Dunning Kruger Effect: You think that you know, but you actually don’t

Boulama K.
by Boulama Kandine
May 05, 2019 — 5 mins read

🗂 Psychology

As we browse through new sources of knowledge every day, and new data generated by the second, our knowledge gets challenged more than ever before.

We tend to fall into three categories when it comes to evaluating our own knowledge on a specific subject:

  • first, we know what we know and are good with it;
  • second, we underestimate our knowledge and skills, always second-guessing our choices and decisions.
  • third, we overestimate our knowledge and tend to be narrow;

In this essay, we will focus on the latter: Overestimating our own knowledge, which is a cognitive bias known as the Dunning Kruger Effect[1].

I have been interested for a while in the brain’s ability to judge its own expertise on various topics, and during my researches, I have been quite impressed by what I found.

It is very interesting to see that social media have shaped the way we think of ourselves on an intellectual standpoint, for the better and, often for the worse.

The Dunning-Kruger effect, or overconfidence effect, is a cognitive bias in which the least qualified individuals in a specific domain of expertise overestimate their competences.

This phenomenon has been demonstrated through a series of experiments led by American psychologists David Dunning and Justin Kruger in the late nineteen-nineties.

During their experiments, the two researchers wanted to challenge the following thesis “Ignorance breeds more self-confidence than knowledge does”, by Charles Darwin. Their first experiment was made on students from Cornell University through various series of tests in reasoning, grammar and humor.

They decided to break their poll of subjects into four types, depending on how they reacted to their incompetence:

  1. the incompetent person that tends to overestimate her/his level of knowledge;
  2. the incompetent person that fails to recognize the competence of those who are truly competent;
  3. the incompetent person that fails to realize his/her degree of incompetence;
  4. if a training of these people leads to a significant improvement of their competence, they will then be able to recognize and accept their previous gaps.

As we may expect, the results were very interesting.

After the experiment, and when the answers were revealed, the subjects were asked to estimate their ranks in relation to the total number of participants. This resulted in a correct estimation by the most competent and an overvaluation by the least competent.

“Through four studies, the authors found that lower-quartile participants for humor, grammar, and logic tests greatly overestimated their performance. While they get the lowest scores, in the 12th percentile, they felt part of the 62nd. “

The Dunning Kruger effect and Social Media

As we have seen in the previous section, people who are more knowledgeable are more likely to correctly judge their knowledge level compared to people less knowledgeable.

By extrapolating this result, we can use that to make a similar study on social medias and how the Dunning Kruger effect affects interactions on social media.

You see, taking the example on Twitter and the interactions that happen on the social platform, many people, with different levels of understandings on various topics interact and give their opinions on such topics — which is great for debates and learning.

However, the problem comes when people with shallow understanding on some complex topic start challenging experts with decades of studies behind them, not for the sake of learning, but for the simple sake of showing that they know.

Dunning-Kruger Effect

Dunning-Kruger Effect

As the chart above shows, as people start learning about a subject, their level of confidence —about their knowledge— skyrockets and as they dig deeper into the given subject, they understand that they do not know much; until they reach the level of expert. Where their level of confidence reaches a maximum but not quite the one reached when they started learning as first.

Aristotle once said,

“The ignorant says the learned doubt, the wise thinking”.

There are dozens of cognitive bias that impede on our social and intellectual development. There are ways to bypass them, but this is not the point of this essay.

Although, we may suffer from each of them from time to time, it is important to be aware of when we feel trapped in any of them, and act on them.

The Dunning Kruger effect, especially, plays an important role on social media, for example where people feel confident enough to challenge highly knowledgeable people on topics that they cannot actually handle.

The problem of this specific bias is that it can give birth to another, very dangerous cognitive bias called the confirmation bias[2] which basically consists in privileging the information confirming its preconceived ideas or its hypotheses (without consideration for the veracity of this information) and granting less weight to the hypotheses and information playing against its conception. This can lead to the spread of fake news, and much worse.

Where should we go from here?

The obvious thing to do here is to call-out people on their unfounded assumptions, however it seems like a very easy solution for a quite complex problem. But as stated in the previous paragraph, the first thing is that people who tend to fall for these biases (the Dunning Kruger effect and confirmation bias) is to acknowledge their lack of understanding of a topic and be open to more opinions; because this, too is one of the igniter of those biases that pollute social media platforms such as Twitter.


[1] Kruger, J., & Dunning, D. (1999). Unskilled and unaware of it: How difficulties in recognizing one’s own incompetence lead to inflated self-assessments.Journal of Personality and Social Psychology, 77(6), 1121-1134. http://dx.doi.org/10.1037/0022-3514.77.6.1121

[2] Wikipedia contributors. (2019, April 27). Confirmation bias. InWikipedia, The Free Encyclopedia. Retrieved 11:20, May 5, 2019, from https://en.wikipedia.org/w/index.php?title=Confirmation_bias&oldid=894450038

Atir, S., Rosenzweig, E., & Dunning, D. (2015). When knowledge knows no bounds: Self-perceived expertise predicts claims of impossible knowledgePsychological Science26(8), 1295-1303.


Cover: Photo by Mathew Schwartz on Unsplash

Chart: Catalogue of Bias.

🏷 Tags

Psychological Biases