This is a robust contribution to the literature on the evolution of warfare and peacemaking. We found many of the arguments to be compelling and agree with much that Glowacki presents. Here we extend and contextualize the argument Glowacki offers regarding evolutionary dynamics, commenting on the extent and complexity of cultural dynamics in the genus Homo as it relates to the emergence of peacemaking. We suggest a broader engagement with the range of Pleistocene data offers a deeper time frame and a bit more nuance.

Glowacki argues that peace is the product of cultural technologies that depend on factors that have recently emerged in our species' history, including social institutions and cultural mechanisms for preventing and resolving conflicts. We agree with the core argument and have published on it and related themes (Fuentes, Reference Fuentes2017a; Kim & Kissel, Reference Kim and Kissel2018; Kissel & Kim, Reference Kissel and Kim2019). However, Glowacki implies that this suite of capacities to invent peace developed primarily within the last 100,000 years or so, drawing on, but different from, preexisting patterns of cooperation and conflict. This falls dangerously close to the refuted “behavioral modernity” versus “anatomical modernity” position (Kissel & Fuentes, Reference Kissel and Fuentes2021). We argue that the behavioral abilities that permitted the potential presence of warfare existed before 100,000 years ago and would also have allowed for the development of “peacemaking” (or “peacefare”; Kim & Kissel, Reference Kim and Kissel2018) as well. If members of the genus Homo could organize and cooperate in highly sophisticated ways, for example, hunting, material exchanges, cultural diffusion across large distances, complex care of injured and deceased, and other communal/joint activities (Brooks et al., Reference Brooks, Yellen, Potts, Behrensmeyer, Deino, Leslie and Clark2018; Dapschauskas, Göden, Sommer, & Kandel, Reference Dapschauskas, Göden, Sommer and Kandel2022; Hrdy & Burkart, Reference Hrdy and Burkart2020; MacDonald, Scherjona, van Veena, Vaesena, & Roebroeks, Reference MacDonald, Scherjona, van Veena, Vaesena and Roebroeks2021; Spikins, Dytham, French, & Seren, Reference Spikins, Dytham, French and Seren2021), and could use sophisticated communication and intergroup coordination in those endeavors, then populations of Homo could have started to develop and deploy capacities for peacefare well before 100,000 years ago. Glowacki acknowledges that underlying elements in these general patterns existed by ~300,000 years ago, but argues the key forms of social structure and cultural institutions of this earlier period did not resemble, sufficiently, the kinds he describes for later eras. Our view is that members of the genus Homo possessed the sufficient cognitive/physical/social toolkits, whether yesterday, 100,000 years ago, or 300,000 years, to develop the forms of cultural institutions necessary for peacefare (Fuentes, Reference Fuentes2017b; Kim & Kissel, Reference Kim and Kissel2018).

In relation to the complexities in intergroup dynamics that solidify in the last few hundred millennia of the Pleistocene, Glowacki writes that intergroup exchange in particular allowed humans to build the cultural technologies beneficial in meeting the challenges of the ecological and social environments. Citing Polly Wiessner, Glowacki writes that more recent periods of peace may have fueled increased social complexity due to an expansion of exchange between groups that would otherwise be in conflict. Clearly this is possible. We would add here that periods of conflict, with constructions of identity/solidarity against outside groups, cooperation for defense as well as policing, and sacrificial ceremonies, may have also fueled substantive changes in social and technological complexity. These dynamics may also predate 100,000 years ago. One of us has argued previously how violent competition between factions/groups, both intra- or intersocietal, is a key factor for development of sociopolitical complexity and innovations in cultural institutions (Kim, Reference Kim, Bondarenko, Kowalewski and Small2020).

Glowacki suggests that for contemporary small-scale societies, participation is risky and conflict is motivated by a range of private incentives. We think much more can be said about motivations for populations of the genus Homo participating in coalitionary cooperation and conflict, particularly if they are to result in “positive-sum outcomes,” which themselves would be highly complex and culturally contingent. Equally significant would have been cultural attitudes and perceptions about why violence is needed or ought to be actively avoided or restricted. This is, as partially noted by Glowacki, something that distinguishes human warfare and peacefare, even at small scales, from other kinds of coalitionary violence in other species (Kim & Kissel, Reference Kim and Kissel2018). Sometimes people participate because of a perceived attack or threat, and these perceptions could be related to beliefs that need not be physically manifest (Fuentes, Reference Fuentes2019; Whitehead, Reference Whitehead and Whitehead2004).

It is possible that Glowacki's focus on the core elements of game theory, economic models, and rational choice behaviors/incentives tends to elide much in actual motivations and belief systems, emphasizing instead the “rational” actor assessment. For humans, warfare and peacefare can be motivated by a perceived, and believed, collective good for the home community, even one that is not quantifiable. Arguably, participation in active warfare and peacefare can stem from a myriad of complex reasons and shared beliefs, much of which are simultaneously basis for, and derived from, cultural institutions and perceptions.

Glowacki's approach of creating positive-sum outcomes may not fully capture the variable nature of experiences in gains and losses for groups across the middle and terminal Pleistocene. Humans participate in warfare and peacefare for different reasons and in different contexts, many of which are not assessable primarily in an economic model, and these experiences may not be capable of being “summed.” We might perceive positive–positive outcomes on the aggregate, but peace as a lived dynamic is highly variable and subjective, and is not an absolute condition (it may be marked by perceived conditions of peace for some but losses/injustices, unfair treatment for others). A generally positive-sum outcome may run the risk of overlooking negative conditions for some within a society. Peace for some might come at a cost for others. For instance, some might claim that American society today is generally at peace, but many community members might feel very differently (and rightfully so) given various kinds of conflict, injustice, and an absence of peace as related to outcomes from forms of cultural or structural violence (Kim, Reference Kim2012).

In sum, we applaud Glowacki's exploration of the conditions required for peace and war and welcome more discussions on how these are not opposites but epiphenomenal of deeper issues of how humans construct their worlds and communities.