It's the narcissism, not the testosterone

[nancylebov]

http://www.newscientist.com/article.ns?id=dn9374&feedId=online-news_rss20

Overconfident people are more likely to wage war but fare worse in the ensuing battles, a new study suggests. The research on how people approach a computer war game backs up a theory that “positive illusions” may contribute to costly conflicts.

Link from yhlee.