I have not read Benjamin Friedman’s book, but Megan McArdle has.

When earnings are growing, Friedman says, people are more tolerant of minorities, more welcoming to immigrants, more solicitous of their fellow citizens, more supportive of democratic institutions, and just plain better specimens of humanity.

…People judge how well they are doing in two ways: against how well they think other people are doing and against their own (and their family’s) recent earnings. That’s why an American postal worker might not be particularly happy with his income, even though in terms of transportation, health care, and personal comfort he has a better standard of living than Cornelius Vanderbilt and other past plutocrats. Ironically, globalization therefore has made ordinary citizens in many countries unhappier with their lot, even as it has made them objectively better off. The more information people have about higher living standards elsewhere, the less content they are with their own lifestyles.

McArdle is also Jane Galt of Asymmetrical Information.