Articulatory coordination of two vocal tracts

In this paper, we quantify the time-varying coordination of articulator motion for two speakers engaged in two face- to-face speaking tasks: repetition of simultaneously produced words (and word-pairs) and conversation. Correlation map analysis is used to compute the time-varying, correlation between pairs of signals for all possible pairings of signal values. The resulting two-dimensional map of correlation values captures the fluctuations that occur naturally in the coordination within and between speakers, regardless of whether the behaviors are intentionally synchronized or merely entrained (as in conversation). This not only provides a more accurate picture of the correlation between signals, but also underlines the importance of treating fluctuations as potentially important components of biological behavior, rather than discounting them simply as noise.