The study involved 501 master’s students (348 men, 153 women) at the University of Chicago. The students played a risk-taking game and gave saliva samples to measure their hormone levels before and after the game. They were also asked about their willingness to take risks, their relationship status, the number of sexual partners they’ve had, and their overall health. A portion of them (201 students) was also asked to describe themselves as a night owl, a morning person, or neither.
Sad news for insomniacs and late-night Netflix watchers: About 38 percent of night owl men and 37 percent of night owl women were single, while only 24 percent of early bird men and 20 percent of early bird women were single. And surprisingly, sleep patterns turned out to be a much stronger predictor of relationship status than risk-taking behavior or hormones.