Acute pain has the essential function of protecting organisms from harmful influences through painful signals that trigger protective behavioral responses. Chronic pain, however, has merely stress...Show moreAcute pain has the essential function of protecting organisms from harmful influences through painful signals that trigger protective behavioral responses. Chronic pain, however, has merely stress-inducing and disabling characteristics. To enable the development of treatment, understanding the mechanisms underlying pain experience is indispensable. Previous research has demonstrated how expectancy-induced nocebo effects (i.e., the worsening of a symptom caused by negative expectations) can provoke hyperalgesia, an increased sensitivity towards pain. The present study aimed to reproduce these findings and investigate the precise role of expectancies in the relationship between nocebo-inducing cues and the resulting pain experience. Within the context of expectancy, this study was further exploring the degree of awareness involved in the participants’ perception of their accuracy in predicting upcoming pain intensities. Sixty-nine healthy volunteers were divided between the experimental and the control condition, both of which received repeated electrical pain stimulation. Through verbal suggestion and conditioning, the experimental group learned to associate a specific color with high pain intensity and a second color with a medium intensity stimulus. In the control group, there were no instructions and the order of pain intensities and color cues was randomized. During the test phase, all color cues were accompanied by medium intensity pain to measure the magnitude of nocebo responses associated with the conditioned color as opposed to the control color. Pain expectancy and experience, as well as the extent to which they both matched, were measured through self-report scales after each stimulus-color pair. Nocebo conditioning produced the expected higher pain and expectancy ratings for the conditioned cue, as compared to the unconditioned cue in the nocebo group’s test data. Next, expectancies appeared to significantly mediate the effect of the nocebo-induction on pain experience in the experimental group. Finally, there was no significant indication that participants were aware of their degree of prediction accuracy. These findings confirm the significant involvement of expectation in pain experience and warrant further research on awareness in pain perception. Additional research is needed to provide deeper insight on the psychological processes underlying pain experience, as it will help optimize treatments for patients suffering from chronic pain.Show less
