In this series, I dig a little deeper into the meaning of psychology-related terms. This week’s term is the Dunning-Kruger effect.
The Dunning-Kruger effect was first described by psychologists David Dunning and Justin Kruger. It’s a type of cognitive bias that causes people to feel confident that they have greater knowledge or competence in an area than they actually do. Dunning and Kruger’s research was partly inspired by Charles Darwin’s observation that “ignorance more frequently begets confidence than does knowledge.”
Another influence in their research was McArthur Wheeler; in 1995, he robbed two banks in broad daylight with no attempt at disguise. He was later surprised when police arrested him, as he thought that applying lemon juice to his face had made him invisible to security cameras. Despite being as dumb as a sack of potatoes, he was sufficiently confident that he thought he could get away with two bank robberies.
When does the Dunning-Kruger effect appear?
This cognitive bias comes into play when people have insufficient knowledge to recognize that there’s a whole schwack of stuff they don’t know they don’t know. Because of that basic lack of awareness, or metacognition, people may not be able to recognize the distinction between themselves and people who do actually have knowledge/capability.
The effect has been demonstrated across multiple different areas of knowledge. It’s most often seen in people who know the least. In particular, it’s mostly observed in the bottom quartile (bottom 25% of performers in a given testing group). In some cases, study participants whose scores on knowledge tests were in the bottom 10% of the participant group estimated that they’d done better than about 70% of the group. Essentially, people who completely bombed the test thought that their performance was above average.
Susceptibility to the Dunning-Kruger effect doesn’t happen across the board. In Dunning and Kruger’s tests, the top 25% of performers actually showed the opposite pattern; they were actually more likely to underestimate their relative performance. The driving factor for this appeared to be that high scorers assumed that if they’d performed well, their peers must have done well also, shifting the grading curve.
The problem with surface knowledge
Considering the diagram below, usually, when you start to learn things in any sort of depth, that brings a corresponding expansion of the area in quadrant III (what you know you don’t know). You don’t actually possess that knowledge yet, but you know it’s there.
The Dunning-Kruger effect shows up when people don’t have enough knowledge in quadrant I to develop a corresponding awareness of a lack of knowledge in quadrant III, and quadrant IV (what’s entirely unknown) isn’t even on the radar.
So, watching ER gives you some surface knowledge of medicine and medical jargon, but if you haven’t managed to pick up some awareness of what you don’t know, you may think you’re ready to start doing random medical procedures on some poor, unsuspecting victim.
A similar bias is the above average effect. Consistently, more than 50% of people in a group believe they’re above average, which just isn’t possible.
What about Trump?
A Washington Post article offered Donald Trump as a prime example of the Dunning-Kruger effect in action. I’m inclined to think the same; whether you like him or not politically, he talks big talk about things that he obviously doesn’t know anything about.
His sparring with Dr. Fauci seems like a good example of Dunning and Kruger’s finding that people experiencing this cognitive bias aren’t able to recognize the distinction between themselves and people who actually are knowledgeable/capable. It doesn’t exactly set a good example to the bottom 25% who are likely to overestimate their own knowledge.
Have you noticed any examples of the Dunning-Kruger effect in action?
- Britannica: Dunning-Kruger Effect
- Kruger, J., & Dunning, D. (1999). Unskilled and unaware of it: How difficulties in recognizing one’s own incompetence lead to inflated self-assessments. Journal of Personality and Social Psychology, 77(6), 1121.
- Fritz, A. (2019): What’s behind the confidence of the incompetent? This suddenly popular psychological phenomenon. Washington Post.
The Psychology Corner has an overview of terms covered in the What Is… series, along with a collection of scientifically validated psychological tests.
Ashley L. Peterson
BScPharm BSN MPN
Ashley is a former mental health nurse and pharmacist and the author of four books.