Confident dumb people

Have you ever noticed how incompetent people are often incredibly confident? Meanwhile, highly-skilled folks underestimate their ability to perform. That's called the Dunning-Kruger Effect named for Justin Kruger and David Dunning of Cornell University who published their study of the cognitive bias in a 1999 scientific paper. ABC Radio National's The Science Show recently explored the Dunning-Kruger Effect. According to the scientists, "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." ABC Radio National's The Science Show recently explored the Dunning-Kruger Effect:
Pittsburgh, Pennsylvania, 1995. A local man, McArthur Wheeler, walks into two banks in the middle of the day and robs them both at gunpoint. Making away with the cash, he is arrested later that evening. Back at the station police sit him down and show him footage from the banks' security cameras. Wheeler can't believe it, the cameras had somehow seen through his disguise. He was seen mumbling to himself, 'But I wore the juice.' His was no ordinary disguise; no balaclava, mask or elaborate makeup, just lemon juice, liberally applied to the face. He was certain that the squirt of citrus would render him invisible to security cameras.

Charles Darwin once said, 'Ignorance more frequently begets confidence than knowledge,' and Dunning and Kruger seem to have proven this point. In light of this, it suddenly becomes clear why public debate can be so excruciating. Debates on climate change, the age of the Earth or intelligent design are perfect real-life examples of the Dunning-Kruger effect. It beautifully explains the utter confidence of those who, with no expertise, remain stubborn in their views regardless of overwhelming evidence. It makes you want to shake them by the collar and scream about how stupid they are. But evidence shows that's not the best strategy.

"The Dunning-Kruger effect" (ABC Radio National)

"The research paper that first documented the Dunning-Kruger effect" (via @mgorbis)



  1. Wasn’t it Confucius who said something like. “Real knowledge is to recognize the extent of one’s ignorance”?

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

    Or was I supposed to say, “first?”

  3. “Have you ever noticed how incompetent people are often incredibly confident?”

    You sound very confident about this claim.

  4. It makes you want to shake them by the collar and scream about how stupid they are. But evidence shows that’s not the best strategy.

    Do they then go on to explain what the best strategy is? Because I’m going to go postal if I get in too many more arguments with climate change denialists or IDers.

    1. sloverlord, in case you missed it when you read the paper, teaching them the actual facts is way better than shaking them by the collar.

  5. …except that when you shake them by the collar and scream about how stupid they are, you’re falling into the exact same trap that they did. The moment you convince yourself that you are right and the other person can’t possibly be right, you are no better than a person who blinds himself to evidence. Though you may know of lots of evidence that backs up your side, and you’re sure there is no evidence to back up your opponent’s side, and you’re convinced that you’ve exhausted every available avenue of research, the moment you consider them a stubborn dunce in absolute terms, you’ve ruined your ability to be objective and open minded. So it’s not that that’s not the best strategy, it’s that it’s a non-strategy. You consider yourself to be an adult talking to a child, and thus become a child talking to a child.

    An adult leads by example, confident in his knowledge that he doesn’t have to prove everything to an impetuous child, because they will learn for themselves eventually, or prove that they never could have been convinced anyway by failing to adapt in the face of failure. What better way to prove Darwinian Evolution than to quietly allow those who are correct to prosper and those who are incorrect to flounder?

    1. Too bad that’s not how evolution works. Who do you think reproduces more? Also,intelligent people don’t necessarily prosper more than others,take a look around.

      Shaking someone isn’t the answer but staying quiet is worse than stupid. We don’t live in a vacuum, and we are all responsible for the world we live in at some level.

    2. Good point, except many of our current dilemas don’t really allow us to patiently sit back and watch them flounder. This is especially true when, in some cases, the ignorant simultaneously represent the majority

    3. The problem is that Darwinian Evolution is probably going to conclude that the Human Race is a failed experiment because it never evolved a method for dealing with idiots – idiots who are pulling down the rest of us through, to give only two examples, the destruction of the atmosphere and blind support for totalitarian dictators as long as they mumble something trite about “freedom” or “honour”.

