These articles are also published in Behaviour, Volume 151, Nos. 2/3 (February 2014).
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The evolution of behavior is sometimes considered irrelevant to the issue of human morality, since it lacks the normative character of morality (‘ought’), and consist entirely of descriptions of how things are or came about (‘is’). Evolved behavior, including that of other animals, is not entirely devoid of normativity, however. Defining normativity as adherence to an ideal or standard, there is ample evidence that animals treat their social relationships in this manner. In other words, they pursue social values. Here I review evidence that nonhuman primates actively try to preserve harmony within their social network by, e.g., reconciling after conflict, protesting against unequal divisions, and breaking up fights amongst others. In doing so, they correct deviations from an ideal state. They further show emotional self-control and anticipatory conflict resolution in order to prevent such deviations. Recognition of the goal-orientation and normative character of animal social behavior permits us to partially bridge the is/ought divide erected in relation to human moral behavior.
Sexual contacts are thought to play an important role in regulating social tension in bonobos (Pan paniscus), and are especially common following aggressive conflicts, either between former opponents or involving bystanders. Nevertheless, research on the factors determining post-conflict sexual contacts, their effectiveness in reducing social tension and the nature of post-conflict sexual behaviour is scarce. Here, we collected data on post-conflict affiliative contacts in bonobos occurring between former opponents (reconciliation) and offered by bystanders towards victims (consolation) to investigate the role of sexual contacts in the regulation of aggressive conflicts compared to non-sexual affiliation behaviours. We tested whether post-conflict sexual contacts: (1) alleviate stress, (2) confer reproductive benefits, (3) mediate food-related conflict and (4) repair valuable social bonds. 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. Consolation and reconciliation were both marked by significant increases in the occurrence of sexual behaviours. Reconciliation was almost exclusively characterized by sexual contacts, although consolation was also characterized by increases in non-sexual behaviours, such as embrace. Adults were more likely to engage in post-conflict sexual contacts than younger bonobos. Consistent with the stress-alleviation hypothesis, victims receiving sexual consolatory contact showed significantly lower rates of self-scratching, a marker of stress in primates, compared to receiving non-sexual contact. Post-conflict sexual contacts were not targeted towards valuable social partners and they did not confer obvious reproductive benefits; nor were they used to mediate food-related conflicts. Overall, results highlight the role of sex in regulating tension and social conflicts in bonobos.