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CHIMP
MINDS
ALAN
ALDA Hello and welcome to Scientific American Frontiers. I'm Alan
Alda. Tonight we're going to be visiting relatives, spending time
with an engaging if unruly bunch of cousins that we formally broke
up with about 6 or 7 million years ago. I'm talking about chimpanzees
of course, with whom we share almost all of our genes but not a
lot of our lifestyle. Which raises a fascinating question. If we're
so much alike under the skin, what makes us so different? Or put
it another way: how much of what we fondly imagine to be uniquely
human, isn't? To find out, we're checking in with a bunch of youngsters
who are learning to fish… for ketchup. We ask if chimpanzees
raised by humans think more like humans… And we wonder if a chimp
finds it odd to use a bird as a screwdriver. That's all coming up
in tonight's episode, Chimp Minds.
TERMITE
FISHING
ALAN
ALDA (NARRATION) It's 9:30 in the morning and time for Hank to lead
the way into his handsome new domain at the Lincoln Park Zoo in
Chicago. All seven chimpanzees — including three youngsters — have
only recently come here from their previous home in Florida. There's
plenty for them to do in their new environment, which has both indoor
and outdoor space. But after a leisurely stroll to pick up the apples
and carrots just tossed here by the keepers, several of the chimps
head over to one corner, where there's a realistic-looking termite
mound. In the wild, chimpanzees often fish in mounds like this with
sticks, hoping to snare a tasty termite snack; and fishing in the
holes in the artificial mound has quickly become a popular sport
with the Lincoln Park chimps — unless they're distracted by early
morning visitors.
ELIZABETH
LONSDORF So you can see that from this side the holes are not obvious
where they are. It looks very much like a natural termite mound.
So initially when they were learning this, they had to figure out
which of these depressions were actually holes.
ALAN
ALDA (NARRATION) Elizabeth Lonsdorf has spent many hours watching
chimpanzees fishing for termites, mostly in the place the phenomenon
was first recorded — by Jane Goodall some 40 years ago. Goodall's
now legendary observations of chimpanzee behavior at Gombe National
Park in Tanzania had not gotten off to a good beginning. The chimps
were proving elusive.
JANE
GOODALL I couldn't get near them until one never-to-be-forgotten
day I was walking through long wet grass after a very frustrating
morning, and through the vegetation I saw this dark shape squatting
on this golden-colored termite mound, peering and peering. And I
saw… he had his back to me, he was picking pieces of grass and clearly
poking them at the termite mound, I just couldn't quite see and
I didn't dare move, and he's obviously picking something off. And
I saw him reach out and pick a twig and strip the leaves, and that's
so exciting because we used to think we were the only creatures
on the planet who used and made tools.
ALAN
ALDA (NARRATION) Since Jane Goodall first noticed chimps fishing
for termites, they've been seen using tools for other things — cracking
open nuts, for example. What's more, different communities of chimps
use different tools for different purposes — so while one group
hammers at nuts to crack them, another doesn't. Some groups fish
in termite mounds, while chimps in other communities ignore them.
So chimps not only use tools like humans, they also — like humans
— have behavioral traditions, passed down from generation to generation.
By 1998, when Elizabeth Lonsdorf first went to Africa to study chimpanzees,
this notion that they have behavioral traditions akin to human cultures
had become widely accepted.
ELIZABETH
LONSDORF So that in itself fascinated me and I said, OK, I want
to do something about that. And where that led me was really to
try to understand how these cultures are maintained in a community,
how they are passed on.
ALAN
ALDA (NARRATION) Elizabeth began what was to become a three-year
study of a group of chimpanzees in Gombe, including a pair of infant
twins as they learned termite fishing from their mother.
ELIZABETH
LONSDORF This is their mother Gremlin. And you can see a little
white tail tuft there? That's a chimp behind. So there's two babies
on her belly that are just nursing, this is their first real interaction
with tool and the mound. And they kind of just reach out if the
tool's in front of them.
ALAN
ALDA I see her hand grabbing on.
