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Disgust and a New Political Neuropsychology

Do politicians disgust you? If you are shown a photo of a politician you despise, chances are you will suddenly feel as though you were gulping down your least favorite food. But beyond the personality flaws of our politicians, a tendency toward being easily disgusted can affect a person’s view on political issues. In studies where participants are shown sickening images, such as a person eating worms, conservatives report higher levels of disgust than do liberals (Smith et. al, 2011). The emotion of disgust encourages humans to avoid infection; images of disfigurement and infection temporarily increase behavioral avoidance of novelty (Neuberg, Kenrick, & Schaller 2011). For a long time, the prevailing theory was that we form opinions and make decisions based on formal reasoning (Kohlberg, 1975). The theory of social intuitionism proposes that we use reasoning to justify our opinions ad hoc. It is possible that formal reasoning has more influence in other parts of human thinking, but the emphasis on irrationality of social intuitionist theory seems well suited for political thought.


Along with a greater propensity toward disgust, conservatives tend to see purity as a moral characteristic while liberals do not. This has the mundane consequence that liberals have messier bedrooms. More exciting is that conservatives are more likely to view premarital sex as immoral because it conflicts with the notion of purity. Disgust, as a reaction to impurity, is one of the most powerful emotions. According to the theory of social intuitionism, disgust for homosexuality would drive conservative opposition to gay marriage. In the Smith (2011) study, the correlation between disgust sensitivity and conservative social values is strong, but there is little or no correlation between disgust sensitivity and political attitudes on tax policy and foreign aid. Liberals have little use for purity and do not generally oppose gay marriage. Anatomical MRI has recently corroborated the psychological evidence supporting social intuitionist theory.


The insula cortex is frequently active when a person experiences disgust, and sure enough at least one study found that the insula is larger in conservatives (Kanai et. al 2011). The insula is involved in many cognitive processes, and imaging research does not prove that a larger insula in conservatives is responsible for the power of disgust over cognition. The right amygdala, a region of the brain well known to be involved in fear processing, is also larger in conservatives. Liberals have a larger cingulate cortex, and the authors (Kanai et. al 2011) infer that liberals have a greater capacity for “increased sensitivity to cues for altering a habitual response pattern.” The authors talk around it, but the implication of the research is that conservatives are driven more by fear and disgust than liberals. 

 The Insular Cortex


The interpretation of fMRI data deserves its own blog post, but for an excellent primer on the limitations of fMRI, I recommend Logothetis’s 2008 review in Nature.  Even if the currently favored hypotheses are disproven, political neuroscience will continue to dredge up uncomfortable truths for all political groups. How will scientists be able to discuss these issues dispassionately when they will undoubtedly be subject to increased scrutiny and attacks from angry citizens who are proud of their political beliefs? Scientists feel comfortable speculating on data that has no political relevance, but simultaneously feel the need to self-sensor when publishing on the neuroscience of politics. Scientists will be accused of fitting their personal political agenda to the data, and these accusations may have merit in some cases. But how can we discuss this research honestly without drawing the ire of an interested public? This is not a dilemma with an easy way out.


(Political neuropsychology can also help us explain the causes of political events from the past. In the past ten years, gay marriage has gone from being wildly unpopular to the law of the land in several states. But how can that be? A study from 2006 (Schiappa, Gregg, and Hewes) points to popular sitcom “Will and Grace.” The popular television show exposed lovable gay characters to viewers who may never have met a gay person in their own lives. Now it is not noteworthy at all for there to be a gay character on television. With likeable gay characters in every living room, suddenly gay marriage seems less disgusting to most Americans.)


Political consultants and spin-doctors create the advertisements to help candidates win office, but rarely are those ads based on solid research. But it is not hard to imagine moneyed interests organizing ad campaigns based on knowledge gained from social intuitionism theory. Proponents of gay marriage could run ads that further lessen the disgust for homosexuality. Conservatives frequently accuse Hollywood of promoting the homosexual agenda, and it’s true that “Milk” and “Brokeback Mountain” played on our emotions, perhaps overriding any lingering disgust. With few barriers to political spending, the American viewer will become a participant in a test of social intuitionist theory. In a sense, the viewer always has been an unwitting participant, because there is no Institutional Review Board (IRB) at the Federal Communications Commission. It is a great irony that a psychology experiment on a few dozen college students that weakened disgust would certainly be shunned by the IRB, but the same experiment could be broadcast to millions of homes for the right price.


If you want to know more about social intuitionism, I recommend Jonathan Haidt’s book, “The Righteous Mind:Why Good People are Divided by Politics and Religion.” Emory has its own political guru in Drew Westen:  The Political Brain: The Role of Emotion in Deciding the Fate of the Nation.” Finally, if you really want to understand American political psychology, watch Dr. Strangelove: 


  Kevin Fomalont 

Kevin Fomalont is an Emory Neuroscience graduate student in the Graduate Certificate Program in Brain, Mind, and Culture. The Center for Brain, Mind, and Culture fosters interdisciplinary discussion from multiple explanatory perspectives at Emory University. Their list of scheduled events for the semester is located on their website:  


Want to cite this post?

Fomalont, K. (2012). Disgust and a New Political Neuropsychology. The Neuroethics Blog. Retrieved on
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