Some years ago, I started taking house-dance classes. (House is a specific style of dance that goes well with house music.) For more than two decades, I’d been dancing at raves and parties, where people complimented me and sometimes even asked if I was a professional. While I didn’t know what to expect at the studio, I had reason to think I might not be terrible. I immediately found myself the dunce in the back of the class. I hadn’t known what I didn’t know.
My experience demonstrated what’s known as the Dunning-Kruger effect, an often-cited and still-debated concept in both psychology and popular culture.
In 1999, David Dunning, a psychologist then at Cornell University, and Justin Kruger, a Cornell graduate student, published a seminal paper called “Unskilled and Unaware of It.” The paper described four experiments testing college students on humor, logic, and grammar. Dunning and Kruger also asked participants to guess their scores, in both absolute and relative terms. The key finding that kept popping up: Those in the bottom quartile of performance wildly overestimated their skill in that domain (in some studies rating their percentile, on average, around 60 when it was around 10). A smaller finding: Those in the top quartile often underestimated their relative skill (though to a lesser extent).
Dunning and Kruger theorized that the skills needed to perform overlapped with those needed to judge performance, and so poor performers lacked the metacognition to see their failures. Combine that with a universal “better-than-average effect,” in which people overestimate their abilities compared to other people, and the worst performers overestimate the most. Meanwhile, high performers also think they’re better than average but underappreciate the extent to which they are, because of the “curse of knowledge,” in which we think our knowledge is universally shared.
It’s not often that an academic paper finds its way into mainstream culture, but when it does, it’s often misunderstood. I recently contacted Dunning, now at the University of Michigan, to talk about the effect’s legacy. He still vigorously defends the idea, while exploring new manifestations, and has even turned the term into an adjective. As Dunning says, we are all “Dunning-Kruger” at some point in our lives.
What was the origin of your 1999 paper?
Well, the research focus I’ve had off and on is: How well do people know themselves? And just through personal observation, of students in my office, faculty meetings, watching C-SPAN, I would notice that people would say—how should I say it diplomatically?—outrageous things. They have to know what they’re saying can’t be true. I’ve had students come into my office to graciously allow me the chance to concede that the answers I designated as right on the test were wrong.
In his first year of graduate school, Justin Kruger said he wanted to work with me. I said: How much do people know that they’re getting something wrong? And so, we did these studies to see how much people who were performing very poorly on tests were aware of it. We tested logic, grammar, and whether people could spot funny jokes? The first data set that came in was a revelation. I was absolutely astonished. Of course, people are going to overestimate themselves, but we didn’t realize it was going to be at that magnitude.
Others had found that ignorance leads to overconfidence—in physics, chess, tennis, reading, driving, socializing. What was the new piece here?
I think the new piece was putting numbers to it, and putting the formal psychological analysis to it, this distinction between cognition when making a judgment and metacognition when judging the judgment.
Do you think of the effect as just the overconfidence of people who are unskilled or also the underconfidence of people who are highly skilled?
There was a long literature about the “curse of knowledge” for people who are very knowledgeable. This is why doctors are terrible communicators. They think you know where the kidney is. They think you know that this drug has cardiac implications.
Do you consider that part of the Dunning-Kruger effect?
I’m going to say no. By the way, we didn’t name it the Dunning-Kruger effect. Someone on the internet years later started talking about the Dunning-Kruger syndrome and then threw up a Wikipedia page. A lot of people just say the effect is that people at the bottom don’t know they’re at the bottom. Period, end of story. But it’s also the mechanism that connects those two failures.
What’s a striking example of Dunning-Kruger today?
AI is the most interesting. The first obvious question is: Do chatbots experience Dunning-Kruger? And the answer is: Oh, yeah. Except for some exceptions, they don’t know when to hold back due to uncertainty. There was a game recently where you make up a phrase and ask a chatbot what it means, and it would give you an answer instead of saying it didn’t know. The other question is: Do chatbots give people Dunning-Kruger? One group found it reversed Dunning-Kruger and made the best performers even more overconfident than the worst people. There’s also work showing that people are very Dunning-Kruger in terms of their ability to tell fake news from real news.
In other work, one professor allowed students to buy insurance if they felt they were going to be in the bottom 50 percent of the class, but very few did. So, misestimations lead to behaviors that don’t work very well. Others have shown that people who are most likely to dismiss scientific consensus are those who know the least science but have the most confidence in their knowledge of the science.
Read more: “Why Do People Believe the Earth Is Flat?”
Do you think AI sycophancy, in which chatbots flatter their users, might heighten the Dunning-Kruger effect?
Yes. One of the reasons why people are overconfident in general is that they tend to look for reasons supporting their ideas. In fact, one of the pieces of advice we always give is: If the decision is important, stop and ask why you might be wrong. In planning, one of the procedures that’s recommended for a group is to project yourself into the future and imagine your initiative failed spectacularly. What happened to make it fail? And say, “OK, what can we do to prevent those stories from happening?” That’s called a “pre-mortem.”
Doctors do this as a matter of course. They have a different name for it. They don’t diagnose you; they do a “differential diagnosis.” They may have an idea, but they have to think about what else it can be. OK, you might have Lyme disease, but what else are your symptoms consistent with? We’re going to test you to rule out everything that we can. That’s core to medicine, thinking of alternatives, thinking how you could be wrong.
Your 1999 paper mentioned “motivational biases”: People are scared to look for ways that they might be wrong, or to think of themselves as stupid. Do you think acknowledging that there are multiple intelligences or multiple skills might allay people’s fears of being generally stupid, and might make them more receptive to negative feedback about the specific areas in which they’re unskilled?
