In 2009, Politifact declared Sarah Palin's "death panels" fraud its "Lie of the Year." As it turns out, the Republican Party is the Home of the Whopper. Its followers, especially those most deeply steeped in the Tea Party's toxic brew, continue to believe claims about Barack Obama's faith, national origin, and tax cuts (just to name a few delusions) that are demonstrably false. Now, a growing body of research explains why. Rather than causing political partisans to rethink their positions, the presentation of contradictory facts instead causes them to dig in deeper.
The Boston Globe summed up the latest findings about political cognitive dissonance this weekend in an article titled, "political misperception:

Recently, a few political scientists have begun to discover a human tendency deeply discouraging to anyone with faith in the power of information. It's this: Facts don't necessarily have the power to change our minds. In fact, quite the opposite. In a series of studies in 2005 and 2006, researchers at the University of Michigan found that when misinformed people, particularly political partisans, were exposed to corrected facts in news stories, they rarely changed their minds. In fact, they often became even more strongly set in their beliefs. Facts, they found, were not curing misinformation. Like an underpowered antibiotic, facts could actually make misinformation even stronger.

The University of Michigan's Brendan Nyhan, co-author of "When Corrections Fail: The Persistence of Political Misperceptions," explained the fight-not-flight instinct in the face of unwelcome facts:

"The general idea is that it's absolutely threatening to admit you're wrong," says political scientist Brendan Nyhan, the lead researcher on the Michigan study. The phenomenon -- known as "backfire" -- is "a natural defense mechanism to avoid that cognitive dissonance."

Explaining how and why Americans vote as they do, especially when their choice seemingly fly in the face of their own self-interest, is a growing cottage industry. George Lakoff, Drew Weston and Thomas Frank are just some of the recent examples. (The rise of the "infotainment complex" and the devolution of politics into just another form of entertainment is another.)
But recent studies over the last several years suggest the strength of the "I Know I'm Right" syndrome. In 2000, an investigation by University of Illinois researcher James Kulinski revealed that the extent of political knowledge and the strength of political conviction are often inversely proportional:

He led an influential experiment in which more than 1,000 Illinois residents were asked questions about welfare -- the percentage of the federal budget spent on welfare, the number of people enrolled in the program, the percentage of enrollees who are black, and the average payout. More than half indicated that they were confident that their answers were correct -- but in fact only 3 percent of the people got more than half of the questions right. Perhaps more disturbingly, the ones who were the most confident they were right were by and large the ones who knew the least about the topic.

In 2005, Nyhan and his colleague Jason Reifler examined the "backfire" effect regarding the Iraq war, taxes and stem cell research. As the Washington Post summed up their findings:

Political scientists Brendan Nyhan and Jason Reifler provided two groups of volunteers with the Bush administration's prewar claims that Iraq had weapons of mass destruction. One group was given a refutation -- the comprehensive 2004 Duelfer report that concluded that Iraq did not have weapons of mass destruction before the United States invaded in 2003. Thirty-four percent of conservatives told only about the Bush administration's claims thought Iraq had hidden or destroyed its weapons before the U.S. invasion, but 64 percent of conservatives who heard both claim and refutation thought that Iraq really did have the weapons. The refutation, in other words, made the misinformation worse.
A similar "backfire effect" also influenced conservatives told about Bush administration assertions that tax cuts increase federal revenue. One group was offered a refutation by prominent economists that included current and former Bush administration officials. About 35 percent of conservatives told about the Bush claim believed it; 67 percent of those provided with both assertion and refutation believed that tax cuts increase revenue.

Of course, this pathology is not solely an affliction of the right. But as the Boston Globe noted, "The effect was slightly different on self-identified liberals." When provided with corrections about stem cells, "the corrections didn't backfire, but the readers did still ignore the inconvenient fact that the Bush administration's restrictions weren't total."
These results are in keeping with findings from other research in recent years. Studies have revealed that conservatives are much more uncomfortable with uncertainty than liberals. (This might explain in part why conservatives consistently report being happier than liberals, given their certainty about this life and the next.)
All of which suggests that Sarah Palin is just the latest - and most acute - symptom of the disease. After all, Palin and her followers remain convinced about everything from her Bridge to Nowhere, Democratic death panels and President Obama being in bed with big oil to the Constitution's roots in the "God of the Bible" and Palin's own energy expertise. No quantity or repetition of facts to the contrary will dissuade Palin and her followers. Their worldview is one of believing, not knowing.
As Brendan Nyhan lamented, "It's hard to be optimistic about the effectiveness of fact-checking."