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[man] Who's that in the mirror?
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[Hilary Swank] This is known as
the mirror self-recognition test.
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Some versions use a red mark,
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and you pass if you recognize
that it's on your own face.
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Children begin to pass
at around 18 months old,
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which signals a major milestone
in their development.
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Hey.
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The mirror studies are so intriguing,
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because at a very intuitive level,
we relate to the mirror.
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Looking in a mirror, recognizing yourself
has something to do with self-awareness.
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Humans aren't the only animals
that can recognize themselves.
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Chimps were the first
to pass the mirror test.
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Then others followed.
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Dolphins, elephants...
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even magpies.
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And then recently,
the fish study came along.
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I'm not a hundred percent on board
with the fish.
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That fish passing was... controversial.
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And the test has other surprising results.
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Some monkeys don't pass,
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even though they're widely seen
as intelligent animals.
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If you're a dog owner,
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you may have noticed
how your pet reacts to its reflection.
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[barks]
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Research on animal intelligence
over the last few decades
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has sometimes been confounding,
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but it's also given us
profound new insights
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about where we fit into the world.
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To anchor our understanding
of the human mind
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more in where we come from, our ancestry,
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uh, we need to know more about animals.
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So how do other animals think?
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And how does studying
the minds of animals
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reveal what it is... to be human?
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[man] Pretty clever bird, the parrot.
He can actually pronounce words.
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Of course he has no idea
what the words mean.
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-[Ed] I'm a horse, not a guinea pig.
-[laughter]
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[man] Almost everybody
likes to watch animals,
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whose instincts and intelligence
are sometimes remarkable.
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[second man] The lifetime of all mankind
is but a brief moment
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in the long history of this Earth of ours.
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[third man] Not only can we control
many important variables,
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but our subjects are available
when we need them.
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♪ Hey, hey ♪
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♪ Hey ♪
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I think about
what's going on in her little head.
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She's always looking around.
The wheels are always turning.
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He's very smart.
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He's already learned to say
probably about a dozen words or phrases.
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He has a lot of opinions,
and he wants what he wants.
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[man] Elliot's ego
is very easy to damage.
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Whenever Elliot meets other rabbits,
we're always like,
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"Oh, my God, he thinks
he's so much better than them."
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He can be-- I hate
that I'm gonna say this. He can be snappy.
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You know, so many of us who have dogs
or cats or pets have wondered like,
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"What are they thinking? Do they love me?
Like, do they understand this thing?"
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It's such a human thing to do--
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to wonder what's going on
inside another animal's head.
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And we can't just ask them.
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Animals clearly have ways
of communicating with each other.
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Bees do it by dancing.
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-Whales sing.
-[vocalizes]
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-And chimpanzees gesture and scream.
-[screaming]
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But humans have tens of thousands of words
at our disposal,
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which, strung together, can communicate
an infinite number of ideas.
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So seeing if animals
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could communicate with us
in human language
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was one of the first efforts
in animal-intelligence research.
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And this was one of the first experiments
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with a chimp named Viki in the late 1940s.
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Now who am I?
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Papa? Papa?
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You can see it's not going so well.
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It turned out chimp vocal cords
aren't built for speaking.
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But then, in 1966,
a psychologist couple had another idea.
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They brought home
a wild-born baby chimp name Washoe,
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raised her like a human child,
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and tried to teach her
American Sign Language.
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Washoe ultimately learned about 150 signs,
like for these words...
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[man] Toothbrush. Hug.
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Open. Out.
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The linguists had defined language
as symbolic communication.
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Then Washoe came along,
and she was doing symbolic communication.
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She was using hand signals
to refer to certain things.
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Other high-profile
ape language studies followed
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which seemed to show that the human mind
and our ability to communicate
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wasn't so unique after all.
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So the question was,
"Were these apes actually using language?"
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This was a radical question.
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Up until the late 19th century,
the assumption in most Western cultures
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was that human minds
had nothing to do with animals.
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That wasn't the case
in some Eastern religions like Buddhism.
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That view of the universe
looked like this.
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Humans and animals
shared the same essential nature
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and were linked through rebirth.
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But the Christian worldview
looked more like this.
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Humans were superior
because they had souls,
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and animals were ranked below them.
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[Frans] You have mammals, then you go down
to the worms and the molluscs and so on.
