Participants were asked to produce 30 successive intervals of 6, 12, 18, and 24 s with periodic finger taps aided by different mediators. During the presentation of the target and the production phase, they had to count or sing. The mean deviations from target were smaller in the counting condition than in the singing condition; training did not greatly improve performance; and the coefficients of variation (CV) increased with target durations. Large (r≈+.31) autocorrelations in the productions were caused by drifts toward faster tempi. Drift was a first-order (exponential) transition from tempi during presentation to asymptotic tempi during production. Our results show that a long series of productions may drift substantially and that, in this context, song mediated timing may drift more than count-mediated timing.

timing, counting, singing, sequential dependencies, interval production