Dunning–Kruger effect - Wikipedia

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In the field of psychology, the Dunning–Kruger effect is a cognitive bias in which people of low ability have illusory superiority and mistakenly assess their cognitive ability as greater than it is. The cognitive bias of illusory superiority comes from the inability of low-ability people to recognize their lack of ability; without the self-awareness of metacognition, low-ability people cannot objectively evaluate their actual competence or incompetence.[1] On the other hand, people of high ability incorrectly assume that tasks that are easy for them are also easy for other people.[2]