When researchers asked 500 Americans how they feel about foods that contain genetically modified organisms (GMOs), everybody expected the results to be spicy — but they were even more interesting than that.

There were two main findings in the study. The first one was expected, although not encouraging: 90% of participants oppose foods containing GMOs, which is in conflict with a strong scientific consensus — almost 90% of scientists believe GMOs are safe and can be of great benefit to human society. The second finding, however, was even starker.

Researchers also asked participants how well they think they are informed on the matter. Those who opposed GMOs the most believed they knew the most about the topic. Yet, when they were given an actual scientific test, they scored the lowest.

“There is widespread agreement among scientists that genetically modified foods are safe to consume and have the potential to provide substantial benefits to humankind. However, many people still harbor concerns about them or oppose their use,” researchers write in the study.

“Similar results were obtained in a parallel study with representative samples from the United States, France and Germany,” they add.

This belief, that one knows very much about the topic (even more than an expert) is remarkably widespread — even when this is clearly not the case. Scientists call it the Dunning–Kruger effect.

The effect was described in a 1999 seminal paper aptly called “Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments”. The paper drew inspiration from the case of a criminal called McArthur Wheeler who robbed banks while his face was covered with lemon juice — something he believed would make it invisible to the surveillance cameras (based on his misunderstanding of how lemon juice can be used as invisible ink).

But the Dunning–Kruger effect shows up in much more familiar situations. In team sports and computer games, players are often inclined to see defeats as caused by their teammates while also ignoring their own shortcomings. More importantly, the “we know better than experts” mindsets often appear in science and politics. In the UK, much about the Brexit debate focused on ignoring expert analysis and prognosis. “Britain has had enough of experts,” prominent pro-Brexit politicians often said.

Research has previously shown that this type of overconfidence is often associated with anti-vaccine attitudes and a propensity to vote in non-experts as policymakers. We’re seeing the effects of the Dunning-Kruger effect more and more in society, and the effects are concerning.

It’s important for researchers to be aware that the public analyzes information in a different way than scientists and look for optimized communication strategies. Otherwise, the gap between the scientific consensus and the popular belief can grow more and more.

There was an intriguing exception, however. This pattern did not emerge for attitudes and beliefs about climate change, researchers report.

The study was published in Nature Human Behavior.