Guy Kahane has a discussion of Utilitarianism and the Brain over at Ethics Etc. In particular, he is discussing Joshua Green’s fMRI studies of moral judgments that have claimed to distinguish between utilitarian and non-utilitarian thinking (and the latter claimed as more rational, the former more emotional and hence not quite as good). Kahane in particular pays attention to the methods used to generate the evidence and claims, and finds it wanting—the experimental scenarios themselves don’t clearly distinguish between the two types.
The debate has taken place in Nature, and here is a link to the actual text of the Nature critique by Guy Kahane and Nicholas Schackel as well as the response by Michael Koenig and colleagues.
Hat Tip: Natural Rationality