This article examines marital residence and sibling coresidence among horticulturalists in the South American lowlands. The authors reject a hypothesis that patrilocality is the defining trait of Amazonian tropical forest culture. Results on horticulturalists are compared with findings on hunter-gatherers: horticulturalists tend to be more uxorilocal. Empirical analysis also suggests that women tend to live with more kin later in life, and in large villages headmen live with more kin than nonheadmen.

This study attempts to reconstruct ancestral marriage practices using hunter-gathers' phylogenies based on mitochondrial DNA sequences. Data suggest that arranged marriages and brideprice/bridewealth likely go back at least to the first modern human migrations out of Africa and that early ancestral human societies probably had low levels of polygyny.

This study examines instances of group fission cross-culturally. Results suggest that internal political conflict and resource scarcity are the two most common causes of group fission. Results also suggest that group fission tends to occur along kin lines.

The authors examine degree of intensiveness (kin-relatedness) among foraging and agropastoralist societies, predicting that hunter-gatherers will pursue more extensive kinship networks in order to maximize residential options in the case of unpredictability or uneven geographic distribution of food resources. Support is found for the hypothesis, and it is suggested that while extensive fission-fusion dynamics are beneficial in foraging systems, the increase in cooperation in large-scale agricultural settlements is aided by norms which encourage kin marriage and relatedness.

The present research examines the residence patterns of 34 hunter-gatherer societies and 34 lowland South American horticulturalist societies using census data. Contrary to the traditional view of patrilocal postmarital residence being prevalent, the present findings suggest more multilocality in residence patterns for hunter-gatherer and horticulturalist societies. The author concludes that hunter-gatherers are slightly patrilocal and horticulturalists slightly matrilocal.

The authors predict that fitness outcomes will be negatively associated with spousal relatedness among foragers but positively associated among non-foragers, due to the greater social benefits of intensive kinship systems among non-foragers. Support is found for this hypothesis; however, an interaction effect is discovered with inbreeding, which appears to account for the variability in these relationships independent of subsistence activity. The authors qualify this support in order to explain why the incidence of cousin-marriage in non-foraging societies is not higher.

Using a representative sample of 339 hunter-gatherer societies, researchers examine the relationship between hunter-gatherer use of space, size of population and supply of resources to see if they are similar to other organisms. By combining all factors into a single model, the authors claim to explain 86% of the variation in home range. Hunters have greater resource distribution than gatherers but both more so than aquatic foragers. Lastly, terrestrial foragers have more extensive home ranges than aquatic foragers.

Authors use genealogical data to investigate pair bond stability and reproductive skew across a sample of 80 small-scale societies. Results suggest that male reproductive skew and pair-bond stability are independent sources of cross-cultural variation in human mating patterns.

The biological success derived from cumulative culture and cooperation and their association with ancestral group structure is examined. It is suggested that inclusive fitness cannot explain extensive cooperation in hunter-gatherers because in most of the foraging societies examined, most individuals in residential groups are unrelated. These large social networks may explain why humans are capable of social learning.