NEW YORK (Reuters) -- Happiness may be hereditary, according to recent studies indicating that environment has little effect on a person's average sense of well-being over the years.
According to geneticist Dr. Dean Hamer of the National Cancer Institute, Bethesda, Maryland, a study of twins conducted by two University of Minnesota psychologists -- David Lykken and Auke Tellegen -- found that a person's level of happiness over the long-term is mostly genetic.
"In fact, it's about 80% genetic," said Hamer, whose review of this research appears in the October 1 issue of Nature Medicine.
"Even though you may go back and forth, day-to-day, between being sad and happy, depending on events, if you look at people over 10 or 20 years, their average level of contentment or psychological satisfaction is more controlled by genes than by any other factor," the geneticist explained.
Hamer said these findings "are not unexpected because many aspects of our psychological makeup are inherited... the brain, after all, is wired by our genes -- set up by our genes."
What about the impact of experience on happiness -- what a person goes through in life?
"What these psychologists point out is that experiences affect our level of contentment in the short run very strongly," said Hamer. "Your girlfriend leaves you, you feel sad; you win the lottery, you feel great. But over the long run, they really don't have that much effect."
In their study of 1,380 pairs of fraternal and identical twins, the Minnesota researchers used a self-rating scale of personal well-being at 5- and 10-year intervals. The scores for identical twins (who share the same genetic makeup) were far more similar.
According to Hamer, who is known for his work on the genetics of sexual orientation and on various character traits, "our inborn makeup" confers both resistance and a tremendous resilience to events. He noted that lottery winners one year later are no happier than they were before.
"Conversely, people who've really had a devastating accident -- who've become paralyzed -- remarkably, within a year or so after their injury, they're at the same level of satisfaction as they were before," commented Hamer.
What about the mediating effects of learning, where we learn to shape or modulate our expressions of happiness?
"I think those are extremely important, especially if you want to make the most out of your own happiness set point," said Hamer. "We're not going to change the average happiness level or the set point, but we can change where we are within our own spectrum. It's very similar to the idea of body weight. That has a strong genetic component. But by diet and exercise one can approach the optimal point of one's spectrum."
"And that's very important," he added. "If you can keep yourself at the top of your own level of functioning, you'll be feeling good."
SOURCE: Nature Genetics (1996,14:125-126)
