Lyubomirsky: So, you can kind of be envious of them - kind of like naturally thin people, they don't really work at it. They're just skinny. So, we can be envious of them, but we can also try to model ourselves.
Narrator: Lyubomirsky has found that fifty percent of our happiness is genetic, ten percent is based on life circumstances and forty percent is within our power to change. But what if you're not born with that high happiness level to begin with?
Lyubomirsky: Again, I often make the analogy with weight or fitness. If your set point for weight is higher than you'd like, it doesn't mean that you're doomed to be overweight all your life. It just means that you have to try a lot harder. Maybe everyday for the rest of your life you need to be dieting or exercising and I think it's very similar with happiness. So, you have to put more effort into it if you're not a naturally happy person.
Narrator: For Science Today, I'm Larissa Branin.