Inter-Subject EEG Correlation Reflects Time-Varying Engagement with Natural Music

Musical engagement can be conceptualized through various activities, modes of listening, and listener states--among these a state of focused engagement. Recent research has reported that this state can be indexed by the inter-subject correlation (ISC) of EEG responses to a shared naturalistic stimulus. While statistically significant ISC has been reported during music listening, these reports have considered only correlations computed across entire excerpts and do not provide insights into time-varying engagement. Here we present the first EEG-ISC investigation of time-varying engagement within a musical work. From a sample of 23 adult musicians who listened to a cello concerto movement, we find varying levels of ISC throughout the excerpt. In particular, significant ISC is observed during periods of musical tension that build to climactic highpoints, but not at the highpoints themselves. In addition, we find that a control stimulus retaining low-frequency envelope characteristics of the intact music, but little other temporal structure, also elicits significant neural correlation, though to a lesser extent than the original. In all, our findings shed light on temporal dynamics of listener engagement during music listening, establish connections between salient musical events and EEG-ISC, and clarify specific listener states that are indexed by this measure.