Zoon Politicon: The Evolutionary Roots of Human Sociopolitical Systems

Our primate ancestors evolved a complex sociopolitical order based on a social dominance hierarchy in multi-male/multi-female groups. The emergence of bipedalism and cooperative breeding in the hominin line, together with environmental developments which made a diet of meat from large animals fi tness enhancing, as well as cultural innovation in the form of fi re and cooking, created a niche for hominins in which there was a high return to coordinated, cooperative scavenging or hunting of large mammals. This, in turn, led to the use of stones and spears as lethal weapons. The availability of lethal weapons in early hominin society undermined the standard social dominance hierarchy of multi-male/multi-female primates. The successful sociopolitical structure that replaced the ancestral social dominance hierarchy was a political system in which success depended on the ability of leaders to persuade and motivate. This system persisted until cultural changes in the Holocene fostered the accumulation of material wealth, through which it became possible once again to sustain a social dominance hierarchy, because elites could now surround themselves with male relatives and paid protectors. This scenario suggests that humans are predisposed to seek dominance when this is not excessively costly, but also to form coalitions to depose pretenders to power. Much of human political history is the working out of these oppositional forces. Self-Interest and Cultural Hegemony Models of Political Power For half a century following the end of World War II, the behavioral sciences were dominated by two highly contrasting models of human political behavior. In biology, political science, and economics, a self-interest model held sway, wherein individuals are rational self-regarding maximizers. In sociology, social psychology, and anthropology, by contrast, a cultural hegemony model 26 H. Gintis and C. van Schaik was generally accepted. In this model, individuals are the passive internalizers of the culture in which they operate. The dominant culture, in turn, supplies the norms and values associated with role-performance, so individual behavior meets the requirements of the various roles individuals are called upon to play in daily life (Durkheim 1933/1902; Parsons 1967; Mead 1963). Contemporary research has been kind to neither model. There has always been an undercurrent of objection to the cultural hegemony model, which Dennis Wrong (1961) aptly called the “oversocialized conception of man.” Behavioral ecology alternatives were offered by Konrad Lorenz (1963), Robert Ardrey (1966/1997) and Desmond Morris (1999/1967), a line of thought that culminated in Edward O. Wilson’s Sociobiology: The New Synthesis (1975), the resurrection of human nature in Donald Brown’s Human Universals (1991), and Leda Cosmides and John Tooby’s withering attack in The Adapted Mind on the so-called “standard social science model” of cultural hegemony (Barkow et al. 1992). Meanwhile, the analytical foundations of an alternative model, that of gene–culture coevolution (see below), were laid by C. J. Lumsden and Edward O. Wilson (1981), Luca Cavalli-Sforza and Marcus Feldman (1973, 1981), and Robert Boyd and Peter Richerson (1985). In opposition to cultural hegemony theory, daily life provides countless examples of the fragility of dominant cultures. African-Americans in the era of the civil rights movement, for instance, rejected a powerful ideology that justifyied segregation, American women in the 1960s rejected a deep-rooted patriarchal culture, and gay Americans rejected traditional Judeo-Christian treatments of homosexuality. In succeeding years, each of these minority countercultures was largely accepted by the American public. In the Soviet Union, Communist leaders attempted to forge a dominant culture of socialist morality by subjecting two generations of citizens to rigid and intensive indoctrination. This failed to take hold and, following the fall of the USSR, was rejected whole cloth, without the need for extensive counter-indoctrination. Similar examples could be given from the political experience of many other countries, possibly all. Undermining the self-interest model began with the ultimatum game experiments of Güth et al. (1982), Roth et al. (1991), and many others. These experiments showed that human subjects may reject positive offers in an anonymous one-shot money-sharing situation if they fi nd the split to be unfair. The experiments of Fehr and Gächter (2000, 2002) showed that cooperation could be sustained in a fi nitely repeated public goods game if the punishing of free riders is permitted, despite the fact that the self-interest model predicts no cooperation. These and related fi ndings have led in recent years to a revision of the received wisdom in biology and economics toward the appreciation of the central importance of other-regarding preferences and character virtues in biological and economic theory (Gintis et al. 2005; Henrich et al. 2005; Okasha and Binmore 2012) Zoon Politicon: Roots of Human Sociopolitical Systems 27 The untenability of the self-interest model of human