"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."

Incompetent
© Helga Weber
The quote above comes from the philosopher Bertrand Russell. Psychological research has now shown he was right.

The Dunning-Kruger effect is the finding that the poorest performers are the least aware of their own incompetence. The effect has been:
"...replicated among undergraduates completing a classroom exam (Dunning, Johnson, Ehrlinger, & Kruger, 2003), medical students assessing their interviewing skills (Hodges, Regehr, & Martin, 2001) clerks evaluating their performance (Edwards, Kellner, Sistrom, & Magyari, 2003), and medical lab technicians evaluating their on-the-job expertise (Haun, Zeringue, Leach, & Foley, 2000)." (From Ehrlinger et al., 2008)
The reason seems to be that poor performers fail to learn from their mistakes.

The proposed solution is that the incompetent should be directly told they are incompetent.

Unfortunately the problem is that incompetent people have probably been getting this type of feedback for years and failed to take much notice. Despite failing exams, messing up at work and irritating other people, the incompetent still don't believe they're incompetent.

As Socrates once said:
"The only true wisdom is to know that you know nothing."
But even this can go too far. It turns out that people with real talent tend to underestimate just how good they are. The root of this bias is that clever people tend to assume other people find things as easy as they do, when actually this is their talent shining through.