Published papers

Culture evolves,1–5 but the existence of cross-culturally general regularities of cultural evolution is debated.6–8 As a diverse but universal cultural phenomenon, music provides a novel domain to test for the existence of such regularities.9–12 Folk song melodies can be thought of as culturally transmitted sequences of notes that change over time under the influence of cognitive and acoustic/physical constraints.9–15 Modeling melodies as evolving sequences constructed from an “alphabet” of 12 scale degrees16 allows us to quantitatively test for the presence of cross-cultural regularities using a sample of 10,062 melodies from musically divergent Japanese and English (British/American) folk song traditions.17,18 Our analysis identifies 328 pairs of highly related melodies, finding that note changes are more likely when they have smaller impacts on a song's melody. Specifically, (1) notes with stronger rhythmic functions are less likely to change, and (2) note substitutions are most likely between neighboring notes. We also find that note insertions/deletions (“indels”) are more common than note substitutions, unlike genetic evolution where the reverse is true. Our results are consistent across English and Japanese samples despite major differences in their scales and tonal systems. These findings demonstrate that even a creative art form such as music is subject to evolutionary constraints analogous to those governing the evolution of genes, languages, and other domains of culture.

We compare and contrast the 60 commentaries by 109 authors on the pair of target articles by Mehr et al. and ourselves. The commentators largely reject Mehr et al.'s fundamental definition of music and their attempts to refute (1) our social bonding hypothesis, (2) byproduct hypotheses, and (3) sexual selection hypotheses for the evolution of musicality. Instead, the commentators generally support our more inclusive proposal that social bonding and credible signaling mechanisms complement one another in explaining cooperation within and competition between groups in a coevolutionary framework (albeit with some confusion regarding terminologies such as byproduct and exaptation). We discuss the proposed criticisms and extensions, with a focus on moving beyond adaptation/byproduct dichotomies and toward testing of cross-species, cross-cultural, and other empirical predictions.

© 2019, The Author(s). The concept of cultural evolution was fundamental to the foundation of academic musicology and the subfield of comparative musicology, but largely disappeared from discussion after World War II despite a recent resurgence of interest in cultural evolution in other fields. I draw on recent advances in the scientific understanding of cultural evolution to clarify persistent misconceptions about the roles of genes and progress in musical evolution, and review literature relevant to musical evolution ranging from macroevolution of global song-style to microevolution of tune families. I also address criticisms regarding issues of musical agency, meaning, and reductionism, and highlight potential applications including music education and copyright. While cultural evolution will never explain all aspects of music, it offers a useful theoretical framework for understanding diversity and change in the world’s music.

Alan Lomax’s Cantometrics Project was arguably both the most ambitious and the most controversial undertaking in music and science that the world has known. Its flagship component, Lomax’s “cantometric” analysis of approximately 1,800 songs from 148 worldwide populations using 36 classificatory features, sparked extensive debate. While Lomax responded to some criticisms, neither his final conclusions nor the evidence on which they were based were ever fully made clear. For decades, neither cantometrics nor Lomax’s related projects involving dance, speech, popular music, digital humanities, pedagogy, and activism were widely adopted by other researchers, but there has been a resurgence of interest since Lomax’s death in 2002. Here, I provide a comprehensive critical review of the Cantometrics Project, focusing on issues regarding the song sample, classification scheme, statistical analyses, interpretation, and ethnocentrism/reductionism. I identify misunderstandings, improvements that were made, and criticisms that remain to be addressed, and distil Lomax’s sometimes-conflicting claims into diagrams summarizing his three primary results: (1) ten regional song-style types, (2) nine musical factors representing intra-musical correlations, and (3) correlations between these musical factors and five factors of social structure. Although Lomax’s interpretations regarding correlations between song style and social structure appear weakly supported, his historical interpretations regarding connections ranging from colonial diaspora to ancient migrations provide a more promising starting point for both research and teaching about the global arts. While Lomax’s attempts to correlate features of social structure such as gender, religion, politics, and economics with stylistic features of musical performance largely failed to gain acceptance, the Cantometrics Project can still provide both inspiration and cautionary lessons for future exploration of relationships between music and culture.

