Bonobos Protect and Console Friends and Kin

Abstract

Post-conflict third-party affiliation has been reported to have different functional meanings, one of them being consolation. Here, we tested the main hypotheses that have been put forth to explain the presence of this phenomenon at a functional level in the bonobo: Self-Protection Hypothesis, Victim-Protection Hypothesis, Relationship-Repair or Substitute for Reconciliation Hypothesis, and Consolation Hypothesis. By analyzing the data collected over 10 years, we investigated what factors affected the distribution of both spontaneous third party affiliation (initiated by the bystander) and solicited third party affiliation (initiated by the victim). We considered factors related to the individual features (sex, rank, age) of victim and bystander, their relationship quality (kinship, affiliation), and the effect that third party affiliation had on the victim (such as protection against further attacks and anxiety reduction). Both spontaneous and solicited third party affiliation reduced the probability of further aggression by group members on the victim (Victim-Protection Hypothesis supported). Yet, only spontaneous affiliation reduced victim anxiety (measured via self-scratching), thus suggesting that the spontaneous gesture – more than the protection itself – works in calming the distressed subject. The victim may perceive the motivational autonomy of the bystander, who does not require an invitation to provide post-conflict affiliative contact. Moreover, spontaneous - but not solicited - third party affiliation was affected by the bond between consoler and victim, being the relationship between consoler and aggressor irrelevant to the phenomenon distribution (Consolation Hypothesis supported). Spontaneous affiliation followed the empathic gradient described for humans, being mostly offered to kin, then friends, then acquaintances. Overall, our findings do not only indicate the consolatory function of spontaneous third-party affiliation but they also suggest that consolation in the bonobo may be an empathy-based phenomenon.

The comparative study of empathy: sympathetic concern and empathic perspective‐taking in non‐human animals

“…Several studies have described the occurrence of unsolicited third‐party affiliations after conflicts in other ape species: bonobos ( Pan paniscus ) (Palagi, Paoli & Tarli, ; Clay & de Waal, ; Palagi & Norscia, ) and gorillas ( Gorilla gorilla and Gorilla beringei ) (Watts, 1995 a , b ; Cordoni et al ., ; Mallavarapu et al ., ). In bonobos, close relationships positively affected only unsolicited affiliation rates along an empathic gradient, being mostly offered to kin, then friends and, finally to acquaintances (Palagi et al ., ; Clay & de Waal, ; Palagi & Norscia, ). Unsolicited bystander affiliation effectively reduced the distressed party's anxiety in bonobos (measured through self‐scratching behaviour, an indicator of anxiety) (Palagi & Norscia, ).…”

“…In bonobos, close relationships positively affected only unsolicited affiliation rates along an empathic gradient, being mostly offered to kin, then friends and, finally to acquaintances (Palagi et al ., ; Clay & de Waal, ; Palagi & Norscia, ). Unsolicited bystander affiliation effectively reduced the distressed party's anxiety in bonobos (measured through self‐scratching behaviour, an indicator of anxiety) (Palagi & Norscia, ). Data on unsolicited bystander affiliation in gorillas are not conclusive due to fewer studies and inconsistent results between wild mountain gorillas (Watts, 1995 a , b ) and captive groups of western gorillas (Cordoni et al ., ; Mallavarapu et al ., ).…”

“…Thus, unsolicited third‐party affiliation in chimpanzees (Fraser et al ., ), bonobos (Clay & de Waal, ; Palagi & Norscia, ) and Tonkean macaques (Palagi et al ., ) reduced behavioural indicators of stress in the victims, satisfying a crucial feature of consolation: distress alleviation. It also met the familiarity bias criterion, being offered mostly to familiar conspecifics.…”

Bonobos (Pan paniscus) vocally protest against violations of social expectations.

“…aggression in bonobos are generally low (Clay & de Waal, 2013) and in some cases, 265! virtually absent (Palagi & Norscia, 2013). Expected aggression included all cases in 266!…”

Functions of post‐conflict affiliation with a bystander differ between aggressors and victims in Japanese macaques

“…Consolation, affiliation between a bystander and a victim (de Waal & van Roosmalen, ), helps reduce post‐conflict stress of victim (Fraser, Stahl, & Aureli, ; Palagi & Norscia, ). Consolation initiated by a victims is called solicited consolation, as distinguished from spontaneous consolation that is initiated by a bystander (McFarland & Majolo, ).…”