Cognitive reflection and "belief in" evolution: critically engaging the evidence - Cultural Cognition of Health

Why do 45% or so of Americans consistently say they don’t “believe” humans evolved from an earlier species?

How come about only one-third of them say they accept a conception of evolution—science’s conception—that features  mechanisms of natural selection, random mutation, and genetic variance  (the modern synthesis) as opposed to an alternative religious one that asserts a “supreme being guided the evolution of living things for the purpose of creating humans and other life in the form it exists today?”

These questions get asked constantly. Makes sense: they’re complicated,  and also extremely consequential for the status of science in a liberal democratic society.

One popular answer attributes “disbelief in” evolution to a defecit in critical reasoning that interferes with people’s ability to recognize or accept scientific evidence. I’ve referred to this i n other contexts as the “public irrationality thesis” (PIT) (Kahan in press).

Actually, I think PIT, while a plausible enough conjecture, is itself contrary to weight of the scientific evidence on who believes what and why about human evolution.

It’s well established that there is no meaningful correlation between what a person says he or she “believes” about evolution and having the rudimentary understanding of natural selection, random mutation, and genetic variance necessary to pass a high school biology exam (Bishop & Anderson 1990; Shtulman 2006).

There is a correlation between “belief” in evolution and possession of the kinds of substantive knowledge and reasoning skills essential to science comprehension generally.

But what the correlation is depends on religiosity : a relatively nonreligious person is more likely to say he or she “believes in” evolution, but a relatively religious person less likely to do so, as their science comprehension capacity goes up (Kahan 2015).

That’s what “belief in” evolution of the sort measured in a survey item signifies: who one is, not what one knows.

Americans don’t disagree about evolution because they have different understandings of or commitments to science.  They disagree because they subscribe to competing cultural worldviews that invest positions on evolution with identity-expressive significance.

As with the climate change debate, the contours and depth of the divide on evolution are a testament not to defects in human rationality but to the adroit use of it by individuals to conform their “beliefs” to the ones that signal their allegiance to groups engaged in a ( demeaning, illiberal, and unnecessary ) form of cultural status compeitition.

Call this the “expressive rationality thesis” (ERT). It’s what I believe—on the basis of my understanding of the best currently available evidence (Kahan 2015).

But if one gets how science works, then one knows that all one’s positions—all of one’s “beliefs”—about empirical issues are provisional.  If I encounter evidence contrary to the view I just stated, I’ll revise my beliefs on that accordingly ( I’ve done it before ; it doesn’t hurt!).

So I happily sat down last weekend to read Gervais., W, “Override the controversy: Analytic thinking predicts endorsement of religion,” Cognition, 142, 312-321 (2015).

Gervais is a super smart psychologist at the University of Kentucky. He’s done a number of interesting and important studies that I think are really cool, including one  that shows that people engage in biased information processing to gratify their animus against atheists (Garvais, Shariff & Norenzayan 2011), and another that reports a negative association between critical reasoning and religiosity (Gervaise & Norenzayan 2012).

In this latest study, Gervais correlated the scores of two samples of Univ. of Kentucky undergrads on the Cognitive Reflection Test (CRT) and their beliefs on evolution.

As discussed in 327 previous posts, the CRT  is regarded as the premiere measure of the capacity and disposition to use conscious, effortful, “System 2” information processing as opposed to unconscious, heuristic “System 1” processing, the sort that tends to be at the root of various cognitive miscues, from confirmation bias to the gambler’s fallacy, from base rate neglect to covariance non-detection (Frederick 2005).

Gervais hypothesized that disbelief in evolution is associated with overreliance on “intuitive” or heuristic “System 1” forms of information processing as opposed to conscious or “analytic” “System 2” forms.

“[M]any scientific concepts are difficult for people to grasp intuitively while supernatural concepts may come more easily,” he explains.

From a young age, children view things in the world as existing for a reason; they view objects as serving functions. This promiscuous teleology persists into adulthood, even among those with advanced scientific training. Further, functionally specialized features of animals (such as a zebra’s stripes or a kangaroo’s tail) are viewed as inherently characteristics of an animal’s ‘‘kind,’’ perhaps implying a deeper and more temporally stable essence of the animal. If objects in the world, including living things, are intuitively imbued with function and purpose, it seems a small step to viewing them as intentionally designed by some external agent. . ..