Speech rates converge in scripted turn-taking conversations

When speakers engage in conversation, acoustic features of their utterances sometimes converge. We examined how the speech rate of participants changed when a confederate spoke at fast or slow rates during readings of scripted dialogues. A beat-tracking algorithm extracted the periodic relations between stressed syllables (beats) from acoustic recordings. The mean interbeat interval (IBI) between successive stressed syllables was compared across speech rates. Participants' IBIs were smaller in the fast condition than in the slowcondition; the difference between participants' and the confederate's IBIs decreased across utterances. Cross-correlational analyses demonstrated mutual influences between speakers, with greater impact of the confederate on participants' beat rates than vice versa. Beat rates converged in scripted conversations, suggesting speakers mutually entrain to one another's beat.