Dunning-Kruger Effect

“Clowns to the left of me, jokers on the right.”  Ever had that feeling?

There’s a name for the cause of that feeling:  The Dunning-Kruger Effect.

The Dunning–Kruger effect is a cognitive bias in which unskilled individuals suffer from illusory superiority, mistakenly rating their ability much higher than average. This bias is attributed to a metacognitive inability of the unskilled to recognize their mistakes

Where did we first start calling it the Dunning Kruger Effect?  After this paper in 1999:

Journal of Personality and Social Psychology
Journal of Personality and Social Psychology (Photo credit: Wikipedia)

Unskilled and unaware of it: How difficulties in recognizing one’s own incompetence lead to inflated self-assessments.

Kruger, Justin; Dunning, David

Journal of Personality and Social Psychology, Vol 77(6), Dec 1999, 1121-1134.

People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it. Across 4 studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability. Although their test scores put them in the 12th percentile, they estimated themselves to be in the 62nd. Several analyses linked this miscalibration to deficits in metacognitive skill, or the capacity to distinguish accuracy from error. Paradoxically, improving the skills of the participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

Others had noted the effect earlier, but described a bit differently, or failed to set up experiments to confirm it as Dunning and Kruger did.  If you watch, you’ll see it all around you.

Bertrand Russell observed eight decades ago:

The trouble with the world is that the stupid are cocksure
and the intelligent are full of doubt.

– Bertrand Russell, The Triumph of Stupidity in Mortals and Others: Bertrand Russell’s American Essays, 1931-1935 (Routledge, 1998), p. 28

Calvin and Hobbes give a demonstration; found at Psychology Today blogs

We see it here, at the bathtub, with the occasional e-mail objecting that Millard Fillmore did, in fact, put the first bathtub in the White House.  The e-mail will suggest we should read some history books to see.  Or, we’ll see a lot of it in the textbook debates at the Texas State Board of Education, with people arguing that they know Darwin recanted, that all fossils are made up, and that DNA is a fiction, because they heard it at Sunday school, and Sunday school teachers would not lie.

Sometimes it’s difficult to separate Dunning-Kruger from just plain old gullibility; and how can we really distinguish it from the (misnamed) Barnum Effect (really, the Forer Effect)?

Dr. David Dunning, Cornell University psychologist
Dr. David Dunning, Cornell University psychologist [at the University of Michigan, Ann Arbor in 2020]

Sniffing out stupid and humorous, and sometimes malicious, distortions of history, we run into people under the spell of the effect way too often.

I’ve written about it rather randomly here before; this page is put here to pull the resources together in one convenient location.

To understand the effect, and the history, you should see these posts:

The “triumph of stupidity.”  Avoid it at all costs.

What examples do you have of the Dunning-Kruger effect?  Comments are open.

Dr. Justin Kruger, Cornell University psychologist
Dr. Justin Kruger, New York University – Stern School of Business psychologist

More, and other resources:

45 Responses to Dunning-Kruger Effect

  1. Ed Darrell says:

    Hawking, describing Dunning Kruger pragmatically.


  2. Ed Darrell says:

    John Cleese knows.


  3. Dieter Kief says:

    The Dunning Kruger effect might not be real. And it is misunderstood by most because it – according to Dr. David Dunning – is only properly unerstod as being about us, – not them! – It was .n.o.t. meant to show how biased the uneducated are.



  4. Ed Darrell says:

    Dunning Kruger effect and global warming.


  5. Ed Darrell says:

    This is good: Dunning’s TEDS talk.


  6. Ed Darrell says:

    Is it a form of Dunning Kruger Effect? Maybe we need to renew this post and expand it to cover conspiracy idea victims.


  7. Ed Darrell says:

    In all disciplines?


  8. Ed Darrell says:

    A story of Dinning Kruger effect in our time.

    Thread here:


  9. Ed Darrell says:

    Dunning Kruger effect still plagues us.



