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Abstract:
The first stage of this experiment replicates results
reported by Libet in 1985. Subjects reported becoming aware of
their decision to voluntarily initiate a simple finger movement at
least 300 ms. after the onset of the readiness potential (RP)
associated with the movement. Our results support Libet's
contention that conscious awareness of a decision to move is
preceded by cortical activity related to the movement. We conclude
that cortical processing of a simple voluntary decision is not
causally dependent upon consciousness of the decision. We also
describe a significant divergence between the EEG waveforms
recorded at C3 and C4, beginning at about the same time as the
subjects reported first becoming conscious of the decision to move
(approx. 200 ms prior to the movement). The goal for the second
stage of this experiment (currently in process) is to identify EEG
correlates of the conscious awareness of voluntary decisions.
Libet's original research was sharply criticized for its reliance
upon subjective, introspective reports of the timing of conscious
awareness. The second stage of our experiments will attempt to
improve upon Libet's original paradigm by eliminating the
dependence on subjective reports. Our discussion emphasizes
theoretical implications for the role of consciousness in voluntary
control, volition, and free will. JAP was funded by NIME
(MH54231-02)
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