Why do so many people oppose genetically modified organisms, or GMOs?
According to a new paper forthcoming in the journal Trends in Plant Science, it's because opposition to GMOs taps into deep cognitive biases. These biases conspire to make arguments against GMOs intuitive and compelling, whether or not they're backed by strong evidence.
The authors of the paper — a mix of philosophers and biologists — turn to research in the cognitive sciences to shed light on the mismatch between the public's perception of GMOs (which is fairly negative, especially in Europe) and the state of the evidence about their safety (which is fairly positive). They identify a handful of psychological tendencies and preferences that can help explain what they refer to in the title of their paper as "the intuitive appeal of GMO opposition." Some messages about GMOs — whether they come from scientists, the media, lobbyists or politicians — can resonate and play a large role in shaping public opinion, while others simply fall flat.
What do these psychological tendencies and preferences look like? I'll mention two: psychological essentialism and a preference for the "natural."
When it comes to biological organisms, psychological essentialism refers to the tendency to think of species as being defined by some underlying essence that makes an individual the kind of organism that it is, and that gives rise to its core properties, such as what it looks like and how it tastes. Essentialist biases are one reason people have a hard time wrapping their heads around human evolution. Natural selection requires variation within a species (that's what fuels differential reproduction!), whereas a shared essence highlights what's common across individuals of a species, not how they differ. Moreover, the idea of common descent implies that new species can gradually evolve from earlier species, which challenges the idea that species boundaries are clear-cut, with each species corresponding to a unique essence.
When it comes to GMOs, essentialist beliefs arise in a few forms. One recent paper reported greater opposition to transgenic modifications (which involve crossing species boundaries) than to cisgentic modifications (within the same species), mirroring people's greater resistance to macroevolution (which crosses putative "essence" boundaries) than to microevolution (which does not). Another study found that most Americans believe that tomatoes with catfish genes would taste "fishy," mirroring other domains in which essentialist beliefs lead to inaccurate views about transmission. For instance, some people believe that the recipient of an organ transplant could acquire the personal characteristics of the donor, potentially because they believe that some of the donor's essence is transmitted along with the organ.
A second factor underlying the intuitive distrust of GMOs is people's preference for the "natural," though pinning down precisely what that means is its own challenge. A 2012 article on European and American beliefs about the meaning of "natural" found that for many people it's defined by negation: When it comes to food, the natural is that which does not involve additives, processing or human intervention. Consistent with these ideas, a study published in 2014 found that genetic hybrids were judged more negatively when they came about via genetic modification than via natural procreation, even when the gene combinations themselves were the same. Cisgenic modification was also judged more natural than transgenic modification, though neither was judged favorably by most respondents.
Recognizing that human psychology plays a role in the distrust of GMOs isn't new (Maria Konnikova wrote an excellent post on the topic for the New Yorker in 2013), but the forthcoming paper in Trends in Plant Sciences does a nice job summarizing some of the psychological processes at work in people's (mis)perceptions of GMOs, and invites a fresh conversation about how scientists, policy makers and the public can best come together around these issues.
Of course, understanding the psychology of GMOs doesn't tell us whether GMOs are truly safe, or about their economic, legal and social consequences. Those are questions for biologists, economists, legal scholars and ethicists, not (just) for cognitive scientists studying the human mind. But identifying the role of cognitive processes in the perception of GMOs can shed light on why discussions of GMOs often take the forms they do. And, just maybe, a more critical attitude toward why we do — and don't — find some ideas intuitive or compelling can help us change the conversation from one that's grounded in gut feelings about what's "natural" or "right" to one that's grounded in scientific evidence and constructive argumentation.
Tania Lombrozo is a psychology professor at the University of California, Berkeley. She writes about psychology, cognitive science and philosophy, with occasional forays into parenting and veganism. You can keep up with more of what she is thinking on Twitter: @TaniaLombrozo.