This study sampled over 4,012 language varieties, comparing their version of 40 generally universal words, such as body parts, water, the sun, pronouns, and common behaviors or animals. These language variations were tested in their association to "specific humidity," the variable used to represent ambient humidity of a language location. Results suggest negative association between the dryness of climate and the utilization of vowels, consitent with the idea that dry air affects the behavior of the larynx.

Authors investigate the prevalence of male homosexual preference (MHP) cross-culturally. They employ four models to test the link between level of social stratification and the probability of observing male homosexual preference (MHP). Authors believe that this link supports the hypergyny hypothesis, which proposes that increased social stratification allows for some sort of factor that improves functional female fertility, perhaps through marriage to men of higher social classes. This would thereby allow more access to resources and consequently the ability to support a greater number of more reproductively-successful offspring. Authors do not make a causal link, however; rather, social stratification may be associated with a yet-undetermined pleiotropic factor that is somehow positive despite its cost on functional male fertility.