This is known as the Dunning-Kruger effect. The basic idea behind it has
been a well-established rule for centuries. Charles Darwin, for
instance, has stated “Ignorance more frequently begets confidence than
does knowledge”. It has been empirically proven in 1999, by
psychologists David Dunning and Justin Kruger in their report “Unskilled
and Unaware of It: How Difficulties in Recognizing One’s Own
Incompetence Lead to Inflated Self-Assessments”.
This was proven through a study in which participants take tests of
their logical reasoning skills, grammatical skills, and humor, and then
estimate their own abilities in those subjects. Those participants who
scored in the bottom quartile grossly overestimated their own abilities.
Those in the12th percentile had estimated themselves to be in the 62nd
Overall, Dunning and Kruger found that incompetent people overestimate
their own skill level, fail to recognize the skill of other people and
fail to recognize their own inadequacy. Also, as they receive training
to improve their skills, incompetent people tend become more aware of
their own inabilities.