Stone Age men used complex brain activity to craft hand axes

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A new study has revealed that Stone Age men used complex brain activity to make hand axes and so they were using sophisticated thinking, not rote actions, when creating tools.

It was found that the ability to make a Lower Paleolithic hand axe depends on complex cognitive control by the prefrontal cortex, including the "central executive" function of working memory.

The results knock another chip off theories that Stone Age hand axes are simple tools that don't involve higher-order executive function of the brain.

Dietrich Stout, an experimental archeologist at Emory University, said that the findings were relevant to ongoing debates about the origins of modern human cognition, and the role of technological and social complexity in brain evolution across species.

The skill of making a prehistoric hand axe was more complicated and nuanced than many people believed, he further added.

Stone tools, shaped by striking a stone "core" with a piece of bone, antler, or another stone, provide some of the most abundant evidence of human behavioral change over time.

Simple Oldowan stone flakes are the earliest known tools, dating back 2.6 million years. The Late Acheulean hand axe goes back 500,000 years. While it's relatively easy to learn to make an Oldowan flake, the Acheulean hand axe was harder to master, due to its lens-shaped core tapering down to symmetrical edges.

A previous study by the researchers showed that learning to make stone tools creates structural changes in fiber tracts of the brain connecting the parietal and frontal lobes, and that these brain changes correlated with increases in performance.

The study is published in the PLOS ONE.