What Do Mirror Neurons Really Do?

What Do Mirror Neurons Really Do?


[♪ INTRO] If you read some of the less-reputable corners
of the internet, you might have heard strange things about
mirror neurons. According to some people, they are why we
have empathy. And ESP. And telepathy. It probably goes without saying that most
of that isn’t true. They definitely don’t give us superpowers. And there is conflicting research about whether
they’re the basis of empathy. Even if they’re not, though, they are still
a very cool part of your brain and probably, they help us learn from other
people. The name mirror neuron comes from the fact
that they fire both when you do something and when you watch
someone doing something, even if you don’t move a muscle. Basically, it’s as if they mirror the neural
activity of the person actually doing the thing. And they were first discovered in macaque
monkeys in the early 90s . The story goes that one day, while a monkey
had thin needle electrodes inserted into individual neurons in their
brain, some of the graduate students… well, they went and took a lunch break. And while one of those graduate students was
eating in front of the monkey, all of a sudden there was neural activity
in the premotor region of the frontal cortex in the monkey’s brain. This region would normally fire if the monkey
was moving— like reaching for food or eating. But those neurons were firing while the monkey
was motionless and just watching someone else do those things. Further research started mapping out exactly
where these neurons were— and they’re remarkably specific. Like, mirror neurons that fire when an experimenter
grabs a piece of food wouldn’t fire if the experimenter used tools
to grab the food instead. But the big question was whether this happened
in humans, too, because these neurons were in regions of the
brain where monkeys and humans differ quite a lot. Of course, your average human study participant
is a little fussier about getting electrodes planted into individual
neurons inside of their brains, so scientists used electro-encephalograms,
or EEGs, to look for mirror neurons instead, as they
record neural activity through the scalp. Researchers had 20 subjects watch an experimenter
demonstrate some motions with their thumb and index finger
and perform the same motions themselves. And turns out some regions of their brains
did act like the monkeys’ mirror neurons — parts of the motor and premotor areas of the
frontal lobe, for example, as well as where the parietal lobe meets the
temporal lobe— an area involved in vision and focusing attention. But knowing that they’re there and where
they are doesn’t tell us why they’re there. Many neuroscientists now think they help us
learn from other people through observation. Take a 2009 study, for example, which looked
at how these parts of the brain are active while people were
being taught how to dance. The researchers used a game similar to Dance
Dance Revolution, and varied whether the participants were taught
the steps using symbols on a screen or a human model in addition
to the symbols. And they found that parts of the mirror neuron
network really tune in to human actions. For example, the superior temporal cortex
was more active while watching a person demonstrate the dance than
the symbolic break down of the steps. But perhaps more to the point, the participants’
performance on a final dancing test was better when they had a human
to watch, which suggests that these regions support
observational learning. Human mirror neurons aren’t exactly the
same as the monkey ones, though. Ours seem to care about the actual movement, while theirs are more strongly tied to the
movement’s meaning. Like, say you grab a water bottle the way
you normally would. And then, you put it down, and grab it with
your hand upside down instead, which makes drinking it a lot harder. It’s basically the same muscle motion either
way, but one serves a meaningful function. In a macaque, watching the meaningless action
might not activate their mirror neurons. But in people, the mirror neuron regions of
the frontal lobe activate regardless of whether the action makes sense. All that matters is the actual hand motion. It’s possible that this helps explain why
humans are so good at learning by imitation— part of our brain is always paying attention
to motions that seem meaningless, just in case we can learn from them. Now, you might be wondering where empathy
comes in to all of this. Well, when you think about it, if part of
your brain activates the same way when you’re observing an action
as when you’re performing it, then it isn’t that far of a stretch to think
that these mirror neurons could be involved in feeling part of what someone else is feeling
simply by seeing them express an emotion. And although this would be very cool if it
were true, the research to date is kind of all over the
place. Like, one study did find that mirror neurons
activate when people empathize with characters in scenes. In one scene, for example, the 18 subjects
had to identify the emotions felt by both a son who was bringing
home a failing report card, and a dad who hasn’t yet seen it, for example. And in addition to identifying the emotions
of both characters in the story, they had to guess what both characters would
be experiencing if they had more information. One of the mirror neuron regions — the inferior
parietal lobe — was active while identifying the emotions
in the story. And scores on a test of empathy were related
to how active that region got when they had to make an inference about the
dad, who was still in the dark. Not all studies show this, though. In fact, many do not. But, then again, most studies in this area
have small sample sizes, so there’s a chance that there are real relationships
between these neurons and empathy that aren’t being
detected. And just to make things more complicated,
these studies are all correlational. They can say that there’s a relationship,
but they can’t directly infer causality. Which means, in the end, we don’t know if
these brain regions are necessary for empathy, or if they just happen to light
up when we’re experiencing it for some unrelated reason. Like with so many things, especially in brain
science, we need more research to figure out what role, if any, mirror neurons actually play in empathy, or if they’re a part of why humans are an
unusually social species. They do, however, seem to be a big part of
how we learn skills through observing others. And that means they’re probably an important
part of how we share skills and behaviors and pass knowledge down from
generation to generation. So no matter what, they are a big deal. They likely are playing a huge role in culture and in all those things that just make us
human. Thanks for watching this episode of SciShow
Psych! And a special thank you to all of the people
who support us on Patreon, because we really couldn’t make this show
if it weren’t for you. If you’d like to learn more about how you
can be one of those excellent people who support this, you can
find out more at Patreon.com/SciShow. [♪ OUTRO]

One Comments

  • Friday We Are Awesome

    September 24, 2019

    Hank Green is everywhere Ö.o

    Reply

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