Matt Killingworth on the Causes of Happiness

What are the big causes of happiness?  This is what Matt Killingsworth has been studying.

From his Ted talk: When are humans most happy?

To gather data on this question, Matt Killingsworth built an app, Track Your Happiness, that let people report their feelings in real time. Among the surprising results: We're often happiest when we're lost in the moment. And the flip side: The more our mind wanders, the less happy we can be.