Friends with Benefits: The latest research

Close relationships with family and friends, we know, are important for our health and well-being. But what about the people who make up our broader social networks: the parents at school drop-off, the neighbor down the street or that colleague in another department who always makes you laugh?

While research on the benefits of social connections has generally focused on the importance of "strong ties," or the intimate relationships we have with family and close friends, a growing body of research is shedding light on the hidden benefits of casual acquaintances, too. Surprisingly, these "weak ties" (that funny colleague, for example) can serve important functions such as boosting physical and psychological health and buffering against stress and loneliness, researchers have found.

Weak ties can be online acquaintances such as Facebook friends. They may also include someone you see frequently but don't know well - a gym buddy, a member of your church or synagogue, or someone you see at a regular volunteer activity.

"While most people can only keep up a few strong ties because of the time and investment they require, weak ties can number in the hundreds," says Karen Fingerman, a professor of human development and family sciences at University of Texas at Austin, who has been studying the impact of such "peripheral" ties for the past 20 years.

Decades of research suggest that having a diverse network of strong and weak ties is physically and psychologically protective. Maintaining various social roles, such as being a spouse, best friend, colleague and, say, a member of a cycling club and the PTA, is associated with better cognitive functioning, better emotional and physical health, and a decreased risk of mortality in later life.

People with high levels of what psychologists call social integration - those who participate in a broad range of relationships that consist of both intimate and weak ties - tend to be healthier and happier. Fingerman says that we don't know why wide networks have so many benefits, but a variety of reasons have been proposed: They help buffer against stress, keep us calmer and encourage positive health behaviors. At certain stages of life, they also can provide novel information that might land us a job or get us to the doctor faster.

New research highlights one way that diverse networks may influence our physical health. In a study published recently in the journal Health Psychology, researchers analyzed data from more than 4,000 people, ages 52 to 94.

The researchers wanted to see whether high levels of social integration were associated, over time, with less age-related loss of lung function, an important indicator of health and longevity. (Reduced lung function predicts mortality and disease outcomes, such as cardiovascular disease, asthma and other lung disorders.)

Participants' lung function was assessed at the start of the study and again four years later. The researchers also asked participants to report their various social roles, which required a minimum of at least one interaction a month and were limited to eight roles total. After controlling for age, education, sex, weight and height, the researchers found that the more social roles people engaged in, the better their lung function four years later.

"We found that social integration has a graded effect, so that every additional social role protects you that much more," says co-author Sheldon Cohen, a professor of psychology and the director of the Laboratory for the Study of Stress, Immunity, and Disease at Carnegie Mellon University. "Surprisingly, our data also found that low-intimacy roles, like being a volunteer or a club member, were as equally effective in protecting lung function as high-intimacy ones, like having a spouse or being a parent, which highlights the big impact a wide social network can make on your health," he says.

Cohen explains that belonging to all of these networks often motivates people to stay healthy so they can fulfill responsibilities to the people in their lives. And people in a wide network tend to encourage each other to engage in healthy behaviors.

"For these reasons, highly integrated people tend to smoke less, exercise more and have more positive emotions than negative ones," says Cohen.

As for psychological health, superficial relationships can't take the place of intimate ones, but research shows that weak ties can contribute meaningfully to well-being - if we take the time to engage with them, says Gillian Sandstrom, an assistant professor of psychology at Britain's University of Essex, who has conducted a dozen studies on weak ties.

In a two-part study published in 2014, Sandstrom recruited 58 first-year undergraduate students and 53 members of the wider community (older than 25) to test whether people would experience greater well-being and happiness on days when they interacted with more weak ties than usual.

Participants were given mechanical clickers to track strong-tie interactions (such as with "someone you are very close to") and weak-tie interactions (such as "someone you don't know well") over six days. Researchers also assessed participants' personalities, subjective happiness and well-being, loneliness, and sense of belonging.

The researchers found that students who, on average, had more daily weak-tie interactions than others or who interacted with more weak ties than usual reported feeling happier and a greater sense of belonging. Similar results were found among the community participants: An increase in weak-tie interactions left them with a greater sense of belonging, too.

"And it wasn't just extroverts that benefited from having more conversations," Sandstrom says. "The power of these daily weak-tie interactions was apparent even when differences in extroversion were accounted for."

"Just as a diverse financial portfolio makes people less vulnerable to market fluctuations," the researchers write, "a diverse social portfolio might make people less vulnerable to fluctuations in their social network." Even minimal relationships, they explain, can play a role "in fulfilling the fundamental human need to belong."

In another small study, Sandstrom conducted a field experiment in a busy urban coffee shop. The researchers recruited 60 participants and assigned half to a "social" condition, where they were asked to make "small talk, make eye contact . . . and then have a brief conversation" with the cashier, while the other half were told to be "efficient" and "avoid any unnecessary conversation."

The researchers found that participants who had the brief discussion reported an increased sense of belonging and a boost in happiness compared with those who avoided conversations. Interacting with strangers as though they are weak ties, even for just a few moments, can open up additional sources of happiness in our day-to-day lives, says Sandstrom, "and help us to feel less alone."

When our social networks are at their most vulnerable, such as during a new stage of life, a divorce or a move, weak ties offer a psychological safety net that can help us manage stress and feelings of isolation, and even buoy us through lonely times, psychologists say.

Ten years ago, Jan Scrutton and her family moved from a rural village in England to the San Francisco Bay area. The transition was tough, she says. Even minor things, such as learning to navigate around an American supermarket, became sources of stress.

Eventually, Scrutton found a store where the employees began to recognize her: "They gradually got to know my kids, noticed if we were off to a ballgame, knew if we had guests from home, asked when my dad would be back, exclaimed when my son got taller than me, cheered for graduations and asked after my daughter in the U.K."

In the first several months after the move, she says, those trips to the supermarket offered her "a feeling of being at home, being part of a community." Scrutton adds: "Without them even knowing it, there were times they saved me."