| Abstract: | Data from an earlier study of physiological responses to affective visual stimulation were reanalyzed in an attempt to delineate the cardiovascular components of the OR and the DR. A HR response profile to unpleasant stimulation was obtained for each of 49 Ss by computing his average beat-by-beat HR response to slides of homicide victims. A hierarchical grouping procedure was then used to group these profiles in terms of similarity. An optimum grouping of three distinct groups of profiles emerged. Group A consisted of 9 Ss whose HR responses were accelerative in nature, Group D of 12 Ss who gave marked decelerative responses, and Group MD of 28 Ss who gave moderate decelerative responses. The cephalic vasomotor response given by Grup A to the homicide slides was vasoconstriction, while the response of Groups D and MD was vasodilation. The results provide some support for the suggestion that the OR consists of HR deceleration and cephalic vasodilation, while the DR consists of HR cceleration and cephalic vasoconstriction. However, it is possible that these “classic” patterns of cardiovascular activity occur in only some Ss and only under certain conditions, and that they may be obscured by the use of undifferentiated group data. |
