Human Childhood is Unique — Our Childlike Curiosity Is What Drives Us to Adapt and Rebound from Adversity
These days we can’t help but reflect on how we humans handle the emotional, financial and medical pressures we are facing. So understanding what makes us human is more important than ever. We are a creative, empathetic and original species, largely thanks to the evolution of our long and unique childhoods. If not for that, we would very likely be as extinct as Neanderthals.
There’s a misconception among a lot of us Homo sapiens that we and our direct ancestors are the only humans ever to have lived on earth. It turns out that the emergence of our kind isn’t that simple. The whole story of human evolution is messy, and the more we look into it, the messier it gets.
As proof, paleoanthropologists have so far discovered that more than 30 different human species that have emerged (the experts tend to debate where to draw the line between groups). Abnd plenty more are probably out there we haven’t yet discovered. These hominids arrived after our lineage split from the common ancestor we shared with chimpanzees 7 million years ago, give or take a few hundred millennia.
To make matters worse, a fair number of these species crossed paths, competed, and mated. Populations ebbed and flowed in tight little tribes, at first on the expanding savannas of Africa, later throughout Europe, Asia, and all the way to Indonesia and Australia. Just 100,000 years ago, there were several human species simultaneously sharing the planet: Neanderthals in Europe and West Asia, the mysterious Denisovan people of Siberia, the recently discovered Red Deer Cave people living in southern China, Homo floresiensis (the Hobbits of Indonesia), and other yet unknown descendants of Homo erectus who left indications that they were around (the DNA of specialized body lice, to be specific). The picture is blurry.
Just 100,000 years ago, there were several human species simultaneously sharing the planet.
In the midst of all of this, there was our kind too, Homo sapiens sapiens (the very wise ones), still living in Africa, not yet having departed the mother continent. At most, each species consisted of a few tens of thousands of people hanging on by their battered fingernails.
Somehow, out of all of these creatures, our particular brand of human emerged as the sole survivor, and then went on, with remarkable speed, to materially rearrange the world.
If there once were so many other human species wandering the planet, why are we alone still standing? Couldn’t another version or two have survived on a world as large as ours? Lions and tigers coexist; so do jaguars and cheetahs. Gorillas, orangutans, bonobos, and chimpanzees do as well (though barely). Two kinds of elephants and multiple versions of dolphins, sharks, bears, birds, and beetles — countless beetles — inhabit the planet. Yet only one kind of human? Why?
It’s complicated, but the bottom line is this: we alone are still here because, of all those other human species, only we evolved a childhood as long as ours. Between now and the past 1.5 million years, the forces of evolution inserted an extra six years between infancy and pre-adolescence — otherwise known as a childhood — into the life of our species. And that changed everything.
Why should adding a childhood change anything? Looked at logically, it shouldn’t. You would think it would only seem to lengthen the time between birth and mating, which would slow down the clamoring business of the species’ own continuance. But there was one game-changing side effect. Those six years of life between ages 1 and 7 are the time when we lay the groundwork for the unique people you and I grow up to become. Without childhood we would never have the opportunity to step away from the dictates of our genes and develop the talents, quirks, and foibles that make us all the devastatingly charming, adaptable, and distinctive individuals we are.
Childhood came into existence as the result of a peculiar evolutionary phenomenon known generally as neoteny. The term results from two Greek words, neos meaning “new” (in the sense of “juvenile”) and teinein meaning to “extend,” as in the retention of youthful traits. In the case of humans, it meant that our ancestors passed along to us a way to stretch youth farther into life.
That happened because more than a million years ago, our direct ancestors found themselves in a real evolutionary pickle. One the one hand, their brains were growing larger than those of their rain forest cousins (gorillas and chimpanzees), and on the other, they had taken to walking upright because they spent most of their time in Africa’s expanding savannas. Both features were good for increasing the likelihood of their survival, but there was a problem: Standing upright favors the evolution of narrow hips and therefore tapers the birth canal. And that made bringing larger-headed infants to full term before birth increasingly difficult.
If we were born as physically mature as, say, an infant gorilla, our mothers would be forced to carry us for 20 months! But if they did carry us that long, our larger heads would never make it through the birth canal. We would be, literally, unbearable. The solution: Our forerunners’ children began to arrive in the world sooner, essentially as fetuses, far less developed than other newborn primates.
In the nasty and brutish prehistoric world our ancestors inhabited, arriving prematurely could have been a very bad thing. But it turns out it wasn’t. To see the advantages, all you have to do is watch a two-year-old. Human children are the most voracious learners planet Earth has ever seen, and they are that way because their brains continue to rapidly develop after birth.
Neoteny, and the childhood it spawned, not only extends the time during which we grow up, it ensures that we spent it developing outside in the wide, convoluted, and unpredictable world, rather than inside the warm and protected confines of a womb. During those six critical years, our brains furiously wire and rewire themselves, capturing experience, encoding and applying it to the needs of our particular life.
Essentially our extended childhood enables our brains to better match our experience with our environment, and that makes us more successful. We learn to avoid mistakes. We become more creative. Those experiences become the foundation of the thing we call our personalities, the attributes that make you you and me me. Without them, you would be far less unique, far less quirky and original, and less, well … you. Our childhood also helps explain how chimpanzees, remarkable as they are, can have 99 percent of our DNA but nothing like the same level of diversity, complexity, or inventiveness.
Those early, extra years have also allowed us to keep finding new ways to survive a pandemic. Look how we jabber and bristle with invention and pool together waves of fresh ideas to handle one of the most remarkable series of events and world has faced. It’s what has helped us to create and re-create that elaborate, rambling edifice we call human civilization. In fact, how we have responded to the Corona Virus is only one example of how quickly we adapt. Without all of this variety, without all of these interlocked notions and accomplishments, the world, for better or worse, would not be as it is, brimming with a species of self-aware, conflicted apes, ingenious enough to create symphonies, construct the Internet and rise up to survive a pandemic. Put another way, if not for our childhoods, we would not be the last apes standing.
Can we remain that way? I hope so. I’m counting on the child in us, the part that loves to meander and play, go down blind alleys, reach out, invent, create, sympathize and empathize.
Otherwise, would there be any sense in continuing to stand?
Chip Walter is a National Geographic Explorer, screenwriter, documentary filmmaker and former CNN bureau chief. His most recent book is Immortality, Inc. — Renegade Science, Silicon Valley Billions and the Quest to Live Forever. This article was based on Chip’s book Last Ape Standing — The Seven Million Year Story of How and Why We Survived. It is an updated version of an article originally published in Slate.com.