Preceding and trailing role-taking in dyad synchronization using finger tapping.

In ensembles, people synchronize the timings of their movements with those of others. Players sometimes take on preceding and trailing roles, whereby one's beat is either slightly earlier or slightly later than that of another. In this study, we aimed to clarify whether the division of preceding and trailing roles occurs in simple rhythmic coordination among non-musicians. Additionally, we investigated the temporal dependencies between these roles. We conducted a synchronous-continuous tapping task involving pairs of people, whereby pairs of participants first tapped to synchronize with a metronome. After the metronome stopped, the participants synchronized their taps to their partners' tap timings, which were presented as auditory stimuli. Except in one trial, the pairs involved participants taking on preceding and trailing roles. Compared to the participants taking on the trailing role, those taking on the preceding role demonstrated enhanced phase-correction responses, while those taking on the trailing role significantly adapted their tempos to match those of their partners. As a result, people spontaneously divided into preceding and trailing roles. The preceding participants tended to reduce asynchronies, while the trailing participants tended to match their tempo to their partners'.