It is also worth noting that offensive realism may often be derided because we do not want it to be true. He argues, like Waltz, that the anarchic international system is responsible for much troublesuspicion, fear, security competition, and great power warsin international politics. Volume 1: Chimpanzees, Bonobos, and Gorillas, Natural Selection and Social Theory: Selected Papers of Robert Trivers, The Logic of Collective Action: Public Goods and the Theory of Groups, Governing the Commons: The Evolution of Institutions for Collective Action, Punish or perish? However, offensive realism is one of the most compelling current theories for explaining major phenomena across the history of international politics, such as great power rivalries and the origins of war. Hunter gatherers have recurrent tendencies, including hostility toward members of different societies, and for killing to be carried out in relative safetythat is, only when there is a strong asymmetry in power between subgroups, such as in a raid or ambush (the imbalance of power hypothesis). His most recent book, with Brian Mazanec, is Deterring Cyber Warfare: Bolstering StrategicStability in Cyberspace (Palgrave, 2014). Individuals fight when benefits are expected to exceed costs (on average), and not otherwise. Will the outsider be a threat to oneself or to ones family? The international system is anarchic. This collective benefit points to the special and much more significant role of anarchy at a higher levelanarchy between groups. Our theory is also unlimited in domain, explaining behavior wherever there are human actors and weak external constraints on their actions, from ancestral human groups, ethnic conflict, and civil wars to domestic politics, free markets, and international relations. Evolutionary theory makes three major contributions to the offensive realist theory of international politics: (1) a novel ultimate cause of the primary traits of offensive realist behavior (self-help, power maximization, and fear); (2) an extension of offensive realism to any domain in which human actors compete for power (e.g., civil war, ethnic conflict, or domestic politics); and (3) an explanation for why individual leaders themselves, not just states, behave as they do. Up to now, our claims have focused on traits that are common to all humans. The Ngogo group annexed their newly captured area, increasing their territory by more than 20 percent.Reference Mitani, Watts and Amsler1. These traits help to explain why humans (including political leaders) will behave, in the proper circumstances, as offensive realists expect them to behave.  The five bed-rock assumptions of Mearsheimer's theory of offensive realism are: When grounded in evolutionary theory, offensive realism need not simplify structure to interpret behavior and can parsimoniously develop and test corollaries over the entire span of human history. What is more important is the ecological differences and similarities that we shared with the two species. In short, you do not need group selection to explain altruism. Waltzs core concept in Theory of International Politics is the anarchy that reigns in world politics. Of the many features of hunter-gatherer society and organization, we focus on intergroup relations, since these are most relevant to the behaviors associated with international relations. Given group selections theoretical constraints, it should be a last-resort explanation (subject to empirical testing), not a first point of call. As we show in the next section, competition between groups is especially significant for human evolution, and for international politics, precisely because it is at the intergroup level where anarchy reigns supreme and is much harder to suppress. In this article, we ask whether human nature may predispose us, like our nonhuman primate cousins, to behave as offensive realists. Others are even older, such as the limbic system, hormones, and sexual dimorphism, which are shared by countless species extending across all mammals and beyond. Debates about evolved human propensities have often centered on whether human behavior more closely resembles the behavior of common chimpanzees or that of bonobos (pygmy chimpanzees that live in central Africa and are somewhat less aggressive than common chimpanzees). Anarchy is, ironically, the ordering principle of the global state system and the starting point for most major theories of international politics, such as neoliberalism and neorealism.42,Reference Keohane43,Reference Jervis44,Reference Nye45 Other theoretical approaches, such as constructivism, also acknowledge the impact of anarchy, even if only to consider why anarchy occurs and how it can be circumvented.Reference Wendt46,Reference Onuf47 Indeed, the anarchy concept is so profound that it defines and divides the discipline of political science into international politics (politics under conditions of anarchy) and domestic politics (politics under conditions of hierarchy, or government). Our evolutionary approach predicts the same behavior as offensive realism but derives from a different ultimate cause. Offensive realism based on evolutionary theory makes the same predictions for state behavior, but the ultimate causal mechanism is different: human evolution in the anarchic, dangerous, and competitive conditions of the late-Pliocene and Pleistocene eras. In either case, it is females rather than males that are the limiting factor in sexual competition, making male competition for available females intense. Theorists have had to explain how cooperation could occur in the face of significant individual self-interest, the difficulties of collective-action, and the free-rider problem.Reference Boyd175,Reference Olson176,Reference Ostrom177 Special conditions are needed for cooperation to emerge and remain stable among unrelated individuals.178,Reference Sigmund179 Typically, those special conditions are ones that make helping advantageous to the genes responsible for the behavior. Something inherent in our biological makeup motivates us to try to improve, or at least maintain, our standing against those with whom we compete for important