Barack Hussein Obama has 18 letters in his name. That’s 6+6+6, or 666. Get it?

Substantial numbers of Americans believe Obama is the Antichrist. One survey in New Jersey found that as many as one in five people believe this theory. Similar numbers of people believe other crazy theories, including that Obama is a Muslim, a foreigner, and a socialist.

The traditional way to disabuse people of false beliefs is to provide them with accurate information. Here’s Obama’s birth certificate, for example. Hundreds of news Web sites have published evidence that Obama was born in the United States, but disbelief persists. Why is this?

When we confront crazy beliefs that are widely held, we usually blame propaganda. The Germans believed the lies Hitler told them (we tell ourselves). Those who do not believe that Obama’s birth certificate is valid must have been misled by ideological commentators. This theory reflects a profound naiveté about how our minds work, and it externalizes blame that is better turned inward.

In recent years, dozens of psychological studies have shown that we shape incoming information as much as it shapes us. We sift and sort, choosing what we like and discarding what we don’t. Much of this happens unconsciously in what I call the hidden brain. We see the effects of these mental gymnastics all the time: Few people change their minds on hot-button issues, even when new information is provided to them. Political commentators generate lots of heat, but when was the last time you heard about a liberal who was persuaded by Rush Limbaugh? Or a conservative who switched parties after watching a Michael Moore movie? The partisan divide in the country has barely budged for over a decade—hardly what you’d expect if the hyper-partisan information we see all around us was having much effect.

Social psychologist Tom Pyszczynski at the University of Colorado, with co-authors Carl Henthorn, Matt Motyl and Kristel Gerow, recently published an interesting study in the Journal of Experimental Social Psychology. Pyszczynski told volunteers they were participating in a creative writing exercise, and he divided them at random into two groups. He asked one group to write a short essay about a student named Tyrone Walker, and another to write an essay about Brad Walker. This turns out to be an effective technique to activate (or “prime”) people’s racial attitudes without their awareness: Tyrone Walker is a typically black name and Brad Walker is a typically white name. (The essays revealed as much—the Tyrone essays typically were about a black student, and the Brad essays were about a white student. Earlier experiments have found that the technique produces clearly measurable differences on various skills affected by racial attitudes.)

The volunteers then read an editorial about Obama. The ideas in it were drawn from various Web sites:

The Anti-Christ will be a man in his forties, he will be of Muslim descent, people will flock to him and he will promise false hope and world peace, he will not have any male descendants to pass on his name, he will be an unknown man that rises to power. … Obama … only has daughters for children, he is a man in his forties that comes from Muslim descent, he was an unknown man who has risen to power, and he promises world peace.

Volunteers given the “white prime” were less likely to buy the Antichrist editorial than those given the “black prime.” Think about that for a second: Merely being asked to write an essay about Tyrone Walker rather than Brad Walker caused people to believe the Antichrist claim. It was the stuff happening inside people’s heads—not the information in the fake editorial—that was decisive here. The Antichrist editorial was the same for all volunteers, but the hospitability for that information in people’s heads changed depending on which prime they were given.

I’ll talk in another piece about why racial priming should make any difference in people’s willingness to believe in a theory that ostensibly has nothing to do with race, but the point here is that people’s mental predispositions, not the Antichrist claim itself, explained why some found the theory persuasive while others did not.

The idea that our mental terrain decides what information survives in our heads and what gets killed off finds a parallel with a venerable biological theory: Darwin’s theory of natural selection. When we see lions and polar bears, we marvel at how well these animals have adapted themselves to the savannah and the polar ice caps. But no committee of lions sat down and decided that the African savannah would be home. No electoral bear-college voted for a leader who called for polar bears to move to the Arctic. These animals did not adapt to their environment, even though we use that figure of speech. Their environment adapted them to it.

Information, in this analogy, is our lion or polar bear. What gets inside our heads depends on the conditions our minds offer. If our minds offer savannah, lions thrive and polar bears die. If we have arctic chills, the polar bears live and the lions die.

This is why offering Obama’s birth certificate carries so little weight with people predisposed to buy the theory that the president was not born in the United States: It’s like setting a lion down on a polar icecap and expecting it to drive the polar bears into extinction. (Passionate Obama supporters similarly find convoluted ways to reject all criticism aimed at him. This isn’t a Republican or Democratic thing; it’s just the way our minds work.)

The natural-selection analogy is admittedly imperfect. Animals do not significantly alter their environments, but our minds both shape information and are shaped by it. Accurate information, moreover, is not completely powerless to change people’s minds; over time, it becomes harder and harder to deny reality. Finally, partisan commentary is increasingly organized and strategic, and probably shapes the long-term terrain on which our national conversation is carried out.

But the natural-selection analogy is a useful antidote to the surprise we profess when substantial numbers of people subscribe to smears, misinformation and even outright prejudice: Yes, it’s true that propagandists spout misinformation to serve their own ends, but if our minds were inhospitable to such garbage, the lies would die as quickly as that lion abandoned on an icecap.

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