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 paper reviews the results of the author's cross-cultural studies of war and aggression and their implications for prehistory.

In this study, the author empirically tests a formulation of Ellen Dissanayake's evolutionary theory of art, which argues that art evolved to promote group cohesion. The hypotheses derived from this theory and tested in this study specifically focus on ritual art and its relationships to various proxies for group cohesion such as community conflict and internal warfare. Results show that the presence of ritual art is significantly higher where certain measures of group cohesion are also higher (including lower internal warfare, lower conflict between communities of the same society, and lower frequency of violent conflict between groups within local communities).

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 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 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.

An extension of the author's 1993 study, An Archaeological Correlate of War, this study examines the relationship between community permeability and war in the ethnographic record using Naroll's study on household and population as a model with the aim of making inferences to the archaeological record.

This study retests the data presented by Sillitoe (1977) in his study of the relationship between likelihood of warfare and population density in New Guinea. Contrary to Sillitoe, the author finds a strong and significant association between the two variables. The author also finds a significant relationship between the severity of food shortages and the frequency of warfare cross-culturally.

The author builds upon previous research (Winkelman 1998) to further elucidate the cross-cultural predictors of institutionalized human sacrifice. The author considers a range of ecological factors and political variables, particularly geopolitical dynamics and intra- and inter-group relations. Other factors were explored, including social complexity and social structures. The author identifies the lack of an effective superordinate political authority as a main determinant in similar behaviors contemporarily (e.g. suicide bombers, beheadings, public brutality in civil war).

Author proposes and presents evidence in support of the theory that most societies practice virilocal or patrilocal residence (this is the "normal" pattern" and that matrilocal residence is adopted when societies migrate to an already populated area.