Dunning-Kruger Effect: Overconfidence in Incompetence

1 minutes reading time
Published 16 Nov 2023
Reviewed by: Kasper Karlsson

In the realm of psychology, few concepts have garnered as much attention as the Dunning-Kruger Effect. This phenomenon, named after psychologists David Dunning and Justin Kruger, highlights a cognitive bias where people with low ability at a task overestimate their ability.

What is the Dunning-Kruger Effect?

At its core, the Dunning-Kruger Effect is an error in self-assessment. Individuals with limited knowledge or competence in a particular area tend to overestimate their own skills, often significantly. This effect isn't just about ignorance; it's about the ignorance of ignorance. People suffering from this effect are not only incompetent; they are confidently incompetent, blissfully unaware of their lack of skill.

The Research Behind the Concept

Dunning and Kruger's landmark study in 1999 involved participants performing tasks in humor, logic, and grammar. Their findings were startling: those who scored in the lowest quartiles rated their own skills much higher than they actually were. This mismatch between perceived and actual ability forms the crux of the Dunning-Kruger Effect.

The Dunning-Kruger Effect in Investing

Novice investors, often lacking deep understanding of the markets, might overestimate their ability to pick stocks or time the market, leading to risky decisions and potential financial losses. This overconfidence, fueled by a few initial successes, can blind them to the complexities and uncertainties inherent in investing. Conversely, more knowledgeable investors might underestimate their expertise, leading to overly cautious strategies that miss out on valuable opportunities.

Why Does the Dunning-Kruger Effect Happen?

Several reasons contribute to this cognitive bias. First, a lack of self-awareness prevents individuals from accurately assessing their skill levels. Second, those with limited knowledge in a domain may not even be aware of how much they do not know, leading to an inflated sense of ability.

The Other Side of the Coin

Interestingly, the Dunning-Kruger Effect also states that highly competent individuals tend to underestimate their abilities, perceiving tasks to be easier than they are and assuming that others have a similar understanding. This phenomenon is known as the "impostor syndrome."


The Dunning-Kruger Effect serves as a reminder of the importance of self-awareness and continuous learning. Recognizing our own limitations and seeking knowledge can help mitigate this cognitive bias, leading to more accurate self-assessment and better decision-making.

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