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SHOW 903

Episode Open
If Only They Could Talk
Who Needs Words, Anyway?
Number Crunchers
Figure That One Out
No Fools About Tools
Thinking About Thinking


ALAN ALDA: Rocky here understands groups. She knows that this is part of one group, and that's part of a whole other group. Not bad for a sea lion, huh? On this edition of Scientific American Frontiers, we'll be reaching inside the minds of animals.


ALAN ALDA: (Narration) We'll teach sign language to Hamlet the pig.

SALLY BOYSEN: Good boy, Hamlet.

ALAN ALDA: (Narration) We'll see if ravens know what string really means. We'll get monkeys to count, and to pick the right tool. And we'll ask Sheeba to show us a concept.

ALAN ALDA: I'm Alan Alda. Join me now as we meet the Animal Einsteins

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ALAN ALDA: There once was a horse named Clever Hans. Hans was a genius. He could answer general knowledge questions and do arithmetic and he'd communicate his answers by tapping his hoof. One tap for yes, two taps for no, and he could tap out numbers. A committee of imminent scientists studied Hans. This was in Germany around the turn of the century. And they concluded that there was no fraud or fakery. But they couldn't figure out how Hans was doing this. Then, one scientist made a crucial discovery. Clever Hans only succeeded when there was someone in the audience who knew the answers. It turns out the horse was picking up on tiny, unconscious nods that people were making as they counted the hoof taps. All Hans knew was, if I stop tapping when they stop nodding I get a reward. We all love to know what's going on inside animal's heads. And Clever Hans shows what a tough problem it is to design foolproof experiments. But today, scientists believe they are really getting somewhere in finding out what and how animals think.

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PUPPY: That looks stupid, Mom

BITCH: Not as stupid as sheep, mind you, but pigs are definitely stupid.

BABE: Excuse me. No we're not.

BITCH: Good Heavens!

ALAN ALDA: (Narration) It took hi-tech models and banks of computers to make, but at its core Babe expresses an age-old human fantasy -- talking animals.

BABE: Our mom called us all the same.

BITCH: And what was that, dear?

BABE: She called us all Babe.

ALAN ALDA: (Narration) Meet Hamlet.

SALLY BOYSEN: He's a couch-potato pig, aren't ya, huh?

ALAN ALDA: (Narration) He's Hammy to his friends. And meet Hammy's best friend, psychology professor


SALLY BOYSEN: Hammy, Hamlet, do you want a dog biscuit? Hammy, sit. No, further down than that. Further down to sit. There is so much lore and anecdotes around about how pigs are smart and I don't know that we have much empirical or scientific evidence to support that.

ALAN ALDA: (Narration) Four years ago, Sally set out to see how smart Hamlet is. She used three different objects, each with its own sign.

SALLY BOYSEN: Hammy -- ball! Where's the ball?...Good boy, Hamlet.

ALAN ALDA: (Narration) Eventually Hamlet learned to associate signs with objects, but it took a laborious 8 months of training. By the way, Sally was always careful to avoid the Clever Hans effect -- no eye movements or nods or gestures that might tip Hamlet off.

SALLY BOYSEN: Frisbee!... ...Frisbee!

ALAN ALDA: (Narration) Hamlet's memory's pretty good -- Sally hasn't tested him for three years. But simple associations like these are his limit. He can't use the signs in any way, and we can't see his mind at work.

SALLY BOYSEN: There's a whole lot more to naming than just associating even an abstract symbol of some sort or a gesture with an object. He'd need to be able to use that name or that symbol in a lot of different ways that he'd have a different understanding that was beyond mere association.

ALAN ALDA: (Narration) We're on the California coast, at Santa Cruz. Here the animals have a little more to say than Hamlet.

ALAN ALDA: How many tanks do you have here?

RON SCHUSTERMAN: Well, we have two right here, and then there are several back there. You can use this antiseptic here, it's a little foot bath before we go on deck. And these are the objects she'll be working with.

ALAN ALDA: (Narration) I'm here to have a conversation with Rocky, a very friendly sea lion.

ALAN ALDA: Oh all right give me a kiss, ha, ha, ha. That's very nice, that feels good, Rocky.

TRAINER: As soon as you get the OK to start ěballî, you turn them up like this.

ALAN ALDA: (Narration) First I have to learn Rocky's language -- about 25 signs.

ALAN ALDA: You go up and down?


ALAN ALDA: (Narration) Next the sign for ětouch with flipperî, followed by ěgo do itî when I drop my foot.

ALAN ALDA: I almost went in!

ALAN ALDA: (Narration) Now here's ěcubeî.

TRAINER: All right so we're going to merge that with the action signs, so give me a ěflipper touchî sign... okay, that's good, and ětail touchî sign. Okay that's it, they look decent for a first timer.

ALAN ALDA: Decent, nice answer, I probably have some kind of accent. I hope she'll recognize my accent.

ALAN ALDA: (Narration) OK -- let's talk.

TRAINER: Grab a couple of pieces of fish and just toss them in. She knows you are going to feed her.


