Science & Technology

Scientists Taught Chimps to Play Rock, Paper, Scissors

Primates — other than ourselves, of course — aren't generally known for their ability to play structured games. After all, there's a reason why we call goofing off with no real purpose "monkeying around." But a new study has shown that you actually can teach a chimp to play rock-paper-scissors. And what's more, chimps might be even better than us at certain strategy games.

A Game for the Whole Primate Family

You might not recognize rock-paper-scissors the way these chimps play it. That's mainly because of the way they learned it. See, the purpose behind this study was to figure out if chimpanzees could conceptualize the cyclical pattern: rock-beats-scissors-beats-paper-beats-rock. To teach them the game, the researchers at Japan Monkey Centre first showed the chimps a monitor with a chimp hand in the "paper" position and a chimp hand in the "rock" position. When they pointed out the correct winner, they were rewarded with an apple slice. The apes then learned what happened with rock-versus-scissors, and finally scissors-versus-paper. Completing the circle gave the chimps the most trouble, but after about 300 sessions, most of the chimps had gotten it down pat.

Chimpanzee Ai carrying out a task on the touch screen.

Once they'd learned the game, the chimps turned out to be pretty good at it. Well, about as good as a four-year-old child, anyway. But the big difference between human toddlers learning the game and adult chimpanzees was speed. When a group of kids ages 3–6 were taught the game, it only took them about five sessions to put it all together. And while the chimps were about on par with preschoolers, even slightly older children were able to play the game with a degree of strategy instead of blind luck. So if you ever find yourself on a Planet of the Apes, you might try challenging them to a game instead.

Six sets of stimuli were used. From top to bottom the stimuli were pictures of chimpanzee and human hands, numbered 1, 2, and 3, respectively. From left to right the three stimuli in each set represent paper, rock, and scissors, respectively. In the training phase, chimpanzees were presented with the chimp hand 1 stimuli and the other five sets of stimuli during the generalization tests. Children were exposed to the human hand 1 stimuli in experiment 2.

When Chimps Are Champs

So it seems like humans have got the interspecies Olympics wrapped up, no matter what the game, right? Wrong. Actually, chimpanzees are much better than humans are at remembering a scene exactly, and at memorizing patterns (it's the circular part of rock-paper-scissors that bothers them, not the pattern). Maybe that's how Kanzi the Bonobo is so good at Pac-Man, though he certainly wouldn't stand up to the pros.

But there's one game that chimps actually do best us at. In this simple strategy game, both players are asked to choose either a square on the right or a square on the left. If they both choose the same square, the first player wins, and if they choose different squares, the second player does. Shockingly, the chimpanzees were much better at recognizing their human opponents' patterns. Even more incredible is the apes' ability to immediately memorize visual patterns. Watch the video below and see if you think you could best your hairy cousins.

Related Video: Chimpanzees and Bonobos Use Gestures With the Same Meaning

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Learn about chimpanzees from the world's most famous primatologist in "My Life with the Chimpanzees" by Jane Goodall. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Reuben Westmaas August 14, 2017

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