Effects of Stimulus Intensity on Electrodermal Activity

Abstract

ABSTRACT The present experiment employed a between‐subjects design (N=75) to investigate the effects of auditory stimulus intensity on a number of aspects of the skin conductance response (SCR) and the skin potential response (SPR). The primary predictions were that the electrodermal orienting response (OR) would be characterized by SCRs with relatively fast recovery times and positive SPRs, while the defense response (DR) would consist of SCRs with relatively slow recovery times and negative SPRs; SCR habituation differences as a function of stimulus intensity were also expected. Subjects received 12 presentations of a 1000 Hz tone of 45, 60, 75, 90 or 105 dB. Stimulus rise time was 30 msec and the duration 2 sec. The results provided no evidence for the differentiation of electrodermal ORs and DRs, and the effects of stimulus intensity were confined largely to differences in SCR magnitude; all groups displayed SCR habituation. The data from the first trial were examined using several multivariate procedures, and these results are discussed in terms of Sokolov's (1963) distinctions between ORs and DRs and in terms of Edelberg's (1973) model of electrodermal activity.