a  container  a  handful  of  beans  and 
poured  as  nearly  as  possible  a  specified  number  of  seeds  (25, 
50,  100  or  200  according  to  the  experiment)  on  the  table.1 

1  The  seeds  were  poured  upon  a  dark  gray  felt  paper  mat.    This  was  chosen 


492  ]-  A.  HARRIS 

If  there  appeared  to  be  too  few,  more  were  added,  if  too  many, 
a  portion  were  put  back.  The  work  was  carried  out  so  rapidly 
that  there  was  no  possibility  of  counting  assisting  in  the 
estimate.1  The  number  was  then  at  once  determined  by 
counting  and  the  deviation  of  the  sample  from  the  desired 
value  was  noted  and  recorded  by  the  observer  who  made  the 
estimate.  A  persistent  effort  was  made  by  each  observer  to 
improve  in  succeeding  estimates.  The  influence  of  this  con- 
stant checking  upon  personal  equation  and  upon  steadiness  of 
judgment  seems  to  me  the  most  interesting  phase  of  the 
present  study.  It  will  be  considered  in  a  subsequent  paper. 
Except  in  one  special  case  fifty  estimates  were  made  by 
each  observer  in  the  morning  and  another  fifty  in  the  after- 
noon. In  general,  this  was  attended  to  early  in  each  half  day's 
work.  Each  lot  of  fifty  may  be  designated  as  a  period.  The 
periods  were,  with  a  single  exception,  consecutive  except  for 
a  break  over  Sunday.  Ample  details  concerning  the  indiv- 
idual experiments  are  given  below.  Four  individuals  took 
part  in  the  work.2 

The  following  series  of  experiments  were  made: 
A.  Our  first  series  of  experiments  was  made  in  May,  1912. 
The  attempt  was  in  every  instance  to  lay  out  a  sample  of  fifty 
seeds.     Observer  A  made  only  141  estimates  and  these  with 

because  the  color  selected  was  easy  for  the  eye  although  affording  sufficient  contrast 
with  the  (generally)  white  seeds  and  because  the  seeds  do  not  roll  about  as  badly  on 
the  felt  surface.  These  conditions  count  for  rapidity  and  comfort  of  work.  Each  of 
the  observers  occupied  her  own  table,  so  that  light  and  other  conditions  were  perfectly 
familiar  through  long  experience. 

1  The  validity  of  this  statement  will  be  apparent  from  the  fact  that  in  the  first 
experiment  the  average  time  required  for  pouring  out  the  samples  of  fifty  seeds,  counting 
them  twice,  recording  the  deviation  of  the  guess  from  the  true  number,  and  replacing 
slightly  wrinkled  or  weevil  eaten  seeds  by  perfect  ones  was  86  minutes  for  Observer  B, 
83  minutes  for  Observer  C  and  80  minutes  for  Observer  D. 

2  My  own  observations  were  too  few  and  too  continually  broken  into  by  extra- 
neous matters  to  be  of  particular  value.     The  other  three  are  Miss  Edna  K.  Lockwood, 
Miss  Margaret  G.  Gavin  and  Miss  Lily  J.  Gavin.     Each  of  them  has  been  with  me  for 
six  years  or  more.     It  would  be  difficult  to  express  adequately  my  obligation  to  them 
for  their  patient,  conscientious  and  highly  efficient  assistance  in  the  onerous  routine, 
observational,  clerical  and  arithmetical  work  of  a  biometric  laboratory.     For  conven- 
ience the  observers  are  designated  hereafter  by  letters:  Mr.  Harris,  Observer  A  or 
merely  A\  Miss  Gavin,  Observer  C;  Miss  Lockwood,  Observer  B;  Miss  Lily  Gavin, 
Observer  D. 


ERRORS  OF  JUDGMENT  493 


numerous  interruptions.  Observers  B-D  made  each  700 
attempts  at  laying  out  the  required  number.  These  are 
grouped  in  14  periods  of  50  trials  each.  In  the  case  of  B  and 
C  these  were  made  in  the  mornings  and  afternoons  of  seven 
days  which  were  consecutive  except  for  Sunday.  Observer 
D  worked  on  the  same  schedule  but  was  necessarily  absent  one 
afternoon,  hence  the  14  periods  were  distributed  over  8  days. 
The  data  of  this  series  will  be  designated  as  \A^  IB,  1C,  and 
IZ),  the  Roman  numeral  referring  to  the  series  and  the  letter 
to  the  observer. 

B.  The  second  series  of  experiments  was  made  in  Novem- 
ber, 1912.     Again  the  White  Navy  bean  seeds  were  used  and 
the  attempt  was  to  lay  out  samples  of  fifty  seeds  each.     The 
work  covered  a  period  of  two  weeks,  in  which  there  was  a 
morning  and  an  afternoon  period  of  50  estimates  each.     Thus 
there  were  altogether  1,200  estimates  by  each  of  three  ob- 
servers, By  C,  D.     The  estimates  logically  fall  into  two  major 
periods  of  six  days  each,  separated  by  Sunday.     They  are 
therefore  designated  as  series  II.  and  III.     The  appended 
letters  designate  the  subjects,  B-D. 

C.  The  experiments  were  again  taken  up  with  the  White 
Navy  beans  in  February,  1913.    Again  two  weeks  were  devoted 
to  the  work  and  1,200  trials,  in  daily  morning  and  afternoon 
periods  of  50  each,  were  made  by  the  three  individuals  B-D. 
This  time  100  instead  of  50  seeds  was  the  number  aimed  at 
in  the  laying  out  of  the  samples.     The  first  of  the  two  weeks 
may  be  designated  by  IV.,  the  second  by  V. 

D.  The  last  four  days  in  July,  1913,  trials  at  estimating 
200  seeds  were  made  by  B,  C,  and  D.     Four  days'  work  of 
50  trials  per  day  completed  the  countings  that  were  necessary 
for  the  masses  of  Navy  seeds  then  to  be  weighed.     Because 
of  the  time  required  for  the  counting  and  recounting  of  samples 
of  200  seeds  it  was  not  feasible  to  do  more  than  50  estimates 
in    a    day.     These    were    made    consecutively    and    usually 
required  a  full  half  day's  concentrated  work.     Doubling  the 
number  would  have  meant  an  abnormal  mental  and  physical 
effort  for  those  making  the  estimates.     The  experiment  is 
designated  as  VI. 


494  /•  A.  HARRIS 

E.  The  Tuesday  following  the  preceding  set  of  estimates, 
(Aug.  5)  which  were  closed  on  Thursday,  a  set  of  trials  at 
laying  out  25  beans,  of  a  larger-seeded  brown  bean — "Ne  Plus 
Ultra" — was  begun.     Sets  of  50  estimates  in  the  morning 
and  afternoon  were  made  daily  except  for  Saturday  afternoon 
(Aug.  9).    Thus  there  were  9  periods  each  by  C  and  D.    These 
will  be  referred  to  as  VII. 

F.  The  week  immediately  following  the  preceding  trials 
(Aug.  11-16)  Observer  D  did  one  full  week  (12  periods  of  50 
estimates  each)  on  the  "Ne  Plus  Ultra"  seeds;  again  the 
attempt  was  to  lay  out  25  seeds.     Series  VIII. 

G.  For  the  two  weeks  beginning  August  25,   1913,  Ob- 
servers B  and  C  made  trials  at  the  estimation  of  lots  of  25 
seeds,  using  a  White  bean  somewhat  smaller  than  the  Navy 
on  which  the  main  bulk  of  these  experiments  was  based. 
The  first  week  embraced  n  periods,  Saturday  afternoon  being 
out.     The  second  week  included  only  9  periods,  Sunday  and 
Monday  (Labor  Day)  separated  the  two  lots.     The  estimates 
were   closed   with   Saturday   morning  of  the   second   week, 
when  the  supply  of  seeds  which  required  weighing  was  ex- 
hausted.    Note  that  Observer  B  had  made  no  estimates  since 
the  end  of  July  when  she  was  estimating  at  lots  of  200  seeds. 
Observer  C  had  made  no  estimates  since  August  9,  when  she 
was  working  with  large  seeded  brown  beans,  and  estimating 
at  fifties.     The  first  week  forms  series  IX.  and  the  second  X. 

H.  During  the  period  of  May  4  to  May  9,  1914, 
inclusive,  Observers  B-D  made  estimates  twice  daily  at  50 
seeds  of  a  large  brown  bean,  Burpee's  Stringless.  Thus  these 
estimates  were  made  after  a  lapse  of  several  months  (August, 
1913— May,  1914)  since  the  last  trials.  For  convenience  these 
will  be  designated  as  Experiment  XL 

Thus  there  are  altogether  28  sets  of  experiments,  carried 
out  by  three  observers,  distributed  over  a  period  of  two  years, 
and  comprising  a  total  of  15,200  estimates. 

The  analysis  of  the  data  is  carried  out  by  the  modern 
higher  statistics,  the  notation  of  which  is  very  generally 
familiar  or  easily  accessible. 


ERRORS  OF  JUDGMENT 


495 


III.     PRESENTATION  AND  ANALYSIS  OF  DATA 

I.     Personal  Equation 

Data  Tables  A-E  give  the  deviations  of  the  number  of 
seeds  actually  laid  out  from  the  desired  number  (25,  50, 
100  or  200),  i.  e.,  seeds  actually  drawn  less  seeds  intended  to 
be  drawn.  Note  that  the  attempt  was  in  each  case  to  lay 
out  a  definite  number  of  seeds,  say  50.  +15  indicates, 


-IS  -10    -f       0    -f^    4/0  4 Af  42  O 
EXPERIMENT   I    D 


-/O    -S        0    4-5"  +/<? 
EXPERIMENT   I  B 

DIAGRAMS  1-2.  Distribution  of  Errors  of  Estimation  in  Experiment  I.  The 
heights  of  the  ordinates  indicate  the  frequency  of  deviations  of  different  grades. 

therefore,  that  65  instead  of  50,  and  —6  indicates  that  44 
instead  of  50  were  actually  drawn. 

Certain  of  these  series  are  also  represented  graphically  in 
Diagrams  1-2. 

Two  distinct  problems  are  presented  by  these  distributions 
and  graphs.  The  first  is  that  of  personal  equation  properly 
so  called;  the  second  is  that  of  steadiness  of  judgment. 


/•  A.  HARRIS 

By  personal  equation,  we  understand  a  bias  in  a  given 
direction — a  tendency  to  estimate  too  high  or  too  low.  If 
there  be  a  personal  equation,  one  observer  will  tend  regularly 
to  pour  out  too  many  seeds,  just  as  another  will  tend  to  make 
the  sample  too  small.  By  steadiness  of  judgment,  we  mean 
consistency  in  estimation.  One  observer  may  be  more  erratic 
than  another,  estimating  now  far  too  high,  now  far  too 
low. 

These  points  may  to  some  extent  be  illustrated  by  the 
first  two  diagrams.  We  note  that  for  Observer  B  the  fre- 
quencies (represented  by  the  heights  of  the  bars)  of  the  grades 
above  and  below  o  are  about  equal,  while  in  the  case  of  the 
Observer  D  the  frequencies  above  o  are  distinctly  greater  than 
those  below  .  Indeed  in  the  cases  of  Z),  there  are  six  groups  of 
errors  of  observation  above  o  which  contain  more  cases  than 
any  class  below  o.  Apparently  Observer  B  has  little  personal 
equation,  while  D  has  a  pronounced  tendency  to  lay  out  too 
many  seeds — that  is  to  underestimate  the  number  of  objects 
in  a  group.  The  diagrams  also  show  somewhat  the  relative 
steadiness  of  judgment  of  the  two  observers.  The  deviations 
appear  to  be  less  widely  scattered  about  the  mean  in  the  case 
of  B  than  in  that  of  D — judgment  is  apparently  steadier,  less 
erratic. 

