Synchronization to metrical levels in music depends on low-frequency spectral components and tempo

Previous studies have found relationships between music-induced movement and musical characteristics on more general levels, such as tempo or pulse clarity. This study focused on synchronization abilities to music of finely-varying tempi and varying degrees of low frequency spectral change/flux. Excerpts from six classic Motown/R&B songs at three different tempos (105, 115, and 130 BPM) were used as stimuli in this experiment. Each was then time-stretched by a factor of 5% with regards to the original tempo, yielding a total of 12 stimuli that were presented to 30 participants. Participants were asked to move along with the stimuli while being recorded with an optical motion capture system. Synchronization analysis was performed relative to the beat and the bar level of the music and four body parts. Results suggest that participants synchronized different body parts to specific metrical levels; in particular, vertical movements of hip and feet were synchronized to the beat level when the music contained large amounts of low frequency spectral flux and had a slower tempo, while synchronization of head and hands was more tightly coupled to the weak flux stimuli at the bar level. Synchronization was generally more tightly coupled to the slower versions of the same stimuli, while synchronization showed an inverted u-shape effect at the bar level as tempo increased. These results indicate complex relationships between musical characteristics, in particular regarding metrical and temporal structure, and our ability to synchronize and entrain to such musical stimuli.