以前から、地球温暖化についての世論は民主党支持・リベラルと、共和党支持・保守の間に大きな乖離があることがわかっていた。それを一歩踏み込んで調べたKahan[2014]をChris Mooneyが紹介している。

"Whether people 'believe in' climate change, like whether they 'believe in' evolution, expresses who they are," writes Kahan. To understand Kahan's analysis, it helps to start where much of his prior research―extensively covered by Klein, myself, and others―left off. Kahan has defined a measure that he calls "ordinary science intelligence," which assesses how good people are at mathematical and scientific reasoning and at questioning their own beliefs. Using this survey tool, he is able to present evidence showing that (1) as people get better at science, they are more likely in general to affirm that global warming is mostly due to human activities; but (2) as soon as you split people up in to liberals and conservatives, that conclusion goes out the window. Actually, liberals get way better in their answers as their science ability increases, and conservatives get considerably worse:

「人々が気候変動を『信じる』かは、進化論を『信じる」かと同様に、自分が何者であるかを表現している」とKahanは言う。Kahan(2014)の分析を理解するには、彼の前の研究から始めた方がいいだろう。Kleinや私自身や他はおいておこう。Kahanは一般科学知識水準と呼ぶ指標を定めた。これは、数学及び科学推論の能力を評価するもので、人々自身の信条を問うときに調べる。この調査道具を使うことで、彼は (1) 科学が得意であるほど、地球温暖化が主として人間活動によるものだと確信していて、(2) リベラルと保守に分割すると、結論はそうではなくなることを示す証拠を提示できた。実際、リベラルは科学の能力が高いほど正答率が高く、保守では正答率が低くなる。

[ Chris Mooney: "Conservatives Don't Deny Climate Science Because They're Ignorant. They Deny It Because of Who They Are." ]

Next, Kahan examined the patterns of responses based on ideology. This time, though, he no longer saw a performance split between those on the left and those on the right. Nor did he see a uniform pattern in which liberals tended to be more correct with higher levels of intelligence or science literacy, even as conservatives were more incorrect. Rather, sometimes the two groups were nearly the same in their performance, and sometimes one group did a little better or a little worse than the other:


[ Chris Mooney: "Conservatives Don't Deny Climate Science Because They're Ignorant. They Deny It Because of Who They Are." ]


What people “believe” about evolution likewise has zero correlation with what people know about the scientific evidence on the natural history of human beings or about any other insight human beings have acquired by use of science’s signature methods of observation, measurement, and inference. “Belief” and “disbelief,” too, are expressions of identity.

But precisely because that’s what they are−precisely b/c free and reasoning people predictably, understandably use their reason to form and persist in positions that advance their stake in maintaining bonds with others who share their outlooks−the teaching of evolution is fraught. I’m not talking about the politics of teaching evolution; that’s fraught, too, of course. I’m talking about the challenge that a high school or college instructor faces in trying to make it possible for students who live in a world where positions on evolution express who they are to actually acquire knowledge and understanding of what it is science knows about the natural history of our species.



To their immense credit, science education researchers have used empirical methods to address this challenge. What they’ve discovered is that a student’s “disbelief” in evolution in fact poses no barrier whatsoever to his or her learning of how random mutation and genetic variance combine with natural selection to propel adaptive changes in the forms of living creatures, including humans.

After mastering this material, the students who said they “disbelieved” still say they “disbelieve” in evolution. That’s because what people say in response to the “do you believe in evolution” question doesn’t measure what they know; it measures who they are.

Indeed, the key to enabling disbelievers to learn the modern synthesis, this research shows, is to disentangle those two things−to make it plain to students that the point of the instruction isn’t to make them change their “beliefs but to impart knowledge; isn’t to make them into some other kind of person but to give them evidence along with the power of critical discernment essential to make of it what they will.




[ Dan Kahan: "Why the science of science communication needs to go back to highschool (& college; punctuated with visits to museum & science film-making studio)" (2014/09/29) 0n The Cultural Cognition Project at Yale Law School ]