Our species is believed to be between 200,000 and 300,000 years old and yet there’s no evidence of symbolic behavior until about 88,000 years (engraved ocher from Blombos cave, South Africa) and there’s no evidence of true art until about 40,000 years ago in Europe.

What took so long?

Was this just a slow accumulation of cultural knowledge, or as Stanford professor Richard Klein has argued, was the human brain not genetically capable of higher level creativity until around the time we left Africa?

One incredibly evil way scientists could answer the question would be to raise a bunch of modern humans from birth with no language, art, technology, clothing or modern advances of any kind.  If these humans start talking and creating symbols within a few generations, we’d know Klein was right and that there was a genetic mutation that suddenly allowed our species to acquire behavioral modernity quite rapidly.  On the other hand, if these humans take over 100,000 years to create language and art, then it will prove we’re no genetically smarter than the earliest members of our species, we’ve just had more time to create culture.

But if we are genetically smarter, how did we become that way?

Increasing brain size can’t fully explain it.  While it’s true brains grew as people entered freezing Europe and created the first art, those who stayed in the tropics would also display impressive cave art, independent of European influence.

So perhaps the explanation lies not in brain size, but in neurotransmitters.  In a recent issue of Scientific American, scholar Liane Gabora argues that humans lacked the neurotransmitters to fully exploit our huge brains until around 100,000 years ago at which time we evolved an ability to switch easily from analytical to associative forms of thinking

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