MOTOR DISRUPTION IN THE PRODUCTION OF TIME INTERVALS WITH FINGER TAPS

Two experiments examined the variance associated with the motor compon ent in a time production task involving a series of finger taps. Use o f the segmentation strategy described by Grondin (1992) allowed the is olation of a part of the variance associated with the motor component in such a tapping task. It is shown that replacing a finger tap by an internal indicator reduces the coefficient of variation by about .5% p er second. As well, these experiments showed that the choice of subint ervals, when an interval is segmented during a timing task, is a major source of variance. It is concluded that the segmentation strategy pr ovides a general framework for analyzing the part of the variability p rovoked by each of two components - the clock and the motor system - i nvolved in a time interval production task.