Intonation and timing in singing early music is unrelated to respiration synchronization

Musical ensemble performance offers a unique context for investigating complex interpersonal coordination. Hyperscanning research revealed the synchronization of physiological processes during coordinated musical interaction. In a previous study, we showed that physical touch enhanced respiratory coupling between professional singers performing together. We expand on this research by investigating whether this respiration coupling affects performance quality in terms of timing and intonation. Eight singers (two for each voice part) performed Renaissance works multiple times, both with and without physical touch. We annotated the recorded vocal tracks with precise onset times and pitch information, resulting in 64,214 tone events. We analyzed timing as mean onset deviation and intonation as mean absolute pitch deviation, both within voice groups. In contrast to the findings on respiration coupling, physical contact had no effect on timing and intonation, indicating that there is no relation between respiration coupling and singing quality. When tested directly with linear mixed effect models, respiration coupling did not predict intonation or timing in five of six models. One model showed a negative effect: higher respiration coupling decreased intonation accuracy. We conclude, in a professionally trained vocal ensemble, increased respiration coupling does not enhance singing quality.