Sensory and temporal information about impending pain: the influence of predictability on pain.

Theories disagree about whether a verbal warning for pain has a detrimental or beneficial effect on the impact of an actual pain stimulus. Scheme-based theories predict a detrimental effect, whereas more representation-based, stimulus-comparator theories propose a beneficial effect. In this study, the influence of sensory predictability and temporal predictability is investigated. To control for attentional processes and to obtain a behavioral measure of the intrusive character of pain, an auditory discrimination task was introduced. This study firmly demonstrates that information about the painful nature of a heat stimulus does not a priori have detrimental effects on the impact of the stimulus. In fact, conditions in which a pain warning was given displayed a diminished impact in the SCR amplitude as well as in the subjectively reported intensity of the heat stimulus. Informing Ss about the exact time of administration did not add to the impact modulation, but instead resulted in a less-anxious state between signals. Although an overall behavioral disruption, particularly at onset, was observed, the behavioral data did not parallel the results of the two other response systems. Results are discussed in terms of scheme-based models, stimulus-comparator theories and the safety-signal hypothesis.