Ideas: A History from Fire to Freud

That some major change in brain structure – in size and/or organisation – occurred about 2.5 million years ago is not in doubt. At one stage it was thought that tool-making was a defining characteristic of ‘humanity’ but that was before Jane Goodall in the 1960s observed chimpanzees pulling the leaves off twigs so they could insert the twigs into termite mounds, and then withdraw them – by now suitably coated with termites – to be eaten at leisure. Chimpanzees have also been observed cracking open nuts using stones as ‘hammers’ and, in Uganda, using leafy twigs as fans, to keep insects away. However, palaeontologists recognise two important ways in which early hominid stone tools differ from the tools produced by other primates. The first is that some of the stone tools were produced to manufacture other tools – such as flakes to sharpen a stick. And second, the early hominids needed to be able to ‘see’ that a certain type of tool could be ‘extracted’ from a certain type of rough rock lying around. The archaeologist Nicholas Toth of Indiana University spent many hours trying to teach a very bright bonobo (a form of pygmy chimpanzee), called Kanzi, to make stone tools. Kanzi did manage it, but not in the typical human fashion, by striking one stone against another. Instead, Kanzi would hurl the stones against the concrete floor of his cage. He just didn’t possess the mental equipment to ‘see’ the tool ‘inside’ the stone.¹⁵

Early stone tools similar to those found on the Gona river have also been found at Omo in southern Ethiopia, at Koobi Fora, on lake Turkana just across the border in Kenya and, controversially, in the Riwat area of northern Pakistan. In some circles these tools are referred to as the Omo Industrial Complex. The Omo industry is followed by the second type of stone tool, called Oldowan, after the Olduvai gorge, and dating to between 2.0 and 1.5 million years ago. Olduvai, in Tanzania, near the southern edge of the Serengeti plain, is probably the most famous location in palaeontology, providing many pioneering discoveries.

Stone tools, in general, do not occur in isolation. At several sites in Olduvai, which have been dated to about 1.75 million years ago, the tools were found associated with bones and, in one case, with larger stones which appear to be fashioned into a rough semi-circle. The feeling among some palaeontologists is that these large stones formed a primitive wind-break (man’s second idea?), offering shelter while animals were butchered with the early hand-axes. The stone tools in use 1.7 million years ago were already subtly different from the very earliest kinds. Louis and Mary Leakey, the famous ‘first family’ of palaeontologists, who excavated for many years at Olduvai gorge, carefully studied Oldowan technology and although by later standards the stone tools were very primitive, the Leakeys and their colleagues were able to distinguish four ‘types’ – heavy-duty choppers, light-duty flakes, used pieces and what is known as débitage, the material left over after the tools have been produced. There is still much discussion as to whether the early hominids at Olduvai were passive scavengers, or confrontational scavengers, as the Hadza are today.¹⁶