Monogamy, strongly bonded groups, and the evolution of human social structure

Abstract

Human social evolution has most often been treated in a piecemeal fashion, with studies focusing on the evolution of specific components of human society such as pair-bonding, cooperative hunting, male provisioning, grandmothering, cooperative breeding, food sharing, male competition, male violence, sexual coercion, territoriality, and between-group conflicts. Evolutionary models about any one of those components are usually concerned with two categories of questions, one relating to the origins of the component and the other to its impact on the evolution of human cognition and social life. Remarkably few studies have been concerned with the evolution of the entity that integrates all components, the human social system itself. That social system has as its core feature human social structure, which I define here as the common denominator of all human societies in terms of group composition, mating system, residence patterns, and kinship structures. The paucity of information on the evolution of human social structure poses substantial problems because that information is useful, if not essential, to assess both the origins and impact of any particular aspect of human society.

Men’s status and reproductive success in 33 nonindustrial societies: Effects of subsistence, marriage system, and reproductive strategy

“…2). This reduction in reproductive payoffs to high status could reflect increased interdependence in food production, greater ability to form leveling coalitions, increased payoffs to mateguarding due to changes in sex ratio, or increased opportunities for female choice (75,78). Arranged marriage has likely been common since at least the early migrations of humans out of Africa (79), but even when male kin control marriage arrangements, females may exert significant mate choice via surreptitious extrapair copulation (80).…”

Lethal coalitionary aggression and long-term alliance formation among Yanomamö men

“…One possibility is that humans and chimpanzees inherited a common ancestry and psychology for coalitionary violence that initially was restricted to genetically related males from the same natal community; however, after pair bonding and the metagroup level of social organization evolved in humans, that psychology was coopted to motivate alliances with genetic and social kin residing in other communities. If this notion is correct, a potential scenario for the evolution of human social structure involves an initial phase in which pair-bonding, bilateral kinship, and descentgroup exogamy set favorable conditions for the recognition of cross-cousins and affines living in different communities (45,46). Once these social institutions were established, males would be in a position to recognize these individuals as potential coalitionary partners for aggressive or lethal purposes and could use warfare as a vehicle to vet potential social partners for marriage exchange.…”

“…However, qualitative differences exist between the two species (8,31,43). Chimpanzees form no broader coalitions beyond the local community, but humans demonstrate a unique form of multitiered social structure in which marriage, social kinship, alliances, trade, and communication bond multiple descent groups, residential communities, and even ethnolinguistic units (32,(44)(45)(46)(47). Human metagroup social structure involves a concomitant increase in cooperation and competition in wider networks that extend beyond the local community (45,46).…”

“…Chimpanzees form no broader coalitions beyond the local community, but humans demonstrate a unique form of multitiered social structure in which marriage, social kinship, alliances, trade, and communication bond multiple descent groups, residential communities, and even ethnolinguistic units (32,(44)(45)(46)(47). Human metagroup social structure involves a concomitant increase in cooperation and competition in wider networks that extend beyond the local community (45,46). A wide net of social ties enables the formation of coalitions pitted against other groups in cycles of ongoing violence (1,20,48,49), motivated by a variety of factors (21), and generating multicommunity conflicts at scales unparalleled by other species (50).…”

What do men want? Re-examining whether men benefit from higher fertility than is optimal for women

“…Nearly all human societies allow individuals of at least one gender to remarry, minimally upon the death of their spouse, which can decouple the spouses' reproductive interests and thus increase conflicts insofar as this increases men's or women's outside options. However, humans have also experienced selection towards long-term monogamous pair-bonding that should lower such sexual conflicts [18]. In these long-term pair bonds, a man suffers from his partner's costs of reproduction-e.g.…”