Individual differences in the orienting response: nonresponding in nonclinical samples.

The complete failure of the electrodermal orienting response (OR), although widely studied in clinical samples, has received little systematic attention in work with healthy adults. The published studies of nonresponding using nonclinical samples are reviewed, with data from three unpublished studies pertinent to the question, to identify the characteristics of nonresponders. The most durable findings to date are that nonresponding shows both trait and state characteristics, and that nonresponders are more likely to be female than male, to show hypoarousal in the electrodermal system but not complete unresponsiveness in this system or low arousal in other systems, and to show higher scores on measures of impulsiveness and antisociality but not to differ from responders in terms of sensation seeking. Most of these data can be reconciled with two different accounts of the OR mechanism. One is that proposed by I. Maltzman which postulates a difference between voluntary and involuntary ORs, and the other is that of J. A. Gray which proposes that the OR is a function of activity in a Behavioural Inhibition System. Taken together, these accounts imply that the OR reflects attentional and affective processes, and that both cognitive style and temperamental differences in the appraisal of threat can lead to electrodermal nonresponding.