Production and synchronization of uneven rhythms at fast tempi

THIS STUDY EXAMINED PRODUCTION an d synchro- nization of eight uneven rhythms (set A: 2 3, 3 2; set B: 2 2 3, 2 3 2, 3 2 2; set C: 2 3 3, 3 2 3, 3 3 2) at rates that made it difficult to subdivide the component intervals into elementary metrical pulses. The main questions were how interval ratios would change as a function of tempo within this range, and wh ether metrical downbeat location (which distin- guishes the rhythms within each set) would be reflected in any of the dependent measures. Musically trained participants tapped each rhythm cyclically in syn- chrony with an auditory template and then continued to tap in three ways: self-paced, paced by a sequence of downbeats, or paced by a rapid stream of isochronous subdivisions. Each task was carried out at eight tempi. The third task assessed the temporal limit of subdivi- sion for these rhythms (about 6 Hz), which was exceeded by most tempi. Results showed that the mean long–short (3:2) interval ratio was already larger than 1.5 at the slowest tempo in rhythm sets A and B, and increased with tempo in sets B and C, but did not appr oach 2. Uneven rhythms thus can be produced without mental subdivision, but only with substantial enhancement of the contrast between long and short intervals. Metrical downbeat location had no reliable effect on interval ratios but was reflected in more force- ful downbeat taps and in different alignments of taps with a pacing sequence. In general, effects of temporal grouping (between rhythm sets) outweighed those of metrical interpretation (within rhythm sets)