      Most people would rather die than think and, the way things are going, it looks as if they’re about to get their option of choice.

  6. Yup, seen this many times… Ask any Trades Person when they are in the middle of doing something: “Hey, you sure you know what you are doing there?”
    The Master will almost always make a joke about not having a clue where a novice will always try to convince you of his expertise. I use this trick all the time with new guys on the jobsite to quickly access their skills.

    1. I use this trick all the time with new guys on the jobsite to quickly assess their skills.

      You seem to be very confident of your approach.

    2. My ex is a tradesman, in business 20 years. Few things make him nuttsier than the customer asking in the middle of a job, “Are you sure you know what you’re doing?” The best answer they can hope for is a very polite, “Yes sir, I am sure.” and a look that says, “If you have any doubts, why the H did you hire me??” He has very expressive eyebrows. He also dislikes being disturbed while working, as that can be dangerous. He won’t respond angrily unless he’s lost all patience with the customer and no longer cares about keeping the job.

  7. Learning instills (in the best cases) a feeling for the uncertainty of all knowledge. It’s easier to act confidently if you don’t know how likely it is that you are wrong.

    1. I completely agree with Schorsch. The more you know, the more you know you don’t know.

  8. “It makes you want to shake them by the collar and scream about how stupid they are. But evidence shows that’s not the best strategy.”

    Well, for the love of Shatner what is the best strategy (besides throwing millions of dollars at a professional PR firm to astroturf the opposition)? I know I can present evidence and studies and reasoned debate till I’m blue in the face, but that’s pretty boring stuff. I’ve learned by experience that there’s no way to drill through the truthiness of pop culture conspiracy theories because they’re romantic and exciting. Lots of people think science is boring stuff for eggheads and pocket protectors and playing D&D (of course, I live in Virginia so this is to be expected). Like Nero Wolfe, I cannot open their skulls to remove the offending brain cells.

  9. When arguing with someone with a set viewpoint, you’re running up against their internal Bayesian filter. ‘sent arguments like yours into the junk pile so often, everything similar gets tossed as junk as well.

    My trick is to use information, terminology, sources, etc that they’ve already put in the trusted pile. Tough to do, because you have to know the person pretty well. And you are not going to get them to change their mind. But you can, for just an instant, get them to see both sides. It’s a start.

    Take for instance the 6000 year earth. They take that as a sign of God’s power. I remind them of biblical quotes of God’s disregard for time. And I point out that creating the earth in 7 days and only having it up and running for 6000 years is weak compared creating the universe with a single act 14 billion years ago and planning ahead by that much time to produce us today. That’s omnipotence. Are they saying God is weak?

    Arguments like that

    1. You’re apparently referring to those few Christians who believe the Bible is to be read literally.

      Most educated Christians don’t believe that the Earth was created 6000 years ago. That’s nonsense.

      Educated Christians understand that, for example, 40 days and 40 nights is a Jewish storytelling device for saying “a long time,” not literally that time frame.

      In any event, the views of the uneducated few do not represent the views of most.

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

    –W. B. Yeats, “The Second Coming”

  11. ” The best lack all conviction, while the worst
    Are full of passionate intensity.” -Yeats

    I wonder how often these confidently ignorant folks extend the delusion of ability and correctness to their similarly ignorant peers. -Might help explain why all these lunkheads keep getting the cushy jobs and “nice” guys keep finishing last, arena after arena…

  12. I believe it was George Carlin who said, “Imagine the average American…half of them are dumber than that.”

  13. I shared this with others when I first heard about it, but when I really looked at the associated data chart, I had doubts.

    People in the lowest quadrant thought they were two quadrants higher (idiots!), people in the 2nd to lowest quadrant thought they were 1 quadrant higher (better…), people in the 2nd highest quadrant knew right where they were (clever!) and the people in the highest quadrant thought they were 1 quadrant lower (brilliant AND modest!).

