Effective tool choice by chimpanzees (Pan troglodytes): Learning and flexibility

Chimpanzees are proficient tool users and have been shown to use properties of weight and length to select effective tools. Researchers have, however, neglected to investigate whether chimpanzees utilize other tool properties. This study investigated whether chimpanzees use other properties to choose effective tools, how feedback influences their ability to select effective tools, and whether or not chimpanzees are flexible in effective tool selection. Sixty-one chimpanzees, ages 17-52 years, underwent four probing tasks requiring tools of differing physical properties. The results demonstrate that chimpanzees are able to utilize properties of length, surface area, and shape to select effective probing tools. Though exploration of the environment is suggested to facilitate learning and/or performance, it did not have an effect as measured through looking. Together, these results support prior research concerning effective tool selection by chimpanzees, as well as expand current knowledge and understanding of what may underlie effective tool selection. INDEX WORDS: Tool use, Tool effectiveness, Flexibility, Learning, Optimal foraging, Cognition EFFECTIVE TOOL CHOICE BY CHIMPANZEES (PAN TROGLODYTES): LEARNING AND FLEXIBILITY