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.

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.

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).

This article tests a series of hypotheses differentiating internal warfare and external warfare. Results support the theory that internal warfare is a population control mechanism more common in patrilocal societies, whereas external warfare occurs between two societies, one of which recently migrated and adopted matrilocal residence. Based on these findings, the authors assert that internal warfare can be regulated while external warfare cannot.

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.

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 examines the relationship between warfare and trade and concludes that the relationship varies within different levels of political organization.

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).

This book examines the characteristics of warlike and warless foraging societies, as well as the transitional stages that occur when a society becomes warlike. Several predicted correlates of warfare frequency are supported.

This study investigates the presence of feuding, arguing that a solely evolutionary or functional approach misses important inter-societal factors. Results indicate that while fraternal interest groups are associated with feuding, the presence of war and level of political integration also increase the likelihood of feuding.