Conceptual Boundaries of Music: A Behavioral Study of Cross-Cultural Sound Classification

Music is a cultural universal, yet the conceptual boundary between “music” and “non‑music” remains theoretically unsettled. This study used behavioral measures to examine the perceptual judgments of listeners from Brazil, China, and the United States as they classified short sound excerpts and rated their perceived musicality. Participants (N = 103) completed an online survey featuring 24 two‑second stimuli drawn from 11 sound categories, including traditional music from 130 societies and non‑musical sounds from established auditory taxonomies. Descriptively, the mean proportion of “music” classifications was 0.51, with substantial category‑level variation: traditional vocal and non‑vocal music received the highest endorsement rates, whereas speech and environmental sounds received the lowest. Musicality ratings showed a parallel pattern. Inter‑participant agreement, quantified using Krippendorff’s α, was moderate at the aggregate level (α = .73) but generally low within categories.To complement these descriptive patterns, mixed‑effects models were used to assess whether sound category or country predicted responses while accounting for participant‑ and stimulus‑level variability. Both models revealed large, reliable effects of sound category: the two traditional music categories were far more likely to be judged as music and received substantially higher musicality ratings than all other categories. No other category differed significantly from the reference, and country effects were small or nonsignificant. Together, the descriptive and inferential results indicate that listeners share strong intuitions about prototypical musical sounds, but judgments become highly heterogeneous for ambiguous cases, suggesting that the concept of music may be graded and context‑dependent rather than sharply bounded.