Transcript
[MUSIC PLAYING]
LAWRENCE ROSENBLUM
Hi.
EDIE
Hi.
LAWRENCE
I’m Larry.
EDIE
Hi. Edie.
LAWRENCE
Very nice to meet you, Edie. We’re going to do a little demonstration here called the rubber hand illusion. It’s going to be a little--
NARRATOR
This illusion may look like fairground fun, but it reveals one of the most important new ideas in brain science.
LAWRENCE
Right there. Good, and can you put this hand down right over here, and just curl it up like the rubber hand’s curled up a little bit. All right, now what I’m going to do is try to position the rubber hand so it looks like it’s your own. Okay, could you imagine that being your own hand, kind of?
EDIE
Yeah.
LAWRENCE
What we’re going to do is we’re going to stroke your fingers simultaneously, the rubber finger and your real finger. And hopefully this will convince you that the rubber hand is your own. That your brain will actually adopt this hand.
NARRATOR
In the illusion, simply watching the rubber hand being stroked at the same time as the real hand is enough to trick the brain into adopting it as its own.
LAWRENCE
We like weird. And slowly but surely, you should feel that the hand you’re looking at is actually part of your body.
EDIE
Feels like you’re touching my hand with that one.
LAWRENCE
Right, sort of feels like this is your hand that I’m touching, right?
EDIE
Yeah.
[HITTING RUBBER HAND]
Oh-oh.
[LAUGHTER]
LAWRENCE
You okay?
EDIE
Yeah.
LAWRENCE
Good. Try that at home with your kids, yeah!
The rubber hand illusion is a wonderful example of how multi-sensory perception can influence how we perceive our own body. I mean, that’s how deep multi-sensory perception runs. When you hold your hand out, it’s generally thought that you know it’s there because of the information you’re getting from your muscles and your tendons, and that sort of thing. But what the rubber hand illusion does is show how that can be overridden by visual information.
NARRATOR
The rubber hand illusion shows the powerful connection between what we see and what we feel. But it reveals even more than simply the way our senses are connected. It hints that a fundamental change in the brain is taking place.
MAN
Oh!
[LAUGHTER]
LAWRENCE
Isn’t that strange?
MAN
Yeah, that’s creepy.
LAWRENCE
So, what might be going on in the rubber hand illusion is that the brain is actually changing to accommodate the new rubber hand, going through some sort of structural change that we call ‘neuroplasticity’.
NARRATOR
Neuroplasticity is an exciting new idea that suggests the brain can change in response to experience. And this is what’s taking place in the rubber hand illusion. The brain may be temporarily rewiring itself to adopt the plastic hand as its own.
LAWRENCE
Really feeling like it’s your hand now, huh?
WOMAN
Yes.
LAWRENCE
Is that a little weird?
WOMAN
Yes.
LAWRENCE
Yeah, we like weird in perceptual psychology. There we go.
[HITTING RUBBER HAND]
LAWRENCE
Was that scary?
WOMAN
Yes.
LAWRENCE
Good, we like that.
Brain plasticity is a terrifically exciting sort of phenomenon for perceptual psychology. I think the rubber hand illusion shows that. That the brain can change based on a new experience. And this is important for somebody, say, who doesn’t have vision, to know that they can compensate through plasticity with another sense, and use that to navigate the world.
NARRATOR
This idea of a plastic, flexible brain is so exciting because of the phenomenal possibilities it contains. Not only do our senses work together, but it suggests one could be used to replace another.