The Long‐Term Effects of Reconciliation in Japanese MacaquesMacaca fuscata

Abstract

With one exception, all previous studies of reconciliation in non‐human primates (friendly reunion between former opponents) have focused on demonstrating the immediate, short‐term effects despite the widely held view that reconciliation has a long‐term function of repairing social relationships following aggression. To investigate this long‐term function I compared mean interaction rates between opponents during the 10 d following reconciled and non‐reconciled conflicts to baseline levels of interaction. Aggression rates during the 10 d after non‐reconciled conflicts were significantly higher than the baseline rate, whereas after reconciled conflicts aggression was minimal. Similarly, grooming, proximity and approach rates during the 10 d after non‐reconciled conflicts were significantly lower than the baseline rate whereas grooming, proximity and approach rates in the 10 d after reconciled conflicts were restored to baseline levels. These results indicate that there are consequences to not reconciling with a former opponent and highlight the fact that these may be costly in terms of increased risk of long‐term aggression and reduced affiliation. The data support predictions from the Relationship‐Repair Hypothesis suggesting that reconciliation functions as a mechanism for the repair of social relationships damaged by aggression.