< Return to Video

NOVA scienceNOW : 1 - Mirror Neurons

  • 0:02 - 0:06
    ROBERT KRULWICH: Hello again. Gaze into a
    mirror, and what do you see? Well, I see my
  • 0:06 - 0:13
    face, of course. But in my face I see moods,
    I see shifts of feeling.
  • 0:13 - 0:18
    We humans are really good at reading faces
    and bodies. 'Cause if I can look at you and
  • 0:18 - 0:25
    feel what you're feeling, I can learn from
    you, connect to you, I can love you. Empathy
  • 0:25 - 0:29
    is one of our finer traits, and when it happens
    it happens so easily, perhaps becauseóand
  • 0:29 - 0:35
    this is brand new science, this is just out
    of the labówe may have some special circuitry
  • 0:35 - 0:41
    in our brains that helps us whenever we look
    at each other.
  • 0:41 - 0:48
    Ask yourself, "Why do people get so involved,
    so deeply, deeply involved, with such anguish,
  • 0:51 - 0:55
    such pain, such nail biting tension over football?"
  • 0:55 - 1:00
    COMMENTATOR: The Cleveland Browns are gambling
    on defense.
  • 1:00 - 1:07
    ROBERT KRULWICH: Why are we such suckers for
    sports? And it's not just sports. We can lose
  • 1:11 - 1:18
    it completely at the movies, at video games,
    watching a dance. Is there something about
  • 1:22 - 1:29
    humans, humans particularly, that allows us
    to connect so deeply when we watch other peopleówatch
  • 1:29 - 1:35
    them moving, watch them playing, watch their
    faces?
  • 1:35 - 1:41
    Well, as it happens, scientists have an explanation
    for this strange ability to connect. It's
  • 1:41 - 1:42
    new.
  • 1:41 - 1:44
    DANIEL GLASER: It had never been found on
    a cellular level before.
  • 1:44 - 1:49
    ROBERT KRULWICH: A set of brain cells, found
    on either side of the head, among all the
  • 1:49 - 1:55
    billions of long branching cells in our brain,
    these so-called "mirror neurons," have surprising
  • 1:55 - 1:55
    power.
  • 1:55 - 2:00
    DANIEL GLASER: What we've found is the mechanism
    that underlies something which is absolutely
  • 2:00 - 2:03
    fundamental to the way that we see other people
    in the world.
  • 2:03 - 2:09
    ROBERT KRULWICH: And it began entirely by
    accident, at a laboratory in the lovely old
  • 2:09 - 2:15
    city of Parma, Italy, where a group of brain
    researchers was working with monkeys, and
  • 2:15 - 2:20
    they were testing a neuronóthat's a brain
    cellóthat always fired...made this sound...
  • 2:20 - 2:21
    (NEURON FIRING): Clack, clack, clack.
  • 2:21 - 2:24
    ROBERT KRULWICH: ...whenever the monkey would
    grab for a peanut. So the lab had all these
  • 2:24 - 2:26
    peanuts around, and whenever the monkey made
    its move...
  • 2:26 - 2:27
    (NEURON FIRING): Clack, clack, clack.
  • 2:27 - 2:29
    ROBERT KRULWICH: ...the neuron would fire.
  • 2:29 - 2:35
    Scientists thought, "Now here's a neuron that's
    essential to motion. It's a motor neuron."
  • 2:35 - 2:40
    Then, one day, the monkey was just sitting
    around, not moving at all, just sitting, when
  • 2:40 - 2:46
    a human scientist came into the lab. And when
    that scientist grasped the peanut? Yeah, the
  • 2:46 - 2:47
    monkey's cell fired.
  • 2:47 - 2:53
    Now, the monkey hadn't moved, it was the human
    that had moved, suggesting that this neuron
  • 2:53 - 2:57
    up here couldn't tell the difference between
    seeing something and doing somethingóseeing
  • 2:57 - 3:03
    and doing were the sameóor more intriguingly,
    that for this neuron, watching somebody do
  • 3:03 - 3:05
    something is just like doing it yourself.
