Chimps Learn Scissors Beats Paper

even though they don’t ever use scissors!  Pretty good, eh?


Chimpanzees learn rock-paper-scissors

New study shows that chimps’ ability to learn simple circular relationships is on a par with that of 4-year-old children

Chimpanzees of all ages and all sexes can learn the simple circular relationship between the three different hand signals used in the well-known game rock-paper-scissors. Even though it might take them longer, they are indeed able to learn the game as well as a young child. Jie Gao of Kyoto University in Japan and Peking University in China is lead author of a study in the journal Primates, which is the official journal of the Japan Monkey Centre, and is published by Springer. The research compares the ability of chimpanzees and children to learn the rock-paper-scissors game.

Gao’s research team wanted to find out whether chimpanzees (Pan troglodytes) can grasp extended patterns. They used the rock-paper-scissors game, a popular children’s game in which the hand signal for “paper” always beats “rock,” while “rock” trumps “scissors,” and “scissors” defeats “paper.” The relationship between the signals are non-linear and must be understood within the context of how the pairs are grouped. Learning such transverse patterns requires enhanced mental capacity and it is useful when forming complex relationship networks, solving problems, or updating what you already know about a subject.

Seven chimpanzees of different ages and sexes living in the Primate Research Institute at Kyoto University were part of the experiment. They sat in a booth housing a computer-based touchscreen and were trained to choose the stronger of two options (based on the rules of the game) they saw on screen. They first learnt the paper-rock sequence, then the rock-scissors one and finally the scissors-paper combination. Once they knew how the pairs fitted together, all the different pairs were randomly presented to them on screen. Five of the seven chimpanzees completed the training after an average of 307 sessions.

The findings show that chimpanzees can learn the circular pattern at the heart of the game. However, it took them significantly longer to learn the third scissors-paper pair than it did to grasp the others, which indicates that they had difficulty finalizing the circular nature of the pattern.*

⇒  *Or…it could indicate that they do not ever use scissors nor anything from nature that functions like scissors and so the concept of scissors was more difficult to grasp. While they do not use paper, the concept of wrapping or covering things with a light, flat object like large leaves may be in their existing cognitive constructs, but the concept of scissors seems a much larger stretch.  The fact that they learned the concept of scissors at all is pretty impressive.  Alternatively, if no constructs were attached and the presumption is that the chimps are capable of symbol learning alone, then perhaps the “v” sign used to represent scissors is also something foreign to chimps (more so than a fist or flat hand) and therefore more challenging to grasp.  For an important study on how scientific bias can affect conclusions about animal intelligence see: Apes’ abilities misunderstood by decades of poor science



“The chimpanzees’ performance during the mixed-pair sessions was similar to that of four-year-old children.”  -Jie Gao of Kyoto University in Japan and Peking University in China, and lead researcher


Journal Reference:  Jie Gao, Yanjie Su, Masaki Tomonaga, Tetsuro Matsuzawa. Learning the rules of the rock–paper–scissors game: chimpanzees versus children. Primates, 2017; DOI: 10.1007/s10329-017-0620-0