In June 2009, The Atlantic published a cover story on the Grant Study, one of the longest-running longitudinal studies of human development. The project, which began in 1938, has followed 268 Harvard undergraduate men for 75 years, measuring an astonishing range of psychological, anthropological, and physical traits.  It revealed some insight like alcohlism being the main cause of divorce; or intelligence, beyond a certain level didn't matter; or the 'warmer' your relationships, the better your health and happiness levels in old age.  George Valiant, director of the study, summed it up best: "The seventy-five years and twenty million dollars points to a straightforward five-word conclusion: 'Happiness is love. Full stop.'"