Surprised that your life circumstances have such little influence on your happiness? Researchers have found that people eventually return to their genetically-determined happiness set points after big changes in life, as seen in lottery winners and newlyweds.
Four years ago, Caroline Johnson volunteered for the ABC show "Extreme Makeover," and received everything from a new nose to new teeth and the requisite breast implants. Did these physical improvements make her happier?
"I think about a year it made a difference," she said. "People are seeing you for the first time and they compliment you all the time. And then once it wears off, it's just normal life again."
"It's a phenomenon called hedonic adaptation," explained Lyubomirsky. "We tend to adapt to any kind of positive change …once you make $100,000, now you sort of change your goals. Now your goal is to make even more."
Identical twins reared in the same household who do not share the same levels of happiness can also provide clues about what it is in our lives that make us happy -- the 40 percent of happiness within our control. Johnson is the perfect test case for the 40 percent theory, because she herself has an identical twin, Cat Bunnell.
After Lyubomirsky gave the sisters a battery of questionnaires she "was stunned [by] how different their scores were. Caroline got a 5.5 out of 7 … pretty happy," she said. "Cat scored a 3.25 … below the midpoint on happiness."
"They have the same DNA," explained Lyubomirsky, "and so to try to explain why one is happier than the other you have to kind of look at other factors."
One reason for the happiness difference between the twins is their outlook on life. Johnson is a self-employed dog groomer whose business hit a rough patch recently, yet she remains upbeat and committed to success. "I'm very optimistic … I know where I want to be," she said. "By next summer I have definite goals that I expect to meet."
Her sister has a very different outlook on life. Regarding her future, Bunnell said, "I don't feel like I'm progressing as much as I want to in my job or just the financial situation … It just feels like it just weighs on me too much and I just feel like I'm not going to get out of it."
"We really see major differences between the level of optimism that they have," said Lyubomirsky. "(We see) Caroline being more optimistic, Cat kind of ruminating and dwelling more on sort of bad things."
Perhaps another reason why Johnson is happier than her sister is her ability to nurture relationships. Johnson is married with three children, while Bunnell is a divorced single mom, struggling with the dating scene at age 37.
"I don't have somebody that can just hold me because I'm having a hard time," said Bunnell.
Regarding her prospects for finding another husband, she said, "I feel like I'm really giving up on all that."
Besides the optimism, commitment to goals, and ability to nurture relationships that might make Johnson happier than her twin, there are many more ways to affect the 40 percent of happiness in your control.
"The happiness activities are not going to surprise anyone," Lyubomirsky said. "I mean, they're things like gratitude, forgiveness, relationships, savoring the present moment, meditation. I try to sort of determine to what extent those things are supported by research."