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Bands of brothers and in-laws: Waorani warfare, marriage and alliance formation.

ABSTRACT: The root of modern human warfare lies in the lethal coalitionary violence of males in small-scale societies. However, there is a paucity of quantitative data concerning the form and function of coalitionary violence in this setting. Debates exist over how lethal coalitions are constituted, as well as the motivations and benefits for males to join such groups. Data from a lowland Amazonian population, the Waorani of Ecuador, illuminate three issues: (i) the degree to which raiding parties are composed of groups of fraternal kin as opposed to strategic alliances of actual or potential affinal kin; (ii) the extent to which individuals use pre-existing affinal ties to motivate others to participate in war or leverage warfare as a mechanism to create such ties; and (iii) the extent to which participation in raiding is driven by rewards associated with future marriage opportunities. Analyses demonstrate that Waorani raiding parties were composed of a mix of males who were potential affines, actual affines and fraternal kin, suggesting that men used pre-existing genetic, lineal and social kin ties for recruiting raid partners and used raiding as a venue to create novel social relationships. Furthermore, analyses demonstrate that males leveraged raiding alliances to achieve marriage opportunities for themselves as well as for their children. Overall, it appears that a complex set of motivations involving individual rewards, kin marriage opportunities, subtle coercion and the assessment of alliance strength promote violent intergroup conflict among the Waorani. These findings illustrate the complex inter-relationships among kin selection, coalition building and mating success in our species.

SUBMITTER: Macfarlan SJ

PROVIDER: S-EPMC6235029 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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Bands of brothers and in-laws: Waorani warfare, marriage and alliance formation.

Macfarlan Shane J SJ Erickson Pamela I PI Yost James J Regalado Jhanira J Jaramillo Lilia L Beckerman Stephen S

Proceedings. Biological sciences 20181031 1890

The root of modern human warfare lies in the lethal coalitionary violence of males in small-scale societies. However, there is a paucity of quantitative data concerning the form and function of coalitionary violence in this setting. Debates exist over how lethal coalitions are constituted, as well as the motivations and benefits for males to join such groups. Data from a lowland Amazonian population, the Waorani of Ecuador, illuminate three issues: (i) the degree to which raiding parties are com ...[more]

PMID: 30381383

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Project description:BackgroundChild marriage in Malawi is a significant problem with 42.1% of women 20-24 married by age 18. In 2017 the Malawi government formalized legislation to make marriage under age 18 illegal; violators are subject to fines. While leveraging laws to reduce child marriage is common, the enactment of laws and their enforcement has led to some novel practices. One such practice observed in Malawi is marriage withdrawal, where the community intervenes when a child marriage has taken place to force the girl to return to her natal home.MethodsThis paper is a qualitative analysis of perceptions regarding marriage withdrawal. We conducted focus group discussions and in-depth interviews with married and unmarried adolescents, parents of adolescents, and key community members in Mangochi and Nkhata Bay. Data were collected as part of an evaluation of the More Than Brides Alliance program aimed at delaying marriage and improving access to sexual and reproductive health services in Malawi.ResultsThe knowledge that violation of marriage laws entails substantial fines is widespread and marriage withdrawals are seen by some respondents as a way of enforcing the spirit of child marriage laws while avoiding fines. Some respondents suggest that enforcement of marriage laws has an unintended effect of driving marriages underground. One important disconnect between the laws and the realities of child marriage practices in these communities is that the law holds parents responsible for the marriage and for preventing it, while parents do not necessarily exercise control, particularly when the marriage is precipitated by pregnancy. While parents and other adults view withdrawals as an acceptable resolution of a problematic child marriage, girls noted many drawbacks for withdrawn girls such as stigma and limited education and livelihood opportunities once withdrawn.ConclusionsOur exploration of perceptions about marriage laws suggest that the imposition of fines may have some unintended consequences, both driving the practice underground and encouraging practices to evade fines, and may be associated with unintended consequences for adolescent girls. Programs to address child marriage should include other approaches that address more distal drivers including poverty and lack of alternatives to child marriage.Trial registrationThis work is part of an RCT registered August 4, 2016 in the AEA RCT registry identified as: AEARCTR-0001463 . See: https://www.socialscienceregistry.org/trials/1463.

Project description:BackgroundArguably the most influential force in human history is the formation of social coalitions and alliances (i.e., long-lasting coalitions) and their impact on individual power. Understanding the dynamics of alliance formation and its consequences for biological, social, and cultural evolution is a formidable theoretical challenge. In most great ape species, coalitions occur at individual and group levels and among both kin and non-kin. Nonetheless, ape societies remain essentially hierarchical, and coalitions rarely weaken social inequality. In contrast, human hunter-gatherers show a remarkable tendency to egalitarianism, and human coalitions and alliances occur not only among individuals and groups, but also among groups of groups. These observations suggest that the evolutionary dynamics of human coalitions can only be understood in the context of social networks and cognitive evolution.Methodology/principal findingsHere, we develop a stochastic model describing the emergence of networks of allies resulting from within-group competition for status or mates between individuals utilizing dyadic information. The model shows that alliances often emerge in a phase transition-like fashion if the group size, awareness, aggressiveness, and persuasiveness of individuals are large and the decay rate of individual affinities is small. With cultural inheritance of social networks, a single leveling alliance including all group members can emerge in several generations.Conclusions/significanceWe propose a simple and flexible theoretical approach for studying the dynamics of alliance emergence applicable where game-theoretic methods are not practical. Our approach is both scalable and expandable. It is scalable in that it can be generalized to larger groups, or groups of groups. It is expandable in that it allows for inclusion of additional factors such as behavioral, genetic, social, and cultural features. Our results suggest that a rapid transition from a hierarchical society of great apes to an egalitarian society of hunter-gatherers (often referred to as "egalitarian revolution") could indeed follow an increase in human cognitive abilities. The establishment of stable group-wide egalitarian alliances creates conditions promoting the origin of cultural norms favoring the group interests over those of individuals.

Dataset Information

Bands of brothers and in-laws: Waorani warfare, marriage and alliance formation.

Publications

Bands of brothers and in-laws: Waorani warfare, marriage and alliance formation.

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