People with the greatest opposition to the scientific consensus tend to have the lowest levels of objective science knowledge but the highest levels of self-rated knowledge, according to new research published in Science Advances. The findings are in line with the Dunning-Kruger effect, a well-documented phenomenon in which people who are lacking in skills or knowledge tend to overestimate their abilities.
“I am interested in the public’s understanding of science because it is hugely important for societal and environmental wellbeing,” said study author Nick Light, an assistant professor of marketing at Portland State University. “When people act in ways that go against good science, people get sick, lose their homes, lose money, are displaced, or even die (as is the case with COVID, natural disasters, etc.). The better we can understand why people hold attitudes that run counter to scientific consensus, the better scientists or policymakers can design interventions to help people.”
In two initial studies, which included 3,249 U.S. adults recruited from Amazon Mechanical Turk and Prolific Academic, participants were randomly assigned to indicate their level of support or opposition to one of seven scientific issues: climate change, genetically-modified foods, nuclear power, vaccination, evolution, the Big Bang, or homeopathic medicine. The participants were asked to rate their understanding of the topic on a 7-point scale, ranging from “Vague understanding” to “Thorough understanding.”
To assess their scientific knowledge, the participants then responded to 34 randomly ordered true-false questions. The questions included a broad range of scientific topics, including “True or false? The center of the earth is very hot,” “True or false? All insects have eight legs,” and “True or false? Venus is the closest planet to the sun.”
Light and his research team found that people who were more opposed to the scientific consensus on their given topic were more likely to claim to have a “thorough understanding” of it. But those who were more opposed to the scientific consensus tended to score worse on the test of objective science knowledge.
“Scientists are constantly debating the best ways to explain the world around us,” Light told PsyPost. “Sometimes, however, the evidence is so strong or consistent that most of them agree on something. That’s what we call scientific consensus. In this paper we find that the people who have attitudes that are more extremely against the scientific consensus think they know the most about the scientific issues, but actually know the least.”
The researchers also found some evidence that political polarization could weaken these relationships. For more politically polarized issues, the relationship between opposition to the scientific consensus and objective knowledge was not quite as negative.
“The main caveat is that although this pattern of effects appears to be fairly general, we don’t find it for all issues,” Light said. “One notable example is climate change. Our next steps include really digging deeper into the psychology to try to figure out why we don’t find these effects for some issues.”
In a third study, which included 1,173 U.S. adults, the participants were given the opportunity to bet on their ability to score above average on the test of objective science knowledge. In line with the previous studies, Light and his colleagues found that participants with greater opposition to the scientific consensus tended to earn less due to knowledge overconfidence.
In a fourth study, which included 501 participants, the researchers examined whether knowledge overconfidence was related to the willingness to receive a COVID-19 vaccine. The study was conducted in July 2020, before a vaccine was publicly available. The participants were asked their willingness to receive a vaccination in the future and then rated their understanding of how a COVID-19 vaccine would work.
The participants then completed a 23-question test of scientific knowledge, which included six items about COVID-19, such as “True or false? COVID-19 is a kind of bacteria” and “True or false? COVID-19 can be transmitted through houseflies.”
Light and his colleagues found that participants who were more opposed to receiving a vaccine tended to report having a greater understanding of how a COVID-19 vaccine would work, but their general knowledge of science and COVID-19 tended to be worse.
A fifth study of 695 participants, conducted in September 2020, found a similar pattern of results regarding COVID-19 mitigation policies. The results held even after controlling for political identity.
The researchers said the findings have some practical implications for science communicators and policymakers.
“Given that the most extreme opponents of the scientific consensus tend to be those who are most overconfident in their knowledge, fact-based educational interventions are less likely to be effective for this audience,” Light and his colleagues wrote. “For instance, The Ad Council conducted one of the largest public education campaigns in history in an effort to convince people to get the COVID-19 vaccine. If individuals who hold strong antivaccine beliefs already think that they know all there is to know about vaccination and COVID-19, then the campaign is unlikely to persuade them.”
The study, “Knowledge overconfidence is associated with anti-consensus views on controversial scientific issues“, was authored by Nicholas Light, Philip M. Fernbach, Nathaniel Rabb, Mugur V. Geana, and Steven A. Sloman.