Visual Contact Enhances Multimodal Alignment in Choral Singing

Singing in a choir requires integration of auditory and visual inputs. Visual contact plays a crucial role in coordinating music and movement and enhancing synchrony among singers. In this study, we investigated the effects of visual contact and activity type on kinematic and acoustic descriptors in choir singing. We studied four SATB (Soprano, Alto, Tenor, Bass) quartets performing different activities (chat, monophony, polyphony, improvisation) in two conditions, facing each other or back-facing. Data were collected using studio cameras and accelerometers. We found significant interactions between visual contact, activity type, and trial on various behavioral markers. Visual contact between singers increased head and hand movements across all activities. Hand synchrony was significantly higher during musical activities vs chat. Also, structured musical activities (monophony and polyphony) increased head synchrony, tone onset energy, and tone onset synchrony compared to free-form activities (chat and improvisation). These findings highlight the importance of visual cues in maintaining synchrony and coordination during choir singing and provide a multimodal understanding of the differences between joint spoken and sung performances.