SCOTT SIMON, Host:
This is WEEKEND EDITION from NPR News. I'm Scott Simon.
Somewhere in Iowa, two bonobo chimpanzees named Kanzi and Panbanisha will be listening to this next story, and they'll understand a lot of it. Good morning. These bonobos know thousands of words. They use sentences. Their linguistic skill is so remarkable it's changing scientists' thinking about the nature of human language.
In the first of a series of language, NPR's Science Correspondent Jon Hamilton and producer Anna Vigran went to Iowa to meet Kanzi and Panbanisha and the scientists who work with them.
JON HAMILTON: We're in a waiting room at the Great Ape Trust near Des Moines. We've got an appointment to see Kanzi. He's the world's most famous bonobo and a bit of a showoff. But Kanzi's little sister, Panbanisha, has other plans.
(SOUNDBITE OF CHIMPANZEES)
HAMILTON: She's demanding to see the visitors from the radio. And in the bonobo world, females make the rules.
(SOUNDBITE OF CHIMPANZEES)
HAMILTON: Dr. Sue Savage-Rumbaugh is the undisputed authority figure here, even though she's not much taller than a bonobo. Today she's wearing a wireless microphone so we can hear what's going on even when she's several rooms away.
SUE SAVAGE: Panbanisha usually is very reticent to meet visitors and she wants Kanzi to do all the talking, but she's dying to meet you. She's pleading. She rolled over on her back and threw a temper tantrum. I haven't seen her do that in years.
HAMILTON: It worked. Panbanisha gets her way.
SAVAGE: You want to talk to the visitors, huh?
HAMILTON: That's right, talk. Panbanisha has the language skill of at least a preschooler. She understands spoken words, but she can't make human sounds herself. So she's learned to touch symbols on a computer screen or on a laminated sheet the scientists call her keyboard.
We meet in a small room divided by a large window. Panbanisha's on one side, we're on the other with Sue Savage-Rumbaugh, or Dr. Sue as she's called her.
SAVAGE: This is Panbanisha. She wants to see you.
HAMILTON: Panbanisha peers through the glass. She had large brown eyes, small ears, a pink mouth and black hair parted down the middle. And she's less than four feet tall.
SAVAGE: Oh, she's bringing her ladder over so she can see you better. What do you want to say to her?
HAMILTON: I suggest we go for a walk.
SAVAGE: She's going to say something. See her looking at her keyboard? She wants to put her (unintelligible).
HAMILTON: As we talk, Panbanisha makes sure we make a clear view of her finger as she points to each symbol. Every symbol corresponds to a word. A circle perched on a triangle means lemonade. After some negotiating, we agree on a car ride instead of a walk. Panbanisha celebrates by playing her drum.
SAVAGE: We're going to go in the car! We're going to go in the car!
HAMILTON: Panbanisha gets her car ride, but we don't go along. There's too much to do: talk to the scientists, visit the orangutans, who also live here at the Great Ape Trust, and of course, meet the famous Kanzi.
We catch up with Kanzi at the bonobo home. It's nice - heated floors, natural light, indoor climbing towers. We're sitting on the floor. Kanzi's a few feet away with Dr. Sue. He's snacking on peanuts and drinking water from the hose. He's also trying to figure out what's in Sue's pocket.
SAVAGE: That's my microphone. I got all this stuff in my pocket. It's not to take out right now.
HAMILTON: Then he sees the present we brought him and grabs his laminated keyboard.
SAVAGE: Carry that ball here. Uh-huh. I understand what you're saying. See, they're nodding yes.
HAMILTON: Scientists have spent centuries trying to figure out if there's something special about humans that allows us to use language. They've also wondered just how much language other animals could learn. That's led to a series of experiments with apes.
The early results were generally disappointing. And then Sue Savage-Rumbaugh met Kanzi.
Dr. Sue tells the story from a small office next to the train track. No heated floors or climbing towers here. The humans work out of a modest double wide.
Kanzi was born in Georgia 26 years ago. At the time, Dr. Sue was trying to teach words and symbols to Kanzi's adopted mother, Matata. Kanzi was in the classroom too, but Dr. Sue wasn't trying to teach him anything.
