This study utilizes Bayesian statistics to test the associations between harsh environments (specifically those with higher degrees of climate variability and relatively lower average temperature and precipitation) and alloparental care in societies throughout the world. Results support the hypothesis that societies in harsher environments show higher rates of alloparental care and that societies with higher rates of starvation and resource stress exhibit lower rates of alloparental care. The authors explain this theorizing that in the former relative costs are sufficiently outweighed by the benefits of this type of cooperation and in the latter they are not. They conclude that their results support the plasticity of human alloparenting as a response to varying ecology.

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.

This study follows the theoretical construct of general cultural tightness and looseness (TL). Tightness is thought to be adaptive when facing socioecological threat, such as resource stress, since it involves a greater amount of cooperation. The study asks: "Why do some societies have relatively standardized or uniform clothing and adornment, whereas others have considerable variability across individuals?", which is connected to the broader question of why some societies show more within-group variation. The authors use a sample of 80 non-industrial societies from SCSS, to explore the relationship between general cultural tightness and standardization or synchrony in dress. The results support that tighter societies have more uniformity in dress and that resource stress is a predictor of synchrony. However, it is not supported that egalitarian societies have more synchrony, and that tightness is positively predicted by resource stress.

This study follows the theoretical construct of general cultural tightness and looseness (TL). Tightness is thought to be adaptive when facing socioecological threat, such as resource stress, since it involves a greater amount of cooperation. The study asks: "Why do some societies have relatively standardized or uniform clothing and adornment, whereas others have considerable variability across individuals?", which is connected to the broader question of why some societies show more within-group variation. The authors use a sample of 80 non-industrial societies from SCSS, to explore the relationship between general cultural tightness and standardization or synchrony in dress. The results support that tighter societies have more uniformity in dress and that resource stress is a predictor of synchrony. However, it is not supported that egalitarian societies have more synchrony, and that tightness is positively predicted by resource stress.

This study follows the theoretical construct of general cultural tightness and looseness (TL). Tightness is thought to be adaptive when facing socioecological threat, such as resource stress, since it involves a greater amount of cooperation. The study asks: "Why do some societies have relatively standardized or uniform clothing and adornment, whereas others have considerable variability across individuals?", which is connected to the broader question of why some societies show more within-group variation. The authors use a sample of 80 non-industrial societies from SCSS, to explore the relationship between general cultural tightness and standardization or synchrony in dress. The results support that tighter societies have more uniformity in dress and that resource stress is a predictor of synchrony. However, it is not supported that egalitarian societies have more synchrony, and that tightness is positively predicted by resource stress.

The present research inquires into the effects, if any, that male status and power have on extramarital sex, parental investment, and polygyny. Using sexual selection theory, the hypothesis is that males in higher positions of power and status are more likely to engage in extramarital sexual activities and be in polygynous relationships was supported. There was no support for an association between male extramarital sex and parental investment.

Using t-test, generalized linear models (GLMs) and Bayesian regression models in a sample of 1188 pre-industrial societies, this study explores the research question: Why have foraging, horticulture, and pastoralism persisted into the 20th and 21st century? The authors test the marginal hypothesis and the oasis hypothesis of agricultural intensification. The first hypothesis suggests that foragers persisted because foragers predominantly inhabited marginal habitats that were typically unsuitable for agricultural purposes. The second hypothesis suggests that intensive agriculture emerged in regions characterized by limited biodiversity and a dependable water supply not reliant on local rainfall. In addition, the authors test whether specific kinds of biodiversity (elephants, malaria, and tsetse flies) correlate with agricultural intensification in African societies. The results support the marginal and oasis hypotheses, but only marginally support the African hypothesis, since only tsetse fly has a significant negative correlation to agricultural intensification.

Using t-test, generalized linear models (GLMs) and Bayesian regression models in a sample of 1188 pre-industrial societies, this study explores the research question: Why have foraging, horticulture, and pastoralism persisted into the 20th and 21st century? The authors test the marginal hypothesis and the oasis hypothesis of agricultural intensification. The first hypothesis suggests that foragers persisted because foragers predominantly inhabited marginal habitats that were typically unsuitable for agricultural purposes. The second hypothesis suggests that intensive agriculture emerged in regions characterized by limited biodiversity and a dependable water supply not reliant on local rainfall. In addition, the authors test whether specific kinds of biodiversity (elephants, malaria, and tsetse flies) correlate with agricultural intensification in African societies. The results support the marginal and oasis hypotheses, but only marginally support the African hypothesis, since only tsetse fly has a significant negative correlation to agricultural intensification.

The present study examines 70 Austronesian cultures to test whether political hierarchy, population size, and social inequality have been influential in the conversion of populations to Christianity. Cultural isolation and year of missionary arrival are control variables. Using phylogenetic generalized least squares (PGLS), the researchers test the effect of the three predictor variables on conversion to Christianity and also conduct a multivariate analysis with all variables. The results do not offer support for what is expected by top-down and bottom-up theories of conversion but instead for the general dynamics of cultural transmission.

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.