Costly apologies communicate conciliatory intention: an fMRI study on forgiveness in response to costly apologies

Reconciliation is an integral part of our social lives. Nevertheless, if a victim perceives the risk of further exploitation by his/her transgressor as non-negligible, the victim may well have difficulty forgiving the transgressor. Therefore, a key ingredient of reconciliation is the transgressor's sincere apology. Theoretical and empirical studies have shown that transgressors can make their apologies credible by incurring a substantial cost. Therefore, we hypothesized that costly apologies, compared to non-costly apologies (i.e., simply saying "sorry"), would effectively communicate a transgressor's conciliatory intention. In a functional magnetic resonance imaging (fMRI) study, participants were asked to imagine a friend committing a mild interpersonal transgression (e.g., standing up the participant) and then apologizing in a costly fashion, apologizing in a non-costly fashion, or not apologizing at all. Compared to non-costly apologies and non-apologies, costly apologies (signals of conciliatory intention) more strongly activated the theory-of-mind network (i.e., bilateral temporoparietal junction, precuneus, medial prefrontal cortex). Moreover, we did not observe any significant differences in brain responses to non-costly apologies and non-apology controls. These results underscore the importance of costly signals in human communication and in human peace-making in particular.