The induction of social pessimism reduces pain responsiveness.

Objectives: Past work has found that optimism reduces a person's responsiveness to pain, but the effects of pessimism are not clear. Therefore, we gave pessimistic forecasts of participants' future social life and measured changes in their pain responsiveness. In particular, some participants were told that they would end up alone in life.

Methods: Seventy-five subjects were investigated in three conditions (negative forecast, positive forecast, no forecast) for changes in pain threshold and pain tolerance threshold. Pressure pain induction was accomplished by either human- or machine-driven algometers. A randomly assigned bogus forecast promising either a lonely or a socially satisfying future was ostensibly based on a personality questionnaire and an emotional dot-probe task. As potential covariates, questionnaires assessing dispositional optimism (LOT-R), pain catastrophizing (PCS), and self-esteem (SISE) were given.

Results: Pain thresholds suggested a change toward unresponsiveness only in the negative forecast condition, with only small differences between the modes of pain induction (i.e., human or machine). The results for pain tolerance thresholds were less clear also because of limiting stimulation intensity for safety reasons. The covariates were not associated with these changes.

Conclusions: Thus, people expecting a lonely future became moderately less responsive to pain. This numbing effect was not modulated by personality measures, neither in a protective fashion via dispositional optimism and self-esteem nor in a risk-enhancing fashion via trait pain catastrophizing. Alternative mechanisms of action should be explored in future studies.