Weekend Update: You'd Have to Be Science Illiterate to Think "Belief in Evolution" Measures Science Literacy

It's been soooo long — at least 3 weeks! — since I last did a post on the relationship between "belief in evolution" & "science literacy."

That's just not right! Plus I have some cool new data on this issue.

But let's start with a reprise of the basics — because one can never overstate how aggressively ignored they are by those who flip out & let loose with a toxic stream of ignorance & cultural zealotry every time a polling organization announces the "startling" news that nearly 50% of the US public continues (as it has for decades) to say "no" when asked whether they believe in evolution.

Zero Correlation Between "Believing" and Understanding Evolution

First, there is zero correlation between saying one "believes" in evolution and understanding the rudiments of modern evolutionary science.

Those who say they do "believe" are no more likely to be able to give a high-school-exam passing account of natural selection, genetic variance, and random mutation — the basic elements of the modern synthesis — than those who say they "don't" believe.

In fact, neither is very likely to be able to, which means that those who "believe" in evolution are professing their assent to something they don't understand.

That's really nothing to be embarrassed about: if one wants to live a decent life — or just live, really — one has to accept much more as known by science than one can comprehend to any meaningful degree.

What is embarrassing, though, is for those who don't understand something to claim that their "belief" in it demonstrates that they have a greater comprehension of science than someone who says he or she "doesn't" believe it.

"Disbelief" in Evolution Is No Barrier to Learning It

Second, "disbelief" in evolution poses absolutely no barrier to comprehension of basic evolutionary science.

Fantastic empirical research shows that it is very possible for a dedicated science educator to teach the modern synthesis to a secondary school student who says he or she "doesn't believe" in evolution.

The way to do it is to do the same thing that one should do for the secondary school student who says he or she does believe in evolution & who, in all likelihood, doesn't understand it: by focusing on correcting various naive misconceptions that have little to do with belief in the supernatural, and everything to do with the ingrained attraction of people to functionalist sorts of accounts of how natural beings adapt to their environments.

The thing is, though, even after acquiring knowledge of the modern synthesis — likely the most awe-inspiring & elegant, not to mention astonishingly useful, collection of insights that human reason has ever pried loose from nature — the bright kid who before said "no" when asked if he or she "believes" in evolution is not any more likely to say that he or she now "believes" it.

Indeed, confusing "comprehension" with profession of "belief" is a very good way to assure that those kids who are disposed to say they "don't believe" won't learn these momentous insights.

As Lawson & Worsnop observed in the conclusion of their classic study (the one that presented such amazingly cool evidence on how to teach evolution in a way that excited kids of all cultural outlooks to want to learn it):

[E]very teacher who has addressed the issue of special creation and evolution in the classroom already knows that highly religious students are not likely to change their belief in special creation as a consequence of relatively brief lessons on evolution. Our suggestion is that it is best not to try to do so, not directly at least. Rather, our experience and results suggest to us that a more prudent plan would be to utilize instruction time, much as we did, to explore the alternatives, their predicted consequences, and the evidence in a hypothetico-deductive way in an effort to provoke argumentation and the use of reflective thought.

Thus, the primary aims of the lesson should not be to convince students of one belief or another, but, instead, to help students (a) gain a better understanding of how scientists compare alternative hypotheses, their predicted consequences, and the evidence to arrive at belief and (b) acquire skill in the use of this important reasoning pattern — a pattern that appears to be necessary for independent learning and critical thought.

There are actually some who say in response, "Not good enough; it is essential not merely to impart knowledge but also to extract a profession of belief too!"

When someone says that, he or she helps us to see that there are actually illiberal sectarians on both sides of the "evolution in education" controversy in this society.

"Belief" in Evolution Is Not a Valid Measure of Science Comprehension

Third — and here we are getting to the point where the new data come in! — profession of "belief" in evolution is simply not a valid measure of science comprehension.

Because imparting basic comprehension of science in citizens is so critical to enlightened democracy, it is essential that we develop valid measures of it, so that we can assess and improve the profession of teaching science to people.

What should be measured, in my view, is a quality of ordinary science intelligence — not some inventory of facts ("earth goes 'round the sun — check!") but rather an ability to distinguish valid from invalid claims to scientific insight and a disposition to use in one's own decisions science's signature style of inference from observation.

The National Science Foundation has been engaged in the project of trying to formulate and promote such a measure for quite some time. A few years ago it came to the conclusion that the item "human beings, as we know them today, developed from earlier species of animals" shouldn't be included when computing "science literacy."

Predictably, the NSF was forced to back off this position by a crescendo of objections from those who either couldn't get or didn't care about the distinction between measuring science comprehension and administering a cultural orthodoxy test.

But those of us who don't have to worry about whether taking a stance will affect our research budgets, who genuinely care about science, and who recognize the challenge of propagating widespread comprehension and simple enjoyment of science in a culturally pluralistic society shouldn't equivocate.

New Empirical Data: The NSF vs. GSS Evolution Item

Following up on a super interesting tidbit from the 2014 NSF Science Indicators, I included alternate versions of the conventional NSF Indicator "evolution" item in a science comprehension battery that I administered to a large (N = 2,000) nationally representative sample.

One was the conventional "true-false" statement: "Human beings, as we know them today, developed from earlier species of animals."

The second simply added the introductory clause: "According to the theory of evolution, …"

What the Regression Model Shows

The religious identity measure was formed by aggregating responses to items on self-reported frequency of church attendance, frequency of prayer, and importance of God (α = 0.87). The science comprehension measure combined the NSF science indicator battery (excluding the evolution item) with Numeracy and Critical Reflection Test items (α = 0.84), scored with an item response theory model.

Left panel (NSF item): Among relatively secular respondents, the probability of answering "true" increases with science comprehension — as expected. But among individuals with above-average religiosity, the probability doesn't increase — if anything it goes down — as their science comprehension rises. This is manifestly inconsistent with any inference that the NSF item indicates the science comprehension of more religious people.

Right panel (GSS item): Here we do see exactly what one would expect of an item that actually measures science comprehension — an increasing probability of answering "true" for both non-religious and religious individuals. By adding the introductory clause, the GSS question disentangles (or "unconfounds," in psychology-speak) the knowledge component from the identity-expressive component.

The Real Test

So ditch this question & substitute for it one more probative of genuine science comprehension — like whether the test taker actually gets natural selection, random mutation, and genetic variance, which are of course the fundamental mechanisms of evolution and which kids with a religious identity can be taught just as readily as anyone else.

Or actually, how about this. Instruct the test taker to reflect on the data above and then respond to the item: