In this article the researcher conducted five different studies on in-group or "we-group" vs out-group or "they-group" discrimination practices. Two previous hypotheses are re-examined, the pathogen stress hypothesis and the rice-wheat hypothesis, in order to explain heightened ingroup-outgroup differentiation, before turning to overarching geographical hypothesis. Each of the five studies look at a different group of societies cross-culturally, ending in an index of intergroup discrimination by individuals across 222 countries in study 5. All five studies conclude that differentiation between us and them varies based on geographical location and more specifically, along latitude.

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).

This article examines predictors of intimacy between husbands and wives. Emphasis is on equality of spouses. A causal model is presented.

The author investigates the associations between production relations, the character of productive forces, and sexual life. A significant correlation was found between production relations and the character of productive forces. Results also showed that more sexual freedom is associated with higher level of development of productive forces and an absence of internal oppression.

This study examines relationships among descent, marriageable relatives, residence, family, and mode of production.

Based on work by Rosenblatt (1966), this article tests a hypothesis relating sexual freedom to romantic love. Findings suggest a relationship between premarital and extramarital sexual permissiveness equality for women and men and romantic love.

Previous cross-cultural studies of romantic love have, in the authors' view, been plagued by vague definitions of the concept and a conflation of cultural, bio-psychological, and social factors. Thus, the authors distinguish between the social aspect of romantic love (which they argue is a universal human predisposition) and the variable cultural valuation of romance. In a large cross-cultural sample, the authors test the hypotheses that gender equality and family organization are important predictors of the cultural valuation of romantic love.

This paper presents research on the factors that promote romantic love as a basis for marriage in non-industrial societies. After a discussion of the previous literature on romantic love in ethnographic societies, the authors used the SCCS, EA, and data from eHRAF to create a data set of 109 cultures and then utilized multiple ordinal regression to test the relationship between different types of families and post-marital residence practices and the importance of romantic love in marriage. The findings show that monogamy is significantly correlated with romantic love, while nuclear family organization and neolocal post-marital residence are not significantly correlated. The presence of polygyny is found to lower the probability of romantic love being a basis for marriage. These findings contradict previous research, which found a relationship between non-neolocal post-marital residence and the presence of romantic love in marriage.

The researchers develop and compare two evolutionary models to evaluate the association between social stratification and female genital modification(FGMo) in a cross-cultural African sample, theorizing that social hierarchy creates competition for high-value males in which FGMo acts as a costly demonstration of paternity certainty. Although the null model outperforms the stratification model when applied to empirical data, an association between FGMo and stratification is found in the expected direction. The authors suggest that while stratification may be an important factor in the de novo origins of FGMo, spread and persistence of the practice subsequently become more heavily dependent on other selective forces.

The study proposes a Bayesian modeling framework to analyze and examine the mapping between emotions and speech prosody. The models are fitted to a large collection of emotional prosody recordings, and the study reveals that the mapping varies across corpora, individuals, cultures, and sexes. The study suggests that models accounting for mapping differences across these factors outperform models assuming a global mapping.