Scientists Have to Watch What They Say Around Language-Savvy Apes

The many forks in the road of evolution that separate humans from their cousin primates, the great apes, have taken man on an advantageous path.

Bigger brain, greater dexterity, power of reason, ability to speak, unique form of locomotion--a vainglorious litany of perks that could make other species feel as if they had completely lost out in the game of life.

If, of course, other species could ponder the problem and feel insulted.

But can they?

Some scientists working in labs with apes raised in human environments and trained in sign language are minding their words these days, being careful of a few things spoken in earshot of their test subjects. These apes, having mastered sign language, may understand spoken English.

This is not being portrayed as some new trend in evolution, and the work, swamped in criticism, is getting its share of bruises from some quarters where scientists shake their heads in disbelief.

But even though humans have broken the communication barrier with apes, the limits may not have yet been reached.

“Our biological heritage doesn’t split that much from the apes,” said Francine Patterson, the Woodside, Calif., animal psychologist who taught sign language to the gorilla Koko.

“They can understand spoken English to a certain extent and while they can’t speak English, they can understand it, somewhat on the level of a young child. They can’t understand the technical terms, but they can understand things in their experience.”

Patterson wants to find out just how well her gorilla can distinguish between subtle word differences in an attempt to discover the extent to which humans can communicate with a lower primate.

Gorillas communicate with one another in the wild, so teaching them sign language or speaking to them in English is roughly equivalent to the animal’s learning a new language, at least theoretically.

“We’ve been testing Koko’s auditory comprehension and have found that she’s able to make quite fine discriminations between such words as ear and dear . . . or funny, money and bunny, “ Patterson said.

Koko, a 400-pound lowland gorilla, answers questions by responding in sign language. And Patterson, who has insisted for 15 years that cross-species communication between human and ape could have occurred more extensively centuries ago, said Koko’s responses match those of a 4-year-old child taking the same tests.

“Genetically, we are 99% the same as the great apes, so it’s not surprising that we’re seeing these similarities,” she said.

Animal psychologist Roger Fouts of Central Washington University in Ellensburg, Wash., said the similarity between the DNA of human and ape is so strong that some scientists now “want to lump humans, chimps and gorillas under the same genus.”

He more precisely defines the genetic similarity between humans and apes as the order of nucleotides, the individual sub-units that comprise strands of DNA.

In terms of chimp-human DNA the similarity is 99.8%. With gorillas and humans, it is 99.2%, “which means we’re more closely related to chimpanzees than they are to gorillas,” Fouts said.

“We have to be very careful about what we say in the lab,” he remarked of encounters with the 22-year-old chimpanzee Washoe, who has overheard remarks made by researchers and later inquired about them, using sign language.

Animal language is not an illusion, said Fouts, “because the thought is there.” The psychologist is a proponent of the idea that language exists independent of speech.

“Chimps can acquire their first signs at 4 months old,” he said. “Deaf children acquire their first signs at 5 months. Most children don’t learn to speak until they are about a year old because the vocal cavity is not mature enough.

“Too many people confuse speech and language. Speech is a relatively new phenomenon in the human evolutionary experience. Speech, by my best guess, occurred about 200,000 years ago.

“The reason I say 200,000 years ago is because that’s when the first tools appeared that required fine, discreet motor movements with the hands, and it’s my guess that if they were working that precisely with their hands, the tongue had begun to make more refined movements as well.”

Fouts has extended his 21-year-long experiments with Washoe to controlled tests of her ability to translate words she hears in spoken English to sign language.

“Washoe was raised as if she were a deaf child,” Fouts said. “Just how much spoken English she understands, we don’t know. But we’re very often surprised.”

Patterson also expressed surprise about some subtleties of spoken English that the gorilla Koko understood.

“I read her a poem that someone had written about her, and it had a stanza that was a little bit negative, something on the order of, ‘I used to fear you.’ I asked her, ‘What do you think of this poem?’ And she signed, ‘Bad. Koko good.’

“I just read it to her in English because I didn’t know how to sign all of the words. Actually, I thought she might have liked the poem. But she picked up on the area that seemed to be a little bit negative about gorillas.”

Patterson said Koko was insulted by the apparent slight against gorillas even though the words were spoken in the relatively abstract language of another species.

“She understands extremely well,” Patterson said. “And she has very, very definite ideas about identifying as a gorilla. If I jokingly call her a chicken or a peanut, she’ll sign: ‘No, gorilla!’ I think she has a concept of herself as a person but that person is a gorilla.”

Patterson is the first to admit that her work has been plagued by criticism, much of it from people who have never worked with gorillas and those who argue that Koko’s behavior is imitative, not communicative.

“It’s a brand new field,” she responded. “That’s why there’s all this controversy and the critics are there. They’ll always be there. Some of them are my own colleagues--that’s the way science works.”

Patterson’s latest experiments include not only her work with Koko, but studies of “untaught” sign language used by gorillas at the San Francisco Zoo, where some of Koko’s relatives communicate in their own gestural system.

Patterson said such forms of communication among primates have been largely “ignored by the scientific community” because, as she sees it, some “researchers haven’t been looking at it in the right ways.”

She hopes to learn what some of the gorilla gestures mean by translating them into English, thus tapping into some of the secret conversations of gorillas in captivity.

