Dunning Kruger Effect explained

Dunning Kruger Effect - Toolshero

Dunning Kruger effect: This article explains the Dunning Kruger effect in a practical way. After reading it, you will understand the basics of this powerful psychology tool.

What is the Dunning Kruger effect? The explanation

The Dunning Kruger effect is a cognitive bias, in which incompetent people tend to overestimate their ability.

The opposite effect for competent persons has also been studied: the tendency to underestimate their skills. An example of this is that one person in class who always says that he expects to fail after an exam. And yet he scores a 9.

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The Dunning Kruger effect can be measured by comparing self-evaluation with objective performance. For example, people who participate in such a survey take a quiz and are then asked to estimate how well they have performed. This subjective assessment of the participants themselves is then compared with the actual score they have obtained.

This comparison is done in both relative and absolute terms. That is, compared to a peer group as the percentage that performed better, or compared to objective measures such as the number of questions answered correctly.


The effect is usually explained in terms of metacognitive skills. The explanation is based on the idea that incompetent people do not have the ability to distinguish between good and bad performance. They tend to overestimate themselves because they fail to see the qualitative difference between their performance and the performance of others.

This is also known as the dual burden account. The lack of this ability is accompanied by the ignorance of this lack. In some studies, the metacognition aspect has been included as part of the definition of the Dunning Kruger effect. Other studies see it more as an explanation that should be seen as separate from the definition.

The effect itself has been investigated by researchers David Dunning and Justin Kruger. They were the two social psychologists who first described the phenomenon. A total of four studies focused on the effect.

The Dunning Kruger Effect - Toolshero

Figure 1 – the Dunning Kruger Effect

Criticism of the Dunning Kruger effect

It is important to note that there is much criticism on the description of this phenomenon. Many debates on the concept focus on the metacognitive explanation and omit the empirical findings.

The most important argument heard in this category is the statistical explanation, which states that the effect is mainly a statistical artifact due to the regression to the mean combined with another cognitive bias. This bias is also known as the better-than-average effect.

The Dunning Kruger effect is described as being relevant for various purposes and practicalities, but there is disagreement about its use too. For example, inaccurate self-esteem could lead people to make poor decisions. It can also prevent people from addressing and improving their own shortcomings.

In some cases, this form of overconfidence can have positive side effects, such as increased motivation and energy.

Example of the Dunning Kruger effect in everyday life

The phenomenon of overestimation and misjudgment of one’s own competences is something that can often be seen in daily life. Competent people are by definition more aware of this than incompetent people.

An example of the effect is that one family member at the dining table during a vacation dinner. The member of the family speaks at length and passionately on a subject and proclaims to everyone that their view is wrong. Although it is clear to many people at the table that this family member has no idea what he is talking about, he continues to chatter and is oblivious to his own ignorance.

Research by Dunning and Kruger

In one of the studies, the researchers asked 65 participants to rate how funny certain jokes were. Some participants were exceptionally bad at judging and predicting what jokes others would find funny, but described themselves as being highly humorous.

Incompetent people, the researchers argued, not only perform poorly, but they are also incapable of assessing the quality of their own output. That could be the reason why students who score poorly on exams sometimes feel they deserve a higher score. They then clearly overestimate their own knowledge and cannot accurately assess their own performance.

Incompetent people are also unable to recognize the skills of others. That is part of the reason why they see themselves as much smarter and more capable than others.

Notable effect on behavior and self-confidence

Still, the incompetence doesn’t leave people disoriented or cautious, study researcher David Dunning wrote in an article for the Pacific Standard. Instead, incompetent people are often blessed with an inappropriate confidence, bolstered by what feels like deep knowledge about many things to them.

On the other hand, it can have a profound effect on what people believe. In one of the studies by researchers Dunning and Eherlinger, it was found that women performed just as well in a scientific quiz as men. Yet the women underestimated their achievements because they assumed that they have less scientific reasoning skills than men.

Faith is also part of this phenomenon. Some women refuse to participate in competition because of their religious beliefs.

But why does this phenomenon even exist?

Dunning and Kruger suggested, as indicated earlier, that it arises from ‘dual burdens’. Not only are people incompetent, but this incompetence robs them of the ability to realize how incompetent they are.

Incompetent people tend to:

  • Overestimate their own skills and achievements
  • Not recognizing skills and knowledge of others
  • Not recognizing own mistakes and lack of insight

The traits a person needs to determine how good their own performance is are the same traits needed to judge how others are doing. So if someone lacks the capacity to judge themselves, then they remain incompetent and also ignorant of their own inability.


This inability has everything to do with metacognition, or rather, the lack of metacognition. Metacognition is about thinking about one’s own thinking. People sometimes look at themselves from a limited and subjective angle. From this incomplete or erroneous perspective, they appear highly competent and knowledgeable, sometimes even superior to others. This makes it almost impossible to paint a realistic picture of yourself.

A little knowledge

Another factor that can be a reason for the Dunning Kruger effect is having a little bit of knowledge. Having a little bit of knowledge about a particular subject can lead that person to think they know everything there is to know. A little knowledge can therefore be dangerous.

The difference is that a competent person knows when the knowledge he or she has is no longer sufficient in a conversation or other social situation. This person then stops talking. An incompetent person will still continue to share ideas and comments of which they are not at all sure if they have any connection with the truth.

Other explanations

There are a number of factors that can also contribute to the Dunning Kruger effect. These are:

  • Using mental shortcuts that allow people to make quick decisions
  • The tendency to look for patterns in things, even when there aren’t any
  • The tendency of the human mind to try to organize and understand the information that comes in. The average person processes an enormous amount of information these days and it is not surprising that sometimes the mark is missed

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Now it’s your turn

What do you think? Do you recognize the explanation about the Dunning Kruger effect? Do you overestimate your own skills? Or those of others? What other related methods or theories do you know? Do you have any tips or comments?

Share your experience and knowledge in the comments box below.

More information

  1. Mazor, M., & Fleming, S. M. (2021). The Dunning-Kruger effect revisited. Nature Human Behaviour, 5(6), 677-678.
  2. Mahmood, K. (2016). Do people overestimate their information literacy skills? A systematic review of empirical evidence on the Dunning-Kruger effect. Communications in Information Literacy, 10(2), 3.
  3. Schlösser, T., Dunning, D., Johnson, K. L., & Kruger, J. (2013). How unaware are the unskilled? Empirical tests of the “signal extraction” counterexplanation for the Dunning–Kruger effect in self-evaluation of performance. Journal of Economic Psychology, 39, 85-100.
  4. Dunning, D. (2011). The Dunning–Kruger effect: On being ignorant of one’s own ignorance. In Advances in experimental social psychology (Vol. 44, pp. 247-296). Academic Press.

How to cite this article:
Janse, B. (2022). Dunning Kruger Effect. Retrieved [insert date] from Toolshero: https://www.toolshero.com/psychology/dunning-kruger-effect/

Original publication date: 11/14/2022 | Last update: 08/22/2023

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Ben Janse
Article by:

Ben Janse

Ben Janse is a young professional working at ToolsHero as Content Manager. He is also an International Business student at Rotterdam Business School where he focusses on analyzing and developing management models. Thanks to his theoretical and practical knowledge, he knows how to distinguish main- and side issues and to make the essence of each article clearly visible.


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