Cognitive Biases — Dunning–Kruger effect

The research

William Poundstone — Dunning Kruger Effect
Dunning Kruger Effect with context


Dunning and Kruger asked their 65 participants to rate how funny different jokes were. Some of the participants were exceptionally poor at determining what other people would find funny — yet these same subjects described themselves as excellent judges of humour.

Why does the Dunning-Kruger Effect happen?

Why do people overestimate themselves? Are we just too confident and overate ourselves because we don’t like to be wrong? Well, Dunning and Kruger reckon it boils down to something they call “dual burden” — that not only are we incompetent but through our incompetence our mental ability is compromised which would tell us how inept we are.

“I know one thing: I know nothing” — Charles Darwin

ignorance more frequently begets confidence than does knowledge”; William Shakespeare

he who knows best knows how little he knows”. — Thomas Jefferson

Where people have little knowledge and fail, research has shown we don’t accept that we were out of our depth but instead attribute their failures to external factors. A classic example is claiming it was luck or circumstance. By doing so we protect our self-esteem instead of identifying our weakness.

McArthur Wheeler case

While researching this cognitive bias, I came across probably one of the best examples of the Dunning-Kruger effect from 1995. Mr McArthur Wheeler had read about some peculiar properties of lemon juice, that it could be used as some sort of invisible ink.


The Dunning–Kruger effect is a really interesting cognitive bias as it is relatable. What we can take away from it is that confidence is a good thing to have but it can be detrimental unless you also have the knowledge to back it up.



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Michael Gearon

Michael Gearon

Senior Interaction Designer. Living in Cardiff, South Wales, interested in human psychology and behaviours. Writing all sorts of stories that interest me.