The authors develop and empirically test a model in which exogamy is negatively predicted by community size, due to decreasing heterogeneity from endogenous marriages in small settlements, and positively predicted by disparity in productivity between communities which is 'smoothed out' by transfer of community members through exogamous marriages. Support for both predictions is found, which is used to argue that cultural traits like marriage customs are heavily influenced by population-environment relationships.

Prior research by Oswalt (1973, 1976) and Torrence (1983, 2001) has suggested that risk of resource failure is a significant predictor of toolkit complexity and diversity among hunter-gatherers. In this paper, the same relationship is tested among small-scale herding and farming groups. However, no significant correlation is discovered between any measure of resource risk and any measure of toolkit complexity. The researchers suggest that this absence may be the result of greater reliance on non-technological diversification methods among farmers (i.e. spatial diversification, mixed farming, intercropping), or of other unaccounted-for sources of risk (i.e. intergroup raiding and warfare).

This study examines socio-economic predictors of political complexity. Findings suggest that class stratification is the most significant predictor of political complexity.

In the field of bioacoustics, the Acoustic Adaptation theory suggests that variation in vocalization across different species can be accounted for by the acoustic properties of different habitats. Here, the researchers test consonant- and vowel-heaviness in human languages against various environmental variables in order to examine the theory's potential application to our own species. The authors identify a significant negative correlation between consonant heaviness and temperature, precipitation, and tree cover, and some positive correlation with rugosity and elevation as their most important findings, while acknowledging the potentially influential roles of migration and demographic factors in producing this relationship.

This article focuses on the effect of environmental extremes and unpredictability on human behavior and reproductive strategies. Significant correlations were found between environmental extremes and unpredictability and several variables, including mobility, subsistence mode, and degree of polygyny.

In this study, the authors examine pathways to social inequality, specifically social class hierarchy, in 408 non-industrial societies. In a path model, they find social class hierarchy to be directly associated with increased population size, intensive agriculture and large animal husbandry, real property inheritance (unigeniture) and hereditary political succession, with an overall R-squared of 0.45. They conclude that a complex web of effects consisting of environmental variables, mediated by resource intensification, wealth transmission variables, and population size all shape social inequality.

The authors test the relationship between ethnolinguistic area and various environmental variables in a cross-cultural sample of hunter-gatherer, pastoral, and agricultural subsistence groups in order to evaluate various hypotheses surrounding the geographic and ecological origins of cultural diversity. They propose that societies which adopted agriculture at the beginning of the Holocene were less directly affected by climate which, combined with the effect of increasing political and cultural complexity, allowed coordination and homogenization of ethnolinguistic groups over a broader swathe of territory.

The second and third parts of this book classify the economic systems of foraging and agricultural societies in the SCCS based on correlations between their institutions of property an distribution. These economic types are then examined for relationships with other social, political, demographic, and environmental factors in order to draw tentative conclusions regarding the origins of the Agricultural and Industrial Revolutions. The fourth part of the book uses cross-national data to examine similar associations in industrial/service economies, and is not included here.

This article tests several hypotheses related to the presence or absence of polygyny. Results suggest a negative relationship between polygyny and male provisioning, and positive relationships between polygyny and warfare, interpersonal aggression, and pathogen stress.

This paper poses and tests relationships between local spatial variability of rainfall and property rights, as well as the degree of hierarchy, across 41 different tribal societies in Sudan. The authors find that there is a significant negative relationship between rainfall variability and degree of hierarchy. They also find that in the presence of local rainfall variability in Sudan, members of a tribe are more likely to establish common property institutions that allow access to all members.