There is this difference between happiness and wisdom, that he that thinks himself the happiest man really is so; but he that thinks himself the wisest is generally the greatest fool.
New research indicates that incompetent people tend not to know they are incompetent. Not only that, they also tend to be very confident that they know what they're doing -- even more confident of their own competence than people who really do know what they're doing.
The New York Times reports that Cornell University psychology professor David Dunning reached those conclusions in a study he conducted with a graduate student, and wrote about his findings in the December 1999 issue of the Journal of Personality and Social Psychology.
The researchers concluded that one reason incompetent people do not know how much they do not know, is that the cognitive skills required to be competent are also required for recognizing actual competence.
Researcher Justin Kruger told the Times that the incompetence of incompetent people "robs them of their ability to realize" they have a problem. It also makes it difficult for incompetent folks to recognize competence in others.
By the way, the researchers say they also noticed that people who can't tell a joke tend not to realize that they're not funny -- and as a result they persist in telling jokes badly.