Dunning-Kruger Effect.

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 appreciate their mistakes. 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. 

This leads to the situation in which less competent people rate their own ability higher than more competent people.

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It also explains why actual competence may weaken self-confidence. Competent individuals falsely assume that others have an equivalent understanding. "Thus, 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."

Dunning and Kruger themselves quote Charles Darwin ("Ignorance more frequently begets confidence than does knowledge") and 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.")

The effect is not specifically limited to the observation that ignorance of a topic is conducive to overconfident assertions about it, and Dunning and Kruger cite a study saying that 94% of college professors rank their work as "above average" (relative to their peers), to underscore that the highly intelligent and informed are hardly exempt. 

Rather, the effect is about paradoxical defects in perception of skill, in oneself and others, regardless of the particular skill and its intellectual demands, whether it is chess, playing golf or driving a car.

Interesting huh? 

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