How To Always Win Rock, Paper, Scissors

4 min read
Game Strategy

It happens all the time. There is some type of decision to be made or dispute to be settled. Someone will inevitably say, “Let’s do rock paper scissors.” Others tend to agree. It just requires your hands and yields a quick outcome. So let’s do it, right?

You better believe it. This exercise is so popular that you can amuse yourself for hours watching YouTube videos on it, and there was once a World Rock Paper Scissors Society that held tournaments in Las Vegas, one of which was televised on ESPN.

Most people assume the outcome is total, random, blind luck. But there is actually some psychology behind it, which you can use to come out the victor most of the time. Let’s dive in and find out how.

Ground rules

Rock Paper Scissors

Before we begin, let’s not make the assumption that every human has ever made with this venture – that everyone knows how to play. It’s as if everyone believes that as soon as a baby is born, it immediately begins playing rock paper scissors with the other newborns in the maternity ward, no explanation needed. But there may be some novices who haven’t had the game explained to them, so let’s start there.

Each player simultaneously forms one of three shapes with an outstretched hand. These shapes are “rock” (a closed fist), “paper” (a flat hand), and “scissors” (a fist with the index finger and middle finger extended, forming a V). A simultaneous, zero-sum game, it has only two possible outcomes: a draw, or a win for one player and a loss for the other.

A player who decides to play rock will beat another player who has chosen scissors (“rock crushes scissors”), but will lose to one who has played paper (“paper covers rock”); a play of paper will lose to a play of scissors (“scissors cuts paper”). If both players choose the same shape, the game is tied and is usually immediately replayed to break the tie.


Win Game

According to experts, there’s a way to game the game…at its own game.

What’s the catch? Graham Walker, Director of Management of the World RPS Society, gave Mental Floss a few beginners’ tips. For one, males tend to choose Rock on their first throw. So if you’re up against a guy, scissors might be your best bet for a victory. Walker also advises players to avoid delivering the same throw twice in a row (it makes your next move predictable) and try to think one step ahead of your partner. For example, it’s likely that your opponent will deliver the throw that beat her last one. So if she played Paper, beat her next Scissors throw by playing Rock, instead.

If you don’t want to leave it to chance, try game theory. Zhejiang University in China published the first large-scale study of RPS in 2014 using the technique. Their results? Players tend to follow a fairly predictable psychological pattern.

Strategy Game

Although there’s no way to game the first round (it’s a one-third chance your opponent will pick one of the three options), you can predict what choice she’ll make after that. If your opponent wins, it’s likely she’ll choose the same play. But if she loses, she will switch her strategy in a clockwise direction – so rock changes to paper, paper to scissors, and scissors to rock.

Researchers based their conclusions off of a game theory called “the Nash equilibrium,” which predicts that people will choose each of the three options equally over time.

Let’s look at a scenario. You can’t really game the first round. But after that, if a player wins, he will usually stick with the same play. If a player loses, he will usually switch actions in “a clockwise direction”: rock changes to paper, paper to scissors, scissors to rock.

Always Win

Say I am playing three rounds of rock-paper-scissors with my friend Bob.

  • Round 1: Bob plays paper, I play rock. He wins.
  • Round 2: Bob plays paper, I switch to paper. We draw.
  • Round 3: Bob plays scissors, I switch to scissors. Another draw! I lose.

But if I had kept the probabilities from this Zhejiang University study in mind, I could have changed my gameplay like so:

  • Round 1: Bob plays paper, I play rock. He wins.
  • Round 2: Bob plays paper, I switch to scissors. I win.
  • Round 3: Bob switches to scissors, I switch to rock. I win again!

Now that you know a little more, you can emerge as the king or queen of your inner circle when it comes to playing rock paper scissors.