By testing relationships between musical, geographic, genetic, and linguistic distance among nine indigenous groups in Taiwan, the researchers aim to quantitatively evaluate a developing theory of coevolution between these traits. An especially strong correlation between musical variability and genetic distance suggests that music may possess worldwide time depth, diversity, and universality equal to or greater than that of language, and could thus serve as a complementary marker for reconstruction of long-term population shifts.

Genetic, linguistic, and geographic data can be used to explain the distribution of cultural units ("semes") and to understand the evolutionary mechanisms of culture. Three broad models of cultural transmission attempt to explain why cultures share semes: (1) Cultural diffusion, emphasizing horizontal transmission. (2) Local adaptation, where trail-and-error learning leads to the independent adoption of semes by different peoples living in similar environments. (3) Demic diffusion, which emphasizes vertical and frequency-dependent transmission. Authors test the explanatory power of each model using cultural, genetic, linguistic and geographic data from 36 African cultures.

Dopamine receptor D4 (DRD4) exhibits the largest number of polymorphisms of any dopamine receptor yet identified, and variation in DRD4 has been linked to variation in traits such as novelty-seeking and attention deficit/hyperactivity disorder. DRD4 also exhibits large variation between populations. Here, the authors test the hypothesis that natural selection acting on DRD4 may account for variation in between-population migratory patterns, using genetic and historical data from 39 populations.

The myths, legends, and folktales of nearby groups tend to more alike than those of more distant groups. Three competing models attempt to explain this distribution of cultural traits: (1) vertical transmission, (2) horizontal transmission, and (3) independent innovation. The authors examine 18 Arctic hunter-gatherer groups to quantify the extent to which geographic distance, cultural ancestry, and effective population size predict overlap in folktale inventories.

The 'obstetrical dilemma' postulates that human females evolved a pelvis shape that was a compromise between the needs of bipedal locomotion and the need for a wider pelvic opening. The implication is that the female pelvis should be similar across the world. Researchers examine the size and shape of the birth canal of female individuals in the Goldman and Human Origin datasets. Contrary to the 'obstetrical dilemma,' the findings reveal that there is indeed significant geographical variation in size and shape of the female birth canal. Neutral evolutionary processes, particularly genetic drift, were suggested to be influential in female canal shape whereas the predicted effects of climate on canal diversity were only minimal.

This study retests the work by Ember, Ember and Low (2007) on male mortality and pathogen stress as predictors of nonsororal polygyny. The authors argue that the work of Ember, Ember, and Low is biased because it does not include a variable for cultural trait transmission. Restesting the original Ember, Ember and Low data, including a variable for cultural trait transmission, authors find that male mortality and pathogen stress loose their significance and cultural trait transmission is the only significant predictor of nonsororal polygyny.

Inter-group variation is greater in humans than in any other animal, and scholars continue to debate the cause of this diversity. Two competing explanatory models of human variation emphasize either (1) ecological differences and "evoked" culture or (2) population-level effects of cultural transmission. The former emphasizes mechanisms that operate within a single generation, while the latter emphasizes cumulative cultural history operating over many generations. To test these competing models, the authors measured the relative power of ecological variables as compared to culture history to predict behavioral variation in 172 western North American tribes. Culture history is subdivided into culture phylogeny (based on language phylogeny) and spatial distance.

This article explores the possible relationship between the cultural evolution of language, music, and genetic variation beyond the level of language families. Due to their linguistic diversity, the authors use a sample of 14 Northeast Asian societies with matching information on their music, genetics, and linguistic patterns. The variables measuring language are lexicon, phonology, and grammar. Then, the authors compare each variable's relationship to music and genetic variation. The results only show a significant correlation between grammar and genetic variation.

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 author investigates whether geographic factors--namely high elevation or 1500 m+ above sea level (reduced atmospheric pressure)-- impact the production, use, and ubiquity of ejective phonemes in eight non-contiguous language clusters. It is suggested that increased use of ejective phonemes has a physiological benefit: the reduction of water vapor loss via exhaled air. Evidence is presented in support of the hypothesized geographic-phonetic linkage.