The Dunning–Kruger Effect: Incompetent People Cannot Judge Competence — Low-ability individuals suffer from illusory superiority, mistakenly assessing their ability as much higher than it really is • High-ability individuals may underestimate their relative competence and may erroneously assume that tasks which are easy for them are also easy for others

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] (source)