Perceived harmonic structure of chords in three related musical keys.

This study investigated the perceived harmonic relationships between the chords that belong to three closely related musical keys: a major key, the major key built on its dominant, and the relative minor key. Multidimensional scaling and hierarchical clustering techniques applied to judgments of two-chord progressions showed a central core consisting of those chords that play primary harmonic functions in the three keys. Th separation of chords unique to the keys and the multiple functions of chords shared by the different keys were simultaneously represented. A regular pattern of asymmetries was also found that suggests a hierarchy among different types of chords. In addition, there was a preference for sequences ending on chords central to the prevailing tonality. Comparison with earlier results on single tones points to differences between melodic and harmonic organization. The most striking characteristic of Western music is its harmonic structure, that is, the prevalent use of simultaneously sounded tones in chords. Indeed, music theory describes in detail the construction of chord sequences, the function of chords in establishing tonal organization, and the intimate connection between harmonic and melodic organization. There is no objective empirical basis, however, for this extensive literature on harmonic structures. Instead, music theorists attempt to characterize the common practice of composers in using chords in music. Nor have psychological studies on music addressed the question of how these harmonic properties are perceived. Virtually all earlier studies employing organized musical stimuli have used melodic sequences, that is, sequences of single tones (cf. Cuddy