Disgust and Social Tolerance

From the Edge 2007 Question of the Year, “What are you optimistic about?” Marc Hauser answered with the hopeful idea of eliminating “isms” and prejudice against social groups, armed with knowledge obtained from brain science. For instance, the neurodegenerative changes that occur in people with Huntington’s disease cause an inability to feel disgust – which can be provoked by racism, sexism, ageism, etc. Perhaps we can benefit from neuroscience by studying this change in the brain and its relation to feelings of disgust.

As well, a recent neuroimaging study mapped responses to images of people from distinct social identity groups, along with reactions to inanimate objects. The area involved in social cognition lit up with fMRI while looking at people except with pictures of the homeless, and drug addicts, suggesting dehumanizing. Object images that tested similarly (disgust) on the parallel scale were vomit and an overflowing toilet.

But optimistically, Hauser’s three-point answer hopes to reduce disgust:

Be vigilant of disgust!

The most virulent of human emotions is disgust. Although disgust was born out of an adaptive response to potential disease vectors – starkly, things that are normally inside but are now outside such as vomit, blood, and feces – it is a mischievous emotion, sneaking into other problems, alighting, wreaking havoc on group structure, and then spreading. Throughout the history of warfare, every warring group has tagged their enemy with qualities that are reminiscent of disease, filth, and parasites. The imagery is overwhelming, beautifully designed to trigger the rallying cry. Though the destruction of 6 million Jews by the Nazis was made possible by an extraordinary advertising campaign, it was made all the more possible by the carefully crafted manipulation of disgust: in the Nazis’ hands, the Jews were vermin, dirty, diseased, and thus, disgusting. Wouldn’t we all be better off without disgust? What if we could remove this emotional card?

Would we knock the sails out of our efforts to denigrate the other? Intriguingly, there are some people who never experience disgust and don’t recognize it in others, even though they experience and recognize all of the other familiar emotions – sadness, happiness, fear, surprise, anger. These people are carriers of the genetic disorder Huntington’s Chorea. Though they suffer from significant deterioration of the motor systems, they are disgust-free. So too are carriers that are pre symptomatic. Although we don’t know whether patients with Huntington’s are immune to the nefarious propaganda that might come their way should someone wish to foist their prejudices upon them, my hunch is that science will confirm this relationship. And if that is the case, perhaps modern molecular techniques will one day find a way to cure Huntington’s, but along the way, work out a method to crank down or turn off our disgust response, while preserving our motor systems.

This is a playbook for today. It is not a final solution. It provides, I believe, a breadth of hope that someday we may see greater peace in this world, greater respect for the other.

A reduction in disgust, stigma and prejudice is wonderfully optimistic.

Read more Edge.
Read Dehumanizing the Lowest of the Low: Neuroimaging Responses to Extreme Out-Groups, Harris and Fiske, 2006, Psychological Science (free abstract)