The authors examine multiple ecological variables as possible predictors of language diversity in North America using path analysis, mechanistic simulation modelling, and geographically weighted regression. They conclude that many of the variables do not predict language diversity, but rather are mediated by population density. The authors also find that the variables' ability to predict is not universal across the continent, but rather more regional.

Researchers investigated further into why and how humans speak so many languages across the globe, and why they are spread out unevenly. Using two different path analyses, a Stationary Path analysis and a GWPath, researchers tested the effect of eight different factors on language diversity. Out of the eight variables (river density, topographic complexity, ecoregion richness, temperature and precipitation constancy, climate change velocity, population density, and carrying capacity with group size limits), population density, carrying capacity with group size limit, and ecoregion richness had the strongest direct effects. Overall, the study revealed the role of multiple different mechanisms in shaping language richness patterns. The GWPath showed that not only does the most important predictor of language diversity vary over space, but predictors can also vary in the direction of their effects in different regions. They conclude that there is no universal predictor of language richness.

This paper examines the enormous variation in linguistic diversity among Pacific Islands by testing its relationship with various environmental variables put forth in several common theories of language richness. The researchers identify variables relating to land area and island isolation as accounting for about half of variation in linguistic diversity, suggesting that the other half is a result of complex social factors.

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.

In this article, the authors seek to investigate why some societies reject agriculture despite its many benefits. By modeling data regarding ecological fitness and cultural transmission, the authors found predictors for the degree to which a society relies on agriculture. The authors conclude that the degree of fitness a local environment had for early domesticates as well as the degree of contact with neighboring societies strongly predicts levels of dependence on agriculture.

Belief in moralizing high gods (MHGs) has been theorized as a response to unfavorable environments, as a way to normalize behavior. In this study, researchers test the theory by creating a model for predicting the distribution of MHGs. They run many alternative models, testing the effects of resource abundance, climate stability, and pertinent social factors on the occurrence of belief in MHGs. Based on the ten most supported models, they create an average model that predicts MHGs within cultures with “excellent” accuracy.

This study uses macroecological approaches to test the impact of climate, social environment, inter-group borrowing and cultural history on vernacular house architecture among 1140 societies. The authors suggest that certain features will be influenced: wall materials, ground plan, roof shape, and floor placement. They use mixed binary and multinominal regressions models to test these predictions. The results strongly support that climatic drivers, cultural continuity, and inter-group borrowing predict three out of the four features: wall materials, roof shape, and floor placement. Social drivers are a strong predictor of every feature tested.

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.

In this article, the authors seek to determine cross-culturally valid predictors of dominant types of human subsistence around the world. They did this by formulating multiple models that incorporate different combinations of environmental, geographic, and social factors. These models were then used to test various hypotheses posed throughout the anthropological literature surrounding factors that determine dominant subsistence strategies.

Authors Michael Burton and Douglas White present and test an ecological model for the process of agricultural intensification that aims to explain variance in (and the reduction in) female contribution to agriculture. The model synthesizes and expands upon findings put forth by previous studies in order to create a more comprehensive design. Results suggest that the strongest predictors of female contribution to agriculture are the number of dry months, the importance of domesticated animals to subsistence, and the use of the plow in farming. Crop type, although a weaker predictor, is also supported.