Chimpanzees at Kyoto University's Primate Research Institute have learned to play the game rock-paper-scissors. From Phys.org:
(Seven chimpanzees) 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.
"This suggests that children acquire the ability to learn a circular relationship and to solve a transverse patterning problem around the age of four years," says lead researcher Jie Gao. "The chimpanzees' performance during the mixed-pair sessions was similar to that of four-year-old children."