  • 3:05 - 3:08
    The head of the lab, Giacomo Rizzolatti, thought,
    "Wow!"
  • 3:08 - 3:12
    GIACOMO RIZZOLATTI (University of Parma):
    The same neurons, one neuron, fired, both
  • 3:12 - 3:17
    when the monkey observed something, and when
    the monkey is doing something. It is almost
  • 3:17 - 3:17
    unbelievable.
  • 3:17 - 3:22
    DANIEL GLASER: It was surprising, because
    this cell, which was involved with motor planning
  • 3:22 - 3:27
    for the monkey, turned out to be interested
    in the movements of other people as well.
  • 3:27 - 3:32
    ROBERT KRULWICH: Some people call them "monkey
    see, monkey do" neurons, but the name that
  • 3:32 - 3:38
    stuck is "mirror neurons," because with them,
    the brain seems to mirror the movements it
  • 3:38 - 3:39
    sees.
  • 3:39 - 3:44
    This accidental discovery got scientists thinking,
    doing more tests, and soon it came pretty
  • 3:44 - 3:50
    clear that this is not just a monkey thing,
    it's a people thing, too.
  • 3:50 - 3:56
    We all know that humans learn by looking and
    copying; that's what infants do.
  • 3:56 - 3:57
    First you look...
  • 3:57 - 3:58
    MOTHER: One, two, three, four.
  • 3:58 - 4:00
    ROBERT KRULWICH: ...then you do.
  • 4:00 - 4:03
    DONNA: Ready? Let's see your feet this way.
  • 4:03 - 4:07
    ROBERT KRULWICH: And once you've watched and
    copied and learned a set of moves, you not
  • 4:07 - 4:14
    only have them in your head, if you see somebody
    else doing it you can share the experience.
  • 4:17 - 4:21
    They know the moves, you know the moves, so
    you can move with them.
  • 4:21 - 4:25
    DANIEL GLASER: If you can use the years of
    training that you, yourself, have doneólearning
  • 4:25 - 4:30
    to crawl, then learning to walk, then learning
    to eatóthis is an incredibly rich set of
  • 4:30 - 4:35
    knowledge that you could apply to the problem
    of actually seeing what's going on.
  • 4:35 - 4:40
    ROBERT KRULWICH: So that's why, when I head
    down the street carrying all these packages,
  • 4:40 - 4:44
    not only do people watch, look how they're
    watching.
  • 4:44 - 4:50
    They feel my predicament because they know
    what it's like to carry heavy packages. They
  • 4:50 - 4:57
    know all about "carrying." So as they watch
    me moving they can feel themselves moving.
  • 4:57 - 5:04
    Their neurons are "mirroring" the action.
  • 5:08 - 5:15
    These neurons may be the brain's way of translating
    what we see so we can relate to the world.
  • 5:15 - 5:21
    DANIEL GLASER: The mirror system is the way
    that you tap into...the way that you harness
  • 5:21 - 5:25
    your own abilities and project them out into
    the world.
  • 5:25 - 5:31
    ROBERT KRULWICH: And people are really good
    at watching and translating what we see. Like,
  • 5:31 - 5:35
    with just thirteen moving dotsóthat's all
    there are hereóyou'll have no trouble recognizing
  • 5:35 - 5:41
    these very ordinary activities. What's more,
    tests have shown that when a person sees a
  • 5:41 - 5:47
    movie like this of his own movement, he'll
    recognize it immediately as his own.
  • 5:47 - 5:54
    And that's why sports fans tense with the
    action, and wince, and leap. 'Cause if you
  • 5:54 - 5:55
    know the game...
  • 5:55 - 5:57
    FOOTBALL FAN 1: Flag! Flag!
  • 5:57 - 5:58
    FOOTBALL FAN 2: No, no, no flag.
  • 5:58 - 6:00
    FOOTBALL FAN: No flag.
  • 6:00 - 6:03
    ROBERT KRULWICH: ...then your neurons are
    firing as if it's you playing, giving whole
  • 6:03 - 6:10
    new meaning to the phrase "armchair quarterback."
