Chimpanzees can learn the rules of the rock, paper, scissors game through training, matching the intellectual ability of children 4 years old or older, researchers at Kyoto University have found.

In a study that could shed light on the evolution of intellectual abilities in animals, a team of researchers led by Tetsuro Matsuzawa at the university's Primate Research Institute in Aichi Prefecture let seven chimpanzees kept at the institute play the game. The chimpanzees were shown pairs of the three tools on a computer screen and asked to choose the stronger tool in each pair.

When they picked the right answer, such as the paper in the paper-rock pair or rock in the rock-scissors pair, they were given an apple as a reward. The results showed that five of the chimpanzees mastered the game in about 100 days, the researchers said.