    But isn’t a simpler reading of this data merely this: everyone puts themselves in the 2nd highest quadrant? People all think they’re above average and few people are willing to rank themselves at the top, even those that are at the top.

    1. That sounds like an alternative way of saying the same thing, rather than a different interpretation. If you place yourself in the second quadrant, then you’re misinterpreting your expertise whichever way.

  14. This article has thrown me into a personal Catch 22 crisis.

    Sometimes I feel confident and sometimes I feel clueless. As a confident person, I naturally assume that my feelings of cluelessness are due to the Dunning-Kruger Effect. That is, I think my feelings of inadequacy are caused by my fundamental adequacy. But I might be placing myself in the “smart enough to know I’m dumb” category when I’m actually in the “dumb enough to think I’m smart” category.

    Am I an idiot who is occasionally confronted with his own idiocy, or a genius who is occasionally prone to self doubt?

  15. Like Chris the Carpenter said, just as interesting as dumb people’s confidence is the honestly tentative and uncertain language used by really smart people.

    Who was it who originally wrote…

    You get your bachelor’s, and you think you know everything.
    You get your master’s, and you realize you know nothing.
    You get your PhD, and you realize NO ONE knows ANYthing.

    I have been through this progression at my job (even though I’m still only working on my master’s). I used to be an engineer, backing up my analyses by pointing to certain equations and material properties as though they were the word of God. Now I work at the research group responsible for coming up with those equations and properties. While some ways of doing things are better than others, it’s amazing how much I see handwaving and extrapolation and sketchy assumptions and gut-instinct guesses (although you’d be surprised how accurate these are when made by people with decades of experience). When talking with an engineer, we justify our methods using fancy words and pretty graphs and a confident tone, and a lot of that is legitimate, but some of it is BS and acting and we know it. Sometimes one of us says to the other about one of our equations; “Well, this seems to be working, even though it’s not really supposed to, so we’ll stick with it and tell the engineers to use it until someone complains”. (On the other hand, safety is one of the things we’re responsible for, and we take that very seriously. If there’s any chance that any of our equations could produce a product that could fail between inspections, then it’s “Stop everything!” until that is remedied).

    When talking amongst ourselves (or other experts), almost everyone in my group starts their observations, or their answers to questions, or their responses in a discussion, with “My understanding is…” or “What seems to me to be going on here” or “Maybe I’m missing something, but as I see it, …”. We know very well that the real world is much richer and full of traps than the equations we create for harnessing it. We know how easy it is to BS a bunch of people and say “This causes that, look at the numbers” when reality is actually much messier. When your job is developing models, you become well aware of how imperfect they are (despite being useful and safe).

    1. And what are we to deduce from that?
      (Makes mental note not to enter into any agreements or relations with Ultranaut in future)

  16. I bet there is an associated meta-effect. I would like someone to study whether or not people who have had the Dunning-Kruger effect explained to them are more likely to dismiss information contrary to their opinions. If your mind can just respond to anything difficult with “ah, its dumb people not knowing they are dumb again” it seems to be you’ve generated another source of cognitive bias by learning about this effect.

  17. Are we discussing confident ignorance or honest prejudice?
    Is there a difference?

    1. Sarah Palin? I thought Sarah Palin is an example of someone who realized when she was out of her depth.

  18. The lemon juice example seems more like a mental illness. That’s not stupid – it’s hallucinatory.

  19. I have two mottoes. The pertinent one on my coat of arms: “Often wrong; never in doubt.”

    The other: “If you can’t say something nice about someone, sit next to me.”

  20. I heard a report on the radio about this topic and then a couple days before or after there was another report about business executives. They studied the executives to see how they were different from the general populace. They found no significant differences in intelligence or any other traits they could measure except one: CONFIDENCE.

    If you put the two together, it goes a long way towards explaining why life in Corporate America is like Dilbert.

