The Genes That Make Us Human—and How We Thwart Them

Lascaux Cave, France. (Photo by Bayes Ahmed via Flickr)

 

 

Though I often prefer other species, humans do have an extraordinary ability to use language, tell stories, make art, share symbols, show altruism, and improve our own well-being. Why?

A new study is the first to identify 267 genes that distinguish modern humans from chimpanzees and Neanderthals. Nearly all those 267 genes helped shape the behaviors that distinguish us: creativity, self-awareness, cooperativeness, and the ability to do what doctors always nag us to do, take active steps to make sure we lead a long and healthy life.

My Jesuit philosophy professors—most of whom are dead now, a sobering thought—would hardly be surprised. They called humans’ relentless self-consciousness “awareness of awareness”—which was, as best I could tell, simply a knack for chattering inside one’s head about what one was experiencing. The Jesuits hammered home the significance: Because we do not merely perceive something but perceive ourselves perceiving it, we can come to know ourselves over time, watch ourselves react to the world, gain a little control over instinct and impulse, think in the abstract, have (and keep) faith.

Swell, but I was lugging around armloads of dense textbooks, and all this awareness seemed more curse than blessing. None of us knew, at the time, that A of A (its blackboard shorthand) was what fueled the explosion of creativity that let our species survive a threatening climate shift 100,000 years ago.

It took a while to be sure. We had mapped the chimpanzee and Neanderthal genomes, but nobody knew quite how to compare them with Homo sapiens, because our genome has changed so dramatically over the past ten million years. This research team—led by Robert Cloninger, a psychiatrist and geneticist, and Igor Zwir, an AI expert, both at Washington University—took a different tack.

First, they looked at the genes that influence human personality. Cloninger had already identified almost a thousand genes that regulate the parts of our personality we inherit. They are organized into three networks of memory and learning:

The first, which regulates our emotional reactions and the way we form habits, bond with others, and resolve conflict, emerged in monkeys and apes about forty million years ago. That network of genes is almost identical in humans, Neanderthals, and chimps. (After a fight, the study points out, chimpanzees will literally kiss and make up, and one will sling an arm over the other’s shoulders. They also pass down traditions of grooming, courting, and cuisine.)

The second network, which regulates self-control—how we form and pursue goals and cooperate, tit-for-tat—emerged almost two million years ago. It was well developed in Neanderthals, but not in chimps. (Chimpanzees can use simple tools, but they do not teach each other to manufacture and improve tools; they can learn signs, but do not spontaneously acquire symbolic language.)

The third network, which allows creative self-awareness (A of A), emerged about 100,000 years ago. The Neanderthal genome shows some of this self-awareness, but nowhere near what Homo sapiens possessed. Neanderthals buried their dead, but without grave artifacts; they produced art, but it was simple and two-dimensional.

Next, Cloninger’s team identified 267 genes that are found only in modern humans (those who began to evolve from their hominid ancestors between 200,000 and 300,000 years ago). Sure enough, most of these genes were part of the self-awareness network, regulating human personality in ways that encourage creativity, innovation, autobiographical memory, long-term planning, flexibility, altruism, and physical resilience. Because of this network, the most recently evolved regions of our brain cortex become connected, linked into a unified memory system. The sense of self can now endure through space and time. We can see ourselves as individuals and as part of a larger whole.

The development of this self-awareness network, says co-author Ian Tattersall, an anthropologist from the American Museum of Natural History, could solve an old mystery, explaining “what sparked the explosive emergence of creativity in modern humans in the period just before and after their widespread dispersal from Africa.”

At the time, we were facing imminent catastrophe—climate fluctuations and scarce resources. Our tool-making had held steady for more than a million years, showing little innovation. But under pressure, we bubbled up creativity. Suddenly we were drawing pictures from the imagination, “the mind’s eye,” and using them to tell stories on cave walls. We began to daydream, to contemplate, to let our minds wander and make surprising connections. Our memories improved, and we became more resilient to stress, injury, infection, and disease—which allowed us to spread across the world. We were also better able to trust and help others, even strangers, so we formed stronger communities (and even forged alliances across distance).

Now we are facing another climate crisis, this one largely of our own making and moving far faster. Could a fourth network emerge to help us cope?

“That is what transhumanists are suggesting, in a way,” Cloninger tells me. But rather than hunt down a fourth network, devising brain implants that use scarce materials and privilege only a few, why not make full use of the third network? “We already have the capacities to deal with the challenges we face, but we are not using them. We need to live and act like ‘modern’ humans—creatively, wisely, and humanely.” Instead, we are acting more and more “like distrustful cavemen.” The pandemic’s isolation and contagion may have exacerbated our fears, he adds, but we were already facing “social inequity, excessive consumption and greed, violence, and disinformation or propaganda in segregated news outlets.” All of which limit our capacity for self-awareness.

We face private obstacles, too. The third network is designed to help us break self-destructive habits and live by transcendent values, yet many of us slam into brick walls again and again. Why? Because “when we are exposed to conditions of fear, conflict, inequity, abuse, or neglect, our self-awareness is impaired,” explains co-author Coral del Val of the University of Granada.

Individuals who struggle with self-awareness then join a society where it is not encouraged. “Our genes for creativity and community are not a guarantee,” Cloninger remarks—especially “in a society that tolerates inequity, greed, and violence, while actively promoting consumption, individualism, and consumption.” The quest for profit overwhelms our ability to form community, and biased information divides us.

You can feel the way an experience will affect your third network, he points out: “The influences that impair self-awareness all involve feelings of separateness with fear, unmet desire, self-doubt, or false vanity. Those that promote self-awareness all involve feelings of unity with love, hope, and faith.”

We are not doomed. The point of this study is not that our behavior is determined by our genes, but that our genes have allowed us to learn new ways of behaving, adjusting flexibly to new situations and acting for the greater good. Environment will always matter, the authors note: “When reared under conditions of parental warmth and tolerance”—or helped to replace those conditions later in life—humans can develop those third-network traits of creativity, altruism, and healthy longevity. Instead of feeling separate, we can reach a self-awareness that includes other people and the natural world with which we interact.

And that will let us outwit the next crisis.

 

Read more by Jeannette Cooperman here.

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