TRAINER: Okay, now point to your foot. All right, now we're going to give her ěcubeî and ěflipper touchî


TRAINER: Okay, ěcubeîîflipper touchîshe wasn't really too sure about that.

ALAN ALDA: She sure looks cute.

ALAN ALDA: (Narration) Rocky's not happy. She doesn't know what I'm talking about.

TRAINER: Let's do a ball tail touch.

ALAN ALDA: Ball tail touch, OK.

ALAN ALDA: (Narration) Okay, ěballî. Looking good -- Rocky checks for the ball -- and ětail touchî. Oh, no -- she does ěball - fetchî.

ALAN ALDA: Is this my accent getting her confused with the ball, or what?

ALAN ALDA: (Narration) All right let's try again, in my best signing. Ball ń drop tail touch.

ALAN ALDA: There she goes, whoa, far out, bravo, terrific!

ALAN ALDA: (Narration) It's an exhilarating feeling to really get through to an animal.

TRAINER: Do a cube flipper, remember ěflipper touchî?

ALAN ALDA: (Narration) Cube -- flipper touch.

ALAN ALDA: OK, very good, here.

ALAN ALDA: (Narration) Now I'm going to ask a question -- ěFootball -- is it here?î Rocky heads right for the ěyesî button.

ALAN ALDA: OK, bravo. It's great in show business, isn't it?

ALAN ALDA: (Narration) Once Rocky gets used to my accent, it's obvious she really does get it. She knows, at some level at least, what my signs mean, and unlike Hamlet the pig she can use them in different ways. So with Rocky there is at least a brief glimpse into an animal mind. In fact over the years there have been several examples of simple communication with animals.

ALAN ALDA: Give me a kiss.

ALAN ALDA: (Narration) This is Washoe the chimp, in the early 1960s. Watch Washoe make a sign meaning ěopenî. Washoe was raised from infancy by researchers at the University of Nevada.. Eventually he learned to use about 130 American Sign Language signs. Washoe's vocabulary was impressive, but teaching animals artificial language has its limits -- maybe we only get back what we ourselves put in. There's no insight into what or how the animal itself thinks.

TRAINER: C'mon what is it?

ALEX: Key chain.

TRAINER: Good boy!

ALAN ALDA: (Narration) The ultimate expression of artificial language use is Alex the parrot.

TRAINER: What is it?

ALEX: Rock.

TRAINER: Good boy.

ALAN ALDA: (Narration) Alex can distinguish and name different objects...

ALEX: Nail.

TRAINER: Nail, that's right. You're a good birdie.

ALAN ALDA: (Narration) And different colors.

TRAINER: Now tell me what color?

ALEX: Yellow.

TRAINER: Yellow, that's right.

ALAN ALDA: (Narration) He can identify different materials.

TRAINER: What matter?

ALEX: Wood.

TRAINER: Yeah, that's right, very good.

ALAN ALDA: (Narration) Alex can count.

IRENE PEPPERBERG: How many? How many?

ALEX: Two.

IRENE PEPPERBERG: Good parrot, good boy. One, two.

ALAN ALDA: (Narration) And he can also grasp abstract concepts.

IRENE PEPPERBERG: OK can you tell me what's different? What's different?

ALEX Color.

ALAN ALDA: (Narration) In case you're wondering, the researchers are convinced they're not falling into any Clever Hans type of traps that might tip Alex off. Alex can juggle concepts in an astonishing way.

IRENE PEPPERBERG: What color bigger. You know, what color bigger?

ALEX: Yellow.

IRENE PEPPERBERG: Good boy, good birdie.

ALAN ALDA: (Narration) And take a look at this.

IRENE PEPPERBERG: What matter four corner blue?

ALAN ALDA: (Narration) In Alex's personal language, that means ěWhat is the four-cornered blue object made of?î He's never been asked this question before, so this is not a circus trick. There are several four-cornered objects, and several blue objects, but only one that combines four corners and blue color.

IRENE PEPPERBERG: What matter four corner blue?

ALEX: Wood.

IRENE PEPPERBERG: That's right. I've got to go eat dinner, okay, I'm going to put you in.

ALAN ALDA: (Narration) ALEX is the most successful example anywhere of an animal using artificial language.

ALEX: You be good. Bye.

ALAN ALDA: (Narration) Through that language he shows a grasp of abstract concepts like sameness, or the idea of combining qualities. But the big question for researchers is, do animals think conceptually without the help of human-taught languages?

ALEX: I'm sorry. You're a good boy.

ALAN ALDA: (Narration) That's what we'll explore next.

ALEX: I love you.

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ALAN ALDA: (Narration) This is Rio -- the star pupil of

RON SCHUSTERMAN: at Santa Cruz. Ron insists Rio can understand abstract concepts without the aid of any language. Today, she'll show us that she gets the concept of "groups" or "classes". Backstage they set out cards with one of either thirteen letters or thirteen numbers. First, Rio's task is to pick just the letters. Learning the letters was an arduous process. It took Rio thousands of trials over more than a year.

