Hedonic adaptation helps to explain why even changes in major life circumstances–such as income, marriage, physical health and where we live–do so little to boost our overall happiness. Lyubomirsky, Sheldon and another psychologist, David A. Schkade of the University of California, San Diego, put the existing findings together into a simple pie chart showing what determines happiness. Half the pie is the genetic set point. The smallest slice is circumstances, which explain only about 10 percent of people’s differences in happiness. So what is the remaining 40 percent? Lyubomirsky started with three promising strategies: kindness, gratitude and optimism–all of which past research had linked with happiness.
Conventional wisdom suggests keeping a daily gratitude journal. But one study revealed that those who had been assigned to do that ended up less happy than those who had to count their blessings only once a week. Lyubomirsky therefore confirmed her hunch that timing is important. So is variety, it turned out: a kindness intervention found that participants told to vary their good deeds ended up happier than those forced into a kindness rut. Why does acting kind make you happier?
