In the comments here, we've been discussing this April "neuropolitics" study in Current Biology, which was supported by the actor Colin Firth and actually lists him as a co-author. Another celeb science fan, one supposes. Anyway, it finds that in a sample of 90 young British men and women, the liberals and the conservatives tended to have somewhat different brain structures in brain scans. Conservatives had more gray matter in the amygdala, and liberals had more in the anterior cingulate cortex (ACC). The authors weren't shy about speculating as to what this means:
We speculate that the association of gray matter volume of the amygdala and anterior cingulate cortex with political attitudes that we observed may reflect emotional and cognitive traits of individuals that influence their inclination to certain political orientations. For example, our findings are consistent with the proposal that political orientation is associated with psychological processes for managing ...
