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Objectivity's Blind-Spot: The Dunning-Kruger Effect

Why are people’s thoughts obscured by their absolute belief in the correctness of their opinions? Why do individuals who lack certain abilities believe they are exceptionally qualified? It all comes down to the Dunning-Kruger effect.

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Objectivity's Blind-Spot: The Dunning-Kruger Effect

The Dunning-Kruger Effect

“The fundamental cause of the trouble in the modern world today is that the stupid are cocksure while the intelligent are full of doubt.”

-- Bertrand Russell, mathematician, Nobel laureate

Though Bertrand Russell uttered this thought over half a century ago, the validity of his words has not changed since then. Evidence of this has been provided by the scientific research of Cornell University’s David Dunning and Justin Kruger. Through their research, the two scientists uncovered a phenomenon known today as the Dunning-Kruger effect.

The Thief That Was Invisible

Dunning and Kruger’s research was inspired the curious incident of Pittsburgh’s “lemon thief,” McArthur Wheeler, who, in broad daylight and without any disguise whatsoever, robbed not one but two banks. Thanks to surveillance footage, the police were able to identify and apprehend him quite quickly after the robberies. Curiously, Mr. Wheeler was very surprised about being caught, stating that he had, after all, worn the juice!

Wheeler had been operating on the basis of the very misleading notion that if he covered his face (and even his eyes) with lemon juice, it would make him invisible to cameras. This is a nonsensical hypothesis to us, but it represented an irrefutable truth to him. Why?

Our perceptions of how the world works are called mental models. Wheeler’s absurd mental model regarding the invisibility properties of lemon juice are just one extreme example of a frequent phenomenon where people have more or less “odd” perceptions of the world. In such cases, people steadfastly believe in their mental models and make their decisions based on them without giving them any critical thought. It is precisely this phenomenon that Dunning and Kruger decided to investigate.

Hypothesis: A Person’s Ignorance Prevents Them from Realizing Their Own Ignorance

The scientists were piqued by the very apparent distinction between the true abilities and knowledge of a person and the way that person sees their own abilities. They formulated the hypothesis that a person who lacks competence suffers from two kinds of setbacks:

  • They make bad decisions due to their ignorance. For example, they try to rob a bank after smearing lemon juice all over their face.
  • They are unable to realize that they are making bad decisions based on their own lack of competence. Wheeler remained unconvinced of his incompetence even after viewing the surveillance videos of himself. He believed them to be fake.

The Core of the Research: An Ignorant Person is Convinced They are Smart

To prove this hypothesis, Dunning and Kruger conducted the following experiment on a group of university students:

  • At first the students were asked to complete a test assessing their capabilities in certain areas (logic, grammar, and humor.)
  • After the test they were asked to assess their own levels of competence in the tested areas. In other words, they were asked to guess how capable they were in what they. Had been tested on.

Dunning-Kruger research results chart

You can see what the final results were in the chart. The research came up with two very obvious findings:

  • People who are the least competent people overestimate themselves the most. The quarter of the students with the poorest performance – having achieved an average percentile of 12 – had expected to perform at an average percentile of 62.
  • On the contrary, more capable individuals have a tendency to underestimate their abilities.

The Sharing of the Research Results Led to No Change

“Stupid is as stupid does.”

-- Forrest Gump

In the second portion of the experiment, the students had the opportunity to examine the test results of the other participants and once again make self-assessments of their abilities.

This part of the experiment resulted in two findings:

  • After comparing their results with those of everybody else, the more competent individuals realized that their abilities were better than they thought they were. This initial underestimation is due to the fact that if an individual believes that something is easy for them, then it must also be easy for others.
  • The individual who were less competent did not change their self-assessments even after seeing the actual test results. They were unable to identify that the abilities of the other test-takers were better than their own.

Education as the Path towards Objectivity

Thanks to further testing, the experiment-runners were able to conclude that more accurate assessments both of one’s self and of others can only be reached through training. In other words, if a person’s abilities improve, then they are able to identify their original lack of ability.

Conclusion: People Who Don’t Know are Unaware that They Don’t Know

Unskilled people make poor decisions and reach erroneous conclusions, but their incompetence denies them the metacognitive ability to appreciate their mistakes.

