The Dunning-Kruger Effect, or: The Illusion of Confidence

Head-on car accident. Rural South Dakota, 1932. Photo: Wikimedia.

What know-it-alls don’t know, or the illusion of competence

One day in 1995, a large, heavy middle-aged man robbed two Pittsburgh banks in broad daylight. He didn’t wear a mask or any sort of disguise. And he smiled at surveillance cameras before walking out of each bank. Later that night, police arrested a surprised McArthur Wheeler. When they showed him the surveillance tapes, Wheeler stared in disbelief. ‘But I wore the juice,’ he mumbled. Apparently, Wheeler thought that rubbing lemon juice on his skin would render him invisible to videotape cameras. After all, lemon juice is used as invisible ink so, as long as he didn’t come near a heat source, he should have been completely invisible.

Police concluded that Wheeler was not crazy or on drugs – just incredibly mistaken.

The saga caught the eye of the psychologist David Dunning at Cornell University, who enlisted his graduate student, Justin Kruger, to see what was going on. They reasoned that, while almost everyone holds favourable views of their abilities in various social and intellectual domains, some people mistakenly assess their abilities as being much higher than they actually are. This ‘illusion of confidence’ is now called the ‘Dunning-Kruger effect’, and describes the cognitive bias to inflate self-assessment.

To investigate this phenomenon in the lab, Dunning and Kruger designed some clever experiments. In one study, they asked undergraduate students a series of questions about grammar, logic and jokes, and then asked each student to estimate his or her score overall, as well as their relative rank compared to the other students. Interestingly, students who scored the lowest in these cognitive tasks always overestimated how well they did – by a lot. Students who scored in the bottom quartile estimated that they had performed better than two-thirds of the other students!

This ‘illusion of confidence’ extends beyond the classroom and permeates everyday life. In a follow-up study, Dunning and Kruger left the lab and went to a gun range, where they quizzed gun hobbyists about gun safety. Similar to their previous findings, those who answered the fewest questions correctly wildly overestimated their knowledge about firearms. Outside of factual knowledge, though, the Dunning-Kruger effect can also be observed in people’s self-assessment of a myriad of other personal abilities. If you watch any talent show on television today, you will see the shock on the faces of contestants who don’t make it past auditions and are rejected by the judges. While it is almost comical to us, these people are genuinely unaware of how much they have been misled by their illusory superiority.

Sure, it’s typical for people to overestimate their abilities. One study found that 80 per cent of drivers rate themselves as above average – a statistical impossibility. And similar trends have been found when people rate their relative popularity and cognitive abilities. The problem is that when people are incompetent, not only do they reach wrong conclusions and make unfortunate choices but, also, they are robbed of the ability to realise their mistakes. In a semester-long study of college students, good students could better predict their performance on future exams given feedback about their scores and relative percentile. However, the poorest performers showed no recognition, despite clear and repeated feedback that they were doing badly. Instead of being confused, perplexed or thoughtful about their erroneous ways, incompetent people insist that their ways are correct. As Charles Darwin wrote in The Descent of Man (1871): ‘Ignorance more frequently begets confidence than does knowledge.’

Interestingly, really smart people also fail to accurately self-assess their abilities. As much as D- and F-grade students overestimate their abilities, A-grade students underestimate theirs. In their classic study, Dunning and Kruger found that high-performing students, whose cognitive scores were in the top quartile, underestimated their relative competence. These students presumed that if these cognitive tasks were easy for them, then they must be just as easy or even easier for everyone else. This so-called ‘imposter syndrome’ can be likened to the inverse of the Dunning-Kruger effect, whereby high achievers fail to recognise their talents and think that others are equally competent. The difference is that competent people can and do adjust their self-assessment given appropriate feedback, while incompetent individuals cannot.

And therein lies the key to not ending up like the witless bank robber. Sometimes we try things that lead to favourable outcomes, but other times – like the lemon juice idea – our approaches are imperfect, irrational, inept or just plain stupid. The trick is to not be fooled by illusions of superiority and to learn to accurately reevaluate our competence. After all, as Confucius reportedly said, real knowledge is knowing the extent of one’s ignorance.

Kate Fehlhaber

This article was originally published at Aeon and has been republished under Creative Commons CC BY-ND 4.0.

The Myth of Sisyphus

The Myth of Sisyphus by Albert Camus

My rating: 3 of 5 stars

Camus gives words and thoughts and theories and literary examples to my own primitive discoveries about work and suicide. I remember waking one morning, at age 19, and thinking: "If this is all my life will ever be, then today I must either change it or end it". If I had to roll that rock up the hill one more time then that was it for me. I don't write this gratuitously or intend to treat suicide glibly, but in the context of Camus' "philosophical suicide", my experience of the absurd has informed much of my philosophy for living. I have often thought that if God does not exist, then there is no point in living. Camus twists around varieties of my thoughts, but he does so referring particularly to Nietzsche (that most famous of God's "assassins") and antitheses of my understanding. This is a short book and it seems to be an abridged version of a much larger work. Nevertheless, it is sufficient to point out a number of my reading deficits. This may require a second reading once I complete Kafka's The Castle, and much of Nietzsche. Camus broaches many topics that tend to be completely avoided by almost any person to whom I have ever spoken. It would seem that once again Continental philosophers have a monopoly on saying what everyone is thinking but were too afraid to say. Two quotes resonated with me:

On the futility of suicide, from p. 6:

I have heard of an emulator of Peregrinos, a post-war writer who, after having finished his first book, committed suicide to attract attention to his work. Attention was in fact attracted, but the book was judged no good.

And on death as a work in progress, from p. 111:

If something brings creation to an end, it is not the victorious and illusory cry of the blinded artist: 'I have said everything', but the death of the creator which closes his experience and the book of his genius.

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The Authentic Swing: Notes From the Writing of a First Novel

The Authentic Swing: Notes From the Writing of a First Novel by Steven Pressfield

My rating: 3 of 5 stars

In this work, what might be called a pamphlet, Steven Pressfield tells the story of how he wrote The Legend of Bagger Vance: A Novel of Golf and the Game of Life. The work is interesting on a number of levels. First, it explains, in some detail, how Pressfield conceived of Bagger Vance and recreated the Hindu scriptural epic, Bhagavad-Gita. The protagonist, Rannulph Junuh, is also based on a character in the Hindu text, Arjuna (recreated as R. Junuh). Second, the work tells the story of Pressfield's love of golf, and his idea about "the authentic swing", something "remembered" rather than learnt, and recalling Saint-Exupéry (de) Antoine:

Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away.

This process of stripping oneself away to reveal the true self recalls James Allen and Kempis Thomas, but Pressfield presents this in an accessible form. Third, the work provides guidance for writers, specifically of fiction novels, but the process can apply equally to any style of writing. While the work is short, and there are entire pages devoted to only one short paragraph (making the book thicker than it need be), there is much below the surface of the iceberg that can be easily missed if this is the only work of Pressfield's one has read. It pays to have read Aristotle and the other aforementioned authors, not because one needs to to understand Pressfield, but because Pressfield brings it all together like a folk song. Read James Allen and then Kempis Thomas and one will see the connection. It is not the same, not just copied, but enlivened. That is what makes this pamphlet, and, indeed, all of Pressfield's shorter works, worthwhile.

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