This book investigates the evolution of military organizations and their activities. Hypotheses frequently relate military organizations to political variables. Data suggested that more politically centralized societies have more sophisticated military organizations which are more likely to be successful in conflict (though military sophistication does not appear to deter attack).

The author presents a comprehensive study on the prevalence, presentation, and motivation of the "ultimate coercive sanction": capital punishment, or the "death penalty". He begins by examining capital punishment across all 53 cultures for which data was present in the Probability Sample Files, and finds that capital punishment is overwhelmingly present. After discerning some general trends, the author examines how capital punishment presents itself across different kinds of political systems, and uses the results to voice support for various theories on why the capital punishment is practiced. The study concludes by stating that the capital punishment may be something that human society may never be truly rid of, but greater societal stability may be able to reduce its prevalence.

An early cross-cultural study that sought to establish correlations between "stages" of economic culture and a variety of different social and political institutions, such as form of government and justice, marriage and kinship, and behaviors during warfare.

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.

The author hypothesizes that physical violence is strongly related to the deprivation of physical pleasure. The author tests this hypothesis by looking at the relationship between physical affection towards infants, as well as attitudes towards premarital sex, and several variables related to violence. Results support the hypothesis.

This book examines naming practices cross-culturally. The author posits that naming practices help to both reflect and create conceptions of personal identity. Several correlations between name meanings and practices and various sociocultural variables are presented.

The present study tests the theory that intrasexual selection or male attraction may explain variation in male aggression in a sample of 78 societies. Measures of intrasexual selection include: male subsistence, male war mortality, polygyny, sex ratio, and wives variance. The authors claim support for the theory.

This study examines how social structure, political organization, and intersocietal relations may affect the incidence of internal warfare (between culturally similar political communities). Results show that in uncentralized political systems, fraternal interest groups and unauthorized raiding parties may increase the incidence of internal war.

Expanding on the author’s previous findings, this article examines the social and economic variables that may explain the cultural evolution of religious practitioners. With a 47 society sample, the author found that subsistence activities and socio-political conditions predict magico-religious practitioner types (sorcerers/witches, priests, shamanistic healers, mediums, healers, shaman/healers, and shamans) with the strongest results being from subsistence and political organization. He then used these findings to theorize about the biogenetic bases of religion in societies.

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.