Bonobos respond to distress in others: consolation across the age spectrum.

Zanna Clay,Frans B M De Waal,Ronald Noë

doi:10.1371/journal.pone.0055206

Abstract

How animals respond to conflict provides key insights into the evolution of socio-cognitive and emotional capacities. Evidence from apes has shown that, after social conflicts, bystanders approach victims of aggression to offer stress-alleviating contact behavior, a phenomenon known as consolation. This other-orientated behavior depends on sensitivity to the other's emotional state, whereby the consoler acts to ameliorate the other's situation. We examined post-conflict interactions in bonobos (Pan paniscus) to identify the determinants of consolation and reconciliation. Thirty-six semi-free bonobos of all ages were observed at the Lola ya Bonobo Sanctuary, DR Congo, using standardized Post-conflict/Matched Control methods. Across age and sex classes, bonobos consoled victims and reconciled after conflicts using a suite of affiliative and socio-sexual behaviors including embracing, touching, and mounting. Juveniles were more likely to console than adults, challenging the assumption that comfort-giving rests on advanced cognitive mechanisms that emerge only with age. Mother-reared individuals were more likely to console than orphans, highlighting the role of rearing in emotional development. Consistent with previous studies, bystanders were more likely to console relatives or closely bonded partners. Effects of kinship, affiliation and rearing were similarly indicated in patterns of reconciliation. Nearby bystanders were significantly more likely to contact victims than more distal ones, and consolation was more likely in non-food contexts than during feeding. The results did not provide convincing evidence that bystander contacts served for self-protection or as substitutes for reconciliation. Overall, results indicate that a suite of social, developmental and contextual factors underlie consolation and reconciliation in bonobos and that a sensitivity to the emotions of others and the ability to provide appropriate consolatory behaviors emerges early in development.

Highlights

Understanding how animals respond to social conflict provides key insights into the dynamics of animal social relationships and underlying socio-emotional and cognitive processes, such as perspective-taking, empathy, and emotion regulation [1]
Baseline (MC) levels of selfscratching found were higher in this population of bonobos compared to previous studies of chimpanzees using similar methodologies [2], and we found that rates of self-scratching during post-conflict periods without affiliation (PC) were not significantly higher compared to baseline (MC) (Mean 6 SD rate in Matched Control (MC) = 0.3760.22; Post Conflict (PC) = 0.4360.45; Wilcoxon signed-ranks test Z = 20.26, N1 = 32, N2 = 24, NS; Fig. 5, Table S4)
Unlike the PCs, we found no significant drop in scratching rate for contact vs. no contact MCs (Wilcoxon signed ranks: Z = 20.037, N = 20, P.0.05)

Summary

Introduction

Understanding how animals respond to social conflict provides key insights into the dynamics of animal social relationships and underlying socio-emotional and cognitive processes, such as perspective-taking, empathy, and emotion regulation [1]. Spontaneously receiving affiliative contact appears to reduce the victim’s distress following the conflict This phenomenon, known as consolation [9], is rare across the animal kingdom, so far having been demonstrated only in apes (Pan troglodytes) [2,9,10,11,12,13]; (P. paniscus) [14]; (Gorilla gorilla) [15,16], as well as a few other animals known for their advanced social cognitive skills, such as corvids [17,18], canids, [19,20] and elephants [21]. De Waal & Aureli [22] were the first to propose that consolation may set apes apart from monkeys, since monkeys do not seem to show such behavior [23]

Methods

Results

Conclusion