Necro bumping.
The study by Dunning and Kruger proving the Dunning-Kruger Effect showed not only a tendency for the low-competence subjects to overrate their performance, but also a tendency for the high-competence subjects to underrate theirs. It's speculated that above-average performers assume their peers match them in competence due to the basic human tendency to assume other people are like them.
I think high-competence people who are depressed or have low self-esteem are especially vulnerable to this reverse Dunning-Kruger Effect, to the point where they'll often view themselves as not just average like the high-competence subjects in the study by Dunning and Kruger, but in fact, below average. Because depressed people are generally underachievers due to the nature of depression, a high-IQ person who is depressed can easily view this as proof that his IQ is below average, since IQ is positively correlated with overall life success.
