January 28, 2018

Talking Heads

If you point at something and say to your dog, “Hey, look over there!” the dog will look at your finger. If you show your dog a picture of a steak, the dog will sniff the paper and lose interest. And if you talk to your dog, the dog will enjoy the conversation, but it won’t really understand what you’re talking about. Dogs don’t “get” symbols.

A symbol is something that means something else. Symbols take the form of words, gestures, pictures, or meaningful objects. Apes and dolphins have only a limited capacity for using symbols, and other non-human animals seem to have none at all. Something happened to our ancestors that didn’t happen to theirs.

Around ten million years ago the earth’s climate began to grow cooler and dryer, causing the dense tropical forest that covered Africa to recede, leaving expanses of grassland in its place. Without the protective safety of the trees, some primates made a go of life among the big cats and other predators on the open plains. Some of them were able to stand on their hind legs, a trait favored by natural selection because it helped them see farther and detect danger sooner. Over time hominids began to walk on two legs, freeing their hands to pick up sticks and stones to use as weapons or tools.

Natural selection began to place a hefty premium on intelligence—not just any intelligence, but the kind of communicative intelligence that makes people effective in social groups. Even back then, some individuals would have been more articulate than others. Their gestures and speech-like grunts might have been easier to understand or might have expressed a richer vocabulary of thought. They would have been better at warning of danger, communicating the location of food, and coordinating group activities in hunting and battle. They would have been better parents. They would have been more attractive and seductive to potential mates. For possibly all of these reasons, natural selection favored the genes and brains of those with the gift of gab.

There must have been moments when language suddenly became capable of doing things it had never done before. There must have been a first verb, a first sentence, a first question. It’s hard to say exactly when or how this happened. Prehistory is a tale told in stones and bones, and the first words left no traces of themselves. Most estimates place the origin of language sometime between 200,000 and 50,000 years ago—between the time of the first Homo sapiens and the advent of behaviorally modern humans.

The stones and bones suggest that for hundreds of thousands of years, advances in human cognition were slow. The skulls show a small gradual increase in brain size. But the stone tools—simple sharpened rocks of generic design—stayed more or less the same.   Then something happened. Around 100,000 years ago there was a sudden blossoming of human culture. This cognitive revolution could have been the culmination of many thousands of years of gradual evolutionary changes to the brain and larynx. It could have been that the survival pressures of the Ice Age placed an even greater premium on intelligence. It could have been some powerful new feature of grammar, such as the ability to express thoughts about thoughts. For whatever reasons, human artifacts grew more advanced. The stone blades show evidence of more sophisticated sharpening techniques. Some artifacts show clear evidence that people were thinking in terms of symbols.

The oldest surviving symbols are beads, some of which are about 80,000 years old. Prehistoric beads are typically seashells with holes drilled through them. Beads are often found in burial sites, which suggests their function was somehow symbolic. Beads “said something” about the status and social role the person wearing them, in much the same way that a modern wedding ring says something about the person wearing it.

At a rock shelter in France named Abri de Cro-Magnon and at similar sites throughout Europe, archaeologists have found artifacts of a remarkably advanced human culture from about 30,000 years ago. These Cro-Magnon humans used flaking techniques to produce sharp stone blades. They left behind blades, beads, bone tools, and burial sites—the “behavioral B’s” that anthropologists consider to be the signposts of behaviorally modern humans. Those kinds of artifacts are typically found in cultures that possess art, music, myths, and even jokes.

Sadly, there are no extant Cro-Magnon jokes. I guess you had to be there.

Next: Pointing the Finger

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