Music can be seen as a hierarchical structure, constituted of phrases built on smaller units (notes and beats). Empirical evidence shows that listeners are sensitive to notes and beats and can track phrases of regular length when listening to music (Teng, Larrouy-Maestri, & Poeppel, preprint, 2021). However, natural music is not always regular. Here, our study aims at generalizing previous findings to musical stimuli composed of phrases of different lengths.

Thirty-five participants were asked to passively listen to stimuli while their brain activity was recorded with EEG; to complete a behavioural task during which they had to press a button when noticing an onset or offset of music phrases; and to complete questionnaires about musicality and music preferences. The experimental stimuli were created based on themes extracted from J.S. Bach fugues, with length varying from 3 to over 20 beats per phrase. In the regular condition, we used phrases of 4 and 8 beats; in the irregular condition, melodies were constituted of phrases of various length. A control condition was created by shuffling the generated melodies to deconstruct the phrase structure while preserving the acoustic quality.

Preliminary analysis of the behavioural data revealed higher agreement for the regular/irregular conditions compared to the shuffled one. Interestingly, listeners can track phrases regardless of regularity. The current analysis of the EEG data will shed light on the effects observed and help to clarify the cognitive processes underlying the perception of regular and irregular musical phrases.