ALAN ALDA: The first time she goes through this, she just sees a bunch of symbols. She doesn't know which one is a letter and which one is a number. Those are terms we use. So, she keeps getting reinforced every time she chooses let's say a letter. Once she's consistent at that

RON SCHUSTERMAN: Then she forms a class

ALAN ALDA: (Narration) To learn numbers, the reward for letters suddenly stops. Rio doesn't like that at all.

ALAN ALDA: It sounded like a complaint.

RON SCHUSTERMAN: It is a complaint. You know, where is the food.

ALAN ALDA: (Narration) No number, no reward. Rio takes a swim break. Finally, Rio starts picking numbers -- and she'll continue as long as she's rewarded. By the way, some letters and numbers have extra features so they're more distinctive. Remember, to Rio they're just shapes that belong in one abstract group or the other. Today, Ron's going to add a new number -- it's actually the number sign.

RON SCHUSTERMAN: Now this is the brand new number

ALAN ALDA: This is a number she's never seen before?

RON SCHUSTERMAN: She's never seen it before, and I'll tell you why if she gets it correct.

ALAN ALDA: (Narration) Rio has to include the number sign in the number group. Right now, Rio's getting rewarded for not picking letters.

RON SCHUSTERMAN: She almost didn't get it.

ALAN ALDA: Yeah, that was really nice, you could see her mind working.

RON SCHUSTERMAN: She uses what we call "exclusion". She knows all the letters. She knows the letter set. Don't go to the letter. So whatever that novel thing is, go to that.

ALAN ALDA: It's a better bet for her.

ALAN ALDA: (Narration) To add a new letter, they first stop rewarding for numbers. Once again, she takes a break.

ALAN ALDA: So now she's in the water, she's thinking, they're switching them on me now.

RON SCHUSTERMAN: That's correct

ALAN ALDA: And if she gets the idea she might go for a.

RON SCHUSTERMAN: It might take a few, it's hard to know, she might take another number.

ALAN ALDA: Okay so now she's had two wrong. She ought to get the idea now.


ALAN ALDA: (Narration) On the right is a number by the way.

RON SCHUSTERMAN: Aha, the old lightbulb is going on.

ALAN ALDA: (Narration) Now she gets the new letter -- n. She knows that 8 isn't a letter, so again she picks the n by exclusion. Okay, not bad Next we're really going to challenge Rio's understanding of the two groups. This time there's a symbol in the center -- and Rio has to find the match from the same group. Now, Rio must be prepared to change the group every time.

RON SCHUSTERMAN: So B goes with J.

ALAN ALDA: Right, B didn't go with 9. By the way, I got that and I wasn't getting a herring.

ALAN ALDA: (Narration) Here's that new number sign she just learned.

ALAN ALDA: Wow, that was great.

RON SCHUSTERMAN: You can almost see her thinking.

ALAN ALDA: (Narration) Then she gets the same number sign again. Now watch what happens.

RON SCHUSTERMAN: But remember she just got rewarded for this.

ALAN ALDA: This is, this is, you're starting to get to me with this. She just got rewarded for choosing the number sign in a different circumstance.

RON SCHUSTERMAN: That's right.

ALAN ALDA: It is now not in the right class.

RON SCHUSTERMAN: That's right.

ALAN ALDA: And she doesn't go for it even though she just got a reward for it.


ALAN ALDA: Okay, okay, this is really making an impression on me now.

ALAN ALDA: (Narration) Ron's research has left little doubt that Rio can work with the abstract concept of "class" or "groups" -- and there's no language involved.

ALAN ALDA: Are you saying, therefore, that in some way these animals are reasoning?

RON SCHUSTERMAN: Yes, I'm saying they're reasoning, and they're reasoning without language.

ALAN ALDA: I mean that seems like an extraordinary conclusion to come to. I mean, I can see how you came to it. But doesn't that strike you sometimes? Don't you say to yourself, "gee, I'm operating on the idea that these animals are thinking and reasoning."

RON SCHUSTERMAN: Oh, I didn't always believe that.

ALAN ALDA: Well it must have, when you finally realized you believed it, you must have said to yourself, what an extraordinary thing to think.

RON SCHUSTERMAN: That's correct. I did.

ALAN ALDA: (Narration) We can only speculate how sea lions in the wild might use this ability to form abstract groups. Ron suspects that classifying helps sea lions sort out the many individuals they encounter, labeling them as friend or foe, family or non-family, and so on. In other words, it's an essential part of being a sea lion.

SALLY BOYSEN: Hi sweetie.

ALAN ALDA: (Narration) Here's

SALLY BOYSEN:, whom we first met with her pig Hamlet. Sally's main work is with chimpanzees, and she thinks they can handle abstract concepts with ease. We're going to run a "hide and seek" experiment using a scale model room and a matching real room that's just a few feet away. Sally says that chimps can get the connection between the two -- that one can be a symbol for the other.

SALLY BOYSEN: Here's our little miniature room. And we have a replica of that cupboard. And a little chair right here, blue tub. We have a miniature tree here.

ALAN ALDA: And this little can here?

SALLY BOYSEN: That's the item we're going to hide. They'll watch as we hide this, like under the blue tub. Then I go into the real room and hide a real can of soda. And then the chimp has to pay attention to where we hid it here and then find it in the same place inside there.