Numerically  the  existence  of  personal  equation  may  be 
most  simply  tested  for  by  determining  the  relative  numbers 
of  estimates  in  excess  and  in  defect  of  the  true  value.  For 
convenience  the  tables  have  been  broken  up  into  three  com- 
partments. At  the  head  the  frequency  of  cases  in  which  the 
error  was  o  (i.  e.,  in  which  the  experimenter  actually  succeeded 
in  laying  out  the  number  of  seeds  desired)  is  indicated.  The 
frequencies  of  +  and  —  deviations  of  various  magnitudes  are 
shown  side  by  side  in  the  two  parallel  columns.  The  totals 
of  these  columns  give  the  data  needed  in  answering  in  the 
most  rough  and  ready  manner  the  question  as  to  the  existence 
of  a  personal  equation. 

Of  the  28  experiments  made,  the  totals  of  the  tables  show 
that  in  only  3  cases  is  the  frequency  of  minus  deviations  greater 
than  that  of  plus  deviations.  Or  in  other  words,  in  25  cases 


ERRORS  OF  JUDGMENT 


497 


out  of  28  the  experimenters  in  the  long  run  made  the  error  of 
laying  out  too  many  seeds.1 

In  comparing  the  frequencies  of  +  and  —  deviations  of  the 
same  magnitude  (which  have  been  placed  in  the  tables  in 
parallel  columns  to  facilitate  such  comparison)  it  is  also  clear 
that  in  almost  every  grade  of  deviation  represented  by  a 
material  frequency  the  results  in  excess  of  the  attempted 
number  are  more  numerous  than  these  in  defect. 

With  results  indicating  in  so  striking  a  manner  the  exist- 
ence of  a  pronounced  personal  equation  on  the  part  of  the 
observers,  the  calculation  of  any  probable  error  seems  super- 
fluous, especially  since  probable  errors  are  given  for  a  subse- 
quent test. 

A  measure  of  the  magnitude  of  personal  equation  as  well  as 
a  demonstration  of  its  existence  and  direction  must  be  sought. 
This  is  most  simply  expressed  in  terms  of  the  mean  deviation 
of  the  estimates  from  the  desired  value. 

Since  in  our  experiments  the  attempt  was  made  to  lay  out 
a  sample  of  a  given  size,  an  excess  of  plus  deviations  either 

TABLE  I 

PERSONAL  EQUATION  FOR  INDIVIDUAL  EXPERIMENTS 


Experi- 
ment 

Trials 

Number 
Sought 

Observer  B 

*. 

Observer  C 

«« 

Observer  D 

*, 

I. 

700 

50 

+  .I7ldr.I07 

+    1  .60 

+   .926dr.!O6 

+  8.74 

+2.I70dr.I33 

+16.32 

II. 
III. 

600 
600 

SO 
SO 

+  .5IOdr.098 

+.5iodr.o8o 

+  5-20 

+  6.38 

+  I.O23dr.I04 

+  .s6odr.o89 

+  9-84 
+  6.29 

+    .592dr.I2I 

—  .368dr.ii4 

+  4.89 
-  3.23 

H.+ 

III. 

1,200 

50 

+.5iodr.o63 

+  8.10 

+    .792  dr.  069 

+  11.48 

+   .II2dr.o84 

+  1.33 

IV. 

600 

100 

+.78sdr.i88 

+  4.18 

+  1.043  dr.  197 

+  5-28 

—    .2I2dr.2IO 

—    1  .01 

V. 

600 

100 

+  .28odr.I5I 

+  1.85 

+  5-72 

+    .890dr.I72 

+  5.17 

IV.+ 

V. 

1,200 

IOO 

+.532dr.I2I 

+  440 

+   .968dr.I26 

+  7-68 

+  -339dr.i36 

+  2.49 

VI. 

200 

200 

+.8osdr.057 

+  14.12 

+  I-96odr.058 

+3378 

+3.  05  5  dr.  077 

+39-68 

VII. 

450 

2C 

+   .28odr.o62 

+  4-52 

+  -75l~^~  °9^ 

+  766 

VIII. 

600 

+   .205+  064 

+    3  20 

IX. 

2C 

+  .805  dr.  067 

+  I2.OI 

—  .o6odr.O58 

—  1.03 

X. 

45O 

+  -4"?  3  +-064 

+   6.77 

•••-'j 
+  3.04 

IX.+ 

J 

X. 

1,000 

2C 

_|_  6^8-f-  047 

+  17.  C7 

+   .042  dr.  040 

+  i.  06 

XI. 

600 

SO 

+.l80rh.090 

+    2.00 

+   .22ldr.o87 

+  2.54 

+    .342dr.I2I 

+  2.83 

1  This  is  also  conspicuously  the  case  in  the  short  series  of  trials  by  Observer  A, 
whose  estimates  are  not  to  be  discussed  in  detail. 


498 


/.  A.  HARRIS 


in  number  or  magnitude,  or  both,  is  indicated  by  a  mean  error 
with  the  positive  sign.  This  will  indicate  a  tendency  to  under- 
estimate any  given  quantity,  since  an  actually  larger  number 
than  that  desired  was  laid  out. 

Table  I.  gives  the  results.  Of  the  28  means  for  the  indi- 
vidual experiments  25  have  the  positive  sign,  i.  e.,  in  25  out  of 
28  experiments  the  observers  had  a  tendency  to  lay  out  too 
many  seeds. 

The  results  are  shown  graphically  in  Diagram  3.  Here  the 
signs,  frequencies  and  amounts  of  the  personal  equations  are 
shown  by  the  direction  and  length  of  the  lines.  The  dotted 


ac 

.  EXPERIMENTER    D 

EXPERIMENTER    C 

EXPERIMENTER   B 

2.5 

- 

20 

- 

I.S 

- 

1.0 

1 

C.S 

c.o 

- 

MEAN  PERSONAL 

EQUATION 



MEAN  F 

ERSON, 

L  EQUATION 

MEAN  PERSONAL  EQUATION 

I 

i    ,1 

L    i  ll 

i! 

ZERO  BAR. 

ZERO  BAR          i 

ZERO  BAR 

EXPERIMENT 
J       II      l|l      IV     V      VI    VII  VIII    XI 

EXPERIMENT 
1        II      III      IV     V      VI     V,ll     IX      X      XI 

EXPERIMENT 

,     ii    in    ,y    v    v,    ix    x    xi 

DIAGRAM  3.  Sign  and  Magnitude  of  (Absolute)  Personal  Equation  in  All  the 
Experiments.  The  mean  deviation  from  zero  for  the  several  experiments  is  indicated 
by  the  lengths  of  the  lines.  The  dotted  lines  indicate  the  mean  of  all  the  experiments 
by  the  individual  observers. 

transverse  lines  show  the  mean  values  of  all   the  personal 
equations  for  the  individual  observers. 


ERRORS  OF  JUDGMENT  499 

The  magnitudes  of  these  means  are,  however,  very  low. 
For  Observer  B  there  is  not  a  single  case  in  which  it  amounts  to 
one  seed,  although  in  every  case  it  is  positive  in  sign.  For 
Observers  C  and  D  the  values  are  somewhat  higher.  The 
largest  single  value  is  that  of  Observer  Z),  experiment  VI., 
where  the  estimates  were  on  an  average  three  seeds  off.  In 
this  case  however  there  were  only  200  trials  and  the  attempt 
was  being  made  to  estimate  in  lots  of  200  seeds. 

To  the  question  of  the  actual  magnitude  of  these  deviations 
from  zero  personal  equation  I  shall  return  presently.  For 
the  moment,  the  feature  of  these  results  which  impresses  me 
is  the  fact  that  so  slight  a  personal  bias  should  be  so  persistent 
among  the  three  observers  throughout  the  two  years  during 
which  these  observations  were  carried  on. 

With  regard  to  the  significance  of  the  deviation  of  these 
means  from  o  little  need  be  said.  The  probable  errors  of  the 
mean  have  been  calculated  from  the  usual. 

E  A-.  67449  -=, 


Where  <7  is  the  standard  deviation  of  the  series  of  errors  (to 
be  discussed  shortly)  and  N  the  number  of  observations.  In 
Diagram  3  the  amount  of  the  probable  error  is  indicated  in 
each  case  by  a  cross  on  the  ordinate  indicating  the  amount  of 
personal  equation.  The  ratio  of  the  deviation  of  the  mean 
from  o  to  its  probable  error  has  been  tabled  in  each  case.  Of 
the  36  constants  (including  these  in  which  two  consecutive 
experiments  have  been  combined)  28  are  over  2.5  times  as 
large  as  their  probable  errors.  Of  these,  27  are  positive  and 
one  negative  in  sign.  There  can  be  no  reasonable  question, 
therefore,  of  the  statistical  trustworthiness  of  these  individual 
constants. 

One  may  test  most  critically  the  existence  of  personal 
equation  by  splitting  these  masses  of  observations  up  into 
sub-classes,  say  into  the  groups  of  50  estimates  known  as 
periods.  Constants  must  then  be  determined  for  these  in 
the  same  manner  as  for  the  "  general  population"  as  the  sta- 
tisticians call  it. 

The  detailed  analyses  of  one  series  of  data  in  this  way  is 
sufficient,  since  the  others  will  be  treated  in  a  slightly  different 
manner,  giving  nearly  comparable  end  results,  in  a  subsequent 


500 


/.  A.  HARRIS 


paper.  Table  II.  for  the  first  experiment  furnishes  data  for 
determining  whether  the  personal  equation  demonstrated  in 
the  massed  estimates  is  persistent  throughout  the  course  of 
the  experiment  in  the  individual  periods.  In  Diagram  4  the 
solid  line  in  each  panel,  the  zero  bar,  shows  the  o  average  of 
errors  of  observation  which  would  be  secured  if  there  were  no 

TABLE  II 


Period 

Observer  B 

Observer  C 

Observer  D 

Personal 
Equation 

Steadiness  of 
Judgment 

Personal 
Equation 

Steadiness  of 
Judgment 

Personal 
Equation 

Steadiness  of 
Judgment 

I 

+  1.40 

6.24 

+    -44 

5-34 

+  1.92 

6.85 

2 

+    .82 

5.46 

+  1.84 

4-93 

+2.30 

7-03 

3 

-    .80 

4.10 

+  1.02 

4.13 

+3-88 

4.89 

4 

~    .56 

3-95 

+  I.O2 

3-83 

+3.02 

6.22 

5 

-  -44 

3-69 

+  1-72 

4-30 

+3.78 

5.20 

6 

+    .10 

3-95 

+  2.04 

3-86 

+  1.36 

4.96 

7 

+  -32 

4-23 

+  1.24 

4-OS 

+  2.58 

4-75 

8 

-  .72 

3.87 

+    -SO 

3-75 

+  1.22 

3-95 

9 

+  .90 

3-79 

+  1.40 

4.22 

+  I-SO 

4-34 

10 

+2.04 

3-88 

+    .18 

4-50 

+  1-74 

4-13 

ii 

+    .20 

3  -75 

+    -SO 

3-35 

+  1.04 

4.07 

12 

+    .32 

4.11 

~    .36 

3.66 

+  1.68 

3-95 

13 

-    .44 

346 

+  1.06 

3-70 

+  .80 

542 

H 

~    -58 

3-23 

+    .36 

2.96 

+3.56 

445 

personal  equation — i.  e.,  no  bias  towards  too  high  or  too  low 
estimates.  The  circles  show  the  actual  means  for  the  14  in- 
dividual periods  of  50  estimates  each.  The  light  line  shows 
the  mean  deviation  for  the  whole  14  periods,  the  amount  of 
which  is  forcibly  brought  out  by  the  shaded  area.  The  sloping 
lines  show  the  rate  of  change.  These  will  be  discussed  later. 
For  the  whole  series  of  observations,  Observer  B  had  within 
the  limits  of  the  probable  error,  no  personal  equation,  i.  <?., 
her  mean  deviation  from  the  true  value  was  only  +  .171  ±  .107. 
Here  it  appears  that  in  8  of  the  periods  her  means  fall  above 
and  in  6  of  the  periods  below  the  o  bar.  For  Observer  C, 
who  appeared  from  the  massed  observations  to  have  a  distinct 
personal  equation  of  about  one  seed,  the  diagram  shows  that 
in  13  out  of  14  cases  the  period  means  fall  on  the  positive  side 
of  the  line.  Finally,  for  Observer  Z),  who  in  this  series  has 
the  greatest  bias  of  the  three  towards  underestimating  the 
number  of  seeds  in  a  sample — that  is,  towards  laying  out  too 
many  seeds  in  the  attempt  to  get  50 — all  14  period  means  are 
positive. 


ERRORS  OF  JUDGMENT 


501 


EXPERIMENTER    B 


EXPERIMENTER   C 


EXPERIMENTER    D 


MEAN    R  E. 


ZERO   BAR 


/        2       3       4        €       6        7        8        <?       /O       II      12      /3 
PERIOD    IN    THE     EXPERIMENT 


DIAGRAM  4.  Personal  Equation  in  the  Fourteen  Individual  Periods,  Each  of 
Fifty  Trials,  of  Experiment  I.  The  circles  indicate  the  personal  equation  for  the 
individual  periods.  The  shaded  area  shows  the  amount  of  personal  equation  for  the 
whole  experiment. 


502 


/.  A.  HARRIS 


With  regard  to  the  actual  magnitude  of  the  personal 
equation,  it  seems  reasonable  to  assume  that  if  there  be  a 
tendency  to  err  from  the  true  value  in  any  definite  direction, 
the  actual  mean  deviation  observed  will  be  to  some  degree 
dependent  upon  the  number  of  objects  with  which  the  ex- 
perimenter is  dealing. 

The  simplest  assumption  is  that  the  actual  amount  of  the 
personal  equation  in  any  given  case  should  be  approximately 
proportional  to  the  number  which  the  experimenter  is  at- 
tempting to  estimate.  On  such  an  assumption  (which  on 
more  extensive  investigation  may  or  may  not  be  found  to  be 
borne  out  by  the  experimental  facts)  one  may  take  the  ratio 
of  the  actually  observed  mean  deviation  to  the  ideal  number. 
Concretely,  one  divides  the  measures  of  personal  equation 
given  in  Table  I.  by  25,  50,  100  or  200  as  the  case  may  be. 
Expressed  in  this  way  we  have  an  'error  per  object,'  or  a 

TABLE  III 

RELATIVE  PERSONAL  EQUATION  AND  DIFFERENCES  IN  RELATIVE  PERSONAL  EQUATION 
FOR  THREE  OBSERVERS  IN  THE  INDIVIDUAL  EXPERIMENT 


'Series 

Observer  B 

Observer  C 

Observer  D 

D—  C 

D  —  B 

C-B 

I. 

+  -0034 

+  .OI8S 

+  .0434 

+.0248 

+  •0399 

+  .0151 

II. 

+.OIO2 

+  .0204 

+  .0118 

-.0086 

+  .OOI6 

+  .OI02 

III. 

+.OIO2 

+  .0112 

-.0073 

—  .0185 

-.0175 

+  .OOIO 

II.+III. 

+.OIO2 

+.OIS8 

+  .OO22 

—  .0136 

-.0079 

+  .0056 

IV. 

+.0078 

+.0104 

—  .0021 

—  .0125 

-.0099 

+  .0025 

V. 

+  .0028 

+  .0089 

+  .0089 

—  .OOOO 

+  .006I 

+  .006l 

IV.  +V. 

+.0053 

+.0096 

+  .0033 

-.0062 

—  .0019 

+  .0043 

VI. 

+.OO40 

+  .0098 

+  .0152 

+.0254 

+  .0112 

+  .0057 

VII 

+.OII2 

+  .O3OO 

+  .0188 

VIII 

+  .OO82 

IX 

4-  O322 

—  .OO24 

—  .O34.6 

x 

4-  OI73 

+.0066 

•w^w 
—  .OIOO 

IX  +X 

_l-  O2CC 

-j-.ooi6 

—  0238 

XL 

+  .0036 

+.0044 

+  .0068 

+.0024 

+.OO32 

+  .0008 

'relative  personal  equation.'  The  resulting  values  are  given 
in  Table  III. 

The  individual  entries  and  the  averages  show  that  the 
relative  personal  equation  is  low.  The  observers  tend  to  lay 
out  about  i  per  cent,  too  many  seeds. 

Comparisons  between  the  different  workers  are  possible  on 
the  basis  of  these  relative  values  which  may  be  averaged. 

From    the    differences    for    the    individual    experiments 


ERRORS  OF  JUDGMENT 


5<>3 


(leaving  the  combined  series  out  of  account)  the  following  facts 
are  to  be  noted. 

Observer  B  has  a  higher  personal  equation  than  Observer  C 
in  2  cases  and  a  lower  personal  equation  in  7  cases.  The 
average  difference  between  them  in  terms  of  relative  personal 
equation  is  only  .0004.  Observer  B  has  a  higher  personal 
equation  than  D  in  2  cases  and  a  lower  deviation  in  5  cases. 
The  average  differences,  regarding  signs  as  before,  is  only 
.0050.  A  comparison  of  the  records  of  Observers  C  and  D 
shows  that  in  4  experiments  Observer  D  has  a  greater  personal 
equation  than  C  whereas  in  the  other  4  experiments  precisely 
the  opposite  conditions  prevailed.  The  average  difference  is 
only  .0040. 

From  these  experimental  data  taken  as  a  whole  one  cannot 
conclude  that  there  is  any  demonstrated  difference  between 
the  personal  equation  of  the  three  observers.  All  have  a  bias 
in  the  direction  of  laying  out  more  than  the  intended  number 
of  seeds,  but  that  one  is  worse  than  another  cannot  be 
asserted. 

If  now  one  considers  these  differences  between  the  personal 
equations  of  the  three  observers  in  their  relation  to  their 
probable  errors,  as  shown  for  the  differences  in  the  absolute 
values  given  in  Table  IV.,  it  appears  that  in  a  high  proportion 
of  the  cases  they  are  statistically  significant.  This  is  true  in 

TABLE  IV 

DIFFERENCES  IN  PERSONAL  EQUATION  FOR  INDIVIDUAL  OBSERVERS 


Experi- 

Diff. 

Diff. 

Diff. 

ment 

D—C 

£Diff. 

D—  B 

•^Diff. 

C—  B 

•^Diff. 

I. 

-fi.244zb.i70 

+   7-32 

+  1-999  ±-171 

+  11.69 

+  .755±.i5i 

+   5-00 

II. 

—  43i=b.i6o 

-    2.69 

+   .082±.IS6 

+    -53 

+  -5i3±.i43 

+  3-59 

III. 

-  .928±.i45 

—   6.40 

-  .878^.139 

-  6.32 

+   .050±.I2O 

+     .42 

II.+III. 

—  .68o±.io9 

-   6.24 

—  .3981*1.105 

-  3-79 

+  .282±.093 

+  3-03 

IV. 

—  1.255±.288 

-   4.36 

-  .997^.282 

-  3-54 

+  .258^.272 

+     -95 

V. 

—  .003^.232 

—       .01 

+    .6lO±.229 

+  2.66 

+  .6i3±.2i7 

+  2.82 

IV.+V. 

—  .629^.185 

-    340 

—  .I93±.i82 

-  1.06 

+  .436±.i75 

+  2.49 

VI. 

+  1.095  ±.096 

+  11-41 

+2.25o±.096 

+23-44 

+  I.i55±.o8i 

+  14.26 

VII 

+      A7T4-   Tl6 

+    A.06 

VIII. 

IX. 

—  .865±.o88 

—  9.8i 

X. 

—  .266±.o84 

—   -i.  17 

IX.+X. 

—  .<;Q6±.o62 

*  V 

—   Q.OI 

XL 

+    .121  ±.149 

+     .81 

+  .162^.151 

+  1.07 

+  .041^.125 

+      -33 

I 

504  /.  A.  HARRIS 

cases  in  which  (for  example)  B  has  a  greater  personal  equation 
than  C  as  well  as  in  these  in  which  she  has  a  smaller  personal 
equation.  The  reader  may  compare  the  entries  in  Table  IV. 
for  details. 

The  statement  that  there  are  statistically  significant  dif- 
ferences between  two  observers  for  individual  experiments, 
and  that  these  differences  are  sometimes  positive  and  some- 
times negative  may  be  taken  at  once  by  that  still  considerable 
body  of  students  who  are  hostile  to  the  newer  statistical  tools 
of  research  to  discredit  entirely  the  methods  employed  and 
to  cast  doubt  upon  the  conclusions  just  drawn.  Such  an 
attitude  seems  to  me  quite  unjustified. 

The  true  interpretation  of  the  results  seems  to  me  to  be 
rather  that  the  observers  vary  somewhat  in  their  personal 
equation  from  experiment  to  experiment,  just  as  they  vary 
from  time  to  time  in  general  health,  physiological  tone,  and 
mental  vigor,  alertness,  or  whatever  one  may  care  to  call  it. 
As  a  result  of  this  variation  from  time  to  time  one  observer 
may  show  an  abnormally  high  personal  equation  in  a  partic- 
ular experiment  in  which  a  second  observer  shows  an  un- 
usually low  one.  On  an  other  occasion  the  condition  may  be 
exactly  reversed. 

Thus  in  an  individual  experiment  one  observer  may  seem 
to  be  decidedly  better  than  another.  In  the  long  run  there  is 
no  fully  demonstrated  difference  between  them. 

2.     Steadiness  of  Judgment 

Steadiness  of  judgment  will  best  be  measured  by  some 
expression  showing  the  scatter  of  estimates  around  their 
mean.  The  best  constant  for  this  is  the  standard  deviation,  a. 


o  -TV   _    /Sum  of  (deviations  from  mean)2, 
\  Total  estimates 

which  here  is  most  easily  calculated  from  the  formula1 
S.D.  = 


where  S  is  the  conventional  summation  sign,  N  is  the  number 
of  estimates  and  d  indicates  the  deviation  of  the  estimate  from 
1  Sheppard's  modification  has  not  been  applied  to  the  second  moment. 


ERRORS  OF  JUDGMENT 


5<>5 


the  true  number  of  objects,  i.  e.,  the  actual  number  laid  out 
less  the  required  number. 

The  constants  with  their  probable  errors  are  given  in  the 
first  three  constant  columns  of  Table  V. 

TABLE  V 


Experiment 

Standard  Deviation 

Coefficient  of  Variation 

Observer  B 

Observer  C 

Observer  D 

Observer  B 

Observer  C 

Observer  D 

I. 

4.180^.075 

4.I39db.075 

5.2Ild=.094 

8-331 

8.128 

9.989 

II. 

3.552^.069 

3-774db.o74 

4.407  ±.  086 

7.032 

*      7-397 

8.7II 

III. 

2.899^.056 

3.  243  ±.  063 

4.i37±.o8i 

5-739 

6.414 

8-335 

II.+IH. 

3.  242  dr.  045 

3.527dz.049 

4.301^.059 

6.418 

6.943 

8.583 

IV. 

6.839^.133 

7.i6o±.i39 

7.635^.149 

6.785 

7.086 

7.65I 

V. 

5.498^.107 

5.682±.in 

6.248d=.I22 

S483 

5.632 

6.193 

IV.+V. 

6.2io±.o86 

6.464^.089 

6.998±.096 

6.177 

6.402 

6.974 

VI. 

1  1.  928  ±.040 

1  2.  089  dz.  04  1 

i6.i72d=.055 

S-940 

5.986 

7.964 

VII. 

