Rejecting scientific consensus and the illusion of understanding

Here I discuss a paper in Science by Nicolas Light et al. (2022). The article shows that people who disagree most with the scientific consensus on topics such as climate change, vaccination and evolution have less knowledge about these topics than people who believe in the scientific consensus but they think they know more about it. They have an illusion of understanding. 

Scientific consensus 

Within science, there are countless topics about which researchers still lack knowledge and disagree with each other. But there are also a number of topics on which the amount of evidence is so vast and consistent that there is great consensus among scientists. Examples include that evolution of species (including humans) exists, that genetically modified foods are safe to eat, that human activities are warming the planet, that vaccines are effective at containing the coronavirus, and so on. 

Scientific consensus deniers 

On these and other points of scientific consensus, there are social movements that dispute their truth. This includes some famous people but unfortunately also many unknown people. The consequences of denying scientific knowledge can be serious: malnutrition, financial disadvantage, illness and death. 

Paper in Science 

Light et al. did 5 studies. In Studies 1 to 3, they examined seven controversial issues on which there is substantial scientific consensus: climate change, genetically modified foods, vaccination, nuclear energy, homeopathic medicine, evolution and the big bang theory. In Studies 4 and 5, they examined attitudes towards COVID-19. 
The results of five studies showed that the people who most disagree with the scientific consensus know less about the relevant topics than people who believe the scientific consensus but think they know more. In other words, they have high subjective knowledge (this is your own judgment of how much you know) but low objective knowledge (this is how much you actually know). This phenomenon is quite common, although relations were weaker on some more polarized issues, especially climate change. 

Simplistic explanations 

The researchers also found that the more participants rejected the scientific consensus, the greater the difference between subjective and objective knowledge. What, then, is this great confidence of these people based on? They may well understand a simple explanation but that it is simplistic and does not correspond to the much more complex scientifically established facts. They have an illusion of understanding.