JIM HOLT:

The happier your mood, the more liable you are to make bigoted judgments -- like deciding that someone is guilty of a crime simply because he's a member of a minority group...

As the British psychologist Richard P. Bentall has observed, "There is consistent evidence that happy people overestimate their control over environmental events (often to the point of perceiving completely random events as subject to their will), give unrealistically positive evaluations of their own achievements, believe that others share their unrealistic opinions about themselves and show a general lack of evenhandedness when comparing themselves to others." Indeed, Bentall has proposed that happiness be classified as a psychiatric disorder.

That may be going a bit far. But the evidence he cites, along with the newfound link between "well-feeling" and prejudice, might at least shake our belief in happiness as the summum bonum. Over the last few decades, it is precisely the groups that have made the most social progress in the United States -- women and educated African-Americans -- that have reported declines in their level of happiness. On reflection, this is not surprising. As education and freedom increase, desires -- and unmet desires -- inevitably multiply; our well-feeling may decrease, even as life becomes fuller and more meaningful. In Eastern nations like China, where happiness as a goal is less highly rated, people report lower levels of life satisfaction, but they also have lower suicide rates.