I.937d=.O44 

/?.O72±.o6o 

7.663 

II.Q2Q 

VIII. 

2.3I4±.O4t; 

o.1  70 

IX. 

2  •j'j-j-l-  oj.8 

2    OT3  +    O^T 

O  O4.2 

8  072 

X. 

2  OTO-f-  045 

I  7IA-4-  O3O 

7  OO4. 

6.813 

IX.-f-X. 

2  2O2-{-  033 

i  887±  028 

8.587 

y.C'ic 

XL 

3.255zfc.063 

3.i47dz.o6i 

4.399±.o86 

6.486 

6.166 

8.738 

For  steadiness  of  judgment,  we  have  no  absolute  standard 
comparable  to  a  mean  deviation  of  o  in  the  personal  equation 
test.  The  accuracy  of  an  observer  must  be  estimated  by 
comparison  with  others.  A  relative  measure  of  steadiness  of 
judgment  permitting  comparison  between  different  kinds  of 
experiments  is  desirable.  Since  it  is  reasonable  to  suppose 
a  priori  that  errors  of  estimation  will  be  larger  when  the  ob- 
server is  attempting  to  lay  out  samples  of  a  large  number  of 
seeds  than  when  she  is  dealing  with  a  small  number,1  this 
relative  measure  is  best  furnished  by  the  biometrican's  coef- 
ficient of  variation,  which  is  obtained  in  this  case  by  dividing 
the  standard  deviation  multiplied  by  100  by  the  ideal  number 
plus  or  minus  the  observed  personal  equation,  as  the  sign  of 
the  latter  may  indicate. 

These  relative  measures  of  steadiness  of  judgment  are 
given  in  the  last  three  columns  of  Table  V. 

The  differences  in  standard  deviation  measuring  steadiness 

1  Should  the  number  be  made  very  small  indeed  there  would  be  practically  no 
error  of  estimation  after  a  little  experience,  since  the  observer  could  all  but  invariably 
lay  out  the  correct  number. 


J.  A.  HARRIS 


of  judgment  between  the  three  observers  are  set  forth  with 
their  probable  errors  and  their  ratios  to  their  probable  errors 

in  Table  VI. 

TABLE  VI 

DIFFERENCE  IN  STANDARD  DEVIATION  FOR  INDIVIDUAL  OBSERVERS,  THAT  is,  DIFFER- 
ENCE IN  STEADINESS  OF  JUDGMENT 


Experi- 
ment 

D-C 

Diff. 
^Diff. 

D  —  B 

Diff. 
^Diflf. 

C—  B 

Diff. 
^Diff. 

I. 

+  I.O72zfc.I2O 

+   8.93 

+  I.O3I±.I20 

+  8.59 

—  .04i±.io6 

-   0.39 

II. 

+  .633±.ii3 

+  S-6o 

+  .8ssdb.no 

+  7-77 

+  .222±.IOI 

+    2.  2O 

III. 

+  .894±.io2 

+  8.76 

+  1.238^.098 

+  12.63 

+  .344±.084 

+  4-10 

II.+III. 

+  .774=11.076 

+  10.18 

+  1.05  9  ±.074 

+  H-3I 

+.28s±.o66 

+  4.32 

IV. 

+  .475  ±.204 

+  2.33 

+  .796^.200 

+  3-98 

+  .32Izb.I92 

+  1.67 

V. 

+  .566^.165 

+  3-43 

+    .75Odz.l62 

+  4-63 

+.i84db.iS4 

+  1.19 

IV.  +V. 

+  .534^.131 

+  4.08 

+  .788±.I29 

+  2.05 

VI. 

+4.083  ±.069 

+59-17 

+4.244dz.o68 

+62.41 

+.i6i±.os7 

+  2.82 

VII 

-4-1  i^ci  082 

+  13.84 

VIII 

•* 

IX 

—  .3  20+  .063 

—  «;  08 

x 

—  .2Q6+-OCO 

—    5.O2 

IX  +X. 

—  .-j  ic  d=.O43 

—  7-33 

XI. 

+  I.2S2±.I05 

+  11.92 

+  I.i44±.io7 

+  10.69 

—  .io8±.o87 

-  1.24 

The  differences  for  the  standard  deviations  of  the  three 
observers  are  more  consistent  than  those  for  personal  equation. 
Observer  B  has  more  erratic  judgment  than  C  in  4  cases,  less 
erratic  in  5  cases.  In  5  out  of  the  9  cases  the  difference  may  be 
considered  to  be  significant  with  regard  to  its  probable  errors. 
In  2  of  the  experiments  it  is  Observer  B  who  is  significantly 
more  variable  in  estimation,  while  in  3  cases  it  is  Observer  C 
who  has  the  most  irregular  estimates.  These  significant 
differences  which  differ  in  sign  from  experiment  to  experiment 
are  probably  to  be  explained  in  the  same  way  as  those  in 
personal  equation  discussed  above.  The  relative  steadiness 
of  judgment  as  measured  by  the  coefficient  of  variation  shows 
a  mean  of  6.971  in  the  case  of  Observer  B  as  compared  with 
6.946  in  the  case  of  Observer  C,  a  difference  of  only  0.025! 
Thus  in  the  long  run  there  is  no  discernible  difference  in  the 
steadiness  of  judgment  of  B  and  C,  although  in  the  case  of 
individual  experiments  now  one,  now  the  other,  may  be  higher. 

For  the  comparison  between  both  B  and  D  and  C  and  D 
the  case  is  quite  different.  In  every  individual  experiment 
Observer  D  has  a  higher  standard  deviation,  or  in  other  words 


ERRORS  OF  JUDGMENT 


5<>7 


less  steady  judgment,  than  either  B  or  C.  In  practically  every 
instance  the  differences  may  be  considered  significant  in 
comparison  with  their  probable  errors.  The  average  relative 
scatter  of  estimates  of  Observer  D  as  measured  by  the  coef- 
ficient of  variation  is  8.743,  a  value  about  1.80  higher  than 
that  of  either  of  the  other  observers. 

III.     RECAPITULATION 

The  purpose  of  this  paper,  and  of  another  on  the  influence 
of  previous  experience  upon  errors  of  judgment  which  is  to 
follow,  is  the  presentation  in  terms  as  succinct  as  possible  of 
the  results  of  a  series  of  experiments  on  errors  of  judgment  in 
the  estimation  of  moderately  large  numbers  of  objects. 

DATA  TABLE  A 


Amount 
of  Error 

I.  A 

I.  B 

I.  C 

l.D 

II.  B 

II.  C 

II.  D 

III.  B 

III.  C 

III.  D 

0 

4 

61 

79 

4i 

62 

64 

61 

76 

80 

61 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

-r 

- 

-r 

- 

-r 

— 

I 

7 



60 

73 

64 

18 

10 

42 

77 

62 

73 

63 

60 

18 

76 

69 

77 

64 

11 

2 

8 

9 

61 

13 

63 

61 

63 

43 

16 

17 

61 

34 

11 

18 

71 

14 

13 

ij6 

44 

61 

3 

8 

9 

65 

55 

58 

46 

56 

42 

38 

44 

49 

44 

53 

43 

70 

38 

56 

43 

43 

47 

4 

6 

3 

S^ 

32 

44 

36 

49 

22 

38 

41 

1i 

1C 

27 

34 

10 

21 

38 

28 

30 

Ii 

5 

7 

9 

33 

36 

42 

22 

46 

18 

31 

20 

39 

16 

27 

22 

18 

22 

31 

16 

21 

32 

6 

8 

I 

19 

18 

32 

14 

48 

8 

18 

9 

22 

12 

20 

14 

8 

6 

17 

ii 

13 

18 

7 

7 

6 

20 

17 

31 

II 

14 

6 

14 

4 

19 

9 

8 

4 

10 

4 

13 

8 

4 

3 

6 

9 

6 

33 

10 

9 

4 

12 

3 

10 

6 

3 

i 

4 

2 

6 

16 

9 

5 

i 

9 

7 

7 

2 

19 

6 

6 

7 

2 

5 

5 

i 

— 

i 

— 

5 

5 

10 

5 

3 

4 

3 

7 

2 

12 

3 

2 

— 

2 

2 

5 

i 

— 

— 

3 

— 

3 

3 

ii 

7 

— 

2 

i 

3 

I 

13 

2 

— 

— 

I 

2 

3 

i 

— 

— 

2 

— 

i 

— 

12 

i 

— 

I 

2 

2 

I 

7 

3 

2 

— 

I 

I 

— 

— 

— 

— 

— 

— 

2 

2 

13 

3 

i 

3 

— 

4 

— 

5 

— 

— 

— 

I 

— 

i 

— 

— 

— 

— 

— 

— 

— 

IS 

3 

— 

— 

— 

i 

— 

4 
i 

i 

16 

3 

— 

i 

7 

4 

iS 

— 

— 

— 



I 

3 

19 

22 

— 

— 

23 
32 

I 

— 

91 

46 

330 

309 

361 

260 

447 

212 

295 

243 

338 

I98 

288 

251 

309 

215 

296 

224 

243 

296 

The  experiments  consisted  in  attempts  to  lay  out  samples 
of  a  definite  number  of  small  objects.  The  number  which 
the  observer  was  attempting  to  obtain  in  each  sample  (25,  50, 


5°8 


/.  A.  HARRIS 


100,  or  200)  was  constant  for  considerable  periods.  The  error 
of  each  estimate  was  at  once  determined  and  recorded  by  the 
experimenter,  who  on  the  basis  of  these  known  errors  made  a 
continuous  effort  to  improve  in  accuracy  of  estimating. 

Two  characteristics  of  the  series  of  errors  of  estimation 
made  by  the  three  observers  are  here  considered — personal 
equation  and  steadiness  of  judgment.  By  personal  equation 

DATA  TABLE  B 


Amount 
of  Error 

IV 

B 

IV 

.C 

IV 

D 

V. 

B 

V. 

C 

V. 

D 

VI] 

.  C 

VII 

.D 

0 

3 

i 

3 

7 

2 

7 

4 

7 

3 

0 

4 

7 

9 

5 

6 

6 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

-f 

- 

+ 

- 

+ 

- 

I 

37 

34 

32 

28 

31 

35 

49 

42 

47 

43 

35 

32 

86 

69 

63 

57 

2 

34 

34 

32 

31 

27 

30 

44 

42 

46 

40 

47 

36 

63 

52 

52 

3 

34 

31 

44 

27 

18 

42 

36 

29 

34 

37 

38 

29 

28 

2O 

36 

25 

4 

33 

31 

34 

25 

23 

35 

36 

28 

29 

24 

33 

29 

21 

9 

28 

22 

5 

25 

25 

20 

22 

22 

31 

27 

28 

33 

30 

34 

27 

4 

i 

16 

4 

6 

20 

29 

30 

2O 

31 

35 

23 

30 

19 

29 

16 

i 

i 

8 

i 

7 

20 

17 

14 

24 

24 

17 

16 

22 

23 

21 

20 

16 

— 

— 

6 

— 

8 

12 

22 

19 

10 

13 

19 

10 

12 

2<; 