    That's why it's so easy to be a sports fan.
  • 6:11 - 6:18
    But there is more, suggests U.C.L.A. professor
    Marco Iacoboni. He thinks mirror neurons tie
  • 6:19 - 6:23
    us, not just to other people's actions, but
    to other people's feelings.
  • 6:23 - 6:27
    MARCO IACOBONI (University of California,
    Los Angeles): So the idea was to try to figure
  • 6:27 - 6:32
    out how the emotional system and this motor
    system are connected together.
  • 6:32 - 6:35
    We're going to go in the scanner and what
    you're going to do is to...
  • 6:35 - 6:38
    ROBERT KRULWICH: To demonstrate, he put me
    into this very powerful f.M.R.I. brain scanner
  • 6:38 - 6:42
    that can peer into the brain while it's working.
  • 6:42 - 6:45
    And he gave me some goggles so he could show
    me pictures when I was in there.
  • 6:45 - 6:48
    MARCO IACOBONI: So you can see here the eyeball
    of Robert.
  • 6:48 - 6:51
    ROBERT KRULWICH: And once he had a good view
    into my brain...
  • 6:51 - 6:52
    MARCO IACOBONI: Nice looking brain.
  • 6:52 - 6:53
    ROBERT KRULWICH: Thank you.
  • 6:53 - 6:57
    MARCO IACOBONI: Robert, you're not supposed
    to talk when we scan you, all right?
  • 6:57 - 6:58
    ROBERT KRULWICH: Sorry.
  • 6:58 - 7:05
    Then he said, "Okay, I'm going to show you
    a bunch of faces. And for each face, I want
  • 7:05 - 7:07
    you to imitate it."
  • 7:07 - 7:14
    So I did that. Then he recorded my brain while
    I moved my facial muscles.
  • 7:14 - 7:17
    MARCO IACOBONI: We're going do, right away,
    another one.
  • 7:17 - 7:18
    ROBERT KRULWICH: Okay.
  • 7:18 - 7:25
    Then he said "Okay, same faces, but this time,
    don't move a muscle, just look." So I looked.
  • 7:28 - 7:29
    When we checked the results...
  • 7:29 - 7:32
    Oh, there's my brain. I've never seen my brain
    before.
  • 7:32 - 7:33
    MARCO IACOBONI: This is your mirror area.
  • 7:33 - 7:39
    ROBERT KRULWICH: Iacoboni says that the part
    of my brain that's working when I make a face,
  • 7:39 - 7:44
    the same part gets busy when I see the face.
  • 7:44 - 7:51
    Plus, when I was looking at these faces, I
    remember feeling extra uncomfortable, kind
  • 7:52 - 7:59
    of bad. But when these faces came on, I felt,
    I don't know, I felt better, almost happy.
  • 7:59 - 8:06
    And, in fact, at that moment I was looking
    at the happy face, my brainóand this is my
  • 8:07 - 8:13
    brain at that instantósee that red area here,
    it shows activity in the "happy" emotional
  • 8:13 - 8:14
    part of my brain.
  • 8:14 - 8:18
    And when I was imitating "happy" faces, look.
    I get an even bigger response.
  • 8:18 - 8:25
    This, says Iacoboni, is a consistent result.
    Mirror neurons, he believes, can send messages
  • 8:25 - 8:32
    to the limbic, or emotional system in our
    brains. So it's possible these neurons help
  • 8:32 - 8:36
    us tune in to each others' feelings. That's
    empathy.
  • 8:36 - 8:40
    MARCO IACOBONI: We strongly believe that that's
    a unifying mechanism that allows people to
  • 8:40 - 8:43
    actually connect at a very simple level.
  • 8:43 - 8:48
    ROBERT KRULWICH: You are saying that there's
    a place in my brain, which...whose job it
  • 8:48 - 8:54
    is to live in other people's minds, live in
    other people's bodies?
  • 8:54 - 8:55
    MARCO IACOBONI: That's right.
  • 8:55 - 8:59
    HELEN HAYES in A FAREWELL TO ARMS: Oh, darling,
    I'm going to die! Don't let me die!
