Scientists at the University of Texas (Austin) have shown that the more active your brain’s frontal lobe is (the decision center) the more accurate your view of your self is.
“In healthy people, the more you activate a portion of your frontal lobes, the more accurate your view of yourself is,” says Jennifer Beer, an assistant professor of psychology at the University of Texas at Austin. “And the more you view yourself as desirable or better than your peers, the less you use those lobes.”
Don’t know if I’m reading this wrong, but it looks to me like this shows that people who have an overly (or unhealthily) positive view of themselves may have limitations in their frontal lobe, which might show a lack disposition for good decision making in general (or might just show that they have some reptilian brain based love for themselves.
A lot of business writers like Peter Senge make statements that show people who know themselves accurately make better decisions and are better leaders (I would say this is at least anecdotal). Possibly there’s some neuroscience behind that as well…