Consolation in bonobos: a possible empathetic tactic in conflict management

Consolation is an interaction in which an involved bystander initiates friendly contact with a victim of aggression. While in humans this phenomenon appears to be a stress reliever, in other apes its function is puzzling. We investigated the role of consolation in bonobos, by considering the contextual framework and victim's distress. This last aspect was evaluated by measuring scratching, a displacement activity associated to anxiety. We analyzed 555 post-conflict and match-control focal observations (PC-MC) gathered on a bonobo group hosted at the Apenheul Primate Park (The Netherlands) in the non continuous period spanning June 2000-October 2009. We tested the effect of conflict characteristics (outcome and intensity), presence of reconciliation, and individual features (sex, rank, and age class) on the occurrence of consolation. Additionally, we checked for the effect of consolation victim's scratching levels by comparing them after and in absence of consolation. Among all variables, we found that only reconciliation significantly explained the occurrence of consolation. Specifically, consolation appears to be a substitute of reconciliation. Moreover, victim's scratching level was significantly reduced after receiving consolation by a group mate than in absence of third-party contact. Overall in bonobos, as well as in Homo sapiens, consolation plays a role in reducing stress in the victims of aggressions, thus informing its empathic role.