When researchers showed disgusting images of snakes, roaches, garbage, vomit, mutilated bodies and open wounds to participants in a Virginia Tech study, they found significant differences between the way liberals and conservatives reacted, on a neural level.
Though the volunteers didn't report feeling any more or less grossed out by the images, brain scans told a different story. The more strongly a person's brain reacted to seeing disgusting images, the more likely they were to hold conservative views.
The same discrepancy did not exist in their responses to positive images.
The authors point out in the paper, published in the journal Current Biology, that this is the first brain study to find multiple points of differentiation in activity when comparing the emotional processing of images in liberals versus conservatives. Several parts of the brain lit up in conservatives, while others were activated in liberals.
An illustration summarizing fMRI scans of the brain viewing a disgusting image. Even a single presentation of a disgusting stimulus is sufficient to make accurate predictions of individual's political orientation. Red/yellow spots predict conservative orientation and blue/green spots predict liberal orientation.
P. Read Montague and his coauthors wrote in the study that their results "invite the provocative claim that neural responses to nonpolitical stimuli (like contaminated food or physical threats) should be highly predictive of abstract political opinions (like attitudes toward gun control and abortion)."
Indeed, watching the brain's reaction to a single disgusting image was sufficient to guess each subject's political orientation. Montague said in the press release, "I haven't seen such clean predictive results in any other functional imaging experiments in our lab or others."
The researchers used functional Magnetic Resonance Imaging (fMRI) to track how the brains of 83 volunteers reacted to viewing emotionally charged but politically neutral images. The volunteers were then asked to rate how disgusting, threatening, or pleasant they thought each image was, and then answer a standard questionnaire about political ideology.
The study did not determine exactly how or why liberal brains differ from conservative ones, only that the two types of brains lit up in two different patterns when viewing the same images.
Continued here:
How you react to this photo reveals your political beliefs