Behavioral dynamics of rhythm and meter perception: the effect of musical expertise in deviance detection

In two behavioral experiments, we explored effects of long-term musical training on the implicit processing of temporal structures (rhythm, non-rhythm and meter), manipulating deviance detection under different conditions. We used a task that did not require an explicit processing of the temporal aspect of stimuli, as this was irrelevant for the task. In Experiment 1, we investigated whether long-term musical training results in a superior processing of auditory rhythm, and thus boosts the detection of auditory deviants inserted within rhythmic compared to non-rhythmic auditory series. In Experiment 2, we focused on the influence of the metrical positions of a rhythmic series, and we compared musicians and non-musicians' responses to deviant sounds inserted on strong versus weak metrical positions. We hypothesized that musicians would show enhanced rhythmic processing as compared to non-musicians. Furthermore, we hypothesized that musicians' expectancy level would differ more across metrical positions compared to non-musicians. In both experiments, musicians were faster and more sensitive than non-musicians. Although both groups were overall faster and showed a higher sensitivity for the detection of deviants in rhythmic compared to non-rhythmic series (Experiment 1), only musicians were faster in the detection of deviants on strong positions compared to weak ones (Experiment 2). While rhythm modulates deviance processing also in non-musicians, specific effects of long-term musical training arise when a refined comparison of hierarchical metrical positions is considered. This suggests that long-term musical training enhances sensitivity to the metrical structure and improves temporal prediction mechanisms, even during implicit processing of meter.