Change in Stimulus Conditions and the Orienting Response

A review of studies of the orienting response (OR) to variation in the properties of a stimulus following habituation indicates that not all human Ss respond with an OR to changes of which they are aware and that the only conditions which have been found consistently to elicit the OR are an increase in the intensity of the stimulus and change in the modality of its presentation. These findings pose problems for the theory of the OR advanced by Sokolov (1960) which makes no allowance for a failure to respond to a detectable change in stimulation and which relies for support on evidence that the OR is not elicited solely as a consequence of the activating effects of stimulation. To clarify some of these problems it is suggested that future work should investigate the effect of complete omission of the stimulus on the OR and the contribution of individual differences in physiological responsiveness and perceived significance of a change to elicitation of the OR. Copyrigh