Pain Modulates Optimism-Biased Belief Updating and Confidence

Optimism-biased belief updating-the tendency to update beliefs more strongly in response to desirable than undesirable news-is an important psychological resource for maintaining mental health. Here, we investigated whether pain modulates optimism bias and its underlying confidence-weighted belief updating. Participants exposed to topical capsaicin (pain group) or Vaseline (control group) estimated and updated the probability of positive or negative life events and rated their confidence in the estimations. Results verified the optimism bias effect and further identified an optimism-biased confidence phenomenon: confidence in first estimations negatively predicted belief updating. Furthermore, confidence in second estimates increased more significantly after receiving desirable information than undesirable information. Contrary to our hypothesis, we found no clear evidence that pain directly altered optimism-biased updating; however, pain reduced the overall increase in confidence during the updating process. These findings elucidate a nuanced role of pain in shaping optimism-biased confidence and may inform interventions that target metacognitive processes in pain management.