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 uses signaling theory and tests for a relationship between costly male rites and frequency of warfare.

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.

Textor summarizes cross-cultural male initiation rites findings pertaining to cultural, environmental, psychological, and social phenomena.

This article examines the relationship between pathogen stress and polygyny. Results indicate that there is a positive association between the two that is not confounded by geographic region, latitude, population density, male-male competition, or presence of brideprice. In particular, pathogen stress precicts higher levels of non-sororal polygyny and capturing women for wives or concubines.

This chapter examines the role of male and female ornamentation. Several hypotheses concerning mating systems and ornamentation are empirically tested; several are supported.

The author reanalyzes hypotheses proposed by Lomax et al. (1968) that are based on Lomax's collection of cantometric data. Considering historical/regional variables, the author suggests that difusion and common history better explain certain musical features such as wordiness than functional and evolutionary processes. However, other Lomax findings are supported involving interlocked, contrapuntal singing and narrow nasal-voiced singing.

This study is a comprehensive analysis of female and male genital mutilation/cutting (FGM/C and MGM/C) practices, including their history and socio-ecological correlates, using a phylogenetic cross-cultural framework. It employed two global ethnographic samples, the Ethnographic Atlas (EA) and the Standard Cross-Cultural Sample (SCCS), and two subsets of the phylogeny (supertree) of human populations based on genetic and linguistic data, to investigate the variables that may have led to the introduction of these practices, and to determine where and when they may have originated. The study suggests that MGM/C probably originated in polygynous societies with separate residence for co-wives, supporting a mate-guarding function, and that FGM/C likely originated subsequently and almost exclusively in societies already practicing MGM/C, where it may have become a signal of chastity. Both practices are believed to have originated multiple times, some as early as in the mid-Holocene (5,000–7,000 years ago). The study posits that GM/C co-evolves with and may help maintain fundamental social structures and that the high fitness costs of FGM/C are offset by social benefits, such as enhanced marriageability and social capital.

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 chapter attempts to explain why the number, importance, and duration of food and sex taboos during pregnancy vary cross-culturally. The author hypothesizes that differences in child socialization will be associated with differences in food taboos, and differences in sexual behavior and sanctions will be associated with sex taboos. Results support the hypotheses.