Climate change, nuclear and biochemical weapons exposure, pandemics, and “disruptive technologies” threaten life on earth. According to the bulletin of the atomic scientists who developed a “doomsday clock” to predict man-made global catastrophe, we are in a “time of unprecedented danger” (Mecklin, Reference Mecklin2023). As we collectively step onto a precipice in which humanity might cease to exist, the “fog of war” continues to stymie human creativity and ingenuity (Morris, Reference Morris2003) — the only tools we have capable of mitigating this crisis. Glowacki's “The evolution of peace,” an anthropological analysis of the coevolution of peace and war, is teaming with new insights and approaches to international conflict that are seamlessly accessible to all, and simultaneously capable of ending war. These insights offer a road map for achieving a safe haven for international and interdisciplinary friendship and scholarship.

Glowacki's main thesis is that need-based sharing with interdependent out-groups provides the motivation for peace, which is a similar argument we have made in earlier work (Brown, Brown, Knickrehm, & Teske, Reference Brown, Brown, Knickrehm and Teske2005). However, Glowacki's intriguing contribution is that war begins with conflict within the group, as opposed to outside of it. He suggests that the decision to go to war is almost always made unilaterally by a single individual (or relatively small collection of individuals) who elevate their own needs (e.g., for revenge, status, freedom) above the needs of the in-group or nation. According to Glowacki, war might be in the best interest of an individual, but peace is always in the best interest of the group.

Glowacki finds remedy in polydomous ants that share resources (peacefully) with other ants from spatially distinct nests. He writes that ants “achieve peace through an entirely different pathway unavailable to most animals” (target article, sect. 8, para. 7). These ants “achieve positive-sum interdependent relationships” with one another that align the interests of the in-group. As Glowacki puts it, “One ant cannot asymmetrically benefit through intergroup aggression compared to their other group members. If aggression or cooperation is the best strategy for an ant society, the payoffs apply symmetrically to all workers in that society” (target article, sect. 8, para. 7). Glowacki writes, “understanding how ants achieve [these] relationships will potentially provide new insights into the conditions that prevent and promote intergroup cooperation” (target article, sect. 8, para. 7).

In our own theoretical work, we have sought to understand these positive-sum interdependent dynamics, relying on Kropotkin's (Reference Kropotkin1910) argument that the animal kingdom is better characterized by individuals helping one another than by individuals competing with one another (Brown, Reference Brown1998, Reference Brown1999; Brown & Brown, Reference Brown and Brown2006). Positive-fitness interdependence occurs in social mammals, birds, and other species who share evolutionary fates. Although this often involves shared genes, fitness interdependence can also occur when individuals have a common experience or goal or fate, as when individuals play together, raise children together, or respond similarly to a perceived threat or life-enhancing opportunity. From an evolutionary perspective, these are all potential cues for shared reproductive outcomes.

Humanity is powerfully equipped to recognize states of fitness interdependence and respond to another's need with other-focused motivation, using what Bowlby (Reference Bowlby1969) has referred to as the “caregiving behavioral system” (Brown & Brown, Reference Brown and Brown2015; Brown, Brown, & Preston, Reference Brown, Brown, Preston, Brown, Brown and Penner2012). When the “caregiving system” guides behavior, we can expect a greater inclination toward developing interdependent alliances with out-group members. Importantly, there is supporting (and provocative) evidence that perceived interdependence is associated with interpersonal cooperation in everyday life (Columbus, Molho, Righetti, & Balliet, Reference Columbus, Molho, Righetti and Balliet2021) and in negotiation experiments (e.g., Cao, Kong, & Galinsky, Reference Cao, Kong and Galinsky2020; Woolley & Fishbach, Reference Woolley and Fishbach2019), and with reductions in ethnic conflict in the real world (Varshney, Reference Varshney2002).

In discussing prerequisites for peace, Glowacki argues that “the key challenge” for society is that of replacing in-group social norms that reward aggression (e.g., Sherif, Reference Sherif1954) with ones that “prohibit aggression and implement coercive sanctions for those who violate them” (target article, sect. 3.3.2, para. 1). But how is norm replacement accomplished? Presumably, social norms are not arbitrary motivators of behavior; they emerge from behavioral interactions of group members (Morsky & Akcay, Reference Morsky and Akcay2019), and, at least in some instances, reflect evolved solutions to specific adaptive problems, such as resource unpredictability (Kameda, Takezawa, & Hastie, Reference Kameda, Takezawa and Hastie2003). In our view, a more direct and less coercive approach would start with identifying patterns of perceived fitness interdependence, positive and negative, and create or repurpose activities that bring people together in cooperative ventures. A key to preventing war might be to understand that two parties (in- or out-group members) who are driven to compete fiercely or work in opposition to one another (negative interdependence) may, nevertheless, find it mutually beneficial to cooperate in an effort to help others (positive interdependence). Sherif identifies this basic strategy; however, he leverages the concept of a common enemy to create positive interdependencies among warring neighbors. By conceiving of positive interdependence more broadly, it may be possible to help everyone recognize their shared fate. As Kim Jong-un, supreme leader of North Korea, said, “I am a father … I don't want my kids to carry nuclear weapons on their backs the rest of their lives … so let's come up with solutions” (attributed by Woodward, Reference Woodward2020, p. 100).

The challenge for peacemakers would be to get each party to reframe negatively interdependent situations, and/or reinforce and extend the scope of those characterized by positive interdependence. To transition to interdependent social environments, groups would have to support the creation and maintenance (as opposed to disruption or dissolution) of close interpersonal relationships in the context of perceived safety, a prerequisite for activating the caregiving system. Unfortunately, cultural values that de-emphasize the importance of early childhood experiences (Ainsworth, Blehar, Waters, & Wall, Reference Ainsworth, Blehar, Waters and Wall1978; Belsky, Steinberg, & Draper, Reference Belsky, Steinberg and Draper1991; Brown & Brown, Reference Brown and Brown2015; Chisholm, Ellison, Evans, Lee, & Lieberman, Reference Chisholm, Ellison, Evans, Lee and Lieberman1993; MacDonald, Reference MacDonald1997) and news media that thrives on threat do little to help in this endeavor. Nevertheless, the creative arts and the media are also promising tools for cultivating awareness of positive interdependencies with one another (Kullberg & Singer, Reference Kullberg, Singer, Brown, Brown and Penner2012). As described by Jing et al. (Reference Jing, Gries, Li, Stivers, Mifune, Kuhlman and Bai2017, p. 2), “War or peace … critically depends upon how the citizens and leaders of great powers perceive their interdependence” [emphasis added].