Keeping Words Outweighs Keeping Fair: Third-Party Pun-ishment Prioritizes Dishonesty over Unfairness

Third-party punishment is crucial in maintaining social norms. Previous research primarily focused on the effects of violating one single norm, often neglecting the scenario where multiple norms coexist, let alone understanding whether different norm violations are of the same priority in third-party punishment. To answer this question, this study introduced scenarios in which one norm was breached while another was upheld and generalized the findings to both directions of norm violation, i.e., self-serving and altruistic. Utilizing a modified Trust Game paradigm, participants were made to observe interactions between trustees and trustors, manipulating both honesty (the alignment between proposed and actual distributions) and fairness (the outcomes of distributions). The results demonstrated that in the self-serving and altruistic directions, scenarios featuring fairness yet violating honesty elicited harsher punishments from third parties compared to those involving honesty yet violating fairness. In addition, regardless of the direction of violations, violations of honesty norms consistently resulted in third-party punishments, whereas violations of fairness norms only triggered penalties in the self-serving direction. These findings indicated that third parties exhibit lower tolerance for violation of the honesty norm than for fairness norm, highlighting a priority on honesty over fairness norm violation in punitive decisions.