This study investigates the relationship between societal complexity and familial complexity. Results suggest that the relationship is somewhat curvilinear; that is, in simpler societies more societal complexity is associated with a larger familial system, but the most developed societies have smaller familial systems. The demographic, economic, and politcal correlates of maximum family size are discussed.

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.

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 study examines why conflict emerges and how societies resolve it. The authors posit that increasing societal scale and differentiation create more potential for conflict but also more complex forms of conflict resolution. Analysis supports this theory, showing that measures of cultural complexity are positively associated with legal mechanisms for conflict resolution.

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.

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.

This study tests the relationship between population pressure and social evolution in agricultural societies. The author predicts that population pressure will be positively related to the evolution of descent, political integration, and class stratification. Results support this prediction.

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.

Researchers examine marriage patterns of 186 societies from the Standard Cross-Cultural Sample (SCCS). The eleven predictor variables are pathogen stress, arranged female marriages, population density, father roles during infancy, temperature, social stratification, wealth inequality, internal warfare, assault frequency, female agricultural contribution, and sex ratio. The two outcome variables measuring polygyny are cultural rules constraining polygyny and the percentage of married men who are polygynous. Controlling on phylogeny using a global supertree of the languages, analysis of marriage patterns reveals that assault frequency and pathogen stress are the strongest predictors of polygyny. These findings offer additional support for the theories of harem-defense polygyny and male genetic quality.

The researcher predicts a positive association between prevalence of homosexuality and agricultural and pastoral subsistence types, reasoning that higher frequency of arranged marriages among agropastoral societies will lessen negative selection pressure on genes which encode for non-exclusive heterosexual orientation. Findings appear to support the prediction.