Brain power boost behind ancient technological advance
A boost in brain power allowed Stone Age humans to start making more complex tools, new EU-funded research suggests. Writing in the journal PLoS ONE, the team explain how they arrived at their conclusion after studying a modern-day flintknapper in action. EU support for the work came from the HANDTOMOUTH ('Hand to Mouth: A framework for understanding the archaeological and fossil records of human cognitive evolution') project, which received EUR 1.1 million under the 'New and emerging science and technology' (NEST) budget line of the Sixth Framework Programme (FP6). At the start of the Lower Palaeolithic period some 2.6 million years ago, ancient humans were making pretty basic stone tools, simply striking flint-bearing cobbles with another stone to generate razor-sharp flakes. However, it was not until 500,000 years ago that our ancestors succeeded in manufacturing large, teardrop-shaped handaxes that could be used far more widely than the more primitive flint flakes. A question which has plagued researchers for some time is why it took our ancestors 2 million years to move from producing simple sharp flakes to crafting the more complex handaxes. Some scientists have suggested that ancient humans lacked the fine motor skills required to produce a handaxe, while others have proposed that at the start of the Lower Palaeolithic, our brains were not developed enough to dream up novel, more complicated ways of working with flints to generate more complex tools. This latest study saw neuroscientists, archaeologists, anthropologists and flintknappers from Sweden, the UK and the US working together to get to the bottom of the matter. Key to the study was Professor Bruce Bradley, an experimental archaeologist at the University of Exeter in the UK who has mastered the ancient art of manufacturing flint tools. While wearing a data glove that monitored the movements of his hands and arms, Professor Bradley made a number of simple razor-sharp flakes as well as more complex handaxes. Comparing the movements involved in the production of the two tool types allowed the researchers to determine whether or not greater motor skills were needed to make the handaxes. 'We discovered that both flake and hand-held axe manufacturing techniques required the same kind of hand and arm dexterity,' said Professor Bradley. 'This enabled us to rule out motor skills as the principal factor for enabling stone tool development.' In other words, the evolution of the human brain is what allowed ancient humans to create more complex tools. The team also suggest that the rise of axe production may have coincided with the development of language; brain imaging studies have demonstrated that some of the parts of the brain involved in toolmaking are also key to our language skills. 'The advance from crude stone tools to elegant hand-held axes was a massive technological leap for our early human ancestors. Hand-held axes were a more useful tool for defence, hunting and routine work,' commented the lead author of the study, Dr Aldo Faisal of the UK's Imperial College London. 'Our study reinforces the idea that tool making and language evolved together as both required more complex thought, making the end of the Lower Palaeolithic a pivotal time in our history. After this period, early humans left Africa and began to colonise other parts of the world.' Looking to the future, the team are now keen to study Neanderthal brain development by using the same technique to investigate the knapping techniques they used across Eurasia between 150,000 and 35,000 years ago.
Countries
Sweden, United Kingdom, United States