
The Dunning-Kruger Effect may not be a common term you’d hear over the dinner table or on the news, but it’s a phenomenon that you’re sure to have encountered, whether it’s at work, at a family event, or on TV. In fact, it’s something that’s been written about time and again — from as far back as the time of Confucius, to Charles Darwin’s The Descent of Man.
But what is it? It’s an effect coined by psychologists David Dunning and Justin Kruger, who found in their experiments that people who aren’t very good at something tend to believe that they are way better and smarter than they truly are. In other words, it’s when people who aren’t very competent mistake themselves as being very competent, precisely because they don’t know enough about it to know that they’re incompetent.
Although the name wasn’t coined until 1999, the Dunning-Kruger Effect is something that Darwin pointed out in 1871 when he wrote, “Ignorance more frequently begets confidence than does knowledge.”
Shakespeare understood it too when he wrote, “The fool doth think he is wise, but the wise man knows himself to be a fool,” in 1623’s As You Like It. Even Confucius did too between 500 and 400 BCE, when he wrote, “Real knowledge is to know the extent of one’s ignorance.”

In truth, the term provides a common name for something many of us know from experience: That though some people doubt themselves and their abilities even when they’re objectively good at something, many others are often blind to how they may be objectively bad at it — yet are often way more confident than those who are competent.
On Cognitive Biases, Competence, and Confidence
The Dunning-Kruger Effect is a type of cognitive bias, which is like a blind spot for your brain. We perceive the world around us through a filter of our experiences and preferences, and so our subjective reality may not always align with the truth.
The Study
The original research by Dunning and Kruger, published in the Journal of Personality and Social Psychology, tested participants’ real and perceived ability in three areas: humor, logical reasoning, and English grammar. After answering a test, which indicated their real ability, the participants were then asked to rate their own performance, which relates to their perceived ability.
Participants who scored the highest and the lowest in the English grammar test were also asked to come back and evaluate their peers, to see whether they are able to recognize competence (or incompetence) in themselves or others.
A fourth test on logical reasoning was also conducted, with half of the participants being given some training on logical techniques that would help in the test they just finished. Then, all participants were asked to review their finished exam, and to gauge whether they did well.

Across these four rounds of study, the authors found three things.

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- Participants who scored lowest were vastly overconfident about their test performance. Those in the bottom of the test rankings tend to think of themselves as belonging to or near the top, while those who did really well tended to underestimate their scores.
- Those who were not competent tended to inaccurately assess other people’s competence, too. Those who scored in the bottom of the English test, for instance, didn’t realize their mistakes even when they were shown the better answers of their more competent peers, thinking themselves to still be among the top test-takers. Meanwhile, those who scored higher in the tests but initially rated themselves low relative to their peers were able to improve their self-appraisal after being shown the tests of others.
- Improving participants’ skills can help them realize their previous errors and recalibrate how they thought about themselves in relation to others. Those who were given logical training after taking the logic reasoning test were more able to judge their performance realistically.
Why Does It Happen?
The tendency of the least skilled to overestimate their capabilities boils down to what psychologists call metacognition. This entails thinking about your own ways of thinking and evaluating your own knowledge of something (or lack of it). By taking a step back and examining yourself objectively, you’re more able to see the bigger picture and understand how you understand information and why you think or act in a certain way.
Unfortunately, those who exhibit the Dunning-Kruger Effect lack metacognition — experiencing instead what David Dunning calls meta-ignorance: They’re ignorant about their own ignorance.
From this limited and highly subjective point of view, they may see themselves as more skilled, more knowledgeable, and ultimately, superior to others.
In contrast, those who are very skilled or competent are better aware of the whole landscape of their discipline, including their specific area of expertise and what they might not know much about.
A simplistic example would be a child who has just mastered the multiplication table. They may think they know everything about multiplication and mathematics but are (blissfully) unaware of entire branches of mathematics they have yet to learn, like statistics, calculus, and geometry.
On the other hand, even experienced statisticians might have to turn down certain clients or projects that they may not have enough knowledge about, with many specializing in distinct areas like bioinformatics or econometrics.
The Dunning-Kruger Effect is one explanation for why some of the most incompetent people you know are also the most confident: They simply do not know what it takes to be good at something and think of themselves already at that level.
The First Rule of the Dunning-Kruger Club
The first rule of the Dunning-Kruger Club, David Dunning explains in a 2019 interview, two decades after the original study, is that “you don’t know you’re a member of the Dunning-Kruger club.”
As it turns out, it’s a pretty big club. The Dunning-Kruger Effect has been studied repeatedly in the years since.
In one study, for instance, Dunning and his fellow researchers mixed made-up terms with legitimate jargon from disciplines like biology, geography, physics, and politics. 9 out of 10 participants claimed they knew at least one of the fake terms, and the more familiar with a topic participants claimed to be, the more likely they were to say they knew the non-existent terms.

