Aug 13 2018

Dunning Kruger Effect and Anti-Vaccine Attitudes

One of the persistent themes of this blog is that expertise matters. This is not to say the experts are always right (sometimes they disagree with each-other), and there is also a range of expertise, and different kinds of experts can have different biases and blind spots. But all things considered, someone who has formal expertise on a specific topic is likely to know much more about that topic than someone who has read about it on the internet.

Further, most people underestimate the amount of knowledge that exists on a topic, and therefore the vast gulf of knowledge that exists between them and the experts. In fact, the more someone knows about a topic the more they understand how much is known, and the more humble they tend to be with respect to their own knowledge. The flip side of this – people who know little tend to overestimate their relative knowledge – is an established psychological phenomenon known as the Dunning-Kruger effect.

Operationally Dunning and Kruger found in their study that the lower someone performed on a test of knowledge, the greater the gap between their perceived knowledge and performance and their actual performance. At around the 80th percentile and above, people tend to underestimate their relative knowledge. Below that point they tend to increasingly overestimate it, and everyone thinks they are above 50%.

In a later paper Dunning explores this phenomenon further:

An ignorant mind is precisely not a spotless, empty vessel, but one that’s filled with the clutter of irrelevant or misleading life experiences, theories, facts, intuitions, strategies, algorithms, heuristics, metaphors, and hunches that regrettably have the look and feel of useful and accurate knowledge.

What he is saying is that the DK effect is not just a manifestation of people not knowing how much knowledge they don’t know, they also have the illusion of knowledge from every day experiences and flawed intuition (in the relative absence of formal teaching).

But there is yet another layer here. In addition to lack of perspective from knowledge, and the illusion of knowledge from casual sources, there is also pseudo-formal knowledge in the form of conspiracy theories, alternative sources, and pseudo-experts. These sources can create a much more powerful illusion of knowledge, combined with a specific lack of respect for expertise itself as well as specific expert institutions. Fueled by these sources of information, people can be made to feel they actually know more than the “compromised” experts.

A new study demonstrates this extension of the DK effect.

Researchers gave 1300 Americans a questionnaire testing their knowledge and attitudes towards vaccines and autism. They found:

We found that 34 percent of U.S. adults in our sample feel that they know as much or more than scientists about the causes of autism. Slightly more, or 36 percent, feel the same way about their knowledge relative to that of medical doctors.

We also found strong evidence of Dunning-Kruger effects in our sample. Sixty-two percent of those who performed worst on our autism knowledge test believe that they know as much or more than both doctors and scientists about the causes of autism, compared to only 15 percent of those scoring best on the knowledge test. Likewise, 71 percent of those who strongly endorse misinformation about the link between vaccines and autism feel that they know as much or more than medical doctors about the causes of autism, compared to only 28 percent of those who most strongly reject that misinformation.

As much of a jaded skeptic as I am, I was still a little surprised to find that 34-36% of adults thought they knew as much or more than doctors and scientists about autism. Wow. I was not surprised by the effect, just its magnitude. A third of the general public actually have the hubris to think their common knowledge is equal to or greater than experts who have dedicated years to formal study.

The second paragraph makes sense, and is classic DK effect – those with the least amount of knowledge had the highest chance of thinking they knew more than the experts. But this effect also tracks with anti-vaccine attitudes, which is a big clue that this lack of respect for expertise is part of the anti-vaccine movement.

I do see this in part as a struggle between competing ideas. Narratives do compete in the marketplace. What appears to have happened is that unscientific alternative narratives struggling to spread through the population found the most fertile ground in those with the least scientific knowledge. But such unscientific ideas still bumped up against expert opinion – even among the general population, people tend to listen to scientists and experts over some random guy.

To further the penetration of these unscientific narratives, it became necessary to attack the experts and their institutions, and even the concept of expertise itself. This was a preemptive strike, and it has, unfortunately, had an effect. This was not caused by the internet, but it was facilitated by it. It became easier to create the trappings of knowledge online, where brick-and-mortar institutions, tested by time, were not necessary.

The conspiracy theory is also perfectly suited to this task – those experts are all part of some deep conspiracy by the elites. They can’t be trusted. But in their place was substituted alternative experts, health gurus and celebrity conspiracy theorists. On the political right, the government is the chief architect of the conspiracies. On the left, it is corporations – although they meet at the extremes, as corporate power allegedly captures government power.

Into the mix also comes con-artists and opportunists. The death of expertise is their dream, because they can thrive in a world where formal knowledge, standards, and regulations are trumped by a slick narrative.

The anti-vaccine movement as a whole is a nice demonstration of all of this – distrust of the government and corporations, distrust of medical doctors and scientists, distrust of expertise itself, and the elevation of pseudoknowledge from dedicated anti-vaccine sources, celebrities, conspiracy theorists, and con-artists with something to sell.

If, however, you want a demonstration of how powerful all of this can be, look no further than the flat-earthers. So far, in my opinion, that is the ultimate manifestation of the DK effect combined with a massive conspiracy theory destroying not only respect for knowledge and expertise, but even common sense.

The good news is that the DK effect does suggest one partial solution – education. The DK effect strongly implies that knowledge in a particular area does result in humility and perspective. Scientific literacy does protect, to some extent, against believing in nonsense. But scientific literacy is not enough, we also need to teach critical thinking skills, which obviously should include some basic understanding of the nature of expertise, and the magnitude of expert knowledge that actually exists.

This is why I encourage everyone to become as much of an expert as possible in one area, no matter how narrow or whimsical. It doesn’t have to be part of your job or career, and can be just a hobby. Any expertise then gives a little window into the DK effect, because it will give you insight into the gulf of knowledge between the average person and an expert. Then all you have to do is apply that perspective to every other area of knowledge.

It is also critical to understand that the DK effect applies to all of us – to everyone. We all have areas of relative lack of knowledge, and will tend to overestimate our knowledge in those areas – unless we have specific understanding of the DK effect and guard against it.

Like this post? Share it!

No responses yet