Stone Age humans were only able to develop relatively advanced tools after their brains evolved a greater capacity for complex thought, according to a new study that investigates why it took early humans almost two million years to move from razor-sharp stones to a hand-held stone axe.
Wikipedia on Acheulean, and Oldowan.
PLoS ONE 5(11): e13718. doi:10.1371/journal.pone.0013718
The Manipulative Complexity of Lower Paleolithic Stone Toolmaking
Aldo Faisal et al.
Early stone tools provide direct evidence of human cognitive and behavioral evolution that is otherwise unavailable. Proper interpretation of these data requires a robust interpretive framework linking archaeological evidence to specific behavioral and cognitive actions.
Here we employ a data glove to record manual joint angles in a modern experimental toolmaker (the 4th author) replicating ancient tool forms in order to characterize and compare the manipulative complexity of two major Lower Paleolithic technologies (Oldowan and Acheulean). To this end we used a principled and general measure of behavioral complexity based on the statistics of joint movements.
This allowed us to confirm that previously observed differences in brain activation associated with Oldowan versus Acheulean technologies reflect higher-level behavior organization rather than lower-level differences in manipulative complexity. This conclusion is consistent with a scenario in which the earliest stages of human technological evolution depended on novel perceptual-motor capacities (such as the control of joint stiffness) whereas later developments increasingly relied on enhanced mechanisms for cognitive control. This further suggests possible links between toolmaking and language evolution.