Chimps Understand Rock-Paper-Scissors as Well as Preschoolers

By Elizabeth Preston | August 11, 2017 1:32 pm

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Rock smashes scissors. Scissors cut paper. Paper covers rock. The rules behind the favorite game of schoolyard kids and adults deciding who takes out the trash are pretty simple. But they also represent a kind of logic problem. Four-year-olds can learn the rules, and so can chimpanzees—but the differences in how kids and apes become proficient reveal a little about how their minds work.

The relationship between the three items in rock-paper-scissors is circular. There isn’t a straightforward hierarchy among them. Animals in the wild can benefit from understanding linear hierarchies, such as the order of dominance in a group, or who can fit inside whose mouth. But earlier studies have shown that some animals, such as monkeys, rats and pigeons, can also learn circular relationships.

At the Primate Research Institute at Kyoto University in Japan, scientists attempted to teach seven adult chimpanzees the basics of rock-paper-scissors. In daily training sessions, the apes sat in front of a touch screen and looked at pictures of chimp hands making “rock,” “paper” or “scissors” gestures. First the apes saw only paper paired with rock; they were rewarded with a bite of apple each time they selected paper, but heard a buzzer if they touched rock. Once the apes had mastered that task, they started seeing a new pair of images: rock and scissors. Again, they were rewarded if they chose the right answer.

Next they saw the third pair of images: scissors and paper. This is the relationship that completes the circle, and it took the chimps a lot longer to get the knack of it. Two animals never learned the task at all. The other five, when they’d finally grasped the rules of the game, were tested on photos of other hands in random pairings.

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The researchers used a similar process to teach rock-paper-scissors to 38 kids in China, ranging from almost 3 years old to almost 6. Instead of apple chunks, the kids got to see a cute picture of baby chimpanzees when they chose the right answer. As a reward for participating in the experiments, they got stickers.

After the kids had learned the rules, they were also tested on random pairs of hands. Kids older than about 50 months performed better than they would have by guessing. In other words, children of about 4 can grasp the rules of rock-paper-scissors as well as a chimpanzee.

But the learning process didn’t look the same for human and non-human apes. Chimps found it challenging to learn the third relationship—the one that completes the circle—while it didn’t give kids any extra trouble. And when kids got the wrong answer in a training session, like picking rock over paper, they switched answers right away. Chimps needed more tries to correct themselves. The authors think this might be because children can control their impulses better than chimps. (If there’d been candy on the line, though, it might have been a different story.)


Images: from Gao et al.

CATEGORIZED UNDER: apes, brains, education, top posts
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  • Birdfish

    THERE IS BIAS IN THIS STORY!
    YES BIAS!!!!!

    LOOK AT THE PICTURES.
    WHY DO THE KIDS HAVE HAVE THE white COLOR?
    THERE SHOULD BE SOME SETS OF HANDS BLACK!!!!!!!

    IT SHOWS RACISMS IN THE ARTICLE TO HAVE white HANDS UNDER THE BLACK MONKEY HANDS.
    THIS IS VERY HATEFUL.
    PLEASE CHANGE THIS.
    YOU CAN HAVE ONE white SET OF HANDS BUT THERE SHOULD BE SOME BLACK SETS ALSO.

    NOTE: I HAVE A VERY HATEFUL CYBER STALKER. HE CAN EVEN POST WITH MY SAME NAME! HE IS HATEFUL AND RACIST. PLEASE IGNORE HIS HATEFUL MOCKINGS IF HE SHOWS UP.

  • Birdfish

    YES THERE WERE DELETIONS BECAUSE FAKE BIRDFISH IS VERY HATEFUL
    WE NEED TO UNDERSTAND THAT RACISMS IS EVERYWHERE
    WE MUST FIGHT IT
    AND SHOW SOME BLACK HANDS NOT white HANDS IN THE MONKEY PICTURE

    NOTE: I HAVE A HATEFUL CYBER STALKER. HE CAN EVEN POST WITH MY SAME NAME. PLEASE IGNORE HIS HATEFUL MOCKINGS AND DO NOT LISTEN TO HIM TALK ABOUT COCO OR RACIST THINGS

    • SISTER X

      BUT TRUE THAT KOKO THE GORILLA DOES HAVE A HIGHER IQ THAN MOST BLACK FOLKS

      MY IQ IS ABOUT 46 BUT THAT IS GOOD ENOUGH TO GET FREE WELFARE AFTER GETTING FAT!!!!!!!
      https://uploads.disquscdn.com/images/f5d0b08e64c10e6315db8954b3f192c6c4732251315cc05b679de38b491d6c97.jpg

      • Birdfish

        THIS IS VERY HATEFUL
        NO THAT MONKEY DOES NOT HAVE A HIGHER IQ THAN BLACK FOLKS
        I DONT GET WELFARES I GET PROGRAMS
        I AM NOT FAT I AM HEAVY SET

        • SISTER X

          WELL OK IT IS TRUE

          KOKO IS SMARTER THAN TOBY

          KOKO HAS NEVER BEEN SHOT AT, DOES NOT HAVE A FELONY RECORD OR A LINK CARD AND KNOWS WHO HER FATHER IS ALSO

          • Birdfish

            THIS IS A HATEFUL LIE
            THE MONKEY IS VERY STUPID AND DOES NOT HAVE SMARTS
            NO

            I HAVE PAINS AND SHORT WINDS AND FULL OF WATER
            THEY DID NOT KEEP ME IN THE HOSPITAL BUT SENT ME HOME
            I WAS THERE ALL DAY!!!!!!!!!!!!!!!!!!!!

            I NEED THAT AMBULANCE

          • SISTER X

            BUT TRUE THAT MONKEY DID NOT GO TO JAIL LIKE ME OR DO HARD TIME IN STATESVILLE

            THAT MONKEY STAYED IN SCHOOL AND DOES THE WORKINGS!!!!

            I BROKE THE LAW AND THEN STAYED IN MY FREE APARTMENT TO GET FATTER!!!!

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Inkfish

Like the wily and many-armed cephalopod, Inkfish reaches into the far corners of science news and brings you back surprises (and the occasional sea creature). The ink is virtual but the research is real.

About Elizabeth Preston

Elizabeth Preston is a science writer whose articles have appeared in publications including Slate, Nautilus, and National Geographic. She's also the former editor of the children's science magazine Muse, where she still writes in the voice of a know-it-all bovine. She lives in Massachusetts. Read more and see her other writing here.

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