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ABSTRACTThe Oldowan is the archaeological record’s oldest consistent evidence of hominin technical behavior. First appearing ∼2.6 Ma in East Africa, the Oldowan is characterized by simple core and flake technology using direct hard hammer percussion. Archaeologists debate whether Oldowan assemblages are uniform and what role hominin cultural abilities played in generating these assemblages. To improve existing methods for studying Oldowan technical uniformity, we conducted experiments involving 23 novices and one expert knapper. Subjects made simple stone tools under two different instructional conditions (observation-only and direct active instruction) over two hours. We used the resulting cores to track flaking efficiency, reduction intensity, and knapping errors. We find significant differences in the expert and novice core uniformity. Direct active teaching increased core flaking efficiency and reduced knapping errors. Comparisons between our experimental results and an Oldowan sample from Gona, Ethiopia, show core variability patterns that match our expert and actively taught novices.

The article focuses on the use of brain scanning methods to investigate changes to neural structures in the brain resulting from tool-making activities. It states positron-emission tomography, magnetic resonance imaging, and diffusion tensor imaging was used to examine neural changes caused by stone tool knapping and crafting using Oldowan and Late Acheulean techniques. It mentions plasticity to the frontal gyrus and the supra-marginal gyrus, and how tool use influenced language development.

Despite the extensive literature focusing on Acheulean handaxes, especially the sources and meaning of their morphological variability, many aspects of this topic remain elusive. Archaeologists cite many factors that contribute to the considerable variation of handaxe morphology, including knapping skill and mental templates. Integrating these two lines of literature into a broader theoretical framework of cultural reproduction, here we present new results from a multidisciplinary study of Late Acheulean handaxe-making skill acquisition involving thirty naïve participants trained for up to 90 hours in Late Acheulean style handaxe production and three expert knappers. We compare their handaxe to the Late Acheulean handaxe assemblage from Boxgrove, UK. Through the principal component analysis of morphometric data derived from images, our study suggested that knapping skill acquisition has a differential effect in the cultural reproduction of different aspects of handaxe morphology. More specifically, compared with elongation and pointedness (PC2), cross-sectional thinning (PC1) is more constrained by knapping skill. Our findings thus shed new light on how the processes of skill learning can bias the cultural reproduction of artifact morphology.

This study introduces to archaeology a new experimental technique for examining the relationship between stone tool-making and brain function. The principal focus of this exploratory study was the development of effective methods for the identification and examination of the regions of the modern human brain recruited during the manufacture of simple (Oldowan or Mode I) stone tools. The functional brain imaging technique employed, Positron Emission Tomography (PET), examines task-related brain activity by assessing changes in regional cerebral blood flow during specific tasks. The single-subject study reported here represents a heuristic, initial exploration of this subject. Results indicate that during stone tool-making there was heavy activation of cortical and subcortical regions of the brain associated with motor and somatosensory processing. Especially interesting was the high degree of activation in areas known to be involved with complex spatial cognition requiring integration of diverse sensory inputs (e.g. vision, touch, and proprioception, or sense of body position and motion). Expansion of such higher-order association areas has been particularly important during the course of human evolution. This single-subject pilot study demonstrates the application of the PET brain imaging technique to the study of early stone technologies and suggests hypotheses to be tested in more comprehensive studies in the future.