Response Requirements and Directional Fractionation of Autonomic Responses

Physiological responses were monitored while 27 male S s were shown a series of 45 colored slides of homicide victims. Nine of the S s were required to simply look at each slide (Nonraters), 9 were required to push 1 of 7 buttons, after each trial to indicate how disturbing they found the slide to be (Raters). Evidence for directional fractionation of autonomic responses to the slides was obtained for only the Nonraters. Their responses included cardiac deceleration, an increase in skin conductance, digital vasoconstriction, and cephalic vasodilation. The Raters responded with cardiac acceleration, an increase in skin conductance, and both digital and cephalic vasoconstriction. The Raters also showed a larger increase in tonic skin conductance over trials than did the Nonraters. To determine whether the physiological responses of the Raters were influenced by the requirement to make a motor response, 9 other S s pressed a button after each slide. The physiological responses of these latter S s were almost identical with those of the Nonraters. The results are consistent with the hypothesis that the requirement to rate the stimuli was associated with appraisal and cognitive elaboration. They also indicate that response requirements can have a profound effect upon autonomic responsivity.