Conservatives showed much stronger skin responses to negative images, compared with the positive ones. Liberals showed the opposite. And when the scientists turned to studying eye gaze or “attentional” patterns, they found that conservatives looked much more quickly at negative or threatening images, and [then] spent more time fixating on them.

Mooney concludes that this “new research suggests [that] conservatism is largely a defensive ideology — and therefore, much more appealing to people who go through life sensitive and highly attuned to aversive or threatening aspects of their environments.”

But those cognitive biases are only part of the story of how a political movement in the wealthiest, most secure nation in the world have come to view their surroundings with such dread. The other half of the equation is a conservative media establishment that feeds members of the movement an almost endless stream of truly terrifying scenarios.

The phenomenon of media “siloing” is pretty well understood – in an era when dozens of media sources are a click away, people have a tendency to consume more of those that conform to their respective worldviews. But there is some evidence that this phenomenon is more pronounced on the right – conservative intellectuals have had a long-running debate about the significance of “epistemic closure” within their movement.

So conservatives appear to be more likely to be hard-wired to be highly sensitive to perceived threats, and their chosen media offers them plenty. But that’s not the whole story because of one additional factor. Since 9/11, and especially since the election of President Barack Obama, one of the most significant trends in America’s political discourse is the “mainstreaming” of what were previously considered to be fringe views on the right. Theories that were once relegated to the militia movement can now be heard on the lips of elected officials and television personalities like Glenn Beck.

Consider, then, what it must be like to be a true-blue Rush Limbaugh fan, or someone who thinks Michele Bachmann is a serious lawmaker with a grasp of the issues – put yourself into that person’s shoes for a moment, and consider what a nightmarish landscape the world around them must represent:

The White House has been usurped by a Kenyan socialist named Barry Soetero, who hatched an elaborate plot to pass himself off as a citizen of the United States – a plot the media refuse to even investigate. This president doesn’t just claim the right to assassinate suspected terrorists who are beyond the reach of law enforcement – he may be planning on rounding up his ideological opponents and putting them into concentration camps if he is reelected. He may have murdered a blogger who was critical of his administration, but authorities refuse to investigate. At the very least, he is plotting on disarming the American public after the election, in accordance with a secret deal cut with the UN and possibly with the assistance of foreign troops.

Again, these ideas are not relegated to the fringe of forwarded emails. Glenn Beck talked about FEMA camps on Fox News (he later debunked them, which only fueled charges of a media coverup); dozens of Republican elected officials have at least hinted that they are birthers, while an erstwhile front-runner for the GOP nomination has repeatedly claimed that Obama is not eligible to be president. The head of the NRA, and the GOP’s presidential nominee have both claimed Obama is plotting to take Americans’ guns.

In reality, Americans are safer and more secure today than at any point in human history. But inhabitants of the world of the hard-right are surrounded by danger – from mobs of thugs at home to a variety of powerful and deadly enemies abroad.

For the true believers, Latin American immigration isn’t a phenomenon to be managed, but a grave existential threat. A plot to “take back” large swaths of the Southwest is a theory that has aired not only on obscure right-wing blogs, but on Fox and CNN. On CNN, Lou Dobbs claimed immigrants were spreading leprosy; Rick Perry, Rep. Louie Gohmert and other “mainstream” voices on the right (that is, people with platforms) agree that Hezbollah and Hamas “are using Mexico as a way to penetrate into the southern part of the United States,” possibly with the aid of “terror babies” carried in pregnant women’s wombs.

In the real world, the rate of violent crime in the US is at the lowest point since 1968 – in fact, it is somewhat of a mystery that the violent crime rate has continued to decline even in the midst of the Great Recession. It’s also true that 84 percent of white murder victims are killed by other whites. But if you read the Drudge Report, or check in at Fox, on any given day you will see extensive coverage of any incident in which a black person harms a white person. These fit in with the narrative – advanced by people like Glenn Beck and long-touted by Ron Paul – that we stand on the brink of a race war, led by the New Black Panthers (just consider how frightening it would be if there were more than a dozen New Black Panthers, or if they did more than say stupid things). Marauding “flash-mobs” of black teens – a near-obsession at many conservative outlets these days — are simply a harbinger of things to come.

Continue, for a moment, to stroll in the shoes of a true believer on the right. Imagine how frightening it would be to believe Frank Gaffney, a former Assistant Secretary of Defense in the Reagan administration and leading neoconservative voice, when he claims the Muslim Brotherhood has infiltrated the highest levels of the US government, or Newt Gingrich, when he says that “sharia law” (there isn’t such a thing in the way conservatives portray it – as a discrete canon of laws) poses a grave threat to our way of life.

Imagine believing that the Democrats’ business-friendly insurance reforms included panels of bureaucrats who would decide when to let you die, as Sarah Palin infamously suggested. Or that virtually the entire field of climatology is perpetrating a “hoax,” as senator James Inhofe claims, in order to undermine capitalism and impose a one-world government. Imagine seeing energy-efficient light bulbs as part of an international plot to, again, undermine capitalism, as Michele Bachmann believes. Imagine thinking that the public school system “indoctrinates” young children into the “gay lifestyle,” as influential members of the religious right – James Dobson, Bryan Fischer, Anita Bryant – have claimed for years. Imagine believing our electoral system is tarnished by massive voter fraud or that union thugs are running amok or that the Department of Homeland Security is making a list of people who advocate for “limited government.” Imagine if there really were a War on Christmas!

These dark narratives come in addition to more run-of-the-mill fear-mongering about the Iranian “threat,” or nonsense about how “entitlements” are leading our economy to look like Greece’s. Those of us in the “reality-based community” may look at these specters haunting the right with exasperation or amusement, but just consider for a moment how bleak the world looks to those who buy into these ideas.

Perhaps the most frightening part of all of this for the true believers is that even though these things aren’t just fringe ideas circulating in forwarded emails – they’re discussed by influential politicians and on leading cable news outlets – the bulk of the media and most elected officials refuse to investigate what’s happening to this country.

That one ideological camp is so consumed with fear also has a lot to do with why conservatives and liberals share so little common ground. Progressives tend to greet these narratives with facts and reason, but as Chris Mooney notes, when your amygdala is activated, it takes over and utterly dominates the brain structures dedicated to reason. Then the “fight-or-flight” response takes precedence over critical thinking.