Researchers used various hypotheses to determine if cross-country differences in trust and cooperation would predict prosocial COVID-19 responses and policies. Using individual surveys from 34,526 participants from 41 countries, there were no significant associations between trust and cooperation and prosocial behavior, motivation, regulation, or stringency of policies. While the researchers did find significant variation among cross-country individuals, these results were unable to predict country-level prosocial responses.

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.

In this paper, the author argues that moral systems evolved as a way to enforce cooperation between people outside of kin groups. Because cooperation within kin groups has apparent adaptive advantages, it is argued that these moral systems will be less important for societies with tight kin groups and conversely more important for those with looser kin groups. In order to test this theory, the author creates an original model that incorporates both ethnographic data and data from contemporary countries. Thus, it is postulated that historical kinship practices will influence contemporary systems. The paper concludes that there is sufficient historical evidence for this theory.

While it is widely accepted that there are a multitude of variables that contribute to a society’s level of democracy, the authors of this study argue that the prevalence of consanguinity is one that is often overlooked. Using a sample of 70 nations, they tested the relationship between consanguinity (defined as marriage and subsequent mating between second cousins or closer relatives) and level of democracy (defined by both the Polity IV scale and the EIU Index) and found a significant negative relationship. Similarly, when controlled for a host of different variables in multiple regression analysis, the significant relationship between consanguinity and level of democracy held true.

This study examines the phenomenon of parallel-cousin marriage in patrilateral societies and it's relationship with Islamization.

This paper tests some of Levi-Strauss's pronouncements on Crow-Omaha kinship systems cross-culturally. The author tests the relationships between Crow-Omaha and Hawaiian kinship systems and cross-cousin marriage. Results suggest that both kinship systems will prohibit cross-cousin marriage.

This article tests hypotheses related to kinship terms, cousin marriage, and descent rules. Omaha, Crow, Eskimo, and Iroquois systems are each significantly associated with different kinship rules. Material from Northern Ghana is also considered.

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.

The authors predict that fitness outcomes will be negatively associated with spousal relatedness among foragers but positively associated among non-foragers, due to the greater social benefits of intensive kinship systems among non-foragers. Support is found for this hypothesis; however, an interaction effect is discovered with inbreeding, which appears to account for the variability in these relationships independent of subsistence activity. The authors qualify this support in order to explain why the incidence of cousin-marriage in non-foraging societies is not higher.

This article uses factor analysis to identify the key variables underlying the many cross-cultural associations reported by Textor (1967). Twelve factors are identified.