The happiness of individuals is an important metric for societies, but we know little about how daily life events together influence how happy we feel. To address this question, Robb Rutledge, Assistant Professor of Psychology at Yale University, has collected data both in their lab and from thousands of people around the world playing games on their smartphone app The Happiness Project. They find that happiness depends not on how well you are doing but whether you are doing better than expected. Using brain scanning, they find areas of the brain that predict future happiness and that relate to the differences between individuals in what determines happiness.