ALAN ALDA: What's the real room look like compared to this?


ALAN ALDA: (Narration) Everything in the model has its full scale counterpart

ALAN ALDA: That doesn't open?

SALLY BOYSEN: Yeah. The chimps know how to open it.

ALAN ALDA: I guess you have to be a chimp.

SALLY BOYSEN: You just go like this. It's kind of an IQ test.

ALAN ALDA: Oh, I see.

ALAN ALDA: (Narration) We're going to be working with strong, full grown animals.

SALLY BOYSEN: You stay out here.

ALAN ALDA: Right. You're going to be in there?


ALAN ALDA: Now, you're safe in there?

SALLY BOYSEN: Sure. Now don't try this at home.

ALAN ALDA: I haven't got a chimp at home.


SALLY BOYSEN: Very nice, okay, she has to get a little rowdy here. This is so much fun isn't it?

ALAN ALDA: (Narration) Sheeba is 13 years old -- raised from age two by Sally.

ALAN ALDA: That was cute.

SALLY BOYSEN: That was very impressive.

ALAN ALDA: You know, I've worked with actors like this before.

ALAN ALDA: (Narration) I have to admit, she's not striking me as much of an intellectual yet.

SALLY BOYSEN: Okay, I've got some real Pepsi for you. All right, where should we hide it? Let's see. I'm going to take this little one. Are you watching me? And I'm going to put it in here. Okay, watch. I'm going to put it right in here. So we put it in here. Should I show you again. Look. I put it right in here. Isn't that cool. I know I have makeup on. See my lips? I know I have different makeup on. Now, see that? We're going to keep on going. Now you stay right here. I'll be right back. I'm going to hide this real one for you. Okay, stay right there. Stay there. Where is it? Where did we put it? In here, right. There's the little one. Okay, go find the real one for me. Hurry. Hurry. See if you can find it.

ALAN ALDA: She gets it opened, too.

JUDY DELOACHE: Here's Big Snoopy and this is his little friend, Little Snoopy.

ALAN ALDA: (Narration) Now look at how a two and a half year old human does in the same experiment.

JUDY DELOACHE: Look I'm hiding little Snoopy

ALAN ALDA: (Narration) This experiment has been tried with hundreds of children.

JUDY DELOACHE: You wait here while I hide Big Snoopy. I'm going to hide him in the same place in his room.

AMOS: And I'll go find him.

JUDY DELOACHE: Okay, Amos, Big Snoopy is ready, can you come find him? Remember he's hiding in the same place in his room that Little Snoopy is hiding. Remember Big Snoopy's hiding in the same place

ALAN ALDA: (Narration) Until about age three kids never get that the model symbolizes the real room.

SALLY BOYSEN: Sheeb, that's where I put the little can, see it? Now I'm going to go hide the real one.

ALAN ALDA: (Narration) So in one way Sheeba is sharper than the average two and a half year old human.

SALLY BOYSEN: Don't cheat, I'll be right back.

ALAN ALDA: (Narration) There's no doubt Sheeba sees the model as representing the real room. And if that isn't abstract thinking, I don't know what is.

SALLY BOYSEN: Okay, I hid it, where is it? Where'd I hide it? Remind me where I put it. Right there! Okay, now go get it for me, hurry, go on. Go hide it, or find it, whatever. Oh, you found it, all right, good work, good work.

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ALAN ALDA: So what kind of monkeys are we going to be working with?

SUE CAREY: These are rhesus.

ALAN ALDA: (Narration) We're in Puerto Rico to investigate the amazing counting skills recently discovered in monkeys. I'm with psychologist Sue Carey, and she's taking me out to a small island just offshore. Called Cayo Santiago, it's home to about 1,000 rhesus monkeys.

ALAN ALDA: These monkeys have been here isolated on this island since when?

SUE CAREY: The 30s. They were brought over interestingly enough for behavioral research.

ALAN ALDA: (Narration) Sue's background is studying how young children think. But lately she's begun looking for the roots of human thinking in monkeys.

SUE CAREY: See them playing in the water? Shall we go up this way?

ALAN ALDA: (Narration) We're going to conduct a simple counting experiment with apples and boxes -- if we can find a monkey that will pay attention.

SUE CAREY: Okay, what we've done here is we've tried to find a monkey that was all by himself. There are no other monkeys around as far as we can see. Then we're going to show him that the boxes are empty. Then we're going to kneel down and I'm going to put two apples in one box and Laurie will put three in the other. And then we'll step back and see which one he chooses. If he chooses the one with three, then he knows that three is more than two. Simple as that. Okay.



ALAN ALDA: (Narration) Laurie shows that her box is empty while the monkey looks on. Sue makes it clear that her box is empty too.

SUE CAREY: Okay, don't look at him anybody.

ALAN ALDA: (Narration) Slowly and deliberately, Sue places 2 chunks of apple in her box. Next, Laurie puts 3 chunks of apple in her box.

SUE CAREY: Okay, walk away.

ALAN ALDA: (Narration) Which box will the monkey go to?

SUE CAREY: Okay, now you see what happened. He went to the one with three.

