Read Montague recently appeared on a new PBS series, The Brain with David Eagleman, in an episode exploring neurological research on how humans make decisions. Montague spoke about his finding that biology influences political ideology, which was published in Current Biology.

Study participants were placed in a brain scanner and 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.

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.

“I show you a disgusting image, I know how you're going to vote in 2016,” Montague said in the show.

Montague is the director of both the Computational Psychiatry Unit and the Human Neuroimaging Laboratory at the Virginia Tech Carilion Research Institute.

Read more about Montague’s research here.

Watch the episode of The Brain with David Eagleman here.