The Evolution of Intelligence and Modern Culture

When did we, Homo Sapiens, first appear on planet Earth? Fossils and DNA suggest that humans anatomically similar to us evolved around 300,000 years ago. But strangely enough, from the finds of tools, artifacts, jewelry, cave art etc. we've learned that complex technology and cultures evolved more recently: 50,000-65,000 years ago. This discrepancy suggests that the development of our brains, as shown by skulls and genes, is out of sync with the emergence of cultural phenomena, and that our brains became modern long before our cultures did.

The “great leap”

For 200,000-300,000 years after Homo sapiens first appeared, tools and artefacts remained surprisingly simple, little better than Neanderthal technology, and simpler than those of modern hunter-gatherers such as certain indigenous Americans. Starting about 65,000 to 50,000 years ago, more advanced technology started appearing: complex projectile weapons such as bows and spear-throwers, fishhooks, ceramics, sewing needles.

People made representational art – cave paintings of horses, ivory goddesses, lion-headed idols, showing artistic flair and imagination. A bird-bone flute hints at music. Meanwhile, arrival of humans in Australia 65,000 years ago shows we’d mastered seafaring. This sudden flourishing of technology, called the “great leap forward,” appears to have been mainly a cultural revolution.

Both genetic and cultural developments are passed on from generation to generation, but the difference is that culture is a learning process in which language plays a major role. However, the development of language seems to have taken place even before the arrival of Homo Sapiens. The Neanderthals were also able to converse with each other, as is now thought, which would imply we both inherited it from our common ancestor some 500,000 or more years ago.

Bones of primitive Homo sapiens first appear 300,000 years ago in Africa, with brains as large or larger than ours. They’re followed by anatomically modern Homo sapiens at least 200,000 years ago, and brain shape became essentially modern by at least 100,000 years ago. At this point, humans had braincases similar in size and shape to ours.

Assuming the brain was as modern as the box that held it, our African ancestors theoretically could have discovered relativity, built space telescopes, written novels and love songs. Their bones say they were just as human as we are.

Because the fossil record is so patchy, fossils provide only minimum dates. Human DNA suggests even earlier origins for modernity. Comparing genetic differences between DNA in modern people and ancient Africans, it’s estimated that our ancestors lived 260,000 to 350,000 years ago. All living humans descend from those people, suggesting that we inherited the fundamental commonalities of our species, our humanity, from them.

All their descendants – Bantu, Berber, Aztec, Aboriginal, Tamil, Maori, Inuit, Irish – share certain peculiar behaviours absent in other great apes. All human cultures form long-term pair bonds between men and women to care for children. We sing and dance. We make art. We preen our hair, adorn our bodies with ornaments, tattoos and makeup.

We craft shelters. We cook our food and use complex tools. We form large, multigenerational social groups with dozens to thousands of people. We cooperate to wage war and help each other. We teach, tell stories, trade. We have morals, laws. We contemplate the stars, our place in the cosmos, life’s meaning, what follows death.

The details of our tools, fashions, families, morals and mythologies vary from tribe to tribe and culture to culture, but all living humans show these behaviors. That suggests these behaviours – or at least, the capacity for them – have a single origin and result from shared ancestry.

Just as you can upgrade your smartphone's operating system, culture can evolve even if the hardware doesn’t. Humans in ancient times lacked smartphones and spaceflight, but we know from studying philosophers such as Buddha and Aristotle that they were just as clever. Our brains didn’t change, our culture did.

Population growth

So what happened? If Pleistocene hunter-gatherers were as smart as us, why did culture remain so primitive for so long? Why did we need hundreds of millennia to invent bows, sewing needles, boats?

First, we journeyed out of Africa, occupying more of the planet. We know from fossil evidence in southern Greece and modern-day Israel that some early members of our species expanded beyond Africa around 200,000 years ago, and again between 120,000 to 90,000 years ago. Recently, human and other animal footprints embedded on an ancient lake surface in the Nefud Desert in Saudi Arabia were discovered that are around 120,000 years old.

But this has not been a smooth and gradual development. Around 70,000 years ago, humanity's global population dropped down to only a few thousand individuals. This phenomenon is known as the human genetic bottleneck. The small group of survivors, living somewhere in Southern Africa, then began to repopulate the world. This timeline seems to coincide with the cultural revolution that took place afterwards.

Again, Homo sapiens faced new environments in the Middle East, India, Indonesia, the Arctic, with unique climates, foods and dangers, including other human species like the Naendertals and Denisovans. Different environments posed new problems that demanded innovative solutions.

Population growth also meant that there were simply more humans to invent, increasing the odds of a prehistoric Elon Musk or Leonardo da Vinci. This triggered feedback cycles. As new technologies appeared and spread – better weapons, clothing, shelters – human numbers could increase further, accelerating cultural evolution again.

Since we consider ourselves superior to all other species, we find it difficult to accept that the encounter with other human species could have contributed enormously to this development. For instance, an ivory tiara made from the tusks of the now-extinct woolly mammoth and dated to between 35,000 and 50,000 years old was recently found in the Denisova Cave in the Altai mountains of Siberia.

Hallucinogens

Others point to the role of shamanism and the use of hallucinogenic drugs, such as psylocibine and DMT, among many others. One only has to delve deeper into the various cave paintings to immediately see that this could indeed be an underexposed aspect of human development. Graham Hancock is one of the most famous proponents of this idea.

Numbers drove culture, culture increased numbers, accelerating cultural evolution, on and on, ultimately pushing human populations to outstrip their ecosystems, devastating the megafauna and forcing the evolution of farming. Finally, agriculture caused an explosive population increase, culminating in civilisations of millions of people. Thus, cultural evolution kicked into hyperdrive.

Artefacts reflect culture, and cultural complexity is an emergent property. That is, it’s not just individual-level intelligence that makes cultures sophisticated, but interactions between individuals in groups, and between groups. Like networking millions of processors to make a supercomputer, we increased cultural complexity by increasing the number of people and the links between them. A process that is still in an exponential acceleration today.

Source: The Conversation