Heart rate and skin conductance during experimentally induced anxiety: The effect of uncertainty about receiving a noxious stimulus.

Abstract

45 undergraduates were divided into 3 equal groups differing in expectancy for receiving an unavoidable noxious stimulus on the count of 10 in a 15-number countup. One group was told that the likelihood of receiving a shock was 5%, another 50%, and another 95%. 2 trials were presented. In the 1st, no S received a shock; in the 2nd, all Ss received a shock. For both heart rate and skin conductance, the 5% expectancy group exhibited the greatest, and the 95% group the least, arousal during the anticipatory period. On both measures, the 5% expectancy group exhibited the greatest impact effect. It is concluded that within limits, low expectancy about the occurrence of an unavoidable threatening event increases anticipatory anxiety as well as the reaction to impact. (19 ref.) (PsycINFO Database Record (c) 2016 APA, all rights reserved)