The Dunning–Kruger effect is a cognitive bias in which unskilled people make poor decisions and reach erroneous conclusions, but their incompetence denies them the metacognitive ability to recognize their mistakes.[1] The unskilled therefore suffer from illusory superiority, rating their ability as above average, much higher than it actually is, while the highly skilled underrate their own abilities, suffering from illusory inferiority. Actual competence may weaken self-confidence, as competent individuals may falsely assume that others have an equivalent understanding. As Kruger and Dunning conclude, "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" (p. 1127).[2]
The effect is about paradoxical defects in cognitive ability, both in oneself and as one compares oneself to others.
Back when I used to manage quite a number of employees, it was invariably the worst-performing who rated themselves most highly on self-appraisals and were always shocked and defensive when others (including their co-workers and supervisors alike) didn't agree with their rosy estimations of their own abilities. The more skilled and intelligent employees were much more capable of accurate self-appraisal, if anything being too critical of themselves.
It's like my dad always said. The more you know, the more you know how much you don't know. People who don't know much seldom realize how little they know.
