What Is the Dunning-Kruger Effect?

A cognitive bias that causes an overestimation of capability

The Dunning-Kruger Effect

Verywell / Bailey Mariner

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Dunning-Kruger Effect

The Dunning-Kruger effect is a type of cognitive bias in which people believe they are smarter and more capable than they are. Essentially, low-ability people do not possess the skills needed to recognize their own incompetence. The combination of poor self-awareness and low cognitive ability leads them to overestimate their capabilities.

The term lends a scientific name and explanation to a problem that many people immediately recognize—that fools are blind to their own foolishness. As Charles Darwin wrote in his book The Descent of Man, "Ignorance more frequently begets confidence than does knowledge."

This article explores how the Dunning-Kruger effects works, the history of research on this phenomenon, and why people may overestimate their skills. It also covers some of the ways you can avoid overestimating your knowledge.

What Is the Dunning-Kruger Effect?

This phenomenon is something you may have experienced in real life. An example of the Dunning-Kruger effect is a situation that many have perhaps experienced around the dinner table at a holiday family gathering.

Throughout the meal, a member of your extended family spouts off on a topic at length, boldly proclaiming that they are correct and that everyone else's opinion is stupid, uninformed, and just plain wrong. While it may be evident that this person has no idea what they are talking about, they prattle on, blithely oblivious to their ignorance.

The effect is named after researchers David Dunning and Justin Kruger, the two social psychologists who first described it. They performed a series of four investigations in their original study on this psychological phenomenon.

People who scored in the lowest percentiles on grammar, humor, and logic tests also tended to dramatically overestimate how well they had performed (their actual test scores placed them in the 12th percentile, but they estimated that their performance placed them in the 62nd percentile).

The Research

In one experiment, for example, Dunning and Kruger asked their 65 participants to rate how funny different jokes were. Some participants were exceptionally poor at determining what other people would find funny—yet these subjects described themselves as excellent judges of humor.

Incompetent people, the researchers suggested, were not only poor performers but were also unable to accurately assess and recognize the quality of their work. This is perhaps why students who earn failing scores on exams sometimes feel they deserve a much higher score. They overestimate their knowledge and ability and cannot accurately assess their performance.

Low performers are unable to recognize the skill and competence levels of other people, which is part of the reason why they consistently view themselves as better, more capable, and more knowledgeable than others.

"In many cases, incompetence does not leave people disoriented, perplexed, or cautious," wrote David Dunning in an article for Pacific Standard. "Instead, the incompetent are often blessed with an inappropriate confidence, buoyed by something that feels to them like knowledge."

Effects on Behavior and Decisions

This effect can have a profound impact on what people believe, the decisions they make, and the actions they take.

In one study, Dunning and Ehrlinger found that women performed equally to men on a science quiz, and yet women underestimated their performance because they believed they had less scientific reasoning ability than men. The researchers also found that these women were more likely to refuse to enter a science competition due to this belief.

Dunning and his colleagues have also performed experiments in which they ask respondents if they are familiar with various terms related to subjects including politics, biology, physics, and geography. Along with genuine subject-relevant concepts, they interjected completely made-up terms.

In one such study, approximately 90% of respondents claimed they had at least some knowledge of the made-up terms. Consistent with other findings related to the Dunning-Kruger effect, the more familiar participants claimed that they were with a topic, the more likely they were to also claim they were familiar with the meaningless terms.

Why It Happens

So what explains this psychological effect? Are some people simply too dense to recognize it? Dunning and Kruger suggest that this phenomenon stems from what they refer to as a "dual burden." People are not only incompetent; their incompetence robs them of the mental ability to realize just how inept they are.

Incompetent people tend to:

  • Overestimate their skill levels
  • Fail to recognize the genuine skill and expertise of other people
  • Fail to recognize their own mistakes and lack of skill

The very knowledge and skills necessary to be good at a task are the same qualities that a person needs to recognize that they are not good at that task. So if a person lacks those abilities, they remain not only bad at that task but ignorant of their inability.

This effect has been attributed to a number of different explanations, including:

An Inability to Recognize Lack of Skill and Mistakes

Dunning suggests that deficits in skill and expertise create a two-pronged problem. First, these deficits cause people to perform poorly in the domain in which they are incompetent. Secondly, their erroneous and deficient knowledge makes them unable to recognize their mistakes.

A Lack of Metacognition

The Dunning-Kruger effect is also related to difficulties with metacognition. Metacognition refers to the ability to step back and look at one's behavior and abilities from outside of oneself.

People can often only evaluate themselves from their own limited and highly subjective point of view. From this limited perspective, they seem highly skilled, knowledgeable, and superior to others. Because of this, people sometimes struggle to have a more realistic view of their abilities.

