Multimodal perception of interpersonal synchrony : evidence from global and continuous ratings of improvised musical duo performances

Investigating cues that underpin perceptual judgments of interpersonal coordination has important implications for understanding sociocognitive evaluations of the quality of human interactions. With a focus on musical interpersonal coordination, we conducted 2 experiments investigating the impact of music style, modality of stimulus presentation, rater expertise, and audio/visual stimulus features on ratings of perceived synchrony in improvised duo performances. In the first experiment, participants made synchrony ratings following 10-s excerpts of musical performances, whereas in the second experiment, participants rated longer (up to 1 min) excerpts continuously as the music unfolded. Several consistent results emerged across the 2 experiments, including that participants perceived standard jazz improvisations featuring a regular beat as significantly more synchronous than free improvisations that aimed to eschew the induction of such a beat. However, ratings of perceived synchrony were more similar across these 2 styles when only the visual information from the performance was available, suggesting that performers' bodily cues functioned similarly to communicate and coordinate musical intentions. Computational analysis of the audio and visual aspects of the performances indicated that synchrony ratings increased with increases in audio event density and when coperformers engaged in periodic movements at similar frequencies, whereas the salience of visual information increased when synchrony ratings were made continuously over longer timescales. These studies reveal new insights about the correspondence between objective and subjective measures of synchrony and contribute methodological advances indicating both parallels and divergences between the results obtained in paradigms utilizing global versus continuous ratings of musical synchrony.