Even within equitonal isochronous sequences, listeners report perceiving differences among the tones, reflecting some grouping and accenting of the sound events. In a previous study, we explored this phenomenon of �subjective rhythmization� physiologically through brain event-related potentials (ERPs). We found differences in the ERP responses to small intensity deviations introduced in different positions of isochronous sequences, even though all sound events were physically identical. These differences seemed to follow a binary pattern, with larger amplitudes in the response elicited by deviants in odd-numbered than in even-numbered positions. The experiments reported here were designed to test whether the differences observed corresponded to a metrical pattern, by using a similar design in sequences of a binary (long-short) or a ternary (long-short-short) meter. We found a similar pattern of results in the binary condition, but a significantly different pattern in the ternary one. Importantly, the amplitude of the ERP response was largest in positions corresponding to strong beats in all conditions. These results support the notion of a binary default metrical pattern spontaneously imposed by listeners, and a better processing of the first (accented) event in each perceptual group. The differences were mainly observed in a late, attention-dependent component of the ERPs, corresponding to rather high-level processing.

We investigate how the presence of performance microstructure (small variations in timing, intensity, and articulation) influences listeners' perception of musical excerpts, by measuring the way in which listeners synchronize with the excerpts. Musicians and nonmusicians tapped on a drum in synchrony with six musical excerpts, each presented in three versions: mechanical (synthesized from the score, without microstructure), accented (mechanical, with intensity accents), and expressive (performed by a concert pianist, with all types of microstructure). Participants' synchronizations with these excerpts were characterized in terms of three processes described in Mari Riess Jones's Dynamic Attending Theory: attunement (ease of synchronization), use of a referent level (spontaneous synchronization rate), and focal attending (range of synchronization levels). As predicted by beat induction models, synchronization was better with the temporally regular mechanical and accented versions than with the expressive versions. However, synchronization with expressive versions occurred at higher (slower) levels, within a narrower range of synchronization levels, and corresponded more frequently to the theoretically correct metrical hierarchy. We conclude that performance microstructure transmits a particular metrical interpretation to the listener and enables the perceptual organization of events over longer time spans. Compared with nonmusicians, musicians synchronized more accurately (heightened attunement), tapped more slowly (slower referent level), and used a wider range of hierarchical levels when instructed (enhanced focal attending), more often corresponding to the theoretically correct metrical hierarchy. We conclude that musicians perceptually organize events over longer time spans and have a more complete hierarchical representation of the music than do nonmusicians.

Previous psychological research investigating the perceptual and cognitive processes involved when listening to complex sound sequences is reorganized into a framework composed of four types of processes: two basic processes (segmentation into groups and regularity extraction) and two hierarchical organizations (hierarchical segmentation organization and hierarchical metrical organization). This framework allows us to propose hypotheses about the way these processes are acquired: the basic processes may be universal (functional from an early age and common to everyone), whereas the integration of these building blocks into hierarchical organizations may be acquired (through acculturation and specific training). We present illustrations from our recent work in support of these hypotheses.

Perceptual studies suggest that the segmentation of a musical sequence is influenced by three accent structures: rhythmic grouping, melodic, and metric accent structures. We investigate whether performers emphasize these types of accents with systematic performance variations (intensity, interonset timing, and articulation). In three experiments, skilled pianists performed sequences of various musical complexities: simple sequences containing only one accent structure (Experiment 1), more complex sequences containing coinciding or conflicting accent structures (Experiment 2), and a concert pianist's performance of a sonata containing coinciding and conflicting accent structures (Experiment 3). In all three musical contexts, similar systematic performance variations were observed in relation to each type of accent. Variations corresponding to rhythmic grouping accents were most consistent across musical contexts and dominated when the accent structures conflicted. These findings suggest perceptual correlates for the accent structures in music performance that may facilitate listeners' segmentation of musical sequences.

This paper examines the influence of three accent structures on the reproduction of simple musical tunes by 5-, 7-, 9-, and 11-year-old children and adult pianists. In the metric accent structure, periodically spaced beats are accented; in the melodic accent structure, events after a jump in pitch interval or after a turn in contour are accented; and in the rhythmic grouping accent structure, the first and last events of a rhythmic group are accented. Four themes were created in which all three accent structures coincided. Three variations were derived from each theme in which each accent structure in turn was moved out of synchrony with the other two. In a fourth variation, all three accent structures were out of synchrony with each other. Both the children's and the pianists' reproductions were the most accurate when the accent structures coincided and the least accurate when they conflicted. Intermediate results were obtained when the rhythmic grouping and melodic accent structures were displaced, but no deterioration in performance was observed when the metric accent structure was displaced, demonstrating the relatively unimportant role played by intensity variations in these conditions. These results were obtained only for the melody scores—no deteriorations were found in the rhythm scores. For the pianists, fewer errors were made on the accented notes than on the others. So, the juxtaposition of the three accent structures does indeed influence the perception of musical sequences. When attention is drawn to the same point in time by several different accent structures, the segmentation of the sequence into smaller units is efficient and reproductions are good. However, when attention is drawn to too many points in time, segmentation is less efficient and reproductions are poorer.