ALAN ALDA: I suppose this is meaningful if you do it many times.

SUE CAREY: We have done this very experiment -- three versus two -- with 15 monkeys, and 14 out of the 15 went with three.

ALAN ALDA: (Narration) To assure their results were solid, trials were run with several variations.

LAURIE SANTOS: Sit. Go back. Good. Watch. Ready.

ALAN ALDA: (Narration) As Laurie is doing here, sometimes she put her apples in first instead of Sue. And they changed who put in three versus who puts in two. Regardless of the variations, the monkeys went for the box with three. So the monkeys must be counting what goes into each box. And that's not all.

SUE CAREY: Each monkey only sees one trial. That monkey has never been in this experiment before. So I mean that's extremely interesting. He's spontaneously counting the apples. How is he gonna know that one of us in going to put three and the other is going to put two. But he sees apple, he spontaneously counts how many times they go in there.

ALAN ALDA: (Narration) Using a portable "magic stage", Laurie and Sue are now investigating whether the monkeys can also do basic addition. The experiment works like this. A lime is placed on the stage and a barrier put down to block the view. After a brief pause, another lime is added.

LAURIE SANTOS: Monkey, monkey, look, look.

ALAN ALDA: (Narration) One plus one is two -- no magic there. The monkey quickly loses interest. It's videotaped to measure later how long the monkey looked. Now here's another show. It's identical to the first, except for the surprise ending.

LAURIE SANTOS: Watch. Ready.

ALAN ALDA: (Narration) One plus one equals, one? The monkey stares for a long time -- many seconds more than before. Sue believes this means the monkey was surprised -- that it must have known something was wrong. Such îLooking time experiments" as they're called were actually developed to figure out what's going on inside the minds of human babies. When shown non-magical events like this one, 3 month old babies get bored rapidly. But show them an impossible or magical event like this The infants stare and stare. Their fascination with magical events suggests they know the world doesn't work this way. So based on looking time, the monkey was surprised. He must have added the second lime to the first and realized he was shown something impossible. The chimpanzee named "Aye" is a famous example of an animal's awareness of numbers. After years of working with psychologist Tetsuro Matsusawa, Aye can quickly count the dots flashed on a computer screen and indicate with near-perfect accuracy how many he saw. If we freeze this video, you can see there are nine dots on the screen. An instant later, Aye presses the number 9. Aye also can arrange numbers in ascending order. He's faster than any human who's ever done these tests. Sally Boysen's chimpanzees have shown they can solve math problems that would delight a kindergarten teacher. Here, the problem is three plus three. Seven years ago, Frontiers recorded the first-ever attempt at addition by a chimp.

SALLY BOYSEN: How many? Show me. Yeah, six. That's the right answer. Good girl, there are six peaches out there.

ALAN ALDA: (Narration) Watch what happened when numbers were used instead of peaches.

SALLY BOYSEN: Here's another one.

ALAN ALDA: (Narration) This is Sheeba, by the way -- the same chimp we did the model room experiment with.

SALLY BOYSEN: Okay, how many was that? Can you pick? Show me. Four! Yeah!

ALAN ALDA: (Narration) Eventually, this chimp could add up to nine. She really seemed to understand what numbers were all about.

SALLY BOYSEN: How many of these do I have? Two bananas. Right, there's two bananas here.

ALAN ALDA: (Narration) That's not all Sally's chimps understood about numbers.

SALLY BOYSEN: First I cut this. One more time. And now I have this little weensy piece. It's a fourth of a banana. Right.

ALAN ALDA: (Narration) Sally discovered that her chimps could even grasp the sophisticated concept of fractions.

SALLY BOYSEN: I've got another fourth, that's right, there it is.

ALAN ALDA: (Narration) So the overall conclusion is, humans just don't have a monopoly on the world of numbers.

ALAN ALDA: We are accustomed to thinking of ourselves as being so far removed from the other animals in tasks like that. It's shocking to realize that we're much closer cousins than we thought.

SALLY BOYSEN: Yeah, and for years we've thought about ourselves that way. Even Aristotle said, "man is rational because he counts".

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ALAN ALDA: (Narration)

BERND HEINRICH: has a passion for birds. When he's not teaching, you'll find him out behind his house -- where he keeps an aviary filled with ravens, the largest type of crow. When it comes to brains, crows have an A-plus reputation.

BERND HEINRICH: The crow family has always been thought to be extremely intelligent. Although the interesting part is, why do people think they're so intelligent when in fact there aren't even any real tests that have examined that. And so that's the challenging part to find out, you know, how intelligent are they? And how do you know that they're intelligent?

ALAN ALDA: (Narration) One of the best ways to test an animal's intelligence is to see how it handles a difficult situation for the first time. And today, this 10 month old raven is in for a surprise. What will the bird do when dinner is tied onto a string, and the string tied onto a branch? String is something the raven has never seen before -- and at first the bird is too scared to go near it. Bernd lures the raven up to the branch to get it focused on the meat. The fact that the raven tries to fly away with the meat shows it doesn't understand that string joins things together. But once it's had a taste, it's determined to get another bite.

