When did something like us first appear on the planet?
It turns out theres remarkably little agreement on this question.
Fossils and DNA suggest people looking like us, anatomically modernHomo sapiens, evolved around300,000 years ago.
Somescientistsinterpret this as suggesting the earliestHomo sapienswerent entirely modern.
Yet the different data tracks different things.
Skulls and genes tell us about brains, artifacts about culture.
Our brains probably became modern before our cultures.
[Read:Are EVs too expensive?
Abird-bone flutehints at music.
Meanwhile, the arrival of humans in Australia65,000 years agoshows wed mastered seafaring.
It’s free, every week, in your inbox.
The Venus of Brassempouy, 25,000 years old.
But fossils and DNA suggest that human intelligence became modern far earlier.
At this point, humans had braincases similar in size and shape to ours.
Their bones say they were just as human as we are.
300,000 ya skull, Morocco.
All human cultures form long-term pair bonds between men and women to care for children.
We sing and dance.
We preen our hair, adorn our bodies with ornaments, tattoos, and makeup.
We wield fire and 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, lifes meaning, what follows death.
That suggests these behaviors or at least, the capacity for them are innate.
These shared behaviors unite all people.
Theyre the human condition, what it means to be human, and they result from shared ancestry.
We inherited our humanity from peoples in southern Africa 300,000 years ago.
Bones and DNA tell us about brain evolution, our hardware.
Tools reflect brainpower, but also culture, our hardware, and software.
Our brains didnt change, our culture did.
Middle Stone Age technology.
That creates a puzzle.
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.
Many of these new lands were far more habitable than the Kalahari or the Congo.
Climates were milder, butHomo sapiensalsoleft behind African diseases and parasites.
The population drove innovation.
NASA
This triggered feedback cycles.
Finally, agriculture caused an explosive population increase, culminating in the civilisations of millions of people.
Now, cultural evolution kicked into hyperdrive.
Artifacts reflect the culture, and cultural complexity is an emergent property.
So our societies and world evolved rapidly in the past 300,000 years, while our brains evolved slowly.
We expanded our numbers toalmost 8 billion, spread across the globe, reshaped the planet.
We did it not by adapting our brains but by changing our cultures.
