INTRODUCTION

Imitation and tool use have both been portrayed as key abilities shaping the evolution of the human mind. The two combined – imitation of tool use – may have even greater significance. Imitation of tool use may represent a more advanced ability than imitation per se (Mitchell, 1994) and imitation may have been instrumental in promoting the acquisition and spread of tool use in hominids (e.g., Parker & Gibson, 1979; Visalberghi, 1993b). Whether any nonhuman species can imitate tool use, then, has implications for models of intelligence within the primate order, particularly evolutionary ones. The possibility that nonhumans can has begun to loom large with the increasing number of studies showing that great apes can imitate and use tools to unexpectedly sophisticated levels of complexity. This raises the credibility of the many claims of imitative tool use in great apes that have accumulated through the twentieth century.

Some newer work on imitation since the late 1980s has challenged the credibility these claims. First, great apes have independently acquired the types of tool use that were ostensibly imitatively learned (e.g., Nash, 1982; Paquette, 1992). Resemblances between great apes' tool strategies and demonstrated tool strategies could, then, derive from similarities in the affordances of the tools and the demands of the problem, that is, environmental contingencies that guide individual learning along similar paths (e.g., Galef, 1990, 1992; Whiten & Ham, 1992; Nagell, Olguin, & Tomasello, 1993; Call & Tomasello, 1994, 1995; Tomasello, 1996).