ELIZABETH
LONSDORF Yeah, reaching to mom's mouth, those type of things, actually
at this stage they could actually be bit by a termite, and if mom
drops one on their head, they'll get bit by a termite. This is the
twins the following year, and you can see they're off their mother's
belly, they're much more alert, and this is when they really begin
to bug her and they're really intent on learning this. And notice,
it's important that she is not teaching them, she's not helping
out in any way, she's actually annoyed that there's a little critter
on her head. And the youngster's stealing termites off of her arm
kind of getting in the way, watching very closely. So I think most
things about this are learned in some way.
ALAN
ALDA (NARRATION) Learned — but not taught. Through all her hours
of watching youngsters picking up the art of termite fishing, Elizabeth
never once saw the mom's do any actual teaching — an important difference
from most human cultures, which invest a lot of effort in passing
on learned skills from one generation to the next.
ELIZABETH
LONSDORF This is the twins with their older sister and you can see
they're really starting to but her now and really intent on learning
this skill
ALAN
ALDA They're really watching carefully now.
ELIZABETH
LONSDORF This is typical piece of social interaction you see on
the termite mound in the wild and also here at our termite mound.
There's lots of wrestling over tools and…
ALAN
ALDA But she already knows that the stick is associated with eating
the termites.
ELIZABETH
LONSDORF She may. She may also just think, my sister has something
cool she's playing with. But here it looks like she knows that that
stick is important for some reason to get inside of the mound.
ALAN
ALDA (NARRATION) The most striking of Elizabeth's observations was
that males learned very differently from females.
ELIZABETH
LONSDORF Here's a nice example of a male. He kind of fusses with
the mound, he's interested, but then he kind of much rather go off
and play. He's going to bug other individuals, he's stomping wanting
to get into a play bout with somebody. He steals his mother's tool
here, that's being pretty disruptive. And just to placate him, she'll
tickle him a little bit, that's a tickle. She plays with him just
enough to kind of get him to go away. But he's running around the
mound wreaking havoc essentially.
ALAN
ALDA (NARRATION) It was a whole year later before this young male,
called Fudge, finally decided to settle down and focus.
ELIZABETH
LONSDORF Now, he's almost three and a half, is when he's being as
attentive as the twins were at one and a half. So that's the sex
difference. Girls are really paying attention really early on, boys
not until two years later.
ALAN
ALDA (NARRATION) This is another three and a half year old male,
Samson.
ELIZABETH
LONSDORF He's trying to make a tool, this is the first time I saw
him trying to make a tool. And he's kind of doing it OK, he makes
something very short. But then he swipes the surface of the mound.
So he's gotten that he needs the mound, he needs a tool, he hasn't
gotten the hole part yet.
ALAN
ALDA He doesn't know about the hole. Just brushes it across.
ELIZABETH
LONSDORF Yeah, just brushes it across and magically expects termites
to appear, and they don't, and he gives up.
ALAN
ALDA (NARRATION) And this is Titan, another male, who finally gets
it at age five and a half.
ELIZABETH
LONSDORF And you can see he's fishing quite successfully. Important
to note — he's five and a half. Females can do this at three and
a half. So that's kind of one of the main conclusions we have from
our study: females learn in up to two years earlier; once they learn
it they're actually better at it. We measured the number of termites
that they got out per dip. So females were getting more termites
out per dip. And then also the females tended to mimic their mother's
technique. Males completely did their own thing and they all preferred
short tools. Short tools are easier to get in because, you know,
you have to progressively thread it down there; they're also though,
less successful at it. You get less termites out and you have a
higher failure rate if you have a shorter tool.
ALAN
ALDA What, males are just inherently dumber, I just don't get that.
ELIZABETH
LONSDORF I think it's just a path of least resistance.
ALAN
ALDA (NARRATION) Exploring this male-female difference was one reason
Elizabeth now watches the Lincoln Park Zoo chimps from both outside
and inside their termite mound — which doesn't actually contain
termites at all, but tubes of mustard or ketchup — low calories
treats that are easier for the keepers to handle than termites.
The mound is baited every other day and at random times, so the
chimps aren't ever quite sure if it's worth a visit or not — unless
they hear the keepers underneath.
