To examine the sociality of human beings, many approaches utilize observation of animals. Of these efforts, there are vigorous discussions about the evolutionary continuity between human beings and chimpanzees, which is the species genetically closest to humans. In particular, some of chimpanzees’ behaviors have gained attention for considerations about the origins of language. These behaviors include chimpanzees’ communication via body motions, which resemble that of human infants, and young chimpanzees’ ability to become refined in the manipulation of tools through learning until they reach around 10 years of age (Matsuzawa 1994; Tomasello & Camaioni 1997). What we wish to focus on here are performances by chimpanzees in captivity that cannot be observed for the most part in the wild. For example, chimpanzees raised in captivity have been observed to understand the meaning of human’s finger-pointing and stretch out their arms in the direction of the objected pointed to (Itakura 1996). It has also been reported that they succeed in learning to use tools at an earlier age than wild chimpanzees (Tomonaga, Tanaka, Matsuzawa, eds. 2003). The standard interpretation of these behaviors is that any chimpanzee has the ability to demonstrate them under certain conditions (Matsuzawa 2000).
This interpretation might be true. Even so, we should seriously consider under which conditions and by which methods such chimpanzees’ performances are elicited. Yet, these questions are seldom the topic of academic papers. Thus, in our research we take the following approach to explore this subject.
Chimpanzees raised in captivity have deep associations with human beings in various aspects of life. Even in research of wild chimpanzees, observers frequently take actions that habituate chimpanzees to their existence in order to make observation easier. Thus in this research, we apply the method of interaction analysis (Nishizaka 2008) to video recordings of interactions between domesticated chimpanzees and wild chimpanzees to study how actions of humans and chimpanzees in interactions are organized as time passes. We especially seek to elucidate the processes by which humans and chimpanzees use three types of semiotic resources (Goodwin 2000) as introduced below to coordinate interactions and configure interactive abilities.
Gestures: There is much research showing that chimpanzees use gestures to communicate. Meanwhile, human beings also seek to convey a variety of messages to chimpanzees through gestures.
Materials: Under captivity, chimpanzees receive different materials from humans, such as food. Chimpanzees in the wild are also known to exhibit “culture” in which each group works on different materials to use as tools.
Vocal sounds: Chimpanzees are known to use different types of vocal sounds depending on the situation. Humans also direct a variety of utterances to chimpanzees when raising them.
MEXT Grant-in-Aid for Challenging Exploratory Research – “Mutual understanding across species: Construction of ability in human-chimpanzee interactions”
Principal Investigator: Akira TAKADA (Associate Professor, Graduate School of Asian and African Area Studies, Kyoto University)
