Wednesday, March 23, 2011

How Free Is Your Will?

Fascinating article in the realm of perceptual control theory...
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A clock face, advanced neurosurgery--and startling philosophical questions about the decision to act.
Scientists from UCLA and Harvard -- Itzhak Fried, Roy Mukamel and Gabriel Kreiman -- have taken an audacious step in the search for free will, reported in a new article in the journal Neuron. They used a powerful tool – intracranial recording – to find neurons in the human brain whose activity predicts decisions to make a movement, challenging conventional notions of free will.
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They had their patients look at a hand sweeping around a clock-face, asked them to press a button whenever they wanted to, and then had them indicate where the hand had been pointing when they decided to press the button. This provides a precise time for an action (the push) as well as the decision to act. With these data the experimenters can then look for neurons whose activity correlated with the will to act.
Such neurons, they found, abound in a region of the frontal lobe called the supplementary motor area, which is involved in the planning of movements. But here is the interesting thing: about a quarter of these neurons began to change their activity before the time patients declared as the moment they felt the urge to press the button. The change began as long as a second and a half before the decision, and as early as seven tenths of a second before it, this activity was robust enough that the researchers could predict with over 80 percent accuracy not only whether a movement had occurred, but when the decision to make it happened.
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Other interpretations might require that we reconstruct our idea of free will. Rather than a linear process in which decision leads to action, our behavior may be the bottom-line result of many simultaneous processes: We are constantly faced with a multitude of options for what to do right now – switch the channel? Take a sip from our drink? Get up and go to the bathroom? But our set of options is not unlimited (i.e., the set of options we just mentioned is unlikely to include “launch a ballistic missile”). Deciding what to do and when to do it may be the result of a process in which all the currently-available options are assessed and weighted. Rather than free will being the ability to do anything at all, it might be an act of selection from the present range of options. And the decision might be made before you are even aware of it. Think about that next time you reach for the remote.

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