BERND HEINRICH: Well, now that we've seen that you tried to fly off with it. Well, that doesn't get the meat. So now what? With this new strategy, the meat's moving below, but it's not getting any closer to the Raven's mouth. Now there's a breakthrough. It's a totally creative solution -- raise the meat step by step -- but still not perfect... The raven knows it's on the right track. Then as a test, Bernd shoos the Raven away.

BERND HEINRICH: He's not going to fly off with it now, he knows it's attached.

ALAN ALDA: (Narration) Only seven of the ten ravens Bernd has tested could solve this problem. So it's unlikely that the solution is genetically programmed into the birds. Bernd concludes that the successful birds had to be thinking the problem through.

BERND HEINRICH: There wasn't any very long trial and error learning. If there was any learning it was extremely quickly. And I could only explain that that he had some concept of what was happening, of what he was doing.

ALAN ALDA: (Narration) Next stop Harvard, where before we can film, the animals have to get used to me and the camera. They're little South American monkeys called cotton topped tamarins.

ALAN ALDA: Are they getting used to me here?

MARC HAUSER: The animals started off when you walked in the room giving what we think of as alarm chirps. They're chirps that are evocative of being a little bit afraid, curious, investigative. And now they're giving basically sort of low level chirps. They're just curious now. So they've really gotten used to the fact that you're in the room.

ALAN ALDA: My ratings have gone down in just a minute or two.

ALAN ALDA: (Narration) Marc Hauser, like Bernd Heinrich with his ravens, also dreams up ingenious experiments to probe how animals think.

ALAN ALDA: This is the gravity experiment? How does this work?

MARC HAUSER: That's right. This is an experiment which is going to determine what kinds of expectations the animals form when something drops. And the way we're going to test that is we're going to show them that these ending pipes are empty -- there's nothing inside of them. And then we're going to close the doors. And then we're going to insert an opaque tube up here. And we're going to take a piece of food. And we're going to wave it in front of them so that they track it. And then we're going to drop it and we're going to let them search.

ALAN ALDA: (Narration) Which door the tamarins open up first should reveal where they expected the food to drop. Here's our subject. First he gets a chance to look behind all the doors.

ALAN ALDA: He's checking to see that they're empty?

MARC HAUSER: Exactly. So we're making sure he knows they're empty. We're going to close the doors. And now we're going to give him a track.

ALAN ALDA: (Narration) The monkeys love fruit loops, and "giving him a track" means waving a piece in front so the tamarin follows it. That was quick. Let's see it again. The tamarin goes for the door directly below where the fruit loop was dropped. So he expected gravity to apply.

MARC HAUSER: Let's try this again now. Same configuration.

ALAN ALDA: (Narration) Even after 20 trials, the tamarin still makes the same error.

ALAN ALDA: He doesn't learn anything about the tube.

MARC HAUSER: Absolutely nothing. And this reinforces the view that he's got such a strong idea in his head that this is where it's got to fall that even though he's never getting reinforced there he's not going to switch his strategy.

ALAN ALDA: (Narration) Now Marc tries to teach the tamarin about the tube by using a transparent one. This time when the fruit loop falls, it's path will be obvious. This time he gets it.

MARC HAUSER: Now, the critical question is, having had that experience, and being reinforced correctly now on the first go, will he now take that experience and generalize that to this new experience?

ALAN ALDA: (Narration) The new experience is actually the original setup with the opaque tube. The tamarin fails again. He's learned nothing. But take a look at what happens with another variation of the experiment. This time the whole tube apparatus is on its side. The tamarin gets the correct answer on the first try. Without the distraction of gravity, it was able to think about the tube.

ALAN ALDA: When we say thinking, do we mean thinking almost fully conscious thinking?

MARC HAUSER: Showing that they can track objects and either fail in that task or pass that task shows they can make an estimation of what happens when something disappears out of sight. Now in one sense, that shows that they're able to maintain an object that's gone in their mind. So on some level, that means they're forming some kind of representation. Some kind of image of what that object's like in their head.

ALAN ALDA: (Narration) Marc's experiment is a fascinating one, because it shows the limits of tamarin thinking. When gravity's involved, they get overwhelmed by how they know it works. But strip gravity away and underneath lies logical thinking. Just like the ravens.

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ALAN ALDA: (Narration) It's well known that chimpanzees can use simple tools. In the wild, for example, they've been observed cracking open nuts with rocks. And here in captivity, they use sticks to get at honey.

ALAN ALDA: Do you want a stick?

ALAN ALDA: (Narration) This use of tools seems very human -- kind of smart like us. It's even led to speculation that apes learn skills and pass them on, just as we do.

ALAN ALDA: How did they learn to do this? Do they learn the same way we do?

MICHAEL TOMASELLO: Well, there are a couple of different theories about how they might go about learning it. On the one hand, I would say that they do go about learning in it very much the same way that a child would. They are exposed to the tool. They have a problem in front of them and they, either some combination of trial and error or insightful problem solving. And in many cases, I do believe they employ insightful problem solving in the sense that they don't have to try out ever possible solution. They can look at the problem and see which one might work better.