ELIZABETH
LONSDORF So they just baited it. And you can see Chuckie, our young
female here is the one going to the top. She's one of the better
termite fishers. She's got a nice, pretty nice tool there. There
she goes. She's testing — I don't think that one's full yet, the
keepers are underneath right now. There she goes. See?
ALAN
ALDA Yeah, she got some.
ELIZABETH
LONSDORF So, in between, when she walked away a little bit there,
the keeper got that tube on.
ALAN
ALDA (NARRATION) The mound was first baited about two months ago.
ELIZABETH
LONSDORF When we first baited the termite mound the very first day,
one of the young males was the first to kind of realize that there
was food in there. He walked by the mound and kind of attended to
it and sniffed and he could smell something different. The he walked
right up to the mound, put his nose in a hole, sniffed, you know,
big sniff, OK there's something in there. Then he stuck his tongue
down the hole. Then he tried actually to bite the mound itself like
the mound might all of a sudden be made out of cotton candy or something.
And then he did get a small tool made out of hay here, or a small
twig, and dropped it, and tried to put it in but he dropped it,
he lost it.
ALAN
ALDA (NARRATION) Today, that same young male, Optimus, still seems
not to have quite figured out the appropriate size for a tool —
and soon reacts in characteristically male fashion. Meanwhile Chuckie,
the young female, puts on a virtuoso display.
ELIZABETH
LONSDORF Now this is an individual who often gets forced off the
mound when she's being really successful and also the chimps will
often take her tools. She tends to make really good tools, the other
chimps will take them. And she kind of throws up her hands and goes
and gets something else. She's a little girl — there's nothing she
can do about it. It's the difference in their kind of skill level
that's interesting. As you can see, our alpha male is nowhere near
the mound, he's over there.
ALAN
ALDA Now what is that, he doesn't like to associate with the girls
or what is it?
ELIZABETH
LONSDORF No, I just think he's not interested in doing a task that's
really hard to get a treat. He would rather just hang out.
ALAN
ALDA (NARRATION) Now, it's time to do a little repairing of the
male ego. Male chimpanzees may have very good reasons in the wild
for their poor study habits and clumsy fishing skills — and that's
because while the female chimpanzees are quietly fishing for termites,
male chimps are often off noisily hunting for monkeys. Monkey meat
is an important protein source for males, which they don't share
with the females. So for a young male, rough and tumble play is
more important than practicing his fine motor skills… while for
a female, extra protein comes from a deft touch while termite fishing.
Back at our ketchup mound, almost everyone except the alpha male
is settled in, even including Optimus, who finally has a tool that
works… only to have it promptly stolen.
ELIZABETH
LONSDORF The individual that just took his tool is Cashew, who's
an adult female and her son is next to her, swiping her ketchup
from her. So he is not yet really into fishing on his own, he would
rather mom do the work and he would rather steal. But notice, she
is not offering it to him, she doesn't, you know, really seem to
want him to have it, but he's just in a good place to get it from
her. Behind them on the mound is Nana, she doesn't have any children
on this mound, she's a young female, she doesn't have kids yet,
she's quite a good termite fisher, she does it very often and she
was the one that first after we baited was the first to get food
out.
ALAN
ALDA (NARRATION) So it was Nana who was the founding genius of the
Lincoln Park cultural tradition of mustard-and-ketchup fishing She
also has a liking for Chuckie's tools… Since Nana's breakthrough
discovery all the females have become accomplished fishers. And
Chuckie, as she always does, patiently sets about making a new tool.
ELIZABETH
LONSDORF What she might do is break off that nice thin piece which
is a perfect tool. Instead of those big, strong branches, she pulled
off a really thin piece, that's a perfect tool for this behavior.
ALAN
ALDA (NARRATION) But while Kipper goes on swiping ketchup from his
mother, the ever-resourceful Chuckie has already decided she needs
a new supply of tools — perhaps to insure against future thefts.
