Will Saletan has an amazing, thoughtful, and compelling essay on Slate, exploring the hypocrisy and science denial of certain GMO opponents. Connoisseurs of science denial will recognize many of the tactics he documents, from misuse of statistics and personal attacks on scientists, to imputations of sinister motives when leading science bodies express a consensus (here, that the underlying techniques are safe), and shifting goalposts and double standards (impossibly high for the scientists, implausibly low for the deniers).

This isn’t a topic we’ve spent much time on at NCSE, since genetic engineering is not typically part of the K-12 curriculum, and we haven’t heard of many cases where the public battles over the science of genetic engineering have been dragged into the classroom. And there are various non-scientific aspects to those debates that would lie beyond our scope anyway: patent law and agricultural policy being chief among them. But there’s a clear scientific consensus that the basic technologies involved in producing genetically modified organisms are safe, and we now have decades of experience with the most widespread forms of GMOs on which to judge them safe, too. And there are some aspects in common with the science denials we’re more accustomed to: in a recent survey by Pew, the safety of GMOs was the topic with the greatest divergence in attitude between the public and scientists, greater than evolution or climate change, even. As Saletan points out, this disconnect and denial has harmful consequences. The continuing vitriolic battle over the basic technology has largely cleared the market of anyone who isn’t primarily driven by profit rather than humanitarian interest, thus intensifying the potential for abuse and denying people the greatest possible benefits.

There’s an aspect of Saletan’s piece that struck me as a bit off, though. In the final paragraph, he writes that we haven’t seen the full benefits of genetic engineering yet:

because we’ve been stuck in a stupid, wasteful fight over GMOs. On one side is an army of quacks and pseudo-environmentalists waging a leftist war on science. On the other side are corporate cowards who would rather stick to profitable weed-killing than invest in products that might offend a suspicious public. The only way to end this fight is to educate ourselves and make it clear to everyone—European governments, trend-setting grocers, fad-hopping restaurant chains, research universities, and biotechnology investors—that we’re ready, as voters and consumers, to embrace nutritious, environmentally friendly food, no matter where it got its genes.

While I agree with most of that argument, by calling it “a leftist war on science,” Saletan seems to suggest that the issue is politically polarized in the way that climate change is, or abortion, or evolution.

But it isn’t.

Looking at public opinion on GMOs, we find pretty consistently that there's little political polarization at all. In 2013, Chris Mooney (something of an expert on partisan wars on science), summarized the public polling data, “while resistance may be strongest on the far left, worries on this issue are quite prominent across the spectrum as well. In neither case [vaccines or GMOs] are these beliefs a mirror image, on the left, of climate change or evolution denial.”

Dan Kahan, who studies how people's cultural affiliations shape their attitudes on these sorts of issues, summarizes his research on attitudes toward GMOs by saying “GM foods in US is not a focus for cultural polarization in the public as of now.”

He also notes:

There are a variety of interest groups that keep trying to turn GM foods into a high-profile issue that divides citizens along the lines characteristic of disputed environmental and technological risk issues like climate change and nuclear power. But they just can’t manage to reproduce here the level of genuine cultural contestation that exists in Europe. Why they can’t is a really interesting question; indeed, it’s really important, since it isn’t possible to figure out why some risks become the source of such divisions without exam[in]ing both technologies that do become the focus of polarization and those that don’t.

In a lengthy and cordial exchange with me on Twitter, Saletan emphasized that he wasn’t trying to make a point about public attitude but about who was pushing this fight, that the most vocal leaders of the anti-GMO camp are from the political left. But that alone doesn’t make this a partisan war.

If this issue were contentious because of the actions of liberal activists (or environmentalists), we’d expect to see it being a focus primarily among those who affiliate with liberal and environmental causes. That’s certainly the pattern with climate change. And with evolution, we see the issue polarized because 90 years ago the nascent fundamentalist movement chose to make evolution one of their markers of identity, and theological conservatives continue to reject that science.

But that isn’t the pattern with genetic engineering, and that’s important. Either it means that groups like Greenpeace are about as influential among conservative Republicans as among liberal Democrats, or that the influence of groups like Greenpeace on public opinion about this issue has been pretty minimal.

The latter hypothesis seems far more plausible, but I probed the issue using data from the 2006 General Social Survey (a huge biennial survey that explores many issues, including GMO safety that year). In that survey, 1 in 3 people who called themselves “extremely liberal” or “liberal” said that they “Will not eat genetically modified food.” The numbers were essentially identical among those who call themselves “extremely conservative” or “conservative.” By contrast, people who pray at least once a day were twice as likely to say they’d refuse to eat GMOs as those who pray less often (38% vs. 18%). 37% of people who call themselves fundamentalists would refuse to eat GMOs, compared to 25% of those who consider themselves religious liberals. Given all that, it isn’t surprising that 40% of those who reject evolution say they are not willing to eat GMOs, compared to 22% of those who accept it.

Anti-GMO sentiment taps into an intuitive uneasiness about the unnatural. There’s something weird and scary about the idea of taking genes from a daffodil and bacteria and jamming it into rice, even if doing so makes the rice more nutritious. That “ick” factor is bipartisan, though there’s research showing that conservatives are more easily disgusted (PDF link), and place greater moral weight on disgust, than liberals. In particular, disgust as a reaction to perceived impurity tends to have the strongest effect on moral judgments; I would expect that to include the impurity of putting foreign DNA in an organism. That link between purity and morality probably explains at least some of the religious correlation, as well as the lack of strong political alignment. It isn’t a leftist war on science. It’s a war between our guts and our brains, and alas, that’s a fight our brains rarely win. With care, though, we can learn to overcome those biases and see the science for what it is, and then use that knowledge to inform the important policy debates ahead.