Why conspiracy theories die hard

Or, why Usenet/politics boards are here to stay:

http://www.cnn.com/2011/OPINION/04/28/nyhan.birther.truth/index.html?hpt=Sbin

Editor's note: Brendan Nyhan, a political scientist, is a Robert Wood Johnson Scholar in Health Policy Research at the University of Michigan. He blogs at brendan-nyhan.com.

(CNN) -- Recent polls have found that as much as 15% to 20% of the public, including about 30% to 45% of Republicans, falsely believe that President Barack Obama was not born in this country. Will Wednesday's release of Obama's long-form birth certificate put an end to the birther myth?

The odds aren't good. The problem is that people can be extremely resistant to unwelcome factual information. In 2005 and 2006, I conducted a series of experiments to study this problem with Jason Reifler, a political scientist at Georgia State University.

In these studies, undergraduate participants were given news articles in which a political figure made a misleading claim. In some cases, this claim was followed by a correction that set the record straight. Disturbingly, we found that corrective information in news articles often fails to reduce misperceptions among the ideological or partisan group that is most vulnerable to the false belief.

In some cases, corrections even made misperceptions worse -- a result we call a "backfire effect."

Unfortunately, this sort of response is typical. Many other studies have found that people tend to resist or reject information, including scientific evidence, that contradicts their pre-existing views.

In research that is under way, Reifler and I provide evidence that this defensive response is driven by the threat that contradictory information poses to people's self-concept. When we first affirm individuals' self-worth, those who are most likely to be misinformed report substantially lower misperceptions.

In this case, the birther movement has grown to its current prominence despite the release of a certification of live birth and the discovery of contemporaneous announcements of Obama's birth in two Honolulu newspapers.

Given how much evidence is already available, it's hard to see why a long-form birth certificate would suddenly change the minds of people who are predisposed to believe in the myth. The hardcore are already shifting to new rationales for questioning Obama's right to hold office and deconstructing the PDF released by the White House for supposed evidence of forgery.

What's sad is that this myth should be relatively easy to quash -- a paper trail exists that definitively establishes Obama's place of birth. By contrast, many misperceptions cannot be directly disproved.

For instance, though the best available evidence shows that Saddam Hussein did not have weapons of mass destruction immediately before the U.S. invasion, it was not possible to prove that they weren't moved or hidden to the 50% of Americans who believed he did as late as 2006.

Similarly, though Obama is a practicing Christian, no one can prove that he is not secretly a Muslim, as some Americans have said to pollsters.

The best hope for killing this myth -- or any similar one -- is to create a bipartisan consensus that it is false. If conservative elites speak out aggressively against it, Republicans who are distrustful of Obama and the mainstream media might change their minds. Unfortunately, this seems unlikely -- the political incentives to pander to birthers are still too strong (as Donald Trump has recently demonstrated).

More realistically, the release of the birth certificate may limit elite support for birtherism. Prominent Republicans may make fewer pro-birther statements. Likewise, state-level efforts to require that presidential candidates demonstrate their eligibility for office may lose steam. In this way, the disclosure may reduce the media coverage that helps keep the myth alive.

But regardless of how events play out, the release of Obama's birth certificate should still be seen as a victory for misinformation.

A baseless charge has forced the president of the United States to go to unprecedented lengths to prove he is legally qualified to hold office -- a concession that seems likely to encourage the creation of more myths in the future.