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 (in addition, if one asks how many of the "believers" subscribe to a "naturalistic" or Darwinian view as opposed to a "theistic" variant, the proportion plummets down all the more-- for "Democrats" as well as "Republicans" blah blah blah).

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

Those who say they do "believe" are no more likely to be able 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 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.

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

Fantastic empirical research shows that it is very 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, etc., & 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 relative 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 predicated 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.

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.

This is very much related to what I have already recounted but is in fact a separate point.

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, not other way 'round-- check!") but rather an ability to 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."

The reason was simple: the answer people give to this question doesn't measure their comprehension of science. People who score at or near the top on the remaining portions of the test aren't any more likely to get this item "correct" than those who do poorly on the remaining portions.

What the NSF's evolution item does measure, researchers have concluded, is test takers' cultural identities, and in particular the centrality of religion in their lives.

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. The NSF regularly notes the controversy but prudently distances itself from what the significance of it.

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 (which is, ironically, the type of political regime most conducive to the advance of scientific discovery!) shouldn't equivocate.

We should insist that science comprehension be measured scientifically and point out the mistakes -- myriads of them -- being made by those who continue to insist that professions of "belief" in evolution are any sort of indicator of that.

I've reported some evidence before in this blog that reinforces the conclusion that "belief" in evolution is a measure of who people are and not what they know.

Well, here's some more.

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 = 2000) nationally representative sample earlier this month.

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

The second simply added to thist sentence the introductory clause, "According to the theory of evolution, ..."

The NSF had reported on a General Social Science module from a few years ago that found that the latter version elicits a much higher percentage of "true" responses.

Well, sure enough.

As the Figure at the top of the post shows, the proportion who selected "true" jumped from 55% on the NSF item to 81% on the GSS one!

Wow! Who would have thought it would be so easy to improve the "science literacy" of benighted Americans (who leaving aside the "evolution" and related "big bang" origin-of-the-universe items already tend to score better on the NSF battery than members of other industrialized nations).

Seriously: as a measure of what test takers know about science, there's absolutely no less content in the GSS version than the NSF. Indeed, if anyone who was asked to give an explanation for why "true" is the correct response to the NSF version failed to connect the answer to "evidence consisntent with the theory of evolution ..." would be revealed to have no idea what he or she is talking about.

The only thing the NSF item does that the GSS item doesn't is entangle the "knowledge" component of the "evolution" item (as paltry as it is) in the identity-expressive significance of "positions" on evolution.

Want some more evidence? Here you go:



This figure shows the relationship between the probability of a "true" response to the respective versions of the question conditional "religiosity" & "science comprehension." (The figure graphically reports the results of a regression model. If you want to see the raw Click me--I will make you more science literate, I swear!data, click on the inset to the left!)

The former was measured by aggregating into a scale responses to items on self-reported frequency of church attendance, frequency of prayer, and importance of God (α = 0.87).

The latter was formed by combining the NSF's science indicator battery (excluding the "evolution" one, to avoid circularity) with a set of Numeracy and Critical Reflection Test items. The NSF indicators, a collection of "true-false" items, can be seen as comprising knowledge of elementary facts; the additional items assess the sorts of reasoning skills--including, in particular, the disposition and ability to make valid inferences from quantitative and other forms of information--that a person needs in order reliably to acquire scientific knowledge.

The items cohere nicely, forming a highly reliable unidimensional scale (α = 0.84), which I scored with an item response theory model.

Indeed, the main reason for collecting data on the GSS and NSF variants of the evolution item was to see what the frequency of "true" responses to them would reveal about the item's relative connection to religious identity and science comprehension.

These data answer that question.

The panel on the left confirms that the NSF item does indeed measure religious identity, not scientific knowledgeable.

Or maybe one can see it as indicating science comprehension for relatively secular folks, since in them one sees what one would expect if that were the case--namely, that the probability of answering "true" goes up as people become progressively more comprehending of science.

But the probability of answering "true" doesn't go up--if anything it goes down--as individuals who are above average in religiosity become more science comprehending. That's manifestly inconsistent with any inference that the answer to the question indicates the science comprehension of people with a more religious identity. (In case you were wondering -- and it's perfectly reasonable to -- there was a fairly minor negative correlation-- r = - 0.17, p < 0.01-- between religiosity and science comprehension.)

Now behold the panel on the right!

Here we do see exactly what one would expect of an item that indicates (i.e., correlates, because it's presumably caused by) science comprehension--an increasing probability of answering "true" -- for both non-religious and religious individuals!

By adding the introductory clause, "According to the theory of evolution," the GSS question disentangles ("unconfounds" in psychology-speak) the "science knowledge" component and the "identity expressive" components of the item.

Gee, Americans aren't that dumb after all!

Or maybe they are; this is too easy a question if one wants to figure out whether Americans or anyone else really knows anything about science: some 80% of the respondents answer it correctly -- a figure that rapidly approaches 100% among those of even middling science comprehension.

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 graph above and then respond to the item,

"'Belief in evolution' is a valid measure of a person's science literacy," true or false?