In a study published Sunday in Nature Neuroscience, researchers using brain scanners could predict people's decisions seven seconds before the test subjects were even aware of making them. ...This is consistent with previous research, but it does not cast any doubt on free will. It just shows that it takes a few seconds to make a conscious decision.
Haynes updated a classic experiment by the late Benjamin Libet, who showed that a brain region involved in coordinating motor activity fired a fraction of a second before test subjects chose to push a button. Later studies supported Libet's theory that subconscious activity preceded and determined conscious choice -- but none found such a vast gap between a decision and the experience of making it as Haynes' study has.
In the seven seconds before Haynes' test subjects chose to push a button, activity shifted in their frontopolar cortex, a brain region associated with high-level planning. Soon afterwards, activity moved to the parietal cortex, a region of sensory integration. Haynes' team monitored these shifting neural patterns using a functional MRI machine. ...
Hallett doubts that free will exists as a separate, independent force.
I have noticed this myself while riding my bike. If I see a hazard in the road, I can slam on the brakes as fast as my reaction time will allow. Reaction time is usually a tenth of a second or so. But if I see something interesting on the side of the road and have to make a deliberate decision on whether to stop, then the decision takes a few seconds. I can only make a decision faster than a second if I had already prepared a programmed response.