Victoria Tirondola and Lam Gong first struck up a conversation last spring at the dog run in Brookdale Park in Bloomfield, N.J., when they realized that each owned a dog named Abby. Tirondola, 65, an insurance sales representative who lives in nearby Cedar Grove, has a tiny bichon-poodle mix. Gong’s Abby, older and portlier, is a terrier-beagle.

They chatted about dogs at first. Then they learned that they both cooked, so “we talked about food and restaurants,” said Gong, 67, a retiree living in Clifton.

“And how much better my cooking is than his,” said Tirondola. They were sitting on a bench, as the dogs dashed around on a warm spring afternoon, with a third member of a growing collection of regulars: Pattie Marsh, dog walker for a miniature Australian shepherd named Ollie.

“All of us live alone,” Tirondola said. “My mom just passed away in July, and we were very close. Lam lost his wife a few years ago.”

“It gives us companionship” to meet at the Bark Park, said Marsh, 55. She and Tirondola, who bonded as born-again Christians, come daily. Gong joins them once or twice a week. So does Lee Geanoules, 69, a part-time restaurant server from Clifton, who soon arrived with Charlie, a pug-and-beagle blend.

Psychologists and sociologists call these sorts of connections “weak ties” or “peripheral ties,” in contrast to close ties to family members and intimate friends. Some researchers investigating weak ties include in that category classmates, co-workers, neighbors and fellow religious congregants. Others look into interactions with near-strangers at coffee shops or on transit routes.

People who cross paths at the dog run, for instance, might recognize other regulars without knowing their names (although they probably know their dogs’ names) or anything much about them. Nevertheless, impromptu chats about pets or the weather often arise, and they’re important.

Such seemingly trivial interactions have been shown to boost people’s positive moods and reduce their odds of depressed moods.

“Weak ties matter, not just for our moods, but our health,” said Gillian Sandstrom, a psychologist at the University of Sussex in England who has researched their impact.

“If I asked who you confided in, you wouldn’t mention them,” she said. Yet the resulting sense of belonging that weak ties confer is “essential to thriving, feeling connected to other people” — even among introverts, which is how Sandstrom defines herself.

In her early studies, hand-held clickers were distributed to groups of undergraduate students and people older than 25 to track how many classmates or others they interacted with, however minimally, over several days. Those who interacted with more weak ties reported greater happiness, and a greater sense of well- being and belonging, than those with fewer interactions.

The researchers found “within-person differences,” too, showing that the effects were not a result of personalities. The same people reported being happier on days they had more interactions. Other studies found similar benefits when people smiled and undertook brief conversations with baristas at a Starbucks in Vancouver, British Columbia, or greeted university shuttle bus drivers in Ankara, Turkey.

Most of these participants were quite young, but one study, published in 2020, followed an older sample of more than 800 adults in metropolitan Detroit over 23 years.

The researchers asked subjects (average age at the start: 62) to draw three concentric circles, with “you” in the center, and to arrange people in their lives by degree of closeness. Those in the innermost circle of close ties were almost always family, said Toni Antonucci, a psychologist at the University of Michigan and senior author of the study. The weak ties in the outermost circle included friends, co-workers and neighbors.

Over time the number of weak ties more strongly predicted well-being than the number of close ties. Weak ties “provide you with a low-demand opportunity for interaction,” Antonucci said. “It’s cognitively stimulating. It’s engaging.”

The COVID-19 pandemic, striking when social scientists were already raising alarms about the health risks of loneliness and isolation for older adults, suspended many of these everyday exchanges.

Seniors often kept in touch with their families, one way or another, but where were the waiters who knew their breakfast orders, the bank tellers, crossing guards and dog walkers? “I hope it made people realize how much weak ties matter,” Sandstrom said. Although they can’t replace close ones, “we missed the novelty and the spontaneity,” she said.

At older ages, when social networks tend to shrink, people might have to work at expanding them. “Make the effort,” Antonucci advised. “You can’t create new children at 70, but you can create new weak ties.”

Ilze Earner, 67, retired last year after 25 years of teaching at Hunter College in New York’s Manhattan borough. Life in rural Claverack, N.Y., had its satisfactions and friendships, but after a few months, “I started feeling like I was missing something,” she said. She began taking herself to lunch weekly, sitting at the bar at the nearby Chatham House.

Soon the bartender had learned her name (and vice versa) and of her love of lobster rolls. Earner won a bar-top game of ice cube bocce against the highway crew who also came in for lunch. “They noticed when I disappeared because I had a knee replacement, and when I came back it was, ‘Hey, bionic woman!’” she recalled. “It’s nice.”

In Placerville, Calif., David Turoff, 72, a veterinarian, chats with his mail carrier and UPS deliveryman, and sometimes drops in on the mechanic who repairs his truck just to say hello or leave a gift of firewood. “They make me feel good,” Turoff said of such brief interactions. “I like having connections with people.”

Toby Gould’s day begins with a 7 a.m. visit to Chez Antoine, a bakery and coffee shop in Hyannis, Mass. Gould, 77, a retired minister, buys a takeout latte and speaks French, haltingly, with the Belgian proprietor, who bestows a slice of ham on Gould’s Australian shepherd, Layla. If the shop closed, “it would leave a hole in my life,” Gould said.

Weak ties, including those developed online, don’t necessarily turn into close ones and don’t have to. Close relationships, after all, can involve conflicts, demands for reciprocity and other complications.

But sometimes, weak ties do evolve.

The Brookdale Park dog owners, for instance, have become real friends. They go out to dinner together and see movies and comedy shows. In bad weather they walk in a local mall. Gong, who is handy, hung curtains for Tirondola and shellacked cabinets for Geanoules; he gave Marsh a ride home when she left her car at a garage for repairs.

A bit hesitant at first to exchange phone numbers, “we took a giant step,” Geanoules said, pausing to pat and coo at one of the Abbys. “You can change a lifetime by talking to someone for 10 minutes.”

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