action is also clear from everyday experience. Political activity in modern societies provides unambiguous evidence. In large democratic elections, the rational self-regarding agent will not vote because the costs of voting are positive and signifi cant, but the probability that one vote will alter the outcome of the election is vanishingly small. Thus the personal gain from voting is vanishingly small. For similar reasons, if one chooses to vote, there is no plausible reason to vote on the basis of the impact of the outcome of the election on one’s self-regarding gains. It follows also that the voter, if rational, self-regarding, and incapable of personally infl uencing the opinions of more than a few others, will not bother to form opinions on political issues, because these opinions cannot affect the outcome of elections. Yet people do vote, and many do expend time and energy in forming political opinions. This behavior does not conform to the selfinterest model. It is a short step from the irrefutable logic of self-regarding political behavior that rational self-regarding individuals will not participate in the sort of collective actions that are responsible for growth in the world of representative and democratic governance, the respect for civil liberties, the rights of minorities and women in public life, and the like. In the self-interest model, only small groups of individuals aspiring to social dominance will act politically. Yet modern egalitarian political institutions are the result of such collective actions (Bowles and Gintis 1986; Giugni et al. 1998). This behavior cannot be explained by the self-interest model. Apart from professional politicians and socially infl uential individuals, electoral politics is a vast morality play in which models of the rational selfregarding actor are not only a poor fi t, but are conceptually bizarre. It took Mancur Olson’s The Logic of Collective Action (1965) to make this clear to many behavioral scientists, because virtually all students of social life had assumed, without refl ection, the faulty logic that rational self-regarding individuals will vote, and will “vote their interests” (Downs 1957). Defenders of the self-interest model may respond that voters believe their votes make a difference, however untenable this belief might be under logical scrutiny. Indeed, when asked why they vote, voters’ common response is that they are trying to help get one or another party elected to offi ce. When apprised of the illogical character of that response, the common reply is that there are in fact close elections, where the balance is tipped in one direction or another by only a few hundred votes. When confronted with the fact that one vote will not affect even such close elections, the common repost is that “Well, if everyone thought like that, we couldn’t run a democracy.” Politically active and informed citizens appear to operate on the principle that voting is both a duty and prerogative of citizenship, an altruistic act that is justifi ed by the categorical imperative: act in conformance with the morally correct behavior for individuals in one’s position, without regard to personal costs and benefi ts. Such mental reasoning, which has been called “shared 28 H. Gintis and C. van Schaik intentionality,” is implicated in many uniquely human cognitive characteristics, including cumulative culture and language (Sugden 2003; Bacharach 2006). Shared intentionality rests on a fundamentally prosocial disposition (Gilbert 1987; Bratman 1993; Tomasello and Carpenter 2007; Hrdy 2009). Human beings acting in the public sphere are, then, neither docile internalizers of dominant culture nor sociopathic personal gain maximizers. Rather, they are generally what Aristotle called zoon politikon—political beings (Aristotle 350 BC/2002). In this chapter we lay out a rather general framework for understanding this deep property of the human psyche, drawing in various ways on all the behavioral sciences. This framework will be used to elucidate the role of basic human political predispositions in creating and transforming sociopolitical structures. The Political and Economic Structure of Primate Societies Humans are one of more than two hundred extant species belonging to the Primate order. All primates have sociopolitical systems for regulating social life within their communities. Understanding human sociopolitical organization involves specifying how and why humans are similar to and different from other primate species. Similarities likely indicate that the trait was already present before humans evolved. For instance, many primate species, including humans, seek to dominate others and are adept at forming coalitions. It is thus likely that their common ancestor also possessed these traits. Dominance seeking and coalition formation in humans, then, are not purely cultural. Rather, humans are endowed with the genetic prerequisites for dominance striving and coalition formation. On the other hand, although chimpanzees engage in warlike raids where larger parties target and kill much smaller ones, no nonhuman primate species engages in human-style war, with large numbers of individuals on either side of a