Absolutely, yes. Because first off, Dunning-Kruger is not about being stupid. Dunning-Kruger is about everybody. Each of us is Dunning-Kruger sooner or later. Some of us have more spectacular stories to tell, but every one of us has pockets of incompetence. It’s not about being stupid; it’s about being careful and wise. And the other thing is that you are a person who grows and changes. So what you want to do is set yourself up for success.
I heard someone use the Dunning-Kruger effect to explain that people who opposed his political beliefs were too stupid to know that they were wrong. Have you seen other people make claims like that? And is it more likely that that is true, or just that people are motivated by different ideologies?
Well, people can be stupid, but people can be motivated by ideology. I wish people would stop yelling Dunning-Kruger at each other. We offered the paper as a reason to self-reflect. I remember when I started looking at Twitter back in the day and seeing people yelling, “You Dunning-Kruger idiot” at everybody else. I went, “Oh no.” My biggest regret is that it’s become an epithet to hurl at other people. It’s something to hurl at yourself every so often.
How can we check our blind spots?
The best way to do it is with other people. Now, they have to be brave, and they have to tell you that you’re wrong. And I wish we were more skilled at being able to tell each other when we have blind spots.
Is overconfidence ever good?
Confidence isn’t bad. Confidence is something to be managed, and there are times you really want to be confident. In preparation, you don’t want to be overconfident. You want to be, if anything, underconfident, and overprepare. If you’re going into battle, or if you’re going to the Olympic Games, you definitely won’t just go, “Nah, I won’t practice today. I won’t train. I’m going to get the gold.” But on the day that you’re executing, you do want to be supremely confident, because it’ll have a payoff.
When should we most worry about the Dunning-Kruger effect?
When there’s a lot of overlap between performance and judgment. In logic, they’re practically the same thing, but not in sports. I know I’m a horrible golf player. I can tell because the trees tell me when my ball travels to the right and lands in the poison ivy. Also beware lack of exposure to outside models. I thought I was a pretty good cello player, until I heard a recording by Jacqueline du Pré, and I went, “I didn’t know you could do that with this instrument.”
There’s some research showing that people are overconfident on hard tasks and underconfident on easy tasks.
Right. Confidence is always going to be moderate to high, because you’ve come to the best answer you can come to. On hard tasks, you’re probably not going to get to the right answer, and on easy tasks, you’re always going to get to the right answer. Still, we’re always consigned to be moderately confident in the decisions we make. We make a decision and that’s what we’re going to do. We’re captives. No one, except for George Costanza in Seinfeld, says that whatever they were going to do, they will do the opposite. No one ever does that.
Over the years, there have been critiques of the Dunning-Kruger effect, namely that it boils down to the statistical phenomenon of “regression to the mean.” [If you take two noisy measures (in this case, someone’s skill and someone’s estimation of skill), and the first is extreme (very high or very low skill), the second will necessarily trend toward the middle. As a result, the incompetent appear to overestimate and the competent appear to underestimate.] What do you make of this criticism?
It ignores the literature on how you correct for regression to the mean. There are many standard ways to correct for it, from epidemiology, economics, and psychology. It dampens the effect only a little.
There are other methodological issues. In one example, the researchers asked people to rate their intelligence on a 1 to 25 scale after taking an IQ test. They then assumed that people rating themselves as a “25” thought they had a 160 IQ and those a “1” thought they had a 40 IQ. Those are pretty big assumptions. I wouldn’t put those thoughts in people’s heads. And I also wouldn’t ask about an ability as broad as intelligence, which means so many different things to different people.
In another example, the data turned out to be beautiful support for our original framework, although I cannot figure out how the authors couldn’t see it. They statistically separated the ability to judge a performance from the ability to produce a quality performance and found that high performers were no better at judging their performance than those at the bottom. So, they said, we were wrong. However, before the separation, high performers were better at judging, because expertise aided both performance and judging. That last part is exactly what we said in our original 1999 paper creates the effect. In real life, there is no separation. Their data are exquisite in making our point.
Read more: “Why You’re Biased About Being Biased”
Has your understanding of the effect evolved?
I’m beginning to see more implications of the idea that we live in a bubble of our own knowledge. Lately, we’ve done work showing that experts are better able to tell when they’re making a right decision versus a wrong decision. But there’s a twist. When they’re wrong, they’re even more confident that they’re right than novices are. We see this again and again.
Experts’ being more confident than non-experts that they’re right when they’re wrong seems to go against the Dunning-Kruger effect.
On aggregate, experts are better at being right, and at knowing when they’re right. But experts have to be aware that being highly confident is not necessarily a guard against being wrong.
Is that what’s sometimes called “Nobel disease,” where Nobel Prize winners will espouse on topics that they don’t know much about?
Nobel disease is actually a different syndrome, also called “epistemic trespassing.” That was just everywhere during the pandemic. People started opining about vaccines and epidemiology, and they had no business doing it, but, “Hey, you know, I have a Harvard degree, so that’s good enough.” A lot of people’s beliefs of their competence come from these soft cues they have about themselves. That’s not knowing your circle of competence. It goes to a fever pitch when you have a Nobel.
This is about the geography of being “an expert.” Do they know the boundaries of their competence? We just published a paper showing that if people start taking classes on a topic like psychology and law, they start thinking they know stuff they can’t possibly know. At the end of a psych and law class students will say, “Yep, I know this psycho-legal concept.” They also say they know other concepts that we asked about but were never mentioned in class. And they weren’t mentioned in class because we made them up. The boundary line between what you know and what you don’t know is fuzzy. It’s a profound thing of being human that we live in a bubble of our own experience. 
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