Unskilled and unaware of it – The Dunning-Kruger Effect

Gorilla unsure of his ability – Photo Credit: Steven Straiton

The fool doth think he is wise, but the wise man knows himself to be a fool.

-Shakespeare, As you like it, Act 5 Scene 1

In 1995 a short, fat, very recognisable man called Macarthur Wheeler robbed 2 banks at gunpoint in Philadelphia. He didn’t bother to cover his face. Obviously, the police had no trouble identifying and arresting him. He was quite puzzled. After all, he claimed, he had covered his face in lemon juice.

You see, Wheeler believed that if he covered his face in lemon juice, it would have become invisible to the closed-circuit cameras. He even tested this, he covered his face in lemon juice, then, while squinting his eyes and tearing up in pain, he had taken a selfie with a polaroid camera. In the developed picture he was nowhere to be seen. So obviously, it had worked. Except that it hadn’t. Either the polaroid film had expired or been damaged or he simply did not manage to point the camera at himself and instead took a snap of the empty room behind him.

Real knowledge is to know the extent of one’s ignorance.


Wheeler had no idea just how bad he was at being a criminal. He was unaware of his incompetence. He wasn’t just stupid, he was so stupid that he couldn’t understand that he was so stupid.

David Dunning, a professor of social psychology at Cornell University, read this article and was intrigued. This man was too incompetent to know that he was incompetent. But were all inept people unaware that they were inept?

So, together with Justing Kruger, one of his graduate students, devised several studies to test this hypothesis.

University students were given tests to measure their ability in grammar, logical reasoning and their understanding of humour. In all of the studies students that were performing badly consistently overestimated their performance, judging themselves to be above average. When shown tests by other students they were unable to understand the competence of others.

If you’re incompetent, you can’t know you’re incompetent. […] If you knew it, you’d say, “Wait a minute.  The decision I just made does not make much sense.  I had better go and get some independent advice.”   But when you’re incompetent, the skills you need to produce a right answer are exactly the skills you need to recognize what a right answer is.

-David Dunning, as quoted here

People in the bottom quarter of the participants, whose average scores put them in the 12th percentile, overestimated their ability and thought, on average, that they belonged in the 62nd.

Another result of the study was that highly competent people were also unable to correctly assess their ability, though, differently from unskilled participants, they tended to under estimate their ability. Dunning and Kruger propose that they are victims of the false consensus effect. Because it’s easy for them, they assume that it must be easy for everyone else too.

The inability of incompetent people to judge their own performance has been named the Dunning-Kruger effect, after the authors of the study. A 2008 study by Ehrlinger et al. further reinforced Dunning and Kruger’s conclusions: “People are typically overly optimistic when evaluating the quality of their performance on social and intellectual tasks. In particular, poor performers grossly overestimate their performances because their incompetence deprives them of the skills needed to recognise their deficits. Five studies demonstrated that poor performers lack insight into their shortcomings even in real world settings and when given incentives to be accurate.”

Unknown unknowns

There are known unknowns; that is to say, there are things that we now know we don’t know.
But there are also unknown unknowns – there are things we do not know we don’t know.

-United States Secretary of Defense, Donald Rumsfeld (wiki link)

Donald Rumsfeld got a lot of criticism for this statement, but while it might have been a way to evade the journalist’s probing, the underlying reasoning does actually make sense. Hear me out.

Take for example, the temperature of the surface of the sun. You might not know exactly what it is, but you know that you don’t know. However, there could be questions or problems or issues of which you have no perception of. You don’t know that those issues exist, so you don’t know that you don’t know.

The only true wisdom is to know that you know nothing.


You can prepare for a known unknown. You can do risk assessment, take out insurance, plan for the eventuality. But things you don’t know you don’t know can blindside you because you were not expecting them at all. You were unaware of their existence.

Unknown unknowns can lead to non-optimal solutions for problems. You might find an excellent solution based on what you know, but what if there are factors of which you don’t know the existence of? You didn’t consider them, because you didn’t know they were there.

I don’t know if I’m any good at this

One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision.

-Bertrand Russell

Sometimes I do worry that I’m really bad at this. Writing this blog-thing. After all, if I’m actually terrible at it, it’s not like I would have any way of knowing (unless I got lots of people throwing digital rotten tomatoes at me in the form of angry, angry comments). But then, if I worry about my ability, doesn’t that make me part of the people who are aware of their failings? Now I’m just confused.


References and further reading

  • http://shiggyenterprises.wordpress.com Dirk Porsche

    There can be positive comments from people who don’t have any perception of the problem domain either and encourage you in your stupidness.

    That’s the reason why the most untalented people show up on talent shows and have their whole family and friends standing united behind them. And they don’t understand it afterwards, that their “star” got a rude rejection.

    Self doubt is a good thing.

    And yes, in my opinion, I doubt that I’m any good at this blogging thing either, think you have a wonderful blog.

    Just to add to the confusion.

    • http://piecubed.wordpress.com piecubed

      And yes, self-doubt is important as long as you don’t have too much of it, which can become crippling. You have to fight through your own criticism.

      This quote is thrown around a lot on the internet, but it definitely applies:
      “Nobody tells this to people who are beginners, I wish someone told me. All of us who do creative work, we get into it because we have good taste. But there is this gap. For the first couple years you make stuff, it’s just not that good. It’s trying to be good, it has potential, but it’s not.
      But your taste, the thing that got you into the game, is still killer. And your taste is why your work disappoints you. A lot of people never get past this phase, they quit. Most people I know who do interesting, creative work went through years of this. We know our work doesn’t have this special thing that we want it to have. We all go through this. And if you are just starting out or you are still in this phase, you gotta know its normal and the most important thing you can do is do a lot of work.
      Put yourself on a deadline so that every week you will finish one story. It is only by going through a volume of work that you will close that gap, and your work will be as good as your ambitions. And I took longer to figure out how to do this than anyone I’ve ever met. It’s gonna take awhile. It’s normal to take awhile. You’ve just gotta fight your way through.”
      -Ira Glass, host of This American Life

      • http://shiggyenterprises.wordpress.com Dirk Porsche

        True words.

        I have no intentions on quitting, yet. It’s to much fun, for now.

        But we will see how long this will be the case.

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  • http://omg-occasionalmuffledgrunts.blogspot.co.uk/ Jez Bayes

    Which is worse: President Dunning Kruger, or the Dunning Kruger electorate?