Evolution of Language #1: Wallace's Problem

In A Brief History of Intelligence, Max Bennett asks:

“Is language an evolutionary invention or a cultural invention?”

He investigates.

 

In the 1800’s, a scientist named Broca identified a region of the brain (called Broca’s area) which was necessary to speak. People in whom that area was damaged could not speak anymore.

 

There was another kind of patient who could speak but the sentences made no sense whatsoever! Analysis identified damage to a part of the brain, and the condition was named Wernicke aphasia after the man who identified it.

 

Two different areas of the brain for understanding speech and for speaking. And they are wired together. Sounds like we found the reason why humans have speech, but not other species like apes. Unfortunately, that is not the case.

 

Turns out those 2 areas of the brain evolved in a common ancestor, i.e., even apes have Broca’s area and Wernicke area. So it was not the evolution of these 2 areas in the brain that led to language. Nor was the development of the larynx (voice box) the key to unlocking language. This then is the neurobiological conundrum – it didn’t emerge due to some new brain area or the larynx.

 

Another weird thing about language. Pretty much every other feature – eyes, wings etc – all evolved multiple times in nature independently. But language seems to have evolved only once, in humans. Why?

 

In addition, there are almost no degrees to language. Very tiny in a few species, huge in humans, nothing in between. How to explain it?

 

The challenge only gets worse. With other capabilities, an individual benefits if he has it regardless of whether others have it or not. Not so with language. There is no evolutionary benefit to being the only one who can speak!

“Language… is only valuable if a group of individuals are using it.”

 

This problem bothered many, including one of the fathers of evolution, Alfred Wallace. At one point, he gave up and even said that perhaps language could not be explained via evolution, that only God could be its explanation. This, not surprisingly, infuriated Darwin:

“I hope that you have not murdered too completely your own and my child (the theory of evolution).”

The concession is why the origin of language was (is?) called Wallace’s problem.

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