Young adults who binge drink do it because their romantic partner does it, researchers say.

More than 200 unmarried couples in their 20s participated in the study. The couples had dated for an average of about two years.

Over the course of the 28-day study, researchers at Dalhousie University in Halifax, Nova Scotia, could predict one partner’s binge drinking based on the other’s binge drinking.

“Pick your friends and lovers carefully because they influence you more than you think,” said Simon Sherry, an assistant professor in the psychology department.