Put simply, “being single increases the social connections of both women and men,” Sarkisian and Gerstel wrote in their paper.

Fostering friendship is key to aging well and boosting happiness, as several recent studies have suggested. One of them, published in 2008 in the British Medical Journal, found that people who had regular contact with 10 or more others were significantly happier than those who did not; the same study also found that people with fewer friends were less happy overall.

Friends who are not your family may be especially important.

For a pair of studies involving nearly 280,000 people, assistant professor of psychology William Chopik found that friendships become increasingly important as we age. In older people, friendships were a stronger predictor of both health and happiness than relationships with family members were.