To ensure proper context control for archaeological samples, it is crucial that excavations determine and,where possible, follow the natural stratigraphic subdivisions in a sedimentary sequence.... Show moreTo ensure proper context control for archaeological samples, it is crucial that excavations determine and,where possible, follow the natural stratigraphic subdivisions in a sedimentary sequence. In cases with a single,unchanging source of sedimentary input, this may pose challenges. We present our strategies to deal with a>2 m deep homogeneous Pleistocene stratigraphy at Umhlatuzana rockshelter in South Africa, yieldingarchaeological remains from the Middle Stone Age. The site was originally excavated during a rescue project in 5–10 cm deep artificial spits for lack of visible stratigraphy. We revisited the shelter in 2018 and 2019. We integrate current standard practice such as piece-plotting archaeological materials with digital methods such as cluster analysis and geoarchaeological analyses (e.g., micromorphology, sedimentological analyses, geochemical analyses) to track the different sources of sedimentary input. We also develop an intensive sediment sampling strategy to illuminate geochemical variation within the sequence and postdepositional alterations affecting preservation conditions. We manage to reconstruct a natural stratigraphy of the site combining these methodologies, resulting in a radically changed understanding of the stratigraphy, depositional environment, and mechanisms of postdepositional disturbance. Show less
Schmid, V.C.; Sifogeorgaki, I.; Dusseldorp, G.L.; Chu, W. 2023
Raw materials are the lowest common denominator of any debitage analysis. And yet, the fracture mechanicsof eccentric raw materials are not always fully considered when performing inter-/intra... Show moreRaw materials are the lowest common denominator of any debitage analysis. And yet, the fracture mechanicsof eccentric raw materials are not always fully considered when performing inter-/intra-assemblagecomparisons. The fracture mechanics as one constraint to be respected by the knappers greatly influencearchaeological recovery of debitage products in different raw materials. Thus, our methodologies forrecording debitage morphometrics may need to be adapted to specific raw materials. This means assemblagecomparison and correlation can only be attempted in a context-dependent manner. We review results ofassemblages in both chert and other raw materials from a range of locations across Old World to examinehow such assemblages have been recorded. In doing so, we highlight various pitfalls and limitations, andpropose that it is very important to provide the contextual information and describe exactly what methodwas used and give arguments, why it was used. Show less
We develop a study protocol to efficiently and accurately identify the raw material categories constituting the lithic assemblages at Umhlatuzana rockshelter, South Africa. We combine visual and... Show moreWe develop a study protocol to efficiently and accurately identify the raw material categories constituting the lithic assemblages at Umhlatuzana rockshelter, South Africa. We combine visual and analytical methods to establish a raw material database and to provide a more accurate insight into raw material selection during the Pleistocene Middle and Later Stone Age occupational sequence of Umhlatuzana. The protocol combines petrological properties (as studied on micromorphological samples), elemental composition of the specimens (as measured with p-XRF) and visual characterization by lithic analysts. We tested the protocol by applying it to a sample of piece-plotted lithics from four spits across the stratigraphic sequence. We document the intensive use of sandstone accounting for 25% of the tested sample. We also report a larger importance of hornfels and lower proportion of quartz than was reported in previous analyses (Kaplan 1990). The combination of micromorphological and p-XRF analysis of the Umhlatuzana assemblages demonstrates that with only visual inspection, the variability of raw materials used may be misinterpreted. With accurate raw material datasets, we are better equipped to answer techno-economic questions of the southern African Stone Age. Show less
Analysis of Late Pleistocene fauna exploitation (~130,000–12,000 years ago) in southern Africa is of global academic relevance. Faunal analyses from southern African sites have led to the... Show moreAnalysis of Late Pleistocene fauna exploitation (~130,000–12,000 years ago) in southern Africa is of global academic relevance. Faunal analyses from southern African sites have led to the development of influential hypotheses on the evolution of modern human hunting methods and subsistence economies. In the 1970s and 1980s, analysis of faunal remains from the Middle Stone Age site Klasies River informed the hypothesis that Middle Stone Age humans were less effective hunters than ethnographically documented huntergatherers. This was based on the underrepresentation of dangerous prey species in the bone assemblages. The development of detailed taphonomic research in the 1990s and 2000s demonstrated that the accumulation of faunal assemblages was the result of complex processes involving both human and nonhuman agents. These studies helped establish that Middle Stone Age hunters were as capable as those in ethnographically documented societies. Since then, important progress has been made in the identification of the weapons systems that were used to hunt animals. Analyses of lithic implements indicate bow-and-arrow use in southern Africa going back to at least 65,000 years ago. Animal exploitation strategies do change over time. Hunting strategies probably focused on large antelope during the Middle Pleistocene, and the importance of smaller animals increased This change was likely caused by a shift in prey populations that stemmed from a combination of environmental change and perhaps human population pressure. Late Pleistocene archaeological sites show increasing evidence for intensification; that is, an increase in the amount of food extracted from the environment by more thorough processing of prey, exploitation of new prey types, and development of new exploitation strategies. This pattern is usually linked to animal overexploitation and may be a result of human population expansion or environmental change if decreasing productivity limits the supply of animal prey. Notable examples of this are shellfish middens at coastal sites, the abundance of tortoises, and the presence of large numbers of small mammals that were likely snared instead of pursued. Show less
