World’s Longest Study of Health, Success, & Happiness

Harvard’s Grant & Glueck study tracked the physical and emotional well-being of 268 male graduates from Harvard, as well as 456 poor men growing up in Boston from 1939 to 2014. Multiple generations of researchers analyzed brain scans, blood samples, self-reported surveys and interactions of these men to compile their findings.

The conclusions are simple. Close relationships can make or break a person’s well-being, according to Robert Waldinger, Harvard professor of psychology and director of the center behind the study.