Traits, cognitive processes and adaptation: An elegy for Hans Eysenck's personality theory

Hans Eysenck's personality theory has inspired several generations of researchers. However, it has substantial limitations as an account of the individual differences in performance and cognitive processing associated with personality traits. Three particular areas of concern are its handling of the complexity of processing, its attribution of performance effects to variation in cortical arousal, and its neglect of the adaptive significance of traits. The neurological concomitants of traits may be more consequential as indirect influences on skill acquisition than as direct influences on adaptation. Cognitive-adaptive theory provides a contrary perspective that sees traits as distributed across multiple processes and accommodates the dynamic nature of individual differences in adaptation. It may be time to laud the Eysenck theory for its historical contribution and lay it to rest with due respect.