In Time Together: The Role of Music-Induced Interpersonal Synchrony on Prosociality

Music is a universal human activity that has long been theorized to promote social bonding and cooperation through interpersonal synchrony. However, in music, several types of synchrony can occur. This thesis investigates whether musical synchrony enhances prosociality more effectively than rhythmic or visual alignment alone (silence). N = 108 participants (54 dyads) were randomly assigned to one of three conditions: silence, isotonic (rhythm only), or music (rhythm + melody). Dyads engaged in coordinated movements using the E-music box, a device that transforms rotational motion into auditory output, and their prosociality (inspected through a cooperation task-based paradigm, prosocial orientation and self-reported ratings) was assessed before and after. Cooperation was measured through the use of economic games by examining cooperative and coordinated risk-taking while prosocial orientation was measured via Social Value Orientation (SVO) for behavioral preferences and self-reported attitudinal prosociality ratings to capture emotional perceptions. Interpersonal synchrony was quantified using motor synchronization values, and potential moderators such as leader–follower dynamics observed from the E-music box task, SVO types and levels of motor synchronization were examined. The results showed that different types of synchronization did not affect the overall level of cooperative risk-taking. However, after synchronizing through rhythm alone or through music, participants coordinated their choices more effectively and therefore earned higher payoffs compared to when they synchronized visually without sound. While SVO scores remained stable across conditions, self-reported prosocial attitudes improved in all groups, with greater gains in music and silent condition compared to isotonic condition. Dyads in the music condition achieved significantly higher synchrony than those in silent and marginally higher than those in isotonic, and higher synchrony predicted increased payoffs, risk-taking, and prosocial ratings. Moderation analyses further revealed that followers were more willing to take risks and reported higher prosocial attitudes than leaders but ultimately earned lower payoffs. These findings indicate that although musical synchrony does not directly shift cooperative risk-taking or trait-level prosocial orientations, it enhances coordinated efficiency and strengthens prosocial attitudes by fostering tighter interpersonal alignment. This supports the view that interpersonal synchrony provides a basis for shared intentionality, linking coordination to social cohesion. By showing how music facilitates cooperation through both behavioral outcomes and subjective prosocial experiences, this study contributes to a growing body of evidence that music serves as a fundamental pathway for sustaining human cooperation. Keywords: Interpersonal Synchrony, Music, Coordination, Cooperation, Prosocial Behavior, Social Bonding, Decision-Making