confl ict. Because hunter-gatherer societies do engage in such war, the presumption is that this predisposition is uniquely human and perhaps purely cultural, or derived from more basic genetic predispositions, which themselves may be the response to prior cultural changes, of which insider favoritism may be an example (Otterbein 2004; Bowles 2006, 2007; Bowles and Gintis 2011). Using this logic, we can examine the social structure of multi-male/multifemale monkey and ape societies (de Waal 1997b; Maestripieri 2007) to identify the elements of human sociopolitical organization that were likely present among the fi rst hominins. The focus here is on males because in human politics, historically, men were the main players. We ask about leadership, dominance, and alliances. Primates live in groups to reduce the risk of predation (Alexander 1974; van Schaik 1983), to facilitate the exchange of information as to food location (Eisenberg et al. 1972; Clutton-Brock 1974), and to defend food sources against competing groups (Wrangham 1980). However, these benefi ts largely Zoon Politicon: Roots of Human Sociopolitical Systems 29 arise through mutualism or as byproducts of grouping. Thus these groups rarely if ever engage in organized collective action. As a result, the primate form of group living has only limited need for leaders (i.e., individuals instrumental in initiating and coordinating group-level action). Instead, individuals vary in dominance based on pure physical prowess. In most primate species, both sexes form dominance hierarchies, in which more dominant individuals gain privileged access to food or mates, and tend to have higher fi tness as a result (Vigilant et al. 2001; Maestripieri 2007; Majolo et al. 2012). In many primate species, dominant females depend on alliances to maintain their position; for males the same is true in only a handful of primate species, including chimpanzees. Thus dominants rarely perform any grouplevel benefi cial acts. A rare exception includes males displaying toward predators, a behavior seen in a variety of primate species. Chimpanzees are an archetypical species when it comes to reconstructing the origins of the human political system. Dominant male chimpanzees provide little leadership, and they provide virtually no parenting. In many primate species, dominant males have suffi ciently high paternity certainty to induce them to provide protection to infants (Paul et al. 2000), but in chimpanzees, paternity concentration is so low (Boesch et al. 2006; Vigilant et al. 2001), most likely because chimpanzee females are scattered and cannot easily be located at all times, that males tend to ignore rearing the young. The only clear service they provide to the group is that they keep the peace by intervening in disputes (de Waal 1997b; Rudolf von Rohr et al. 2012). In short, the political structure of the chimpanzee society, like that of primates generally, is largely a system for funneling fi tness-enhancing resources to the apex of a social dominance hierarchy based on physical prowess and coalition-building talent. This holds basically for the bonobo as well, where monopolization of matings by particular males is even lower. Chimpanzee males rely on coalitions and alliances more than males in most other primate species. Their coalitions come in two major categories: rankchanging and leveling coalitions (Pandit and van Schaik 2003; van Schaik et al. 2006). At the top of the hierarchy, males often rely on a supporter to acquire and maintain top dominance (Goodall 1964; Nishida and Hosaka 1996; de Waal 1998). Because this implies that the top male does not necessarily have the highest individual fi ghting ability, he relies on the presence of an ally, and frequently depends on coalitions to protect his position (de Waal 1998; Boesch et al. 1998). In addition, multiple lower-ranking males may form coalitions to keep the top male(s) from taking too big a share of the resources. These coalitions do not change the dominance ranks of the participants, but intimidate the dominants into limiting damaging actions aimed at subordinates. Females similarly form such leveling coalitions to counter the arbitrary power of dominant males, especially in captivity (Goodall 1986). This pattern of political power based on the hierarchical dominance of the physically powerful along with a system of sophisticated political alliances to preserve or to limit the power 30 H. Gintis and C. van Schaik of the alpha male (Boehm and Flack 2010) is carried over, yet fundamentally transformed, in human society (Knauft 1991; Boehm 1999, 2011). This data on nonhuman primates, in general, and chimpanzees and other multi-male/multi-female species, in particular, is rather surprising and very important. It is surprising because, Aristotle notwithstanding, political theorists have widely assumed that political structure involves purely cultural evolution, whereas the primate data show roots to political behavior going back millions of years. The result is important because it lays the basis for an evolutionary analysis of human political systems. Such an analysis promises to elucidate the role of basic human political predispositions in