抄録
The Rock-Paper-Scissors (RPS) game is the simplest example of intransitive dominance, where “P” beats “R”, “R” beats “S”, and “S” beats “P”. In order to investigate the learning process of the circular relationship in chimpanzees, seven chimpanzees were trained with tests that have two figures representing two of the three elements respectively in each trial, in the order that first “PR” a session, “RS” a session, “SP” a session, and then mixed pairs in one session. Four chimpanzees had high performances in the single trial sessions, while two chimpanzees were stuck at the third pair, “SP” for long. The results suggest that chimpanzees could have the ability of learning the intransitive relationship, but they showed some difficulty to finalize “circularity” of the relationships among the three items. We incidentally started from “PR”, but the same results will be obtained if we started from “SP”. This study may facilitate the understanding of chimpanzees' cognitive abilities in intransitive relationships, as well as the origin of that in human mind.
