UC San Diego

Currently little is known about the brain dynamics and expressive movements that support musical engagement. We hypothesize that repetitive expressive gestures play an important role in inviting musical engagement in listeners, and that these movements can reveal the feelings experienced by the listener. Furthermore, we hypothesize that brain dynamics supporting these expressive movements play a key role in musical engagement. We trained expert and non-expert participants to communicate the feeling of music they are hearing using simple rhythmic U-shaped hand /arm "conducting" gestures that animate the 2-D movement of a spot of light on a video display while we use body motion capture and EEG to record their movements and brain activity. Periodically we introduced a "not engaged" condition during which a distractor task impedes the participant's engagement in the engaged listening task. We then asked viewers to rate the recorded 2-D spot animations of the recorded gestures on a musical emotion rating scale to test to what extent the musical affective experience of the "conductors" can be conveyed by these animations to viewers who do not hear the music. The ratings from the conductor and viewer groups were well correlated, verifying that the affective intent of the conductors' gestures are experienced by viewers. Statistically significant differences were found in the motion capture and EEG data between the fully engaged condition and the not-engaged condition. A comparison of the EEG data recorded during the two conditions revealed low alpha- and theta-synchronization in the parietal- temporaloccipital (PTO) junction which was specific to the engaged condition, and time-locked to the participants' expressive movements. The results from the viewer experiment suggest that the feeling intention of the expressive gesture task is communicable through a single point-light display, and that viewers can distinguish engaged performances from not-engaged performances. Our EEG results suggest that brain dynamics supporting engaged music listening, located at the PTO junction, are co- modulated with the expressive, rhythmic movements made by the listener. The fact that we can non-invasively monitor musical engagement gives us a useful and general tool for music perception research, with possible wider applications to music classification, technology, and therapy