Why science can't hold sway

Whether the experts were regarded as credible depended on a person's preexisting beliefs.
Whether the experts were regarded as credible depended on a person's preexisting beliefs.

Our biases are overpowering.

Posted: September 20, 2010

Why do so many Americans disagree with scientific consensus on issues such as global climate change and the safety of burying nuclear waste? Is it our poor education? Science illiteracy? Innumeracy?

None of the above, according to a new study published in Journal of Risk Research. People's positions on these issues and their willingness to believe or discount scientists depends mostly on ideology, or what the study's authors call "cultural cognition."

After surveying 1,500 people, the researchers found that those who were "egalitarian and resentful of economic inequality" were more likely to assume that there was scientific consensus that human activity is contributing to climate change, but not that it's safe to dispose of nuclear waste underground. Those who were more "hierarchical, individualistic and connected to industry and commerce" were more likely to make the opposite assumptions.

According to reports from the National Academy of Sciences, human activity is contributing to climate change and nuclear waste can be buried safely in certain designated sites.

"It's not that one group is paying more attention to what scientific consensus is," said Dan Kahan, a law professor at Yale and author of the study. But there's a pervasive tendency to form perceptions of scientific consensus that reinforce people's values.

The researchers also confronted subjects with fictional authors - Robert Linden, professor of meteorology at MIT; Oliver Roberts, professor of nuclear engineering at U.C. Berkeley; and James Williams, professor of criminology at Stanford. All had Ivy League Ph.D.s and membership in the National Academy of Sciences.

Subjects were asked whether they'd recommend a book by any of these authors to a friend.

The result: The experts could be seen as sages or stooges depending on whether they were said to agree with a subject's preexisting belief.

Sure, professor Roberts might have a Ph.D. from Princeton but if he's going to panic about nuclear waste he must be a girly man - or if he thinks it's safe to bury it, someone in the nuclear industry must be paying him.

It's not that people don't like science - it's that they selectively attend to evidence in a way that's gratifying to them, said Kahan. "People will do that with our article," he said. "They'll say that's why those people [who disagree with them] are so dumb."


Contact staff writer Faye Flam at 215-854-4977 or fflam@phillynews.com.

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