  • 8:59 - 9:01
    GARY COOPER in A FAREWELL TO ARMS: Kat!
  • 9:01 - 9:06
    ROBERT KRULWICH: And great actors instinctively
    know that if they put feeling and drama into
  • 9:06 - 9:07
    their bodies,...
  • 9:07 - 9:12
    HELEN HAYES in A FAREWELL TO ARMS: Hold me
    tight! Don't let me go!
  • 9:12 - 9:14
    ROBERT KRULWICH: ...their faces, we will respond.
  • 9:14 - 9:18
    GARY COOPER in A FAREWELL TO ARMS: You can't
    die. You're too brave to die!
  • 9:18 - 9:23
    DANIEL GLASER: What actors are experts in
    is using their movements to inspire feelings
  • 9:23 - 9:26
    in the people watching. These are the experts
    in the mirror system.
  • 9:26 - 9:30
    V.S. RAMACHANDRAN (University of California,
    San Diego): We are intensely social creatures.
  • 9:30 - 9:34
    We literally read other people's minds. I
    don't mean anything psychic like telepathy,
  • 9:34 - 9:37
    but you can adopt another person's point of
    view.
  • 9:37 - 9:39
    LINDSAY SCHENK (University of California,
    San Diego): When you put it together, what
  • 9:39 - 9:40
    do you think it's going to be?
  • 9:40 - 9:44
    ROBERT KRULWICH: So if mirror neurons help
    us connect emotionally, what about people
  • 9:44 - 9:47
    who have trouble with this? Kids like Christian,
    who has autism?
  • 9:47 - 9:49
    LINDSAY SCHENK: Why do you like LEGOÆs?
  • 9:49 - 9:54
    V.S. RAMACHANDRAN: It's been known for some
    time that children with autism could be quite
  • 9:54 - 9:58
    intelligent, but have a profound deficit in
    social interaction.
  • 9:58 - 10:03
    ROBERT KRULWICH: Christian can speak and read
    and write, but like many kids with autism,
  • 10:03 - 10:07
    he will avoid eye contact, he often misunderstands
    questions.
  • 10:07 - 10:11
    LINDSAY SCHENK: So, Christian, can you tell
    me what you did in school today?
  • 10:11 - 10:12
    CHRISTIAN: Doing well.
  • 10:12 - 10:14
    LINDSAY SCHENK: You're doing well?
  • 10:14 - 10:15
    CHRISTIAN: Mmhmm.
  • 10:15 - 10:20
    ROBERT KRULWICH: Everybody wants to know what
    exactly causes this. So Dr. Ramachandran and
  • 10:20 - 10:23
    his graduate student, Lindsay Schenk, designed
    an experiment...
  • 10:23 - 10:27
    LINDSAY SCHENK: So we're going be reading
    your brainwaves with this cap.
  • 10:27 - 10:33
    ROBERT KRULWICH: They recorded brainwaves
    while the kids opened and closed their hands
  • 10:33 - 10:38
    and while they looked at a movie of somebody
    else's hands. For most people, the brainwave
  • 10:38 - 10:44
    looks the same either way, whether they're
    doing or seeing. But for the kids with autism,
  • 10:44 - 10:50
    the wave changes, suggesting, possibly, that
    autism might have something to do with broken
  • 10:50 - 10:51
    mirror neurons.
  • 10:51 - 10:55
    V.S. RAMACHANDRAN: Their brains may indeed
    be different in that regard, and they may
  • 10:55 - 10:59
    have deficits in their mirror neuron system.
    But we don't know this for sure yet. There
  • 10:59 - 11:01
    needs to be...additional work needs to be
    done using brain imaging.
  • 11:01 - 11:05
    ROBERT KRULWICH: But what we do know, says
    Ramachandran, is that healthy human beings
  • 11:05 - 11:12
    are intensely social. More than our cousins,
    the monkeys, we invent ways to connect. We
  • 11:12 - 11:19
    invent dances, and handshakes, and games to
    play. We eat together. We meet and we talk.
  • 11:26 - 11:26
    We talk a lot.
