Both Slate and the Washington Post have interesting new article summarizing recent social science research showing that voters tend to be highly biased in their evaluation of political information. Voters tend to overvalue the importance of new information that supports their preexisting views or makes their preferred party look good; and they tend to discount any information that cuts the other way. As the Slate article puts it:

This has nothing to do with ideology. Politics isn't about ideology. It's about joining a team, and we judge fairness as partisans. In 1951, Princeton and Dartmouth students watched a film of a football game and were asked to take note of foul play. Princeton stalwarts saw all the penalties that should have been called on the Dartmouth players. Dartmouth students were convinced the refs missed clips and offsides committed by the Princeton players.

We judge politics the same way—as team members, not truth-seekers. Last week the Washington Post reported on a slew of experiments showing that political misinformation feeds people's pre-existing beliefs.

These findings - and the sports analogy that goes with them - are not new. I summarized earlier findings of this type in a 2006 article in which I similarly compared political partisans to sports fans.

The interesting question is why voters behave like biased sports fans instead of trying to evaluate new political information in an unbiased way. After all, isn't politics far more important than sports, deserving of a more serious effort to get at the truth?

The answer I gave in the article is that political fans are similar to sports fans in so far as both have little or no incentive to be truth-seekers. Because there is little or no chance that your vote will be decisive in an election, voters whose only reason to acquire political information is to do a better job of choosing the "right" candidate tend to be "rationally ignorant." Those who do acquire political information are likely to do so for other reasons - reasons that have little to do with truth-seeking. Here's a brief relevant excerpt from the article (pp. 260-61):

[T]he theory of rational ignorance does not predict that voters will choose not to acquire any information at all. Rather it predicts that they will acquire very little or no information for purposes of voting However, some voters will acquire information for other reasons....

A useful analogy is to sports fans. Fans who acquire extensive knowledge of their favorite teams and players do not do so because they can thereby influence the outcome of games. They do it because it increases the enjoyment they get from rooting for their favorite teams. But if many of the citizens who acquire significant amounts of political knowledge do so primarily for reasons other than becoming a better voter, it is possible that they will acquire the knowledge that is of little use for voting, or will fail to use the knowledge they do have in the right way.

Here again, a sports analogy may be helpful. Committed Red Sox fans who passionately root against the Yankees are unlikely to evaluate the evidence about these teams objectively. The authors of one recent history of the Red Sox and Yankees note that they chose not to write “a fair and balanced look at the Red Sox-Yankees ‘rivalry,’” because “neither author of this book wanted to represent the Yankees [sic] point of view. . . . Neither of us could bring ourselves to say enough complimentary things about [the Yankees] to fill the back of a matchbox, let alone half a book” (Nowlin and Prime 2004, 4). . . Similarly, Democratic partisans who hate George W. Bush, and Republicans who reflexively support him against all criticism, might well want to acquire information in order to augment the experience of cheering on their preferred political “team.” If this is indeed their goal, neither group is likely to evaluate Bush’s performance in office objectively or accurately.

This intuition is confirmed by studies showing that people tend to use new information to reinforce their preexisting views on political issues, while discounting evidence that runs counter to them . . . Although some scholars view such bias as potentially irrational behavior . . . , it is perfectly rational if the goal is not to get at the “truth” of a given issue in order to be a better voter, but to enjoy the psychic benefits of being a political “fan.”

Candidates and the media understand the biases of "political fans" and often exploit them for their own benefit.

How do we get out of the dangerous box in which public policy is determined in elections where most voters are either rationally ignorant about even basic political information or highly biased in their evaluation of what they do know? There is no easy answer to that question. In the article linked above and in some of my other scholarship (e.g. - here), I suggest that we consider making fewer decisions through the political system and more through free markets and civil society - where people have much stronger incentives to both seek out information and evaluate it at least somewhat rationally.