Dunning-Kruger Effect

Cognitive bias in which people assess their cognitive ability as greater than it is.

Snippet from Wikipedia: Dunning–Kruger effect

The Dunning–Kruger effect is a hypothetical cognitive bias stating that people with low ability at a task overestimate their ability.

As described by social psychologists David Dunning and Justin Kruger, the bias results from an internal illusion in people of low ability and from an external misperception in people of high ability; that is, "the miscalibration of the incompetent stems from an error about the self, whereas the miscalibration of the highly competent stems from an error about others". It is related to the cognitive bias of illusory superiority and comes from people's inability to recognize their lack of ability. Without the self-awareness of metacognition, people cannot objectively evaluate their level of competence.

The effect, or Dunning and Kruger's original explanation for the effect, has been challenged by mathematical analyses and comparisons across cultures.

Outside psychology, non-professionals often invoke the Dunning-Kruger effect to insult people. Mark Murphy calls this abuse of the theory a form of "weaponized psychology".