ALAN ALDA: (Narration) Can animals really think about tools? That was the question which

MARC HAUSER: set out to explore back at Harvard -- working with his cotton top tamarins. Both of these blue canes are tools -- but if you could only pick one to hook a marshmallow, which would it be? This tamarin knows the right answer. After getting a chance to look from above it goes for the cane with the marshmallow inside the hook. After weeks of practice, the Tamarin is used to using thin blue canes. But here comes something new A blue cane that's too fat to grasp versus a thin cane that's red -- a color the tamarin's never seen in a tool. The Tamarin went straight for the easy one despite the strange color. The point of the experiment is to find out whether Tamarins understand which features of a tool are important to its function. The nobbly green triangle is certainly weird looking -- but it's set up to use more easily than the familiar blue cane. The Tamarin sized things up right away.

MARC HAUSER: The only thing we were looking at was the first time they experience that change in a feature. The reason for that was we didn't want to teach them to pick the right thing. We wanted to see what they would spontaneously do.

ALAN ALDA: (Narration) No matter what new tools are presented, on the first try the Tamarin always picks the one that would get the reward most effectively. Here's another tool brain teaser. You can use cloth to pull in a marshmallow -- if you choose the correct one. It took the Tamarin a few days of practice before it was consistently going for the continuous cloth. Now Marc wants to know what it learned. It might have just learned to avoid the cloth with the "visual stripe", so Marc tries confusing things by adding an extra band of color to each cloth. On the first try -- after a moment of thought -- the tamarin spots the continuous one. Here's the toughest case of all -- where the break in the cloth is wavy not straight. It's not easy to see which cloth is continuous. But for the tamarin, no problem.

MARC HAUSER: You're a genius. They seem to be able to attend to those aspects of the problem that really matter in terms of solving the problem, excluding changes that we try to throw at them that really don't make any difference whatsoever.

ALAN ALDA: (Narration) So once again, there's a surprising depth of thought inside an animal mind.

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SALLY BOYSEN: Okay, we're going to try and suit you up here.

ALAN ALDA: Why am I putting this on?

SALLY BOYSEN: Well, we're going to try and turn you into a little bit of a scary person.

ALAN ALDA: It's going to be pretty scary to the fashion police when I put this on over my sweater

SALLY BOYSEN: That's true, well, this way you're going to look a little bit more like one of the veterinarians who might be coming in to do, say, the chimp's annual physical. And they really don't look forward to that too much.

ALAN ALDA: (Narration) Sally Boysen and I are about to play an elaborate mind game with some chimpanzees.

SALLY BOYSEN: So now you've got the scrub, the mask and then we're going to give you the ultimate frightening weapon.

ALAN ALDA: Which is?

SALLY BOYSEN: The tranquilizing gun.

SALLY BOYSEN: And look, it matches your scrub.

ALAN ALDA: I like to be accessorized.

SALLY BOYSEN: Okay now, as we come out

ALAN ALDA: (Narration) The subject of our experiment is a chimp named Daryl. That's him up on the walkway -- and right now he thinks I've come for him.

SALLY BOYSEN: We're gonna hide. So come on in here, over by that wall.

ALAN ALDA: (Narration) Actually, we're going to make Daryl think I'm after another chimp named Kermit -- who's still indoors, and therefore doesn't know the vet's here.

SALLY BOYSEN: We've got to let him calm down a little so that he's sure that it's not gonna be him. He's got to get used to this. Because we want him to calm down enough so that he's not distressed.

ALAN ALDA: (Narration) We're going to observe how Daryl reacts when Kermit's let out -- to see if Daryl warns his friend that I'm here.

SALLY BOYSEN: Daryl, Daryl. It's all right. Come here. Daryl, Daryl, you're okay.

ALAN ALDA: (Narration) The big question we're asking is whether chimps are aware of what other chimps know or don't know. If they have this awareness, it would mean they "think about thinking" -- something most scientists believe only humans can do.

SALLY BOYSEN: So, we're going to kind of pretend that we're like right here, and you want to kind of crouch a little. As though you're going to get this guy next door.

ALAN ALDA: (Narration) As the door to Kermit's cage is opened, Daryl cries out -- and Kermit stops dead in his tracks. Minutes later we run the experiment again. This time Kermit is already outside and can see for himself that I'm coming to get him. He's clearly upset. But now, up above, Daryl is silent -- a big difference from before.

ALAN ALDA: He doesn't let out a call

SALLY BOYSEN: He doesn't have to because they both know and in this case it's every man for himself. They both have knowledge of the situation. So it's not necessary. And if you will, maybe he's aware that Kermit already knows so I don't have to tell him anything.

ALAN ALDA: You know, when you put it in high class terms like that, that he's aware of the state of mind of the other chimp, it really sounds extraordinary. It sounds like big news. And I can imagine people being very reluctant to take that without a lot of testing. Because it means they're more like us than we thought they were.

SALLY BOYSEN: I think the chimps are capable of showing us much more. And our limitations are our own inadequacies as humans to design an experiment that will show that.

SALLY BOYSEN: Kermit, Daryl

ALAN ALDA: (Narration) By the way right after the experiment, we let Daryl and Kermit know that we were only playing.

