Synchronization performance under such conditions is described well by the Wing- Kristofferson two- level model (Wing & Kristofferson, 1973) augmented by a linear phase- error correction mechanism (Pressing, 1998; Vorberg & Schulze, 2002). A central notion is the assumption of an internal timekeeper that controls the interval between taps and triggers the motor system correspondingly. Error correction is necessary because the timekeeper and the motor system are subject to temporal jitter; without correction, the produced taps and the metronome sequence will run out of phase. Alinear error- correction mechanism that uses the asynchronies between taps and metronome clicks for corrective phase shifts without changing the timekeeper period gives an excellent account of synchronization performance when the metronome’s period is constant and when it is subject to small perturbations (Semjen, Vorberg, & Schulze, 1998; Semjen, Schulze, & Vorberg, 2000; Repp, 2000, 2001).