Phase correction, phase resetting, and phase shifts after subliminal timing perturbations in sensorimotor synchronization.

Recent studies of synchronized finger tapping have shown that perceptually subliminal phase shifts in an auditory sequence are rapidly compensated for in the motor activity (B. H. Repp, 2000a). Experiment 1 used a continuation-tapping task to confirm that this compensation is indeed a phase correction, not an adjustment of the central timekeeper period. Experiments 2-5 revealed that this phase correction occurs even when there is no ordinary sensorimotor asynchrony--when the finger taps are in antiphase or arbitrary phase relative to the auditory sequence (Experiments 2 and 3) or when the tap coinciding with the sequence phase shift is withheld (Experiments 4 and 5). The phase correction observed in the latter conditions was instantaneous, which suggests that phase resetting occurs when the motor activity is discontinuous. A prolonged phase shift suggestive of overcompensation was observed in some conditions, which poses a challenge to pure phase correction models.