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.

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.

Researchers used population samples from the ALFRED database and the Human Genome Diversity Project (HGDP), in conjunction with 68 populations from the Ethnographic Atlas, in an attempt to identify specific genes involved in human adaptation to environmental stimuli as a result of migration. Specifically, researchers looked at the allele frequencies for four different genes typically associated with varying subsistence forms. These four included the APOE apolipoprotein E gene (lipid transport and regulation of cholesterol), LCT lactase gene (enzyme that decomposes lactose), CCR5 chemokine receptor gene (deletion mutation that decreases immunodeficiency virus propagation), and the ADH1B alcohol dehydrogenase gene (important enzyme for alcohol metabolism). The allele frequencies were then analyzed to distinguish any possible correlation to economic-culture types using a two-sided Spearman Test. Researchers also ran a similar test to analyze allele frequencies and pathogen load, however the majority of the findings were not statistically significant. The findings suggest that there is a definite relationship between the allele frequencies and type of economy of a population.

The ability of adults to digest lactose is common only in populations of European and circum-Mediterranean origin, a distribution thought to be a result of genetic adaptation to drinking milk from domestic livestock. Two additional hypotheses have been proposed to explain the distribution of high lactose digestion capacity: (1) supplemental calcium in high-latitude populations prone to vitamin D deficiency and (2) maintenance of water and electrolytes in the body in highly arid environments. However, these hypotheses are confounded by the shared ancestry of populations whose lactose digestion capability has been tested. Therefore, the authors test all three hypotheses using a phylogenetic comparative method for 62 cultures.

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.

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 paper examines patterns of cultural learning in pastoralist societies and compares them to those found in hunter-gatherer societies. The study analyzed 198 texts from 13 pastoralist cultures in the eHRAF World Cultures database and found that most cultural skills and knowledge were acquired in early childhood, with parents and non-parental adults as the primary sources of transmission. Teaching was the most common form of learning across all age groups, with minimal variation in transmission between different age groups. While similarities were found between the cultural learning patterns of pastoralists and hunter-gatherers, pastoralists were less likely to mention learning from peers and more likely to mention learning via local enhancement and stimulus enhancement. The importance of teaching did not increase with age in pastoralist societies, unlike in hunter-gatherer societies.

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.

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.

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.