From Delancey Place:
Today's encore selection -- from This Is Your Brain on Parasites by Kathleen McAuliffe.
Revulsion and disgust at physical things -- such as overflowing toilets -- shares much of the brain's circuitry with moral outrage. Both are associated with the brain's anterior insula and amygdala. This may explain why moral judgments are so often coupled with disgust:
"Visceral disgust -- that part of you that wants to scream 'Yuck!' when you see an overflowing toilet or think about eating cockroaches -- typically engages the anterior insula, an ancient part of the brain that governs the vomiting response. Yet the very same part of the brain also fires up in revulsion when subjects are outraged by the cruel or unjust treatment of others. That's not to say that visceral and moral disgust perfectly overlap in the brain, but they use enough of the same circuitry that the feelings they evoke can sometimes bleed together, warping judgment.
"While there are shortcomings in the design of the neural hardware that supports our moral sentiments, there's still much to admire about it. In one notable study by a group of psychiatrists and political scientists led by Christopher T. Dawes, subjects had their brains imaged as they played games that required them to divide monetary gains among the group. The anterior insula was activated when a participant decided to forfeit his own earnings so as to reallocate money from players with the highest income to those with the lowest (a phenomenon aptly dubbed the Robin Hood impulse). The anterior insula, other research has shown, also glows bright when a player feels that he has been made an unfair offer during an ultimatum game. In addition, it's activated when a person chooses to punish selfish or greedy players.
"These kinds of studies have led neuroscientists to characterize the anterior insula as a fountainhead of prosocial emotions. It is credited for giving rise to compassion, generosity, and reciprocity or, if an individual harms others, remorse, shame, and atonement. By no means, however, is the insula the only neural area involved in processing both visceral and moral disgust. Some scientists think the greatest overlap in the two types of revulsion may occur in the amygdala, another ancient part of the brain.
"Psychopaths -- whose ranks swell with remorseless cold-blooded killers -- are notorious for their lack of empathy, and they typically have smaller than normal amygdalae and insulae, along with other areas involved in the processing of emotion. Psychopaths are also less bothered than most people by foul odors, feces, and bodily fluids, tolerating them -- as one scientific article put it -- 'with equanimity.'....
....MUCH MORE
