This is an ABC podcast.

So just take a quick look at your hand.

Unless something is really wrong, you know exactly where to look.

You know it's your own hand you're looking at, and if you wiggle your fingers, you can feel the move.

Your brain is doing a lot of work to enable all of that.

But what if I lost track of what was your hand and what wasn't?

The rubber hand experiment is famous.

It was first done in the 90s and researchers got a bunch of participants to sit at a table

with their left hand resting on top.

A screen was set up to block their view of their hand, and a life-size rubber hand and arm was placed in front of them, in full view.

The experimenters then used paintbrushes to stroke both the rubber hand and the participants hidden real hand at the same time.

Remarkably, people reported that they started to think the rubber hand belonged to them.

Essentially what's happening is this very simple manipulation is creating a discrepancy between what you see and what you feel.

And that's enough essentially to trick the brain into thinking the rubber hand is a part of your body.

This is Mo Costandi. He's a neuroscientist, science writer, and author of BodyM.I., the new science of self-consciousness.

And even weirder, he says, is the fact that subsequent experiments found this rubber hand,

optical illusion, made the real hand behave in bizarre ways.

Its temperature drops by fractions of a degree. It becomes less sensitive to pain. It's as if

the brain has disowned your real hand and it has adopted the rubber hand in its place.

So weird.

Anyways, the original rubber hand study had big implications.

It showed how the brain's bodily awareness was in fact fragile, and it kicked off a whole field of study on the subject.

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