Ants could help explain why human brains mysteriously shrank thousands of years ago

Ants could help explain why human brains mysteriously shrank thousands of years ago

Science Alert reports:

In the 6 million years since our ancestors first branched off from our ancient primate relatives, the volume of the human brain has nearly quadrupled.

What many people don’t realize, however, is that sometime after the last ice age, that very brain actually began to shrink.

The result is that today, our brains are slightly smaller than those of early humans living 100,000 years ago, and yet no one really knows when or why this happened.

Now, a biological anthropologist, a behavioral ecologist, and an evolutionary neurobiologist have put their heads together and offered up an intriguing new hypothesis.

It’s based on the evolutionary history of a brain a million times smaller than our own: that of the humble ant.

If you’re thinking, ‘What does an ant have in common with a human?’, you might be surprised to learn it’s quite a lot, actually.

Although ants and humans are only distantly related, we have both evolved to develop incredibly social lives, forming large, complex, kin-oriented societies. What’s more, within these societies, labor is divided among workers of different specialties, with some ant species even producing their own crops like little farmers.

When researchers analyzed models of the brain size, structure, and energy use of worker ants, they found evidence the organ had adapted to become more efficient in social groups.

Perhaps, the authors suggest, the human brain has been similarly shaped by collective intelligence, where knowledge can be shared and distributed among a colony or community. [Continue reading…]

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