Edens, J. L., Larkin, K. T., Abel, J. L. 1992. The effect of social support and physical touch on cardiovascular reactivity to mental stress. Psychosomatic Research 36, 371-382.

To examine the effects of social support on cardiovascular reactions to behavioral stress, the present study tested the relative contribution of three elements of social support: the presence of another person in the laboratory; the presence of a person considered to be a friend; and physical touch. Sixty undergraduate females were assigned to one of the following groups: alone (A); friend present-touch (FT); friend present-no touch (FNT); stranger present-touch (ST); and stranger present-no touch (SNT). Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) measures were obtained across baseline phases and during presentation of two behavioral challenges (mental arithmetic, mirror-tracing). The findings suggest that neither the presence of a stranger nor physical touch are related to attenuated cardiovascular reactions to stress; rather, if the extent of cardiovascular reactivity is related to social support, the presence of a friend may be the important mediating variable.