Conditioned and unconditioned cardiovascular reactivity: Predictability and stability over time

Abstract

Two aspects of cardiovascular reactivity are distinguished: Unconditioned Reactivity (UCR) on the one hand and Conditioned Reactivity (CR) on the other hand. Both aspects of reactivity were operationalized by the a priori classification of changes of discriminative cardiovascular responses (heart period, finger pulse amplitude, pulse transit time) observed in 50 Ss (40 experimental group Ss, 10 controls) during the course of a discriminative conditioning session. Ss who showed a distinct reaction to the unconditional stimulus (UCS: aversive auditory noise) in the acquisition phase as well as towards the conditional stimulus (CS+: green light) in the extinction phase were assigned to the CR type, Ss who displayed reactivity only in the actual confrontation with the UCS in acquisition to the UCR type. Two further types of reactivity with the common characteristics of low responsiveness to the UCS were defined. The reactivity types defined on the basis of their cardiovascular response patterns could be differentiated through independently obtained criteria. Both of the high reactivity types (CR and UCR) obtained higher anxiety scores (state and trait) than the low reactivity types. The CR type differed from the UCR type in slightly higher introversion scores and in higher state anxiety as well as in more distinct anticipatory cardiovascular activation, all prior to conditioning. In a follow-up study arranged as a replication of the extinction phase of the conditioning session 22 months apart in time, conditioned cardiovascular responses were still observed for Ss of the CR type. No such after-effects could be found for either Ss of the UCR type or for those of the low reactivity types. These results may be relevant for hypotheses regarding the participation of learning processes in the formation of individual differences in cardiovascular reactivity as a possible risk factor for cardiovascular disease.