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.

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.

This article uses alliance theory and kin selection theory to examine the relationship between consanguineous marriage and descent system. The author argues that there is no relationship between the severity of incest taboos and the rules of exogamy or endogamy. A series of testable hypotheses regarding incest, marital, and descent rules are presented.

This study focuses on cultural preferences for skin pigmentation. Findings indicate a general preference for lighter pigmentation in women. Cultural and biological theories are offered, and the authors suggest the skin-pigmentation preference is an instance of gene-culture coevolution. Areas for further research to explain the relationship of this finding with other features of society are suggested.

Controlling on a wide range of factors, this article examines the relationship between precolonial systems of leadership succession and contemporary deforestation rates. In a study of areas within the boundaries of 649 precolonial societies, the article finds that areas where local leaders were appointed by social standing were more likely to have poorer institutions governing forest management. The authors emphasize the importance of local governance over forest management and argue that precolonial institutions of leadership still have a bearing on current systems of forest management.

This research examines how national culture influences the speed of COVID-19 spread in different countries. Three studies were conducted, and five national cultural dimensions were found to be significantly related to the speed of COVID-19 spread in the initial stages of the pandemic. These dimensions are power distance, uncertainty avoidance, humane orientation, in-group collectivism, and cultural tightness. The research found that COVID-19 spreads faster in countries with small power distance and strong uncertainty avoidance, low humane orientation and high in-group collectivism, and slower in countries with high cultural tightness.

This study explores predictors of variation in two dimensions of marital residence patterns among hunter-gatherers: 1) the tendency toward patrilocality versus matrilocality and 2) the tendency toward unilocality versus bilocality.

This article examines the relationship between the tightness-looseness of a culture and the variation of COVID-19 cases and deaths through October 2020. With COVID-19 data retrieved from Our World in Data from 57 countries with tightness-looseness figures, the article found the cultures with high levels of tightness had fewer COVID-19 cases and deaths when compared to countries with high levels of looseness. Results suggest support of the evolutionary game theoretic model proposing that people in tight cultures may cooperate with more urgency when under collective threat than people in loose cultures.

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.

The present research investigates food sharing and labor sharing practices of 98 nonindustrial societies. The aims are to: 1) document the frequency and scope of sharing, and 2) test the theory that greater sharing is adaptive in societies subject to more resource stress (including natural hazards).