Emotion matters: The pathways and the consequence of third-party intervention triggered by unfairness perception

Third-party intervention is an altruistic behavior of maintaining fairness at personal costs in a self-irrelevant situation. Though prosocial emotion has been considered an important trigger of altruistic behavior, how emotional involvement is related to third-party intervention during unfair events remains elusive. To address this issue, we manipulated allocation fairness and assessed emotional states before and after intervention in a third-party dictator game. Participants were assigned different intervention abilities and given three choices: punishment, compensation, or inaction. The results indicate that unfair events trigger third-party intervention by eliciting injustice-related negative emotions. Increased event unfairness led to more frequent and intense intervention, along with a preference for punishment over compensation. Moreover, choosing to intervene resulted in a significant emotional improvement compared to inaction. Individuals with stronger intervention abilities or a heightened perception of unfairness experienced greater emotional improvement following intervention. Furthermore, compensatory intervention led to greater emotional improvement than punitive intervention. In summary, the present study demonstrates a mediating role of negative emotion in the impact of unfair events on third-party intervention which, in turn, alleviates the intensity of negative emotions associated with injustice perception.