H2 THE FACTORS OF THE MIND

topic of controversy. In the earliest attempts 1 to verify
the existence of a general factor, the presence of additional
group-factors certainly made itself felt; but from their very
nature, their influence was bound to be relatively small, and,
in factorial work, was almost always overshadowed by the
more dominant general factor. On the other hand, in
practical work with backward and neurotic children, and in
the psychological clinic where children are referred for
special examination, and exceptional cases are no longer the
exception but the rule, there it seemed impossible to account
for the recurrent types of specialized disability, and for the
recurrent contrasts of temperament and character, unless
factors of a more limited kind were also assumed.

Nevertheless, Prof. Spearman and most of the earlier
laboratory workers could discover little convincing
evidence for such an assumption. After reviewing the chief
factorial studies of his pupils, he writes : " cases of specific
correlations or group-factors are astonishingly rare ; over
and over again they have been proved to be absent even in
circumstances when they would most confidently have been
anticipated by the nowadays prevalent a priori job analysis.
Of * special abilities'a . , . there are but the scantiest

1 For example, my first experiments on intelligence tests at Oxford showed
" a small but discernible tendency for subordinate groups of allied tests"
(e.g. sensory tests, motor tests, and memory tests) " to correlate together "
after the * general factor' had been eliminated (Brit. J. PsychoL, III, 1909,
p. 164). The study of sex-differences, and of hereditary differences generally,
particularly in the field of sensation, pointed in the same direction [22], [23],
Conclusive evidence, however, was hardly to be expected until the intro-
duction of group tests [20] allowed us to test far larger numbers and so
reduce the probable errors. Similar group-factors were subsequently demon-
strated both in emotional reactions [30] and in educational abilities [35].

2 The reference here is apparently to such factors as the e verbal or lin-
guistic factor ' and the * manual or mechanical factor,' which had been (so I
considered) demonstrated in my earlier work on educational abilities and
vocational guidance: in a recent Re-port (quoted above) I had just argued that,
in addition to the * two factors/ we seemed compelled to recognize a third,
which I there called * special abilities or group-factors " (loc. cit, sup., p. 19).
In disproof of the " assumed special ability for verbal operations," Spearman
quotes Davey's work as ' decisive.' On the other hand, he seems to accept
the " special arithmetical factor " which had been confirmed by both Rogers
and Collar, The ' mechanical factor * he believes to be explicable by
artificial training. He has, however, always urged that the phrase * special