ELIZABETH
LONSDORF Oh, she's got a bunch of them. She has a couple of options
now. So you can see a lot of opportunity or learning all around
the mound. They can watch or steal from another individual, like
Kipper is there with his mom, can do a lot of testing out of different
tools. And you can see how teaching maybe isn't necessary. I mean
maybe you pick up enough from watching it's really not worth the
effort of doing any active demonstration.
ALAN
ALDA (NARRATION) While watching her chimps in the wild, Elizabeth
always wished she could see inside the termite mounds. Now she can
— and she plans one day to make the tubes inside bend and twist
like real termite holes to see how the chimps figure them out.
ELIZABETH
LONSDORF One of the things we might do instead of making the tubes
more difficult first is to make the substance they're getting out
more difficult. So imagine mealworms instead of ketchup. Imagine
putting them in there. That's not going to be as easy as ketchup
because they're going to get knocked off the tool, they're not going
to stick as easily maybe. So that's what's so nice about this being
so manipulable. We can actually manipulate the difficulty of the
foodstuff as well as the tube.
ALAN
ALDA Mealworms… I'm just so glad we split off from their ancestors.
ELIZABETH
LONSDORF We just can't do termites…
ALAN
ALDA (NARRATION) Elizabeth Lonsdorf has found intriguing parallels
between how chimps and humans learn — with the boy-girl differences
especially striking a chord in anyone who has raised the human kind.
But the fact that chimps don't teach also highlights a crucial difference
between us and them, and may be one of the reasons why human cultures
are so dynamic, while among chimpanzees what you see is literally
what you get.
ELIZABETH
LONSDORF This aspect of studying chimpanzees interests me because
I think it really brings apes and animal behavior alive for people,
they realize that there's these fascinating differences, and they
become more concerned. Well, what if these chimps that termite fish
go away? Then we've lost that culture and it's gone. So it's a really
nice way to draw conservation into studying animal behavior too,
because as you lose communities, you lose some of these things that
might be quite unique to that community.
ALAN
ALDA (NARRATION) In the new primate center at the Lincoln Park Zoo,
the termite mound is almost as strong a draw for the public as it
is for the chimpanzees. ELIZABETH LONSDORF So, you want to try it?
ALAN
ALDA Oh, I can't wait. I'm not going in there with them, am I? ELIZABETH
LONSDORF No, no, no.
ALAN
ALDA (NARRATION) Chuckie was the expert, so I'm copying her.
ELIZABETH
LONSDORF It goes deeper.
ALAN
ALDA It does?
ELIZABETH
LONSDORF Yeah, that's one of the hard ones.
ALAN
ALDA You mean, I might not actually be smarter than a chimp?
ELIZABETH
LONSDORF They've had more practice.
ALAN
ALDA Thanks for trying to make me feel better. Wait, maybe I have
the wrong end.
ELIZABETH
LONSDORF Maybe come at it from the front. There you go.
ALAN
ALDA Oh wow.
ELIZABETH
LONSDORF It's a hard one, kind of a down and up one.
ALAN
ALDA Yeah, but I needed my mom to tell me how to do it.
CHIMP
SEE, CHIMP DO
ALAN
ALDA (NARRATION) The chimps we've seen so far were raised with little
contact with humans. But the chimps at this chimpanzee sanctuary
in Florida are different.
TINA
OK Grub, Grubby…
ALAN
ALDA (NARRATION) The six animals here made cute pets or performers
as infants. Then they became big, strong, and unwanted. Around the
nation there are now several sanctuaries like this, where discarded
chimps can live the social and active lives their minds deserve.
But their presence here provides an opportunity for a psychologist
from Florida Atlantic University, David Bjorklund.
DAVID
Bjorklund These chimpanzees in particular have a different rearing
history than wild chimpanzees. One fascinating thing about them
is from early on, the ones I'm working with anyway, have had significant
human interaction. In many cases treated much like human children.
TINA
OK, Grub, here you go. Here's the tool you're going to use, Grub.
ALAN
ALDA (NARRATION) And like human children, they get plenty of toys
to play with — though 9-year-old Grub seems a bit baffled by a stick
and plastic washboard.
ASSISTANT
Watch what I do. Doesn't that sound pretty? Okay…
ALAN
ALDA (NARRATION) But then he's shown what they can do.
