Kruger-Dunning Effect


What is it?

The proclivity of the unskilled and untrained to believe that one is an expert in something they realistically know little about—conversely, the tendency for experts to underestimate their abilities and assume all people know exactly as much as they do. This relationship between confidence and competence is usually depicted as a parabola, where novices have high levels of confidence and low levels of competence—while near experts have low levels of confidence, but high competence.

Why is it important for behaviour change?

This has two important functions for our work in creating change. The first is a practical understanding of the populations we’ll often work with. Many of the individuals we engage with will not be experts on most given topics and may assume certain task to be easier than they are. The second is a form of meta-awareness all behavioural scientists must balance internally. Just because we have an educated understanding of behaviour does not mean that everyone will have a similar view or knowledge-base.


Example of Theory Applied

  • A majority of drivers believe they have above average driving skills.

  • The other day I was watching a movie and thought that acting couldn’t be that difficult, it’s only pretending to be somebody else after all. A friend who is an actor offered for me to visit a set and try my luck acting a single scene. I happily accepted considering this my first step toward a prolific acting career. An hour on set and I realised, acting was one of the hardest things I had ever done: the lines were impossible to remember, it was hard to be where I was supposed to at all times, my speech was shaky, it was impossible to make myself believe I was the character, and my delivery was monotone. There are clearly levels to acting ability I was unaware of before.

  • Have you ever had a person tell you they don’t believe in climate change because the evidence isn’t sufficient enough to convince them?


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), 1121–1134.

Related Concepts

Overconfidence Bias