Loneliness is bad for our health, according to a robust body of research. And isolation is known to shorten lives—but experts were not sure if the real culprit was the pain and stress of loneliness, as opposed to a lack of social connectedness. Now psychologists have untangled the two factors and discovered that even superficial contact with other people may improve our health.

Led by Andrew Steptoe of University College London, the study surveyed 6,500 people aged 52 or older about their social contacts and experiences of loneliness. After seven years, the researchers followed up to see who had died. Initially, people rated as highly lonely seemed to die at a higher rate than those with low or average scores. Yet this difference disappeared when taking into account a person's health. Greater social isolation, however, came with an increased incidence of death: 21.9 percent of people ranked as highly isolated died compared with 12.3 percent of less isolated people. After taking into account health and other demographic factors, this difference amounted to a 1.26-fold increase in mortality associated with high social isolation.

The findings, published online on March 25 in the Proceedings of the National Academy of Sciences USA, suggest that even brief social contact that does not involve a close emotional bond—such as small talk with a neighbor or a bus driver—could extend a person's life. Although the results hint that city living or group homes may be beneficial, Steptoe says they do not negate the downside of loneliness. “There's ample evidence that loneliness relates to well-being and other health outcomes besides death,” he says. “But our study suggests a broader view of beneficial social relationships. They're not simply to do with close emotional relationships.”