Archaeological evidence for preferential right-handedness in the lower and middle pleistocene, and its possible implications

Abstract

Analysis of prehistoric stone artifacts from Lower Pleistocene sites at Koobi Fora, Kenya, and Middle Pleistocene horizons at Ambrona, Spain reveals a preferential, clockwise rotation of stone cores during flaking. Experimental studies of early stone artifact manufacture show that this non-random pattern is consistent with that produced by right-handed toolmakers. This suggests that there was a genetic basis for right-handedness by 1·4 to 1·9 million years ago, and that there may have already been a profound lateralization in the hominid brain with the two hemispheres becoming more specialized for different functions.