Animals Communicate, But Don’t ‘Talk’
Dogs bark. Dolphins click. Parrots mimic human speech. Vervet monkeys can even produce three distinct alarm calls to warn neighbors about leopard, eagle and snake attacks. Clearly, many animal species use vocalizations to communicate, but is that the same thing as language?
Pagel says no. Human language is “compositional,” meaning it’s made up of discrete words that are formed into sentences. Adult humans have a vocabulary of around 20,000 words that can be assembled in nearly endless combinations of subjects, verbs and objects.
“All of a sudden, we have this huge set of permutations,” says Pagel. “We can create an infinite number of sentences, and they all have different meanings based on the individual meaning of the words.”
Although the underlying mechanisms aren’t fully understood, humans are biologically hardwired to use language, while other animals aren't. A chimp can be trained to use sign language and even seals can be taught to repeat human words, but it’s always in exchange for a reward, usually food.
"You don't have to train humans to speak for a reward,” says Pagel. “They just start babbling as babies and never stop.”
As evidence that humans are born with an innate drive and gift to communicate, researchers point to a remarkable experiment from the 1980s. The Nicaraguan government opened a school for deaf children who primarily communicated through rudimentary gestures like pointing. When the children got together, however, they immediately created their own sign language complete with syntax and grammar. It was the first time researchers had documented the birth of a language.
Did Neanderthals Have Language?
Neanderthals are the closest extinct relative of modern humans, sharing 99 percent of our DNA. Neanderthals had big brains, controlled fire and used tools, but there’s no strong evidence that Neanderthals had the capacity for language.
Neanderthals lived between 400,000 and 40,000 years ago, and they coexisted for thousands of years with Homo sapiens who migrated from Africa to Europe and Asia. Yet unlike Homo sapiens, whose ancient art, sculpture and jewelry are found in the archaeological record, Neanderthals didn't leave behind any conclusive evidence of what Pagel calls “symbolic thinking.”
“One of the defining features of language is that it’s the ultimate symbolic activity,” says Pagel. “You and I are conversing at a really sophisticated level just using sounds. That's symbolism at its highest level. And when you look for symbolic behavior in the Neanderthals, you just don't see it.”
A remarkable example of early Homo sapiens symbolic art is the Lion Man, a sculpture carved from mammoth ivory with the head of a lion and the body of a man. The Lion Man dates from 40,000 years ago and was part of a flowering of human culture that included the first musical instruments.
As for Neanderthals, researchers have argued that two cave paintings in Spain were produced by Neanderthals more than 65,000 years ago, but that claim remains controversial because some researchers have questioned the dating methods.
What Evolutionary Leap Produced Language?
What was it that enabled Homo sapiens to develop symbolic language while even close genetic relatives like Neanderthals likely never got past the grunting stage? Was it some kind of physical adaptation or purely a cognitive leap?
One theory is that prehistoric humans couldn’t use spoken language until they developed the right anatomy to produce speech. When researchers examined human remains dating back hundreds of thousands of years, they found that only humans 50,000 years old or younger had larynxes and vocal chords large enough to produce the wide range of frequencies necessary for spoken language. That might explain why Homo sapiens symbolic art only took off around 30,000 to 40,000 years ago.
Pagel and other scholars are doubtful, however, that the anatomy of the vocal tract evolved expressly for language. They point to the fact that birds and other animals can mimic human speech without human vocal chords or a larynx.
If it wasn’t an anatomical adaptation that enabled speech, then it must have been a neurological upgrade. One potential candidate is a gene called FOXP2, better known as the “speech gene.” All mammals have the FOXP2 gene, but a small mutation in the human version of FOXP2—just two amino acid replacements—is thought to contribute to the fine-motor control of the facial muscles that’s lacking in chimps.
FOXP2 is a transcription factor, meaning that it works by turning at least 100 other genes on and off. “There’s this incredibly complex network of genetic interactions in the brain,” says Pagel, “and FOXP2 is just one piece of the puzzle.”
An Intelligence Tipping Point?
Another theory is that no single gene or mutation was responsible for language, but rather that human intelligence reached a tipping point after which language naturally emerged.
“The idea is that once your general information-processing capacity gets big enough, there’s more of a need to communicate in a structured way, so eventually you get language,” says Richard Futrell, who teaches language science at the University of California, Irvine.
Once language starts to emerge, there are natural constraints that shape it. The human lifespan isn’t long enough to learn and pass on millions of unique words, for example, nor is human memory good enough to remember them. These constraints create what Futrell calls a “transmission bottleneck.”
“There's a limit to the number of words you can have in the language, and that means to express complex thoughts, you have to string the words together,” says Futrell. “That gives you structure and grammar and syntax and all the things that make language unique.”
How Language Supercharged Human Evolution
Since all modern humans have language, it’s possible that our distant Homo sapiens ancestors were speaking some kind of protolanguage as far back as 150,000 to 200,000 years ago, but we’ll never know for sure. What’s clear, however, is that language played a key role in unlocking human potential.
Pagel, an evolutionary biologist, says that language has been even more central to human evolution over the past 200,000 years than our genes. In the animal kingdom, cooperation is usually confined to close kin. Animals will often only help each other if it increases the chances of passing on their own genes.
With the advent of language, humans could expand their circles of cooperation to include larger, unrelated groups. Not only could they share information and ideas more easily, but they could use language to “police” the behavior of others.
“If you don’t cooperate, I'm going to go around our community telling everyone and you're going to be ostracized,” says Pagel. “Language becomes this conduit for exchanging information and at the same time this regulator of cooperation.”
It was this ability to cooperate and collaborate and innovate that enabled Homo sapiens to migrate out of Africa roughly 70,000 years ago and spread around the world. Humans didn’t need to acquire the same kinds of genetic adaptations as other species to survive in Arctic cold or desert heat. They had language.
“It's our culture and the exchange of ideas that enables us to move into these new environments, and make the clothing and shelters and other technologies that allow us to live there,” says Pagel.
