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Abstract:
Abstract: During repetitive finger tapping, the temporal
consistency of each hand is reduced during bimanual performance
compared to unimanual tapping with either the dominant or
non-dominant hand. This within-effector improvement is robust and
can be obtained with various limb combinations (e.g., finger-foot).
To account for this effect, we have proposed a multiple timer model
(MTM) in which the temporal improvement is due to the integration
of independent timing signals associated with each effector. By
this model, timing and temporal coupling are dissociable processes:
One process is associated with generating the temporal control
signals to indicate when successive movements should occur and a
second process constrains the implementation of these commands so
that they occur in synchrony during bimanual movements. A set of
novel predictions derived from the MTM were confirmed in the
current behavioral experiments. First, the reduced variability
during bimanual movements should not require repetitive movements.
As predicted, the reduction was also found when participants
produced single intervals. Second, the reduction of variability
during bimanual tapping should interact with interval duration such
that the effect was larger for longer intervals. This prediction
was confirmed in an experiment in which participants tapped at
rates ranging from 325 ms to 625 ms under both unimanual and
bimanual instructions. Moreover, the phase differences between the
two hands were similarly distributed across target interval,
consistent with the predictions of the MTM.
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