16 

20 

15 

— 

— 

4 

— 

9 

29 

10 

17 

14 

9 

18 

ii 

18 

10 

12 

12 

— 

— 

3 

— 

10 

IO 

7 

21 

8 

IO 

16 

ii 

2 

7 

5 

9 

6 

— 

— 

i 

— 

ii 

9 

8 

14 

12 

8 

9 

10 

6 

4 

2 

5 

4 

— 

— 

i 

— 

12 

6 

5 

II 

6 

9 

6 

3 

4 

7 

3 

13 

5 

— 

— 

i 

— 

13 

ii 

5 

8 

4 

7 

5 

3 

i 

IO 

i 

3 

2 

— 

— 

— 

— 

14 

3 

3 

6 

i 

9 

2 

2 

i 

2 

i 

6 

2 

— 

— 

— 

— 

IS 

6 

3 

7 

6 

4 

4 

3 

— 

— 

I 

i 

3 

— 

— 

i 

— 

16 

4 

i 

3 

i 

2 

3 

— 

I 

— 

i 

2 

— 

— 

— 

— 

17 

4 

i 

3 

— 

4 

— 

i 

— 

I 

— 

6 

I 

— 

— 

— 

— 

18 

i 

— 

2 

i 

i 

2 

— 

— 

I 

— 

i 



— 

— 

— 

— 

19 

4 

— 

I 

i 

2 

I 

— 

— 

— 

— 

— 

I 

— 

— 

— 

— 

20 

— 

— 

— 

i 

2 

— 

— 

— 

— 

— 

i 



— 

— 

i 

— 

21 

— 

— 

— 

— 

3 

I 

— 

— 

I 

— 

i 



— 

— 

— 

— 

22 

— 

— 

i 

— 

— 

— 

— 

— 

I 

— 

— 



— 

— 

— 

— 

23 

24 

25 

— 

— 

i 

— 

— 

3 

— 

— 

— 

— 

— 

•  — 

— 

— 

— 

— 

27 

32 

— 

— 

— 

— 

i 

— 

— 

— 

— 

— 

— 

— 

— 

— 

— 

303 

266 

320 

243 

259 

314 

288 

265 

317 

253 

315 

238 

203 

152 

223 

161 

we  understand  a  bias  in  a  given  direction — a  tendency  to 
estimate  too  high  or  too  low.  By  steadiness  of  judgment  we 
mean  consistency  in  estimation  as  measured  by  the  closeness 
with  which  the  errors  of  estimation  clusters  around  their 
mean  value. 

Personal  equation  is  measured  by  the  mean  (regarding 
signs)  of  the  deviations  of  the  samples  from  their  ideal  value. 


ERRORS  OF  JUDGMENT 


5°9 


Steadiness  of  judgment  is  expressed  in  the  absolute  terms  of 
the  standard  deviation  of  the  errors  of  estimation  about  their 
mean,  or  in  the  relative  terms  of  the  coefficient  of  variation. 
In  the  case  of  all  three  observers  there  is  a  slight  but  sig- 
nificant personal  equation,  which,  notwithstanding  the 

DATA  TABLE  C 


Amount  of 
Error 

VI.  B 

VI.  C 

VI.  D 

0 

6 

8 

i 

+ 

- 

+ 

- 

+ 

- 

I 

7 

5 

3 

7 

8 

3 

2 

8 

5 

4 

8 

6 

S 

3 

3 

7 

i 

4 

6 

4 

4 

— 

4 

10 

S 

7 

2 

5 

5 

8 

5 

3 

6 

4 

6 

8 

2 

10 

3 

7 

4 

7 

8 

I 

S 

8 

5 

4 

8 

3 

3 

5 

— 

S 

2 

9 

8 

4 

10 

4 

4 

2 

10 

9 

4 

9 

2 

7 

5 

ii 

6 

S 

8 

6 

S 

12 

5 

3 

2 

2 

5 

S 

13 

i 

S 

2 

2 

9 

6 

H 

4 

2 

6 

4 

4 

3 

15 

3 

2 

4 

3 

i 

— 

16 

6 

4 

3 

i 

2 

3 

17 

i 

i 

S 

2 

2 

2 

18 

2 

— 

2 

4 

4 

I 

19 

3 

i 

3 

2 

4 

3 

20 

2 

2 

— 

— 

— 

2 

21 

2 

I 

— 

I 

3 

3 

22 

2 

2 

2 

— 

3 

2 

23 

2 



I 

I 

2 

I 

24 

2 

S 

2 

I 

— 

2 

25 



I 

I 

I 

3 

2 

26 

3 

— 

2 

— 

I 

27 

i 

2 

2 

2 

2 

I 

28 

— 

3 

I 



2 

— 

29 

— 

— 

— 

2 

2 

I 

30 

— 

2 

I 

— 

3 

— 

31 

— 

I 

— 

— 



— 

32 

— 

I 

— 

— 



— 

33 

i 



— 

I 

I 

— 

34 

— 

I 

— 

— 



— 

35 

— 



I 

I 

I 

I 

36 

— 



— 

— 



— 

37 

i 



— 

I 

I 

— 

38 

— 



I 

— 



I 

39 

— 

' 

— 

— 



— 

40 

— 



— 

— 

I 

— 

42 

— 



— 

— 

I 

I 

43 

i 



— 

— 



— 

7i 

— 



— 

— 

I 

— 

107 

87 

Ill 

81 

123 

76 

/.  A.  HARRIS 


constant  effort  to  improve,  persisted  throughout  the  two 
years  during  which  the  experiments  were  intermittently  made. 
In  only  three  out  of  the  twenty-eight  experiments  did  the 
observer  lay  out  samples  of  too  small  average  size.  In  a 
large  number  of  the  individual  experiments  the  personal 
equation  is  certainly  statistically  significant  (trustworthy)  in 
comparison  with  its  probable  error. 

It  is  impossible  on  the  basis  of  the  present  series  of  experi- 
ments, extensive  though  it  is,  to  assert  that  the  personal 

DATA  TABLE  D 


Amount  of 

VIII.  D 

IX.  B 

IX.  C 

X.  B 

X.  C 

Error 

0 

103 

83 

116 

82 

109 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

+ 

- 

I 

97 

97 

91 

70 

91 

104 

74 

72 

99 

82 

2 

79 

52 

50 

68 

79 

45 

48 

48 

3 

35 

56 

24 

34 

38 

34 

23 

28 

19 

4 

28 

20 

35 

13 

22 

16 

23 

9 

9 

4 

5 

8 

7 

13 

2 

5 

3 

7 

i 

2 

— 

6 

8 

i 

ii 

I 

I 

2 

i 

— 

— 

i 

7 

i 

2 

3 



— 



— 

— 

I 

— 

8 

i 



i 



— 

— 

— 

— 

— 

— 

9 

i 



— 



— 

— 

— 

— 

— 

— 

10 

— 



i 



— 

— 

~~ 

— 

~~ 

— 

264 

233 

305 

162 

203 

231 

218 

ISO 

I87 

154 

equation  of  any  one  of  the  three  observers  is  on  the  whole 
higher  than  that  of  the  others,  although  the  figures  do  suggest 
that  the  bias  of  observer  D  may  be  slightly  greater  than  that  of 
either  of  the  others.  In  the  case  of  individual  experiments 
there  may  be  significant  differences  between  two  observers. 
In  one  experiment  x  may  have  a  decidedly  lower  personal 
equation  than  y,  while  in  another  period  of  observation 
exactly  the  reverse  condition  may  be  found.  This  is  taken 
to  indicate  a  variation  in  the  magnitude  of  the  personal  equa- 
tion of  an  observer  from  experiment  to  experiment. 

For  steadiness  of  judgment  there  is  no  absolute  standard 
comparable  with  the  zero  mean  deviation  of  the  personal 
equation.  The  data  show  a  coefficient  of  variation  about  6.9 
per  cent,  in  the  case  of  Observers  B  and  C,  and  of  8.7  per  cent, 
the  case  of  Observer  Z),  who  has  a  decidedly  greater  scatter 
in  her  estimates — that  is  a  far  less  steady  judgment — than 


ERRORS  OF  JUDGMENT 


either  of  the  other  observers.  Indeed,  in  every  individual 
experiment  her  standard  deviation  is  higher  than  that  of 
either  of  the  two  other  experimenters. 

Thus  while  there  is  no  certain  differentiation  among  the 
experimenters  in  personal  equation,  they  differ  distinctly  in 
steadiness  of  judgment. 

For  a  more  detailed  consideration  of  these  two  character- 
istics the  reader  must  see  the  subsequent  paper. 

Finally,  I  must  emphasize  again  the  fact  that  these  data 

DATA  TABLE  E 


Amount  of  Error 

XL  B 

XI.  C 

XI.  D 

0 

7i 

78 

S* 

+ 

- 

+ 

- 

+ 

- 

I 

68 

72 

66 

86 

55 

5° 

2 

57 

57 

64 

59 

50 

55 

3 

58 

49 

48 

50 

5i 

40 

4 

40 

28 

33 

23 

40 

36 

5 

23 

26 

25 

23 

24 

27 

6 

12 

12 

13 

7 

20 

22 

7 

II 

6 

10 

6 

17 

II 

8 

4 

i 

2 

2 

ii 

10 

9 

i 

2 

2 

I 

7 

4 

10 

— 

I 

— 



5 

i 

ii 

— 

— 

I 

— 

3 

i 

12 

i 

— 

— 

— 

3 

— 

13 

— 

— 

— 

— 

i 

I 

14 

— 

— 

— 

— 

— 

— 

15 

— 

— 

I 

— 

— 

— 

16 

— 

— 

— 

— 

2 

— 

19 

— 

— 

— 

— 

— 

i 

275 

254 

265 

257 

289 

259 

are  presented  purely  for  their  intrinsic  value.  They  were 
secured  quite  incidentally  in  the  carrying  out  of  large  plant 
breeding  experiments.  The  chief  value  of  the  observations 
perhaps  lies  in  the  fact  that  they  represent  far  larger  experi- 
ments than  the  average  professional  psychologist  is  able  to 
make.  Comprising  as  they  do  28  experiments  due  to  three  ob- 
servers all  of  whom  carried  on  the  work  at  considerably  sepa- 
rated intervals  over  a  period  of  two  years,  during  which  they 
made  over  15,000  estimates,  the  constants  have  a  reliability 
which  cannot  possibly  be  attributed  to  short  series.  Purely 
psychological  discussions,  even  the  review  of  literature  with 
some  of  which  the  writer  is  quite  familiar,  is  left  to  specialists. 


ORIGIN  OF  HIGHER  ORDERS  OF   COMBINATION 

TONES1 

BY  JOSEPH  PETERSON 

University  of  Minnesota 

It  is  well-known  that  Helmholtz  gave  three  or  more 
different  explanations  of  the  origin  of  combination  tones. 
According  to  his  own  statements  combination  tones  may  be 
generated  (i)  from  the  clicking  action  between  the  hammer 
and  the  anvil  of  the  ear,  when  the  primaries  are  powerful;2 

(2)  from  the  asymmetry  in  vibration  of  the  tympanum;  and 

(3)  from  disturbed  superposition  of  vibrations  due  to  some 
objective  connection  between  the  primary  periodicities,  such 
as  a  common  windchest  found  in  the  polyphonic  siren  or  the 
harmonium,    making   the    air   puffs    for   each    tone   weaken 
periodically  the  puffs  for  the  other  tone.     The  tones  generated 
by  conditions  (i)  and  (2)  were  called  subjective;  those  by 
condition  (3),  objective.     Helmholtz  did  not  seem  to  regard 
case  (3)  as  a  condition  of  disturbed  superposition  as  demanded 
by  his  mathematical  explanation  based  upon  vibrations  'so 
large  that  the  square  of  the  displacements  has  a  sensible  influence 
on  the  motions';3  for  he  states  explicitly  of  this  case  that  he 
will  'draw  attention  to  a  third  case,  where  combinational 
tones  may  also  arise  from  infinitely  small  vibrations.^     This 
is  of  course  an  error.     Helmholtz  admitted  that  in  conditions 
favoring  objective  combination  tones  conditions  (i)  and  (2) 
were  also  operative,  thus  making  all  audible  objective  com- 
bination tones  also  largely  l subjective.'5     I  have  suggested6 
that  conditions  (2)  and  (3)  are  practically  identical  physically 

1  Read  before  the  Utah  Academy  of  Sciences,  April  3,  1915. 

2  'Sensations  of  Tone,'  p.  158. 

