Here's another article, this time from the Journal of Personality and Social Psychology. (Saw it referenced in an article by Robert X. Cringely, and I was intrigued.)
You know the idea that people who really know a lot about something start to realize how little they really know--in a cosmic sense? Well, I would describe the idea of this article as a corollary to that idea: People who know very little about a subject think they know a lot more than they do. Or, incompetent people don't have a clue about how incompetent they really are! Or, those who talk the most, know the least!
http://www.apa.org/journals/psp/psp7761121.html