The Dunning-Kruger effect

Chain-link fence

The idea of the Dunning-Kruger effect is that people who are incompetent at something often lack the skills necessary to appreciate their own incompetence, largely because the skills required for self-examination are similar to those required for competence in the task being evaluated. As discussed in this video, this effect seems to hold in areas as diverse as appreciating what people in general will find funny, grammar, and logical reasoning. A similar phenomenon shows up in surveys where the great majority of drivers claim that they are in the top 50% of drivers, ranked by skill. Obviously, many of them are overestimating their abilities, or underestimating those of their peers.

It would be interesting to see if it holds in relation to climatic science. As an experiment, people could be given a test that evaluates whether they can respond intelligently to scientific information about climate change. This could include things like whether they understand the difference between the stock of greenhouse gasses in the atmosphere and the flow of those gasses into it. If the pattern that emerged from scoring those tests and having people self-assess their competence held to the Dunning-Kruger pattern, that might help explain just how challenging it has been for the general public to acquire a working knowledge of climatic science, and ability to identify and reject bogus arguments about it.

An elaboration of the Dunning-Kruger experiments provides interesting additional insight. Highly competent and highly incompetent people are brought back, after having taken a test and rated their performance relative to others. They are then given a sample of other people’s responses to grade. Apparently, competent people realize that they previously overestimated the competence of their peers, and adjust their self-assessment to better match their position in the real distribution. This effect is apparently not seen in highly incompetent people, who fail to recognize their own mediocrity, even when confronted with evidence of it.

Author: Milan

In the spring of 2005, I graduated from the University of British Columbia with a degree in International Relations and a general focus in the area of environmental politics. In the fall of 2005, I began reading for an M.Phil in IR at Wadham College, Oxford. Outside school, I am very interested in photography, writing, and the outdoors. I am writing this blog to keep in touch with friends and family around the world, provide a more personal view of graduate student life in Oxford, and pass on some lessons I've learned here.

7 thoughts on “The Dunning-Kruger effect”

  1. There’s an actual name for it? Damn!

    I’ve said for years that some people are too dumb to know they’re dumb. I still say it often. If only I’d had the foresight to write it up with a quasi-scientific label…

  2. I failed your climate change test (or you failed the grammar test, but I actually don’t know which). I didn’t understand:

    “This could include things like whether they understand the difference between the stock of greenhouse gasses into the atmosphere and the flow of those gasses into it.”

  3. Coyote,

    A label wouldn’t have been enough. You would also have required some charts.


    I fixed the grammar.

  4. While it is easy to make fun of this, the insight is a fairly important one. If the skills required to be competent at something are the same as those required to judge your competence, it is understandable that many people overestimate their skill at a lot of things.

  5. “Although you might expect people who seek out obscure products to derive more pleasure from their discoveries than those who simply trudge off to see the occasional blockbuster, the opposite is true. Tom Tan and Serguei Netessine of Wharton Business School have analysed reviews on Netflix, a popular American outfit that dispatches DVDs by post and asks subscribers to rate the films they have rented. They find that blockbusters get better ratings from the people who have watched them than more obscure ones do. Even the critically loathed “Transformers: Revenge of the Fallen” is awarded four stars out of five. Ms Elberse of Harvard Business School has found the same of ratings on Quickflix, the Australian equivalent of Netflix.

    Perhaps the best explanation of why this might be so was offered in 1963. In “Formal Theories of Mass Behaviour”, William McPhee noted that a disproportionate share of the audience for a hit was made up of people who consumed few products of that type. (Many other studies have since reached the same conclusion.) A lot of the people who read a bestselling novel, for example, do not read much other fiction. By contrast, the audience for an obscure novel is largely composed of people who read a lot. That means the least popular books are judged by people who have the highest standards, while the most popular are judged by people who literally do not know any better. An American who read just one book this year was disproportionately likely to have read “The Lost Symbol”, by Dan Brown. He almost certainly liked it.”

  6. The Six Americas of Climate Change
    Posted by Clark Williams-Derry

    My favorite is this: folks who are convinced that global warming is a hoax — the “Dismissives” — admit they haven’t thought all that much about the issue (see Figure 6 on page 14 of the pdf) yet rank themselves as extremely knowledgeable and well informed (see Figure 7).

    That should tell us something: for many climate skeptics, facts don’t matter much. They’ve only given the subject a bit of thought, but are still convinced that they know the answers. I don’t mean to be snarky, but to me this suggests that some “Dismissives” may suffer from some version of the Dunning-Kruger effect — the idea that people are very poor judges of their own incompetence. That probably makes many “Dismissives” unreachable: when facts confront their biases, the facts bounce off and the biases stand firm. (I’m sure that’s true of us all, to some degree or another.)

  7. “It is also true that the less competent a person is in a given domain, the more he will tend to overestimate his abilities. This often produces an ugly marriage of confidence and ignorance that is very difficult to correct for. Conversely, those who are more knowledgeable about a subject tend to be acutely aware of the greater expertise of others. This creates a rather unlovely asymmetry in public discourse – one that is generally on display whenever scientists debate religious apologists. For instance, when a scientist speaks with appropriate circumspection about controversies in his field, or about the limits of his own understanding, his opponent will often make wildly unjustified assertions about just which religious doctrines can be inserted into the space provided. Thus, one often finds people with no scientific training speaking with apparent certainty about the theological implications of quantum mechanics, cosmology, or molecular biology.”

    Harris, Sam. The Moral Landscape. p.123-4 (hardcover)

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