Dimensions of specificity in musical memory: Evidence from metrical restoration

Dimensions of specificity in musical memory: Evidence from metrical restoration Sarah C. Creel (creel@cogsci.ucsd.edu) University of California, San Diego, Department of Cognitive Science La Jolla, CA 92093-0515 Abstract On first glance, a simple answer to both questions is degree of similarity: listeners generalize to similar musical patterns, and maintain specific representations of less-similar patterns. However, determining equivalent degrees of similarity on varied dimensions is not trivial, as perceivers’ use of dimensions can change depending on task and attentional factors (Nosofsky, 1986). That is, we do not know what weights listeners assign to different dimensions in musical memory. Further, some dimensions may be processed integrally, such that their combined effect is not a simple sum of their individual effects. The current study aims to explore the relative strength of various auditory- musical properties on metrical restoration, providing insights into similarity-based organization in musical memory. How is musical memory organized? While classic studies of music perception appealed to schematic or symbolic knowledge structures, recent work suggests that listeners form highly-detailed auditory representations of music. Studies of metrical restoration—memory fill-in of the “beat” of a metrically-ambiguous melody—suggest some organizing dimensions in musical memory. However, many potential dimensions remain unexplored. The current study looked for effects of mode (major vs. minor)—a substantial organizing force in Western music—and timbre (what instrument is playing) on metrical restoration. Both mode and timbre can signify particular musical styles. In Experiment 1, listeners showed timbre specificity in metrical restoration, but not mode specificity. However, in Experiment 2, when timbres were extremely unique (one per melody), restoration effects were not observed, suggesting that too much variability leads to diffuse representations which are too weak to support metrical restoration. Implications for the nature of musical memory are discussed. Keywords: perceptual restoration, meter, music perception, metrical restoration Introduction Recent research suggests that listeners form rich, detailed representations of perceptual information. These details later facilitate recognition (Creel, Aslin, & Tanenhaus, 2008; Goldinger, 1998; Gjerdingen & Perrott, 2008; Krumhansl, 2010; Schellenberg et al., 1999) and allow fill-in of ambiguous or absent information (Creel, 2011, 2012; Samuel, 1981). In music particularly, Creel (2011, 2012) has shown that listeners who hear particular metrical (or harmonic) information with a melody will later, upon hearing the melody alone, fill in the missing contextual information (harmony or meter) previously heard with that melody. These findings are interesting in a number of respects. First, meter is a property previously thought to be largely signal-driven, with listeners extracting metrical regularities via statistical analysis of the signal itself. Creel’s work suggests that memory influences meter perception. Second, these findings suggest that similarity-based organization of detailed auditory-temporal memories can support knowledge of distinct genres, such as different musical styles or different languages. Yet many questions remain. What factors allow listeners to keep particular musical patterns distinct in memory— what keeps them from bleeding together? Inversely, what factors allow listeners to generalize metrical information? Figure 1. First four measures of a melody, in (a) major key with 6/8 metrical context; (b) minor key with 3/4 metrical context. Metrical grids indicate perceived emphasis in each meter: large X’s denote strong beats, small x’s weaker beats, and . ’s indicate the subdivision of each beat. Beat subdivisions are identical in duration in both versions. Known influences on metrical restoration Previous work in my lab (Creel, 2011, 2012) has examined some factors in memory restoration of meter. In those experiments, as well as the new experiments described here,