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.

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 paper suggests that polygyny may be best explained by uneven sex ratios, particularly an excess of women while men are engaged in warfare. The author also considers Whiting’s 1964 theory that used post-partum sex taboos to explain polygyny. These two theories are tested cross-culturally and results suggest that polygyny is a response to an unbalanced sex ratio in favor of women.

"This paper describes how the "sex-ratio" explanation of polygyny compares with some alternative, supposedly causal explanations. The results suggest that polygyny is best predicted by two statistically independent factors--high male mortality in warfare…and delayed age of marriage for men."

This article uses logistic regression analysis to examine pathogen stress and male mortality in warfare as predictors of nonsororal polygyny. Differences between state and non-state societies are observed. The authors also retest variables from White and Burton's 1988 study on causes of polygyny, finding only fraternal interest groups and absence of plow significant.

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.

This article uses factor analysis to identify the key variables underlying the many cross-cultural associations reported by Textor (1967). Twelve factors are identified.

This study examines how social structure, political organization, and intersocietal relations may affect the incidence of internal warfare (between culturally similar political communities). Results show that in uncentralized political systems, fraternal interest groups and unauthorized raiding parties may increase the incidence of internal war.

This article presents two evolutionary models that may explain relationships between war and socialization of children: the "environmentally contingent reproductive strategy" (ECRS) model put forward by Draper and Harpending (1982), and a model put forward by Carol and Melvin Ember. Results do not provide support for the hypotheses involving father-infant sleeping proximity derived from the ECRS model. The authors also find some inconsistencies with their own model.

This article suggests a general theory of conflict and violence that may help explain the conditions under which internal conflict co-occur or are differentiated.