The ‘Dunning Kruger Effect‘ (DuKE) has been discussed here before. The DuKE means that, the less you know, the less able you are to recognize how little you know, and the less likely you are to recognize your limitations. Consequently, your confidence in yourself is inflated and you believe you are more competent than your opponent. Expressed differently:

  • Incompetence prevents the recognition of incompetence.
  • Too stupid to doubt.

A recent paper brilliantly shows the DuKE in action; here is its abstract

There is widespread agreement among scientists that genetically modified foods are safe to consume and have the potential to provide substantial benefits to humankind. However, many people still harbour concerns about them or oppose their use. In a nationally representative sample of US adults, we find that as extremity of opposition to and concern about genetically modified foods increases, objective knowledge about science and genetics decreases, but perceived understanding of genetically modified foods increases. Extreme opponents know the least, but think they know the most. Moreover, the relationship between self-assessed and objective knowledge shifts from positive to negative at high levels of opposition. Similar results were obtained in a parallel study with representative samples from the United States, France and Germany, and in a study testing attitudes about a medical application of genetic engineering technology (gene therapy). This pattern did not emerge, however, for attitudes and beliefs about climate change.

As I have stated before, I suspect the DuKE can explain much of what is going on in the realm of SCAM (so-called alternative medicine). So much so that I am tempted to re-write part of the above abstract as follows:

As extremity of belief in SCAM increases, objective knowledge about science and medicine decreases. In parallel, perceived understanding of science and medicine increases. Extreme believers in SCAM know the least, but think they know the most. Moreover, the relationship between self-assessed and objective knowledge shifts from positive to negative at high levels of SCAM-belief.

Yes, yes, I know. You are absolutely correct: this is little more than speculation! And I also realise, of course, that not everyone can have a full understanding of SCAM, medicine and science; however, if someone has a strong interest in (plus a strong opinion of) these matters, it would be advisable to read up about at least the most basic facts.

In case you disapprove, please do have a look at some of the recent comments on this blog or assess what some of the most famous proponents of SCAM tell the public, and I am confident that you will begin to suspect that my speculation might be not that far off the mark.

9 Responses to The ‘Dunning Kruger Effect’ in action

  • My thoughts exactly, Edzard. I suspect if this exercise was re-run with staunch anti-vaxxers it would return similar results.

  • A colleague and I were just talking about this at work while giggling about the scientific implausibility of homeopathy. A few people at work especially ‘architects’ (as in software / infrastructure / network ) suffer from this.

  • I have just been rereading Bob Altemeyer’s book The Authoritarians and in one chapter he is discussion the relationship of religious fundamentalism and authoritarianism.

    He reports that in his samples, mainly university students, the fundamentalists who embrace the bible usually have not read it or have only read very small, selected bits.

    I had not considered it before, but we do seem to have a case of DuKE there.

    • In my experience, fundamentalists are not encouraged to read the bible. They are more often required to accept what their leaders tell them about the bible

  • Thanx for posting this article…and what is so remarkable about this article is that your website proves the veracity of DuKE, especially in the raving ignorance AND arrogance that the people here have on the subject of homeopathy. Despite the embarrassing ignorance on the subject, the amount of arrogance that they have is remarkable.

    Now, let the ad homs begins…

    • forgive me, but I honestly think that you demonstrated amply how insufficient you knowledge in all these areas is and how much your views are obstracted by blinkers.

    • Similarly Dana none of us have any knowledge of the anatomy, physiology, biochemistry, language, sociology or history of fairies and as such we are in absolutely no position to pass any comment on wether they exist. I myself know very little about aeronautics. Typically arrogant and DuKE-esque of me to suggest that magic carpets can’t fly.

  • Boys! Boys!
    Dunning and Kruger help us better understand how many apparently rational people continue to pursue implausible beliefs.

    When I wrote Real Secrets of Alternative Medicine , Cognitive Bias (of which DK is a prime example) was ‘secret’ 16 out of 33 I identified as causing folks to take to camistry/SCAM – “illusory superiority” stemming from an error about the self (in people of low ability), or about others (in people of high ability).

    Not all camists (who practice camistry) and camees (who are SCAMed) are open minded and prepared to change their opinion in the light of evidence. Proverbs had: “The way of a fool seems right to him but a wise man listens to advice” and; “In everything the prudent acts with knowledge but a fool flaunts his folly.” Touchstone in Shakespeare’s As You Like It recalled an old saying: “The fool doth think he is wise but the wise man knows himself to be a fool”; and Charles Darwin: “Ignorance more frequently begets confidence than does knowledge.”

    Originally, Dunning and Kruger tested the hypotheses of the cognitive bias of illusory superiority on undergraduate students of introductory courses in psychology by examining the students’ self-assessments of their intellectual skills in logical reasoning (inductive, deductive, abductive), English grammar, and personal sense of humor. (Wikipedia).

    A bit more insight from some contributors to this blog (and all camists) is surely called for.

  • I liked Steven Novella’s writing on this GMO-opponent-study and Dunning Kruger in general. Two points I’d like to bring to attention:

    -The effect in this study is not just Dunning Kruger.

    “[…]Dunning-Kruger effect (DK) – the less someone knows about a topic the greater they overestimate their knowledge. Actually the pattern the current authors found is even more extreme that DK. In DK self-estimation still goes down with objective knowledge, but the degree to which people overestimate their knowledge increases. The current study is super DK – at the extreme end of opposition to GMOs, opponents actually knew the least about genetics but thought they knew the most.”

    (Super DK is a term made up by SN)

    In another post on DK in general:
    – Dunning Kruger is not something that happens to stupid people. We should all be cautious about it.

    “Further I need to emphasize that the data does not apply to “people” who are generally in the low percentiles of competence, but to everyone with respect to where they are with each individual area of knowledge. So the same person may be in the 80th percentile in one knowledge area, and the 20th percentile in another, and the graph above applies to them in both cases.


    I know this all may seem like nitpicking, but it is important to how the DK effect is interpreted. The vast majority of people who bring it up seem to think that it applies only to dumb people and that it says dumb people think they are smarter than smart people. Neither of these things are true. Further – if you think it only applies to other people (which itself, ironically, is part of the DK effect) then you miss the core lesson and opportunity for self-improvement and critical thinking.”

    Source 1:
    Source 2:

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