Dunning-Kruger update – Anti-Vax folks think they know more than doctors

dunning krugerThe term “Dunning-Kruger” is a reference to a cognitive bias. This is where people who know next to nothing on some topic truly believe that the little they do know makes them an expert and grants them the mantle of “expert”. It’s not about bluster or pretense, they truly believe it. In essence, they know so little that they are totally unaware of their degree of utter incompetence. So the context here is anti-vax and a new study, but first let’s explain Dunning-Kruger a bit more.

The name might sound unusual. It comes via two social psychologists David Dunning and Justin Kruger who first described it within a 1999 paper titled “Unskilled and unaware of it: How difficulties in recognizing one’s own incompetence lead to inflated self-assessments.“. There in the abstract they describe it as follows …

People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it.

Since that initial study there have of course been further studies that have added to our understanding. As an addition to that body of knowledge a new study has just been published within Social Science & Medicine.

Let’s dig into that now and see what we discover.

Knowing less but presuming more: Dunning-Kruger effects and the endorsement of anti-vaccine policy attitudes

What did the authors set out to do?

Although the benefits of vaccines are widely recognized by medical experts, public opinion about vaccination policies is mixed. We analyze public opinion about vaccination policies to assess whether Dunning- Kruger effects can help to explain anti-vaccination policy attitudes.


People low in autism awareness – that is, the knowledge of basic facts and dismissal of misinformation about autism – should be the most likely to think that they are better informed than medical experts about the causes of autism (a Dunning-Kruger effect). This “overconfidence” should be associated with decreased support for mandatory vaccination policies and skepticism about the role that medical professionals play in the policy making process.

What did they do to explore this topic?

They conducted a survey that involved 1,310 people. They basically gave them a knowledge test regarding the causes of autism and also measured how confident they felt about their knowledge …

we modeled self-reported overconfidence as a function of responses to a knowledge test about the causes of autism, and the endorsement of misinformation about a link between vaccines and autism. We then modeled anti-vaccination policy support and attitudes toward the role that experts play in the policymaking process as a function of overconfidence and the autism awareness indicators while controlling for potential confounding factors.

What did they find?

More than a third of respondents in our sample thought that they knew as much or more than doctors (36%) and scientists (34%) about the causes of autism.

In one word … “Yikes!”.

Our analysis indicates that this overconfidence is highest among those with low levels of knowledge about the causes of autism and those with high levels of misinformation endorsement. Further, our results suggest that this overconfidence is associated with opposition to mandatory vaccination policy. Overconfidence is also associated with increased support for the role that non- experts (e.g., celebrities) play in the policymaking process.

In other words the conclusion is this. The study demonstrates that those that truly believe that vaccines cause autism also sometimes truly believe themselves to be “experts” and that they have a knowledge on the topic that exceeds that of subject matter experts such as doctors, researchers, or scientists who truly are the subject matter experts.

OK, you can stop reading now. You have a deep knowledge of dunning-kruger and your knowledge on the topic is now way above average. You are an expert.

In reality you are not a social psychologist (and neither am I). We do not have the training, or experience and so “doubt” is your friend. You are probably reading this because you are interested, and rightly so because it is an interesting topic. Being aware that such biases do exist helps us to understand why things are the way they are.

I can predict the following …

  • You have most probably not read that 1999 paper written by Dunning and Kruger (there is a link to it above but you opted to ignore that and have no intention of ever reading it, and that’s fine because you are most probably not a psychology student).
  • You most probably can’t tell me what tests Dunning and Kruger ran and how they reached the conclusion that they did
  • You can’t articulate what other studies have been conducted, or who conducted them, or what they found
  • You can’t articulate or sum up the wider conversation that takes place within the community of social psychologists on the topic.

In other words, while you do now know a little bit, there is a great deal that you simply do not know. I can perhaps go as far as saying that you and I don’t even grasp an understanding of what we don’t yet know – we often don’t actually know what we don’t know.

Facing Reality

Today we live in a world where the idiot-in-chief truly does believe in his own supposedly superior abilities, and yet is so incompetent that he does not grasp how truly incompetent he actually is. Having read this far into this article you can perhaps now understand him a little bit more.

The above is not a political statement that expresses a specific bias, it is an observational fact. You can be a hard-core right-wing Republican and still retain the above conclusion.

In the context of vaccine denial (which to be blunt is really science denial), the idiot-in-chief appointed vaccine denialist Robert Kennedy Jr. to chair an administrative panel on the safety of vaccines. Don’t bother face-palming, others have already done that for you, it’s a well worn road.

When it comes to taking an anti-vax stance, be aware that it is not just Trump or Kennedy …

  • Nearly one in three U.S. adults oppose mandatory vaccine requirements for attending public schools
  • Less than half believe that scientists understand the health effects of the MMR vaccine “very well”

Studies such as this latest one matter because in that context, understanding why it is like this is an important question to ask. It is quite literally a matter of life and death. The question the study explores is not an abstraction but instead is attempting to make sense of why, despite no evidence, there is a thriving anti-vax movement that has traction.

Prior to this study it was thought that there was perhaps a link between Dunning-Kruger effects and anti-vax policy attitudes. What the study does is to demonstrate that this is indeed correct, and so we now have a further insight into understanding why some oppose vaccination policies endorsed by medical professionals.

Public attitudes towards vaccinations are complex and driven by a mix of scientific, psychological, sociocultural, and political factors. So what we learn here is that limited knowledge and misinformation about vaccines play a vital role in public attitudes. The Dunning-Kruger cognitive bias kicks in and the little that is known leads many to believe they know more than the experts.

It’s not that simple

I’m trying to also make sure that as I describe this, it does not itself become too simplistic an answer. There are of course other factors in play …

  • The is a real information defect: U.S. adults are generally uninformed or misinformed about the safety of vaccines, particularly concerning their rumored link to autism. A wide range of sources, internet blogs, celebrity activism, and various media point to this link despite no validated scientific evidence supporting this link.
  • The ease of access to misinformation increases skepticism about science and an outright disregard of scientific evidence. For example, research has shown that misinformation has led to a perception among some that mandatory vaccinations are a result of influence from the pharmaceutical industry and pushed many to pay more attention to the “risks” of vaccines instead of their vital role to public health.
  • The endorsement of anti-vaccine conspiracy theories may also sour public opinion toward vaccine safety and expert research on the subject
  • Individuals who exhibit low levels of generalized interpersonal trust and domain-specific knowledge may be especially likely to endorse conspiracy theories about vaccines.
  • Media consumption habits also likely play a role, with online blogs and other resources influencing the dissemination of anti-vaccine information.
  • Research has also pointed to the roles of ideology, religiosity, and education. For example Republican partisan identification, is associated with increased opposition to vaccines.

What this new study adds to all of the above (and more that I did not mention) is this –

U.S. adults might also endorse anti-vax policy positions because they believe that they are comparatively more knowledgeable than medical experts. These are people who lack the ability to not only judge their own skill, but also struggle to accurately assess the skills of others who might (or might not) be subject matter experts.

Bottom Line – New Insights

People who know the least about the causes of autism and who are misinformed about the link between vaccines and autism  are the most likely to think that they know more than medical professionals about the causes of autism – this is a Dunning Kruger effect.

Additionally, people who think that they know more than medical professionals are less supportive of pro-vaccine policies and more likely to elevate the role that non-experts play in the policymaking process.

In other words, researchers and policymakers interested in increasing support for mandatory vaccination need to combat not only low levels of knowledge and misinformation, but also the independent effect of over- confidence.

Education does matter.

Further Reading


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