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.

This article investigates incest rules, proposing that they are instituted by rulers as a way of preventing wealth-concentration among non-ruling families. Three hypotheses are derived and supported with empirical analysis. Two alternative evolutionary hypotheses are discussed and dismissed by the author.

This article presents a theory of evolutionary development of incest regulation, namely that as societal complexity increases the incest taboo will become less extensive. The author presents empirical support for this theory, though the association is not supported among simply structured societies. The role of descent type is also discussed.

This article uses alliance theory and kin selection theory to examine the relationship between consanguineous marriage and descent system. The author argues that there is no relationship between the severity of incest taboos and the rules of exogamy or endogamy. A series of testable hypotheses regarding incest, marital, and descent rules are presented.

This book is a comprehensive analysis of many aspects of social structure including family, clan, community, kinship terminology, social organization, regulation of sex, incest taboos, and sexual choice.

While it is widely accepted that there are a multitude of variables that contribute to a society’s level of democracy, the authors of this study argue that the prevalence of consanguinity is one that is often overlooked. Using a sample of 70 nations, they tested the relationship between consanguinity (defined as marriage and subsequent mating between second cousins or closer relatives) and level of democracy (defined by both the Polity IV scale and the EIU Index) and found a significant negative relationship. Similarly, when controlled for a host of different variables in multiple regression analysis, the significant relationship between consanguinity and level of democracy held true.

This book examines male and female power in various kinship configurations. Variables for male dominance and female autonomy are associated with various political and social variables, such as political complexity and co-wife jealousy. Several hypotheses are supported.

Authors examine suicidality within small-scale non-industrial societies. They use ethnographic data to test two models: deCatanzaro's inclusive fitness model and the bargaining model (suicide attempts as a costly signal of need). Limited support is found for deCatanzaro's inclusive fitness model while strong support is found for the bargaining model. Support for deCatanzaro's inclusive fitness model increased with increasing latitude; authors suggest that in climactically-harsher environments, in which elderly or infirm individuals may impose a higher burden on kin, completed suicide occurs more because it might increase inclusive fitness. Fit of and support for each model were differentially age-dependent.

The researchers examine associations between male status and various measures of reproductive success among foraging/non-foraging, and monogamous/polygynous societies in order to test the "egalitarian hypothesis" which predicts lower status effects in hunter-gatherer groups. Contrary to this hypothesis, they find that male social status is equally significantly associated with reproductive success in foraging and nonforaging societies. Additional support is found for the "mating effort" hypothesis, which predicts that male reproductive success will be more associated with fertility than offspring mortality in polygynous societies, leading the authors to make various suggestions regarding the evolutionary mechanisms at play.

The author performs tests of hypothesized relationships between arranged marriage and various forms of non-sanctioned mate choice. Overall, the author theorizes that where marriages are arranged, mate choice will be found in higher prevalence of premarital sex, extramarital sex, and rape. Most tests support these relationships in the hypothesized directions, suggesting that strict regulation of marriage provides parents with some, but far from complete control over the mate choice of their offspring.