The Evolution of Modern Human Intelligence as Told by DNA

There is a lot of disagreement when it comes to modern human origins. Archeology, using studies on tools, artifacts, and cave art, suggests that modern humans, with complex cultures and technologies, evolved only around 50,000 to 65,000 years ago. But studies on fossils and DNA suggest that the modern Homo sapiens actually evolved much earlier, or approximately 300,000 years ago.

Some scientists take this difference and interpret it by suggesting that the earliest Homo sapiens were not yet truly modern. But while studies about artifacts tell us about ancient cultures, studies of genes suggest that the human brain became modern before our cultures.

The Great Leap Forward

200,000 to 300,000 years after the first appearance of the Homo sapiens, tools and artifacts remained simple. They were a little better than the technology used by Neanderthals, but they were far simpler than those used by modern hunter-gatherers.

It was only about 65,000 to 50,000 years ago when more advanced technology started appearing. During this period, tools like bows and spear throwers and other complex projectile weapons appeared. There were also other tools including sewing needles, fish hooks, and ceramics. The ancient humans were also making art, such as cave paintings of horses, idols with lion heads, and goddesses made of ivory. Artifacts like a bird-bone flute suggests that they dabbled in music. Humans also arrived in Australia around 65,000 years ago, showing that they had mastered seafaring at the time.

Called the “Great Leap Forward,” this period is generally believed to be the time when the fully modern human brain evolved. However, studies on fossils and DNA suggest otherwise.

The Anatomically Modern Human

The primitive Homo sapiens first appeared in Africa around 300,000 years ago, and their brains were as large or larger than the modern human’s. The anatomically modern Homo sapiens began to appear at least 200,000 years ago. Then at least 100,000 years ago, brain shape started becoming essentially modern, with brain cases similar in size and shape to ours.

Because their bones say that ancient humans during this period were just as human as we are now, we can assume that, theoretically, they could also do what we could do, such as writing novels, making songs, and even building space telescopes.

But fossil records can be patchy and can only provide minimum dates. Studies on the human DNA profile, on the other hand, suggests an even earlier origin of the modern human. By comparing genetic differences between modern DNA and ancient African DNA, scientists estimate that the modern human ancestor started appearing around 260,000 to 350,000 years ago.

The descendants of this ancestor, which include the Aztec, Aboriginal, Bantu, Berber, Han, Inuit, Irish, Maori, and Tamil, share similar peculiar behaviors that are not present in other great ape species. These behaviors include singing and dancing, making art, and adorning our bodies with tattoos, makeup, and ornaments. Modern humans also teach and tell stories, trade, wield complex tools, form large social groups, and cooperate to wage war. We also have laws and morals, and we contemplate the meaning of life.

While the details of these behaviors vary from tribe to tribe, all living modern humans showcase these behaviors, suggesting that the capacity to have them is innate. These form the foundation of the human condition, and they are the result of a shared ancestry.

If we go with the theory of single origin, it means that humanity is inherited from peoples in southern Africa some 300,000 years ago. The opposing theory that suggests that everyone everywhere coincidentally developed modern human behaviors around 65,000 years ago is not impossible but is less likely.

Brains and Culture

While it looks like studies in archeology and biology oppose each other, it is possible that they are actually telling different facets of the human story. Studies on bones and DNA tell us about the evolution of the human brain, which evolve slowly, while studies on artifacts tell us more about ancient culture, which rapidly evolved through time.

The ancient human ancestor journeyed out of Africa to occupy more of the planet, encountering different environments with unique climates, flora and fauna, and perils. This demanded innovation. The growth of tribes also meant more heads for innovation as well as more manpower and the improved capacity to specialize. Interactions between individuals and groups also made cultures more sophisticated.

All these resulted in a rapid improvement in technology,  which accelerated cultural evolution. By expanding our numbers and making more connections, even though the modern human brain evolved slowly, the world saw so many significant changes in the past 300,000 years.

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