Consider the wild tiger. It consorts with fellow tigers only to mate or, if female, to briefly raise cubs. Otherwise, the tiger roams solo. Tigers are great at social distancing.

We are not tigers. Amid a novel coronavirus pandemic, some of us have defied public health officials’ exhortations and headed to bars to be with other members of our species. More of us have stared into the weeks to come and wondered how we will cope without basketball games, book groups, worship services, yoga classes and dinners with friends.

Hermits aside, humans are social animals, even what some call “ultra-social.” For millennia, survival has depended on being part of a group. If distancing seems hard, it’s not just you: It’s human nature.

“Humans are just really intrinsically social creatures. We are the most extreme example of a species that’s decided that collaborating with others is going to be my entire strategy,” said Steve Cole, a professor of medicine, psychiatry and biobehavioral sciences at the University of California at Los Angeles School of Medicine. This has served us well, he added: “Despite the fact that we’re not that big or strong or covered by armored plates, we’ve managed to take over the world, in a literal sense.”

Primates are social, but we are distinctly so. For starters, we are especially cooperative, a trait that some researchers say stemmed from ecological changes that forced early Homo sapiens to forage together. We are among the few species that choose to share with one another. Lions may hunt and feast on prey together, “but they won’t bring any back,” to others, said Alan Fiske, a psychological anthropologist at UCLA.

And more than any other mammal, we divide labor, Fiske said.

“If you look around yourself right now, there’s probably nothing in sight that you yourself made or produced for your own use,” he said. “None of us are able to do individually all the things that we need. But by each of us doing a specialized job, then we function beautifully.”

These social skills helped our ancestors fend off predators and more efficiently gather and hunt food and raise offspring. Our emotional dependence on each other can make keeping our distance, even for the public health benefit of “flattening the curve,” feel crummy.

“Because it’s so adaptive, so tremendously beneficial for your survival and reproduction, over hundreds of thousands of years, humans have evolved to have psychological needs,” Fiske said. “Your needs tell you it’s important to relate to people.”

That’s true both of intimate interactions, such as dining together, and the group experiences canceled in recent days, Cole said — from concerts to work meetings to sporting events.

“We all think that what’s important is the performance of the athletes. But we really underplay the performance of the spectators in creating a sense of presence,” Cole said. “You’re part of the same exciting experience, and you don’t know what’s going to happen next, and we’re all in the same boat.”

So important is social connection to humans that the lack of it is terrible for our health. America already has high levels of loneliness, considered a public health hazard in itself even before coronavirus isolated us further. Scientists distinguish solitude from loneliness: Lonely people are hungry for connection but have too little. And a wide body of research has found lonely people are at higher risk for a host of illnesses, including heart disease, cancer and Alzheimer’s.

Cole has studied why, and he has found some history in our genes. Because humans are so social, viruses — like the one that causes covid-19 — love us. Viruses spread best through close personal contact, whether that’s in a colony of bats or a dorm full of freshmen. In an evolutionary arms race, that’s caused us to build up robust antiviral defenses in our immune systems. As Cole puts it, we lean on our antiviral leg.

Feeling socially isolated, though, triggers a fight-or-flight response, just as it would have in our ancestors, for whom being alone could mean being a saber-toothed tiger’s lunch. This revs up inflammation, an immune system response suited to fighting bacterial infection — a likely outcome of being wounded, Cole said. The body pivots, he said, to its antibacterial leg.

In ancient humans, this response would have been fleeting. But the stress of modern times, Cole said, leaves many people feeling “chronically insecure,” keeping the response at a simmer. So does loneliness, which some researchers characterize as an epidemic. And inflammation, it turns out, fertilizes chronic diseases while also leaving us more vulnerable to viruses.

All of this helps explain why hunkering down at home to slow the coronavirus epidemic feels so wrong, even though, researchers say, it isn’t likely to raise rates of loneliness or make us sick.

Chronic diseases such as cancer develop over decades, not the weeks or months of a national shutdown. Although studies of monkeys have found the immune response to social isolation can kick in quickly, Cole said, any reduced virus resistance that may result from this unprecedented national exercise in alone time could be offset by lower exposure to the coronavirus — and is well worth it.

“These kind of measures are not trying to make you lonely, but trying to make the virus lonely,” said Stephanie Cacioppo, an assistant professor of psychiatry at the University of Chicago’s School of Medicine who studies social relationships and loneliness.

Most who are reducing physical contact, of course, are not locking themselves into isolation chambers. They’ve got a few relatives or friends around. Technology and social media, often derided as a threat to the social fabric, should now be viewed as a lifeline.

“People are going to feel isolated and lonely unless they make an effort to reach out to each other, so what we have to do is make sure that we call people on the phone and Skype with them and send them texts and emails, especially the people who are least proficient on the Internet,” Fiske said. “You can still bring a casserole over and ring somebody’s doorbell and leave it on the stoop.”

Sidewalk chats at a safe distance are still okay, Cacioppo noted. But even people who avoid those can adopt other habits to feel connected to others. If you close your eyes and think of a loved one smiling, you’re likely to smile yourself, she said. Do it for two minutes a day, she said, and “you can really improve your well-being and happiness level.” Writing about your feelings in an email or letter to friends and family is another helpful exercise, she said.

Although we have evolved to depend on each other, we have also evolved to have rational minds that understand empty streets and shuttered schools will not last forever, Cacioppo said. In the meantime, we can focus on upsides of being shut in: More time with children, maybe, or with books, or sleeping. Less time in traffic.

“It’s a serious situation,” Cacioppo said. “But I really believe that we are in a golden era of social connection, and this is an opportunity for us to have a mental reset and remind us of what it means to be social.”

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