Here's why so many smart people don't believe in evolution

Does seeing the word "evolution" in a headline make you nervous?

It makes me nervous. Climate change may be the most politically charged scientific finding of the modern era, but the charged responses to it are nothing compared to people's forceful responses to evolution.

Gallup reports that 64% of US adults are worried "a great deal" or "a fair amount" about climate change, but only 50% believe in evolution. That's despite the fact that evolution is the foundation of all modern biology - not to mention much of modern medicine - and has been thoroughly investigated for the 157 years since Charles Darwin published "The Origin of Species."

The hair on the back of my neck stands on end when I get near this debate. One of my parents is a research mathematician; the other works in a biology lab. When I was a kid they made sure to talk about science with me, to help me see the elegance of Darwin's eons-long story of life. But we also lived in an Orthodox Jewish community, where schoolteachers laughed off dinosaurs and space travel as fairy tales and made a point of shutting down talk of evolution. It was the first in a series of conflicts that turned me away from that world.

But because of where I come from, I know lots of smart, thoughtful people who deeply believe that evolution is a crock. (And more who believe evolution was a God-guided process - along with the majority of Americans who accept the science.) I'm hostile to segments of the anti-religious crowd, including many scientists, who would shame religious people as fools.

That's why I was particularly interested in this paper by the psychologists Dan Kahan and Keith Stanovich, which re-examines some older data on why people do or do not believe in evolution.

First, the backstory. In 2015, the psychologists Will Gervais and Ara Nornzayan asked students to answer these three questions:

1. WIDGET. If it takes 5 machines 5 minutes to make 5 widgets, how long would it take 100 machines to make 100 widgets? ____ minutes
2. BATBALL. A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost? ____ cents
3. LILYPAD. In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half of the lake? ____ days

Take a second to think them over.

Together, these questions make up the Cognitive Reflection Test (CRT). The idea behind each of them is that they have an intuitive answer, one that seems obviously correct at first glance, that is different from its true answer. Psychologists believe the CRT is a good way to examine how talented a person is at reflecting on and, if necessary, rejecting their intuitive assumptions.

The obvious answer to question one is 100 minutes, because it follows the pattern of the question. But the correct answer is five minutes, because the we've already established that each machine takes five minutes to build a widget. For the second question, you want to guess $0.10, but if you do the math the correct answer is $0.05. And for the last question, the intuitive answer is 24 days but the correct answer is 47 days - because the patch had to double in size on the last day.

Gervais and Norenzayan found that students who didn't believe in evolution were somewhat more likely to get lower CRT scores, and students who did believe in evolution tended to get higher CRT scores.

We should be skeptical of anyone who publishes a study explaining why people who disagree with them are less clever.

They argued that this shows people tend to reject evolution due to "bounded rationality." That is, they see that iPhones, cars, and artwork are products of deliberate design, and are unable to escape their intuition that living things must be as well.

I'm going to be honest with you for a second about my biases: This kind of paper makes me a little angry. It strikes me as an attempt to marginalize and dismiss the perspectives of religious people for the benefit of Right-Thinking and Clever Academia. I suspect, personally, that a determined person could uncover any number of beliefs and attitudes held by academics that correlate with negative scores on tests of mental proficiency. All of which is to say: I think we should be skeptical of anyone who publishes a study explaining why people who disagree with them are less clever.

So I was pleased to see Kahan and Stanovich uncover a deeper story in Gervais and Nornzayan's data.

They replicated the original finding that anti-evolutionists tend to score somewhat lower on the CRT. But it turns out that there's a much stronger effect trending in exactly the opposite direction.

It turns out that high CRT scores most strongly predict that people will stick to their cultural beliefs about evolution. So very secular students with high CRT scores were likely to accept evolution, and very religious students with high CRT scores were likely to reject the science. Low CRT scores predict muddier, less culturally coherent views.

(When Kahan and Stanovich repeated the study on a national sample of 1,012 people they found the identical result.)

They suggest an alternative model of disbelief, which they call "expressive rationality." The theory is that people with highly developed mental tools for turning over and examining ideas are more skilled at explaining to themselves why they shouldn't - or should - accept a verifiable scientific claim.

It's a more challenging argument to accept, if you're a person who sees science as our only effective tool for extracting something like objective truth from an uncaring and chaotic universe - and who fears the consequences of rejecting it. It's far less comforting than telling yourself Oh, well those people are just dumb.

Folks who reject science, like the brilliant, infuriating Talmud scholars in my life, might not simply do so because they lack the brainpower to grasp it. Instead, they seem to arrive at their religious skepticism by their own extreme powers of persuasion - a highly developed ability to convince oneself that, rationally, the thing you believe is right. Oddly enough, that's the very same route that leads many secular people to place their faith in science.

What a scary thought.