Living standards have soared during the twentieth century, and economists expect them to continue rising in the decades ahead. Does that mean that we humans can look forward to increasing happiness? 
Not necessarily, warns Richard A. Easterlin, an economist at the University of Southern California, in his new book, Growth Triumphant: The Twenty-first Century in Historical Perspective. Easterlin concedes that richer people are more likely to report themselves as being happy than poorer people are. But steady improvements in the American economy have not been accompanied by steady increases in people's self-assessments of their own happiness. "There has been not improvement in average happiness in the United States over almost a half century----a period in which real GDP per capita more than doubled," Easterlin reports.
The explanation for this paradox may be that people become less satisfied over time with a given level of income. In Easterlin's word: "As incomes rise, the aspiration level does too, and the effect of this increase in aspirations is to vitiate the expected growth in happiness due to higher income." 
Money can buy happiness, Easterlin seems to be saying, but only if one's amounts get bigger and other people aren't getting more. His analysis helps to explain sociologist Lee Rainwater's finding that Americans' perception of the income "necessary to get along" rose between 1950 and 1986 in the same proportion as actual per capita income. We feel rich if we have more than our neighbors, poor if we have less, and feeling relatively well off is equated with being happy.


 
