Psychophysiologic Reactivity as a Dimension of Individual Differences

Abstract

Studies of hemodynamic and neuroendocrine reactions to behavioral stimuli comprise a substantial portion of laboratory research in cardiovascular behavioral medicine. It is widely thought that exaggerated physiologic responses to psychological challenge, or stress, may be implicated in the etiology or clinical expression of certain cardiovascular disorders, including coronary heart disease and essential hypertension (Manuck & Krantz, 1986). As described in the previous chapter, behaviorally elicited physiologic reactions vary in their magnitude and patterning, in part, as a function of the nature of the eliciting stimuli (i. e., stimulus specificity). It is also well established that individuals exposed to the same experimental stimulus exhibit marked variability in cardiovascular and neuroendocrine responses. The present chapter addresses several issues relating to the latter phenomenon, individual differences in psychophysiologic reactivity. Considered specifically are three attributes of individual differences that have significance for current hypotheses linking cardiovascular and neuroendocrine reactivity to aspects of cardiovascular disease: (1) the temporal stability of individual differences in psychophysiologic reactivity; (2) the reproducibility of these individual differences under varying stimulus conditions; and (3) the generalization of individual differences in physiologic responses from laboratory evaluations to measurements obtained in field (or natural) settings. Consideration of these issues is preceded by a discussion of common aspects of protocols used in psychophysiologic assessment, as well as of related matters regarding the quantitative expression of individual differences in reactivity.