The selective impairment of prosocial sentiments and the moral brain

Philosophers often describes the history of philosophy as a dispute between Plato (read: idealism/rationalism) and Aristotle (read:materialism/empiricism). It is of course extremely reductionist since many conceptual and empirical issues where not addressed in Ancient Greece, but there is a non-trivial interpretation of the history of thought according to which controversies often involves these two positions. In moral philosophy and moral psychology, however, the big figures are Hume and Kant. Is morality based on passions (Hume) or reasons (Kant)? This is another simplification, but again it frames the debate. In the last issue of Trends in Cognitive Science(TICS), three papers discusses the reason/emotions debate but provides more acute models.

Recently (see this previous post), Koenig and other collaborators (2007b) explored the consequences of ventromedial prefrontal cortex (VMPC) lesions in moral reasoning and showed that they tend to rely a little more on a 'utilitarian' scheme (cost/benefit), and less on a deontological scheme (moral do's and don'ts ), thus suggesting that emotions are involved in moral deontological judgement. These patients, however, were also more emotional in the Ultimatum game, and rejected more offers than normal subjects. So are they emotional or not? In the first TICS paper, Moll and de Oliveira-Souza review the Koenig et al. (2007a) experiment and argue that neither somatic markers nor dual-process theory explains these findings. They propose that a selective impairment of prosocial sentiments explains why the same patient are both less emotional in moral dilemma but more emotional in economic bargaining. These patients can feel less compassion but still feel anger. In a second paper, Greene (author of the research on the trolley problems, see his homepage) challenge this interpretation and put forward his dual-process view (reason-emotion interaction). Moll and de Oliveira-Souza reply in the third paper. As you can see, there is still a debate between Kant and Hume, but cognitive neuroscience provides new tools for both sides of the debates, and maybe even a blurring of these opposites.


References

• Moll, J., & de Oliveira-Souza, R. (2007). Moral judgments, emotions and the utilitarian brain. Trends in Cognitive Sciences, 11(8), 319-321.
• Greene, J. D. (2007). Why are VMPFC patients more utilitarian? A dual-process theory of moral judgment explains. Trends in Cognitive Sciences, 11(8), 322-323.
• Moll, J., & de Oliveira-Souza, R. (2007). Response to Greene: Moral sentiments and reason: friends or foes? Trends in Cognitive Sciences, 11(8), 323-324.
• Koenigs, M., & Tranel, D. (2007a). Irrational Economic Decision-Making after Ventromedial Prefrontal Damage: Evidence from the Ultimatum Game. Journal of Neuroscience, 27(4), 951-956.
• Koenigs, M., Young, L., Adolphs, R., Tranel, D., Cushman, F., Hauser, M., et al. (2007b). Damage to the prefrontal cortex increases utilitarian moral judgements. Nature, 446(7138), 908-911.