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Of course, humans were closest to God,
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'cause the angels and God,
they were just-just above us.
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[Swank] But Charles Darwin
changed all that
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with this first sketch of a tree of life
in his notebook.
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It might look small,
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but this blew up that worldview
with the Theory of Evolution.
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One of the things that Darwin did so well
in the Origin of Species
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was to make vivid an alternative picture,
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a picture in which
it's a tree, not a scale.
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Where all animals
evolved from earlier life forms
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and all life is related,
even if distantly,
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Homo sapiens are right here. That's us.
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Darwin also said that intelligence
must be on this tree, writing,
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"The difference in mind
between man and the higher animals,
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great as it is, certainly is one of degree
and not of kind."
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But the mind is a hard thing
to study scientifically.
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So for much of the 20th century,
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mainstream psychology
measured behavior instead.
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This school of thought
was called behaviorism.
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Behaviorism became a sort of religion.
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At first, I think their goals
were perfectly fine.
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They said, "Let's move away from
internal states
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like feelings and thoughts
and stuff like that
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and just look at behavior."
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But then behaviorism went further,
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arguing that the mind
didn't really matter at all.
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Any sign of intelligence
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was just learned through
a system of rewards and punishments.
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And that's one interpretation
of how apes learned language.
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The psychologist B.F. Skinner
was the high priest of behaviorism.
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[man] His work has been
both applauded and attacked,
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because it details methods
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to shape and control
the behavior of others.
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[Swank] Skinner thought animals
were stimulus-response machines
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and that you could teach them
almost anything
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with the right rewards and punishments,
like teaching pigeons to read.
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[man] He's learned
his different response to each sign
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by being rewarded with food.
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[Swank] Or to play ping-pong.
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Or to fly a World War II missile,
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which actually worked, but was never used.
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Skinner thought humans
learned this way, too,
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even if we were more advanced.
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In a 1977 interview,
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he argued that both human
and animal intelligence
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was just conditioning.
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Of course, human behavior
is extraordinarily different,
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much more complex than animal behavior,
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but the fundamental principles
are probably there.
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[explosion]
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But the linguist, Noam Chomsky,
disagreed with Skinner.
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In an interview that same year,
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Chomsky argued that humans
don't need to be conditioned
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to acquire language.
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We're built for it,
and it's clear from a young age.
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Most parents
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don't give any systematic instruction
of any kind to their children,
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yet the children nevertheless learn.
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In a certain sense, we might go on to say
language isn't even learned.
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And he thought animals
were built for other things.
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When asked whether apes like Washoe
could learn language, he responded,
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"Humans can fly about 30 feet.
That's what they do in the Olympics.
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Is that flying?
The question is totally meaningless."
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After Washoe, researchers
taught sign language to another chimp,
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Nim Chimpsky...
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and reviewed the footage
of previous ape language studies,
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and concluded that chimps
could imitate isolated words,
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but couldn't speak in
spontaneous sentences or with grammar
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the way humans do.
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In the end, Nim Chimpsky's
longest sentence was these 16 words--
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"Give orange me give eat orange
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me eat orange
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give me eat orange give me you."
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Behaviorism fell out of favor.
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Even though we now don't believe so much
anymore that they have language,
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still, they opened up
that whole field of animal cognition
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by showing that apes could do
much more than we thought.
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Today, thanks to Darwin,
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scientists agree that human intelligence
evolved from earlier primates
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with the first big split
around seven million years ago
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and another around 200,000 years ago.
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That's when Homo sapiens appeared.
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Then, in an evolutionary blink of an eye,
humans developed bigger brains,
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complex languages, cultures,
technologies and civilizations
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and spread out around the globe.
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One theory about why
the human brain is exceptional
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is that it just has more neurons.
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The human brain
has roughly 100 billion of them.
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That's over three times more
than a chimpanzee
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and over a thousand times more
than a mouse.
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But recently, a study found that elephants
have close to 260 billion neurons,
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almost three times more than us.
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Scientists have tried to figure out if
the kind of neurons we have are special.
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They don't look special.
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This is so true
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that if you just look at a slide
of a human brain or a mouse brain,
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and you showed a neuron from that slide
to a neuroscientist,
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they'd be really hard-pressed to tell you
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whether that came from a human brain
or from a mouse brain.
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But not all neurons
have the same function.
