Wiki: Dunning–Kruger effect

The Dunning–Kruger effect is a cognitive bias in which low-ability individuals suffer from illusory superiority, mistakenly assessing their ability as much higher than it really is. Dunning and Kruger attributed this bias to a metacognitive incapacity, on the part of those with low ability, to recognize their ineptitude and evaluate their competence accurately. Their research also suggests corollaries: high-ability individuals may underestimate their relative competence and may erroneously assume that tasks which are easy for them are also easy for others.[1]
Dunning and Kruger have postulated that the effect is the result of internal illusion in those of low ability, and external misperception in those of high ability: "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."[1]...

...The phenomenon was first observed in a series of experiments by David Dunning and Justin Kruger of the department of psychology at Cornell University in 1999.[1][2] The study was inspired by the case of McArthur Wheeler, a man who robbed two banks after covering his face with lemon juice in the mistaken belief that, because lemon juice is usable as invisible ink, it would prevent his face from being recorded on surveillance cameras.[3] The authors noted that earlier studies suggested that ignorance of standards of performance lies behind a great deal of incorrect self-assessment of competence....

Historical antecedents [edit source]
Although the Dunning–Kruger effect was formulated in 1999, Dunning and Kruger have noted earlier observations along similar lines by philosophers and scientists, including Confucius ("Real knowledge is to know the extent of one's ignorance"),[2] Bertrand Russell ("One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision"),[10] and Charles Darwin, whom they quoted in their original paper ("Ignorance more frequently begets confidence than does knowledge").[1]

Geraint Fuller, commenting on the paper, noted that Shakespeare expressed a similar observation in As You Like It ("The fool doth think he is wise, but the wise man knows himself to be a fool" (V.i)).[12]

https://en.wikipedia.org/wiki/Dunning–Kruger_effect