Brain Evolution Allows for Complex Stone Age Tools

In a recent investigation, researchers showed that it was changes in the brains of hominids living in the Stone Age that allowed for them to start creating more complex tools.

For many years, historians and anthropologists have been wondering as to what was it exactly that allowed our ancestors living in the Stone Age to begin fashioning complex tools.

One side of the argument holds that the evolution of the brain was the main driving force behind innovation, while others say that the evolution of the hand allowed for this to happen.

The new investigation reveals that producing advanced tools only became possible when the brain developed the ability to plan complex tasks. This is an ability humankind had to learn.

Before our ancestors could do this, they were limited in their tool-making techniques to chopping pieces of rocks, and using them as weapons.

When their brain developed enough, they became capable of fashioning complex stone battle axes, that were significantly more advanced and effective than the previous weapons, researchers say.

For the new study, researchers at the Emory University used a cyber data glove on experts that were constructing ancient stone tools. The movements of their hands were precisely measured.

At the same time, brain imaging techniques were used to determine patterns of brain activation. These data were then correlated with the hand gestures, and experts were able to infer which of the tasks was the most demanding.

Details of the research are published in the November 3 issue of the Public Library of Science journal PLoS ONE, a peer-reviewed, open-access journal.

“Making a hand ax appears to require higher-order cognition in a part of the brain commonly known as Broca's area,” explains study coauthor Dietrich Stout.

This particular region of the brain is associated with hierarchical planning and language processing, which would appear to suggest that tool-making abilities developed at the same time as language skills.

“The leap from stone flakes to intentionally shaped hand axes has been seen as a watershed in human prehistory, providing our first evidence for the imposition of preconceived, human designs on the natural world,” the Emory University anthropologist says.

“Changes in the hand and grip were probably what made it possible to make the first stone tools. Increasingly we're finding that the earliest tools required visual and motor skills, but were conceptually simple,” the expert concludes.

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