Living with Kin in Lowland Horticultural Societies

Walker, Robert; Beckerman, Stephen; Flinn, Mark V.; Gurven, Michael; Rueden, Chris R. von; Kramer, Karen L.; Greaves, Russell D.; Córdoba, Lorena; Villar, Diego; Hagen, Edward H.; Koster, Jeremy; Sugiyama, Lawrence S.; Hunter, Tiffany E.; Hill, Kim

doi:10.1086/668867

Cited by 47 publications

(41 citation statements)

References 34 publications

(42 reference statements)

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“…The latter finding is consistent with research demonstrating that Yanomamö men have a preference for coresiding with close genetic kin, especially brothers (86). Although social and genetic kinship play a pivotal role in within-community alliance formation (87,88), unokai alliances seem to be more salient for uniting multiple lineages and villages.…”

Section: Discussionsupporting

confidence: 86%

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

Macfarlan

Walker

Flinn

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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114

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Some cross-cultural evidence suggests lethal coalitionary aggression in humans is the product of residence and descent rules that promote fraternal interest groups, i.e., power groups of coresident males bonded by kinship. As such, human lethal coalitions are hypothesized to be homologous to chimpanzee (Pan troglodytes) border patrols. However, humans demonstrate a unique metagroup social structure in which strategic alliances allow individuals to form coalitions transcending local community boundaries. We test predictions derived from the fraternal interest group and strategic alliance models using lethal coalition data from a lowland South American population, the Yanomamö. Yanomamö men who kill an enemy acquire a special status, termed unokai. We examine the social characteristics of co-unokais or men who jointly kill others. Analyses indicate co-unokais generally are (i) from the same population but from different villages and patrilines, (ii) close age mates, and (iii) maternal half-first cousins. Furthermore, the incident rate for co-unokai killings increases if men are similar in age, from the same population, and from different natal communities. Co-unokais who have killed more times in the past and who are more genetically related to each other have a higher probability of coresidence in adulthood. Last, a relationship exists between lethal coalition formation and marriage exchange. In this population, internal warfare unites multiple communities, and co-unokais strategically form new residential groups and marriage alliances. These results support the strategic alliance model of coalitionary aggression, demonstrate the complexities of human alliance formation, and illuminate key differences in social structure distinguishing humans from other primates.internal warfare | male coalitions | fraternal interest groups | strategic alliances | Yanomamö T he evolution of lethal coalitionary aggression remains a pivotal topic across the biological and social sciences (1-12). Revealing the ultimate and proximate factors responsible for the emergence and dynamics of warfare is of practical and theoretical importance across a wide range of contexts, including the evolution of human ultra-sociality, coalitionary psychology, ethnic identity, leadership, and political behavior. Surprisingly few detailed analyses exist concerning the social composition of lethal coalitions in small-scale societies. This lack is problematic, because the particular form that lethal coalitions take sheds light on the adaptive function of this behavior and the phylogenetic roots of coalitionary aggression with chimpanzees (Pan troglodytes).Humans, like chimpanzees, demonstrate a capacity to coordinate behavior with others to kill conspecifics (11)(12)(13)(14)(15). Although the scope of lethal coalitionary aggression is far greater in humans, a number of similarities exist between the two species, namely coordinated groups of adult males defending home territories and aggressing against individuals from other communities with low-cost but ...

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Section: Discussionsupporting

confidence: 86%

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

Macfarlan

Walker

Flinn

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

114

View full text Add to dashboard Cite

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“…Cross-culturally, older adults often fill leadership roles, in part because they have had more time to accrue such knowledge (Silverman and Maxwell 1978; Simmons 1945). Older individuals will also have more social support from adult offspring and other kin; individuals with the most kinship ties to other group members tend to hold leadership positions in traditional societies (Chagnon 1979; Hughes 1988; Walker et al 2013). However, age-related decline in physical condition can be detrimental to leadership acquisition, which is why older but not necessarily the oldest individuals are favored as leaders.…”

Section: What Traits Are Preferred In Leaders?mentioning

confidence: 99%

Leadership in an Egalitarian Society

Rueden

Gurven

Kaplan

et al. 2014

Hum Nat

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162

177

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Leadership is instrumental to resolution of collective action dilemmas, particularly in large, heterogeneous groups. Less is known about the characteristics or effectiveness of leadership in small-scale, homogeneous, and relatively egalitarian societies, in which humans have spent most of our existence. Among Tsimane’ forager-horticulturalists of Bolivia, we (1) assess traits of elected leaders under experimental and naturalistic conditions and (2) test whether leaders impact collective action outcomes. We find that elected leaders are physically strong and have more kin and other exchange partners. Their ranks on physical dominance, kin support, and trustworthiness predict how well their groups perform, but only where group members have a history of collaborative interaction. Leaders do not take more of the spoils. We discuss why physically strong leaders can be compatible with egalitarianism, and we suggest that leaders in egalitarian societies may be more motivated by maintaining an altruistic reputation than by short-term rewards of collective action.

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“…While human dispersal was traditionally portrayed as being male-biased, the model of the patrilocal band (Radcliffe-Brown 1930;Service 1962;Steward 1955) has long been questioned (Ember 1975;Helm 1965;Hiatt 1962;Lee 1972Lee , 1979Lee and DeVore 1968;Meggitt 1965;Murdock 1949;Shapiro 1973;Turnbull 1965). Matrilocality generally has been considered less prevalent among huntergatherers (Walker et al 2013) and is associated with particular activities resulting in male absenteeism, such as external warfare (Divale 1974;Ember and Ember 1971), long distance hunting (Perry 1989) and reliance on female subsistence (Scelza and Bliege Bird 2008). A number of recent case studies have pointed out that residence patterns among foragers are flexible, facultative and may vary across the life course (Blurton Jones et al 2005;Marlowe 2010).…”

Section: Hunter-gatherer Residencementioning

confidence: 99%