Joe Keohane:

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.

This bodes ill for a democracy, because most voters -- the people making decisions about how the country runs -- aren't blank slates. They already have beliefs, and a set of facts lodged in their minds. The problem is that sometimes the things they think they know are objectively, provably false. And in the presence of the correct information, such people react very, very differently than the merely uninformed. Instead of changing their minds to reflect the correct information, they can entrench themselves even deeper.

"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."

These findings open a long-running argument about the political ignorance of American citizens to broader questions about the interplay between the nature of human intelligence and our democratic ideals. Most of us like to believe that our opinions have been formed over time by careful, rational consideration of facts and ideas, and that the decisions based on those opinions, therefore, have the ring of soundness and intelligence. In reality, we often base our opinions on our beliefs, which can have an uneasy relationship with facts. And rather than facts driving beliefs, our beliefs can dictate the facts we chose to accept. They can cause us to twist facts so they fit better with our preconceived notions.

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