From “Unskilled and Unaware of It“:
It seems that the reason for this phenomenon is obvious: The more incompetent someone is in a particular area, the less qualified that person is to assess anyone’s skill in that space, including their own. When one fails to recognize that he or she has performed poorly, the individual is left assuming that they have performed well. As a result, the incompetent will tend to grossly overestimate their skills and abilities. A few years ago, two men from the Department of Psychology at Cornell University made an effort to determine just how profoundly one misoverestimates one’s own skills in relation to one’s actual abilities. They made four predictions, and executed four studies.
Justin Kruger and David Dunning made the following predictions before beginning their investigation:
- Incompetent individuals, compared with their more competent peers, will dramatically overestimate their ability and performance relative to objective criteria.
- Incompetent individuals will suffer from deficient metacognitive skills, in that they will be less able than their more competent peers to recognize competence when they see itÃ¢â‚¬â€œbe it their own or anyone else’s.
- Incompetent individuals will be less able than their more competent peers to gain insight into their true level of performance by means of social comparison information. In particular, because of their difficulty recognizing competence in others, incompetent individuals will be unable to use information about the choices and performances of others to form more accurate impressions of their own ability.
- The incompetent can gain insight about their shortcomings, but this comes (paradoxically) by making them more competent, thus providing them the metacognitive skills necessary to be able to realize that they have performed poorly.
… In short, the study showed that the researchers’ predictions were spot-on. …
Also interestingly, the top performers tended to underestimate their own performance compared to their peers. The researchers found that those participants fell prey to the false-consensus effect, a phenomenon where one assumes that one’s peers are performing at least as well as oneself when given no evidence to the contrary.