Annotation for Lerdahl, Fred, and Jackendoff, Ray

A Generative Theory of Tonal Music

Annotation (by Bill Tilghman):

Combining the formal methodology and psychological concerns of Chomskian linguistics with the insights of Schenkerian music theory, the authors attempt to describe how a listener experienced in the tonal idiom intuitively creates an understanding of a complete musical structure. Restricting themselves to those aspects of musical intuition that they consider hierarchical in nature, Lerdahl and Jackendoff divide their theory into four main components: grouping structure, metrical structure, time-span reduction, and prolongational reduction. Each component is first exposed informally (Chapters 2, 5-6, and 8) and then expressed as a logically rigid set of "rules" of "musical grammar" (Chapters 3-4, 7, and 9). The latter consist of both well-formedness rules, which describe the minimal conditions for an intuitively understandable structure, and preference rules, which correspond to the intuitions that allow a listener to choose the preferred interpretation of the structure from all of the possible ones that conform to the well-formedness rules.
The distinction between grouping structure and metrical structure is essential to Lerdahl and Jackendoff's conception of musical rhythm. The metrical structure, which exists only at levels relatively near the surface, is articulated by the regular hierarchical pattern of metrical accent, a psychological construct extrapolated from (but not necessarily identical to) the patterns of phenomenal accent in the music itself. The grouping structure reflects the listener's recursive segmentation of the musical continuum into progressively larger units, whose boundaries do not necessarily coincide with metrical accents. At larger levels, grouping boundaries are articulated by structural accents, and it is these structural accents that are heard as rhythmically important enough (as reflected in the time-span reduction) to participate in the larger prolongational structures.
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