One reason that the ignorant also tend to be the blissfully self-assured, the researchers believe, is that the skills required for competence often are the same skills necessary to recognize competence.
The incompetent, therefore, suffer doubly, they suggested in a paper appearing in the December issue of the Journal of Personality and Social Psychology.
``Not only do they reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the ability to realize it,'' wrote Kruger, now an assistant professor at the University of Illinois, and Dunning.
This deficiency in ``self-monitoring ...

One reason that the ignorant also tend to be the blissfully self-assured, the researchers believe, is that the skills required for competence often are the same skills necessary to recognize competence.
The incompetent, therefore, suffer doubly, they suggested in a paper appearing in the December issue of the Journal of Personality and Social Psychology.
``Not only do they reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the ability to realize it,'' wrote Kruger, now an assistant professor at the University of Illinois, and Dunning.
This deficiency in ``self-monitoring skills,'' the researchers said, helps explain the tendency of the humor-impaired to persist in telling jokes that are not funny, of day traders to repeatedly jump into the market - and repeatedly lose out - and of the politically clueless to continue holding forth at dinner parties on the fine points of campaign strategy.
In a series of studies, Kruger and Dunning tested their theory of incompetence. They found that subjects who scored in the lowest quartile on tests of logic, English grammar and humor were also the most likely to ``grossly overestimate'' how well they had performed.
In all three tests, subjects' ratings of their ability were positively linked to their actual scores. But the lowest-ranked participants showed much greater distortions in their self-estimates.
Asked to evaluate their performance on the test of logical reasoning, for example, subjects who scored only in the 12th percentile guessed that they had scored in the 62nd percentile, and deemed their overall skill at logical reasoning to be at the 68th percentile.
Similarly, subjects who scored at the 10th percentile on the grammar test ranked themselves at the 67th percentile in the ability to ``identify grammatically correct standard English,'' and estimated their test scores to be at the 61st percentile.