Individual differences and sensitivity to cues of reinforcement
Mischel (1968, 1973), challenged the trait approach to the study of individual differences by claiming that traits lacked predictive utility and that people did not display the degree of consistency pre-supposed by traits. It is suggested here that often the real difference between those who espouse the idiographic and those who espouse the nomothetic approaches is one of emphasis. It is, therefore, proposed that a theory which provides a biological basis for differential conditionability might prove to be a useful point from which to start building a theory of personality which integrates these two approaches. Two theories, Eysenck's and Gray's, initially looked promising and so predictions drawn from these were compared in a series of three conditioning experiments. No support was found for Gray's theory, and although a degree of support was found for Eysenck's theory it was concluded that this theory lacked heuristic value. People were found to condition with remarkable efficiency, however. Experiments four and five followed up some speculations as the nature of anxiety, looked at consistency both behavioural and self-rated and again put predictions drawn from Gray's theory to the test, but this time abandoning Gray's assumption that differential sensitivity to cues of reinforcement is related to the introversion-extraversion dimension, and looking at differential sensitivity as a performance variable. Evidence was found supporting Gray's speculation with respect to differential sensitivity. No evidence of behavioural consistency was found, and no support for a general factor of consistency was found when self ratings of consistency were examined. Cognitive variables did, however, appear to be important in determining behaviour. It was concluded that Eysenck' s theory was not robust enough to form the basis of the type of theory proposed here. Gray's theory needs some major modifications, especially in relation to the assumed relationship between active avoidance and appetitive reinforcement. It seems that whether or not consistency will be observed is determined by many factors, not least of which is the complex relationship between situational and cognitive variables. It is suggested that conditioning may well play an important part in determining behaviour and it might prove fruitful to follow the lead offered by Pavlov, Teplov and Nebylitsyn and move from properties of conditioning and of the nervous system to theories of personality, rather than the other way round. It is also suggested that we should be working towards a theory which explains both why, and in what ways people were different and similar, a theory which set itself the target of describing and explaining the relationships between individual abilities, conditioning and cognitive factors, such as the use made of strategies.