Monday, July 07, 2008

Unconscious brain has already decided

On average, the volunteers took about 22 seconds to press the button and felt that they consciously decided to do so about a second or less before they made the movement. But the fMRI data told a much different story. Two parts of the brain - the frontopolar cortex and the precuneus - showed activity that predicted the choices that the volunteers made and in the frontopolar cortex, this activity happened a whopping 7 seconds before the subjects were consciously aware of their decisions.

These astonishing results suggest that by the time we become consciously aware of a decision to move, our choices have already been influenced for several seconds by the actions of the frontopolar cortex. The study goes well beyond Libet's original work. It shows that this preliminary activity is far from a general and non-specific curiosity, but can actually predict a decision. Nor can it be explained away by inaccuracies in measurement - the timescales involved were far too long for that.

Another take here.

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