Impatient Idealist

I can't locate the source right now, but I remember reading about a study where they discovered something like the more you understand a subject, the better you are at judging your understanding of the subject (and vice versa). In other words, those people who really don't know what they are talking about don't even know that they don't know what they are talking about, and actually probably *can't* know that they don't know what they are talking about.