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5/4/08

Benjamin Libet & Free Won't**


Hold out your arm. Look at it. Now bend your hand at the wrist. Do it whenever you want. Do it a few times.*

How did this process begin? Was it you? Was it these words?

In 1985, neuro-scientist Benjamin Libet conducted an experiment related to this.

With electrodes connected to their wrists and scalps, his subjects had brain waves recorded as they watched a clock with a spot revolving faster than a second hand. Like you, they were told to flex their wrists whenever. They were also told to note the spot's position at the time they decided to do so. They stated where they saw it, and Libet correlated their observations with data recorded by electrodes at wrist and scalp.

Libet measured three factors: the action's beginning, the moment of decision, and the Readiness Potential, which began a certain brain wave pattern. This pattern involves the brain's plans to carry out an action.

Okay, so what did he find out? This. The decision to act was recorded as taking place at some 200 milliseconds before the Readiness Potential, which occurred some 550 milliseconds before the action.

So what?, you ask. Only this. A decision to act did not start the process. It did not come before the Readiness Potential. It can be construed as an effect of the Potential as cause. The decision was determined, then, and not a function of free agency.

Surprised? Did you expect a different sequence, this one?: first, the decision to act, then the planning stage, otherwise known as Readiness Potential, followed by the action. Instead, the Readiness Potential preceded the decision. Understood one way, no decision caused the brain to get ready to act. The brain got ready, then gave the appearance that a decision was made.

Some who study this experiment can liken the sense of decision to a hood ornament over a truck engine, symbolic rather than instrumental of a driving force. Libet found one, Readiness Potential, two, decision, three, action. The Readiness Potential led to the action, with the decision to act as a result of the Readiness Potential. In their view, with true free will a decision should have generated the preparation to act, culminating in the Readiness Potential.

Others say that had the decision sprung into consciousness without anything preceding it, the event would have been like God in the Book of Genesis saying of the void, Let there be light! Something would have come out of nothing. We can deem it natural that something comes from something, in this case a decision from a Readiness Potential. Obvious proponents of something from something are scientific determinists. This handily dispenses with subject-object duality and explains all through a physical monism.

With a different argument, somebody might say that a neatly simple scientific experiment causes reductionist absurdity when applied to anything so complex as human agency—or free will, if you prefer. People daily engage in behavior more complex than moving their wrists. They raise children, handle office politics, respond to political news. These involve conscious experiences, not simple brain events which the Libet experiments record. The correlation of conscious experience to brain events is highly problematic.

Still, one interpretation is that while Libet's subjects thought they were deciding, they actually saw an internal replay of a decision that had already occurred. They did not initiate an action but thought they had. They thought their decision had caused the action, although the Readiness Potential may have caused the decision to act. No choice, here, they would argue. No volition, just a series of processes.

If Libet's subjects didn't have free will, they did have a kind of free won't. That is, he told them that they could veto an action. Instead of flexing a wrist, they could stop the movement. He discovered an action could be vetoed, but the subjects only had one tenth second (100 milliseconds) to do so. In short, they could not initiate an action and could only overrule any impulse if they were alert and acted instantly. This is reminiscent of Zen teachings about alertness as the road to freedom.

(Of this experiment, and its implications, Tufts University philosopher Daniel Dennett* is reputed to have said "I want more freedom than that." *(Freedom Evolves, Elbow Room, Consciousness Explained, and other books.) In short, this does not mean he refuses to accept the facts but believes that they can be interpreted differently.)*( Slightly revised from a 2003 post.)

** Jeff Miller and Judy Trevena of the University of Otago in Dunedin, New Zealand. have conducted experiments that call into question Libet's findings. According to their view, the Readiness Potential only pays attention to decisions being made and does not mean that one is "decisionally" aware of his action after the fact. In short, the Readiness Potential is misconstrued as to its role.

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