"Extreme Wealth Is Bad for Everyone—Especially the Wealthy", review of Billionaires: Reflections on the Upper Crust by Darrell M. West:

In yet another study, the Berkeley researchers invited a cross section of the population into their lab and marched them through a series of tasks. Upon leaving the laboratory testing room the subjects passed a big jar of candy. The richer the person, the more likely he was to reach in and take candy from the jar—and ignore the big sign on the jar that said the candy was for the children who passed through the department. Maybe my favorite study done by the Berkeley team rigged a game with cash prizes in favor of one of the players, and then showed how that person, as he grows richer, becomes more likely to cheat...A team of researchers at the New York State Psychiatric Institute surveyed 43,000 Americans and found that, by some wide margin, the rich were more likely to shoplift than the poor. Another study, by a coalition of nonprofits called the Independent Sector, revealed that people with incomes below twenty-five grand give away, on average, 4.2 percent of their income, while those earning more than 150 grand a year give away only 2.7 percent. A UCLA neuroscientist named Keely Muscatell has published an interesting paper showing that wealth quiets the nerves in the brain associated with empathy: if you show rich people and poor people pictures of kids with cancer, the poor people’s brains exhibit a great deal more activity than the rich people’s. (An inability to empathize with others has just got to be a disadvantage for any rich person seeking political office, at least outside of New York City.) “As you move up the class ladder,” says Keltner, “you are more likely to violate the rules of the road, to lie, to cheat, to take candy from kids, to shoplift, and to be tightfisted in giving to others. Straightforward economic analyses have trouble making sense of this pattern of results.”...Not long ago an enterprising professor at the Harvard Business School named Mike Norton persuaded a big investment bank to let him survey the bank’s rich clients. (The poor people in the survey were millionaires.) In a forthcoming paper, Norton and his colleagues track the effects of getting money on the happiness of people who already have a lot of it: a rich person getting even richer experiences zero gain in happiness. That’s not all that surprising; it’s what Norton asked next that led to an interesting insight. He asked these rich people how happy they were at any given moment. Then he asked them how much money they would need to be even happier. “All of them said they needed two to three times more than they had to feel happier,” says Norton.