I don't know if I agree that it's an autocorrelation, but one way to explain The Dunning-Krugger Effect is by acknowledging this simple fact:

Most people think that they are an average person, but they can't be all average—there must be some people substantially below the median. Therefore, those people must overestimate their abilities.

This also applies to other aspects, such as attractiveness. Less attractive people would overestimate their attractiveness.