Tracking time with song and count: different Weber functions for musicians and nonmusicians.

Participants reproduced target intervals of 6-24 sec with finger taps, with target intervals presented before each of 30 reproductions. During the presentation of the target and reproduction, nonmusician participants were asked to count, sing, or do nothing. In another part of the experiment, musicians were asked to count or sing. Segmentation, either by song or count, minimized deviations from targets and reduced the coefficient of variation (CV) to one third of the nonmusicians' CVs in the no-segmentation condition. The mean deviation from target was significantly lower for musicians than for nonmusicians, as were the musicians' CVs (half the value of the nonmusicians). Most importantly, although the CV of nonmusicians was invariant over the range of intervals conforming to a strict scalar property, it decreased significantly for musicians as target intervals increased.