Lately, though, an explanation of flawed risk assessment has become popular that has the virtue of not dismissing half the population as ignorant, stupid, or biased by temperament. It’s called the cultural cognition of risk, and its best-known advocate is a handsome, puckish law and psychology professor at Yale named Dan Kahan. He thinks misperceptions of risk make perfect sense if you view them in a social context. First, says Kahan, rid yourself of the thought that Americans distrust science, scientists, or the scientific consensus. Consider this line from a 2009 Pew Research report: “Overwhelming majorities say that science has had a positive effect on society and that science has made life easier for most people.” What they disagree about is what the science says. People assimilate the data and choose the experts that fit most neatly with their and their peers’ values. Kahan and colleagues like to plot these worldviews on charts that illustrate how certain sociocultural tendencies—hierarchical-individualist and egalitarian-communitarian are the two big ones—consistently correlate to the same judgments about what’s worrisome and what isn’t.

Risk assessment by groupthink is reasonable, if not rational, because, at the personal level, it costs nothing. If you misconstrue the nature of a global threat, your mistake won’t hurt you much, because you can’t save yourself anyway. But if you contradict your friends or powerful members of your group—that could cost you dearly. (Incidentally, Kahan sees evidence of scientific groupthink on both sides of the ideological spectrum.) Kahan’s most provocative finding, though, is that people better at “cognitive reflection,” or slow, probing thought, are actually more likely to arrive at predetermined conclusions about risk, not less. The urge to maintain status within one’s social network is so powerful, Kahan told me, that well-educated people will use their information-gathering and computational skills to marshal a more impressive body of evidence in support of whatever identity it is (freethinking skeptic, caring mother hen) that earns them brownie points in their troop. On his blog, he once called these strong in-group effects “tapeworms of cognitive illiberalism” and a dispiriting omen for democracy.

Kahan’s conclusions wouldn’t surprise anyone who has spent her life studying politics. Political theorists have been working out for decades how the interests of individuals and small groups obstruct the interests of the collective and why it’s so hard to get people to act on threats they can’t see or feel. According to Kahan, what cultural cognition theory has to add is the science of science communication. He and his kind conduct research on how to present science so that it won’t be entangled with issues of “membership and loyalty to a group.”

So what would he tell the environmentalists? The key is “not to use language or modes of communication that convey animosity, contempt, and hostility,” he told me, because then “the signal that will come through is ... that our group is under assault.” I wasn’t able to force any good examples out of him, though I couldn’t help suspecting that one tactic would be to play down the words “United Nations,” since that body, as everybody knows, flies black helicopters and encroaches on U.S. sovereignty. But I’d guess that Harvard political scientist and sociologist Theda Skocpol, for one, wouldn’t think Kahan could tell the environmentalists much. In a recent and devastating post-mortem on the failed attempt to pass cap-and-trade legislation in President Obama’s first term, she was contemptuous of the kind of politics that relies on “messaging campaigns,” as she calls them. “The new vogue to pay psychological researchers to come up with phrases that subliminally appeal to individuals,” she wrote, is “a waste of resources.” She’d rather have green groups put their money into boots-on-the-ground, precinct-by-precinct, Tea Party–style organizing. I read Kahan that passage and he countered by asking what message Skocpol’s organizers would offer up, and how they’d know whether it would work if they didn’t test it with “evidence-based methods.”