Have you ever encountered people who were eager to explain or do something that they did not understand, if you look at the situation soberly? Maybe you have been in their shoes? The main culprit here is the Dunning-Kruger effect. What is the essence of this cognitive distortion? How does it manifest itself in ordinary life? And what should be done to avoid becoming its victim?

The Dunning-Kruger effect might not have been discovered if not for an anecdotal story that took place in Pittsburgh in 1995. One MacArthur Wheeler and Clifton Johnson robbed two banks in broad daylight with unprecedented audacity. The criminals vigorously waved their weapons under the noses of tellers, not caring at all about disguising their faces or hiding from the cameras. Naturally, the robbers were quickly arrested.

When Wheeler was shown the security camera footage, he was shocked and could only mutter, “But I had juice on me!” It turned out that Wheeler had been misled by his accomplice. Johnson had told him that if he put lemon juice on his face, it would not be visible on the film. To use an invisible ink analogy, if you write something on a piece of paper with lemon juice and then warm it with a lamp or iron, the words will come out. Wheeler later admitted to the police that before the robbery he had conducted an experiment: he smeared himself with juice and took a Polaroid photo. The photo really didn’t show his face. Apparently, the camera was defective, which cost the hero of this story his freedom.

Wheeler’s case would have remained just an amusing case study of criminal behaviour had it not been accidentally heard on TV by David Dunning, a professor of social psychology at Cornell University. The latter came up with the idea that “if Wheeler was too stupid to be a bank robber, perhaps he was also too stupid to realise that he was too stupid to be a bank robber.” In other words, the criminal’s stupidity prevented him from realising that he was incompetent.


Along with his graduate student Justin Krueger, Dunning set out to study this phenomenon. They conducted an experiment: they asked students questions about grammar, logic and humour, and then asked them to rate their own answers. As a result, the participants with the lowest grades thought they did better than the rest of the class. And vice versa: students with the best answers were sure that they did worse than they actually did.

Dunning and Krueger concluded that amateurs tend to overestimate their skills. Without seeing the whole picture, they simply cannot adequately evaluate themselves. And really smart people often underestimate their knowledge: they think that if a task is easy for them, then it is probably not that difficult. This is the so-called impostor syndrome, when our achievements seem to us not as a result of our labour or knowledge, but as a consequence of luck or external help.

You exceeded the plan at work – just lucky, the teacher gave you an A – you were in a good mood

However, it is wrong to think that the Dunning-Kruger effect divides people into smart or stupid. Gifted people with high intelligence also overestimate their skills in an unfamiliar field. A mathematical physicist may mistakenly think he is brilliant at geopolitics, while an experienced doctor may think he is brilliant at building dams.

Of course, the effect itself existed before Dunning and Krueger. Long before the studies described above, scientists and philosophers were talking about it. Suffice it to recall Darwin: “Certainty is more often produced by ignorance than by knowledge. Or Bertrand Russell: “One of the unpleasant properties of our time is that those who have confidence are stupid, and those who have any imagination and understanding are filled with doubt and indecision.”


The notorious effect can be observed in almost all areas of human life, from sports to driving. For example, according to statistics, people with little driving experience, but not those who have just passed their driving licence, are more likely to get into accidents on the road – this is reported by the RG portal with reference to the Russian traffic police. Most of those who have recently said goodbye to the status of a pedestrian, are afraid of busy traffic and for a year observe extreme caution. Then, for two or three years, beginners feel like master drivers. It is only in the fourth year of driving that they can objectively assess their skills.

It can also be observed among the participants of various talent shows: from novice stand-up comedians to dancers and singers. When they see the jury’s low scores, they get upset, perplexed and only later realise their real level.

And you have probably seen this very effect in the gym many times: beginners often try to lift much more weight than they can actually do. Perhaps you yourself have been in the shoes of a person who put a couple of extra pancakes on the bar and as a result could not do a single approach.


To avoid falling victim to this cognitive distortion, you need to study and practice. The more knowledge you gain on a topic, the better you will realise how much there is still to learn. The learning process can be depicted on a graph: knowledge and experience is the horizontal line and confidence is the vertical line.

When we are just starting to master an area, our confidence grows much faster than our actual knowledge. At some point it reaches a maximum – this point is called “Peak Stupidity”. Some amateurs, by the way, stay at this point for life, thinking they are experts. As one goes deeper into the details, the clever person discovers the true extent of his incompetence and sinks into what is called the “Valley of Despair.” This is the point at which the temptation to abandon the endeavour is greatest: for example, after six months of learning a foreign language, you realise how much you don’t know and you sink into despondency.

The good news is that if you get over the minor and pull yourself together, from this point you will confidently go up the chart – to the “Slope of Enlightenment”. This is the stage when you are already quite experienced and knowledgeable, can really assess your level and realise what you still have to work on.