When the Music’s No Good: Rhythms Prompt Interactional Synchrony But Impair Affective Communication Outcomes

Spontaneous motion synchrony between interaction partners benefits the interaction. Here we probed how musical rhythms, which are highly temporally organized, modulate this process. We video-taped conversations held in silence or with an auditory background that was metrical and regular (one measure looped), metrical and irregular (different measures in random order), non-metrical and regular, or non-metrical and irregular. Motion time-series derived from the videos entered a cross-wavelet coherence analysis showing that more musical rhythms amplified rhythm-relevant motion frequencies at the level of the individual and facilitated social synchronizing at the level of the dyad. Yet, we also observed rhythm-specific motion interference effects and reduced conversation pleasantness when compared with silence. These results indicate that musical rhythms, perhaps by imposing a temporally rigid mode of synchronizing, hinder rather than further ongoing social processes. Silence or sounds with little temporal organization and predictability seem preferable as a backdrop for interactional exchange.