What is the Dunning-Kruger effect in simple terms?

The “Dunning-Kruger” effect is a phenomenon known in the field of psychology that refers to the tendency of individuals with low ability or knowledge in a particular area to overestimate their own competence or skill level.

This theory was developed by American psychologists, David Dunning and Justin Kruger, in 1999 paper titled “Unskilled and Unaware of It: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments.”

Why is it called “brother-in-law syndrome”?

This unofficial name has been given to the Dunning-Krugger effect because of the idea that society has of the typical brother-in-law. It suggests that a brother-in-law, or any other relative, is overly confident or outspoken about a particular topic or skill despite lacking the expertise or competence in that area.

A clear example of “brother-in-law syndrome” is when we are watching television for a while and while watching a program we doubt or complain about the competence of some public figures such as politicians, businessmen, intellectuals, talk shows or presenters.

How does the effect work?

People who lack expertise or competence in a specific domain often fail to recognise their own limitations. They may mistakenly believe they are more skilled or knowledgeable than they actually are. As a result of their limited understanding, individuals with low competence tend to overestimate their abilities. They may express high levels of confidence in their judgments or skills despite evidence to the contrary.

With increasing knowledge and experience, individuals often become more aware of their limitations. This realization tends to lead to a more accurate assessment of their abilities. Conversely, individuals with high levels of expertise may underestimate their competence because they assume that others possess similar knowledge and skills.