  10. Ed Darrell says:

    The counter case?


  11. Ed Darrell says:

    Good one! Thanks for the pointer to Yeats. Didn’t know.


  12. Joseph Proskauer says:

    “The best lack all conviction, while the worst
    Are full of passionate intensity. “

    WB Yeats, “The Second Coming”
    Written 1919, published 1920


  13. Ed Darrell says:

    Dunning Kruger effect found in climate change discussions.


  14. Ed Darrell says:

    More examples.


  15. Ed Darrell says:

    And, on to antivaccine stuff:


  16. Ed Darrell says:

    Claims of such studies are a demonstration of the Dunning Kruger effect.


  17. lagergeld says:

    Striving for accuracy in science? ORLY?

    Why not discuss that IQ studies consistently show unequal IQ averages between human racial and ethnic groups?


  18. Ed Darrell says:

    At no point I’ve found do the researchers say this is the final answer to anything.

    Do you disagree? Why? What’s your evidence?


  19. Len says:

    Another FINAL answer to authority! Congratulations as the Psych approach is made manifest by…guess who, the Psych folks themselves.
    “Believe what we, or I, tell you because we are experts and have crossed your bridge of stupidity and ignorance”.
    Ask an aeronautical engineer how bumble bees fly. Hell, they don’t even agree on how airplanes lift.


  20. Ed Darrell says:

    A modern demonstration of Dunning Kruger Effect and the Rogers-Hubbard Corollary, that it’s not what we DON’T know that gets us into trouble, but what we know, that is not so:


  21. Ed Darrell says:

    From Dr. Dunning hisownself, probably good advice:


  22. Ed Darrell says:

    We need to track this one down. Did Twain really say it?

    No. Turns out Twain didn’t say it. http://ianchadwick.com/blog/and-again-more-mis-attibuted-quotes-online/

    Who did?


  23. Ed Darrell says:

    You can get even better background from this podcast, I’ll wager:


  24. Ed Darrell says:

    Oops! Note chart, claimed to be from some knowledgeable person, has some glaring errors, and fails to cite itself to Saturday Morning Breakfast Cereal cartoon (linked in the article above):


  25. Ed Darrell says:

    This climate “skeptic” blog at least provides a warning, rather like a skunk raising its tail, when it posts Daniel Boorstin’s words in the upper right corner.



  26. Ed Darrell says:

    Great point. In my years staffing the Senate, I was astounded at how often senators were happy to block legislation based on some point of misinformation or disinformation they had seized on, after their colleagues had spent years gathering the information, writing the law, holding hearings, refining the legislation, and battling lobbyists to get the bill done.

    The general public is no better than senators in that regard. Sadly.


  27. Funny, I just blogged about the D-K effect and American race relations, with individuals differing perceptions of the national and local scene, earlier this week: http://socraticgadfly.blogspot.com/2015/07/the-dunning-kruger-effect-and-race.html


  28. Ed Darrell says:

    Darwin’s observations on the Dunning Kruger Effect:


  29. Ed Darrell says:

    Rats can be smarter than humnans?

    That’s not an excuse for humans to act stupider, or meaner, than rats.


  30. Ed Darrell says:

    John Cleese on something akin to the Dunning Kruger Effect:


  31. Ed Darrell says:

    Quotes Dunning himself:


  32. Ed Darrell says:

    [Not sure what happened to video below; looking for another copy, or where the site moved.]

    (Thanks to @uknowISS)


  33. Wesley Dunning says:

    I am a dunning I wonder if the good doctor has the same dunning effect that all the Dunnings I know have.? They think they know it all clowns to the left of me jokers to the right! But the doc. Left out the most important part. Here I am stuck in the middle with you! The true Dunning effect.


  34. Wesley Dunning says:

    I am a dunning I wonder if the good doctor has the same dunning effect that all the Dunnings I know have.? They think they know it all


  35. Ed Darrell says:

    Cartoon fan Donald Prothero posted at his Facebook site:


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