Triadic social interactions operate across time: a field experiment with wild chimpanzees

Abstract

Social animals cooperate with bonding partners to outcompete others. Predicting a competitor's supporter is likely to be beneficial, regardless of whether the supporting relationship is stable or transient, or whether the support happens immediately or later. Although humans make such predictions frequently, it is unclear to what extent animals have the cognitive abilities to recognize others' transient bond partners and to predict others' coalitions that extend beyond the immediate present. We conducted playback experiments with wild chimpanzees to test this. About 2 h after fighting, subjects heard recordings of aggressive barks of a bystander, who was or was not a bond partner of the former opponent. Subjects looked longer and moved away more often from barks of the former opponents' bond partners than non-bond partners. In an additional experiment, subjects moved away more from barks than socially benign calls of the same bond partner. These effects were present despite differences in genetic relatedness and considerable time delays between the two events. Chimpanzees, it appears, integrate memories of social interactions from different sources to make inferences about current interactions. This ability is crucial for connecting triadic social interactions across time, a requirement for predicting aggressive support even after a time delay.

Coalitions in theory and reality: a review of pertinent variables and processes

“…All of these behaviours may add to the degree of coordination within the coalition. Recruitment is moreover very dependent on the identities of the target and the potential supporter, suggesting a good understanding of the relationship network, dubbed 'triadic awareness' (cf., de Waal, 1982), i.e., knowledge of the affiliative and dominance relationships between individuals other than oneself (Perry et al, 2004;Slocombe & Zuberbühler, 2007;Wittig et al, 2014). The fact that many primates have evolved specialized signals for the recruitment of allies strongly suggests the importance of coalitionary synergy, but this idea remains to be tested empirically.…”

Adaptations for social cognition in the primate brain

“…Thus, baboons use their memory of recent interactions to make inferences about the caller's intention to communicate with them. Experiments on free-ranging chimpanzees similarly suggest that individuals rely on memory of the nature and quality of recent interactions when deciding whether or not to respond to a group-mate's calls [54].…”

Social feedback and the emergence of rank in animal society

“…Recent evidence suggests that individuals in many species have the cognitive ability to use their observations of social interactions of others to inform their own behaviors, including several primate species [10,11,[42][43][44], ravens [45], hyenas [46], and fish [47][48][49][50]. However, while this evidence shows that individuals observe each other and react to these observations, we do not currently understand how individuals integrate information on the outcomes of their own interactions, with observations of others' interactions, in order to determine rank.…”