Résumé
Long-term exposure to a social environment leads to the perceptual learning of its regularities. For example, we perceive and produce more proficiently familiar than unfamiliar musical rhythms independently of their complexity (Jacoby et al., 2024). This phenomenon, called rhythmic enculturation, has been largely documented on irregular rhythms but scarcely with regular rhythms.While isochrony (regular rhythm) is pervasive throughout musical cultures (Savage et al., 2015), non-isochronous rhythms are less common and often found in understudied non-Western populations (Henrich et al.,2010). For example, Indian classical music employs non-isochronous beat grouping and the rhythmic structure evolves throughout a musical performance (Clayton, 2000; Clayton et al., 2019).We recruited Indian and French participants in a series of synchronization experiments.French were enculturated to Western music mainly composed of regular metrical structure while Indians were exposed to a wider variety of musical structures. We postulated that French participants were better tunedto interact with isochronous rhythms than Indian participants, the latter being also able to interact with irregular rhythms (Hannon, 2010). In a first exploratory study, participants synchronized their finger movement with a metronome of increasing rate to document synchronization dynamics. French and Indianparticipants had equally stable synchronization and lost synchronization at the same rate. However, French participants moved ahead of the metronome—a supposedly universal phenomenon known as Negative MeanAsynchrony (NMA, Repp, 2005)—but, surprisingly, Indian participants didn’t demonstrate that tendency. The NMA was associated with the overestimation of the metronome frequency when synchronization was lost forFrench, but not for Indians. We hypothesized that the NMA observed in French was due toan over-estimation of the metronome frequency (Pikovsky et al., 2001; Wohlschläger & Koch, 2000), while Indian participants did not exhibit this bias because of their exposure to changing rhythmic structures. A second study investigated this frequency adaptation mechanisms. We examined the participants’ability to synchronize with rates faster or slower than their spontaneous rates and documented the synchronization dynamics with increasing and decreasing metronome rate.Our work extends previous knowledge by showing the role of rhythmic enculturation on the most basic synchronization mechanisms.