Traders: Testosterone-levels predict risk-taking, not skill
FT. I think this is the really interesting paragraph, however:
As an aside, learning, like outperformance, is incompatible with the efficient markets hypothesis, according to which the markets follow a random walk and you can no more learn to trade them than you can improve at flipping coins. Our data therefore suggest the markets are not in fact random.
Well, so much for the efficient markets hypothesis...
NOTE Via Yves.