Nature Reviews Neuroscience 9, 934-946 (December 2008)
Human volition: towards a neuroscience of will
Patrick Haggard, Institute of Cognitive Neuroscience
Here's the abstract:
The capacity for voluntary action is seen as essential to human nature. Yet neuroscience and behaviourist psychology have traditionally dismissed the topic as unscientific, perhaps because the mechanisms that cause actions have long been unclear. However, new research has identified networks of brain areas, including the pre-supplementary motor area, the anterior prefrontal cortex and the parietal cortex, that underlie voluntary action. These areas generate information for forthcoming actions, and also cause the distinctive conscious experience of intending to act and then controlling one's own actions. Volition consists of a series of decisions regarding whether to act, what action to perform and when to perform it. Neuroscientific accounts of voluntary action may inform debates about the nature of individual responsibility.
I always get a bit nervous when scientists and especially neuroscientists start talking about the will and responsibility, because they so often start making big claims -- such as Libet denying free will. I also am skeptical that neuroscientists can tell us anything of moral or philosophical significance regarding free will. I've often liked the work of Stephen J. Morse at PennLaw who has cast doubt on the helpfulness of neuroscience in understanding criminal responsibility.
Nevertheless, I haven't yet found any a priori arguments that neuroscience must be useless in understanding free will and responsibility, and I can imagine that when used in conjunction with a sophisticated philosophical theory, the work of neuroscience would actually be very illuminating. The work of other psychologists, such as Roy Baumeister on ego depletion, has been used to great effect by Richard Holton and Neil Levy, has been used to illuminate our understanding of weakness of will, to give just one recent example. So I'm looking forward to reading Haggard's article.