A runaway trolley is heading towards five workmen who are likely to die if you do not intervene quickly. If by pushing one person off a bridge you could save these five people from being killed by the runaway boxcar, would you try to save them? When hypothetically placed in the above moral predicament, most people are unlikely to reach a quick utilitarian judgment at the cost of actively harming a single individual (or a small group of individuals). Now a collaboration of seven researchers headed by Antonio Damasio, Professor of Neuroscience and Psychology at the University of Southern California (USC), provides evidence that patients with damage to the ventromedial prefrontal cortex (VMPC) are almost thrice as likely as "normal" people to make such utilitarian judgments. The VMPC is a part of the brain critically involved in the generation of emotion. The researchers hailed from California Institute of Technology, University of Iowa, Harvard University and USC; their results appeared online on March 21 at the Nature magazine Web site.

To examine the role emotions play in moral judgments, the researchers compared the response of six patients with damage to the VMPC to those of 12 normal individuals and 12 patients with damage to other parts of the brain not affecting emotions in hypothetical scenarios. Patients with damage to the VMPC have been documented to show reduced emotional receptivity, poorly controlled anger and frustration and diminished feelings of compassion, shame and guilt. However, these patients are normal in their intelligence, logical reasoning and understanding of social and moral norms of society.

Given the poor empathy showed by VMPC patients, the researchers reasoned that if emotions are indeed intricately involved in making moral judgments, VMPC patients should make utilitarian judgments at significantly higher rates than normal people when placed in (hypothetical) "personal" moral scenarios where, as the authors dub it, "aggressive welfare" measures need to be taken in emotionally averse circumstances (like, for instance, in the case of the runaway trolley with the person on the bridge). However, in "impersonal" moral scenarios and non-moral scenarios, requiring little emotional involvement, VMPC patients should show normal judgment patterns.

An example of a personal moral circumstance is as follows: imagine a runaway trolley is heading down a fork but this time you're inside it. On the left path there are five railway workers and on the right one railway worker who will die if you take their respective paths. If you do nothing, the trolley will take the left path and kill five people while if you intervene by hitting a switch, the trolley will proceed to the right and kill a single person. Would you hit the switch to save five people?

Indeed, when the questionnaire with hypothetical scenarios was evaluated, the three groups studied (normal, VMPC patients and other brain-damaged patients) showed no significant differences in their responses to non-moral and impersonal moral decisions. However, significant differences between VMPC patients and normal patients were obtained when personal moral questions were considered, with the former about three times as likely to choose outcomes that we might call utilitarian when compared to normal people and other brain-damaged patients.

The researchers believe their results suggest that the VMPC is critical for judging right from wrong, thereby necessitating the role of emotions in the generation of these judgments. Coauthor Ralph Adolphs, commenting on the findings, said that "the idea that emotions play a part in moral judgments is not new, but our study gives a stronger conclusion because it involves data from lesion subjects."

Professor of Neuroscience Steven George explained that the study shows that the VMPC "is a great example of what's called the 'modularity' of the brain, i.e. the fact that specific parts of the brain are associated with particular functions. We've known for a long time that basic functions are organized this way, e.g. different senses such as seeing and hearing are processed in different brain structures. This paper is striking in that it shows the modularity extending even to more complex functions such as emotions and social behavior."

The findings of the paper therefore support the notion that moral decision-making involves both emotions and a cost-benefit analysis. Professor William Zimmerman, a biologist at the College, explored the evolutionary reasons why utilitarian behavior, as displayed by VMPC patients in the hypothetical scenarios, has not been favored in normal people: "It could be argued that normal people are willing to throw a switch to save five by killing one, but unwilling to shove someone nearby to their death to save five because the latter action is risky: the person nearby may be thinking the same thing, so both are afraid to take the risk that they might themselves wind up dying. Also, in over 99.9 percent of human evolutionary history, the person standing next to you is very likely to be someone you know, that is, a member of your group, maybe a relative, and the five others down there, out of sight for individual recognition, may not be."

Professor Zimmerman also believes that a greater understanding of moral decision-making can be reached if the findings are interpreted in the light of human evolution: "An evolutionary view of moral reasoning and emotions suggests that they are evolved behavioral/mental adaptations for summing up potential costs and benefits to self, relatives and friends … In other words, moral emotions and reasoning-and their cultural manifestations of moral and legal systems, often sanctified/mandated by religious belief and authority-are a uniquely human adaptation (like language) for regulating the conflicts between the reproductive strivings of individuals (ultimately genes) in social groups. I think that such an approach makes it easier to [peel] the layers of complexity underlying human 'moral behavior' and figure out what is going on-for example in these experiments and observations."

Professor of Philosophy Alexander George, however, found the work to be "both confused and confusing." Elaborating on the study, Professor George stated that in his opinion the moral scenarios presented, in addition to being based on the self-evident truism that emotions play a critical role in moral judgment, tell us nothing about the moral judgments of VMPC patients: "[the] subjects were not asked what they thought they should do in these circumstances, but instead what they thought they would do …. They were asked to predict how they would act, and not asked to make a judgment about how they ought to act. Hence inference to conclusions about their moral judgments is unwarranted."

Professor Steven George summarized the findings by stating that while the science in the paper is "excellent and fascinating, … it doesn't take this paper to show … that the ultimate basis of human behavior is 'not reason alone,' [and that] convincing arguments to that effect were given by David Hume around 1740. Hume didn't use modern neuroscience techniques, obviously ... Hume did it by thinking carefully about what we mean by the concepts 'reason' and 'emotion.'"