December 2016 MIMM Journal Club

Music is present in every culture, but the degree to which it is shaped by biology remains debated. One widely discussed phenomenon is that some combinations of notes are perceived by Westerners as pleasant, or consonant, whereas others are perceived as unpleasant, or dissonant1. The contrast between consonance and dissonance is central to Western music2,3, and its origins have fascinated scholars since the ancient Greeks4–10. Aesthetic responses to consonance are commonly assumed by scientists to have biological roots11–14, and thus to be universally present in humans15,16. Ethnomusicologists17 and composers8, in contrast, have argued that consonance is a creation of Western musical culture6. The issue has remained unresolved, partly because little is known about the extent of cross- cultural variation in consonance preferences18. Here we report experiments with the Tsimane’—a native Amazonian society with minimal exposure to Western culture—and comparison populations in Bolivia and the United States that varied in exposure to Western music. Participants rated the pleasantness of sounds. Despite exhibiting Western-like discrimination abilities and Western-like aesthetic responses to familiar sounds and acoustic roughness, the Tsimane’ rated consonant and dissonant chords and vocal harmonies as equally pleasant. By contrast, Bolivian city- and town-dwellers exhibited significant preferences for consonance, albeit to a lesser degree than US residents. The results indicate that consonance preferences can be absent in cultures sufficiently isolated from Western music, and are thus unlikely to reflect innate biases or exposure to harmonic natural sounds. The observed variation in preferences is presumably determined by exposure to musical harmony, suggesting that culture has a dominant role in shaping aesthetic responses to music.