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Postmarital residence patterns in traditional human societies figure prominently in models of hominid social evolution with arguments for patriocal human bands similar in structure to female-dispersal systems in other African apes. However, con- siderable flexibility in hunter-gatherer cultures has led to their characterization as primarily multiocal. Horticulturalists are associated with larger, more sedentary social groups with more political inequality and intergroup conflict and may therefore provide additional insights into evolved human social struc- tures. We analyze coresidence patterns of primary kin for 34 New World horticultural societies (6,833 adults living in 243 residential groupings) to show more uxoniocality (women live with more kin) than found for hunter-gatherers. Our findings further point to the uniqueness of human social structures and to considerable variation that is not fully described by tradi- tional postmarital residence typologies. Sex biases in coresident kin can vary according to the scale of analysis (household vs. house cluster vs. village) and change across the life span, with women often living with more kin later in life. Headmen in large villages live with more close kin, primarily siblings, than do nonheadmen. Importantly, human marriage exchange and residence patterns create meta-group social structures, with alliances extending across multiple villages often united in competition against other large alliances at scales unparalleled by other species. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the life history consequences of density dependence and the evolution of human body size. The researchers used an approach focusing on two concurrent pathways leading to human body size reduction including density-dependent responses to resource scarcity and selection for rapid development in the face of high extrinsic mortality rates. The results support density-dependent effects on body size that act through two pathways including nutritional constraints and juvenile mortality contributing to a nearly twofold range in body size across human societies.

Human societies share a large number of complex social traits relating to kinship, which together constitute what is called here the human kinship configuration. I use a comparative phylogenetic approach to show that each of the traits making up that configuration has an evolutionary history and hence a biological foundation. The origin of many complex traits may be explained in terms of emergent products of the combination of more elementary features present in other primate species, whereas other traits appear to emerge from the combination of primate features with uniquely human cognitive abilities. The resulting composite traits thus have a compounded biological foundation, but at the same time they are always manifest under specific cultural--formal and semantic--expressions in any society. The traits may thus be seen as open-ended, culturally polymorphic and polysemous categories, or sociocultural categories, with the categories themselves having a biological foundation while their contents are culturally defined. Importantly, those categories need not be cross-culturally universal even though they are natural; their presence or absence in a given society is culturally modulated. I argue that a large number of such categories operate as an interface that helps bridge the gap between human biology and the sociocultural realm and that information on that interface is required for understanding how human nature structures cultural diversity. [ABSTRACT FROM AUTHOR]

Hypotheses on the benefits of the practice of partible paternity are tested using demographic data for Ache foragers of Paraguay. Partible paternity refers to the institution of multiple males considered to contribute to the conception of a single offspring. Analyses focus on patterns of primary and secondary co-fatherhood among men, genealogical relationships between co-fathers, and relation between band co-residence and co-fatherhood. Results indicate that men who had more secondary fatherhood also had more primary fatherhood; co-fathers are more closely related, on average, than men who are not co-fathers; and co-fathers were also more likely to reside together than men who were not co-fathers, even after controlling for relatedness. Results are most consistent with women choosing co-fathers of offspring in ways that maximize likelihood and amount of investment (multiple investors hypothesis) and men competing for more mates with at least partially affiliative outcomes (mate competition and male alliance hypotheses). [ABSTRACT FROM AUTHOR]