The Atlantic

Sometimes small influences can be important, and sometimes studies really are worth their press releases. It’s relevant that people whose polling places are schools are more likely to vote for sales taxes that will fund education. Or that judges become more likely to deny parole the longer they go without a break. Or that people serve themselves more food when using a large plate. Such effects, even when they’re small, can make a practical difference, especially when they influence votes and justice and health. But their existence doesn’t undermine the idea of a rational and deliberative self. To think otherwise would be like concluding that because salt adds flavor to food, nothing else does.

We’re at our worst when it comes to politics. This helps explain why recent attacks on rationality have captured the imagination of the scientific community and the public at large. Politics forces us to confront those who disagree with us, and we’re not naturally inclined to see those on the other side of an issue as rational beings. Why, for instance, do so many Republicans think Obama’s health-care plan violates the Constitution? Writing in The New Yorker in June 2012, Ezra Klein used the research of Haidt and others to argue that Republicans despise the plan on political, not rational, grounds. Initially, he notes, they objected to what the Democrats had to offer out of a kind of tribal sense of loyalty. Only once they had established that position did they turn to reason to try to justify their views.

But notice that Klein doesn’t reach for a social-psychology journal when articulating why he and his Democratic allies are so confident that Obamacare is constitutional. He’s not inclined to understand his own perspective as the product of reflexive loyalty to the ideology of his own group. This lack of interest in the source of one’s views is typical. Because most academics are politically left of center, they generally use their theories of irrationality to explain the beliefs of the politically right of center. They like to explore how psychological biases shape the decisions people make to support Republicans, reject affirmative-action policies, and disapprove of homosexuality. But they don’t spend much time investigating how such biases might shape their own decisions to support Democrats, endorse affirmative action, and approve of gay marriage.