"Read Montague" is not some command your prelapsarian political science professor gives you. It's the name of a computational neuroscientist who studies decision-making. He's the latest to release research showing something unusual going on in the brains of people who affiliate with a particular ideology.

Specifically, he reports that Democrats and Republicans have different reactions when they're shown disgusting pictures, so much so that the reactions themselves can predict, reliably, whether the person looking at the image identifies voluntarily as liberal or conservative.

He recruited a random sample of adults, who then filled out political questionnaires. Then, each subject climbed into a special functional magnetic resonance imaging machine. The team then showed each participant a series of pictures, some of them disturbing, like a mutilated carcass of an animal. The fMRI recorded blood flow patterns across each person's brain as it processed the images. "The brain-imaging results were fed into an algorithm that compared the whole-brain responses of liberals and conservatives looking at disgusting images and versus neutral ones," according to New Scientist.

The computer was able to predict, to an accuracy of about 98 percent, whether each brain recording matched to a person who scored as a liberal or as a conservative, and even to degrees of ideological difference within those broad categories.

Conservatives, in particular, seemed to react more violently to universally repulsive images, like maggot infestations.

Why?

Are conservatives' brains different than liberal brains? Montague says he was drawn to the topic when he read that political ideology seemed to have a heritability quotient that was significant, meaning that, in some sense yet to be discovered, how you think about politics is influenced by your genes. (Love those twin studies!)

This study suggests that the way we decide to engage politically and the type of information we subject ourselves to changes the way our brain processes external stimuli. Over time, the way we talk about politics influences us subconsciously.

Montague, in his press release, says he was surprised by how strong the differences were. "Remarkably, we found that the brain's response to a single disgusting image was enough to predict an individual’s political ideology."

Extrapolating a bit here, we can begin to understand why persuading voters to change their affiliations, or to change their minds about an issue that has partisan resonance, like, say, ObamaCare, is so hard. To change minds, you've got to change brains at deep levels that are not available to our conscious decision-making.

Like any good upstanding American researcher, Montague thinks that bipartisanship is a good thing. By implication, partisanship is a bad thing. If voters begin to understand that their decisions are reflexive even when they don't seem reflexive, then maybe they'll be able to force their own minds to open up more, to actively interrupt the automatic processes that tell us whether something is good or bad.

We know that Americans seem to be sorting themselves into like-minded neighborhoods. Conventional wisdom has us moving to places that fit our political predispositions. The actual data tracks the view that people aren't moving because of politics. They just change political parties when political parties adopt ideologies that track more closely with their own. And since the mid 1990s, the GOP, in particular, has moved far to the right. (This is why conservatives don't like to identify as Republican but will certainly vote for Republicans 90 percent of the time.)

The data suggests that as the political parties became more strident and clear in taking their own positions, people began to associate more indelibly with them.