Why do people tend to overpredict pain? On the asymmetries between underpredictions and overpredictions of pain

After an underpredicted painful experience people tend to expect increased pain levels for a considerable time, despite disconfirmatory experiences. Underpredictions also tend to raise long-lasting fear and increased physiological responding. Overpredicted pain does not have such dramatic effects. What are the reasons for this asymmetry? Evidence for and against the hypothesis that underpredicted pain hurts more than correctly predicted pain, and that overpredictions result from a tendency to avoid the extra aversiveness of underpredictions, is reviewed. Based on recent experiments this explanation is rejected, and alternative explanations are discussed. It is reasoned that the most plausible explanation is that the organism automatically infers danger from an underprediction, because of the loss of predictability into the dangerous direction (i.e. more pain). Elevated expectancy and fear levels are the result of this. A modified stimulus-comparator model that accounts for the differential effects of both types of incorrect predictions is suggested. In contrast to previous models, such a model hypothesizes: (i) differential processing of under- and overpredictions; and (ii) different processes involved in the influence of expectations on subjective and non-subjective pain responses.