ABSTRACT
THE statement that almost any objective measure of behaviour we care to take will inevitably reveal wide individual differences in performance is so commonplace that its reiteration here may seem scarcely necessary. Yet, in their search for general laws of behaviour, psychologists have tended to minimize the importance of such variations, feeling, no doubt, that overemphasis on them may unduly restrict the generality of the principles they have enunciated. To the personality theorist, of course, it is these very individual differences which are of central importance, since any attempt to describe, classify, or measure personality is, almost by definition, itself an exercise in the analysis of individual variations in response. Only fairly recently in the history of psychology has there been, however, a realization that a useful link can be made between personality factors and previously unexplained variations in performance on tests hitherto largely outside the immediate interest of the personality theorist. Furthermore, there is now increasing confidence that the systematic study of this link between these two approaches to behaviour analysis can become a means of furthering, rather than handicapping, the search for general psychological laws.
