Cf. Michaels et Rm. Bongers, THE DEPENDENCE OF DISCRETE MOVEMENTS ON RHYTHMIC MOVEMENTS - SIMPLE RT DURING OSCILLATORY TRACKING, Human movement science, 13(3-4), 1994, pp. 473-493
Four experiments examined the time taken to initiate a discrete moveme
nt of the fingers while performing rhythmical tracking movements with
an arm. Simple reaction time (RT - finger flexion to a tone) was measu
red at various phases of oscillations of the forearm as it tracked a v
isual stimulus either in phase or antiphase. In Experiments 1 and 2, d
iscrete responses were made by the oscillating hand, either parallel o
r orthogonal to the plane of motion of the oscillation. In both experi
ments, RT differed as a function of phase of the response cycle rather
than phase of the stimulus cycle. Experiment 3, which tested RTs at d
ifferent locations of a stationary hand, demonstrated that these diffe
rences are not attributable to the locations at which responses were s
olicited. Experiment 4 measured RT in a stationary right hand while th
e left hand oscillated; again dependence on response phase was observe
d. Tracking condition effects and frequency effects were interpreted i
n terms of the coupling of the arm as oscillator to the visual oscilla
tor; phase effects were interpreted in terms of the phase relation bet
ween the rhythmic action and the discrete action.