Human heart rate responses during experimentally induced anxiety.

Abstract

The present study was designed to discover some of the controlling conditions of the two cardiac effects found during anxiety induced by signals of shock-to-come. Varying instructions were given to 4 groups of male students. In all groups there was an acceleration in cardiac rate on the first shock anticipation trial. This acceleration was not a transitory effect which disappeared soon after the initial warning of forthcoming shock, although the two groups that received shock did not retain as much of the acceleration as did the two groups not receiving shock. The groups that were told when to expect the shock showed in addition a pronounced deceleration at the time shock was expected. Both acceleration and deceleration occurred in the group that never received a shock. It was speculated that these 2 cardiac effects may be unlearned responses associated with what may be called anxiety and fear. When S expects a noxious stimulus of unknown strength a state of anxiety with its associated response of cardiac acceleration is aroused, and in addition if S expects the noxious stimulus at a particular instant in time a state of fear with its associated response of cardiac deceleration is aroused immediately prior to and during the time the stimulus is expected.