B02

Music has played an important role in human civilization, not only as a form of art, but also in strengthening the emotional bonds of social groups. Musicality, particularly in its rhythmic and temporal structure, has even older evolutionary origins than melody, and it has been suggested that great apes share some of these features. For example, the chimpanzee auditory display, the Pant-hoot, has a temporal structure that resembles basic forms of narrative human communication, such as music and storytelling. It is also known that the integration of object use generates a variety of expressions. However, the detailed cognitive and physiological mechanisms underlying this have rarely been studied. This study therefore focuses on the rhythmic and temporal structure of auditory displays in captive chimpanzees, experimentally investigating the relationship between body movements and internal (arousal) states, the effects of object use and evolutionary factors. Based on the results obtained, the study also discusses the evolutionary processes by which humans have developed the complex rhythmic structures of expression and communication and further transformed them into musical expression with instruments.