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Human brains
seem to have particular neurons
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that activate
when we learn from others' behavior.
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They're called mirror neurons.
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But scientists have found similar neurons
in the brains of other primates.
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And a study discovered them
in swamp sparrows, too.
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[chirping]
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They activated when the birds
mimicked the songs of other birds.
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And so we haven't found
the special human neuron yet.
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00:10:27,710 --> 00:10:31,839
And there's a hundred billion neurons,
so there's still a lot to-to search.
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Humans rank the highest
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on the standard calculation
of brain-to-body ratio.
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Other animals we perceive as intelligent
rank highly, too.
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And bigger-brained animals
also tend to have longer lives.
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Often when we're thinking about
intelligence in other animals,
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we tend to focus on
the cognitive capacities
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that we're super proud of in humans.
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Like being socially smart,
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because we develop the ability to live in
complicated social structures.
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But chimps do too on a smaller scale
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which requires the intelligence
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00:11:04,080 --> 00:11:07,541
to make careful judgments
about the feelings of others.
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[Frans] Can I predict the behavior
of somebody else?
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Can I challenge this individual?
Will I have backing if I do that?
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How do I reconcile
and with whom do I reconcile after fights?
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They have to make
complex decisions very often.
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[Swank] Researchers think chimps
experience empathy
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because they have yawn contagion.
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A 2009 study
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discovered that chimps will yawn
when shown a cartoon chimp yawning.
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We used to believe we were unique
in how we use tools to solve problems.
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We encounter problems
that we didn't know would be there, right?
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Because the universe
is a little random, it's hard to predict,
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and I think
one definition of intelligence
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is can that animal solve that problem
that it encounters
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to achieve whatever goal, uh, it wants.
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But in the 1960s,
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Jane Goodall discovered
widespread tool use among chimpanzees,
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and then researchers discovered
something surprising.
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Birds could do this, too.
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00:12:01,971 --> 00:12:05,641
[Frans] For example, New Caledonian crows
are very good tool users.
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We know that now. They even make tools.
They modify them.
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They can all do sequences of tools.
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[Swank] While other animals
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may solve problems
as they come across them,
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humans thought we were at least special
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in that we learn from our memories
and can plan for future problems.
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We used to think of animals,
they're captive of the present.
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We humans are different
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because we tend to think
back in time to specific events.
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We can think forward,
we can make plans for tomorrow
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or even much further away,
and that makes us different.
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But research on the Clark's Nutcracker,
another member of the crow family,
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estimates they can hide
up to 30,000 seeds in the fall
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in 6,000 different locations,
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and then find them again
months later in the spring.
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And I don't even know where
my car is being parked,
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so I think it's pretty impressive
what they do.
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But humans don't just
plan for their own future.
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We plan for the future of our species.
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We build schools, libraries, and museums.
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We have culture.
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[Bobby] Culture is this idea
of shared responsibility for our children.
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And I think that model can be found
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in rudimentary versions
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of animals taking care of their children.
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[Swank] In Côte d'Ivoire,
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a study of three genetically related
groups of chimpanzees
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found that each group
used different types of tools
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to crack open the same African walnuts,
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evidence that each group
taught their offspring differently.
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And whales have culture, too.
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[whale vocalizes]
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This is a hit humpback whale song.
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In 2009, only this group of whales
was singing it.
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Then in 2010,
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they encountered other whale groups
at a communal feeding spot,
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and one of those other groups
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abandoned their own song
and returned home singing this new tune.
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They call this a cultural revolution.
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Discoveries like this
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disrupted our understanding
of how intelligence evolved.
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Birds and whales
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aren't as closely related to humans
as other primates.
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00:14:10,015 --> 00:14:12,184
Whales and humans, both mammals,
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share an ancestor
around a hundred million years ago,
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and our last common ancestor
with the crow family?
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300 million years ago
before the dinosaurs.
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We're kind of converging on
the same abilities,
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not because we're closely related,
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but because we've had
similar problems we've faced,
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and we've come up with
the same cognitive structures.
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This happened with physical traits
all over the animal world.
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Unrelated species independently developed
similar traits to fit their needs,
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like wings, dorsal fins, and venom.
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And this happened to the mind, too.
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Which is why animals
all over the evolutionary tree
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may have a sense of self-awareness.
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Except it's hard to tell with the fish.
