On their way to participate in a Black Lives Matter protest in early June in Milwaukee, Wisconsin, Jodyann and her fiancée drove past table after table of people dining at outdoor cafés. Despite stay-at-home orders, Milwaukee’s streets were crowded with protesters who wanted to make their voices heard against police brutality, and with diners taking in a leisurely meal. Both were risking their health by exposing themselves to others.
“The pandemic situation alone makes you not want to be out in a space with thousands of other people,” says Jodyann, a Black woman who has participated in a handful of protests this year. For Jodyann and many other protesters, making a difference to society is worth the risk. But, with the COVID-19 pandemic still gripping the globe and tens of thousands of new cases appearing every day, the choice to march, dine out, or join other social gatherings is complicated. While denial that the disease could hit us plays a part in some of these decisions, even people who acknowledge the danger of contracting the coronavirus keep risking social interactions. An evolutionary paradox that compels us to be social may be to blame.
Millions of years ago, our primate ancestors found safety in cooperation, developing social structures that protected them from predators and increased the likelihood of survival for them and their offspring. As early primate communities became more complex, so did our ancestors’ brains, which evolved mechanisms to process interactions and reward social behaviour with positive neurochemical feedback loops.
Social interaction has been so key to the survival of our ancestors since the Pliocene Epoch millions of years ago that the human brain may be hardwired to become addicted to it. Overcoming the primal urge to socialise means going against millennia of evolutionary programming.
“We are intensely social, as all monkeys and apes are,” says Robin Dunbar, an evolutionary anthropologist at the University of Oxford. “We depend on group-level cooperation for solving the problems of everyday survival and successful reproduction. That’s the primate adaptation, above all else.”
During the pandemic, the coronavirus has capitalised on our dependence on social interactions to spread the disease. But within that same evolutionary drive lies a possible key to making social distancing easier: As primates evolved into humans, they also developed a penchant for altruism and protecting one another.
Around 52 million years ago, with large predatory dinosaurs no longer dominating the landscape, our nocturnal primate ancestors began sneaking around during the day. However, mammalian predators like the Mesonyx—a tiger-like carnivore—were on the prowl, so these solitary primates found safety in numbers and started to band together to form loose social groups.
As time went on, our early ancestors became more social, not only foraging or hunting together, but also grooming each other and sometimes communally raising young. Primates who didn’t practice these social behaviours were left out of their communities’ protection, and few lived long enough to pass on their genes. When a behaviour increases an animal’s chances of survival like this, that behaviour can become an inherited trait, and after many generations, offspring will practice that behaviour instinctively, or perish.
Social behaviours made primate communities stronger and offered protection to individual members of the group, so they were passed down to offspring and gradually became cemented in the primate genetic code. Modern humans retain many of these behaviours.
One such behaviour is grooming, which has what Dunbar calls a high time cost, given primates devote up to a few hours a day to the behaviour. The trade off is that primates put in the time to groom each other to demonstrate their investment in the group, which reinforces their bonds and social hierarchy. The closer the bond, the more benefits for individual survival. Chimpanzees, for example, are more likely to share food with their grooming partners. Evolution has reinforced these habits by making them feel pleasurable. Grooming stimulates the release of endorphins, neurochemicals that reduce pain or make us feel relaxed or lightly energised.
Modern humans have specialized nerves—called the afferent C tactile system—that respond to light, slow stroking at the specific speed that our primate ancestors used for grooming. The behaviour remains as a vestige in our small gestures, such as when mothers fiddle with their toddlers’ hair.
“Obviously, we don’t have a lot of fur left for other people to groom in the approved primate manner,” Dunbar says. “So, we’ve adapted stroking and cuddling behaviours to produce the same effect.”
As our ancestors’ brains grew, groups increased in size, and societies evolved, but the individuals in them no longer had the time required to groom everyone in their sphere. So they developed new social behaviours that also trigger endorphins, allowing them to bond with larger groups. These behaviours include laughter, singing and dancing, eating socially, and in more recent history, the rituals of religion and drinking alcohol together, according to Dunbar’s research.
The endorphins elicited by our social behaviours are chemically related to morphine, so it’s possible to become addicted to them. We enjoy laughing and eating dinner with friends because it activates these reward pathways in the brain, and that keeps us coming back for more. But the endorphin system isn’t working alone.
“Anything that kicks in the endorphin system kicks in the dopamine system,” says Dunbar of the reward pathway in the brain that plays a role in motivation, motor control, and a variety of other neurological functions. “Dopamine gives you a zing of excitement, and that becomes addictive at a certain level.” It’s possible, in other words, that some people who keep going out to socialise despite the threat of the pandemic are addicted to the psychological and neurochemical rewards they gain from social behaviour.
Another complicating factor is the basic human drive to share resources and experiences, says Michael Tomasello, an evolutionary psychologist and professor at Duke University in Durham, North Carolina. “Even young children will point to a bird in a tree to get you to look, even before they can talk,” he says. “We have a need to share our experiences.”
This desire stems from the evolutionary benefits of cooperation, collaboration, and, eventually, culture. Studies of chimpanzee foraging techniques suggest that humans’ last common ancestor with other primates foraged cooperatively, according to a 2014 paper by Tomasello. Later, humans went a step further with their willingness to share the spoils with group members who didn’t participate in an outing of foraging or hunting.
Some researchers, including Tomasello and Arizona State University primatologist Joan Silk, believe that humans are much more altruistic than our primate cousins. In human societies, we share food and divide labour even when it doesn’t immediately benefit us. We’re motivated by empathy. This behavioural shift may have been precipitated by ecological and environmental changes that made food scarcer. “It was collaborate or die,” Tomasello wrote in his paper.
However, human generosity has its limits, and we’re more likely to act altruistically toward others if we have a social or cultural connection to them, especially if we think they might reciprocate someday, according to a paper by Silk and evolutionary psychologist Bailey House.
As competition with other human groups increased, our early ancestors started selectively sharing knowledge that could protect them from predators or outsiders. They developed the ability to create joint goals, and, in working together, they became dependent on one another for survival.
“If we’re hunting antelope, and I point to a stick that would make a great spear, if we’ve done this together before, you know what I mean,” says Tomasello. “You pick it up, and we keep going.” He believes that such shared knowledge, rooted in communal experiences, is the origin of human culture.
For modern humans, forgoing these rewarding activities of social interaction and shared experiences means going against our primal urges. But it’s not impossible.
Tomasello suggests that social media, for example, is a prime outlet for our need to share. Although connecting digitally isn’t the same as engaging in person—you can’t cuddle someone online to get those grooming endorphins—we can use social media to tap into the same reward pathways that helped build our early ancestors’ social bonds. Meeting digitally in real time to gossip, joke, and share a meal over a video call will light up the same endorphin pathways as a night out with friends. But be careful of over-scheduling digital dates, since this can lead to burnout.
Overcoming the psychological addiction to a behaviour, such as breaking the habit of going out, is the real hurdle, but it’s also doable, says Dunbar. While social media can strengthen the bonds we already have, we can also use online spaces to reach beyond our small kinship and social groups by engaging in global conversations on social media platforms such as Twitter and TikTok.
Connecting to people outside our usual sphere is crucial in this time of crisis, because it will help us form bonds with people who aren’t like us, says Dunbar. When we create those bonds, we give ourselves the tools to act altruistically, because our primal brains will respond to new friends not as outsiders, but as kin. And perhaps, building that kind of empathy can help us go against our evolutionary urges, making protecting others a much easier choice.
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