Field Experiments of Tool-Use

Abstract

This chapter introduces the “outdoor laboratory” at Bossou, which was established in 1988. Field experiments in the outdoor laboratory have provided the setting for the long-term, detailed longitudinal study of tool-use among Bossou chimpanzees. In this natural clearing at the top of Mont Gban, researchers have been providing raw materials for nut-cracking (nuts and stones) as a way to create opportunities for observing this complex tool-use behavior. The same approach in which fresh water was provided in tree hollows was adopted to study the use of leaves for drinking water. In the same location, at the same time, one may observe different kinds of tool-use, including the use of stones to crack open nuts, the use of leaves for drinking water, and the use of a stick to obtain driver ants. A field experimental approach has a clear advantage: it facilitates close observation of an individual’s tool-using ability and technique, it dramatically enhances the frequency of observations of tool-use, and it also provides us with the opportunity of comparing different tool-use behaviors simultaneously in the same locale, enabling the long-term longitudinal recording of the behavior. Consequently, we have accumulated valuable insights into learning processes underlying the acquisition of tool-use in young chimpanzees and the ways in which individuals handle the cognitive demands of each task.