3  Ibid.,  Appendix  XII.,  412. 

4  Ibid.,  419.     Italics  mine. 

5  Ibid.,  157. 

6  'Combination  Tones,'  etc.,  PSYCHOLOGICAL  REVIEW  MONOGRAPH,  No.  39,  1908, 
17  ff.,  103  ff. 

512 


COMBINATION  TONES  5*3 

both  being  dependent  upon  the  principle  of  disturbed  super- 
position of  vibrations;  that  such  superposition  is  in  all 
probability  in  case  (2)  most  pronounced  in  the  liquids  of  the 
inner  ear.  This  view  has  subsequently  been  supported  by 
Clemens  Schaefer.1 

The  view  of  Helmholtz,  expressed  under  case  (i)  above, 
has  not  been  substantiated  by  recent  research.  My  own 
experiments  lend  support  to  the  conclusion  of  Helmholtz 
respecting  objective  combination  tones,  that  they  are  in 
large  part  'subjective,'  i.  e.,  that  they  are  in  a  considerable 
measure  due  to  disturbed  superposition  of  vibrations  of  the 
primaries  within  the  ear  itself. 

As  to  the  nature  of  higher  orders  of  combination  tones  two 
contradictory  views  were  expressed  by  Helmholtz.  One  was 
that  they  are  higher  order  difference  tones  in  the  sense 
suggested  by  Hallstrom,  that  they  originate  from  a  first 
difference  tone  and  a  primary  tone  or  from  two  difference 
tones.2  His  other  view  was  that  all  higher  order  combination 
tones  take  origin  directly  from  the  primaries.  This  is  in 
agreement  with  a  theory  developed  mathematically  in  1881 
by  R.  H.  M.  Bosanquet,3  and  more  recently  by  Clemens 
Schaefer  in  the  article  referred  to  in  a  preceding  paragraph. 
This  view  that  so-called  higher  order  combination  tones  take 
their  origin  directly  from  the  primaries  is  also  supported  by 
the  experimental  results  of  a  number  of  recent  investigators. 
From  the  method  of  his  statement  of  the  laws  of  the  occur- 
rence of  difference  tones,  Krueger  has  been  interpreted  by 
some  writers  to  favor  the  Hallstrom  view  of  'higher  order' 
combination  tones.  This  interpretation,  which  Krueger 
assured  me  personally  in  a  conversation4  is  wrong,  is  used  by 
R.  M.  Ogden  as  evidence  against  Krueger's  theory  of  con- 
sonance. Ogden  writes  that  "Stumpf's  investigations  in- 
dicate that  combination  tones  are  always  directly  derived 
from  the  objective  tones,  and  not  from  beats,  nor,  except  in 
the  highest  ranges  of  the  scale,  from  one  another  as  Krueger 

*  Annalen  der  Physik,  Bd.  33,  1910,  1216-1226. 

2  'Sensations  of  Tone,'  p.  154. 

8  Phil.  Mag.,  5th  Series,  XL,  1881. 

4  At  Cleveland,  Ohio,  December,  1912. 


5H  JOSEPH  PETERSON 

maintains."1  This  is  an  unfortunate  mistake  as  to  Krueger's 
view,  and,  as  I  hope  to  show  in  another  place,  the  actual  facts 
really  support  rather  than  refute  his  theory  of  consonance. 
As  to  the  facts,  I  am  willing  to  go  farther  than  either  Stumpf 
or  Ogden  and  assert  that  there  is  no  satisfactory  evidence  in 
existence  to  support  the  view  quoted  above,  that  'in  the 
highest  ranges  of  the  scale'  combination  tones  may  originate 
from  other  combination  tones.  This  is  a  matter  of  importance 
in  relation  to  theories  of  consonance. 

Though  Stumpf  quotes  approvingly  my  own  view  as  to 
the  so-called  higher  order  combination  tones,  and  seems  to 
accept  and  to  use  my  experimental  evidence,  he  registers  his 
unwillingness  to  dispute  so  generally  as  I  have  done  the 
possibility  of  difference  tones  being  derived  from  overtones 
of  the  primaries.2  No  evidence  is  offered  for  such  difference 
tones  except  that  Stumpf  has  perceived,  as  other  investigators 
have  perceived,  difference  tones  lying  in  pitch  between  the 
primaries.  Such  tones  are,  of  course,  easily  accounted  for 
on  the  theory  of  direct  origin  from  the  primary  tones  on  the 
basis  of  disturbed  superposition;  but  the  fact  of  their  existence 
is  contradictory  to  theories  like  that  of  Max  Meyer.  Riicker 
and  Edser3  established  the  existence  of  objective  intermediate 
difference  tones,  and  similar  'subjective'  tones  are  to  be 
expected  on  the  view  that  disturbed  superposition  is  the  cause 
of  all  combination  tones. 

While  Helmholtz  held  to  the  position  maintained  by 
Stumpf  as  to  the  derivation  of  certain  difference  tones  from 
upper  partials,  experimental  evidence  indicates  that  few 
difference  tones,  if  any  at  all,  have  such  origin.  Though  the 
possibility  of  such  tones  is  not  disputed  by  theory — for  these 
tones  would  follow  the  same  laws  as  combination  tones  from 
the  primaries — there  is,  so  far  as  I  know,  no  evidence  at  all 
to  indicate  that  audible  difference  tones  derived  from  upper 
partials  exist.  This  is  not  incomprehensible  when  one  takes 
into  consideration  the  fact  that  the  overtones  of  the  primaries 

1  In  a  review  of  Stumpf  in  Psychol.  Bui.,  9,  1912,  117. 

2  Stumpf,  C.,  '  Beobachtungen  iiber  Kombinationstone,'  Zeit.  f.  Psych.,  55,  1910, 
iff. 

8  'Objective  Reality  of  Combination  Tones,'  Phil.  Mag.,  5th  Series,  39,  1895. 


COMBINATION  TONES  5J5 

are  themselves  to  a  considerable  extent  ' subjective,'  or  de- 
pendent upon  periodicities  arising  in  the  liquids  of  the  inner 
ear. 

In  the  case  of  the  second  difference  tone,  D2,  which  is 
easily  perceptible  with  a  number  of  intervals,  is  there  any 
evidence  that  it  can  be  generated  by  the  higher  primary  tone 
and  the  second  partial  of  the  lower  primary,  as  suggested  by 
the  formula  D2  =  2,1  —  &?  In  the  psychological  laboratory 
of  the  University  of  Chicago  the  resonated  forks  Ut4  :  Mi4 
(4  :  5)  give  an  exceptionally  prominent  second  difference 
tone,  3,  on  very  gentle  sounding,  i.  e.,  at  an  intensity  of  the 
primaries  which  leaves  the  first  difference  tone,  DI,  entirely 
inaudible.1  D2  can  evidently  not  arise  from  the  first  difference 
tone  and  the  lower  primary.  On  substituting  Ut5  for  Ut4 — 
sounding  gently  Uts  with  Mi4 — one  should  make  the  tone  D2 
even  more  prominent,  if  it  depends  upon  the  tone  correspond- 
ing to  Ut6,  by  the  formula  4-2  —  5  =  3.  But  with  such 
substitution  a  much  greater  intensity  of  the  primaries  is 
required  to  make  D2  (3),  now  DI,  audible  at  all.  The  first 
upper  partial  of  piano  tones  in  the  middle  of  the  register  is 
easily  perceptible  even  to  the  unaided  ear — as  are  several 
others  of  the  higher  partials.  In  the  case  of  the  major  third 
(4  : 5)  with  the  following  tones  c2  :  e2,  b2:  e[?2,  and  d2  :  ^  the 
respective  second  difference  tones  at  approximately  the  pitch 
of  g1,  gl?1  and  a1  were  easily  audible,  though  the  several  first 
difference  tones  were  inaudible.  But  when  the  octave  of 
the  lower  tone  in  each  pair  was  substituted  for  this  tone  (i.  e., 
c3  for  c2,  b3  for  b2,  d3  for  d2)  the  difference  tone  in  question  in  each 
case  became  inaudible  even  though  the  intensity  of  the 
primaries  remained  the  same  as  before  the  substitution,  or 
was  slightly  increased.  The  tone  in  question  was  therefore 
evidently  not  dependent  upon  the  upper  partials. 

In  the  case  of  forks  Ut4  :  Mi4  (4  :  5)  the  first  difference 

1  It  is  well  known  to  those  who  have  experimented  with  tones  that  such  things  as 
tuning  forks  have  individualities  almost  as  marked  in  certain  respects  as  those  of  persons. 
Certain  pairs  of  forks  of  the  few  sets  with  which  I  have  become  well  acquainted  give 
clear  difference  tones  while  others  of  precisely  the  same  pitch,  and  resonated  similarly, 
give  very  weak  ones  or  none  at  all.  The  absolute  pitch  of  the  primaries  is  also  an 
important  factor  in  determining  the  presence  or  absence  of  combination  tones. 


5 1 6  JOSEPH  PETERSON 

tone,  I,  is  easily  audible  when  the  forks  are  loudly  sounded. 
Is  the  second  difference  tone  dependent  upon  this  one?  The 
fork  Ut2  gives  a  tone  coincident  in  pitch  with  this  first  differ- 
ence tone  and,  on  gentle  sounding,  almost  indistinguishable 
from  it  in  timbre.  Even  though  this  is  the  case,  when  Ut2 
is  substituted  for  the  primary  Mi4,  that  is  when  the  interval 
is  represented  by  the  forks  Ut2  :  Ut4,  the  second  difference 
tone,  3,  now  made  the  first,  disappears  altogether.  This  is 
true  whether  Ut2  is  sounded  gently — to  represent  the  dif- 
ference tone  for  which  it  is  substituted — or  loudly.  It  is 
evident,  therefore,  that  the  second  difference  tone,  3,  of  the 
major  third  in  question  does  not  arise  from  the  first  with  the 
lower  primary,  by  the  formula  /  —  (h  —  /)  =  /  —  DI  =  Z)2 
or  4  —  (5  —  4)  =  4  —  i  =  3.  If  this  is  true  of  the  second 
difference  tone  it  is  also  true  of  summation  tones  if  they  are 
really  difference  tones  of  higher  orders. 

But  there  is  yet  a  better  test  available.  In  the  case  of 
summation  tones  theoretically  explained  according  to  the 
formulae 

h  +  I  =  n(h  -  /)     and     h  +  I  =  nh  -  ml 

a  conclusive  quantitative  test  is  applicable,  one,  however,  that 
was  first  worked  out  by  the  writer  only  a  few  years  ago.  In 
the  case  of  the  fifth  (2:3)  the  difference  tone  of  the  fifth 
partials  (10,  15)  coincides  with  the  summation  tone  (5).  The 
summation  tone  is  not  easy  to  hear  unless  its  origin  is  objective 
to  the  ear.  However  with  the  use  of  resonated  tuning  forks 
I  found  that  it  was  perceptible  to  the  practiced  ear  when  the 
forks  Ut3  :  Sol3,  or  Re^s  :  La(?3  were  sounded  a  little  above 
medium  intensity.  As  an  objective  check  a  number  of 
students  trained  in  experimental  psychology  were  asked  to 
select  from  among  a  number  of  high  pitched  forks  the  tones 
that  were  audible  in  addition  to  the  primaries.  With  the 
intervals  given  were  also  Fa3  :  La3  (4:5)  and  Ut3:Las 
(3  :  5).  The  fork  representing  the  summation  tone  was  in 
each  case  selected,  as  well  as  forks  representing  certain  first 
upper  partials  that  were  easily  perceptible  to  a  trained  ear. 
Occasionally  I  suggested  to  the  subject  a  wrong  fork,  but  it 


COMBINATION  TONES  517 

was  in  every  case  rejected  finally.  One  of  the  subjects  readily 
sang  the  note  representing  the  summation  tone.  There  could 
be  no  doubt  as  to  the  existence  of  the  tone  in  question. 

