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 said 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.
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, aged 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.)
"We found that social integration has a graded effect, so that every additional social role protects you that much more," said 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 said.
As for psychological health, research shows that weak ties can contribute meaningfully to well-being, if we take the time to engage with them, said 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.
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.