As they crunched the numbers, George and Tirril had discovered people living in poverty were more likely to become depressed--but the data showed it was too crude to say the poverty caused the depression. No: something more subtle was happening. People in poverty were more likely to become depressed because on average they faced more long-term stress, and because more negative life events happened to them, and because they had fewer stabilizers. But the underlying lessons were true for everyone, rich, middle-class, or poor. We all lose some hope when we're subjected to severe stress, or when something horrible happens to us, but if the stress or the bad events are sustained over a long period, what you get is "the generalization of hopelessness," Tirril told me. It spreads over your whole life,15 like an oil slick, and you begin to want to give up.