Abstract

This study investigated the interaction effect of hostility and social support on CVR in a provocative experimental situation and tested the two models of social support (Cohen & Syme, 1985) by manipulating the stress level with task difficulty. One hundred and twelve male college students who scored high or low on the cynicism score of MMPI Ho scale were randomly assigned to one of two social support (support vs. no support) and one of two task difficulty (high vs. low) conditions. They were confronted by a provocative confederate during their task performance. CVR was measured every minute by systolic (SBP) and diastolic (DBP) blood pressures and pulse rate (PR) over baseline, provocative stress, and recovery periods. For low-hostility participants, the supported group exhibited significantly smaller increases in DBP than the nonsupported group during the provocative stress period. The opposite effect on SBP was observed for high-hostility men. An unexpected finding was that low-hostility men compared with high-hostility men exhibited more exaggerated SBP and DBP when they were not supported. Whereas the nonsupported group in the high-difficulty condition exhibited more increased SBP and PR during the stress period than the nonsupported group in the low-difficulty condition, there was no difference between the two difficulty conditions in terms of CVR for the supported group. During the recovery period, the supported subjects were recovered more quickly in SBP than the nonsupported, regardless of their level of hostility and the task difficulty they had been exposed to. This study provides an experimental evidence of the potential cardiovascular benefit of social support moderated by hostile attitude, and supports two models of social support. It also showed that high-hostility people do not always show more heightened CVR in response to experimental stress, for which a possible explanation (i.e., low voluntary commitment) was provided.