Perception of Pitch and Time in the Structurally Isomorphic Standard Rhythmic and Diatonic Scale Patterns

Abstract

The three experiments reported here investigate how pitch and time interact in perception using the standard rhythmic pattern and the diatonic scale pattern, which share the intervallic structure of 2 2 1 2 2 2 1. They share a number of theoretical properties, including being cyclic with seven unique rotations. Experiment 1 measured rhythmic stability by dynamically accenting each of the events in each rhythm, called the probe accent; listeners rated how well the probe accent fit the rhythm. Listeners heard the rhythms in subgroups and with reference to a syncopation-shifted metrical hierarchy. Experiment 2 used the probe tone technique to measure the tonal stability of each tone in each mode beginning and ending on C. Higher ratings were given to tones earlier in the contexts and tones closer to C on both the chroma circle and the circle of fifths; influences were also found of tonal hierarchies of diatonic scales with corresponding accidentals. A measure of similarity derived from the probe ratings found the same order for the rhythms and modes which matched theoretical proposals of inter-rhythm and inter-mode distances. Experiment 3 presented all combinations of rhythms and modes; listeners judged how well the rhythm fit the mode. These judgments did not depend on the intervallic isomorphism between tone duration and interval size. Instead, the judgments depended on whether tonally stable events occurred where accents were judged as fitting well with the rhythm. Overall, the standard and diatonic patterns follow different perceptual hierarchies while sharing similar cognitive principles between rhythms, between modes, and across dimensions.