Description:
ABSTRACTReduced autonomic and subjective reactions to aversive stimuli under predictable as compared to unpredictable conditions have been explained on the one hand by the mechanism of preception and on the other hand by orienting response (OR) reinstatement in the unpredictable condition, with differences in rated aversiveness not necessarily being involved. To test differential predictions based on an habituation vs. preception position, as suggested by Lykken and Tellegen, one group of male volunteers was presented with 30 trials in which the onset time of an aversive white noise tone (110dBA) was signalled, while in the other group the onset time was not signalled. A control group received unsignalled presentations of 70dBA white noise tones. Following each trial, subjects indicated the aversiveness of the white noise at its impact. SCRs were recorded continuously. Responses produced by the signalled tones decreased over trials, while responses produced by the unsignalled 110dBA tones increased over trials. The control group exhibited a continuous decrease. Self‐report measures showed an overall decrease over trials but no differential decline. It was concluded that an OR reinstatement interpretation seems to be best in line with the data, although the observed functional significance of signalling at the autonomic level needs further evaluation to arrive at a clear distinction between OR theory and the preception hypothesis.