The larger point is that our beliefs about biology – those stupid cliches about sex hormones, for instance – often overwhelm the actual effects of biology. Thanks to some evolutionary innovations (like that overhang of brain called the prefrontal cortex), we're able to suppress our aggressive feelings and turn off our anger. We can resist even the most primal urges. And yet, all it takes is a whiff of imaginary testosterone before we start behaving like selfish hominids, imitating what we assume is our "natural" state.
Jonah Lehrer, rocking as usual