  • 11:26 - 11:32
    V.S. RAMACHANDRAN: Everybody's interested
    in this question: "What makes humans unique?"
  • 11:32 - 11:36
    What makes us different from the great apes,
    for example? You can say humorówe're the
  • 11:36 - 11:43
    laughing bipedólanguage certainly, okay?
    But another thing is culture. And a lot of
  • 11:44 - 11:48
    culture comes from imitation, watching your
    teachers do something.
  • 11:48 - 11:55
    ROBERT KRULWICH: And here V.S. Ramachandran
    makes a big leap. He has proposed that at
  • 11:55 - 12:01
    a key moment in our evolution, this is his
    guess, our mirror neurons got better. And
  • 12:01 - 12:05
    that made all the difference, he says, because
    once we humans got better at learning from
  • 12:05 - 12:12
    each otherólooking, copying, teachingówe
    could do things the other creatures couldn't.
  • 12:12 - 12:18
    V.S. RAMACHANDRAN: In other words, if you
    are a bear, and suddenly the environment turns
  • 12:18 - 12:24
    cold, you need a few million years to develop
    polar bear type layers of fat and fur.
  • 12:24 - 12:30
    ROBERT KRULWICH: It would take many, many,
    many bear generations to select for furrier
  • 12:30 - 12:32
    bears. But, says Ramachandran...
  • 12:32 - 12:37
    V.S. RAMACHANDRAN: If you're a human, you
    watch your father slaying another bear and
  • 12:37 - 12:42
    putting on a fur coat, you know, skinning
    it, using that as a coat. You watch it, you
  • 12:42 - 12:47
    learn it instantly. Your mirror neurons start
    firing away in your brain, and you've performed
  • 12:47 - 12:53
    the same sequence, complicated sequence. Instead
    of going through millions of years of evolution,
  • 12:53 - 12:55
    you've done it in one generation.
  • 12:55 - 13:00
    ROBERT KRULWICH: And while no one is claiming
    that mirror neurons are the key ingredient
  • 13:00 - 13:05
    that makes us different from other creatures,
    what these neurons do suggest about us seems
  • 13:05 - 13:12
    almost self-evident. You can see it any Sunday
    at a sports bar, that deep in our architecture,
  • 13:12 - 13:16
    down in our cells, we are built to be together.
  • 13:16 - 13:20
    DANIEL GLASER: There'd be very little point
    in having a mirror system if you lived on
  • 13:20 - 13:24
    your own. There'd be a lot of point in having
    a digestive system if you lived on your own.
  • 13:24 - 13:27
    There'd be a good point in having a movement
    system if you lived on your own. There'd be
  • 13:27 - 13:30
    a good point in having a visual system if
    you lived on your own. But there'd be no point
  • 13:30 - 13:36
    in having a mirror system. The mirror system
    is probably the most basic social brain system.
  • 13:36 - 13:40
    It's a brain system which there's no point
    in having if you don't want to interact or
  • 13:40 - 13:41
    relate to other people.
  • 13:41 - 13:45
    ROBERT KRULWICH: But we do like to interact.
    And maybe now, as never before, we will understand
  • 13:45 - 13:46
    why. Okay, now, before we leave this subject,
    we've designed a little mirror neuron exercise.
  • 13:45 - 13:46
    What we're going to do is take a wishbone,
    an ordinary wishbone, the kind you break for
  • 13:46 - 13:46
    good luck, and we're going to take itócome
    onóand we're going to take it for a stroll.
  • 13:46 - 13:47
    And, if your mirror neurons are working properly,
    when you see anything, even a wishbone walking,
  • 13:46 - 13:47
    you know, along, you won't just watch that
    bone, you are going to be that bone.
  • 13:46 - 13:47
    The walking bone was created and designed
    by artist Arthur Ganson, and later in the
  • 13:46 - 13:49
    program we will show you a host of Ganson
    gadgets in glorious motion.
Title:
NOVA scienceNOW : 1 - Mirror Neurons
Description:

more » « less
Video Language:
English
Duration:
13:51

English subtitles

Revisions