SAVAGE: Kanzi would just be around. He would often be on my head or jumping down from the top of the keyboard into my lap. If we ask Matata to sort objects, he would jump in the middle of them and mess them all up. So he was just a normal kid.
HAMILTON: Sue thought Kanzi recognized a few words, but it wasn't clear how much Kanzi knew until he lost his mother. Matata was taken away for breeding. Kanzi was just two-and-a-half then. At first, he thought his mother was hiding. When he couldn't find her, little Kanzi was bereft. So he turned to his best friend, Dr. Sue. He desperately wanted her help, and he began using her language to get it.
SAVAGE: Kanzi began using the keyboard that day. He used the keyboard, I think, 320 times the first day that he was separated from Matata.
HAMILTON: He asked her for food. He asked for affection. He asked for help finding his mom. At the time, Sue Savage-Rumbaugh was too worried about Kanzi to fully appreciate what he was doing. But later she had an epiphany. Whatever language was, it was more than words and sentences. It must have deeper roots in social connections and a shared understanding of the world.
That's a given these days at the Great Ape Trust. One of the young bonobos has even made trips to Starbucks with his human friends.
But in the 1980s, Dr. Sue's idea seemed radical. For one thing, it challenged the view of some prominent linguists, including Noam Chomsky. They believed the key to language development was an innate understanding of grammar and that it was unique to humans.
Dr. Sue made a decision: no more trying to teach words and sentences to apes. She would give Kanzi a reason to talk and something to talk about.
SAVAGE: What I had to do was come up with an environment, a world, that would foster the acquisition of these lexical symbols in Kanzi and a greater understanding of spoken human language.
HAMILTON: She created a world where Kanzi would learn the way human babies do. He and his human friends would eat together and play together. And because bonobos love to travel, they would hike together around the 55 acres they called home.
SAVAGE: Whenever we talked about a travel destination, we had Kanzi's immediate attention. And if we showed him a photo, he wanted to take that photo and he wanted to hold it. He wanted to ride on our shoulders and hold the photo and look at it all the way to the place.
HAMILTON: Before long, Kanzi was doing many of the things humans do with language. He was talking about places and objects that weren't in sight. He was referring to the past and the future. And he was understanding brand new sentences made up of familiar words, like Coke. Kanzi's a big fan of cola.
Sue tells this story. She and Kanzi used to picnic beside a somewhat polluted river. Every now and then, an empty Coke can would float by. Sue told Kanzi that people had thrown the cans in the river. At first, she wasn't sure he understood.
SAVAGE: I remember the first day I ever asked him, Kanzi, could you throw your Coke into the river? Because we had a Coke in our backpack. And he just looked at me and took the Coke out and threw it in the river.
HAMILTON: Dr. Sue decided Kanzi must've known what the words meant when spoken in that order, but some linguists were skeptical. They said the sentence, throw the river in the Coke might have produced the same response. They said Kanzi might have been reacting to Dr. Sue's body language, not her words.
Sue Savage-Rumbaugh was determined to prove that Kanzi really did understand sentences. So she persuaded him to take a series of scientific language tests, something Kanzi doesn't always feel like doing.
Here's one they videotaped. In it, Dr. Sue is wearing a welder's mask so Kanzi can't see her face. She makes no gestures and she had Kanzi perform unlikely tasks involving familiar items, like pine needles.
SAVAGE: Kanzi, can you put the pine needle in the refrigerator? Good job. Thank you.
HAMILTON: Kanzi was doing what linguists said no ape could do. And later, Panbanisha would perform even better in similar tests.
But linguists still weren't satisfied. They pointed out that humans invent metaphors and figures of speech when literal meanings isn't enough. Dr. Sue says bonobos passed the metaphor test as well. For example, Panbanisha once referred to a visitor who misbehaved with a symbol for monster.
At this point, we're interrupted by a phone call from the bonobo home.
SAVAGE: Kanzi, can you hear me?
HAMILTON: Kanzi just wants to know what's up with the visitors. But pretty soon, the other bonobos are also demanding a turn on the phone.
SAVAGE: Hi, Nathan.
