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The Dunning-Kruger Effect

By Mike Davis, Th.M., BCC, CWMF

These days we prize our certainty above all, science be damned.

A well-known study, Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments, explored the disturbing likelihood that the more we tend to think ourselves experts on a subject, the less likely we are to be correct. The opposite is also true: the less we think we know about any subject, the more expert we probably are. This phenomenon is called the Dunning-Kruger Effect, named after David Dunning and Justin Kruger. See more []

Here’s the background. When captured, a bank robber, McArthur Wheeler, was dismayed that police had been able to identify him, even if they did use the bank camera. Police shouldn’t have been able to identify him because he “Wore the juice”. The juice should have hidden his identity.

When police pressed him further about the juice he explained that he’d covered himself with lemon juice. As you may know, lemon juice is used in invisible ink. So, if he was covered in the juice - invisible ink - he should have been invisible. He assumed a level of expertise about lemon juice he didn’t possess.

We shouldn’t be too quick to laugh at poor Mr. Wheeler. Dunning and Kruger’s research suggested that humans routinely do this. More importantly, if questioned about almost any subject of which we know avery little, you and I would do exactly what Mr. Wheeler did.

As many Living Wills and Medical Powers of Attorney as I’ve done, I realize I’m still learning. Still, it’s hard when a patient or family member - feeling a sense of Dunning-Kruger expertise - won’t listen to feedback from someone who’s done thousands of these and seen the results of advance directives done poorly.

Or, patients ignore physicians recommendations with frequently tragic results. Often, they are readmitted in worse condition than when they insisted on leaving. If they survive at all. But, of course, they know best: they have to go home and take care of a business matter, or they have to _________ ___.

With Mr. Wheeler’s voice of surprise, they say, But, I was wearing the juice.

  1. Wikipedia, Dunning–Kruger effect
  2. Psychology Today, Dunning-Kruger Effect
  3. Poundstone, William: Medium, June 14, 2016
  4. Link [to the actual article](http://www.sakkyndig.com/psykologi/artvit/dunning1999.pdf
  5. Video from TED-Ed: Why incompetent people think they’re amazing

Edit: Since posting this, the Dunning-Kruger Effect has been called into question (with good evidentiary basis). The summary version of the new updates says the following. The original conclusions were thus:

Certainty in the new Dunning-Kruger:

  1. The person who knew nothing about a subject in general feels they know about a subject (but is clearly not an expert).

  2. The expert in that subject generally feels s/he doesn’t know enough to be considered an expert.

  3. The expert in that subject will regard himself as expert in other subjects in which s/he is not an expert, just like anybody else.

  4. The point is that experts who are humble in their area of expertise will infer or claim expertise in other areas where they really aren’t experts. We often see this in news reports after some event where someone is interviewed who only has tangential knowledge of the subject.

Other articles here: Canady, Brittany E., and Mikayla Larzo. “Overconfidence in Managing Health Concerns: The Dunning–Kruger Effect and Health Literacy.” Journal of Clinical Psychology in Medical Settings 30, no. 2 (2023): 460–68. https://doi.org/10.1007/s10880-022-09895-4.

Coutinho, Mariana V. C., Justin Thomas, Alia S. M. Alsuwaidi, and Justin J. Couchman. “Dunning-Kruger Effect: Intuitive Errors Predict Overconfidence on the Cognitive Reflection Test.” Frontiers in Psychology 12 (April 8, 2021): 603225. https://doi.org/10.3389/fpsyg.2021.603225.

Dunkel, Curtis S., Joseph Nedelec, and Dimitri van der Linden. “Reevaluating the Dunning-Kruger Effect: A Response to and Replication of Gignac and Zajenkowski (2020).” Intelligence 96 (January 1, 2023): 101717. https://doi.org/10.1016/j.intell.2022.101717.

Jansen, Rachel A., Anna N. Rafferty, and Thomas L. Griffiths. “A Rational Model of the Dunning–Kruger Effect Supports Insensitivity to Evidence in Low Performers | Nature Human Behaviour.” Nature Human Behaviour 5, no. 6 (June 2021): 756–63. https://doi.org/10.1038/s41562-021-01057-0.

Magnus, Jan R., and Anatoly A. Peresetsky. “A Statistical Explanation of the Dunning–Kruger Effect.” Frontiers in Psychology 13 (March 25, 2022): 840180. https://doi.org/10.3389/fpsyg.2022.840180.

Mazor, Matan, and Stephen M. Fleming. “The Dunning-Kruger Effect Revisited | Nature Human Behaviour.” Nature Human Behaviour 5, no. 6 (June 2021): 677–78. https://doi.org/10.1038/s41562-021-01101-z.

“(PDF) Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments.” Accessed September 23, 2023. https://www.researchgate.net/publication/12688660_Unskilled_and_Unaware_of_It_How_Difficulties_in_Recognizing_One’s_Own_Incompetence_Lead_to_Inflated_Self-Assessments.