Minding the gap: An experimental assessment of musical segmentation models.

Music and language are parallel in many respects (for overviews, see Besson & Friederici, 1998; Patel, 2010), including their origins and historical development (Wallin, Merker, & Brown, 2000), patterns of development across the life span (Drake, 1998), and elements of cognitive processing (Swinney & Love, 1998). Although music and language are different types of stimuli and utilize different cognitive operations (Patel, 1998; Peretz, 1993; Peretz et al., 1994), they appear to share several structural properties (Blacking, 1973; Krumhansl, 1998; Lerdahl & Jackendoff, 1983; Raffman, 1993; Sloboda, 1985). For example, in music and in language, structural rules specify how combinations of smaller units form larger structural frameworks (e.g., notes forming melodies, words forming sentences). However, structural properties of music are more ambiguous and fluid than are structural properties of language (Jackendoff & Lerdahl, 1981; Jescheniak, Hahne, & Friederici, 1998), and the specific structural rules by which a listener might segment a larger musical stimulus into smaller meaningful units are not entirely clear. To better understand the process of musical segmentation, the experiments presented here provide an empirical evaluation of structural rules suggested by two different models of music cognition: the perceived phrase structure model (PPS; Temperley, 2001) and the generative structural grammar of music model (GSGM; Lerdahl & Jackendoff, 1983). Based in part on the notion of generative structural grammars in language (Chomsky, 1965, 1968, 1957/2002; Yngve, 1960), analogous generative structural grammars have been proposed for music (Deutsch & Feroe, 1981; Lerdahl & Jackendoff, 1983; Tenney & Polansky, 1980; Winograd, 1968). The unit of the motif, which can be as small as two notes, is important both structurally and psychologically (see Jackendoff & Lerdahl, 1981; Zbikowski, 1999). Generative grammars combine these motifs into basic phrase units to form the lower level of a hierarchical structure (see Gregory, 1978; Johnson, 1965; Rosenberg, 1968, for empirical support for the functional use of such a structural grammar). Given the fundamental importance of the phrase, and the importance of understanding basic units before proceeding to more complicated hierarchies based on combinations of those basic units, the focus here will be upon segmentation within a local context (i.e., on phrase-level context rather than on extended and hierarchically organized context). To wit, we assessed how participants determine phrase boundaries in musical stimuli and segment those musical stimuli into meaningful parts. There is a paucity of literature assessing segmentation models in diverse (i.e., experienced and inexperienced listener) human (i.e., nonmachine) populations. The relative novelty of our study lies within the populations that we studied and the hypotheses that we tested. Specifically, we studied humans with a range of musical experience and compared their segmentation responses with theoretical segmentation points generated by two prominent musical segmentation theories.The GSGM model is a prominent and influential theory that proposes several grouping preference rules for determining the locations of local context phrase boundaries in music (see Table 1). The GSGM model suggests that when one or more of these grouping rules is fulfilled, then perceived segmentation (i.e., perception of a phrase boundary) typically occurs. The rules are not mutually exclusive, and different rules can be combined to create different strengths or levels of segmentation. Deliege (1987) examined the extent to which perceptual grouping corresponded with the local context segmentation rules of GSGM for a group of listeners. Deliege presented short musical excerpts, and musician or nonmusician participants indicated the point at which they heard natural breaks in the music by drawing a vertical line in a row of horizontally oriented dots in which successive dots represented successive notes. …