How to win the rock-paper-scissors game

Data and insights are popping up in the oddest places… like on the playground. Or paying the bar tab. Or shotgunning the front seat on your next road trip.

From pavements to school playgrounds, much of the world has relied on the use of the hand game rock-paper-scissors to decide small and large issues of chance. When I was at university, I knew this one girl who had an uncanny ability to win the game almost every time. Theories abounded on how; was she faster? Could she read minds? Did she read our tells like a poker expert? Perhaps none of the above. But it’s a question that’s captured minds across the 'net.

In April of 2014, a group of students at China’s Beijing Academy of Sciences published a revolutionary study on how to win the RPS game almost every time. How? Using data and insights, of course.

The study posits that Rock-Paper-Scissors is a basic study in human decision-making and insights. Here’s how it works.

  • Observe the first round. It’s hard to beat the first round – but that doesn’t really matter so much. Watch everyone’s responses.
  • After the first round, the winner will usually stay with the same play.
  • The loser(s) will usually switch to another play, but in a clockwise direction: rock changes to paper, paper changes to scissors, scissors changes to rock, like in the diagram below:

It’s easy to get confused on the application, so here’s a scenario.

I play a two-player game with my teammate, Jen:

Round 1: Jen plays scissors, I play paper. Jen wins.
Round 2: Jen plays scissors, I switch to scissors. It’s a tie.
Round 3: Jen plays scissors, I switch to paper, so I lose.

If I had put my learning from the study into my strategy, I might do this:

Round 1: Jen plays scissors, I play paper. She wins. I think of the diagram and switch to the clockwise play from Jen’s scissors, which is rock. So…
Round 2: Jen plays scissors again, I switch to rock. I win. I think there’s a good chance she’ll either switch to the next clockwise play or the play I just did (both are rock)…so…
Round 3: Jen switches to rock, I switch to paper. I win two of three.

The fascinating thing is exploring where insights (in the form of game theory and human behaviour) meets decision making and evolutionary dynamics. Way cooler: that a group of students found the pattern and chose to publish on it.

Where will data take you next?