in her book The Sociopath Next Door, she quoted murderer Barbara Graham: “Good people are always so sure they’re right.”

Wrong, says Stout: Good people are forever wondering if they’re right, questioning themselves, striving to be better. While it would be foolish to argue that only liberals are good people, psychologists are finding that the tolerance of ambiguity and an urge to cogitate are core liberal traits, just as resistance to change and a need for closure are among the traits of conservatives.

That such qualities should segregate across the political spectrum may strike us as intuitively correct but potentially dangerous. But the science is in: Conservatives’ and liberals’ psychologies—-their needs, cognitive styles, moral intuitions, their very brains—-are markedly different. So are their strengths and weaknesses. With its denial of evolution, global warming, and much else in science (not to mention history), the American right is earning a reputation for indifference to reality. Why do Republicans resist the facts?

“It turns out that there are facts about why we deny facts,” writes veteran science journalist Chris Mooney. For a long time, he says, he believed that conservative intransigence to fact was a “strange-bedfellows effect” brought on by alliances among big business, religious conservatives, and the right. His 2005 book The Republican War on Science espoused this explanation. But Mooney now believes that the political environment—and even the way modern media allow selective exposure to fact—is only half the story.

In this nuanced and fascinating tour of neuroscience, linguistics,and experimental psychology—which references the work of researchers like John Jost, Drew Westen, and George Lakoff—Mooney shows us how the other half thinks. Conservatives’ brains have larger amygdalas, he writes; liberals’ brains are larger in an area involved with error detection. Conservatives’ startle reflexes are keener. Children who grow up to be conservative show a greater need to control their environment as early as age 3. In moral matters, conservatives care about protection from harm, fairness, loyalty, obedience, and preservation of purity; liberals care mostly about the first two. Even the stuff adults keep in their bedrooms is weirdly partisan (conservatives: organizers, flags, sports equipment; liberals: books, music, art supplies). And the tendency to argue against fact seems stronger, not weaker, in more educated conservatives, perhaps because the telos of human reason may be persuasion, not discovery. Interestingly, you can go some way toward turning liberals into conservatives, at least temporarily. How? By frightening them, distracting them, or getting them drunk.

Mooney remarks that he admires conservatives, which may ring hollow. But he does make a case for their virtues, not least by suggesting that to be politically effective, liberals need to behave more like the right: Unite, stop dithering, and use emotionally moving narratives to make their points. Most of all, he argues, liberals need to drop their Enlightenment misconception that careful argument and the dissemination of facts will stamp out misinformation. It won’t—-and given what we know of conservative psychology, it is in itself a kind of reality-denial to expect such tactics to succeed.

Mooney is open about his own liberalism, and the book is unlikely to charm conservatives. But he earns additional credibility by airing liberals’ own weaknesses, such as the qualitatively different way that they mishandle science around issues like vaccines and fracking, and how they themselves engage in emotion-based “motivated reasoning.”

In any case, it’s hard for even an anti-authoritarian liberal reader not to trust a writer who includes so many caveats. “How do I know I’m right?” Mooney asks. “Because I’m willing to be wrong.” Amen.
Jenny Blair is a writer, editor, and M.D. Her website is www.jennyblair.com.