reinforcing and undermining distinct sorts of human sociopolitical structures. The Evolutionary Trajectory of Primate Societies It would be useful if we could read past social structure from the historical record, but we cannot. The fossil record provides the most concrete answers to our evolutionary history, but is highly incomplete. There are, for instance, skeletal records of only about 500 individuals from our hominin past. Moreover, behavior does not fossilize and social structure, up until the past few thousand years, has not left direct marks in the earth. Thus we must investigate the relationship between genetic relatedness and phenotypic social organization from living primate species. The hominin lineage branched off from the primate main stem some 6.5 million years ago. The watershed event in the hominin line was the emergence of bipedalism. Bipedalism is well developed in Australopithecus afarensis, which appeared three million years after the origin of the hominin lineage. Homo ergaster (2.0–1.3 MYA) or H. erectus (1.9 MYA–143,000 years ago) was the fi rst currently documented obligate biped, having a relatively short arm:leg ratio. Bipedalism in hominins was critically dependent upon the prior adaptation of the primate upper torso to life in the trees. The Miocene Hominoid apes were not true quadrupeds; they had specialized shoulder and arm muscles for swinging and climbing, as well as a specialized hand structure for grasping branches and manipulating leaves, insects, and fruit. When the hominin line was freed from the exigencies of arborial life, the locomotor function of the upper limbs was reduced so that they could be reorganized for manipulative and projectile control purposes. Both a more effi cient form of bipedalism and the further transformation of the arm, hand, and upper torso became possible. Nonhominin primate species are capable of walking on hind legs, but only with diffi culty and for short periods of time. Chimpanzees, for instance, cannot straighten their legs, and require constant muscular exertion to support the body. Moreover, the center of gravity of the chimpanzee body must shift with each step, leading to a pronounced lumbering motion with signifi cant side-toside momentum shifts (O’Neil 2012). The hominin pelvis was shortened from Zoon Politicon: Roots of Human Sociopolitical Systems 31 top to bottom and rendered bowl-shaped to facilitate terrestrial locomotion without sideward movement, the hominin leg bones became sturdy, the leg muscles were strengthened to permit running, and the development of arches in the feet facilitated a low-impact transfer of weight from leg to leg. Thus, bipedality facilitates running effi ciently for great distances, although not approaching the speed of many large four-footed mammals. Today we celebrate obligate bipedality as the basis for human upperbody physical and psychomotor capacities for crafting tools and handicrafts. However, another major contribution of these capacities was for fashioning lethal weapons. Control of Fire: A Precondition of Social Sharing Norms The hominin control of fi re cannot be accurately dated. We have fi rm evidence from about 400,000 years ago in Europe (Roebroeks and Villa 2011) and about 800,000 years ago in Israel (Alperson-Afi l 2008), but it is likely that this key event happened in Africa much earlier. The control of fi re had strong effects on hominin cultural and phylogenetic evolution. First, the transition to obligate bipedality is much easier to understand if the hominins that made it had control of fi re (Wrangham and Carmody 2010). Prior to the control of fi re, humans almost certainly took to the trees at night, like most other primates, as a defense against predators. Because predators have an instinctive fear of fi re, the control of fi re permitted hominins to abandon climbing almost completely. Second, the practice of cooking food was a related cultural innovation with broad gene–culture coevolutionary implications. Cooking presupposes a central location to which the catch is transported, and hence requires abandoning the socially uncoordinated “tolerated theft” distribution of calories typical of food sharing in nonhuman primate species, in favor of a distribution based on widely agreed-upon fairness norms (Isaac 1978b). This major sociopsychological transition was probably made possible by the adoption of some form of cooperative breeding and hunting among hominins and had begun before the origin of H. erectus (van Schaik and Burkart 2010). In sum, the control of fi re and the practice of cooking were important preconditions for the emergence of a human moral order. Although the archeological record does not permit accurate dating for the regular use of fi re by hominins, (Sandgathe et al. 2011; Roebroeks and Villa 2011), it is clear that hominins with access to cooked food did not require the large colon characteristic of other primates. This allowed them to reduce the amount of time spent chewing food from the four to seven hours a day (characteristic of the great apes) to about one hour per day. With a smaller gut, less need for chewing, and more rapid digestion, hominins were liberated to develop their aerobic capacity and perfect their running ability (Wrangham and Carmody 2010). 