Grouping Hierarchy and Trajectories of Pacing in Performances of Chopin’s Mazurkas

[1] The last three decades have seen a growing interest in the slight beat-to-beat changes in duration that pervade performances of tonal music. Many current approaches originating in the work of music psychologists interpret durational variability as the means by which performers convey both segment boundaries and hierarchical relationships between segments. But these approaches depend on a one-way mapping from a single grouping-structural analysis onto performed durations, a mapping at odds with the possibilities for interpretive difference that are increasingly acknowledged in music analysis (Cook 1999).[2] In this article, after expositing how performers can suggest novel descriptions of grouping structure by lengthening group-final events (Sections I and II), I will introduce a method grounded in contour theory for determining the relative salience of hierarchically nested groups in a particular recorded performance (Section III). I will then argue that shifts in the level of grouping structure presented as most salient affect the perceived pacing of a piece (Section IV). In later analyses, I will show how performers can address contrasts in pacing, or trajectories in pacing, latent in two of Chopin's mazurkas (Section V). By introducing an analytical method that begins with the particularities of a phrase as it is performed, I hope to demonstrate one way in which performance can affirm, nuance, or even circumvent a grouping structure implied by a score.I. Introduction: Performance, Segmentation, and Musical Flow[3] Since the 1980s, music psychologists have explained durational variability in performances of tonal music largely through a phenomenon termed "phrase-final lengthening," a means of conveying grouping structure by decelerating at the ends of groups (Bengtsson and Gabrielsson 1980; Todd 1985; Palmer 1989). Because the word "phrase" in this usage refers to a linguistic rather than musical unit, I'll refer to this practice as "group-final lengthening," hereafter GFL. Scholars also recognize that not all lengthenings are responses to grouping structure: meter, melodic contour, and ornamentation also affect beat durations (Gabrielsson and Bengtsson 1983; Friberg, Bresin, and Sundberg 2006; Desain and Honing 1994). Since performance timing is inherently multivariate, earlier work (especially Todd 1985) tends to construe timing decisions in individual performances as a "signal" of grouping structure conveyed through the "noise" of local effects such as meter or melodic contour. Furthermore, performers may use multiple strategies to convey the same grouping-structural interpretation. One might emphasize an event by lengthening it or by lengthening the preceding event that anticipates it (Clarke 1988, 15). Therefore models of performance timing that take a single determination of grouping structure and return an expected timing profile can be deemed robust even if timing profiles in actual performances vary considerably.(1)[4] The grouping structure thought to be conveyed through performance timing amounts to a segmentation of a piece. Yet this idea that tempo variation in performance primarily communicates grouping structure disregards two key aspects of musical segmentation. First, as Dora Hanninen (2001, 351) points out, music presents a variety of potentially conflicting criteria relevant to segmentation, and thus multiple segmentations are always possible depending on differences in the predilections and aims of performers and analysts. Second, because grouping structure in music can be represented as hierarchical, both the locations of group endings and their hierarchical relationships are subject to interpretation. In the extant models of performance timing, the relationship between timing, the interpretability of grouping structure, and grouping-structural hierarchy has not been adequately addressed.Example 1a. Frederic Chopin, Mazurka in C major, op. 24, no. 2, measures 21-28, score excerptExample 1b. …