Now a person need not speak to reveal his or her political views. Electrical brain responses to certain images can be used to predict the political leanings of subjects shown disgusting images. A team of U.S. and British researchers was successful at identifying liberals and conservatives by looking for predictive patterns in their brains while they were shown disgusting images of mutilated animals or contaminated food.

“I haven’t seen such clean predictive results in any other functional imaging experiments,” said team leader Read Montague, a computational psychiatrist at Virginia Tech and University College London.

It was not the conscious reactions of the study participants to the images but their subconscious neural responses that betrayed their political affiliations. The researchers measured differential blood oxygen levels in the brain using functional magnetic resonance imaging, or fMRI. The patients brains were scanned while they rested and then again while they viewed a variety of images.

“Remarkably, brain responses to a single disgusting stimulus were sufficient to make accurate predictions about an individual subject’s political ideology,” the researchers wrote in their report published on Thursday in the journal Current Biology.

“People tend to think that their political views are purely rational,” the authors wrote. However, these findings suggest that politics may be directed by neural hardwiring.

The team contends that cognition, or thought, and emotion are interconnected and that the idea that they can somehow be separated is “becoming obsolete.” They state that emotional processes are coupled to complex human beliefs.

The study involved fMRI scanning of 83 volunteers shown 80 randomly ordered images of pleasant, neutral, threatening, or disgusting objects. Political views were assessed by computerized questionnaire that asked about topics such as party affiliation, immigration, and gun control. Only the disgusting images evoked a brain scan pattern that was predictive of self-reported political leanings.

The authors also emphasized that political views are not necessarily set in stone. “If we can 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 boiler of political discourse,” they wrote.