In yet more proof that chimpanzees are scarily close to their human relations, scientists have been able to teach the primates how to play a children’s game as well as a four-year-old person.
The team’s objective in teaching the monkeys ‘rock, paper, scissors’ wasn’t just to help keep the animals entertained, but instead to work out if they are able to grasp extended patterns in the same way as people.
They found this was a particularly good way because the relationship between the hand signals in the game (clenched fist, flat palm, open fingers) is nonlinear during play and must be understood in the context of how the pairs interact.
For example, scissors cut paper, and rock blunts scissors.
They found that chimpanzees of all ages, and both sexes, can learn to play the game although it does take them far longer than humans (even toddlers).
Jie Gao, lead author from Kyoto University in Japan and Peking University in China, said: “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. The chimpanzees’ performance during the mixed-pair sessions was similar to that of four-year-old children.”
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.
During the experiment the chimpanzees sat in a booth with a computer touchscreen, first they learnt the paper-rock sequence, then the rock-scissors one and finally the scissors-paper combination.
Once they knew how they were all related they were randomly presented with pairs on the screen.
Five of the seven chimps completed the training after an average of 307 sessions, compared to preschool children who only took 5 sessions (and became more accurate the older they got).
Whereas chimpanzees were not better with age.
It also took the animals significantly longer to learn the third scissors-paper pair than the other pairs, suggesting they had difficulty finalising the circular nature of the pattern.