The authors construct a mathematical model from which they generate their main hypothesis that resource unpredictability should be associated with frequency of warfare. A cross-cultural test of this hypothesis was performed by Ember and Ember (1992). The authors critique these findings for state societies and test and alternate hypothesis for application to state societies.

In this article, the authors reevaluate Carneiro's (1970) circumscription theory of state formation. They do this by examining relationships between the degree of political hierarchy and whether warfare is conducted for conquest, land acquisition, or plunder. While they find evidence that this theory is plausible in some situations, there is not enough to support the theory wholesale. Thus, they suggest that other theories of state formation should be investigated.

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

This study tests a hypothesis developed in a previous study (Artemova 2003). The authors analyze the relationship between the monopolization of politically important information and gender inequality. Sixty correlations are tested between measures of female status and an indicator of information monopolization; findings support the hypothesis.

Controlling for community type, the researchers examine a potential relationship between family size (nuclear vs. extended) and communal leadership (hereditary vs. elected) in an effort to suggest potential predictors of hierarchical structures in societies. They claim support for their hypothesis that societies with nuclear families will be more likely to have democratic communal leadership, across four different community types.

This study analyzes the relationship between communal democracy and family size. Results show a weakly significant negative correlation between communal leadership and family size. Authors suggest that this relationship could be challenged based on the known curvilinear relationship between family size and cultural complexity. However, several further tests suggest that there are grounds for maintaining that family size has some independent influence on the existence of communial democracy.

Theories about the relationship between warfare, militarism, male dominance and authoritarianism are tested.

The article tests theories that may explain why warfare frequency varies from society to society. The focus is on ecological problems, particularly different kinds of resource scarcity, but social and psychological theories are also tested with both bivariate and multivariate analyses. Because unpredictable disasters are such a strong predictor in nonstate societies, the authors theorize that war may mostly be caused by a fear of nature.

The study examines the relationship between communal democracy and family size. The results indicate a weak significant negative correlation between communal leadership and family size. Even though the researchers suggest that the known curvilinear relationship between the variables could challenge this finding, further tests indicate that there are grounds for maintaining that family size has some independent influence on the existence of communal democracy.

The present study attempts to replicate the Ember, Ember, and Russett (1992) worldwide finding that fighting rarely occurs between democracies in a sample of eastern African societies. Following the earlier study, the authors considered internal warfare to be an analog of international warfare and measures of political participation analogous to democracy. The researchers also explore if there is an association between political participation and committing atrocities. Contrary to past findings, internal warfare was not predicted by the same set of variables as the 1992 study, but there is an inverse relationship between committing atrocities and political participation. However, when additional variables were added, internal warfare was significantly predicted by less political participation.