By Brendan Nyhan
Do Americans understand the scientific consensus about issues like climate change and evolution?
At least for a substantial portion of the public, it seems like the answer is no. The Pew Research Center, for instance, found that 33 percent of the public believes “Humans and other living things have existed in their present form since the beginning of time” and 26 percent think there is not “solid evidence that the average temperature on Earth has been getting warmer over the past few decades.” Unsurprisingly, beliefs on both topics are divided along religious and partisan lines. For instance, 46 percent of Republicans said there is not solid evidence of global warming, compared with 11 percent of Democrats.
As a result of surveys like these, scientists and advocates have concluded that many people are not aware of the evidence on these issues and need to be provided with correct information. That’s the impulse behind efforts like the campaign to publicize the fact that 97 percent of climate scientists believe human activities are causing global warming.
In a new study, a Yale Law School professor, Dan Kahan, finds that the divide over belief in evolution between more and less religious people iswider among people who otherwise show familiarity with math and science, which suggests that the problem isn’t a lack of information. When he instead tested whether respondents knew the theory of evolution, omitting mention of belief, there was virtually no difference between more and less religious people with high scientific familiarity. In other words, religious people knew the science; they just weren’t willing to say that they believed in it.
Mr. Kahan’s study suggests that more people know what scientists think about high-profile scientific controversies than polls suggest; they just aren’t willing to endorse the consensus when it contradicts their political or religious views. This finding helps us understand why my colleagues and I have found that factual and scientific evidence is often ineffective at reducing misperceptions and can even backfire on issues like weapons of mass destruction, health care reform and vaccines. With science as with politics, identity often trumps the facts.