HABITUATION OF THE ORIENTING RESPONSE TO MULTIPLE STIMULUS SEQUENCES.

The purpose of the study was to test the hypothesis that rate of habituation of the orienting response (OR) to multiple stimulus sequences is a negative function of the uncertainty (H) in the stimulus series. Seven groups of 30 Ss received 10 presentations of a l0 sec light stimulus (S[sub1]) followed immediately by a 1 sec 70 db auditory stimulus (S[sub2]) on 0, 10, 20, 50, 80, 90 or 100 percent of trials. The response measure was change of skin conductance to S[sub1]. Mean conductance change scores of the various groups were closely related to the degree of uncertainty (H) in the stimulus series. The results were interpreted as offering support for Sokolov's OR theory, and the view that, in human information processing, information concerning stimulus probabilities is integrated continuously to form the basis of predictive extrapolation. [ABSTRACT FROM AUTHOR]