The very early hominins, living 3–4 million years ago, had well-developed hands, but their brains were too rudimentary for tool making. Even if Ardi and Lucy were able to use stones and other nearby objects for various purposes, so far there have been no indications that they were able to make tools themselves. Tool making requires imagination and a capacity for planning and abstract thinking, and it has been proposed that tool making first became possible due to the larger Homo habilis brain. But new findings, published in Nature in 2010, opened new perspectives on the issue of early tool making. Zeresenay Alemseged and associates from the California Academy of Sciences have been conducting ‘the Dikika Research Project’ in Ethiopia’s Afar region for many years. This is where fossils of hominins like Lucy were found. Marks and damage on fossilised antelope bones, dated 3–4 million years ago, clearly show that hominins used stone tools to scrape meat from bones and gain access to the bone marrow [1], about 800,000 years earlier than previously believed.

Ardi and Lucy could probably pick up and throw stones at attacking enemies, but no one can say for sure if they could also make more permanent tools for specific purposes, such as hunting and defence. It was believed that only Homo habilis presented such characteristics, and Louis Leakey argued strongly that Homo habilis was the first prehuman with a sufficiently large brain to be able to construct and make tools. However, these well-established theories are now being called into question by the data presented by Alemseged’s team.

Homo erectus has a larger brain, and the tool making associated with this species, called the Acheulian culture, is much more advanced. The tools included hand axes shaped by striking flakes off both sides of a stone to create a sharp edge. A much later type of tool making, the Mousterian culture, dated 200,000–100,000 years ago, is associated with Homo sapiens and represents a much more refined design than earlier tools. This was understood to be an indication of a more advanced capacity for imagination, planning, design and abstract and organised thinking, abilities that characterise a more developed brain. More complicated tools were made in which sharpened stones were mounted on shafts and handles to make spears and axes, projectiles and harpoons. Decorative items, including various types of ornaments, became common.

Is a larger brain really a prerequisite for making tools? Certainly not. Signs of advanced tool making were also demonstrated by Homo floresiensis, our newly discovered ‘cousin’ who lived on isolated islands in Southeast Asia until 13,000 years ago. These individuals, about 1 m in height, had extremely small brains with a volume of about 400 cc [2] but well-developed frontal lobes in the brain, indicating higher brain functions and a capacity for imagination, planning and abstract thinking [3]. Since 2002, the archaeologist Mark Moore at New England University in Armidale, Australia, has been studying stone tools made by Homo floresiensis, which were discovered in the Liang Bua cave on the island of Flores [4]. Tools made by Homo floresiensis were found in different layers of the cave along with tools originating from Homo sapiens. Some striking similarities in working techniques have been identified, and it has been speculated that these two species may at one time have lived side by side and that individuals belonging to Homo sapiens even learned from their cousins, Homo floresiensis [4]. So it makes no sense to consider only the size of the brain when it comes to a capacity for tool making; what is important, of course, is what the brain is capable of doing. The inner organisation of the brain is not reflected in its size, and indeed, the fossil findings say nothing about the inner organisation of these brains and their synaptic networks.

There are several examples of how animals with small brains can not only use tools but also, in a very clever way, determine how to make them [5]. Among birds, finches use spines from vegetation to search for insects in tree cracks, and thrushes as well as sea otters use stones to crush the shells of mussels and clams. There are stories about rooks dropping nuts on roads with heavy traffic so that cars will crush their shells; very smart individuals have been observed dropping the nuts on pedestrian crossings and then waiting for the ‘green light’ when the traffic stops and they can easily pick up the readily prepared food without the risk of being run over by cars. During antiquity, there were descriptions of how intelligent crows and rooks could drop stones into narrow containers of water to raise the water level so the bird could reach a delicious caterpillar on the surface [6].