Presenter Name:Emily Wood

School/Affiliation:McMaster University

Co-Authors:Dobromir Dotov, Andrew Chang, Dan Bosnyak, Lucas Klein, Laurel Trainor

Abstract:

Ensemble musicians must anticipate their partners’ actions in order to plan their next notes and to play together. Moreover, musicians play without speaking, so they must rely on nonverbal communication to help them coordinate. One way musicians can communicate is through the subtle sensorimotor signals embedded in their body sway movements. Indeed, musicians’ body sway reveals their intent regarding phrasing, tempo, and dynamics, which help their partners anticipate how to play next.

Our lab has used Granger Causality to measure bidirectional influence, or information flow, between the body sway of musicians in small ensembles. We found that information flow was greater from assigned leaders to assigned followers than vice versa, and was greater when musicians played with emotional expression than without. Here, we show that information flow decreases over time in a string quartet that learns to play an unfamiliar piece together.

A professional string quartet played two unfamiliar pieces of music together eight times in succession. The quartet alternated between playing the unfamiliar pieces in expressive and mechanical conditions. Information flow within the group decreased linearly across trials for both pieces, suggesting that the musicians relied on body sway to help them play together when the pieces were most novel (trial 1), but this reliance decreased as they gained familiarity with playing the pieces together. There was no effect of expressive vs. mechanical playing condition. Overall, our studies show that body sway reflects nonverbal communication in musical ensembles.