University of Exeter archaeology professor Bruce Bradley co-authored research which highlights how making stone tools provides some of the most abundant evidence of human behavioural change over time.
     A group of students were trained in making stone tools from the Lower Palaeolithic period. Researchers assessed the skill level of the students with brain scans, and a series of evaluations relating to the tool-making process.
     Experimental archaeologist Dietrich Stout says: "Stone toolmaking is a demanding technical skill that can take years to master. For the first time, we've shown a relationship between the degree of prefrontal brain activity, the ability to make technical judgements, and success in actually making stone tools. The findings are 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 earliest known tools are simple Oldowan stone flakes from 2.6 million years ago, and are relatively easy to make in comparison to the later Acheulean hand axe, a complex symmetrical design going back more than half a million years.
     The researchers wanted to see what parts of the brain were most actively involved in the stone technologies.
     A previous study by the same researchers showed that learning to make stone tools creates structural changes in fibre tracts of the brain connecting the parietal and frontal lobes, and that these brain changes correlated with increases in performance.
     "Making an Acheulean hand axe is hard to master due to its complexity and symmetry requiring abstract, sequential strategic thinking," explains Professor Bradley. "This type of thinking is associated with activity in the prefrontal cortex, which allows one to project what's going to happen and use this to guide subsequent actions. "Our experiments showed that when monitoring the brains there was increased activity in the prefrontal cortex, showing that making tools requires complicated thinking."

Edited from Express & Echo (22 April 2015), Culture24 (27 April 2015), PLOS One (15 April 2015)