Ben Schultz: Get into the groove: Stimulating the motor system with salient acoustic features

Date and time: 6 October 2017. 15:30-17:00

Location: B0.208. Science Park 904

Speaker: Benjamin G. Schultz (Basic & Applied Neurodynamics laboratory, Department of Neurosychology & Psychopharmacology, Faculty of Psychology & Neuroscience, Maastricht University, The Netherlands)

Title: Get into the groove: Stimulating the motor system with salient acoustic features

Abstract: When listening to music, humans spontaneously synchronize their movements with different aspects of the sound. We propose that such movements are a direct result of specific acoustic features that activate motor responses in the peripheral nervous system. To test this hypothesis, participants (N = 42) remained still and listened to 12 musical excerpts while electromyography (EMG) was recorded on the hand and arm. Participants then provided continuous salience ratings using a slider to assess how much certain aspects of the sound stood out relative to other sounds with no instruction regarding which acoustic feature(s) to use for their judgments. Acoustic features were extracted from the excerpts, specifically, intensity (perceived as loudness), inharmonicity (pitch dissonance), and timbre (e.g., spectral centroid). Time series analyses were conducted for each participant and excerpt to assess the cross-correlation between EMG activity, salience ratings, and acoustic features. Consistent moderate cross-correlations were evident between EMG activity and intensity, inharmonicity, and spectral centroid. Intensity and spectral centroid demonstrated moderate cross-correlation with salience ratings. Overall, results suggest that intensity and spectral centroid are acoustic features that simultaneously influence motor activity and salience perception. Inharmonicity also elicits a motor response but is not perceived as salient. Results are discussed within a dynamical systems framework that suggests continuous sound streams can shape our movements based on several different rhythmic features that are not necessarily periodic, thus aiding sensorimotor synchronization. Findings have implications for motor and speech rehabilitation techniques that require listening and acting upon auditory stimuli (e.g., rhythmic auditory stimulation).