Maggot infestations, rotting carcasses, unidentifiable gunk in the kitchen sink - how much your brain responds to disgusting images could predict whether you are liberal or conservative. 
 
 In a study to be published in an upcoming issue of Current Biology, an international team of scientists led by Virginia Tech reports that the strength of a person's reaction to repulsive images can forecast their political ideology. 
 
 "Disgusting images generate neural responses that are highly predictive of political orientation even when those neural responses don't correspond with an individual's conscious reaction to the images," said Read Montague, a Virginia Tech Carilion Research Institute professor who led the study. "Remarkably, we found that the brain's response to a single disgusting image was enough to predict an individual's political ideology." 
 
 In a brain scanner, participants were shown disgusting images, such as dirty toilets or mutilated carcasses, mixed with neutral and pleasant images, such as landscapes and babies. 
 
 Afterward, the subjects took a standard political ideology inventory, answering questions about how often they discuss politics and whether they agreed or disagreed with hot-button topics such as school prayer and gay marriage. 
 
 Using functional magnetic resonance imaging, scientists from the Virginia Tech Carilion Research Institute - in collaboration with researchers from University College London, Rice University, the University of Nebraska at Lincoln, and Yale University - recorded brain activity of the subjects responding to the images. 
 
 Responses to disgusting images could predict, with 95 percent to 98 percent accuracy, how a person would answer questions on the political survey. 
 
 The results suggest political ideologies are mapped onto established neural responses that may have served to protect our ancestors against environmental threats, Montague said. Those neural responses could be passed down family lines -- it's likely that disgust reactions are inherited. 
 
 "We pursued this research because previous work in a twin registry showed that political ideology -- literally the degree to which someone is liberal or conservative -- was highly heritable, almost as heritable as height," said Montague, who directs the Computational Psychiatry Unit at the Virginia Tech Carilion Research Institute. 
 
 Conservatives tend to have more magnified responses to disgusting images, but scientists don't know exactly why, Montague said. 
 
 The responses could be a callback to the deep, adverse reactions primitive ancestors needed to avoid contamination and disease. To prevent unsavory consequences, they had to learn to separate the canteen from the latrine. 
 
 Montague points out that we're not necessarily hardwired to respond on instinct alone. He uses height as an analogy. 
 
 "Genetics predetermines height - but not fully," Montague said. "Nutrition, sleep, and starvation can all change someone's ultimate height. But tall people's children tend to be tall, and that's a kind of starting point. If we can begin to understand that some automatic reactions to political issues may be simply that - reactions - then we might take the temperature down a bit in the current boiler of political discourse." 
 
 People are unique among animals in their degree of cognitive control. Montague calls it a behavioral superpower. 
 
 "People can deny their biological instincts for an idea - think of hunger strikes for political reasons," Montague said. "That requires a high degree of cognitive control, and that's the point." 
 
 The takeaway message for Election Day? 
 
 "Think, don't just react," Montague said. "But no one needs neuroscience to know that's a good idea." 
 
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 The Wellcome Trust Principal Research Fellowship, the Gatsby Charitable Trust, the National Science Foundation, and the Kane Family Foundation supported the research. 
 
 Written by Ashley WennersHerron 

 One of the most fascinating things about political ideology is that it's likely much more genetic than most people realize. Of course "nurture" matters, but there's strong evidence that people are also born with certain features and personality traits that predispose them toward leaning liberal, conservative, or libertarian. A new study suggests that unconscious reactions to a single "disgusting image" can reliably predict whether someone identifies as liberal or conservative. 
 
 The study, published in the most recent issue of Current Biology, relied on brain scans of people shown a series of gross, pleasant, and neutral images. Researcher P. Read Montague, a Virginia Tech professor and head of the school's Human Neuroimaging Lab, said he was inspired by research showing political affiliation is highly heritable and how one identifies politically has deep connections to biology, especially the way our bodies respond to threats of "contamination" or violence. 
 
 The brain scans revealed that, indeed, the way one's neurons fired in response to gross-out imagery was a pretty damn good indication of whether one identified as liberal or conservative. While responses to the pleasant and neutral images were predictive of nothing, responses to an image of a mutilated animal body were split neatly down political lines. 
 
 "A single disgusting image was sufficient to predict each subject's political orientation," said Montague. "I haven't seen such clean predictive results in any other functional imaging experiments in our lab or others." The results "suggest that important foundational parts of political attitudes ride on top of preestablished neural responses," he said. 
 