© 2018, © American Sociological Association 2018. Proponents of the Axial Age contend that parallel cultural developments between 800 and 200 BCE in what is today China, Greece, India, Iran, and Israel-Palestine constitute the global historical turning point toward modernity. The Axial Age concept is well-known and influential, but deficiencies in the historical evidence and sociological analysis available have thwarted efforts to evaluate the concept’s major global contentions. As a result, the Axial Age concept remains controversial. Seshat: Global History Databank provides new tools for examining this topic in social formations across Afro-Eurasia during the first two millennia BCE and first millennium CE, allowing scholars to empirically evaluate the varied and contrasting claims researchers have put forward. Results undercut the notion of a specific “age” of axiality limited to a specific geo-temporal localization. Critical traits offered as evidence of an axial transformation by proponents of the Axial Age concept appeared across Afro-Eurasia hundreds, and in some cases thousands, of years prior to the proposed Axial Age. Our analysis raises important questions for future evaluations of this period and points the way toward empirically-led, historical-sociological investigations of the ideological and institutional foundations of complex societies.

Why do humans make music? Theories of the evolution of musicality have focused mainly on the value of music for specific adaptive contexts such as mate selection, parental care, coalition signaling, and group cohesion. Synthesizing and extending previous proposals, we argue that social bonding is an overarching function that unifies all of these theories, and that musicality enabled social bonding at larger scales than grooming and other bonding mechanisms available in ancestral primate societies. We combine cross-disciplinary evidence from archaeology, anthropology, biology, musicology, psychology, and neuroscience into a unified framework that accounts for the biological and cultural evolution of music. We argue that the evolution of musicality involves gene-culture coevolution, through which proto-musical behaviors that initially arose and spread as cultural inventions had feedback effects on biological evolution due to their impact on social bonding. We emphasize the deep links between production, perception, prediction, and social reward arising from repetition, synchronization, and harmonization of rhythms and pitches, and summarize empirical evidence for these links at the levels of brain networks, physiological mechanisms, and behaviors across cultures and across species. Finally, we address potential criticisms and make testable predictions for future research, including neurobiological bases of musicality and relationships between human music, language, animal song, and other domains. The music and social bonding (MSB) hypothesis provides the most comprehensive theory to date of the biological and cultural evolution of music.

Culture evolves in ways that are analogous to, but distinct from, genomes. Previous studies examined similarities between cultural variation and genetic variation (population history) at small scales within language families, but few studies have empirically investigated these parallels across language families using diverse cultural data. We report an analysis comparing culture and genomes from in and around northeast Asia spanning 11 language families. We extract and summarize the variation in language (grammar, phonology, lexicon), music (song structure, performance style), and genomes (genome-wide SNPs) and test for correlations. We find that grammatical structure correlates with population history (genetic history). Recent contact and shared descent fail to explain the signal, suggesting relationships that arose before the formation of current families. Our results suggest that grammar might be a cultural indicator of population history while also demonstrating differences among cultural and genetic relationships that highlight the complex nature of human history.

Phylogenetic trees or networks representing cultural evolution are typically built using methods from biology that use similarities and differences in cultural traits to infer the historical relationships between the populations that produced them. While these methods have yielded important insights, researchers continue to debate the extent to which cultural phylogenies are tree-like or reticulated due to high levels of horizontal transmission. In this study, we propose a novel method for phylogenetic reconstruction using dynamic community detection that focuses not on the cultural traits themselves (e.g., musical features), but the people creating them (musicians). We used data from 1,498,483 collaborative relationships between electronic music artists to construct a cultural phylogeny based on observed population structure. The results suggest that, although vertical transmission appears to be dominant, the potential for horizontal transmission (indexed by between-population linkage) is relatively high and populations never become fully isolated from one another. In addition, we found evidence that electronic music diversity has increased between 1975 and 1999. The method used in this study is available as a new R package called DynCommPhylo. Future studies should apply this method to other cultural systems such as academic publishing and film, as well as biological systems where high resolution reproductive data is available, and develop formal inferential models to assess how levels of reticulation in evolution vary across domains.