Speaker movement correlates with prosodic indicators of engagement

Recent research on multimodal prosody has begun to identify associations between discrete body movements and categorical acoustic prosodic events such as pitch accents and boundaries. We propose to generalize this work to understand more about continuous prosodic phenomena distributed over a phrase -like those indicative of speaker engagement -and how they covary with bodily movements. We introduce movement amplitude, a new vision-based metric for estimating continuous body movements over time from video by quantifying frameto-frame visual changes. Application of this automatic metric to a collection of video monologues demonstrates that speakers move more during phrases in which their pitch and intensity are higher and more variable. These findings offer further evidence for the relationship between acoustic and visual prosody, and suggest a previously unreported quantitative connection between raw bodily movement and speaker engagement.