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Archaeological palimpsests are depositional units where the remains of various human occupations have been mixed for hundreds to hundreds of thousands of years. They create various sets of analytical scales that archaeologists must deal with routinely. In this paper, I argue that sociocultural processes derived from a communities of practice framework — scaffolding, guided participation, and continuity through shared activities — can be used by archaeologists to describe a palimpsest’s lithic assemblage, to differentiate its patterns, and to interpret their meaning. These processes must first be remapped onto an ecological approach to skill before they can be expanded onto new sets of scales, however. I ground my work at the site of La Martre (Quebec, Canada), a nexus of fifteen marine terraces spread over 500,000 m2. Slow depositional processes and plowing have mixed its lithic remains to create a 10,000-year-wide depositional unit with poor chronological and spatial control. Fieldwork conducted between 1995 and 1999 sampled 0.03% of its total surface. Most of its 2111 tools and 207,506 flakes were uncovered in its 40-cm-thick plowzone. I build methodological tools — dispersion surfaces, skill combinatorics, and extended skilled reduction sequences — to describe a small subset (N=93) from one of La Martre’s loci (16-west). I describe ten extended skilled reduction sequences showing various degrees of skill and knapping methods. Concepts of scaffolding, guided participation and continuity through shared activities are then used to interpret these patterns.

The identification of Oldowan hominin knapping skill levels has been a focus of numerous studies, with apparent variation in technical abilities identified between a number of Early Stone Age archaeological sites. Raw material variability, however, can play a significant role in the outcomes of knapping events as well as in the accuracy of analysis. Implications of such variability are yet to be fully understood. Here we present an experimental study to assess the effects that varying raw materials have on the identification of technological attributes typically associated with varying skill levels and whether it is possible to identify knapper skill levels across multiple raw materials. Variation was tested between raw materials from Olduvai Gorge across and between skill levels. The results suggest that knapping skill levels manifest differently in the material record across raw materials. In addition, we suggest that raw material has a significant effect on identifying knapper skill variation. This has implications for future research concerned with identifying knapper skill within and between early assemblages of differing raw materials.

One important aspect affecting variability in core reduction technology is the degree of expertise of knappers. In the present paper, we show that, at the Middle Palaeolithic open-air site of Nesher Ramla, the degree of expertise of ancient knappers played a major role in shaping the composition of the lithic assemblage. Using robust markers of knapping skill, such as the frequency and reiteration of decision mistakes in the knapping process, allowed us to establish that a clear relationship exists between the degree of structuring of core technologies and the degree of expertise of the knapper at Nesher Ramla. Simple core technologies (e.g. pebble and multiple surface cores) can be linked to the work of novices, while more structured technologies (e.g. Levallois) are linked to the work of more experienced individuals. In addition, we apply for the first time a 3D-based procedure for identifying the causes that possibly lead to knapping accidents, specifically potential errors in the evaluation of the reduction surface exterior platform angle and/or its profile. Tying simple core technologies with the work of unexpert knappers allowed us to explore otherwise elusive social-cultural aspects of past hunter-gatherer societies such as age structuring. Specifically, we suggest that during the most intense phases of occupation in Nesher Ramla, children and/or young adults were present at the site alongside adults.

This paper presents a list of macroscopic characteristics for recognizing pieces resulting from bipolar knapping. I performed specific experiments in fine-grained flint and in quartz. I describe the main characteristics of bipolar knapping in a qualitative manner and discuss the usefulness and limitations of this qualitative methodology for these two types of rocks.

Stone tool manufacture and use are considered key adaptations in human evolution. The understanding of the biomechanical features and anatomical constraints of hominins during stone tool production have received increased attention in recent years. Similarly, research on the cognitive capabilities and manipulative complexity involved in toolmaking is in progress. However, data on the palaeophysiological constraints of stone knapping are scarce. The balance between energy acquisition and energy expenditure is a key factor to determine the fitness of any individual, and stone knapping is essential for resource procurement in any Palaeolithic society. Thus, the combination of energetic analyses and experimental archaeology provides an excellent tool to improve our understanding of prehistoric behaviours. Here, we present experimental research on the energetics of stone tool production that involves nine experienced subjects. Each subject produced three handaxes through direct hard- and soft-hammer percussion in a total of 27 experiments of toolmaking. All knappers were described by their anthropometric data, and their energetic expenditure was monitored in a breath-by-breath indirect calorimetry procedure. Because knapping is considered a light-intensity level activity, based on its MET (Metabolic Equivalent Task of Intensity) value, our results show some differences in net energy expenditure between direct hard percussion and soft percussion knapping during the configuration of a handaxe. Furthermore, our results suggest that the brachial index of the subjects represents an anatomical constraint for stone knapping because the lever of a shorter forearm reduces energy expenditure during striking and represents an advantage during handaxe production. Differences in the energetic efficiency of knapping, even if they are low, may increase the general fitness of the individual and, indeed, its survival.