A Little Knowledge Can Lead to Overconfidence

Another contributing factor is that sometimes a tiny bit of knowledge on a subject can lead people to mistakenly believe that they know all there is to know about it. As the old saying goes, a little bit of knowledge can be a dangerous thing.

A person might have the slimmest bit of awareness about a subject, yet thanks to the Dunning-Kruger effect, believe that they are an expert.

Other factors that can contribute to the effect include:

  • The use of heuristics, or mental shortcuts that allow people to make decisions quickly
  • A tendency to seek out patterns even where none exist

Our minds are primed to try to make sense of the disparate array of information we deal with daily. As we try to cut through the confusion and interpret our abilities and performance within our worlds, it is perhaps not surprising that we sometimes fail so completely to judge how well we do accurately.

Are You Less Competent Than You Think?

So who is affected by the Dunning-Kruger effect? According to the researchers, everyone is prone to this effect. This is because no matter how informed or experienced we are, everyone has areas in which they are uninformed and incompetent. You might be smart and skilled in many areas, but no one is an expert at everything.

The reality is that everyone is susceptible to this phenomenon, and most of us probably experience it with surprising regularity. People who are genuine experts in one area may mistakenly believe that their intelligence and knowledge carry over into other areas in which they are less familiar.

A brilliant scientist, for example, might be a very poor writer. For the scientist to recognize their lack of skill, they need to possess a good working knowledge of grammar, composition, and other elements of writing. Because those are lacking, the scientist in this example also lacks the ability to recognize their own poor performance.

Recap

The Dunning-Kruger effect is not synonymous with low IQ. As awareness of the term has increased, its misapplication as a synonym for "stupid" has also grown. It is, after all, easy to judge others and believe that such things simply do not apply to you.

Is the Dunning-Kruger Effect Real?

Not everyone agrees that the Dunning-Kruger effect actually exists, however. Instead, some critics have suggested that the effect is instead a data artifact. In mathematical studies, researchers were able to replicate the effect using computer-generated random data. Such studies found that experts and amateurs overestimate or underestimate their abilities at about the same rate. 

The research did find, however, that experts tend to be better at assessing their own abilities and that women generally make more accurate self-assessments than men.

Dunning-Kruger Effect vs. Imposter Syndrome

So if the incompetent tend to think they are experts, what do genuine experts think of their own abilities? Dunning and Kruger found that those at the high end of the competence spectrum did hold more realistic views of their own knowledge and capabilities. However, these experts actually tended to underestimate their own abilities relative to how others did.

Top-scoring individuals know that they are better than the average, but they are not convinced of how superior their performance is to others. The problem, in this case, is not that experts don't know how well-informed they are; they tend to believe that everyone else is also knowledgeable.

This can sometimes lead to the opposite of the Dunning-Kruger effect—imposter syndrome. Since the Dunning-Kruger effect involves overconfidence in one's abilities, the opposing tendency would involve underconfidence in one's abilities. In imposter syndrome, competent people doubt their own abilities and fear that others will discover them to be frauds.

How to Overcome the Dunning-Kruger Effect

So is there anything that can minimize this phenomenon? Is there a point at which the incompetent actually recognize their own ineptitude?

"We are all engines of misbelief," Dunning has suggested. While we are all prone to experiencing the Dunning-Kruger effect, learning more about how the mind works and the mistakes we are all susceptible to might be one step toward correcting such patterns.

As people learn more about the topic of interest, they begin to recognize their lack of knowledge and ability. Then as people gain more information and become experts on a topic, their confidence levels begin to improve again.

So what can you do to gain a more realistic assessment of your abilities in a particular area if you are not sure you can trust your self-assessment?

  • Keep learning and practicing. Instead of assuming you know all there is to know about a subject, keep digging deeper. Once you gain greater knowledge of a topic, you will likely recognize how much there is still to learn. This can combat the tendency to assume you’re an expert, even if you're not.
  • Ask other people how you're doing. Another effective strategy involves asking others for constructive criticism. While it can sometimes be difficult to hear, such feedback can provide valuable insights into how others perceive your abilities.
  • Question what you know. Even as you learn more and get feedback, it can be easy to only pay attention to things that confirm what you think you already know. This is an example of another type of psychological bias known as the confirmation bias. In order to minimize this tendency, keep challenging your beliefs and expectations. Seek out information that challenges your ideas.

A Word From Verywell

The Dunning-Kruger effect is one of many cognitive biases that can affect your behaviors and decisions, from the mundane to the life-changing. While it may be easier to recognize the phenomenon in others, it is important to remember that it is something that impacts everyone. By understanding the underlying causes that contribute to this psychological bias, you might be better able to spot these tendencies in yourself and find ways to overcome them.

8 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Kendra Cherry
Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology.