The Happiness Hypothesis: Putting Ancient Wisdom to the Test of Modern Science

by Jonathan Haidt

Psychologists since Freud had shared a nearly religious devotion to the idea that personality is shaped primarily by childhood environment. This axiom was taken on faith: The evidence for it consisted almost entirely of correlations—usually small ones—between what parents did and how their children turned out, and anyone who suggested that these correlations were caused by genes was dismissed as a reductionist. But as twin studies revealed the awesome reach of genes and the relative unimportance of the family environment that siblings share,30 the ancient happiness hypothesis grew ever more plausible. Maybe there really is a set point31 fixed into every brain, like a thermostat set forever to 58 degrees Fahrenheit (for depressives) or 75 degrees (for happy people)? Maybe the only way to find happiness therefore is to change one’s own internal setting (for example, through meditation, Prozac, or cognitive therapy) instead of changing one’s environment? As psychologists wrestled with these ideas, however, and as biologists worked out the first sketch of the human genome, a more sophisticated understanding of nature and nurture began to emerge. Yes, genes explain far more about us than anyone had realized, but the genes themselves often turn out to be sensitive to environmental conditions.32 And yes, each person has a characteristic level of happiness, but it now looks as though it’s not so much a set point as a potential range or probability distribution. Whether you operate...