Stone artifacts are critical for investigating the evolution of hominin behavior—they are among our only proxies for hominin behavior in deep time. Hominin cognition and skill are often inferred by reconstructing the technical decisions hominins made throughout the knapping process. However, despite many advancements in understanding how hominins knapped, some of the key factors involved in past flake production cannot be easily/readily derived from stone artifacts. In particular, the angle at which the knapper strikes the hammer against the core to remove the flake, or the angle of blow, is a key component of the knapping process that has up to now remained unmeasurable on archeological assemblages. In this study, we introduce a new method for estimating the angle of blow from the ventral surface of flakes. This method was derived from a controlled experiment that explicitly connects fracture mechanics to flake variability. We find that a feature of the flake’s bulb of percussion, what we call the bulb angle, is a measurable indicator of the angle of blow. Our experimental finding is further validated in two additional datasets from controlled and replicative knapping experiments. These results demonstrate the utility of continuing to link flake variation with technical decision-making to fracture mechanics. In addition, they also provide a useful and relatively simple means to capture a currently invisible aspect of hominin stone tool production behavior.

The Capsian, comprising the Typical Capsian and Upper Capsian facies, is a prominent North African prehistoric entity dating to the Early Holocene. Hundreds of rammadiyat (snail-shell mound) sites in eastern Algeria and Tunisia were occupied by Capsian hunter-gatherer communities. A significant technological change occurred at these sites during the mid-seventh millennium BCE. Pressure knapping, for producing a blade and trapeze lithic industry, emerged. This technique developed during the Mesolithic throughout the Mediterranean region. Understanding the earlier typological and technological variabilities and the exact timing of the emergence of pressure knapping is crucial in determining the local or foreign origin of this innovation in North Africa. Recent examination of legacy collections excavated in the Oum el Bouaghi area of Algeria during the interwar period fosters new perspectives on Capsian lithic industry variability. Our analyses document a complex lithic landscape for the Early Holocene, including a proposed “Central Early Capsian” facies for the early phases, as well as the persistence of strong regional variabilities in Upper Capsian lithic industries.

Archaeologists have explored a wide range of topics regarding archaeological stone tools and their connection to past human lifeways through experimentation. Controlled experimentation systematically quantifies the empirical relationships among different flaking variables under a controlled and reproducible setting. This approach offers a platform to generate and test hypotheses about the technological decisions of past knappers from the perspective of basic flaking mechanics. Over the past decade, Harold Dibble and colleagues conducted a set of controlled flaking experiments to better understand flake variability using mechanical flaking apparatuses and standardized cores. Results of their studies underscore the dominant impact of exterior platform angle and platform depth on flake size and shape and have led to the synthesis of a flake formation model, namely the EPA-PD model. However, the results also illustrate the complexity of the flake formation process through the influence of other parameters such as core surface morphology and force application. Here we review the work of Dibble and colleagues on controlled flaking experiments by summarizing their findings to date. Our goal is to synthesize what was learned about flake variability from these controlled experiments to better understand the flake formation process. With this paper, we are including all of the data produced by these prior experiments and an explanation of the data in the Supplementary Information.

The morphological variability of large cutting tools (LCT) during the Middle Pleistocene has been traditionally associated with two main variables: raw material constraints and reduction intensity. Boxgrove — c.500 ka — is one of the most informative sites at which to analyze shaping strategies and handaxe morphological variability in the European Middle Pleistocene, because of the large number of finished handaxes, and the presence of complete operational chains. We focused on the entire handaxe and rough-out sample from Boxgrove-Q1/B with the aim of assessing the role of raw material characteristics — size, form, and homogeneity of nodules — in the shaping process, and to ascertain if they represent real constraints in the production of handaxes. Additionally, given the large number of handaxes and the intensity of the thinning work at Boxgrove, we also aimed to determine if reduction intensity affected the final shape to the degree that some authors have previously postulated. The methodology combines traditional technological descriptions, metrical analysis, and experimental reproduction of shaping processes together with geometric morphometry and PCA. The conclusions we draw are that the Q1/B handaxe knapping strategies were flexible and adapted to the characteristics of the blanks. These characteristics affected the reduction strategy but there is no clear relationship between initial nodule or blank morphology and final handaxe shape. Throughout the experiments, we explored the capacity to solve problems arising from reduction accidents, which led to re-configuring the knapping strategy to achieve the predetermined \"mental template.\" Furthermore, no substantial morphological differences related to reduction intensity were noticed with the Q1/B handaxes. Systematic re-sharpening as the cause of shape variation seems highly unlikely, perhaps related to the short use-life of the Boxgrove-Q1/B handaxes. Preferred forms constitute part of a broader pattern emerging for specific handaxe types at different times during the British Acheulean. The patterns have tentatively been interpreted as the result of changing environments and the movement of hominin populations.