SALLY BOYSEN: See, you got the response and now he wants to play.

ALAN ALDA: (Narration) In the future, Sally wants to find out when chimps develop an awareness of the mind.

JANET ASTINGTON: We're going to have a little snack now.

ALAN ALDA: (Narration) Humans don't become aware of what's going on in the mind until around age three -- as this demonstration illustrates with two and a half year old Jacob and a juice box.

JANET ASTINGTON: What's in the box?

JACOB: Juice

JANET ASTINGTON: Look at that. What are they?

JACOB: Ropes

ALAN ALDA: (Narration) Jacob calls the ribbons ropes, which is fine because it's the next question which counts.

JANET ASTINGTON: What did you think was inside the box before I turned it over?

JACOB: Ropes


ALAN ALDA: (Narration) Jacob is unaware that just seconds ago he was sure it was juice. And, unlike the chimp Daryl, Jacob also believes that if he knows something, so will everyone else.

JANET ASTINGTON: Jesse hasn't seen inside this box. What would Jesse think was inside before I turn it over?

JACOB: Ropes

ALAN ALDA: (Narration) So it seems that adult chimps can think more about the mind than young humans. And based on our next experiment, so might tamarin monkeys.

MARC HAUSER: Okay, so here's how it runs. A tamarin will be sitting in that box over there and an experimenter will be standing over here. An actor will come in eating an apple.

ALAN ALDA: That's me?

MARC HAUSER: That's you, ah, eating an apple.

ALAN ALDA: I can do that.

MARC HAUSER: You can do that.

ALAN ALDA: I actually got a lot of good reviews for eating an apple.

MARC HAUSER: You've got credentials, yeah, I want to see the CV. So you come in eating an apple, and then you give the tamarin a little piece.

ALAN ALDA: (Narration) As the play develops, we'll be closely watching the reactions of our audience -- the tamarin -- to see if he's surprised.

ALAN ALDA: I'll see you opening night

ALAN ALDA: (Narration) The play opens while I'm offstage. Marc shows the tamarin that both of the boxes are empty. And now it's time for my entrance.

ALAN ALDA: Howdy Bub. Uhm, good. Good apple. Want some.

ALAN ALDA: (Narration) Right away my audience is hooked.

ALAN ALDA: I'm going to put this away in here; cover it up. See you later.

ALAN ALDA: (Narration) Now, while I'm offstage again, Marc does a little switcheroo with the apple. This is one of those looking time experiments, so the animal's surprise will be gauged by how long it looks.

ALAN ALDA: Hmm. Where's that apple. I'd sure like some more of that apple. I think I'll go in here.

ALAN ALDA: (Narration) When I look in the empty box, the tamarin pays no attention -- there's no surprise in what I've done.

ALAN ALDA: The tamarin saw me leave the room after putting it in this box. If it's a really smart tamarin, it would expect me to come back and look for it in this box. If the tamarin only has a sense of what he or she believes or knows, then they'll expect me to look where they know the apple is.

ALAN ALDA: (Narration) So let's try that now.

ALAN ALDA: Ymm, good apple. Want some? I'm going to put it in here and I go.

ALAN ALDA: (Narration) This time when I come back, I do something surprising.

ALAN ALDA: Ymmm. Sure could use another bite of that apple.

ALAN ALDA: (Narration) I shouldn't know this, and the tamarin stares three times longer than before.

ALAN ALDA: That was a big reaction. He stood up. How do you know they're not looking longer because their mind wanders at that moment or something or there's a noise over there or something like that?

MARC HAUSER: What we try to do is test a number of animals in exactly the same conditions. And so what we're hoping for is convergence. That all the animals will show very similar patterns given the manipulations we do.

ALAN ALDA: So I guess I'll put this apple in the box and cover it up.

ALAN ALDA: (Narration) Now a third variation of the show. This time I stay in my seat while Marc switches the apple -- so if the tamarin's thinking about what I'm thinking it should know that I know the apple's been moved.

ALAN ALDA: Hmm. Sure would like some apple.

ALAN ALDA: (Narration) Now when I reach into the second box, the tamarin isn't very surprised. Here's the last variation of the show.

ALAN ALDA: Okay, putting this in here.

ALAN ALDA: (Narration) Once again, I witness Marc switching the apple. But this time I do something surprising when I go back for another bite -- as if I didn't know what Marc had done right before my very eyes. The tamarin looks for a long time -- so it must be thinking about what I know and what's in my head.

ALAN ALDA: How different are we from these other animals. Are we just vastly, radically different? Are we a total innovation in evolution? Or does this show connections, threads that go back.

MARC HAUSER: No animal is doing calculus. No animal is writing Shakespeare and so forth. Those are vast differences. But what I think seems to be revealing itself now over time is that at the core, we share many of the same principles of thought and knowing.

ALAN ALDA: (Narration) Researchers like Mark Hauser and Sally Boysen represent a new era of investigating animal minds. Their approach depends on exquisitely designed experiments that tease out exactly what the animal thinks. And yes -- they do think -- they are Einsteins in their own way.

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