Narrator: Mark Mitton is a magician who claims he can remove someone's watch while doing a card trick—

Mark Mitton: You want to see a quick trick?

Narrator: —without their feeling a thing.

Mark Mitton: Are you at all interested in seeing some magic? Who's the most psychic among you? Who's the person that can read minds? Little card trick— is that cool?

I want you to name a card. It's going to appear right here. Any card you want. Whatever you want.

Man 1: Ace of spades.

Woman 1: Four.

Man 2: King of hearts.

Man 3: Six.

Man 4: Hearts.

Man 5: Ten of diamonds.

Woman 2: All right.

Mark Mitton: And grab me by the wrist. I want you to name a card. It's going to appear right here, OK?

Woman 2: Just—

Mark Mitton: Yeah, hold them really tight, so there's no way I can get out the cards. It's going to appear in my hand on the count of three.

Man 6: Seven of spades.

Narrator: Look at his right hand.

Mark Mitton: I'm going to do it right now. Really bear down so I can't cheat.

Narrator: And yes— there goes the watch.

Mark Mitton: Seven of spades, right there. Look, look, look, look. Is that good, or what?

Narrator: Amazingly, no one misses the feel of the watch strap on their skin.

Mark Mitton: And inside my hand, look—

Man 2: Five of diamonds.

Mark Mitton: Five of diamonds. Look inside my hand, like this. You see it? Inside my hand, you can see it right there. Oh, shoot. But something very strange happened. Did you see it?

Woman 2: No, what did you do?

Mark Mitton: Look in your hair. I don't know if you can hear— but seriously, there's something. See that?

Woman 2: Oh my god, my watch!

Man 6: Seven of spades.

Narrator: When something more important seems to be happening elsewhere, your brain chooses to ignore some touches.

Mark Mitton: I forgot. We have a gift for you, OK? It's a special gift. Come look.

Woman 3: Oh, my watch!

Man 2: You have my watch.

Man 8: Dude, you're nuts. You're so crazy! Oh, my god, you're so psycho!

Man 9: Oh, [inaudible].

Mark Mitton: Isn't that weird?

Girl: Yeah!

Mark Mitton: How about this?

Woman 4: That's my watch!

Woman 5: You're good.

Narrator: So if we can tune out gentle touches, what about more intense sensations? Can our brains alter how much pain we feel?

Professor Tony Dickinson has devised an experiment using electric shocks. If we're expecting something to hurt, will it feel more painful?

Half the volunteers are given a tablet that they're told will make them feel more pain. Actually, it's just sugar. They feel pain even at low levels because they're expecting the shocks to hurt.

Volunteer 1: Ow.

Narrator: The rest of the volunteers are also given a sugar pill, but they're told it's a painkiller. They're hardly bothered by the low level electric shocks. And even when the dial is cranked right up, the group who think they've taken a painkiller can still cope. The suggestion that the pill will make them feel less pain works.

Volunteer 2: [inaudible]

Narrator: But the volunteers who think they're on a pain booster react very differently.

Volunteer 3: Oh!

Volunteer 4: Stop.

Volunteer 5: Ooh.

Narrator: They're actually feeling a lot more pain.

Volunteer 3: That's a bit of a shock.

Volunteer 6: Ow!

Tony Dickenson: So we showed that expectation had a marked effect on the amount of pain that these two groups felt. So in the group who'd been told they had a painkiller, they could put up with much greater electrical shocks. The other group, where we told them that the pill they'd taken was going to increase the amount of pain that they would feel— in that group, they called a halt very early on in the series of shocks.

Narrator: It's all down to the power of expectation. If you think something's going to hurt, then the chances are—

Volunteer 7: Stop, stop, stop, stop

Narrator: —it will.

Volunteer 8: Ow.