Individual differences in habituation of human physiological responses: a review of theory, method, and findings in the study of personality correlates in non-clinical populations.

Studies up to 1976 of the relationship between psychometrically defined dimensions of personality and individual differences in habituation of EEG and autonomic responses were examined. Attention was confined to reports employing persons who were not diagnosed as suffering from mental disorder, institutionalized for this reason of for delinquent or criminal behaviour. The dimensions of extraversion and anxiety were most frequently found to be implicated in predictions about individual differences in response habituation, though no consistent rationale for these predictions was identified. Methodological problems involved in studying the predictions were considered, and a number of factors relating to measurement of personality and habituation and the experimental conditions under which response habituation is studied were suggested as possible sources of confounding. A survey of the empirical literature led to the conclusions that anxiety as defined by the Manifest Anxiety Scale is related to habituation of the finger vasomotor response but probably not to habituation of the electrodermal response, while extraversion, as defined by Eysenck's scale, is related to habituation of the electrodermal response. For other scales and other dimensions, including cognitive factors, the available data are inconsistent or too meagre to permit conclusions being drawn. It is suggested that future research be directed to a systematic investigation of the conditions under which personality factors contribute significantly to individual differences in response habituation, rather than seek to identify general relationships.