They asked 14 subjects to lie in a functional magnetic resonance imaging (fMRI) scanner, which allowed the researchers to track more brain regions for longer than Libet had. They instructed the subjects to decide spontaneously whether to press a button on the right or one on the left. The volunteers could decide at their own pace, but they had to report the moment of the conscious choice based on a clocklike device in the scanner.
The researchers scoured the brain for changes that correlated with the final decision. The earliest brain pattern that coded for a left or right choice was in the frontopolar cortex, right behind the forehead. The pattern predicted a left or right decision with about 60% accuracy and occurred about 10 seconds before the conscious choice, the team reports online this week in Nature Neuroscience. “We weren’t expecting this kind of lead time,” Haynes says. Even though the predictions weren’t perfect, “there’s not very much space for operation of free will,” Haynes says. “The outcome of a decision is shaped very strongly by brain activity much earlier than the point in time when you feel to be making a decision.” Haynes says the group hopes to extend the work to more realistic choices such as what to drink or what game to watch
via Case Closed for Free Will? — Youngsteadt 2008 (414): 3 — ScienceNOW.