In chapter 1, we introduced the essentials of trait theory. We saw how personality might be characterised in terms of broad dimensions related to a variety of behaviours, including responses to personality questionnaires. We saw, too, that psychometrics provides statistical tools for identifying these dimensions, and that the use of techniques such as factor analysis has provided the beginnings of a consensus on personality structure. In this chapter, we shall discuss the unreliability of predicting behaviour for an isolated situation, in contrast to the reliable predictions we can make across many situations. We also discuss interactionism: the inter-relationships between personality traits and situations that have an impact on the expression of behaviour. Finally, we explore the cross-cultural generality of trait structure.

Traits and situations

If the aim of psychology is to explain behaviour, then personality traits succeed as constructs only insofar as they make a contribution to this end. Hence, the success of the trait approach requires that (1) individuals can be described in terms of their levels on valid and enduring dispositions, and (2) individual differences in these dispositions can predict a substantial proportion of the variance in behaviour. An alternative or complementary view, inspired by the successes of learning theory (Dollard and Miller, 1950), is that human behaviour is largely dependent on the situation. The so-called person–situation controversy derives from distinguishing two stark alternatives, that human behaviour is the result of either enduring dispositions or of the situation (Carson, 1989).