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Dan Kahan brings the data

April 27, 2014

I’ve argued time and again (and again) that there’s no evidence believing in evolution is harmful. Dan Kahan shows how it’s really done by presenting, you know, some actual data. Here’s a sample:

Third, what people say they “believe” about evolution doesn’t reliably predict how much they know about science generally.

This is one of the lessons learned from use of the National Science Indicators.

The Indicators, which comprise a wide-ranging longitudinal survey of public knowledge, attitudes, and practices, offer a monumentally useful font of knowledge for the study of science and society. Indeed, they are a monument to the insight and public spirit of the scientists (including the scientist administrators inside the NSF) who created and continue to administer it.

Integral the the Indicators is a measure of “science literacy” that has been standardly employed in the social sciences for many years. The Indicators include a “knowledge” battery—an inventory-like set of “facts” such as the decisive significance of the father’s genes in determining the sex of a child and the size of an electron relative to that of an atom.

The indicators include two true-false items, which state “human beings, as we know them today developed from earlier species of animals,” and “the universe began with a huge explosion,” respectively. Test-takers who consistently get 90+% of the remaining  questions on the NSF test correct are only slightly more than 50% likely to correctly answer these questions, which are known as “Evolution” and “Big Bang” respectively.

That tells you something, or does if you are applying reason to observation: it is that “Big Bang” and “Evolution” aren’t measuring the same thing as the remaining items. In fact, research suggests—not surprisingly—that they are measuring a latent or unobserved “religiosity” disposition that is distinct from the latent knowledge of basic science the remaining questions are measuring.

What people are doing, then, when they say they “believe” and “disbelieve” in evolution is expressing who they are. Evolution has a cultural meaning, positions on which signify membership in one or another competing group.

People reliably respond to “Evolution” and “Big Bang” in a manner that signifies their identities.  Moreover, many of the people for whom “false” correctly conveys their cultural identity know plenty of science.

Accordingly, many social scientists interested in reliably measuring how disposed members of the public are to come to know what’s known by science, particularly across place and time, have proposed dropping “Big Bang” and “Evolution” — not from the survey regularly conducted by the NSF in compiling the Indicators, but from the scale one can form with the other items to measure what people know about what’s known to science.

This proposal has raised political hackles. How can one purport to measure science literacy and leave evolution and the big-bang theory of the origins of the universe out, they ask?  Someone who doesn’t know these things just is science illiterate!

Well, yes, if you simply define science literacy that way.  Moreover, if you do define it that way, you’ll be counting as “science literate” many people who harbor genuinely ignorant, embarrassing understandings of how evolution works.

Plus you’ll necessarily be dulling the precision of what is supposed to be an empirical measuring instrument for assessing what is known—since people who do know many many things will “say” they “don’t believe” in evolution. They’ll say that even if they — unlike the vast majority of the public who say they “believe” in evolution–are able to give an admirably cogent account of the modern synthesis.

Indeed, you’ll be converting what is supposed to be a measure of one thing—how much scientific knowledge people have acquired–into a symbol of something else: their willingness to assent to the cultural meaning that is conveyed by saying “true” to Evolution and Big Bang, as many people who do, and for that reason, without having any real comprehension of the science those items embody and without even doing very well on the remainder of the NSF Indicator battery.

Even then, the resulting “scale” won’t be a very reliable indicator of “identity,” since most of the remaining questions are ones that people whose identities are denigrated by answering “true” to Big Bang and Evolution are ones that bear no particular cultural meaning and thus don’t reliably even single out people of opposing cultural styles.

But insisting that the measure that social scientists use to study “science literacy” include Big Bang and Evolution under these circumstances will still convey a meaning.

It is that the enterprise of science is on one side of a cultural conflict between citizens whose disagreement about the best way of life in fact has nothing to do with the authority of science’s way of knowing, which in fact they all accept.

A “science literacy” test that insists that people profess “belief” in propositions that its citizens all understand to be expressions of cultural identity is really a pledge of allegiance, a loyalty oath to a partisan cultural orthodoxy.

And he drops the mic.

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One Comment leave one →
  1. Victor permalink
    April 27, 2014 1:43 pm

    Nice. No words after that.

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