This article asks about the types of friendships people prefer across cultures, focusing on closeness and endurance. The authors hypothesize that people generally favor close and enduring friendships, especially when seeking support and social input, while those with self-serving or mate-seeking goals may prefer casual and convenient ones. Using data from 6,224 participants across 12 countries, they find that most people prefer close and enduring friendships, and that preferences largely align with actual friendships. Results also show small but significant effects of Dark Triad traits—particularly Machiavellianism—on friendship preferences. The conclusion is that friendship preferences are broadly consistent across cultures but shaped by individual goals and personality.

This book discusses the characteristics of adolescence cross-culturally and examines the differences in the adolescent experience for males and females. Several relationships are tested in order to gain an understanding of cross-cultural patterns in adolescence.

This book examines population growth rate and its correlates by testing 274 hypotheses (derived from multiple theories) with an 18-society sample. Forty-one of these hypotheses were significant at the .05 level, leading the author to accept these relationships as reflective of the real world. The 274 hypotheses are grouped into 51 broader hypotheses, and marked by (*) where relationships are significant as designated by the author or by significance p < 0.05.

Reputations are an important aspect of human social interactions and cooperation, but much of the research on reputations has focused on a narrow range of domains such as prosociality and aggressiveness. This study aims to provide an empirical view of reputation domains across different cultures by analyzing ethnographic texts on reputations from 153 cultures. The findings suggest that reputational domains vary across cultures, with reputations for cultural conformity, prosociality, social status, and neural capital being widespread. Reputation domains are more variable for males than females, and certain reputation domains are interrelated. The study highlights the need for future research on the evolution of cooperation and human sociality to consider a wider range of reputation domains and their variability across different social and ecological contexts and genders.

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.

Drawing from previous theories on the cultural variation of depression, this article tested the relationship between 24 sociocultural and ecological factors and the prevalence of depression across 195 countries and territories. The authors first conducted a zero-order association test to find the most contributory factors. Those variables were further tested in a regression model, and controlled for the under-reporting of depression by measuring the number of healthcare workers per capita. The authors found that cultural individualism was the only factor that positively predicted depression prevalence in a multiple regression model.

Using experimental methods, these researchers evaluated the function of pride in ten small-scale societies by testing personal pride’s association with valuation by the surrounding community. Their aim was to see if findings from western(-ized), educated, industrialized, rich, and democratic (WEIRD) societies replicate in non-WEIRD societies. Simple linear regression in each society indicates that the amount of pride one feels for a given action closely matches how highly others in the same community value the action. Authors conclude support for the universality of the pride system.

Authors contend that many of the differences across the 50 states can be attributed to the degree to which social entities are "tight" (have many strongly enforced rules and little tolerance to deviance) or "loose" (have few strongly enforced rules and greater tolerance for deviance). Significant correlations were found between many state characteristics and tightness-looseness.

In this study, the authors analyze relationships between witchcraft accusations and the gender of the accused. They find that men are most often accused of witchcraft in their sample of 54 Bantu or Bantoid societies, and are particularly more likely to be accused of witchcraft by unrelated or blood-related individuals or in disputes over wealth or prestige. On the other hand, women are more likely to be accused of witchcraft in affinal relationships, particularly husbands and co-wives, and in situations related to fertility or relationships. Elderly women were also more likely to be accused of witchcraft than elderly men. The authors also examined outcomes of witchcraft accusations, finding that 81% of cases resulted in a negative outcome for the accused. They suggest that competition underlies accusations of witchcraft.

The study builds on a previous study with the Maasai suggesting that matrilineal descent will close that gap of competitive behavior between men and women. The author conducted a lab experiment consisting of 614 individuals representative of 27 ethnic groups in the Democratic Republic of the Congo. In the experiment, the participants completed a timed matching game. First, they played alone with the goal to complete 5 games within 5 minutes to win money. Next, they competed against an undisclosed opponent to complete the most games and to keep all of the winnings. Finally, the participants were able to choose which pay they preferred based solely on the results from the first round. This was designed to reflect competition preference and results indicated that women were less likely to engage in competition regardless of kinship system.