Dunning-Kruger: Cognitive Bias, Illusory Superiority and the Knowledge Illusion

The Dunning Kruger Effect is a psychological phenomenon first identified in a 1999 study by U.S. psychologists David Dunning, then of Cornell, and Justin Kruger of University of Illinois who discovered that people with relatively low ability and levels of knowledge tend to systematically overestimate their own abilities. The competence of other people is, by contrast, always underestimated. It basically describes “ignorance about ignorance,” a very wide-spread human characteristic.

After all, Danning and Kruger’s study earned them the satirical Ig Nobel Prize in 2000 – an award given for research that makes people laugh, then think – and the effect named after them had at least a career in popular psychology. However, Dunning-Kruger has also been used in connection with climate change deniers who, due to a particular cognitive defect regarding scientific evidence, would rather distrust all data on global warming.

Now, in a survey of 2,500 Europeans and U.S. citizens, researchers led by Philip Fernbach (Leeds School of Business at the University of Colorado, Boulder) encountered this phenomenon again, this time in connection with green genetic engineering. For their study in Nature Human Behavior, psychologists and marketing researchers first ascertained how well the subjects rated their own knowledge on the subject. In the second part, they then tested knowledge in genetics to determine how much their test persons did, in fact, know.

In addition, study participants were asked about their attitude to genetically modified organisms. Although there is widespread consensus among researchers that genetically modified food is safe for human consumption and theoretically even has potential to provide some health benefits, over 90 percent of respondents rejected genetically modified food. This has long turned into a cultural war.

But that was not the most important result of the study. That honor belongs to a paradoxical nexus: those who are particularly opposed to genetically modified food also said that they knew a lot about the subject. At the same time, they performed worst on knowledge tests about genetics in particular and science in general – a poster version of the Dunning-Kruger effect: the knowledge illusion, or illusory superiority.

In the words of first author Philip Fernbach, "Extreme views often stem from people who feel they understand complex topics better than they do." One possible self-reinforcing consequence of the phenomenon is that those with the least knowledge of important scientific subjects will most likely remain ignorant – simply because they are “knowledge-resistant,” not open to new knowledge. And, of course, they will not look it up because they think they already know everything in the first place.

So the key question is how to make people "appreciate what they do not know," as study co-author Nicholas Light says. But that also means rethinking previous approaches to science communication. Mere information and an appeal to trust science and its kind of cognitive production will no longer reach this group of radical opponents of genetic engineering. 

The study’s authors also looked at other topics such as gene therapy and climate change. While the attitude towards gene therapy and knowledge about it show very similar patterns to genetic engineering, the findings about climate change deniers differed: remarkably, unlike in the study about genetics, the Dunning-Kruger effect does not seem to apply there. Rather, political polarization and group membership appears to shape people's attitude to climate change considerably more than knowledge (or lack thereof). Just like science itself is busy seeking to build resistance to climate change, human nature, in its political incarnation, may be inclined to favor resistance to science.