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REVIEW
Human biological and cultural evolution are closely linked to technological innovations. Direct evidence for tool manufacture and use is absent before 2.5 million years ago (Ma), so reconstructions of australopithecine technology are based mainly on the behavior and anatomy of chimpanzees. Stone tool technology, robust australopithecines, and the genus Homo appeared almost simultaneously 2.5 Ma. Once this adaptive threshold was crossed, technological evolution was accompanied by increased brain size, population size, and geographical range. Aspects of behavior, economy, mental capacities, neurological functions, the origin of grammatical language, and social and symbolic systems have been inferred from the archaeological record of Paleolithic technology.
In the movie 2001: A Space Odyssey (1), a savanna-dwelling ape has a eureka-like flash of inspiration when he realizes the awesome power of the bone tool in his hands. He tosses it skyward, where it morphs into a space station at the dawn of this millennium. What happened between the first tool use by our ape ancestors and the first complex projectile launched into flight with another tool? In this review, conventional wisdom about aspects of Paleolithic technology will be challenged, and new ideas about the coevolution of technology, language, hands, and brains will be proposed.
How did technology influence human evolution? What were the "prime movers" for the origin and development of Paleolithic technologies? Palec,anthropologists once considered making tools to be one of the defining characteristics of the genus Homo (2). However, the diversity of tool-making and toolusing behaviors among chimpanzees (Pan troglodytes) has forced us to completely revise assumptions surrounding the concept of "man the toolmaker," including those about the gender of the first tool users. Chimpanzees have diverse and regionally varied repertoires of tool-using, tool-making, and other "cultural" behaviors (3-5). In contrast, Cebus monkeys are considered prolific tool users but exhibit no understanding of cause and effect, or of the difference between appropriate and inappropriate tools (6).
Chimpanzees make and use several kinds of tools for extractive foraging (3), including leaf sponges, termite and ant fishing wands and probes, marrow picks, levers, pestles, stick brushes for honey extraction, leaf scoops, and hooked sticks to extend their reach. West African chimpanzees use wood and stone hammers and anvils for cracking nuts (7). Repeated use produces shallow dimpled...