-- Dunning-Kruger effect, Cornell University

The research ultimately revelaed the following:

  • Individuals lacking in competence have the tendency to overestimate their abilities
  • Incompetent individuals are unable to identify the abilities of others
  • After being confronted with reality, these individuals will not change their positions
  • The only way to overcome the Dunning-Kruger effect is to improve one’s skills through education and training

The Properties of the Human Brain

There is condition called anosognosia which may indicate that the Dunning-Kruger effect is in fact a defensive mechanism of the human brain. This condition sometimes manifests in medical patients who have lost an arm or a leg. The patient still thinks they have the limb in question, and it’s impossible to explain to them that they don’t. There have even been cases where it was impossible to explain to a person affected by blindness that they are in fact blind. This is because the human brain is capable of subconsciously shutting out any information that may indicate lack of ability. It’s therefore possible that it blocks out information regarding the incorrectness of one’s mental models in the very same way.

How to Combat the Dunning-Kruger Effect

Have you ever met an extremely awkward person who thought they were nothing less than a star comedian? Have you have ever been shocked by the blatant absurdity of arguments in the comments section under various articles on the Internet? Has anyone ever tried to convince you that humans can survive for six years without food and that it’s healthy to drink your urine in the morning? Do you know anyone who is absolutely unshakable when it comes to believing in mental models that make absolutely no sense to you?

Each one of us regularly interacts with individuals suffering from the Dunning-Kruger effect. Even if you think that a certain “expert” may be wrong when it comes to their claims, it’s not possible to convince them of this using logical arguments. Research has shown that this effect is quite widespread. In certain areas, we can all be victims of it. How then can we avoid it?

Do Not Make Steadfast Opinions on Matters You Know Little About

Disinformation, a lack of information, or information skewed by the media are dangerous. If you are going to be choosing positions on matters about which you have little or no trustworthy information, you are at risk of becoming susceptible to the Dunning-Kruger effect. Therefore, you should look towards gaining objective information by getting it from quality sources such as academic research.

Don’t Have Dogmas

A classicist would say: “The only dogma that I have is that I don’t have dogmas.”

The concept behind this quote is an effective tool towards preventing the onset of the Dunning-Kruger effect. Even if you believe in something very deeply, try acknowledging that it just might not be true. Always acknowledge the possibility that you may be under the influence of the Dunning-Kruger effect. If Adolf Hitler and Anders Breivik had acknowledged this, for example, then their actions may not have reached the scale that they did.

Educate Yourselves and Seek Feedback

Start to actively question your intuition and subjective opinions. Seek out the truth and ask for objective feedback. You should value this feedback more than your own opinions. When it comes to combatting the Dunning-Kruger effect, education and lifelong learning make up the foundation.

A Philosophical Conclusion to Finish Off

Truth and objectivity are some of the most important values when it comes to the development and functioning of society. Because it can cloud our minds against objectivity, the Dunning-Kruger effect is an enemy. The main risk this phenomenon poses is that it can be contagious. So, don’t let yourself get caught up in it!

"Ignorance more frequently begets confidence than does knowledge."

-- Charles Darwin

The End of Procrastination

This is an excerpt from the book The End of Procrastination with description of Dunning-Kruger effect.

The End of Procrastination - Chapter Objectivity - Dunning-Kruger

Learn more about the book


  • Kuger, J. and Dunning, D.: Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments: Psychology, 2009, 1, 30-46.
  • Kuger, J. and Dunning, D.: Unskilled and Unaware of It: How Difficulties of Recognizing One’s Own Incompetence Lead to Inflated Self-assessments: Journal of Personality and Social Psychology, 1999, vol. 77, no. 6, pp. 1121-1134.
  • Dunning, D.: Self-Insight: Roadblocks and Detours on the Path to Knowing Thyself (Essays in Social Psychology: Psychology Press: 2005, s. 14–15. Ehrlinger, J.; Johnson, K.; Banner, M.; Dunning, D.; Kruger, J.: Why the unskilled are unaware: Further explorations of (absent) self-insight among the incompetent: Organizational Behavior and Human Decision Processes: 2008.
  • Interview with Justin Dunning
  • Wikipedia article

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