There is a correlation between that sense of well being that keeps us this side of self-destruction and our capacity to dominate or, at the more civil reaches of society, influence, others. Primatologists note that the serotonin levels of a colonial alpha vervet monkey will rise as his political fortunes do. It is a remarkable fact that serotonin washes around in the head of a vervet monkey. It is a more remarkable fact still that the tides of serotonin washing around in your own head will, in much the same way, rise or fall as occasion and social standing dictates. It says that biology doesn't always predict your circumstances. Very often circumstances predict your biology, and from the observation that low serotonin levels accompany depression follows the adaptive intuition that oppression -- or, in a pinch, a little self-righteous bullying -- will provide the most natural means for selectively inhibiting the reuptake of one's self-satisfaction.