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One reason it might have tried
to scrape off the red mark
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is because it could feel it
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when researchers
pricked its scale with ink,
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not because it recognized itself.
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And the mirror test has other limitations.
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Part of the problem, uh, is that
what the test that I gave you
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is a very visual test,
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and it might be that many animals
don't use vision
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the way we use vision to recognize
a sentient other human beings.
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Which highlights a fundamental flaw
in how we've studied the minds of animals.
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In a way, many of our tests
have been like a mirror,
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looking for human qualities,
using human measures
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based on a human perception of the world.
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This is what dogs' vision looks like
compared to humans'.
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Dogs are red-green color-blind,
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and their vision is between
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four and eight times
less precise than humans'.
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But they navigate their world
with their sense of smell,
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which is 10,000 times stronger
than humans'.
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So a researcher designed a test
with canisters of urine
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to see if dogs
could recognize their own scent
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from one mixed with other scents.
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They lingered on the mixed scents
longer than their own,
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indicating that dogs may be self-aware,
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but mainly through smell instead of sight.
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That may also explain why in 2011,
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researchers found that elephants,
a smart animal by many standards,
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failed a simple tool test
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to use sticks to get food
just out of reach.
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In order to understand the elephant,
we need to understand, for example,
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the elephant has
a hundred times better smell than the dog.
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00:16:32,741 --> 00:16:35,577
But then the researchers
modified the test.
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Instead of leaving out sticks,
they left out a box and tire
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to see if the elephants
would stand on them to reach the food.
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And the elephants passed.
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00:16:45,921 --> 00:16:47,631
And the reason is, we think,
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because for an elephant
to pick up a stick...
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it shuts off its smelling organ.
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00:16:52,720 --> 00:16:54,722
And so you need to understand
the elephant
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and understand a trunk
is not the same as a hand.
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It has very different functions.
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00:16:59,977 --> 00:17:03,022
Every animal has its own way
of looking at the world,
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its own perceptual capacities.
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00:17:05,733 --> 00:17:09,403
Some animals hear things and see things
that we don't notice.
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00:17:10,863 --> 00:17:14,283
Take bats, for example,
a species that evolved the ability
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00:17:14,366 --> 00:17:17,369
to sense its surroundings
through echolocation.
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00:17:17,453 --> 00:17:20,789
This means they navigate
by making high-pitched sounds,
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mostly imperceptible to human ears,
that bounce off nearby objects.
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00:17:25,836 --> 00:17:29,381
And salmon can use
the Earth's magnetic field like a compass
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00:17:29,465 --> 00:17:32,384
to navigate across
thousands of miles of open ocean
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00:17:32,468 --> 00:17:34,470
back to their spawning grounds.
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00:17:34,553 --> 00:17:36,305
The fact that we can't do these things
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might make us seem pretty dumb
to a bat or a salmon.
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We're just missing a lot of the stuff
that animals do
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that's incredibly smart
and incredibly clever,
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because we're using human intelligence
as the standard.
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And the more we expand
our idea of intelligence
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to include more animals,
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the more we protect them.
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00:17:55,616 --> 00:17:59,787
The Spanish parliament passed a resolution
to grant rights to great apes
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00:17:59,870 --> 00:18:03,540
to protect them from captivity
or experimentation.
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00:18:03,624 --> 00:18:05,918
A similar case is being made in the U.S.
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00:18:06,001 --> 00:18:08,087
for the legal rights of the first elephant
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00:18:08,170 --> 00:18:10,756
that passed
the mirror self-recognition test.
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00:18:11,507 --> 00:18:14,510
And the Indian government
banned dolphin shows
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because of the mounting evidence that
dolphins are a highly intelligent species.
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We need to anchor our own existence,
so to speak, in nature.
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00:18:24,144 --> 00:18:27,731
We have a tendency to set ourselves apart.
We are separate.
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We are not.
We are completely intertwined with it.
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So we cannot handle nature any way we want
because we have to be careful.
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00:18:34,780 --> 00:18:36,156
Up until recently,
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00:18:36,240 --> 00:18:40,077
most research has focused on animals
that remind us of ourselves.
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And we're just starting
to look beyond them.
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[Bobby] Any of those ways
you think about the octopus,
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it's probably as alien to the human
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as any other animal on the planet.
