When did that happen? The dynamic unfolding of perceived musical narrative

People readily imagine narratives in response to instrumental music. Although previous work has established that these narratives show broad intersubjectivity, it remains unclear whether these imagined stories are atemporal, or unfold systematically over the temporal extent of a musical excerpt. To investigate the dynamics of perceived musical narrative, we had participants first listen to 16 instrumental musical excerpts, which had previously been normed for factors of interest. While listening, participants continuously moved a slider to indicate their fluctuating perceptions of tension and relaxation. In a separate experimental session, participants reported the stories they imagined while listening to each excerpt, and then, while listening to the excerpts a final time, clicked a mouse to mark the time points at which they imagined new events in the ongoing imagined story. The time points of these event markings were not uniformly distributed throughout the excerpts, but were clustered at distinct moments, indicating that imagined narratives unfold in real time and entail general consensus about when listeners imagine events in the music. Moreover, the time points at which people tended to imagine events were correlated with the time points at which people tended to perceive salient changes in musical tension, as separately recorded within the first experimental session. The degree of alignment was greater for excerpts high in narrativity than those low in narrativity. Together, these results show that music can dynamically guide a listener's imagination and there is remarkable intersubjectivity in 'when' hear imagined story events in a piece of music.