We welcome Glowacki's conceptual framework to describe and interpret the origins of human peace. We question the author's evaluation of the large discrepancies in the potential for peace between humans and other primates like chimpanzees and bonobos. Specifically, we argue that the competencies of other primates for peace, defined as the harmonious cooperation with outcasts and between different (sub)groups, are dismissed too easily. In response, we focus on three themes, namely, (1) the underestimation of nonhuman primate social capabilities, (2) the nonmonotonous effect of these capabilities on peacemaking, and (3) the anthropomorphization fallacy that might occur when the explanandum (here, the goal state of peace) is defined by human-centered values (e.g., equal responsibilities and rights across individuals and groups).

According to the author, peace between different groups is, among other capabilities, preserved by the capacity for social regulation, which is introduced as a key component of human cognition. This capacity, however, can also be observed in other primate species. Young chimpanzees, for example, learn to use new tools in directed interaction with older adults, while the latter receive physical attention in return (e.g., grooming). Likewise, chimpanzee males aspiring to lead their group benefit from strong social bonds. Accordingly, older adults often rise in the social hierarchy thanks to their sociability rather than dominance or physical strength (Newton-Fisher, Reference Newton-Fisher2004; Sandel et al., Reference Sandel, Langergraber and Mitani2020), a balance that is also critical for human leaders to prevent conflict or a revolt (Krueger et al., Reference Krueger, Grüning, Sundar, Forgas, Crane and Fiedler2022). Chimpanzees also show capacities of norm compliance and enforcement: In fact, it seems that they have a clear division of roles for conflict resolution (de Waal, Reference de Waal2022), for example, with the old females being able to settle aggressive disputes between young males. We want to make clear that the social components that are introduced as key human cognitions to facilitate peace – such as social learning and reciprocal behavior, as well as norm compliance and enforcement – are not lacking in other primates. At most, they are lesser in their extent.

Centrally, we want to make a plea for caution to conclude that humans are best equipped to establish and maintain peace, even if we assume their social capabilities to be comparatively high. In this regard, we present two arguments: First, we should not expect a monotonous effect of the presented key capacities to facilitate peace. For instance, an increased utility of intergroup cooperation leads to more intergroup interaction and more diverse kinds of interaction. Both can foster unique conflicts. That is, the complexity of human social interactions breeds error and misunderstandings. A more focused and reduced interaction with out-groups might, in some cases, be beneficial for a harmonious relationship between the groups. Similarly, the effects of norm enforcement on peace are ambiguous. If the enforcement reaches a certain extent, the attainment of peace should become less likely because individuals revolt in efforts to restore a measure of personal power and freedom.

Second, we urge caution to not commit the fallacy of defining the goal (i.e., peace) and conclusion (i.e., peace is most pronounced in the human species) by the starting point (i.e., human strengths and values). The result might be that the concept of peace is overfitted to human commonalities, rendering comparisons with other specifies confounded. As an illustration, peace as the “presence of generally harmonious relationships” (target article, sect. 1.1, para. 5) can refer to very different relational states. An egalitarian interaction and norm enforcement (i.e., equal responsibilities and rights among groups) might be what many would understand as a humane goal. However, a relationship between individuals as well as groups can be as harmonious without equality at its center but rather the opposite: A coalition between groups (e.g., tribes, kin groups, or clans) strictly led by one of the groups. Even between primate species this difference is apparent. While chimpanzees maintain harmony with a high asymmetry of power, bonobos do the opposite, preserving more of a democratic distribution of responsibilities and rights (de Waal, Reference de Waal2022). Both types of harmony are equally functional, leaving open the question of how to compare them with each other, let alone rank one above the other. We suggest that demonstrating interspecies discrepancies by applying human concepts of peace to other mammals may reflect interspecies differences in values rather than differences in capabilities to achieve peace, when peace as the harmonious intergroup relationship can be reached by several different means.

In conclusion, we appreciate Glowacki's attempt to provide an exhaustive perspective on the evolution of peace in humans. In our commentary, we seek to amend his framework by reevaluating other primates' social competencies and their potential for peace. We specifically point out that other primates like chimpanzees and bonobos show key components for peace the author presents, and we further argue that high degrees of these components are not exclusively beneficial for peace (between and within groups). Lastly, we advise caution in using human concepts of values and peace to conclude that peace can be especially facilitated by humans compared to other primates and mammals in general. This anthropomorphization commits the fallacy of defining the conclusion by its starting point.