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If I raise my right arm, and I am suitably wired up, a peak occurs in the graph recording electrical activity in the brain just before I do so.
If I raise my left knee instead, the same thing : a peak in the graph.
Call these peaks readiness potentials.
The neurosurgeon called Libet has conducted experiments on this effect. (References in Dennett, Consciousness Explained, p162 ff.) He tried to investigate the relationship between the occurrence of that readiness potential and the person's decision - the decision made by the person to raise their left leg, raise their right arm or whatever.
So he tried to time when the decision occurred and when the readiness potential occurred.
So he asked his subjects: When I say Begin I want you in your own time to decide to raise your right arm. The moment you have made the decision look at the clock and tell me where the second hand is.
Meanwhile Libet monitored the brain activity and waited for the occurrence of the readiness potential.
So he was in a position to have a time for when the readiness potential went off, and a time for when the conscious decision was made.
What sort of a gap did he find?
How soon after the conscious decision was made did the readiness potential occur?
What would you expect?
A second or so?
A small fraction of a second?
The two occurred simultaneously?
How would you interpret this result?
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| Courtesy Blueyonder. |
Revised 14:01:03