A destructive force across entire landscapes, mining at times threatens the preservation of priceless archaeological sites across southern Africa. The UNESCO World Heritage site of the Mapungubwe... Show moreA destructive force across entire landscapes, mining at times threatens the preservation of priceless archaeological sites across southern Africa. The UNESCO World Heritage site of the Mapungubwe Cultural Landscape is one of the recent legal battlegrounds pitting the interests of the natural world and archaeological heritage against mining. Mineral resource extraction carries within its destruction creative potential too. In southern Africa mining has been instrumental in illuminating human history and in the creation of archaeological landmarks.The relationship between archaeology and mining is a complex one. The gold industry and associated lime-mining has specifically been instrumental in the development of palaeoanthropology in South Africa (Bonner 2007). With the discovery of gold, lime was required for the desulfurization process. This was obtained locally and many lime works were exploited during the 1890s (Esterhuysen 2019). The miners drew attention to fossils found within the deposits leading to the discovery of hominins at Taung, Makapan and Sterkfontein in the early 20th century. Mining may thus be seen as crucial to the genesis of the Cradle of Humankind UNESCO World Heritage site in South Africa. Similarly guano, zinc and vanadium mining have yielded important palaeoanthropological finds in southern Africa.In the 19th and early 20th century, scientific focus was on discovering unknown objects. In this context, the efficient removal of great quantities of overburden was a great asset. With increasing scientific rigour in the 20th century, archaeological focus shifts from objects to their interrelationships and their context. The documentation of finds and find contexts requires time that is not available in the context of industrial resource extraction. Fruitful collaboration now becomes more difficult. As the early lime works closed down in the first half of the 20th century, archaeologists were free to continue work at a comparative snail’s pace but yielding far greater insight in the human past.In active mining operations, collaboration is difficult. While mining still exposes valuable sites and materials that would otherwise be inaccessible, this is of limited value in current archaeological practice. Current ethical standards emphasise in situ preservation of archaeological remains over excavation. When finds are documented, the time-pressure from mining companies makes these situations ambiguous in value. Examples are the discovery of Pleistocene shell middens after their partial destruction, or the recovery of lithic materials from conveyor belts in diamond plants.In the late 20th century and 21st century, the discipline of archaeology has been included in legal frameworks on environmental planning. Archaeological contractors conduct Heritage impact assessments and advise on mitigation measures for large-scale environmental projects such as mining operation and the building of large dams of infrastructure works.Highlighting human history was an unintended consequence for large mining operations. Yet both on a grand level, the activity of mining, as well as on a personal level, the activities of miners and foremen have played a crucial role in uncovering ancient humans and their world in southern Africa. I argue that the insights produced as a result of early resource extraction are one (albeit often minor) consideration in the network of values, stakeholders and resources that embed mining operations in society. Show less
Here we evaluate the hypothesis that during cold climatic phases, people and resources became increasingly packed along highland Lesotho's riverine corridors as the viability of palatable... Show moreHere we evaluate the hypothesis that during cold climatic phases, people and resources became increasingly packed along highland Lesotho's riverine corridors as the viability of palatable grasslands for large mammal hunting on the upland plateaus declined. These intensification efforts resulted in increased reliance on lower-ranked aquatic (fish) resources with knock-on effects for lithic technological organization. We compare data on the relative contributing of fishing to the diets of highland hunter-gatherers at Sehonghong rockshelter with a faunal proxy widely argued to correlate with subsistence intensification (faunal assemblage evenness). In addition, we compare these data with two measures of lithic technological intensification (cutting edge production and core reduction intensity) to test whether diet intensification tracks technological intensification. We show that at Sehonghong, aquatic resource exploitation is not always correlated with faunal assemblage evenness. We find that some layers (i.e. RF) show spikes in aquatic resource use irrespective of changes in mammal hunting. Other layers (i.e. layer RBL/CLBRF) were intensively occupied, but they do not have many fish. Our data also demonstrate that aquatic resource use is not associated with lithic technological intensification. These results suggest that while aquatic resource exploitation was a ‘fallback’ option for some of Lesotho's highland hunter-gatherers, there is considerable variability. Our data show that multiple intensification dimensions were variably combined through the Late Pleistocene at Sehonghong as they were elsewhere in southern Africa. Show less
