Unconfounded Electrodermal Measures in Assessing the Aversiveness of Predictable and Unpredictable Shocks

The effect of temporal information on the electrodermal response to an aversive stimulus (shock) was evaluated. Eighty female volunteers were presented with trials in which the onset time of an aversive shock was either predictable or unpredictable. Following each trial, subjects indicated the degree of distress they felt while they were waiting for the shock to occur, and the perceived aversiveness of the shock at its impact. Skin resistance was recorded continuously. The responses produced by the predictable shocks were smaller than those produced by the unpredictable ones. Self‐report measures also followed this trend; more people preferred the predictable condition. Information about the timing of an aversive event appears beneficial for people both at a subjective and at an autonomic level.