Tool use is an important aspect of being human that has assumed a central place in accounts of the evolutionary origins of human intelligence. This has inevitably focused a spotlight on any signs of tool use or manufacture in great apes and other nonhuman animals, to the relative neglect of skills that do not involve tools. The aim of this chapter is to explore whether this emphasis is appropriate. Suppose we take a broader view, accepting evidence from all manifestations of manual skill, what can we learn of the mental capacities of the great apes and the origins of human intelligence? My own ultimate purpose is to use comparative evidence from living species to reconstruct the evolutionary history of the many cognitive traits that came together to make human psychology. The cognition of great apes is the obvious starting point, to trace the more primitive (i.e., ancient) cognitive aptitudes that are still important to us today. In this chapter, I focus on great ape cognition as it is expressed in manual skills, based on cognitive aspects of tool use and manufacture considered significant in the human evolutionary lineage.

WHY IS TOOL USE IMPORTANT IN THE STUDY OF HUMAN EVOLUTION?

Consider first what aspects of tool use have recommended it as “special” to physical anthropologists and archaeologists. Most obviously, tools are convenient things for investigators. As physical objects, they can be collected, measured, and compared with ease.