32 H. Gintis and C. van Schaik From Gatherer to Scavenger Beginning around 2.5 MYA there was a major forking in the evolutionary path of our ancestors. The Australopithecines branched in at least two very different evolutionary directions: one led to the robust Australopithecines and a genetic dead end by about 1.4 MYA; the other, eventually, to the fi rst humans. It is likely that these diverging evolutionary paths were the response to novel environmental challenges. Coinciding with this hominin divergence was a shift in the global climate to frequently fl uctuating climatic conditions. Early hominins succeeded by learning to exploit the increased climate instability (Potts 1996; Richerson et al. 2001; O’Connell et al. 2002).1 The resulting adaptations enhanced hominin cognitive and sociostructural versatility. “Early bipedality, stone transport,...encephalization, and enhanced cognitive and social functioning,” Potts (1998:93) argues, “all may refl ect adaptations to environmental novelty and highly varying selective contexts.” This view is supported by the observation that greater encephalization occurred as well in many mammalian lineages (Jerison 1973). Eating the meat of large animals provided a niche for emerging hominins quite distinct from that of other primates and thus selected for the traits that most distinguish humans from apes. This much was clear to Darwin in The Descent of Man (1871). However, until recently, most paleoanthropologists assumed that meat was acquired through hunting from the australopithicine outset (Dart 1925; Lee and DeVore 1968). In fact, it now appears that early hominins, in the transition from the Pliocene to the Pleistocene, were more likely scavenger-gatherers than hunter-gatherers, of which there is fi rm evidence dating from 1.6 to 1.8 MYA. The fi rst proponents of early hominins as scavengers believed that the scavenging was “passive,” in that small groups of hominins took possession of carcasses only after other predators, upon being sated, abandoned their prey (Blumenschine et al. 1994). More recent evidence, however, suggests the prevalence of “competitive scavenging,” in which organized groups of humans supplied with primitive weapons, chased the killers and appropriated carcasses in relatively intact shape (Dominguez-Rodrigoa and Barba 2006). The implicit argument is that the hominin lethal weapons of the period were suffi cient to drive off other predators, and hence presumably to drive off live prey as well. To cripple or kill a large prey item, however, requires considerably more 1 deMenocal (2011) notes that Darwin (1859) long ago speculated on the role of climate change in human evolution, as did Dart (1925), and that modern fi ndings support the importance of climate-based selection pressures (Vrba 1995; Potts 1998), and specifi cally, climate variability. Examining the environmental records of several hominin localities, Potts (1998) found that habitat-specifi c hypotheses are disconfi rmed by the evidence; however, the variability selection hypothesis, which states that large disparities in environmental conditions were responsible for important episodes of adaptive evolution, was widely supported. Zoon Politicon: Roots of Human Sociopolitical Systems 33 powerful weapons. Thus, before poisoned, stone-tipped spears and arrows, the hunting of large prey was likely unrewarding (but see Liebenberg 2006). Flaked stone tool making, butchering large animals, and expanded cranial capacity all appear around 2.5 MYA, but there is no evidence that Australopithecenes hunted large game. Australopithecus and H. habilis were in fact quite small: adult males weighed under 100 pounds and females about 75 pounds. Their tools were primitive, consisting of stone scrapers and rough hammerstones. They therefore lacked the sophisticated weapons for hunting large and swift-moving prey. They are unlikely to have hunted effectively, but they could well have scavenged. Modern chimpanzees and baboons are known to scavenge the kills of cheetahs and leopards, so this behavior was likely in the repertoire of the earliest hominins. With highly cooperative and carefully coordinated maneuvers, they could have chased even ferocious predators. Hunting and scavenging small animals is not cost effective for large primates, while scavenging large animals requires group participation and effi ciently coordinated cooperation, both in organizing an attack on predators feeding on a large prey and in protecting against predators while processing and consuming the carcass (Isaac 1978a). Moreover, the only known weapons that might be used to scare off hunters and scavengers and potential predators were stones of the appropriate size and weight to be thrown at high velocity (Isaac 1987). Such stones had to be carefully amassed in strategic sites within a large scavenging area, so that when a scouting party located an appropriate food object, it could call others to haul the stones to the site of the dead animal, as a strategic operation preceding the appropriation of the animal carcass. These were the fi rst lethal projectile weapons. This scenario is