Our emotions are strongly tied to our morals. We're more likely to think something is wrong if it repulses us, even if we can't describe exactly why or how it is wrong. For example, most people would disapprove of consensual adult incest between siblings, but few would be able to articulate exactly why it is 'wrong.' This is very different from moral beliefs deduced from reasoning. These moral intuitions, which are highly motivated by emotional response or learned associations, are quick and require little supporting evidence in the person's mind.
Since emotions affect our morals, it easily follows that they affect our political beliefs. Two studies from Cornell University explored this relationship between disgust and politics and found a very interesting result: conservatives, particularly those that are conservative with respect to social issues like abortion and gay marriage, are more easily disgusted.
Why do humans feel disgust in the first place? Many scientists believe it evolved as a way of avoiding disease or unhealthy things - rotting fruit, feces and urine, wounds oozing puss, etc. Our bodies naturally react with revulsion to things that carry disease, parasites, or risks to our health. Disgust is ubiquitous in people. All people show a very specific face when feeling disgust, and can readily identify that same face in others: a raised the upper lip and wrinkle the nose, for example. Feeling disgust and seeing it in others is hard-wired into our brains: people with Huntington's, a neurodegenerative disorder, cannot tell when others are disgusted and do not show disgust when presented with something revolting.
So why do some of us feel disgust towards things that are not imminent health threats? No one's really sure. The assumption is that somehow our morals got tied into a much more primitive system (that of disgust). It's a phenomenon called preadaptation, where something that evolves for one purpose is later used for another. Think of feathers, for example. Many scientists believe that feathers evolved for displays or disguise, and only later were utilized in flight.
Issues like gay marriage and abortion are heavily rooted in moral beliefs. So researchers from Cornell University wanted to know how disgust related to those political views. What they found was that conservatives, in general, are more easily grossed out and repulsed by things.
To understand the link between disgust and politics, Cornell researchers performed a few experiments. First things first, they wanted to show how the human face responds when disgusted. In the first study, published in Science, they gave participants foul drinks and had them view photographs of uncleanliness and contamination-related disgust stimuli, including feces, injuries, insects, etc. In both cases, participants responded with the clear, well-known face of disgust (a look you probably had when you saw the image at the top of this post). They then had the participants play a game where they were treated unfairly to see if a moral situation provoked that disgusted facial expression. Sure enough, the same snarled lip expression occurred (Left). They even asked the participants afterward about their feelings, and offers that were rated as more disgusting were significantly associated with more activation of the levator labii region.
But the researcher's didn't stop there. In another paper, published in the journal Emotion, the researchers further probed the relationship between disgust and morality. This time they had participants take the Disgust Sensitivity Scale (DSS), a psychological measure which quantifies a person's sensitivity to a variety of forms of disgust from core disgust (feces, etc) to blood and gore, and even unusual sexual practices (like incest). They then compared this to the participants self-reported religious affiliation and political views. High sensitivity to disgust significantly predicted conservative views on topics like abortion and gay marriage, a connection not explained by religious affiliation. The same was not true for other non-disgust related issues like affirmative action, labor unions or gun control.
Even still, the researchers weren't done. Self reported data has its own flaws and faults - mostly, people lie or don't always represent themselves as they really are. So to test the connection between disgust and morality implicitly, the researchers designed a unique experiment (PDF). They had participants look at a scene. In it, a director appears to be encouraging two men or a man and a woman to kiss in public. They then took measures of disgust sensitivity. When asked if there was anything wrong with two men or straight couple kissing, the participants mostly said no. But when asked if the director intentionally encouraged the couples to kiss, those who were more sensitive to disgust were more likely to view the director's action as intentional when encouraging the gay couple - but NOT when encouraging the straight couple. This implicitly showed a bias against gay kissing even when the participants self reported as non-biased - a bias tied to their sensitivity to disgust in general.
In short, conservatives, especially those who are conservative on disgust-driven moral initiatives like gay marriage or abortion, are more easily disgusted. Since disgust is, at least in part, rooted to genetics, its possible that a part of our political views are literally determined in our genes.
The question is, how tied to our instinctive disgust system is this moral disgust? After all, it is the instinctive disgust which is in our genetics. A review of the article published in Science makes this note:
Unfairness and other moral violations may directly affect the disgust output system, after processing by some other evaluation system, or these violations might simply activate the verbal label "disgust," which would then activate the disgust output system. The outcome of either route would include the facial expression of disgust.
This means that while the data is convincing in tying disgust to political views, it doesn't say whether this disgust is innate, like repugnance of dirty toilets, or learned through our environments and merely hitchhiking on the disgust system. It's possible that the disgust shown and felt on moral issues comes from the word disgust being used to describe it, not from an inner sense of revulsion or morality.
But if it is rooted deeper, it's entirely possible that our genes help determine our political views, even before we understand what a liberal or a conservative is. Even without cultural influences, it is likely that those who are easily grossed out or squeamish are more likely to be conservative on moral issues.
Which makes sense, too, when we look at current moral stances. Many liberal viewpoints stress a logical understanding of the issue and a general "if it doesn't hurt another person, it's OK" attitude towards behaviors. Conservatives, on the other hand, press upon people to follow their instincts. Leon Kass, a noted conservative bioethicist, has argued for what he calls "the wisdom of repugnance" - that our natural aversion to something is evidence of its evil or wrongness. This different approach to defining 'right' and 'wrong' is at the center of disagreements between the two parties.
I think research like this fascinating because it probes deep into our understanding of why we feel the way we do. So often we spend so much time focusing on why one animal does this or why another does that we forget that we, too, are animals. We neglect that, as complex as our intellect may be in comparison, we still are shaped by our genes and our environments. And I think understanding is key, especially when it comes to politics. If we cannot understand why people feel how they do, we can never truly decide what is right or wrong for our society and ourselves.
1.Chapman, H., Kim, D., Susskind, J., & Anderson, A. (2009). In Bad Taste: Evidence for the Oral Origins of Moral Disgust Science, 323 (5918), 1222-1226 DOI: 10.1126/science.1165565
2.Inbar, Y., Pizarro, D., & Bloom, P. (2008). Conservatives are more easily disgusted than liberals Cognition & Emotion, 23 (4), 714-725 DOI: 10.1080/02699930802110007
3. Inbar, Y., Pizarro, D., Knobe, J., & Bloom, P. (2009). Disgust sensitivity predicts intuitive disapproval of gays. Emotion, 9 (3), 435-439 DOI: 10.1037/a0015960
4.Rozin, P., Haidt, J., & Fincher, K. (2009). PSYCHOLOGY: From Oral to Moral Science, 323 (5918), 1179-1180 DOI: 10.1126/science.1170492