Other studies found similar patterns of overconfidence among the less competent in terms of emotional intelligence, financial literacy, GMOs, and even wine knowledge.
Sadly, the effect can also play into wider social beliefs. For instance, Dunning and Ehrlinger found that though women did just as well on a science quiz as men, they’re more likely to underestimate their performance, believing the myth that women have less scientific abilities than men.
At the individual level, the Dunning-Kruger Effect can have a profound impact on people’s beliefs, and decisions. It causes a “double-curse.” People who are less skilled or capable aren’t self-aware enough to know they are less skilled or capable — and thus, they’re less likely to seek out opportunities to learn and grow.
At the societal level, this effect highlights even bigger problems. The Dunning-Kruger Effect has been observed in anti-vax movements and among people who mistakenly think they’re good at spotting fake news. It’s also why none of us are completely immune to propaganda.
It doesn’t help, of course, that we often associate confidence with competence, both for ourselves and with others.
Is It Happening to You?

We all know a president who, for all their bravado, doesn’t know what they’re talking about, or perhaps a distant relative who thinks their five-minute YouTube search is more valid than decades of mRNA research and development.
But the truth is, the Dunning-Kruger Effect can happen to you, too. No matter how informed or experienced we try to be, there will always be areas or topics we know nothing about, and it’s an all-too-common mistake to think our expertise in one area might carry over into another.
This, David Dunning explains, is one of the most common misconceptions about the Dunning-Kruger Effect. “They think it’s about them. That is, there are those people out there who are stupid and don’t realize they are stupid,” he says. “The work isn’t about that.”
What it is about is how this effect can happen to everyone — it’s just that, according to David Dunning, “Some of us are a little more flamboyant about it.”
Not knowing how ignorant we are about certain things is part of being human. Our brains are designed to look for patterns or take shortcuts, and this leads to errors and cognitive biases like the Dunning-Kruger Effect.
It isn’t necessarily a sign of low intelligence, and in fact, smart people can also fall into the same trap of thinking we’re better than we truly are. Thus, it would do us well to try and see this in ourselves as quickly as we might point it out in others.
How to Avoid Falling Into the Trap
A good starting point is to learn more about the Dunning-Kruger Effect, and to try recognizing it in your own thoughts and actions. The 1999 study also points us to some useful steps.

For instance, learning more about a topic or area of study can help us better identify what it is we don’t know yet. Take your time and be patient with yourself — rushing into snap decisions is one easy way to fall into the trap of overconfidence. There’s also a lot of power in awe, which researchers explain can help us get excited about pondering the unknown.
Next, try to challenge your own beliefs and knowledge. It’s easy to pay attention to things that confirm your existing assumptions, but a healthier and more challenging habit is to take on the role of devil’s advocate with yourself. Ask: Is there a counterargument to your existing ideas? Maybe there are other ways to approach things that can help you grow?
You can also lean on others. Even though it might be difficult or uncomfortable, ask for constructive criticism. An outside point of view can give you valuable insights into your own blind spots. You don’t have to accept all of it by default, of course. For claims you don’t agree with, try to ask for examples or ways you can still improve.
Lastly, examine your own self-beliefs. Maybe you’ve always thought of yourself as a logical thinker or a patient friend. These things may still hold true, but there’s also a chance that they won’t — and clinging to those beliefs can keep us from improving for ourselves and others. This can be quite difficult, but letting those self-beliefs be tested and scrutinized can only be even more empowering once you’re more aware of your own strengths and weaknesses.
Knowing What You Don’t Know
Everyone experiences the Dunning-Kruger Effect. Left unchecked, it can affect how we behave and make everyday choices. Though it is infinitely easier to identify it in others, the challenge for us is to be able to identify it in ourselves.

David Dunning and Justin Kruger explain that though your confidence will decline to more realistic levels once you’re made more aware of your own shortcomings, you will gradually earn your confidence back as you give yourself enough time and space to improve. And this, I think, is one source of hope.
After all, though it might be stressful to accept we’re not as good as we think we are, it can also be rather exciting. There is so much out there that we can still learn, and there is so much room for us to grow — we just need to let curiosity, honesty, and openness lead the way.