Will you? Really? Touch your nose with your left forefinger. Go ahead. It's not a trick. I'll wait...
Okay. That was easy, right? You decided to touch your nose, and then you touched your nose. A simple, voluntary motion. Asked and answered.
[T]he new neuro-flavored debate over free will goes more like this: Is the feeling of will an illusion, a wily trick of the brain, an after-the-fact construct? Is much of our volition based on automatic, unconscious processes rather than conscious ones? ...
[T]he debate is still on, and near its center is an 86-year-old University of California professor emeritus of physiology, Benjamin Libet...
What Libet did was to measure electrical changes in people's brains as they flicked their wrists. And what he found was that a subject's ''readiness potential'' - the brain signal that precedes voluntary actions - showed up about one-third of a second before the subject felt the conscious urge to act.
The result was so surprising that it still had the power to elicit an exclamation point from him in a 1999 paper: ''The initiation of the freely voluntary act appears to begin in the brain unconsciously, well before the person consciously knows he wants to act!''
But, though controversial, the Libet experiments still stand and have been replicated. And they have been joined by a growing body of research that indicates, at the very least, that the feeling of will is fallible....
Among that research is the following experiment by Dr. Alvaro Pascual-Leone, director of the Laboratory for Magnetic Brain Stimulation at the Beth Israel Deaconess Medical Center.
A subject, he said, would be repeatedly prompted to choose to move either his right or his left hand. Normally, right-handed people would move their right hands about 60 percent of the time.
Then the experimenters would use magnetic stimulation in certain parts of the brain just at the moment when the subject was prompted to make the choice. They found that the magnets, which influence electrical activity in the brain, had an enormous effect: On average, subjects whose brains were stimulated on their right-hand side started choosing their left hands 80 percent of the time.
And, in the spookiest aspect of the experiment, the subjects still felt as if they were choosing freely.
''What is clear is that our brain has the interpretive capacity to call free will things that weren't,'' he said.
Confabulation, or the tendency of the brain to fill in details where conscious data is missing, is a well-known phenomenon. Obviously, where we can, we prefer to believe that we did things on purpose rather than randomly, under duress, or like automata. We cherish our sense of autonomy, purposefulness, and self-direction.
There are all sorts of ways of reading the information coming out of this area of research. If the "decision" lags the potentiation, why does that make it any less an act of will? The persons who flicked their wrists (or touched their noses!) still indisputedly did it at their own discretion. They may not have been able to mentally articulate the decision-making process ~ at the time that it took place ~ but that certainly doesn't mean they weren't deciding.
These are fascinating questions, at the very heart of the mind/body debate that has kept philosophers busy for a long, long time. I look forward with keen interest to more scientific research in this arena.
Read more of the Boston Globe article.
[via boing boing]
3:41:51 PM
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