“In their natural habitat, and even in zoos, gorillas argue with each other and relate things to each other,” she explained. “This consists of gestures that resemble sign language as well as grunts and body posture.”

Observations of natural sign languages among primates are not new.

The late animal behaviorist Dian Fossey, who lived among mountain gorillas in central Africa, once said that she was not accepted among the gorilla residents until she learned an unusual set of complex body movements. The posturing, she found, comprised a large part of the gorilla “vocabulary,” and each movement had a specific meaning.

Chimpanzee expert Jane Goodall, who has studied the animals in their natural African habitat, has written extensively on subtleties in chimp “dialects.”

The dialects are obvious variations in gestures used to express such things as grooming and food with movements differing from one chimp colony to another. Essentially, the variations are akin to differences between Boston or deep Southern dialects in human speakers of English. The words are the same, just pronounced somewhat differently.

‘Gesture Naturally’

“Chimpanzees always gesture naturally in the wild,” Fouts said. “This isn’t unusual if you know about chimps. So it makes a great deal of sense to use a human gestural language to establish communication with them.”

Forms of language among a variety of mammals are not uncommon, and scientists have been extensively studying variations in whistles among songbirds to glean meaning from them.

Studies at USC and the University of California, Santa Barbara, show that songbird whistles occur in dialects with meaning so specific to any given species that outsiders who fly in and break into song get quickly noticed by the locals.

And at sea, the highly intelligent bottle-nose dolphin has been the subject of scientific investigation for electronic communications.

Such work bolsters the spirits of Patterson and Fouts, who lament that not enough is known about animal communication and who have found that establishing a communication link--actually conversing with animals--may take a lifetime of experimentation. Patterson has been working with Koko since 1972.

But both researchers also point out that neither primate will be taught to talk.

“Koko has tried, but she cannot produce voice sounds that are verbal,” Patterson said. “She can produce sounds that sound like kisses or another that is a raspy huffing sound and she uses them in her statements. A lot of times she’ll use a kiss sound to get your attention.”

Fouts tells of experiments in another lab several years ago when scientists tried to teach a chimpanzee to talk. He said the attempts were so difficult for the monkey that it had to contort itself in unusual positions just to produce a single sound.

“And even with all of that, the sounds didn’t really sound like human speech,” he said. The experiments were called off because they were viewed as cruel to the chimp.

Can’t Be Taught to Speak

Fouts said even though the great apes are close cousins to humans, they can never be taught to speak.

“The cerebral cortex of chimpanzees is silent,” Fouts said of the outer layer of the brain hemispheres that is more refined in humans and sets man apart from other animals. “Chimps can produce vocal huffing sounds but cannot hold their breath and let it out the way humans do to produce vocal speech.”

Anatomist and theoretician Jeffrey Laitman of the Mt. Sinai School of Medicine in New York City said there are specific reasons that humans, the animals Shakespeare called “ . . .infinite in faculty . . . the paragon of animals,” stand alone in an ability to speak.

He cites noticeable differences in skull development over millions of years of evolutionary time.

Laitman said apes, like human babies, have a flat skull base that accommodates a boomerang-shaped vocal cavity but permits drinking and breathing at the same time, something mature humans cannot do.

As the human grows and the skull elongates, the vocal cavity “descends into the neck, takes a trip downward and produces something rather fascinating,” Laitman said of human speech.

“You have to have a sophisticated brain and peripheral nervous system to produce articulate speech,” which early man and present-day apes lack, Laitman said.

“We have also gained the ability to choke to death because the air path and food pathway cross each other. But the advantage we gain is that we can modify sound better than any other animals and we have gained the capacity for a large range of sounds,” he said.

Comparison of Skulls

A comparison of skulls of early humans to those of modern man show that Australopithecus, who lived several million years ago, had a flat skull base, implying a boomerang-shaped voice box.

“We don’t have a preserved throat region left, but we get our clues (about the shape of the vocal cavity) from the shape of the skull because the top of the vocal tract is also the bottom of the skull.

“Our data suggests that if we were to reconstruct the vocal tracts in these early forms (of humans), we would probably find that they were not much more advanced than today’s living chimps,” Laitman said.

To Fouts, Laitman’s theory implies that early man used gestures and grunts to communicate in ways not much different from today’s great apes.

“We still use a lot of gesturing in visual communication. In fact, 2% of the communication between friends and family members is facial expressions, gestures, body movements or intonation and speed of speech,” he said.

But there are critics who argue that a flat skull base had nothing to do with spoken language.

“There are as many opinions on (speech acquisition) as there are people to give them,” said paleoanthropologist William Kimbel of the Institute of Human Origins in Berkeley.

“I don’t think there’s any way to tell from the skulls themselves whether their possessors spoke or not,” he said. “So the acquisition of spoken language is something that we deduce.

“When you first get evidence of stone tools with repetitive patterns so that one individual in a community doesn’t make one kind and someone else another, that implies some kind of verbal transmission of ideas, a language transmission capability.”

Fouts, however, stands by his belief that human language evolved from a gestural form to the spoken languages used today. And while it may be folly to look forward to a day of talking monkeys, he said his test results assure him that chimps have a great capacity for language and expression.

“I have observed chimpanzees alone (in the lab) more or less talking to themselves in sign,” Fouts said, a habit that persists even when they are taking special intelligence and dexterity tests--something like, “Put the circular peg in the round hole, you dummy.”