ABSTRACT
EVEN if it be agreed that intelligence is a unitary function of the form that we have described, the possibility of there being, in addition, special abilities, is not necessarily precluded. The crucial problem with regard to special abilities is, “Are they determined by special psychological processes, or are they solely dependent upon differences in the material with which they deal?” There is an absolute lack of evidence for special psychological abilities. Thus Dr. Burt says:—
“Special abilities of a more elementary and strictly psychological kind have been found far harder to determine. As already observed, in supposing that definite faculties could be measured by one or two typical tests, the earlier experimenters proved to be much mistaken. The few recent inquiries that have approached the problem with the proper statistical methods—those of correlation and partial correlation—have so far been unfruitful: they have as yet succeeded in isolating no special unitary functions, much less have they succeeded in devising for such functions any specific tests.” 1