positional resources.Reference Frank94 In the context of evolutionary theory, dominance usually means that particular individuals in a social group have priority of access to resources in competitive situations.Reference Milinski, Parker, Krebs and Davies95 A wide variety of animals exhibit a form of social organization called a dominance hierarchy, in which members of a social group each have a status rank descending from the alpha male down through all the other individuals to the lowliest subordinates. By contrast, as rational actor theorists would expect, hunter-gatherers are averse to the risk of fighting symmetric battles with roughly equivalent numbers on each side.82 Importantly, sustained instances of imbalances of power over evolutionary history would have led to the selection of contingent aggression. He received a masters degree (1974) in international relations from the University of Southern California, as well as a masters degree (1978) and a Ph.D. (1981) in government from Cornell University. Classical realists (such as Thucydides, E.H. Carr, Arnold Wolfers, and Hans Morgenthau) and offensive realists share the assumption that states seek to maximize power - that states are relentless seekers of power and influence.Specifically, for classical realists "nations expand their political interests abroad when their relative power increases . 2018. He also frequently participated in public debates by contributing op-ed articles to the The New York Times and other national newspapers. Men, more often than women, lead states. If anchored on evolutionary theory, offensive realism allows new insights to elucidate why individuals and substate groups are self-interested, vie for power, and fear each other, and it can explain political behavior and war that occurred long before the creation of the modern state system in 1648. We recognize that a challenge to the theory of offensive realism is the empirical mix of cooperation and conflict in the real world. The optimistic message of our argument is that understanding human nature will make efforts toward international institutions, democracy, and cooperation more effective. On the contrary, it provides or adds to the reasons why we demand and need them, and indeed why they are so hard to establish and maintain. Psychologists argue that the ingroup/outgroup distinction develops from a need for social identity. Similarly formidable obstacles to cooperation exist in international relations. Given the prominence of the concept in present-day international relations theory, it is striking that anarchy only took hold as a central feature of scholarship in recent decades, since the publication of Kenneth Waltzs Theory of International Politics in 1979. All three species descended from an (unknown) common ancestor. Whereas classical realists such as Hans Morgenthau had traced international conflicts to the natural propensity of political leaders to seek to increase their power, neorealists (or structural realists) such as Waltz located the cause of war in the structure of international relations. In the Pleistocene era, this strategy could have been an option with some resources but not others. Therefore, to the extent that it matters, let us address the bonobo-chimpanzee issue briefly here, because certain phylogenetic and socio-ecological factors suggest that we are more like chimpanzees than bonobos. Our ancestors not only lived in a state of anarchy for millions of years, but they also evolved in that state of anarchy and consequently developed cognitive and behavioral adaptations specifically to survive and reproduce effectively under conditions of anarchy. In short, on the basis of the family tree, there is little reason to assume that humans should be more or less like bonobos or chimpanzees. Mearsheimer argues that anarchy is the fundamental cause of such behavior. This has been done extensively many times elsewhere.Reference Barkow7,Reference Hodgson and Knudsen8,Reference Barkow, Cosmides and Tooby9,Reference Thayer10,Reference Sidanius, Kurzban, Sears, Huddy and Jervis11,Reference Alford and Hibbing12,Reference Gat13,Reference Rosen14,Reference Pinker15 Furthermore, we do not intend to make the full case for whether states do or do not act as predicted by offensive realism, which has also been done extensively elsewhere.Reference Layne16,Reference Mearsheimer17,Reference Labs18 The article focuses instead on our novel theoretical question: Do the core behavioral assumptions underlying the theory of offensive realism map onto evolved human nature? Third, by acknowledging that the social and natural sciences are both necessary to understand human behavior, we advance consilience. Core Assumptions of Realism (5) 1. Some evidence suggests that the separation between common chimpanzees and bonobos was quite recent, occurring perhaps only 0.86 million to 0.89 million years ago, although it remains possible that the separation occurred much earlier, between 1.5 million to 2.5 million years ago.Reference Won and Hey166 Either way, humans separated from our common ancestor with both chimpanzee species long before, about 5 million to 6 million years ago. First, ambitious leaders self-select themselves into seeking high-profile roles in the first place.Reference Ehrenhalt191 Second, strong leaders are selected into power over weak-willed or hesitant candidates.Reference Todorov, Mandisodza, Goren and Hall192,Reference Van Vugt and Ahuja193 Third, leaders rise to the top of their respective hierarchies through an intensively competitive process that compels them to be increasingly attentive to self-interest and self-preservation.Reference Shenkman194 Fourth, once in power, decision-makers tend to heed hawkish rather than dovish advice.Reference Kahneman and Renshon195 Fifth, the experience of power itself is well known to corrupt, precisely because being a leader elevates ones sense of worth and power.196 Taking these phenomena together, a skeptic of our argument that humans are generally egoistic, dominance-seeking and groupish may nevertheless concede that the small subset of humans that become political leaders tend to express these traits.