I agree with much of what Michael Gazzaniga says here, and with the overall thrust of the project exemplified most recently in his book Who’s in Charge?: Free Will and the Science of the Brain.

http://c.brightcove.com/services/viewer/federated_f9?isVid=1&isUI=1

However, as much as we might like to make this project entirely palatable, there is an important sense in which it does seem to challenge some stubborn intuitions, and I think we need to recognize the fact that such findings can and do influence our ideas about how and when to hold people responsible. The clearest evidence for this is found in the legal realm where, from the insanity defence to the twinky defence, we encounter a long history of attempts to grapple with the relation between the apparently mechanistic nature of the brain and our ability to hold people responsible for their actions–attempts which clearly show that a scientific-mechanistic understanding of the brain has important bearing on our understanding of freedom and agency.