  21. I work as a Service Rep for a post-graduate educational testing company and I see this with our clients on a daily basis. Clients with exceptionally low scores on our test seem to think they have done wonderfully, while clients with higher-than-average scores always seem to think they should (or could) have done better. Low-scorers also seem completely baffled as to why their applications have been rejected by the schools to which they apply. I suppose there is something to be said for the old axiom “Ignorance is bliss.”

  22. I figured out a possible explanation of why the burgler thought what he did. You see, you use lemon juice to make ‘invisible’ ink…

  23. Finally! I found you, you! The smarts!
    Oh silly me! spending countless days by the Drudge Report, following their links only to find the same idiots ranting against -it seems sometimes- even gravity.
    God, this is awkward. -now I sit-
    OK, I feel dumb.
    I am depressed.
    Who the hell do you think you are, uh?

  24. I’m really darn sure that Newton’s laws of mechanics are a good predictive approximation of the behavior of physical objects. Does this mean I’m dumb.

    1. “I’m really darn sure that Newton’s laws of mechanics are a good predictive approximation of the behavior of physical objects. Does this mean I’m dumb.”

      It means that you have not yet learned about quantum physics and relativity. And once you learn about, someone will start telling you about string theory. And then you will realize just how little anyone actually knows.

  25. First there is a mountain. Then there is no mountain. Then there is.

    Any discussion of meta-effects, such as an individual’s ability to judge expertise in multiple domains? For example, someone who knows a great deal about physics, very competent in that domain: how does such a person judge their own competence in an orthogonal domain such as (to pick at random) Christian exegesis? (see, I can’t even spell it correctly)

    I suspect that we *all* fall prey to this effect… but I could be wrong. I’m often wrong.

    1. I’m glad someone brought this up. There have been studies that show that experts, even highly intelligent ones, tend to be extremely overconfident in their ability to solve problems outside their immediate domain of expertise. Given the prestige and influence on decisions that experts have, I would submit that this is a far more worrisome issue than the overconfidence of some random “dumb” people.

  26. Great! step 1 is done.
    Step 2 is to develop a cure in pharmaceutical form.
    Step 3 is to locate public water supplies.

  27. Whoa, weird internet flashback. My .sig for most of 2000:

    > “One puzzling aspect of our results is how the
    > incompetent fail, through life experience, to learn
    > that they are unskilled.” -Kruger & Dunning, Cornell
    > “Among 47 publicly traded e-commerce firms tracked
    > by Yahoo, only two are making money…” -L.A. Times

  28. I guess a corollary would involve the end result when people say things like, “I’m gonna…” I’m gonna quit smoking, I’m gonna get this done, whatever. When I hear somebody use “I’m gonna” I can be pretty sure it ain’t gonna happen. Of course, another parallel is Richard Wiseman’s study of luck. According to his experiments people who are more sure of their own luck tend to be luckier. I won’t go into definitions of the “L” word.

  29. The article was ruined by that last paragraph. I wonder if the irony of having confidence in the examples when explaining about underestimation was lost on them.

    I Don’t mean to comment anonymously; it’s just faster.


  30. What amazes me is that science didn’t have a name for this phemonenon until 1999. Confident fools are the most destructive force in nature.

  31. “Ignorance more frequently begets confidence than knowledge” —Charles Darwin—
    That’s great for use as a sig line, especially when making bold assertions outside of the areas of my expertise. Elsewhere of course, don’t worry.

  32. I can’t believe no one has mentioned Will Ferrell. He has built his whole career playing characters full of undeserved ego. That’s why his George W. is so spot on.

  33. “Debates on climate change, the age of the Earth or intelligent design are perfect real-life examples of the Dunning-Kruger effect. It beautifully explains the utter confidence of those who, with no expertise, remain stubborn in their views regardless of overwhelming evidence.”

    Which way is the overwhelming evidence pointing to the causes of the current climate change trends versus changes that occurred in the past? I think Dunning-Kruger encourages us to not be overconfident one way or the other, while the generally theory of epistemology suggests we should be quite conservative in our approach to ecology, to avoid wiping out our species.

