Abstract
Dancing together to music is a common social activity in which movement coordination emerges from the interplay of interpersonal relationships and a shared musical environment. While previous work on dyadic dance movement has focused on individual differences, third-party judgments of synchrony, and disentangling partner- from music- driven coordination, relational and situational determinants of coordination have received less attention. This motion capture study investigated how social affiliation and agency over the music influence movement characteristics and social coordination in young people. A total of 164 adolescents danced in dyads with both a friend and a stranger, and to self- and researcher-selected music in a counterbalanced design. Extracted kinematic features included head and hand movement magnitude, movement complexity, fluidity, interpersonal distance, mutual orientation, and synchrony. Results showed greater, more complex and less fluid movements when participants danced with friends compared to strangers. Head and hand movement magnitudes were larger for self-selected than researcher-selected music, but only when self-selected music followed researcher-selected music. Friends also exhibited higher interpersonal synchrony, danced closer, and looked more towards each other than strangers. These findings shed light on how social and contextual factors shape dance behaviour in adolescence.