Imagine you had the ability to predict how people’s actions in their 20s or 30s would affect their lives in their 70s and 80s. You’d have a pretty good idea of how to crack the happiness code, right? Turns out, for 80 years, Harvard researchers have been doing just that in one of history’s longest studies of happiness, the Harvard Study of Adult Development. In this episode, Arthur is joined by psychiatrist Bob Waldinger, the current director of the study, to learn about the origins of the project and the enduring lessons on happiness, aging, and relationships that it has revealed.