Tools and language in human evolution

Humans and chimpanzees shared a common ancestor some time before 3.5 million years ago, and still share a huge proportion of their genetic material. Yet their behaviour, and the flexibility of their behaviour, are fundamentally different, despite the best efforts of ethologists and psychologists to explore the similarities. At some time in the course of human evolution these differences emerged, and we might hope that the archaeological record of humans and their ancestors could shed direct light on this process of emergence. One difference between the two species is language, naturally present in humans and not in apes. We propose that all human ancestors without language should be considered as closer to chimpanzees than to modern humans in their behaviour. Two events in the record of the prehistoric evolution of human behaviour can be said to be the first that unambiguously entail the existence of language: the colonisation of Australia, before 40000 years ago, by people crossing the sea to an unknown shore; and the appearance of sculptures and bas reliefs with coded symbols in different parts of Europe before 32000 years ago.