Abstract
Perception of injustice is considered closely related to third-party intervention, which refers to sacrificing self-interest to maintain fairness during a perpetration situation. However, the role of emotion during injustice perception and its relation with third-party intervention remains elusive. To this end, we measured individuals' emotional states in pre- and post-tests in a variant of the third-party intervention paradigm, where fairness perception and intervention ability were concurrently assessed. The results show that more unfair events prompted more frequent and intense interventions, irrespective of one’s intervention ability. Moreover, we observed that negative emotion caused by unfair events is a direct promotor of third-party intervention. Participants expressed improved emotional state after the intervention. Those with stronger intervention abilities or perceiving more unfair events received more emotional benefit from the intervention. Furthermore, compensatory intervention produced more emotional improvement than punishment intervention. In summary, the present study demonstrated the promotor role of emotional benefit in the implementation of third-party intervention, which provides a new explanation for self-sacrifice altruistic behavior.