A very interesting report of some research from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, in collaboration with the Charité University Hospital and the Bernstein Center for Computational Neuroscience in Berlin.
The researchers used a brain scanner to investigate what happens in the human brain just before a decision is made. Apparently, our brain makes a decision up to seven seconds before we become aware of it.
Participants in an experiment were asked to choose whether to push a button with their left hand or their right hand. They were allowed to decide well before they pushed the button, and were also asked to record at what point they felt they had made their decision.
In the seven seconds before Haynes' 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. Based on these brain patterns, the researchers were able consistently to predict which hand the subjects would use to push a button.
Taken together, the patterns consistently predicted whether test subjects eventually pushed a button with their left or right hand -- a choice that, to them, felt like the outcome of conscious deliberation.
So: does free will exist? I say, yes, it does. But our consciousness gets involved several seconds later. By the time we're aware of what we want to do, our brain and are body are already committed.