A study from Kyoto University's Primate Research Institute established something that will make you rethink your next loss to a casual player: chimpanzees can learn Rock Paper Scissors. Not as a button-pressing trick — they can learn the actual circular logic of the game. Paper beats Rock beats Scissors beats Paper beats Rock. The loop. Seven chimps learned it using a touchscreen, and they performed at roughly the level of a human four-year-old.
The training took a while. Researchers worked with seven chimpanzees, teaching them the relationships one pair at a time. The correct pairing appeared on a touchscreen and they'd select it for a reward. Paper over Rock took an average of 1.7 sessions to learn. Rock over Scissors took 3.1 sessions. The last pair — Scissors over Paper — averaged 14.3 sessions. That's not because the chimps struggled specifically with Scissors. It's because they were struggling with circularity. The game isn't just three win/lose pairs. It's a loop, and loops are cognitively harder than linear hierarchies. Five of the seven chimps completed full training, averaging 307 sessions across the whole process.
For comparison, the researchers ran the same experiment with 38 children between three and six years old. Kids over 50 months — roughly four years old — understood the game clearly. Younger ones guessed randomly. Average sessions to mastery: five. So children are dramatically faster, but the chimps got there. The point isn't that chimps and toddlers play at the same level. It's that the cognitive capacity to understand cyclic relationships isn't uniquely human.
Our last common ancestor with chimpanzees lived approximately six million years ago, and the researchers argue the evidence suggests that ancestor had the mental architecture for this kind of relational reasoning. The game requires understanding that dominance isn't transitive: Rock dominates Scissors which dominates Paper which dominates Rock. There's no single best move. That's the same kind of non-hierarchical thinking that shows up in social networks, ecological systems, and market dynamics. It's not a trivial computation. The fact that chimps can learn it — slowly and with a lot of sessions — suggests the capacity is old and shared, not a recent human development.
The evolutionary angle aside, there's something genuinely interesting about the training data itself. The Scissors-over-Paper pair taking eight times as many sessions as Paper-over-Rock tells you something about how the chimps were building their model of the game. They were likely forming sequential dependencies — if A then B — rather than a unified relational structure. The circular completion broke that approach. Getting from "these three pairs are all true" to "this forms a closed loop" is the cognitive step that took hundreds of sessions. Most humans learn it as children and forget that it was ever hard.
Future research plans, as of the study's publication, included cross-cultural chimp trials — testing whether Japanese and American chimpanzees would play consistently against each other. A global chimpanzee Rock Paper Scissors tournament is probably not imminent. But it is now a thing that has been proposed by actual researchers and is not technically impossible. That's a sentence that didn't exist before 2014.