supported by that fact that the fossils of large animals that have bone markings, indicating hominin fl aying and scraping with fl aked stone tools, are often found with stones that originated several kilometers away. Contemporary chimpanzees carry stones to nut-bearing trees and use them to crack the nuts, so this behavior was likely available to Australopithecenes. Chimpanzees, however, carry stones only several hundred meters at most, while H. habilis scavengers carried stones as far as ten kilometers. By contrast, neither the Oldowan tools of the period nor the later and more sophisticated Acheulean tools, found from the early Pleistocene up to about 200,000 years ago, show any sign of being useful as hunting weapons, although besides stones, scavengers of 500,000 years ago probably had sharpened and fi re-hardened spears to ward off competitive scavengers and threatening predators, at least after the domestication of fi re (Thieme 1997). By contrast, nonhuman primates use tools, but they do not use weapons to battle (McGrew 2004), although chimpanzees have been seen using spears fashioned from nearby tree branches to kill bushbabies that they discovered in tree hollows (Pruetz and Bertolani 2007). The emergence of lethal weapons, however primitive, was likely key to the evolution of hominid social organization. Bingham (1999) and Boyd et al. 34 H. Gintis and C. van Schaik (2010) stress the importance of the superior physical and psychomotor capacities of humans in clubbing and throwing projectiles as compared with other primates, citing Goodall (1964) and Plooij (1978) on the relative advantage of humans. Darlington (1975), Fifer (1987), and Isaac (1987) document the importance of these traits in human evolution. Bingham (1999) stresses that humans developed the ability to carry out collective punishment against norm violators, thus radically lowering the cost of punishing transgressors. Calvin (1983) argues that humans are unique in possessing the neural machinery for rapid manual-brachial movements that both allows for precision stone throwing and lays the basis for the development of language, which like accurate throwing depends on the brain’s capacity to orchestrate a series of rapidly changing muscle movements. These changes took place, in all likelihood, more than 700,000 years ago.2 Social Hierarchy: Dominance and Reverse Dominance Hunter-gatherer societies have been classifi ed into immediate-return and delayed-return systems. (Woodburn 1982). In the former, group members obtain direct return from their labor in hunting and gathering, with food lasting at most a few days. The tools and weapons they use are highly portable. In delayed-return societies, individuals hold rights over valuable assets, such as means of production (e.g., boats, nets, beehives), processed and stored food and materials, and herds of animals. In these societies we fi nd forms of social stratifi cation akin to those in modern societies: social dominance hierarchies in the form of lineages, clans, chiefdoms, and the like. The fossil record suggests, however, that the delayed-return human society is a quite recent innovation, appearing some 10,000 years ago, although on ecologically suitable locations, it may have existed earlier—most of these locations are now below sea level. H. sapiens thus evolved predominantly in the context of immediatereturn systems. The issue in “delayed return” is not the capacity for delayed gratifi cation or long-range planning, but rather the availability of accumulated wealth. Material wealth allows aspirants to positions of social dominance to control enough allies and resources to offset the capacity of subordinate individuals to disable and kill them. As long as the material gains from a position of social dominance exceed the cost of coalition building and paying guard labor, social dominance of the sort common in other primate societies can be reestablished 2 Fossil evidence indicates that hominins developed speech on the order of 1 MYA. The hyoid bone is a key element of speech production in humans. Martinez et al. (2008) show that hominin hyoid bones from 540,000 years ago are similar, and hence were inherited from their last common ancestor, Homo rhodesiensis, around 700,000 to 1,000,000 years ago. Using evidence from the acoustical properties of Middle Pleistocene fossil remains of the hominin inner ear, Martinez et al. (2004) argue that hominins of this period had auditory capacities similar to those of living humans. Zoon Politicon: Roots of Human Sociopolitical Systems 35 in human society.3 To avoid confusion, we will refer to societies that lack forms of material wealth accumulation as simple, rather than delayed-return, hunter-gatherer societies. Simple hunter-gatherer societies, Woodburn (1982:434) suggests, are “profoundly egalitarian...[they] systematically eliminate distinctions...of wealth, of power and of status.” Fried (1967), Service (1975), Knauft (1991), and others likewise comment on the egalitarian character of simple hunter-gatherer societies. What factors are responsible for such unusual egalitarianism? Here, we argue that it is due to the combination of interdependence and ability to punish