The authors investigate the relationship between linguistic diversity and various environmental and spatial variables associated with biodiversity. Most of these variables predict linguistic diversity variably across different continents, and more so within Africa and extended Asia (Asia, the Pacific, and Australia) than within Europe and the Americas. This divide is theorized to be a result of differences in demography and impact of colonialism between the two global regions. However, two environmental factors, landscape roughness and density of river systems, are found to be significant predictors across all global regions. The authors suggest that, as in processes of speciation, rough terrain and watercourses both create physical barriers between which languages can develop in isolation while, in the case of river junctions, also providing transportation routes whereby hybrid languages can occasionally manifest.

Is grammatical complexity shaped by sociodemographic and sociolinguistic factors? The previously accepted "linguistic niche hypothesis" claims that with an increased number of nonnative speakers in a social group (high exotericity), grammatic complexity decreases; on the other hand, grammatical complexity increases amongst isolated linguistic communities (low exotericity). Through the use of spatiophylogenetic modelling of 1314 languages, the authors of this study do not find adequate evidence to support the linguistic niche hypothesis. Instead, they suggest that linguistic complexity is better predicted by phylogeny and geographic contiguity.

Is grammatical complexity shaped by sociodemographic and sociolinguistic factors? The previously accepted "linguistic niche hypothesis" claims that with an increased number of nonnative speakers in a social group (high exotericity), grammatic complexity decreases; on the other hand, grammatical complexity increases amongst isolated linguistic communities (low exotericity). Through the use of spatiophylogenetic modelling of 1314 languages, the authors of this study do not find adequate evidence to support the linguistic niche hypothesis. Instead, they suggest that linguistic complexity is better predicted by phylogeny and geographic contiguity.

The authors compare language phylogenies and spatial distributions with folktale frequencies of Indo-European peoples in order to reconstruct their cultural transmission. A stronger association is found between folktale frequency and language phylogeny than has been proposed in earlier literature studies, indicating that vertical transmission is more influential on folktale distribution than horizontal transmission through spatial proximity. Finally, the frequencies of certain folktales appear to trace the ancestral divergences of Indo-European languages to a much deeper level than previously though, suggesting that folktales are representative of broader features of culture, rather than recent literary inventions.

Using frequentist and Bayesian multi-level models in a sample of two international samples, the authors test whether there are significant sex differences in moral judgments across a large-scale examination of countries. They compare men and women using the five components of the Moral Foundations Theory: 1) care, (2) fairness, (3) loyalty, (4) authority, and (5) purity. In addition, they study the differences when considering socioeconomic and gender-equality status. The results partially support the presence of significant sex differences. While care, fairness, and purity were consistently higher for women; loyalty and authority were highly variable. The study also shows that there are larger sex differences in moral judgments across more individualist, WEIRD, and gender-equal societies.

The article discusses the role of gender in within-society variation in cooperative behavior, and whether gender differences in cooperation emerge similarly across diverse societies. The authors use cross-cultural datasets of 4- to 15-year-old children's preferences for equality in experimental tasks measuring prosociality and fairness to investigate these questions. They find that gender has little impact on the development of prosociality and fairness within the datasets, and there is not much evidence for substantial societal variation in gender differences. The authors discuss the implications of these findings for understanding the nature and origin of gender differences in cooperation and for future research.

Using HRAF's ethnographic reports from 11 immigrant groups to North America (1959-1989), the author asks: what social structural factors account for these patterns of language loss and retention? While focusing on the second and third generations, this study assesses the impact of residence, religion, school, festivals, homeland, marriage, and labor on language retention. The author suggests that residential closeness and the continued practice of religious rituals from the country of origin are the main factors influencing mother tongue maintenance into the third generation, while participation in community festivals is a marginal predictor.

In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

This article explores the following questions: What environmental and cultural factors might explain variation in prejudice across cultures? Do these factors explain the intention to vote for nationalist politicians? The authors perform seven studies, focusing on the link between cultural tightness and the rise of prejudice in cultures. They theorize that cultural tightness is positively correlated with the rise of prejudice against people perceived as disrupting the social order. From this theory, they suggest three hypotheses: 1) cultural variation in tightness is related to cultural variation in prejudice, 2) cultural tightness is related to the support for nationalist politicians, and 3) cultural tightness is a link between ecological threats and prejudice. The results support these hypotheses, offering a cultural evolutionary perspective on prejudice.

This article explores the following questions: What environmental and cultural factors might explain variation in prejudice across cultures? Do these factors explain the intention to vote for nationalist politicians? The authors perform seven studies, focusing on the link between cultural tightness and the rise of prejudice in cultures. They theorize that cultural tightness is positively correlated with the rise of prejudice against people perceived as disrupting the social order. From this theory, they suggest three hypotheses: 1) cultural variation in tightness is related to cultural variation in prejudice, 2) cultural tightness is related to the support for nationalist politicians, and 3) cultural tightness is a link between ecological threats and prejudice. The results support these hypotheses, offering a cultural evolutionary perspective on prejudice.