This study is a comprehensive analysis of female and male genital mutilation/cutting (FGM/C and MGM/C) practices, including their history and socio-ecological correlates, using a phylogenetic cross-cultural framework. It employed two global ethnographic samples, the Ethnographic Atlas (EA) and the Standard Cross-Cultural Sample (SCCS), and two subsets of the phylogeny (supertree) of human populations based on genetic and linguistic data, to investigate the variables that may have led to the introduction of these practices, and to determine where and when they may have originated. The study suggests that MGM/C probably originated in polygynous societies with separate residence for co-wives, supporting a mate-guarding function, and that FGM/C likely originated subsequently and almost exclusively in societies already practicing MGM/C, where it may have become a signal of chastity. Both practices are believed to have originated multiple times, some as early as in the mid-Holocene (5,000–7,000 years ago). The study posits that GM/C co-evolves with and may help maintain fundamental social structures and that the high fitness costs of FGM/C are offset by social benefits, such as enhanced marriageability and social capital.

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 identifies several methodological errors in the original study or moralizing gods by Roes and Raymond (2003) and presents new multiple regression model. Results suggest that a belief in moralizing gods is spread though cultural transmission, but it is also associated with conditions such as lower agricultural potential and lower external warfare. The authors theorize that moralizing gods have functional purposes such as bolstering property rights or maintaining social hierarchy.

"Seven of Max Weber's ideal-typical specifications for 'rational bureaucracy' are reformulated as a system of three 'bureaucratic' and four 'rational' variables. It is proposed that (a) bureaucratic variables are positively associated; (b) rational variables are positively associated; but that (c) rational variables are negatively associated with bureaucratic variables." Hypotheses are supported.

Using a sample of 313 societies classified within 24 language phyla, authors put forward a statistical model based on climate data [specifically focused on the 10°C (50°F) winter temperature isotherm] to explain why dispersion of preindustrial language phyla is remarkably homogeneous even despite heterogeneous geographical dispersion of sampled preindustrial cultural groups. They suggest that temperature has been a barrier to migration.

The researchers recode Broudeand Greene's (1976) SCCS data in order to distinguish between 'rare and absent' and different types of culturally-mediated same sex behavior, and to expand available data by including documents outside the SCCS. Their procedure suggests that androphilia is present in 57.5 - 83.6% and same-sex behavior present in 91.1% of all societies. They argue that these new data qualify androphilia as a context-dependent human universal, defined by Chapais (2014) as "patterns of behaviors that invariably or consistently arise in specific social circumstances in some cultures or population segments." (Hames et al. 69)

In this article Hames addresses the long-standing disagreements between evolutionary theories regarding human warfare (more specifically between Rousseauian and Hobbesian frameworks). This study posits that while most current and previous research focuses on the discrepancies between the frequency and intensity with which warfare takes place between hunter-gatherer and large-scale societies, the ability for societies to live in peace with their neighbors despite the possibility for warfare, is the most important evolutionary trait. Coexisting peacefully is what distinguishes human socially and politically from chimpanzees whereas warfare itself is a more primitive trait humans share with previous ancestors. Hames concludes that going forward, use of phylogenetic methods to control for common ancestry, and use of archaeological data would lead to new and more comprehensive findings. Although largely a review of principal warfare literature, Hames does present an original statistical finding on adult violence mortality which is reported below.

This article explores the following questions: What environmental and cultural factors might explain variation in prejudice across cultures? Do these factors explain the intention to vote for nationalist politicians? The authors perform seven studies, focusing on the link between cultural tightness and the rise of prejudice in cultures. They theorize that cultural tightness is positively correlated with the rise of prejudice against people perceived as disrupting the social order. From this theory, they suggest three hypotheses: 1) cultural variation in tightness is related to cultural variation in prejudice, 2) cultural tightness is related to the support for nationalist politicians, and 3) cultural tightness is a link between ecological threats and prejudice. The results support these hypotheses, offering a cultural evolutionary perspective on prejudice.

Researchers examined both why so many language are spoken today, and why they are so unevenly distributed geographically. Instead of looking at correlative tests, this study uses a process-based simulation model that attempted to predict both the number or precolonial languages in Australia as well as the number of languages per unit of land. The model was based upon three basic assumptions: 1) humans fill unoccupied spaces; 2) rainfall limits population density; 3) groups divide after reaching a maximum population. While researchers used the model strictly on the Australia continent, it was able to correctly explain 56% of spatial variation in language richness, and predict the total number of languages across the continent. The accuracy of this model concludes that climatic conditions and changes in group size are important factors in shaping language diversity patterns and therefore global human cultural diversity.

This article examines the conditions under which slavery occurs in preindustrial societies. Results suggest that social stratification and the existence of open resources are both necessary conditions for the occurrence of slavery.