By  tuning  an  auxiliary  tone  to  very  nearly  the  pitch  of 
these  summation  tones  well-marked  beats  were  obtained. 
The  auxiliary  tone  is  generated  by  an  unresonated  fork 
sounded  gently  and  held  close  to  the  ear.  After  the  auxiliary 
tone  is  exactly  tuned  to  the  pitch  of  the  summation  tone,  any 
change  in  pitch  of  the  primaries  is  at  once  noted  by  a  beating 
between  the  auxiliary  and  the  summation  tone.  On  this 
principle  it  was  found  possible  to  determine  the  true  nature 
of  the  latter.  Take,  for  instance,  the  fifth.  The  primary 
tones  and  their  respective  upper  partials  are  represented  by 
the  following  numbers: 

2,  4,  6,     8,  10,  etc. 

3,  6,  9,  12,  15, 

Now  it  is  evident  that  if  the  tone  in  question  is  a  true  sum- 
mation tone,  lowering  one  of  the  primaries  one  beat  per  second 
will  also  lower  it  one  beat.  But  if  it  is  really  a  difference  tone 
it  will  in  this  case  take  origin  from  the  fifth  partials  of  the 
primaries,  i.  e.,  from  10  and  15.  In  such  a  case  lowering  one 
of  the  primaries  one  beat  will  lower  or  raise  the  tone  in 
question  five  beats  per  second.  But  in  the  practical  working 
out  of  this  test  a  difficulty  was  encountered.  Lowering  the 
pitch  of  a  primary  tone  makes  the  interval  imperfect,  and  the 
beats  of  interference  prevent  a  careful  study  of  the  summation 
tone  with  the  auxiliary.  To  get  rid  of  these  irrelevant  beats 
the  following  procedure  was  adopted:  After  depressing  one 
of  the  primaries  one  vibration  per  second,  the  auxiliary 
fork  was  attuned  to  the  summation  tone,  a  change  that  could 
be  accomplished  with  certainty.  The  primary  tone  was  then 
brought  back  to  its  true  pitch.  The  only  beats  then  re- 
maining were  those  due  to  the  interference  of  the  auxiliary 
with  the  summation  tone.  The  demonstration  was  convinc- 
ing; there  was  absolutely  no  trace  of  rapid  beats,  but  slow 
beats  with  a  rate  of  one  per  second  were  heard.  If  these 
beats  were  due  to  interference  between  a  difference  tone  of 


5 1 8  JOSEPH  PETERSON 

the  auxiliary  and  a  primary  with  the  other  primary,  as  might 
be  argued,  one  should  hear  also  rapid  beats  of  the  auxiliary 
with  this  high  tone,  if  the  latter  originated  from  the  upper 
partials.  It  will  be  remembered  that  only  such  summation 
tones  as  were  audible  were  used  in  the  test.  Besides,  rapid 
beats  of  five  per  second  are  more  easily  perceptible  than  slow 
ones  of  one  per  second.  No  such  beats,  however,  were  audible, 
and  the  auxiliary  was  so  weak  that  no  difference  tones  were 
probably  generated;  certainly  none  was  perceptible.  The 
summation  tones  tested  were  consequently  not  explicable  as 
difference  tones  of  upper  partials,  but  were  real  summation 
tones  in  the  Helmholtzian  sense.  These  experiments,  then, 
all  contradict  the  view  that  combination  tones  may  originate 
from  upper  partials.  While  they  do  not  show  the  absolute 
impossibility  of  such  origin,  we  must  remember  that  no  case 
to  prove  the  derivation  or  combination  tones  from  upper 
partials  exists,  and  that  all  the  audible  overtones  of  musical 
intervals  are  likely  to  a  considerable  extent  intra-aural  in 
origin. 


XXIII.     PRACTICE  IN  GRADING  AND  IDENTIFYING 
SHADES  OF  GRAY 

BY  WARNER  BROWN 

The  following  report  consists  of  two  parts.  The  first 
part  deals  with  the  effects  of  practice  in  grading  during  ten 
sittings  in  which  an  attempt  was  made  to  arrange  fifty  gray 
cards  in  the  order  of  their  apparent  brightness.  No  cor- 
rections were  made.  The  result  shows  that  there  was  no 
improvement  in  the  accuracy  of  the  arrangement.  The 
second  part,  on  the  other  hand,  shows  that  in  the  course  of 
the  ten  sittings  there  was  a  substantial  improvement  in  the 
ability  to  remember  and  recognize  four  of  the  fifty  cards. 

i.     PRACTICE  IN  GRADING 

The  experiment  was  performed  twice  a  week  for  five 
weeks.  Each  worker  was  provided  with  two  sets  of  fifty 
cards  2.5  cm.  wide  and  6.5  cm.  high.  The  cards  were  covered 
with  gray  paper  ranging  from  nearly  white  to  nearly  black. 
After  being  shuffled  the  cards  of  one  set  were  laid  out  by  the 
learner  in  a  row  according  to  the  following  directions: 

The  fifty  gray  cards  are  numbered  on  the  backs  according  to  an  arbitrary  system. 
You  are  to  arrange  these  cards  according  to  their  apparent  brightness,  with  the  lightest 
on  the  left,  the  darkest  on  the  right,  and  the  others  graded  in  between.  Do  not  take 
more  than  15  minutes  for  this  part  of  the  experiment.  After  you  have  arranged  the 
cards  write  down,  in  the  table  below,  the  numbers  on  the  backs  of  the  cards  in  order. 

These  directions  were  printed  on  a  record-blank  which 
also  contained  the  table  with  fifty  spaces  for  entering  the 
numbers  found  on  the  cards.  A  fresh  copy  of  the  blank  was 
supplied  to  the  worker  at  each  practice  sitting.  Emphasis 
was  laid  on  the  fact  that  the  numbers  on  the  backs  of  the 
cards  were  unreliable  and  that  there  was  no  such  thing  as  a 
standard  arrangement  of  the  cards;  but  at  the  same  time  it 
was  confidently  asserted  that  a  good  record  in  the  later  part 
of  the  experiment  (to  be  described  shortly),  depended  upon 
a  scrupulously  careful  arrangement  of  the  cards  in  order  of 


520  WARNER  BROWN 

brightness,  for  the  amount  of  error  in  the  memory  and  recog- 
nition test  was  to  be  measured  in  terms  of  the  worker's  own 
scale  of  brightness,  and  any  irregularities  in  the  scale  would 
tend  to  increase  the  score  of  his  errors. 

In  order  to  determine  whether  any  improvement  in  the 
accuracy  of  the  arrangement  resulted  from  practice  it  was 
necessary  to  discover  the  correct  arrangement  of  the  cards. 
As  the  cards  differ  considerably  in  color  and  in  character  of 
surface  it  was  thought  that  an  empirical  determination  of 
the  correct  order  would  be  preferable  to  a  physical  measure- 
ment of  brightness  in  which  these  disturbing  factors  would 
escape  consideration.1 

The  empirical  determination  of  the  order  of  brightness  of 
the  cards  was  made  from  the  records  of  37  persons.  As 
each  worker  had  made  10  arrangements  there  were  370  judg- 
ments upon  which  to  base  the  average  position  of  each  card. 
The  data  from  this  computation  are  presented  in  Table  I. 
This  table  shows  not  only  the  average  position  assigned  to  each 
card  (with  the  mean  variation)  but  also,  under  the  heading 
"most  probable  position,"  the  position  which  each  card  would 
occupy  in  a  series  of  fifty  if  they  were  arranged  as  nearly  as 
possible  in  order  in  a  single  series  according  to  the  average 
judgment.  This  last  arrangement  takes  account  of  the  fact 
that  while  some  of  the  cards  have  almost  the  same  average 
position  they  can  not  occupy  the  same  position  in  an  actual 
arrangement. 

When  the  correct  position  for  any  particular  shade  has 
been  determined  it  is  possible  to  measure  the  accuracy  of  the 
arrangement  for  any  of  the  ten  practice  sittings  by  the  amount 
of  the  average  deviation  of  the  different  persons  from  that 

1  The  cards  used  in  this  experiment  were  prepared  from  a  set  of  'Hering'  gray 
papers.  The  numbers  given  in  the  first  column  of  Table  I.  are  those  found  stamped  on 
the  original  rolls,  but  it  is  evident  from  the  data  of  Table  I.  that  many  of  these  numbers 
are  without  meaning,  either  because  they  fail  to  designate  the  approximate  position  in 
the  series  (compare  No.  20,  No.  25,  or  No.  31),  or  because  different  numbers  are 
assigned  to  papers  of  almost  the  same  brightness  (compare  Nos.  20  and  28,  or  Nos.  25 
and  32).  Enquiry  elicited  the  information  from  the  manufacturers  that  they  made 
up  different  shades  at  different  times,  according  to  the  demand,  and  that  the  different 
batches  were  not  alike,  so  that  when  they  sold  an  entire  set  the  purchaser  received 
portions  of  different  and  dissimilar  sets. 


IDENTIFYING  SHADES  OF  GRAY 

TABLE  I 


521 


Arbitrary  Number  to 
Designate  the  Shade1 

Average  Position 

Mean  Variation 

Most  Probable  Position 

I 

1.  00 

O.OO 

I 

2 

2.00 

O.OO 

2 

3 

3.00 

0.00 

3 

4 

4.06 

0.12 

4 

5 

5-21 

0.37 

5 

6 

5.76 

0.39 

6 

7 

6.97 

0.08 

7 

8 

8.00 

O.02 

8 

9 

9-39 

0.48 

9 

ii 

10.27 

0.78 

10 

10 

n-45 

1.04 

ii 

12 

11.71 

0.95 

12 

13 

13.10 

0.85 

13 

14 

13.16 

0.83 

M 

15 

I5-56 

0.87 

15 

17 

17.49 

i-4S 

16 

16 

17.64 

i-53 

17 

18 

17.84 

1.42 

18 

19 

18.39 

1.56 

19 

23 

26.82 

20 

21 

21-35 

1.66 

21 

24 

21.47 

i-73 

22 

22 

21.86 

23 

20 

25.24 

i.'86 

24 

28 

25-36 

1.63 

25 

29 

26.26 

1.77 

26 

27 

26.67 

1.51 

27 

30 

27.29 

1.70 

28 

33 

29.46 

1.52 

29 

26 

30.04 

1.72 

30 

32 

30.42 

1-37 

31 

25 

30.60 

1.52 

32 

35 

34-35 

1-43 

33 

37 

34-59 

1.53 

34 

34 

35-64 

i.  60 

35 

39 

35.96 

1.52 

36 

40 

36.40 

i-75 

37 

36 

37-66 

1.41 

38 

31 

38.23 

1.74 

39 

38 

38.70 

1.  21 

40 

45 

42.09 

I.2I 

41 

43 

42.86 

0.96 

42 

44 

42.90 

1.  12 

43 

41 

43.04 

1.18 

44 

42 

44-75 

1.04 

45 

48 

46.02 

0.80 

46 

47 

46.56 

o.SS 

47 

46 

47-79 

o.39 

48 

49 

49.00 

O.IO 

49 

50 

49-94 

O.II 

So 

position.     A  larger  deviation  means  a  larger  number  of  cards 
wrongly  placed.     Table  II.  shows  the  average  deviation  for 
each  of  the  ten  days  of  practice.     Fewer  cards  were  wrongly 
1  See  foot-note  on  preceding  page. 


522  WARNER  BROWN 

placed  the  first  day  than  any  other  day.  There  is  not  the 
slightest  tendency  to  reduce  the  number  of  misplaced  cards 
as  practice  advances.  These  conclusions  are  the  same  whether 
the  deviations  are  calculated  from  the  average  positions  or 
from  the  'most  probable  positions'  as  defined  above.  Prac- 
tice does  not  increase  the  accuracy  of  the  work  of  grading  the 
shades  of  gray. 

