The MRI of morality?

Greg Miller reviews research on the nature of human morality which continues to probe the debate between the views of of David Hume - that emotions drive moral judgments - and Immanuel Kant - who argued that reason should be the driving force. He includes reference to a recent study by Hsu, Anen, and Quartz on equity and efficiency. Some clips, from from the Miller review, and then the Hsu et al paper:

One research group:

...asked dozens of college students to consider several morally charged situations. In one, a friend lies on his résumé to land a job; in another, survivors of a plane crash consider cannibalizing an injured boy to avoid starvation. Students who pondered these hypothetical scenarios while sitting at a filthy desk with sticky stains and a chewed-up pen rated them as more immoral than did students who sat at a pristine desk. In another version of the experiment, a nearby trash can doused with novelty fart spray had a similar effect. The findings...demonstrate that emotions such as disgust exert a powerful influence on moral judgments, even when they are triggered by something unrelated to the moral issue.

Hsu et al. consider distributive justice, illustrated by the following example:

Imagine driving a truck with 100 kg of food to a famine stricken region. The time it would take you to deliver food to everyone would cause 20 kg of food to spoil. If you delivered food to only half the population you would lose only 5 kg. Do you deliver the food to only half the population to maximize the total amount of food, or do you sacrifice 15 kg to help everyone and achieve a more equitable distribution?

They examine the the tradeoff between equity and efficiency, finding:

...that the putamen responds to efficiency, whereas the insula encodes inequity, and the caudate/septal subgenual region encodes a unified measure of efficiency and inequity (utility). Strikingly, individual differences in inequity aversion correlate with activity in inequity and utility regions. Against utilitarianism, our results support the deontological intuition that a sense of fairness is fundamental to distributive justice, but, as suggested by moral sentimentalists, is rooted in emotional processing. More generally, emotional responses related to norm violations may underlie individual differences in equity
considerations and adherence to ethical rules.

Neuroimaging studies have linked several brain regions to moral cognition. Disruptions to the right temporoparietal junction (brown), which is involved in understanding intentions, or the ventromedial prefrontal cortex (green), which processes emotion, have been found to alter moral judgments... activity in the anterior cingulate cortex (pink) may signal conflict between emotion, reflected by activity in the medial frontal gyrus (blue) and other areas (orange, brown), and "cold" cognition, reflected by activity in dorsolateral prefrontal cortex (yellow).