ELI5: Explain Like I'm 5

Equilibrium selection

Alright kiddo, today we're going to talk about equilibrium selection, which is a way of figuring out what should happen when two or more people make choices that affect each other.

Picture this: you and your friend want to play a game, but you can't agree on which game to play. You want to play Uno and your friend wants to play Checkers. Hmmm, what do we do? Well, if you think about it, there's no right or wrong answer – it just depends on what you guys decide together.

Now let's say there are a bunch of other kids around, and some of them want to play Uno too, while others want to play Checkers. Suddenly, things get a bit more complicated. How do we figure out what to do?

This is where equilibrium selection comes in. It's like a way to help everyone agree on the same thing.

An equilibrium is like a fancy word for balance. It's when everyone is doing the best they can, given what everyone else is doing. So in our game example, an equilibrium might be when everyone has agreed to play Uno, even if some people wanted to play Checkers at first.

But how do we get to that equilibrium? Well, there are a few ways. One way is to use something called a dominant strategy. This means that each person picks the option that's best for them, no matter what everyone else does. So if you always pick Uno no matter what, and your friend always picks Checkers no matter what, we won't be able to reach an equilibrium. But if we can find a way for both of you to agree on a dominant strategy – like, maybe you both like Uno better than Checkers – then we can reach an equilibrium easily.

Another way to find an equilibrium is through trial and error. You might try to propose different games, and see which one everyone agrees on the most. This can take longer, but it can work too.

Either way, the point is to figure out a way to get everyone on the same page, without anyone feeling left out or unhappy. So the next time you and your friend can't decide what to do, remember that there's always a way to come to an equilibrium!
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