WEBVTT
Kind: captions
Language: en

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- Today we're talking
about trusting your gut.

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A lot of times your gut's
a pretty reliable source.

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If I'm walking through the woods and I see

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a pack of wolves, my gut's gonna be like,

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"Hey, run," and I would do that.

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But should you always stick
with your gut instinct?

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- No!

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- What?

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(funky music)

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To illustrate this point,
we're going to look at

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the Monty Hall Problem.

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Here's how it works.

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You're on a game show.
You've got three doors.

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Behind one, a great prize.

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Let's say it's a car,
like a really cool car.

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Behind the other two, sheep.

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Oh what, you're gonna be one of

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those people who's all like,

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"Oh, a sheep's a good prize, anyway!"

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Well, fine, then it's a dead sheep.

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Oh God, that's upsetting.

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Fine, it's a live sheep. Undo!

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So you've gotta pick one
out of the three doors.

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And we hit the streets
with a tiny game show to

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present the people with that exact choice.

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- Tiny Tiny Game Show!

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- Tiny Tiny Game Show.

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- It's so tiny.

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- Whoa!

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- Behind one of these wonderful
doors is a brand new car!

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- Whoa!

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- Whoo!

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- What kind of car is it?

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- Well, you're gonna find out, aren't you?

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- Okay, okay.

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Behind two of the doors...

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is a sheep!

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- What am I gonna do with a sheep?

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- I dunno.

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- I mean, in the right market,

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that could be worth
the same thing, though.

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- Yeah, well, you know.

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- You don't want a sheep.

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- You don't want a sheep!

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- These sheep are sick.

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- So what I need you to
do is just pick a door.

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- I highly recommend door number one.

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Don't you dare!

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But also door number two's great.

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- I'm gonna go with door number one.

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- Number three.

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- Number one.

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- I think we're gonna go with number two.

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- Three.

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- You just gave us the "no,
don't pick three" look.

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- What are you talking about?

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- Three.

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- Three.

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- Three.

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- I'm gonna pick door number two.

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- Number three.

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- So let's look at the
odds of you winning.

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No matter which door you
choose from the start,

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you have a one in three chance of winning

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and a two in three chance of losing.

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Each door on its own offers
the same probability.

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So, you've picked your door
and crossed your fingers

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when suddenly, the game show host opens up

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one of the doors you haven't picked

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to reveal that one of
the sheep is behind it.

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And he gives you the option
to switch your choice.

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I'm gonna reveal to you...

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- Oh my gosh.

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- That behind door number three...

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- That's a sheep.

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- [Man] Sheep.
- [Host] ...is a sheep.

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- There's a dead sheep.

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- He fainted.

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- Oh!

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- That's what I'm talking about.

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- So knowing that, do you wanna
stick with door number three

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or switch to door number two?

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Should you switch?

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Even if it feels like you're
betraying your gut instinct?

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Yeah! You should switch.

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Why?

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Well, what's important to
note is that if you combine

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the probability of two doors, you'd have

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a two in three chance of winning

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and a one in three chance of losing.

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So because the probabilities
have stayed the same,

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that door you picked initially
had a one in three chance

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of harboring a sweet new
ride, while the other two

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combined had a two in three chance.

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But now that one of
those two unpicked doors

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has been eliminated, that remaining door

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still has that same two in three chance.

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So by switching, you're
twice as likely to win.

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Does that make sense?

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Here, watch how better off
people fare when they switch.

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- I wanna pick number two.

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- You're switching to door number two?

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- I'm switching to door number two.

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- See what happens.

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You're gonna switch to two?

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- You won the brand new car!

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- Whoa!

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- Whoa!

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- It's a car!

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- Whoa!

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- Brand new!

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You won the brand new car!

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- A brand new car!

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- Is it the same sheep?

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- No, it's a different sheep.

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- [Host] And here's a supercut

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of all the losers who didn't switch.

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Let's delight in their misery.

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- I think I'm gonna stick to two.

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(sad music)

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- You're gonna go with your gut?

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- You're sticking with door number three?

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(sheep bleat)

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- Aww, it's a sheep!

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- Aww, it's a sheep.

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- Son of a biscuit!

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- Aww!

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- Oh no!

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- Aww, you got a sheep!

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(sheep bleat)

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- Aww!

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- You got a sheep!

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- When you first choose, it's
only one third of a chance.

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So you actually have a better chance

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when you select a new door.

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- See, that lady gets it.

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Now if it still doesn't make sense to you,

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let's blow the whole thing up and say

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that you were presented with 50 doors.

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You pick one.

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The host then opens 48 doors and

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gives you the chance to switch.

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Are you gonna stick with that
one random door you picked

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or switch to the one door
that the host didn't open?

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Makes a little more sense? Kinda, yeah?

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So, the next time you find yourself

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in one of those classic three-door
scenarios, breathe easy.

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You've got this.

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And that's some cool science for ya.

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- It's cool. It's math, but I think--

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- Ah, you're right. Well...

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- It's fine.

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- It's still a subject in school.

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(both make random noises)