The perceived similarity of auditory polyrhythms.

Abstract

This experiment explored the structural representation of rhythm by having subjects rate the similarity of pairs of polyrhythms. Three different polyrhythms were employed (3×4, 3×5, and 4×5). Although subjects were instructed to ignore pitch, two types of pitch information (pitch proximity and tonal relatedness) were varied between the tones defining the polyrhythms in order to assess their influence on the similarity space of the rhythms. The results showed that, independently of pitch, some rhythm combinations were considered more similar than others. Pitch information had a uniform effect on polyrhythm similarity, systematically increasing or decreasing the similarity among all rhythms by roughly the same amount. This suggests that pitch information may have been processed independently of rhythmic information, and that only at another stage in processing is information from the two dimensions integrated.