Adding drift to the decomposition of simple isochronous tapping: an extension of the Wing-Kristofferson model.

The Wing-Kristofferson model (A. M. Wing & A. B. Kristofferson, (1973a, 1973b) decomposes the variance of isochronous finger tapping into 2 components: a central clock component and a peripheral motor component. The method assumes that there is no drift in the intertap intervals. A new method is introduced that further decomposes the clock component drift and drift-free clock variance. The method was studied through simulation and empirical analyses. Clock variance was the most prominent, followed by drift, and then motor variance. Individual and group differences were larger for the motor and drift variances than for the drift-free clock variance, so that group differences observed in the past may have been partially due to the failure to fully remove drift. The authors argue that the methods presented and extensions thereon show great promise in extending a method in wide use since 1973. (c) 2004 APA, all rights reserved