Differential Responsiveness of Two Electrodermal Indices to Psychological Stress and Performance of a Complex Cognitive Task

Sixteen high trait anxious and 16 low trait anxious male Ss were assigned to a high stress (HS) or a low stress (LS) condition and were given differentially stressful instructions. All Ss were then required to perform a complex cognitive task, the Halstead Category Test. Adjusted indices of tonic and phasic exosomatic electrodermal activity were monitored throughout the experiment. Level of tonic skin conductance (SC) was only minimally responsive to the manipulation of psychological stress but increased greatly during cognitive and perceptual activity. Phasic activity increased significantly following psychological stress but not following cognitive and perceptual activity. It was concluded that these results support a multiple component theory of electrodermal activity. Phasic electrodermal activity appears to increase with psychological as well as physical threat and was suggested to be a good index of autonomic emotional arousal. Tonic SC appears to change mainly as a function of cognitive activity.