HAMILTON: Then the bonobos decide they want to chat with people other than Sue.
BILL FIELDS: Kanzi, this is Jon. Nyota, are you ready for the visitors to come?
HAMILTON: That last voice was Bill Fields, a researcher who's joined us in the double wide. When everyone finally gets off the phone, Fields tells us another story about Kanzi using language in creative ways. It involves a Swedish scientist named Pare Segridall(ph).
Fields say that one day Kanzi overheard that Pare was bringing bread. Kanzi's keyboard had no symbol for Pare the scientist, so he found Sue's sister, Liz, and began pointing to the symbols for bread and pear the fruit.
FIELDS: Liz got it immediately. She says, what do you mean, Kanzi? Are you talking about Pare or pears to eat? And he pointed over to Pare.
HAMILTON: Fields says Kanzi's upbringing has given him a powerful desire to communicate with the humans in his world.
FIELDS: He wants to share. He wants to do things with people. He wants people to know how smart he is. He wants people to know what he can do. And occasionally, he'd like to be able to tell people to do things for him that he can't do for himself, like go down to the Dairy Queen and get him an ice cream with chocolate on it.
HAMILTON: Which they did, until Kanzi went on a diet. Fields says Kanzi also has developed a skill closely associated with human language. It's called theory of mind, and a growing number of researchers believe it is at least as important as grammar.
Theory of mind means recognizing that other people have their own beliefs and desires. It also allows someone to imagine the world from another person's point of view.
Scientists disagree about whether apes have this ability. But Bill Fields has no doubt. He holds up his hand.
FIELDS: I'm missing this finger. It's just an artifact of working with great apes. So one time when Kanzi was grooming my hand, when he got to where the missing finger is, he pretended like it was there. And then he said at the keyboard, he uttered hurt, as though does it still hurt? I said, oh no, it doesn't hurt. And he kind of patted my hand like that. He was concerned it might still hurt.
HAMILTON: One word: hurt. But Fields says it reveals something about the very nature of language. The power and meaning of words comes from the social context that produced them.
At the Great Ape Trust, the bonobos are constantly finding new ways to strengthen their ties with humans, like talking on the phone or watching videos of their human friends visiting places bonobos aren't allowed to go. Sue says that helps Kanzi and Panbanisha cope with their odd status as creatures who socialize with humans, but are not human themselves.
SAVAGE: They are aware of that, and sometimes it's a sadness. Because they do realize that they can't go everywhere we can go, and they can't do everything that we can do.
HAMILTON: They can't go back to the wild, either. Bonobos in the Congo have been all but wiped out by hunters. And Kanzi and Panbanisha have become too human to live on their own in the wild. The apes are straddling two worlds, and they seem to know it.
Dr. Sue says both Kanzi and Panbanisha like to watch movies that blur the boundaries between humans and apes.
SAVAGE: Kanzi's favorite movies he was very young were Iceman and Planet of the Apes. I guess his favorite movie of all time is Quest for Fire.
HAMILTON: A movie about prehistoric tribesmen.
Dr. Sue says Kanzi and Panbanisha know that we've come to tell their story on the radio. She says that's one reason they were so excited to meet us. At the end of the afternoon, Kanzi asks that we all meet in the kitchen to eat grapes. Dr. Sue says okay, even though she knows we have to catch a plane.
She and Kanzi head for the kitchen. We step into a hallway.
SAVAGE: I've lost the visitor.
HAMILTON: Bill comes out to meet us.
FIELDS: Okay. You can come this way. I have Kanzi out of there.
HAMILTON: We leave without ceremony.
FIELDS: Can you bring your car around just by the door down here?
HAMILTON: Oh, you bet.
Bill says it's better that way. Kanzi hates to say goodbye.
Jon Hamilton, NPR News.
SIMON: Bill Fields also works with a bonobo named Nyota. And he says that taking Nyota out for ice cream and french fries has helped Nyota's language skills.
You can read that story, you can see a multimedia interactive exploring how language works at npr.org, our website.
In the second part of this series, Jon Hamilton discovers what people with autism are telling researchers about language. That's tomorrow morning on Weekend Edition Sunday. I think Nyota will be listening.