In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.

In this paper, the authors argue that polygyny creates social inequality in which economically advantaged men marry multiple women and economically disadvantaged men marry late in life or potentially never. The institution of polygyny results in a higher proportion of single men without families ("excess men"), who, the authors propose, may turn to violence to achieve higher wealth or prestige. Following this theory, the authors hypothesize that societies with more polygynous neighbors will be at higher risk for intergroup conflict, for which they find robust support. They also find that young men in polygynous societies, who are more likely to be economically disadvantaged and have less prestige, are also more likely to feel as though they are treated unequally and more ready to resort to violence, supporting the authors' theorized underlying mechanism.

In this article, the authors explore cultural variables that they propose contribute to the maintenance of peace in non-warring societies. These variables are compared in 16 peaceful systems (as coded by the authors from anthropological and historical data) and in 30 warring societies taken from the Standard Cross-Cultural Sample (SCCS). Findings associate more peaceful cultures with peace systems, and non-peaceful cultures with warring societies.

This book examines the difference between warless and warlike societies and attempts to determine the point at which a society becomes warlike. The author suggests that differences between warless and warlike societies are mostly organizational and hypothesizes that "unsegmented" societies, or societies that have a weaker sense of group identity and cohesion, will be more likely to be warless than "segmented" societies. Several tests are presented. Results generally support the hypothesis.

This article offers an exploratory study of the fitness costs of warfare on women. The author examines stories of inter-group conflict cross-culturally and finds that warfare exerts significant selection pressure on women, such as killing or capturing women, or killing their offspring or mate. The author suggests that future research should examine female cognition in relation to these selective pressures.

This book takes a cross-cultural, cross-historical approach to the study of military deterrence. Political, economic, and geographic correlates are considered, particularly military and diplomatic strategy. Several hypotheses are tested and some are supported.

Given that research on female political representation tends to be overlooked across many societies, this study investigates whether historical female political leadership influences contemporary female political representation in Africa. The authors hypothesize that precolonial traditions of women in leadership persist in shaping present-day representation. Using two original datasets—one from cross-cultural samples and one from previous elections—they find that ethnic groups with histories of female leaders have more women elected today, with results also show that many institutional factors have shaped women’s traditional political roles, and that the effects of historical colonialism have reversed much of their influence. The conclusion is that historical female leadership continues to affect modern representation, though shaped by institutional change.

This study examines pairwise differences between similar cultures in order to minimize cultural variation within the SCCS and reveal possible correlates of cultural complexity. Results suggest that one measure of complexity (government above the community level) is significantly associated with several other variables.

This article builds on previous cross-country and cross-state research into Tightness-Looseness (TL) theory, which proposes relationships between the incidence of ecological threat and cultural tightness, as well as tightness’ downstream effects on belief in a moralizing high god, inter-group contact and authoritarian leadership. To evaluate the generalizability of TL theory beyond complex cultures, the authors test these relationships among 86 nonindustrial societies from the ethnographic record. A structural equation model is presented of the results for nonindustrial societies; it is generally in accord with previous findings from more complex societies. Because the nonindustrial sample is more variable, they also look at relationships between societal complexity and kinship heterogeneity, aspects that vary in nonindustrial societies.

This article investigates whether external warfare, intercommunity trade, and female exogamy lead to more amicable intercommunity relationships. Intercommunity amicability is considered a historical facilitator of the large-scale integration of human groups. The absence of internal warfare is used as a measure for intercommunity amicability.