Octave convergence in melodic perception

Previous research indicates that the pitch of a single tone can be conceptualized as a bidimensional quantity, reflecting the overall pitch level of the tone (tone height) and its position in the octave (tone chroma). It has been suggested that the dimension of tone chroma is irrelevant to perception of the component tones of a melody. Supporting this argument, perception of a melody is disrupted when its tones are displaced by octave multiples. This has been interpreted as showing that melodic perception is based upon the magnitude of successive pitch intervals. However, octave displacement violates both interval magnitude and direction. In the current study, melodies were subjected to structural transformations in which the tones were displaced by octave multiples, either preserving or violating the direction of successive pitch intervals (melodic contour). Replicating previous research, when melodic contour was violated performance was severely disrupted. When contour was preserved, however, the melodies were identified as accurately when the tones were displaced by octave multiples as when the melodies were untransformed. These results demonstrate that the bidimensional model of pitch perception applies to melodies, and that contour plays a significant role in melodic perception. [Work supported by NIMH.]