Chimpanzee intelligence in the laboratory and in the wild

Tetsuro Matsuzawa

Kyoto University, Japan

Chimpanzees in the wild are known to develop cultural traditions unique to each community. Meanwhile, chimpanzees in the laboratory can learn various kinds of cognitive skills to adapt to a human-made environment. However, there are aspects of chimpanzee intelligence common to both the laboratory and the wild. For example, chimpanzees have the cognitive capability to relate one thing to another despite there being no intrinsic relationship between the two. This is an essential characteristic of tool use as well as symbol use. A group of chimpanzees at Bossou (n=20, range 16-22 in the 24 years since 1976) use various kinds of tools such as a set of stones as hammer and anvil for cracking open oil-palm nuts. The critical period for learning this skill is between ages of 3.5 to 5 years old, and it takes 9-10 years for the skill to reach adult levels. A group of chimpanzees at Inuyama (n=11) have learned various kinds of cognitive skills. Ai, 23-year old female has since 1978 acquired the skill of using letters and numerals to describe her visual world. However, Ai cannot use stone tools to crack open nuts in much the same way that wild chimpanzees of the Bossou community would be unable to use computer-controlled terminal. Ai’s performance in the nut-cracking task was exactly the same as that of 2.5-year-old infant chimpanzees at Bossou. When taken together, evidence from laboratory as well as wild studies of chimpanzee intelligence has demonstrated the importance of developmental, social, and environmental constraints on the learning of cognitive skills.

Matsuzawa, Tetsuro

Section of Language and Intelligence, Primate Research Institute, Kyoto University

Inuyama, Aichi 484-8506, Japan

matsuzaw@pri.kyoto-u.ac.jp