Using fume-fume and bembé rhythms to study pitch-time interactions and a method for experimentally probing rhythmic hierarchies
The theoretical isomorphism between the fume-fume rhythm and the pentatonic scale, and between the bembé rhythm and the diatonic scale, provides an opportunity to study whether pitch and time interact in perception. We studied this by constructing combinations of all rotations of the rhythms and all rotations of the scales (5×5 and 7×7, respectively). Western listeners judged, for each combination, how well the rhythm fits the scale. The question we next asked was whether these fit judgments could be accounted for by the coincidence of tonal and rhythmic hierarchies. To assess this, we used the standard probe tone technique to find the tonal hierarchies for each rotation of the pentatonic and diatonic scales. We developed a method for experimentally probing rhythmic hierarchies by dynamically accenting each event in each rotation of the fume-fume and bembé rhythms. A clear pattern was found for the bembé rhythm and the diatonic scale combinations, with the fit ratings covarying with the coincidence of tonal and rhythmic hierarchies. The same result was found only for participants reporting familiarity with the fume-fume rhythm and the pentatonic scales, suggesting the desirability of cross-cultural extension of the study.