 Self-reported responses to the imagery were not an accurate predictor of political persuasion. 
 
 "These results provide strong support for the idea that fundamental neural processing differences that emerge under the challenge of emotionally evocative stimuli may serve to structure political beliefs in ways formerly unappreciated," the researchers concluded. 
 
 Ronald Bailey has written here previously about research showing political conservatives are more easily grossed out. Other research has shown that those with low sensitivity to disgust tend to be liberals or libertarians. 
 
 h/t Mark Sletten 

 The way a person's brain responds to a single disgusting image is enough to reliably predict whether he or she identifies politically as liberal or conservative. As we approach Election Day, the researchers say that the findings reported in the Cell Press journal Current Biology on October 30 come as a reminder of something we all know but probably don't always do: "Think, don't just react." 
 
 P. Read Montague of Virginia Tech says he was initially inspired by evidence showing that an individual's political affiliation is almost as heritable as height. Montague and his colleagues also recognized that those political ideologies summarize many aspects of life--attitudes associated with sex, family, education, and personal autonomy, for instance--and have deep connections to the way our bodies respond to threats of contamination or violence. 
 
 To find out just how fundamental those connections are, Montague and his colleagues asked whether functional magnetic resonance images (fMRI) of the brain taken as people passively looked at a series of disgusting, pleasant, and neutral images was enough to give away their political leanings, as measured on a standardized test. (The Wilson Patterson inventory produces a score from 0 to 1, from extremely liberal to extremely conservative.) 
 
 The researchers applied a machine-learning method to all of those pictures together with the test scores in search of a predictable relationship between the two. And, indeed, they found it. Disgusting images, and the mutilated body of an animal especially, generated neural responses that were highly predictive of political orientation. That was true even though the neural predictors didn't necessarily agree with participants' conscious rating of those disturbing pictures. 
 
 It's not clear from the study exactly how or why liberal versus conservative brains differ from each other, Montague explains, only that they do. In fact, the researchers were especially surprised by the strength of the response. 
 
 "A single disgusting image was sufficient to predict each subject's political orientation," he says. "I haven't seen such clean predictive results in any other functional imaging experiments in our lab or others." 
 
 Perhaps the new findings can help us find a way to a less-polarized political future. People really do differ from one another in fundamental ways, but we also have the unique ability to make up our own minds and to change them. 
 
 "The results do not provide a simple bromide, but they do suggest that important foundational parts of political attitudes ride on top of preestablished neural responses that may have served to defend our forebears against environmental threats," Montague says. "In the same sense that height is highly genetically specified, it's also true that it's not predetermined by genetics; nutrition, sleep, starvation, dramatic physical injury, and so on can serve to change one's ultimate height. However, tall people have tall children, and this is a kind of starting point." 
 
 "In the same vein, if we can begin to see that some 'knee-jerk' reactions to political issues may be simply that--reactions--then we might take the temperature down a bit in the current boiler of political discourse." 
 
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 Current Biology, Ahn et al.: "Nonpolitical images evoke neural predictors of political ideology."
– What can pictures of maggot infestations, mutilated animals, dirty toilets, and rotting corpses tell you about a person's political affiliation? A lot, apparently. Researchers led by Virginia Tech scanned people's brains as the subjects looked at disgusting images, and they found that the strength of the brain responses could predict—with up to 98% accuracy—whether a person was liberal or conservative ... even when those responses don't correspond to how the subject consciously reacted to the image. Researchers found that conservatives had more magnified responses to the repulsive photos. As they write in Cell Biology, the brain's reaction to a single gross image was "remarkably ... sufficient to make accurate predictions about an individual subject’s political ideology." Why? As the lead researcher explains, previous research has found political affiliation to be "almost as heritable as height," and disgust reactions are also likely inherited. As a press release puts it, "the responses could be a callback to the deep, adverse reactions primitive ancestors needed to avoid contamination and disease. To prevent unsavory consequences, they had to learn to separate the canteen from the latrine." As such, "some 'knee-jerk' reactions to political issues may be simply that—reactions," the lead researcher says. As Reason notes, previous studies have uncovered similar findings: One found that conservatives get disgusted more easily, while another found that those who aren't very easily disgusted tend to be liberal. (Your preference for Dunkin' Donuts or Starbucks might also say something about your political leanings.)