Researchers looked at 180 of the 186 societies in the SCCS for changes over time in lineage systems. The goal was to estimate the frequency of transitions away from and to matriliny cross-culturally, as well as explore the potential causes of these patterns / transitions. The study focused on two overarching research questions: 1. How common are transitions away from matriliny and how often do ‘reverse transitions’ to matriliny occur? 2. What causes transitions to or from matriliny? Overall, the study found that transitions away from matriliny have been quite common within the time frames covered by the ethnographic samples available, while transitions from another system to matrility have been rare. In answering the second question, the researchers report the highest correlation is between subsistence transitions (towards pastoralism, intensive agriculture, or a market economy) and lineage transitions (away from matriliny) as well as between higher levels of social complexity (measured by stratification, slavery, and population size) and lineage transitions (away from matriliny).

The study is about matrilineal systems, where descent is traced along female lines. Matrilineal systems are relatively rare in human populations, and previous research has discussed the rarity and apparent instability of matriliny. The study aims to study the evolution of descent systems on a worldwide scale. The study tests for significant associations between matriliny and numerous cultural traits that have been theoretically associated with its stability or loss, such as subsistence strategy, animal domestication, mating system, residence pattern, wealth transfer, and property succession. Additionally, by combining genetic and linguistic information to build a global supertree that includes 16 matrilineal populations, the study also performs phylogenetically controlled analyses to assess the patterns of correlated evolution between descent and other traits.

This study focuses on the development of unilineal descent, reviewing previous theories and testing additional factors to explain the relationship between unilineal descent and unilocal residence. Results suggest four key factors leading to a low association between these two variables: insufficient alternatives to unilocal residence rule, instability of communal composition, absence of sedentary settlement pattern, and small average community size. A model linking all variables from the paper is presented.

Researchers examined kinships terminology systems for explanations regarding specifically observed typology of kin terms for cousins cross-culturally. They explore two theories, the first relating to population size via bottleneck evolution, and the second relating to social practices that shape kinship systems. Using the Ethnographic Atlas within D-PLACE, 936 societies with kinship system information were studied. The findings did not suggest a relationship between increased community size and a decrease in kinship complexity, however the research does suggest a relationship between practices of marriage and descent and kinship complexity.

This book is concerned with explaining variation in the status of women. The author, after measuring over 50 aspects of status, first concludes that status is not a unitary concept. Therefore the author looks at 10 different domains of status. Many traditional explanations are not supported; most support is found for the influence of social complexity which generally lowers female status.

This exploratory study seeks to explain cassava production and processing in Africa by considering cultural, agronomic, and environmental data. After examining the descriptive results of the agricultural and social contexts of cassava use, the authors build upon Boserup's population density model (1965) to analyze their own hypothesized model of cassava's importance among the sampled societies.

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.

The ability of adults to digest lactose is common only in populations of European and circum-Mediterranean origin, a distribution thought to be a result of genetic adaptation to drinking milk from domestic livestock. Two additional hypotheses have been proposed to explain the distribution of high lactose digestion capacity: (1) supplemental calcium in high-latitude populations prone to vitamin D deficiency and (2) maintenance of water and electrolytes in the body in highly arid environments. However, these hypotheses are confounded by the shared ancestry of populations whose lactose digestion capability has been tested. Therefore, the authors test all three hypotheses using a phylogenetic comparative method for 62 cultures.

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.

The researcher looks for empirical evidence of natural selection as an explanation for worldwide variation in novelty-seeking behavior. Examining the relationship between variability in frequency of the DRD4 exon III 7-repeat allele variant (a variant theorized to stifle dopamine reception and thus encourage compensatory novelty-seeking behavior) and migratory distance from prehistoric humans' origin point in East Africa yields a positive correlation. After controlling for various biogeographic indicators, the researcher theorizes that presence of the DRD4 exon III 7-repeat variant provided an exploratory urge and evolutionary advantage to hunter-gatherers and pastoralists who migrated into unfamiliar environments.