  34. I think this whole theory can be summed up in one sentence:

    “Most people grade themselves an A.”

    In some cases, like the humble genius that forms the twist on this useless theory, people are ranked “A+” relative to their peers.

  35. I am fairly convinced I’m getting dumber as I age, and it’s scaring me because I’m only 35.

    It’s nice to imagine it’s this effect, but I don’t think it is. :(

  36. I am reminded of the vilification of ‘professional management’ that was in vogue about this time last year. For my part, I believe that professional management is the institutionalization of this effect.

    In particular I remember footage of a class taught at a top-flight management school(Harvard i thynk)wherein the ‘managers’ were taught to make snap decisions and refuse to budge to evidence; also a class in which ‘lawyers’ were taught to make credible sounding noise in defense of briefs they had not read. I came away from these revelations thinking about the Guillotine.(i may be harboring a bit of ‘hostility’)

    I am forced to agree with those who assert that this wisdom is both old and ubiquitous among the wise in any time. I will not be calling it by the names of these two researchers unless it is a rhetorical requirement in an argument. They taught me this in Sunday school; I learn it again and again as I study philosophy; As I argue with my drunk friends I get the lesson trod deeply across my floors.

    There are dimensions to this which we are not noticing. This is why I am nonplussed at this new ‘research finding'; to me the drive for overconfidence is connected with sex more than with competence at work. I believe that we have allowed these to become conflated and we will now suffer a decline as a result. When the whims of every person matter according to the noise they make, sex swamps out all things in importance. In that instance, cocksure is the *right* thing(right ladies?)and in a society that cares about nothing but sex we can expect the thoughtful to be edged out of positions of power.

    1. Fair point.
      We should perhaps all pay a little more attention to framing debates in ways that:
      a) minimise ad hominems and “loss of face” when someone adopts a position that the vidence doesn’t support
      b) make people look good when they show they’re willing to be swayed by evidence, as opposed to “point scoring” for a pre-chosen position.
      Neither of those things are easy. Consensus seeking is hard, and many “science” type question do not lend themselves to consensus seeking, but have a right and a wrong answer. That’s even harder to keep non-adversarial.

  37. Some of this seems quite reductive, though. Aside from improving his golf game, what reasonable reason would Tiger Woods have to doubt his preeminence? If you’re good at something, part of this is a rational evaluation of why and how you’re good: in this case, excess doubt for doubt’s sake is less an openended intellectual inquiry or humility than needless worrying, no doubt occasioned by some other unresolved issue.

    Doubt seems like a useful heuristic for self-evaluation and for further learning: but I’ve yet to see a talented person who overindulges in doubts about their competence, skills, etc. work either very happily or well. A reasonable and hard-earned confidence is a gift to oneself, and to others: it allows us to be productive and joyous, two not-bad things in this difficult world.

  38. The next time someone tries to offer you a solution to a hard problem, listen for his/her use of the word “just”. As in “Just do X” or “First do Y and then it’s just a matter of Z”. 90% of the time, use of “just” is a clear indication of speaker ignorance. The other 10%, the person actually has the necessary experience to recognize the solution. There doesn’t seem to be any middle ground.

  39. The really interesting thing to me about this article isn’t that this effect exists, but the fact that my husband just recently (as in within the last 2 weeks) started an email thread conversation among several of our friends about THIS VERY SUBJECT.

    Now, what in the world could be going on in the United States that would cause a bunch of us to suddenly be discussing the “stupid smart people” syndrome?

    Hmmmmm…I wonder…

  40. Doesn’t ‘Dunning-Kruger’ sound like a Victorian firearm? If I ever write a steampunk novel, that’s the make of weapon my protagonist is going to carry.

  41. The real problem is that ignorant people are so confident that they should procreate.

  42. Confident enough to believe that it’s appropriate to steer this thread to an argument about US politics, dumb enough to believe that I wouldn’t remove the threadjack: priceless.