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[Swank] Octopuses or octopi--
both are correct--
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are part of the cephalopod group
and show typical signs of intelligence.
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Like humans and other primates and birds,
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they use tools like this coconut shell
for protection,
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00:19:10,065 --> 00:19:13,152
and even carry tools with them
for future use,
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00:19:13,235 --> 00:19:16,530
meaning they are planners
like the Clark's Nutcracker.
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00:19:16,613 --> 00:19:19,074
They recognize individual people,
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00:19:19,158 --> 00:19:23,162
and they take an interest in new things,
like this camera.
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00:19:23,245 --> 00:19:27,207
If you bring an unfamiliar object
to most wild animals,
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00:19:27,291 --> 00:19:30,002
they're either scared of it
or they want nothing to do with it,
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00:19:30,085 --> 00:19:32,921
whereas an octopus
often regards a piece of plastic,
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00:19:33,005 --> 00:19:36,967
a brightly colored object of some sort,
as very interesting.
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00:19:38,218 --> 00:19:41,597
Octopuses and their cephalopod relatives,
cuttlefish,
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00:19:41,680 --> 00:19:44,391
can also totally transform
the color of their skin
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00:19:44,474 --> 00:19:45,893
in milliseconds,
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00:19:45,976 --> 00:19:46,935
something scientists
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00:19:47,019 --> 00:19:50,189
traditionally haven't considered
a sign of intelligence.
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Perhaps because humans can't do it.
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00:19:52,691 --> 00:19:54,860
That's when you know
they're gonna take over the world.
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00:19:54,943 --> 00:19:56,570
They have eight arms and can do this.
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00:19:56,653 --> 00:19:59,781
It's obviously something terrible
between us and octopus
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00:19:59,865 --> 00:20:01,533
is gonna have to happen at some point.
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00:20:01,617 --> 00:20:03,452
[chuckles]
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00:20:03,535 --> 00:20:04,494
But octopuses
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00:20:04,578 --> 00:20:07,497
defy the classic correlations
with intelligence.
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00:20:07,581 --> 00:20:10,375
They live short lives, roughly two years,
400
00:20:10,459 --> 00:20:13,837
and they tend to live alone,
not in social groups.
401
00:20:13,921 --> 00:20:17,090
And it's hard to even plot
their brain-to-body ratios
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00:20:17,174 --> 00:20:20,510
because their brain and body
are hard to distinguish.
403
00:20:20,594 --> 00:20:23,388
Of their roughly 500 million neurons,
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00:20:23,472 --> 00:20:25,891
2/3 are spread throughout their tentacles.
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00:20:25,974 --> 00:20:29,478
That could be because they are
further from humans than other primates,
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00:20:29,561 --> 00:20:33,315
other mammals,
and even birds on the evolutionary tree.
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00:20:33,398 --> 00:20:36,151
Our closest ancestor wasn't smart at all.
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00:20:36,235 --> 00:20:40,155
It was something like a worm
living 700 million years ago.
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00:20:40,239 --> 00:20:42,574
[Peter] For most of the time
animals have been evolving,
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00:20:42,658 --> 00:20:46,578
we've been on a separate path from them,
been on an independent track.
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00:20:46,662 --> 00:20:48,622
[Swank] But many scientists
believe octopuses
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00:20:48,705 --> 00:20:51,875
still found their way to an intelligence
we can recognize,
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00:20:51,959 --> 00:20:56,088
which means the possibility
of thinking-and-feeling animals
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00:20:56,171 --> 00:20:58,590
is everywhere
among the millions of species
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00:20:58,674 --> 00:21:00,300
sharing the world with us.
416
00:21:00,384 --> 00:21:04,471
We'd like to understand
what kind of place the universe is.
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00:21:04,554 --> 00:21:07,057
One very important aspect
of that question
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00:21:07,140 --> 00:21:10,602
is which parts of the universe
have experiences
419
00:21:10,686 --> 00:21:13,146
and have thoughts
and-and have minds?
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00:21:13,230 --> 00:21:16,191
I mean, is it just us? Is it everything?
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00:21:16,275 --> 00:21:18,068
Is it just some animals?
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00:21:18,151 --> 00:21:21,571
There's just a kind of importance
inherently to a question of that sort
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00:21:21,655 --> 00:21:24,700
if we want to understand
what kind of world we live in.
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[closing music playing]