Gut feelings and the reaction to perceived inequity: The interplay between bodily responses, regulation, and perception shapes the rejection of unfair offers on the ultimatum game

It has been robustly demonstrated using the ultimatum game (UG) that individuals frequently reject unfair financial offers even if this results in a personal cost. One influential hypothesis for these rejections is that they reflect an emotional reaction to unfairness that overrides purely economic decision processes. In the present study, we examined whether the interplay between bodily responses, bodily regulation, and bodily perception ("interoception") contributes to emotionally driven rejection behavior on the UG. Offering support for bodily feedback theories, interoceptive accuracy moderated the relationship between changes in electrodermal activity to proposals and the behavioral rejection of such offers. Larger electrodermal responses to rejected relative to accepted offers predicted greater rejection in those with accurate interoception but were unrelated to rejection in those with poor interoception. Although cardiovascular responses during the offer period were unrelated to rejection rates, greater resting heart rate variability (linked to trait emotion regulation capacity) predicted reduced rejection rates of offers. These findings help clarify individual differences in reactions to perceived unfairness, support previous emotion regulation deficit accounts of rejection behavior, and suggest that the perception and regulation of bodily based emotional biasing signals ("gut feelings") partly shape financial decision making on the UG.