But I'm not more aggressive—a behavior change often tied to testosterone. That's not surprising to Robert Sapolsky, ., a neuroendocrinologist at Stanford University and a leading researcher on stress and behavior. "It's really not the case that testosterone 'causes' aggressive behavior," he says. "Instead, it makes the brain more sensitive to social cues that trigger aggression. And in support of that, a guy's testosterone level isn't a very good predictor of how likely he is to be aggressive."
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.     
Thank you for the great article, salt is an essential part of our composition. I’ve recently started paying more attention to ‘hidden’ salt, in things like tomato sauce, organic chicken sausage, restaurant food, etc. and reducing it has made a huge impact on how I look and feel. I was by no means a processed food and restaurant junkie, but a few simple changes made a huge difference. I think salting your food with quality salt, and eating commercially salted foods are where the difference lies and this article really brought that home for me: http:///2013/03/06/salt-autoimmune-disease-sodium-multiple-sclerosis-diabetes_n_