Tracking global happiness.

As if anyone needed reminding, life isn't fair. Or as an old blues song intones, "It's a mean old world." Yet most adults report at least a moderate sense of happiness and satisfaction in major areas of their lives, such as marriage, work, and leisure, a new analysis of international survey data finds.

Researchers need to examine how so many folks manage to cut a generous slice of happiness from life's sometimes humble pie, assert Ed Diener and Carol Diener, psychologists at the University of Illinois at Urbana-Champaign. In 37 of 43 countries for which nationally representative samples are available, average ratings of well-being and happiness fall into the moderately positive range, the researchers report in the May Psychological Science. These nations include Brazil, Egypt, Japan, South Korea, Mexico, Thailand, and the United States. The only countries in the negative range were India and the Dominican Republic.

Moderate happiness also emerges in U.S. surveys of poor, physically disabled, unemployed, and elderly individuals.

"Most people are not elated most of the time," the scientists hold. "They are just mildly happy."

Surveys elicited self-reports of the degree of satisfaction in various life domains and the extent to which daily events evoked pleasant or unpleasant emotions. Several surveys also found that participants' responses matched the assessments of family members and friends.

A positive temperament may conspire with good fortune to render some individuals happier than others, according to another study in the same journal.

Identical twins, but not fraternal twins, show marked similarity to one another in self-ratings of happiness and contentedness, regardless of their education, income, marital status, or religious commitment, argue psychologists David Lykken and Auke Tellegen of the University of Minnesota in Minneapolis. Genetically derived traits may thus play a large role in how happy people feel over time, the scientists suggest.

Periodic ups and downs in life, such as a job promotion or a bad financial investment, have largely temporary effects on an individual's well-being, in Lykken and Tellegen's view.

Their study consisted of 1,380 adult pairs of identical and fraternal twins raised together and 111 adult pairs of identical and fraternal twins raised apart. Identical twins in both groups reported similar levels of happiness, unlike their fraternal counterparts, the Minnesota investigators note.