Some 300,000 years ago, Homo sapiens split off from a long line of human-ish primates to become the first fully human species, with abilities and ingenuity unrivaled in Earth’s history. But back then, in terms of behavior and intelligence, those early humans wouldn’t have seemed so different from the other hominins they shared the landscape with — Neanderthals, Denisovans, Homo erectus and so on.

Now picture one of these ancient people beside a 21st-century counterpart, and consider how wide the gap has grown. The average person today zips from place to place in a personal metal shell that would put any cheetah to shame. They seek beauty in paintings, novels and other depictions of worlds that don’t even exist. They are embedded in socio-political networks vastly larger than the entire population of our prehistoric ancestors.

And yet! Genetically (more or less), we are them. We, with our spaceships and particle colliders, our operas and crème brûlées, our megacities and globe-spanning systems of cooperation, are made of the same essential stuff as those club-wielding nomads cooking mastodon steaks on a spit.

So, how did we get from there to here?

What Is an Ancient Human?

An ancient human is identified not by a single moment in evolution, as this process is too gradual to pinpoint when exactly we became “human.” We all share a single genetic ancestor, certainly, but that doesn’t mean there was any significant difference between them and their contemporaries; they just won the reproductive lottery.

When Did Modern Humans First Appear?

Based on fossil and DNA evidence, people that looked like us (anatomically modern) appeared in Africa about 300,000 years ago. But the archaeological record of tools and artifacts suggests they only started to act like us (behaviorally modern) 50,000 to 60,000 years ago, after thousands of generations of stasis.

This abrupt shift is sometimes called the “great leap forward” (not to be confused with Mao Zedong’s disastrous economic campaign of the same name). Experts disagree on how to explain the lag between anatomic and behavioral modernity, but for whatever reason, it seems that humans only reached an intellectual apex long after they’d come to resemble us in most other ways.

Read More: What Did Ancient Humans Look Like?

Ancient Humans vs. Modern Humans Behavior

If we compare ourselves with pre-leap humans, then, we find vast differences. Take the development of the concept of symbolism, for example: The use of objects, images, and signs to represent ideas, is a huge part of what makes us, us. It’s the key that unlocked language, along with cultural, religious, and technological innovation. That’s why archaeologists are always on the lookout for evidence of “symbolically mediated behavior,” like ritual burials, bone flutes, and cave paintings.

Problem Solving and Long-Range Planning

Another staple of modern behavior is a knack for problem-solving and long-range planning. In the archaeological record this shows up as a sudden surge, beginning roughly 60,000 years ago, in the production of advanced artifacts like fish hooks, bows, and sewing needles. Around the same time, our species was rapidly colonizing the planet, including voyages to Australia and other Pacific islands that demanded maritime expertise.

What drove this unprecedented, world-girdling success? “It was not their technology alone,” as cognitive archaeologists Frederick L. Coolidge and Thomas Wynn write in The Rise of Homo Sapiens. “It was something about their minds, an ability they possessed that their cousins did not.”

Executive Function

That “something,” in their view, is executive function: A set of complex mental processes that, among other things, enable us to achieve our goals by planning ahead, focusing our attention, reasoning abstractly and exercising self-control. The neuropsychologist Muriel Lezak has called it “the heart of all socially useful, personally enhancing, constructive, and creative abilities.”

It’s doubtful our species would’ve gotten far without executive function, a feature of the brain’s evolutionarily recent frontal lobe. These capacities allowed ancient humans to refine tools, coordinate elaborate hunts, and even sail to distant, unseen lands.

Read More: How Did Humans Evolve?

The Evolution of Human Societies: From Stone Age to Modernity

But this isn’t the full story — in case you didn’t notice, there have been some major developments since behavioral modernity emerged near the end of the Stone Age. The mental landscape of our upper-paleolithic progenitors may have been similar to our own, but in many ways, they were still closer to the earliest humans than to those in the present day.

One possible explanation of what’s happened since then is that, in fact, we haven’t changed a whole lot as individuals. Evolutionary psychologist Nicholas R. Longrich notes that the great thinkers of antiquity, like Aristotle and Buddha, were clearly just as well-endowed with intellect as anyone alive now.

The Role of Global Networks in Human Evolution

What has changed are the increasingly larger and more global networks in which we live. “Much of the difference between our ancient, simple hunter-gatherer societies and modern societies,” he writes, “just reflects the fact that there are lots more of us and more connections between us.”

That’s important because innovation grows in step with population: The more people, the more likely one of them will be the genius who invents a better spearhead (or wheel, or combustion engine, or supercomputer), setting off an intricate feedback loop in which culture evolves to ever greater levels of sophistication. And a handful of special innovations, like agriculture and writing, truly turbocharged human progress, launching us far beyond the horizons of prior generations.

In other words, it’s not that our cognitive hardware has improved since the first behaviorally modern humans, just that we enjoy the benefits of thousands of years of accumulated knowledge.

 Read More: 7 Groundbreaking Ancient Civilizations That Influence Us Today

Genetic Mutation and Evolution Across Continents

So much for our brains. When it comes to physical appearance, a glance at any diverse crowd shows that evolution was hard at work as humans fanned out across the continents.

When they embarked on their long journey out of Africa, our ancestors encountered all sorts of new environments and were forced to continuously adapt. Some of the results are visible: Genetic mutations for dark skin allowed them to withstand the harmful UV radiation of sunny locales, while small noses could better warm the cold air they inhaled in northern climates.

Other adaptations were subtler, but just as influential. Lactase persistence, for example, evolved in populations with domesticated livestock, allowing them to digest milk throughout their lives rather than only during infancy. And in mountainous Tibet, people living at high altitude acquired larger lungs to make efficient use of the region’s thin air.

Read More: Human Evolution in the Modern Age

Are There Ever Evolutionary Mismatches?

Amid all the changes of the past few millennia, the monumental shifts in our world and way of life, it’s also surprising how much we’ve stayed the same. Much of our behavior is calibrated for a long-gone ancestral environment, and we’re now often confronted by evolutionary mismatches — many traits that helped our forebears have negative consequences for us today.

Take our nearly insatiable cravings for tasty food. Ancient people often dealt with food scarcity, so it made sense for them to gorge whenever the opportunity arose. In the modern context of perpetual abundance, however, this instinct has fueled an epidemic of overeating and obesity.

All of this, the good and the bad, makes up our species’ legacy — at once fluid and enduring, it shapes our lives, our civilizations and, increasingly, the world around us. Maybe, once we brought them up to speed on spaceships and crème brûlées and what not, those early humans would even see in our world something of themselves.

Read More: Finding Human Ancestors in New Places

Article Sources

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