ASSISTANT
Do it again. Watch…
ALAN
ALDA (NARRATION) Grub is clearly fascinated — and after a wait of
ten minutes to allow the demonstration to evaporate from his short-term
memory, he's given the washboard again. And this time… Now comes
the real test. Grub is given four new objects. First, the experimenters
check to see if Grub may have come across things like this before.
Well, he's interested — but doesn't seem to have any ideas about
what they may be used for.
ASSISTANT
Watch this…
ALAN
ALDA (NARRATION) Grub is very attentive, as usual.
ASSISTANT
Watching? Here we go…
ALAN
ALDA (NARRATION) Ten minutes later, he's given back only the trowels.
Right away he gets it.
DAVID
Bjorklund He saw the cymbals and Now he's generalized it to the
trowels. Very different shape, different handle. He's really very
happy about it, too. We think that that shows he has not just learned
a specific behavior, but he's generalized, he's learned a concept,
he's generalized the concept.
ALAN
ALDA (NARRATION) David Bjorklund believes that — at least in chimps
raised in human society — this ability to generalize a concept suggests
a more sophisticated way of learning than simply direct imitation.
Bjorklund's team has also tested whether chimpanzees have a concept
in their minds of how the world works — including the basic notion
that inanimate things are fundamentally different from living —
or once living — things. Here's a stuffed hawk being used as sandpaper
— an animate object being used as an inanimate one. Will 4-year-old
Noelle find this more intriguing — odder — than the plastic hammer?
She's given a choice as to which to investigate further — and it's
the hawk as sandpaper. Next up, a rock treated as a pet, versus
a rock as a rock. Again, Noelle can choose which one she finds the
more interesting. And sure enough, it's the rock as pet. So far,
Noelle's choices could be explained if she just likes anything animate
— either the object itself, or its treatment. But now for the first
time she's facing some "animate-ness" on both sides -- blackbird-pet,
versus blackbird-screwdriver.
DAVID
Bjorklund Time.
ALAN
ALDA (NARRATION) But she still gets it -- blackbird-screwdriver
was the weird one. So far it's a solid worldview. Now comes the
toughest challenge. Inanimate log, treated like animate pet… up
against a powerful combination — animate duck, treated like an animate
object. That's a kind of double dose of animate-ness.
ASSISTANT
What were you doing in that bucket, you silly mallard?
ALAN
ALDA (NARRATION) And it's too attractive for the young chimp. The
pet log should have violated her expectations, as psychologists
say, but she missed it.
DAVID
Bjorklund But you did see earlier when there were the blackbirds
- one being treated like a screwdriver, and one being treated like
a pet, she went with the one being treated like a screwdriver. So
there's a little bit of going-for-the-violation-of-the-expectation,
Noelle. But when push comes to shove, is she has a choice between
an animate object, no matter how it's treated she tends to go towards
that.
ALAN
ALDA (NARRATION) Human 3-year-olds also fail this test. But now
let's see how 9-year-old Grub does, with the identical series of
tests. First hawk-sandpaper… ...against hammer. No problem — but
as with Noelle, this was the only animate element in the trial.
Next, pet-rock against rock-rock.
DAVID
Bjorklund Time.
ALAN
ALDA (NARRATION) Again, no problem. But again this was the only
choice with any animate element to it, in the way it was treated.
Now, animate blackbird treated animately, against screwdriver-blackbird.
It's a tougher choice, but like 3-year-old Noelle he still picks
out the one that's peculiar.
ASSISTANT
Go look.
ALAN
ALDA (NARRATION) Finally the big test. The doubly-attractive mallard
treated animately, against the log treated animately. This is the
one Noelle failed.
ASSISTANT
Look at you. How pretty you are.
ASSISTANT
What a beautiful log you are.
ALAN
ALDA (NARRATION) And unlike the younger Noelle, Grub gets it — as
would a 9-year-old human. All the chimps we've seen in this show
give us a fascinating glimpse into what human and chimp minds share
— and into how, in the last 6 or 7 million years, they've grown
apart.
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