Respiratory markers of conversational interaction.

Respiratory movements were recorded from 10 dyads (20 subjects) during quiet breathing, reading aloud, spontaneous monologue, scripted dialog, and spontaneous conversation. Timing measures of inspiratory, expiratory, and total cycle duration were used to compare respiratory function during quiet breathing, listening, and speech. Cross-correlation analyses of the respiratory movements of conversational partners provided an index of conversational synchrony. Inspiratory duration was found to be the most consistent and sensitive measure for discriminating quiet breathing from speech breathing. In the scripted dialog and spontaneous conversation conditions, respiratory kinematics changed during listening to more closely resemble speech, and systematic changes were observed in anticipation of turn-taking speech onset. For the breathing cycles immediately surrounding turn changes and simultaneously produced vocal events, the kinematic signals of conversational partners were strongly correlated. Results are discussed in the context of similar findings concerning conversational interactions and motor preparation for speech.