Beat perception in polyrhythms is influenced by spontaneous motor tempo, musicianship, and played musical style

No two people perceive the same music alike. This may apply especially to polyrhythms, which consist of two or more rhythms with indivisible regular pulses, such as three over four (3:4). Either of these pulses can be perceived as the underlying beat. Previously, we showed that people naturally tap along to pulses that can be subdivided into groups of two or four equally spaced units (i.e., binarized pulses). This propensity for binarized pulses is reduced when the opposite pulse admitting ternary subdivisions is pitched lower. However, individual factors may modulate these binary and low-pitch preferences. Therefore, we examined the influence of spontaneous motor tempo (SMT), musicianship, played instrument, and played musical style on beat perception in 2:3 and 3:4 polyrhythms. Participants with slower SMT synchronized their tapping with slower metrical levels of the pulses admitting binary subdivisions, suggesting that the natural pace with which we move through the world is linked to our perception of musical tempo. In addition, classical musicians were more likely to synchronize with lower pitched pulses than pop/rock musicians when the low pitch was in the pulse admitting ternary subdivisions. This suggests that enculturation in specific musical styles shapes how pitch and rhythm influence beat perception.