# How to Win Rock-Paper-Scissors (with Game Theory)

Rock-paper-scissors seems to be a game of equal chances. Play the game randomly and you should win a third of the time. However, being humans with odd psychology, that’s not how we play at all. In fact, knowing how we really play can help you win RPS all the time. With statistics and game theory no less.

Dr. Hannah Fry explains in a recent Numberphile video how we can use human psychology and a bit of game theory to our advantage:

Based on the statistical trends that came out of those 360 students playing 300 rounds of RPS, a winning hand comes down to taking advantage of two psychological quirks. First, because players who win a round of RPS tend to repeat their winning choice, if you lose, you should change to the selection that didn’t get beaten. For example, if a player beats you with rock, you should chose paper in the next round.

The next tip is where game theory comes in. If you’ve just won, the loser might assume that you are going to repeat your choice (as the statistics support). So they will switch to the selection that wasn’t beaten. In response to that bit of knowledge, winners should play what the loser just played when they lost to have the best chance of beating them. It’s complicated but effective, and Dr. Fry explains it beautifully.

Or you could just be a robot that moves so quickly it can first sense your choice and then choose the winning selection before a human brain can process it.

IMAGES: Numberphile

1. what? says:

Uhhh, great. So if you are both following this advice and you’re the one who lost the first fIrst round, you will also lose every future round because you are BOTH going “backwards”. Sounds like fun.

2. Jon Fong says:

https://itunes.apple.com/us/app/rock-paper-wager!/id910432163?mt=8

nice.  The app above lets you use this strategy and talk trash when you win.  ðŸ™‚

3. Kevie says:

This is what I do. ðŸ™‚

4. A smart red head with an accent… Good God! What have you done!?

• Steve says:

Don’t all people have accents?

5. JÃ¼rgÃ«n says:

She is so beautiful! *.*

6. TK says:

This is a rule for kindergarten kids????
If the winner is smart, They change according to the opponents pattern, and if you’re playing rock paper scissors fast, everyone gets to rely on one overall pattern whether or not they’re trying to come up with something different