" To draw for a moment from an entirely different corner of my life, that part of me still attached to the biological sciences, there is ample evidence that animals — rats and monkeys, for example — that are forced into a subordinate status within their social systems adapt their brain chemistry accordingly, becoming 'depressed' in humanlike ways. Their behavior is anxious and withdrawn; the level of serotonin (the neurotransmitter boosted by some antidepressants) declines in their brains. And — what is especially relevant here — they avoid fighting even in self-defense ... My guess is that the indignities imposed on so many low-wage workers — the drug tests, the constant surveillance, being 'reamed out' by managers — are part of what keeps wages low. If you're made to feel unworthy enough, you may come to think that what you're paid is what you are actually worth. "

― Barbara Ehrenreich , Nickel and Dimed: On (Not) Getting by in America