I happened upon a TV ad one day last week for medical equipment that I have always found particularly disturbing. I don't need to go into a lot of detail, because I think we all have something like this that makes us a little queasy and causes us to scrunch up our faces and turn down the corners of our mouths--the universal face for disgust.
Disgust is a marked feeling of revulsion or profound disapproval aroused by something unpleasant, distasteful, or offensive. The things that consistently arouse disgust are also things that make us sick, such as excrement and corpses, which are sources of life-threatening bacteria and viruses. So it is believed that the disgust response helps us avoid contaminated items that could give us a disease and, in evolutionary terms, reduce our chances of survival and reproduction. Because of its role in survival as well as the particularly old region of the brain (anterior insula) that is most active when people experience disgust, it is often described as one of the original emotions and thought of as a building block for other emotions.
So what's the political connection? Evidence suggests that harm avoidance and the need for fairness underlie people's moral judgments in a number of cultures. While liberals rely primarily on these two values, conservatives also rely on desires for group loyalty, authoritative structure, and, most importantly here, purity. Following this logic, Kevin and other researchers became interested in the potential for a relation between disgust and political orientations. They speculated that conservatives are more disgust sensitive than liberals as a result of their concern with purity-related norms and that this difference would manifest itself on issues that some may associate with sexual purity (e.g., homosexual sex and, therefore, gay rights).
Sure enough, Kevin and his co-authors found that conservatives are more easily disgusted than liberals. Not only did they find an association in self-reported measures of disgust sensitivity and political ideology asked on questionnaires, they also found it in involuntary physiological responses (i.e., changes in skin conductance levels) to a series of pictures, some of which aroused disgust. I am going to tell you about those disgusting pictures next, so if you are really squeamish (or are a raging conservative?), you should consider jumping ahead to the next paragraph. They were: a man eating a mouthful of writhing worms, a horribly emaciated but living person, and human excrement floating in a toilet. Not so bad...?
I believe Kevin and I share an important and vastly underappreciated perspective on political behavior: some political attitudes are biologically influenced. People do not fully control their responses to disgust, just like they do not fully control their responses to evolutionary predispositions (remember my two posts on height and leadership: 1 and 2?). A broader understanding of this may take some of the nastiness out of our current political rhetoric as people comprehend how their political opponents can sometimes come to what seem like incomprehensible positions.
What's your disgust sensitivity? Want to compare yourself to liberals and conservatives? You can complete the Disgust Scale at YourMorals.org (register by answering a handful of typical survey questions then select the "Disgust Scale").
This is the disgust sensitivity survey upon which part of Kevin and his co-authors' research is based. They focused on the "core" and "contamination" disgust scores. Core disgust relates to protecting the mouth from unhygienic or inappropriate things (e.g., spoiled food or body excretions). Contamination disgust relates to protecting the entire body, not just the mouth, from harmful things (e.g., dirty or sleazy people).
To give you some basis of comparison for your scores, the bar graph in this post shows the average scores of more than 35,000 respondents who identified themselves as liberal or conservative as well as male or female. It also shows the clear, expected pattern of conservatives (black bars) rating higher on disgust sensitivity than liberals (grey bars) and the stereotypical pattern of women (pink bars) rating higher than men (blue bars). (For a really interesting finding about differences in disgust sensitivity between men and women, search Kevin's article for "folk wisdom" and read the associated paragraph.) You can even see my scores (green bars) if you're interested.
By the way, green was also the color of my face after watching that TV ad for medical equipment last week.
Take the survey and post a comment about if your political ideology fits with your disgust sensitivity.
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For more information: Smith, Kevin B., Douglas Oxley, Matthew V. Hibbing, John R. Alford, and John R. Hibbing. 2011. "Disgust Sensitivity and the Neurophysiology of Left-Right Political Orientations." PLoS ONE 6(10): e25552.