16 THE FACTORS OF THK MIND

for example, we can say that James is weak in all subjects
where verbal facility is needed, and in those subjects or that;
aspect of his subjects only, then his requirements become
much clearer than if we enumerated an unsystcmatixed and
seemingly incongruous catalogue of subjects (handwork,
drawing, writing, arithmetic, etc.) in which he does well,
and another detailed Ifst in which he does badly (reading,
spelling, composition), without being able to specify any
characters in common. And generally, if such far-reaching
qualities as good memory, good motor co-ordination, weak
visualization, poor auditory imagery, can be established as
* factors' having a fairly wide range, each entering not into
a single subject or test, but into a group of tests or subjects,
the grouping thus revealed will manifestly render both
diagnosis and treatment more speedy and more effective.

The practical value of descriptions in terms of what is
virtually a general factor (as in the awards, for example, of
the junior county scholarship examinations, or in the " LQ.J
or * mental age ? derived from tests of intelligence) is already
well appreciated : the practical value of these less general
descriptions, in terms of what are called 4 group-factors/ 5s
not so widely recognized. Yet, to my mind, it furnishes one
of the most pressing reasons for research along factorial
lines.1 What is true in educational diagnosis is equally true
in vocational diagnosis : unless group-factors can be estab-
lished, vocational guidance, except as regards the general
level of the career advised, becomes almost impracticable*
Similarly, if such * temperamentalJ factors as general
emotionality, introversion, cxtraversion, depression, and the
like can be successfully established, the diagnosis and treat-
ment of the neurotic, the psychotic, and the delinquent will
be greatly simplified.

1 This was, indeed, the pressing reason which led me to an early search
for factors other than general intelligence on the cognitive side, A were
adherence to the ' two-factor theory' (which recognizes no broad factors
except that of general ability or g, eked out by innumerable specifics) would
make educational guidance difficult and vocational guidance exceedingly
complex. The clinical examination of backward pupils,, and the beneficial
effects of specialized treatment in cases of * special disability,' strongly sug-
gested the existence^ of group-factors; and statistically controlled investi-
gations seemed requisite to verify these first-hand impressions*