Embodied groove-synchrony model: movement context reshapes groove-synchrony coupling and its dominant timescale.

Introduction: Groove-the pleasurable urge to move to music-is commonly theorized to arise from embodied engagement with rhythmic structure, particularly through entrained bodily movement. However, it remains unclear how different movement contexts shape the relationship between groove experience and auditory-motor synchronization, and whether stronger synchronization uniformly enhances groove. The present study aimed to clarify how musical syncopation, bodily movement context, and timing-specific synchronization jointly organize the experience of groove. Methods: Participants listened to musical rhythms with three levels of syncopation (low, medium, high) under three movement conditions: Free (movement neither instructed nor restricted), Static (movement restricted), and Dynamic (intentional rhythmic movement required). After each stimulus, participants rated urge-to-move and pleasure. Auditory-motor synchronization was quantified using phase-locking values (PLV) between musical rhythms and head movement at two distinct metrical levels (1 Hz and 2 Hz). To characterize the functional organization of groove across movement contexts, analyses focused on structural equation modeling, complemented by supplementary linear mixed-effects models to assess trial-by-trial associations. Results: Across all movement conditions, urge-to-move robustly increased synchronization at 2 Hz, indicating that motivational drive toward movement facilitates temporal alignment with musical rhythms even when overt movement is constrained. Critically, however, synchronization was not uniformly beneficial for groove. In Free and Dynamic conditions, increased PLV exerted negative effects on groove-related ratings, suggesting that overly rigid temporal alignment may constrain the subjective groove experience. Moreover, the functional role of synchronization differed across movement contexts: groove-related effects were primarily associated with synchronization at a slower metrical level (1 Hz) in the Free condition, whereas beat-level (2 Hz) synchronization played a dominant role in the Dynamic condition, indicating context-dependent temporal scaling of auditory-motor coupling. Discussion: These findings indicate that groove is not simply amplified by stronger synchronization. Instead, groove emerges from a context-dependent balance between entrained bodily engagement with music and the degree to which movement becomes temporally stabilized to rhythmic structure. We propose an Embodied Groove-Synchrony Model, which distinguishes entrained bodily engagement from phase-based synchronization and shows that excessive temporal stabilization can, depending on movement context, attenuate rather than enhance the groove experience.