      1. Did you come here looking for objective reporting of the facts? It’s a blog. They can have an opinion. They make no claim to be an objective news source.

        You know who does? Fox News. They claim to be an objective news source. That is their claim. Fair and balanced.

        How do you think they are performing on that claim? Why not tell them? Let us know how you go.

      2. First, form and content are not the same thing.

        Second, they’re both regarded as inarticulate, barely-educated idiots by virtually everyone except their US partisans.

        Third, there’s a difference between citing individual examples of idiocy and lobbing epithets willy-nilly at democrats/republicans/liberals/conservatives.

  43. It’s (barely) similar to how only crazy people get actually angry and defensive when you call them crazy.

  44. 1. Agree with #35. The lemon juice anecdote is an example of delusional thinking, and I’m kinda surprised they used it.
    2. If I had a band, I’d call it The Dunning-Kruger Effect.
    3. (Maybe Dunder Mifflin effect?)

  45. I do feel as if something like this is happening, but post 20 definitely made me think–if most people of whatever competence level thought they were around the 2nd quadrant, doesn’t this just say that confidence is fairly constant, largely unrelated to competence one way or another?

    Even if it’s a real effect, it’s still a statistical thing. There can still be modest ignorant or incompetent people, and self-confident people with ability. And it might be domain-related. But maybe not entirely–perhaps people who have been trained in logic and critical thinking make more accurate assessments of their expertise across domains?

    I remember reading about an odd related thing, not about self-assessment but assessment of other people. In one of the books that were the basis for the TV series “All creatures great and small”, the veterinarian main character noticed that everyone seemed to have more confidence in the skills of people with sort-of-related expertise than in the skills of people actually in a particular field. So people would take the advice of the guy who made a living hauling away dead farm animals over the vet’s opinion about sick animals. But they’d accept the vet’s opinion over a real doctor’s opinion about human diseases!

  46. Let’s not forget about the “educated-beyond-my -level-of-common-sense-and-insulated-from-reasoning” effect. A good example of this is when someone says to themselves “this guy believes in Intelligent Design? What a moron! I, with my superior education and intellect, would never subscribe to such ridiculous notions!” Also known as arrogance

    1. A good example of this is when someone says to themselves “this guy believes in Intelligent Design? What a moron! I, with my superior education and intellect, would never subscribe to such ridiculous notions!” Also known as arrogance

      A good example of this is when someone says to themselves “this guy believes in Santa Claus? What a moron! I, with my superior education and intellect, would never subscribe to such ridiculous notions!” Also known as intelligence.


  47. A good example of this is when someone says to themselves “this guy believes in Santa Claus? What a moron! I, with my superior education and intellect, would never subscribe to such ridiculous notions!” Also known as intelligence.

    My point is made…this ones arrogance is telling (:o

    1. My point is made…this ones arrogance is telling (:o

      Sorry, if not believing in bullshit and/or being agnostic is arrogance then I’ll remain guilty as charged. I don’t subscribe to ridiculous notions no matter how politically correct and/or universally accepted they may be. At least I’m in good company.

      “The idea of a personal God is quite alien to me and seems even naive.” – Albert Einstein

  48. Two thoughts (maybe relevant):
    1. The concept of “the heresy of the answer”. (Wisdom is in the search. As soon as you “know the answer”, you’re wrong.)
    2. We’re all ignorant, just about different things. ( – Will Rogers)

  49. We have this problem in higher education as teachers. Our students can fail the course proving their inability to master the material, and then they are able to rate the instructors ability to teach it—-how accurate would these ratings be? This all occurs within a class where there are 4-5 people who got above 90% listening to the same lecture, doing the same assignments, and taking the same exams. Those of you in college who find this effect interesting should ask yourself if this is fair for your teacher to be judged this way and if you would feel that such a system is fair for you to be judged within. Be ready: in the world outside you will be judged this way after you graduate and get a job.

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