TABLE  II 

THE  AMOUNT  OF  INACCURACY  IN  GRADING  THE  50  GRAY  CARDS  ON  EACH  OF  10  TRIALS 
The  average  amount  of  displacement  from  the  true  position  has  been  calculated  for 
37  persons  for  each  of  the  50  cards.     The  50  figures  so  obtained  have  been  averaged 
to  give  the  figures  in  the  table. 

Av.  Deviation  from  the 

Av.  Position  of  the          Av.  Deviation  from  the 
Card;  All  Cards  Most  Probable  Position 

Trial  Combined  All  Cards  Combined 

1  0.95  0.93 

2  1.04  I.O3 

3  1.08  .10 

4  1-13  -13 

5  i. ii  .11 

6  1.04  .04 

7  i. ii  .12 

8  1.06  1.07 

9  i. 08  i. 08 
10  i.  06  1.07 

2.  MEMORY  TRAINING  WITH  SHADES  OF  GRAY 
Most  experiments  intended  to  demonstrate  an  improve- 
ment of  memory  with  practice  require  so  much  time  and  such 
an  unusual  amount  of  patience  that  they  can  not  be  made  use 
of  in  connection  with  an  ordinary  course  of  laboratory  ex- 
periments. The  present  experiment  shows  a  very  sub- 
stantial improvement  of  memory,  or  at  least  a  form  of  memory, 
in  the  course  of  no  more  than  five  hours  of  actual  work  and 
with  very  little  of  the  effort  usually  involved  in  learning. 
The  portion  of  the  printed  directions  dealing  with  the  test  of 
memory  is  given  herewith;  the  conditions  of  work  will  be  made 
more  clear  in  what  follows. 

According  to  the  program  for  each  day's  work,  given  below,  pick  out  four  cards 
from  the  series  as  you  have  arranged  it,  and  observe  them  carefully,  without  looking 
at  the  numbers  on  the  backs  of  the  cards.  Put  the  first  set  of  cards  away.  Spread  out 
the  other  set,  face  up,  on  the  table.  Pick  out  the  same  four  shades,  as  nearly  as  you 
can,  from  this  second  set.  Mark  in  the  table  the  numbers  found  on  the  backs  of  these 
four  cards. 


IDENTIFYING  SHADES  OF  GRAY  523 

PROGRAM 

First  day.  Pick  out  the  loth,  2Oth,  3Oth,  and  4<Dth. 

Second  day.  "    nth,  2ist,  3ist,  and  4ist. 

Third  day.  "     9th,  iQth,  29th,  and  39th. 

Fourth  day.  "    I2th,  22d,   32d,    and  42d. 

Fifth  day.  "      8th,  i8th,  28th,  and  38th. 

Sixth  day.  "    I3th,  23d,    33d,  and  43d. 

Seventh  day.  "      7th,  lyth,  27th,  and  37th. 

Eighth  day.  "    I4th,  24th,  34th,  and  44th. 

Ninth  day.  "     6th,  i6th,  26th,  and  36th. 

Tenth  day.  "    loth,  2Oth,  3Oth,  and  4Oth. 

The  record  of  the  day's  work,   when  filled  out,  shows: 

(1)  the  actual  series  of  grays  as  arranged  by  the  student; 

(2)  the  four  shades   selected  by  him  in  the  memory  test; 

(3)  the  amount  of  his  error  for  each  shade.     The  amount  of 
the  error  depends  upon  the  worker's  own  arrangement  of 
the  cards.     Suppose  he  has  sought  for  the  loth,  2Oth,  3Oth,  and 
4<Dth  cards,  and  that  the  shades  which  he  has  picked  out  in 
the  memory  test,  as  they  lay  scattered  in  irregular  order  on 
the  table,  are  the  nth,  2Oth,  33d  and  39th,  according  to  his 
own  arrangement  as  shown  in  his  record  and  regardless  of  the 
true  brightness  or  arbitrary  designations  of  the  cards;  the 
errors  in  this  case  would  be  plus  one,  zero,  plus  three  and  minus 
one,  or  disregarding  the  direction  of  error,  a  total  of  five. 
The  worker  was  informed  at  once  of  the  actual  numerical 
amount  of  his  errors,  but  he  was  not  allowed  to  look  again 
at  the  cards  themselves.     It  will  have  been  observed  that 
different  shades  were  used  for  the  tests  on  different  days  so 
that  the  practice  did  not  consist  of  learning  to  recognize 
certain  shades  but  was  confined  to  the  more  general  process 
of  learning  to  perform  the  mental  operation  of  recognizing 
this  kind  of  thing. 

The  actual  amount  of  improvement  in  the  memory  test 
was  large.  Table  III.  shows  the  work  of  three  seasons.  In 
1911  the  recognition  test  was  made  with  the  same  set  of  cards 
that  was  used  in  the  memorizing  by  simply  shuffling  them  up. 
This  involved  the  difficulty  that  if  there  were  any  spots  or 
other  marks  on  the  cards  studied  they  might  help  in  the  work 
of  picking  out.  As  the  cards  suffer  considerably  from  wear 


5^4 


WARNER  BROWN 
TABLE  III 


THE  DAILY  AMOUNT  OF  ERROR  IN  RECOGNIZING  4  SHADES  OF  GRAY  OUT  OF  A  SET 

OF  50 

The  figure  is  the  average  per  person  of  the  difference  between  the  position-numbers 
of  the  4  shades  which  were  selected  and  the  position-numbers  of  the  4  shades  which 
were  sought  and  should  have  been  selected.  The  amount  of  error  decreases  with 
practice. 


Trial 

1911, 

33  Persons 

'913. 

37  Persons 

i9I3, 
Errors  on 
Probable'  Scale 

1914. 

22  Persons 

I 

IS-5 

I4.8 

14.9 

14.2 

2 

134 

I6.4 

I6.3 

"•3 

3 

12.7 

n.8 

12.8 

9.9 

4 

8.3 

12.3 

12.2 

9.6 

I 

9.1 

8.2 

9.6 
n.6 

IO.O 
II.  I 

7-5 
9.9 

I 

8.2 

9.5 

10.5 
8.6 

II.4 
9.0 

6.4 
9.8 

9 

5-9 

8.2 

8.2 

8.3 

10 

5.8 

9.0 

9.9 

IO.O 

during  the  practice  such  spots  multiply,  and  better  records 
can  be  made  with  their  help  at  the  end  of  the  period  of 
practice  than  at  the  beginning.  None  of  the  students  of  the 
1911  group  realized  that  he  was  making  much  use  of  these 
marks  but  the  result  shows  that  this  group  made  a  larger  ap- 
parent improvement  than  the  latter  group  who  were  deprived 
of  this  help  by  being  required  to  select  the  cards  from  another 
set.  In  1913  this  source  of  error  was  eliminated.  The  subject 
scattered  the  cards  of  a  second  set  and  selected  from  among 
them  according  to  the  directions  which  have  been  reproduced 
above. 

The  experiment  of  1914  was  designed  to  eliminate  anothe 
possible  source  of  error.  It  was  felt  by  many  of  the  worker 
that  the  familiarity  with  the  cards  which  was  acquired  in  the 
course  of  arranging  them  in  order  of  brightness  might  be 
responsible  for  a  large  amount  of  the  apparent  improvement 
of  memory.  Accordingly  the  experiment  was  so  arranged  as 
to  reduce  the  amount  of  this  factor  to  a  minimum.  On  the 
first  day  the  procedure  was  the  same  as  in  the  preceding  season 
in  order  that  the  first  test  of  memory  might  be  made  under 
exactly  the  same  conditions,  but  after  the  first  day  there  was 
no  arranging  of  the  cards  in  order  by  degrees  of  brightness. 


IDENTIFYING  SHADES  OF  GRAY  535 

Instead,  the  cards  were  arranged  by  the  subject  according  to 
number  with  their  faces  down  (they  were  numbered  according 
to  the  'most  probable  order'  described  above),  then  the  whole 
set  was  turned  over  and  the  four  cards  for  the  memory  test 
were  selected.  The  worker  then  preceded  to  scatter  another 
set  and  pick  out  the  cards  which  seemed  to  be  the  same,  just 
as  in  the  experiment  of  the  year  before.  The  experiment  was 
identical  with  the  one  of  the  year  before  in  every  respect 
except  that  the  workers  were  not  familiarized  with  the  material 
through  practice  in  arranging  it.  Precisely  the  same  op- 
portunities were  afforded  in  1914  as  in  1913  for  the  employ- 
ment of  special  devices,  illegitimate  as  well  as  legitimate,  as 
helps  in  choosing  the  shades.1 

The  scoring  in  1914  was  on  the  basis  of  the  average  of 
previous  determinations  as  shown  in  Table  I.  under  the  head- 
ing 'most  probable  position.'  In  order  to  make  a  comparison 
possible  between  these  results  and  those  of  1913  the  latter 
were  rescored  on  the  same  basis;  that  is  to  say,  the  error  was 
stated  in  both  cases  as  the  difference  in  position  between  the 
card  sought  and  the  card  found  if  they  were  all  arranged  in 
the  'most  probable'  order.  The  results  obtained  for  the  1913 
experiment  according  to  this  method  of  scoring  are  not  es- 
sentially different  from  those  obtained  when  the  scoring  was 
done  on  the  basis  of  the  worker's  own  arrangement  for  the 
day,  and  are  only  a  little  more  regular. 

The  improvement  of  recognition  through  practice  is  no 
less  rapid  in  1914,  without  the  additional  familiarity  which 
comes  from  arranging  the  cards  in  order,  than  in  1913  when 
this  factor  was  fully  operative.  With  this  assurance  that  the 
factor  of  familiarity  is  of  no  great  importance,  and  with  the 
evidence  that  the  results  can  be  scored  satisfactorily  on  the 
basis  of  the  learner's  own  daily  arrangements  of  the  cards 
without  undertaking  the  laborious  process  of  measuring  the 
actual  brightness  of  the  different  ones,  this  experiment  gives 
a  simple  and  easily  workable  demonstration  of  the  improve- 
ment of  a  form  of  memory  through  practice. 

1  The  most  important  of  these  devices  is  the  estimation  of  the  distance  from  the 
end  of  the  scale  to  the  lightest  or  darkest  of  the  four  cards  to  be  memorized.  It  is 


526  WARNER  BROWN 

comparatively  easy  to  find  these  cards  by  simply  counting  up  mentally,  as  the  cards 
lie  scattered  at  random  on  the  table,  from  the  white  or  black  extreme  to  the  eighth  or 
whatever  one  is  desifed.  The  other  two  cards  are  frequently  found  by  grading  in 
between  the  two  extremes.  Only  half  as  many  errors  were  made  on  the  lightest  shades 
as  on  the  middle  ones  and  fewer  errors  occurred  on  the  darkest  shades  than  on  the 
middle  ones.  There  was  no  general  tendency  to  under-  or  over-estimate  the  shades  of 
gray  in  the  memory  test,  but  too  light  a  shade  was  selected  for  the  lightest  and  too  dark 
a  shade  for  the  darkest,  and  the  same  tendency  appeared  with  the  other  two  shades,  as 
may  be  seen  from  the  following  tabulation  of  the  average  number  of  errors  per  card. 

'Too  Light  Too  Dark 

Lightest  card 1.08  0.77 

Second  card 1.90  1.57 

Third  card 1.72  l.8o 

Darkest  card 1.17  1.52 

Average  all  four  cards 147  1.42 


BF 

1 

P7 
v.22 


Psychological  review 


PLEASE  DO  NOT  REMOVE 
CARDS  OR  SLIPS  FROM  THIS  POCKET 

UNIVERSITY  OF  TORONTO  LIBRARY