Lombard, M.; Bradfield, J.; Caruana, M.V.; Makhubela, T.V.; Dusseldorp, G.L.; Kramers, J.D.; Wurz, S. 2022
A decade ago, we summarised the South African and Lesotho Stone Age technocomplex sequence as a heuristic exercise, anchored in 242 dated assemblages (Lombard et al. 2012). Following Clarke (1968),... Show moreA decade ago, we summarised the South African and Lesotho Stone Age technocomplex sequence as a heuristic exercise, anchored in 242 dated assemblages (Lombard et al. 2012). Following Clarke (1968), Sampson (1974) and Deacon (1980), we defined a technocomplex as a group of industries characterised by assemblages that have many, but not all, properties in common. Spatiotemporal changes and shifts in artefact design and frequencies owing to material use/availability and socio-economic factors are built into the framework. The accompanying dataset was intended to serve as a useful resource to both students and professionals, and to fuel research and debate. Show less
Umhlatuzana is an important archaeological site for the study of the Middle and Pleistocene Later Stone Age in South Africa with a largely continuous occupation sequence spanning MIS 4-2 (~70,000 -... Show moreUmhlatuzana is an important archaeological site for the study of the Middle and Pleistocene Later Stone Age in South Africa with a largely continuous occupation sequence spanning MIS 4-2 (~70,000 - 10,000 BP). The main technocomplexes represented are Still Bay, Howiesons Poort, Sibudan, final MSA and Robberg (from old to young). Changing selection of raw materials is an important issue in the study of the Middle-to-Later Stone Age transition that appears characterised by a shift in raw material use in addition to a technological organisation. Umhlatuzana was first excavated in 1975 by Jonathan Kaplan who suggested that the lithic assemblage of the Pleistocene deposits consisted mainly of quartz (61%), hornfels (37.6%), and quartzite (1.4%) (Kaplan 1990). Renewed excavations at the site were conducted during 2018 and 2019. This campaign aims to clarify the site’s formation processes employing micromorphological analysis and other techniques (Reidsma et al. 2021, Sifogeorgaki et al. 2020). Micromorphology uses thin sections of undisturbed sediment samples for microscopic studies. The sections allow a petrological inspection of rock fragments embedded in the deposits. Rather unexpectedly, the Umhlatuzana thin sections yield different raw material determinations than Kaplan (1990). While quartz and hornfels are present (around 23% and 25% respectively), they represent a much less sizable proportion than previously reported. Instead, the most prominent raw material observed is a quartz arenite sandstone (42%). Quartzite fragments were not detected.We therefore initiated an in-depth mineralogical and elemental classification of the raw materials. We distinguish 6 raw material types based on the thin section analysis: sandstone, quartz, hornfels, dolerite, chert and diorite. We then determined the elemental composition of the raw material types of the micromorphology samples using p-XRF. Additionally, p-XRF analysis was conducted on c. 100 specimens from the 2018-2019 excavation lithic collection. This allowed us to determine elemental characteristics of the raw materials used during the Pleistocene occupation of the site. Subsequently, p-XRF analysis was systematically performed on a larger sample set of lithics from the site in order to correctly determine their raw material type. The combination of micromorphological and p-XRF analysis of the Umhlatuzana assemblages demonstrates that if only visual inspection is done, the variability of raw materials used may be misinterpreted and the relative frequency of different rock types in an assembly may be over- or underestimated. Future work will aim at re-visiting the raw material categorization of artefacts excavated during the 1975 excavations. Show less
Murungi, M.; Esteban, I.; Sifogeorgakis, E.; Dusseldorp, G.L. 2021
The period between ~40 and 20 ka BP encompassing the Middle Stone Age (MSA) and Later Stone Age (LSA) transition has long been of interest because of the associated technological change.... Show moreThe period between ~40 and 20 ka BP encompassing the Middle Stone Age (MSA) and Later Stone Age (LSA) transition has long been of interest because of the associated technological change. Understanding this transition in southern Africa is complicated by the paucity of archaeological sites that span this period. With its occupation sequence spanning the last ~70,000 years, Umhlatuzana Rock Shelter is one of the few sites that record this transition. Umhlatuzana thus offers a great opportunity to study past environmental dynamics from the Late Pleistocene (MIS 4) to the Late Holocene, and past human subsistence strategies, their social organisation, technological and symbolic innovations. Although organic preservation is poor (bones, seeds, and charcoal) at the site, silica phytoliths preserve generally well throughout the sequence. These microscopic silica particles can identify different plant types that are no longer visible at the site because of decomposition or burning to a reliable taxonomical level. Thus, to trace site occupation, plant resource use, and in turn reconstruct past vegetation, we applied phytolith analyses to sediment samples of the newly excavated Umhlatuzana sequence. We present results of the phytolith assemblage variability to determine change in plant use from the Pleistocene to the Holocene and discuss them in relation to taphonomical processes and human plant gathering strategies and activities. This study ultimately seeks to provide a palaeoenvironmental context for modes of occupation and will shed light on past human-environmental interactions in eastern South Africa. Show less
The Dutch wetlands witness the gradual adoption of Neolithic novelties by foraging societies during the Swifterbant period. Recent analyses provide new insights into the subsistence palette of... Show moreThe Dutch wetlands witness the gradual adoption of Neolithic novelties by foraging societies during the Swifterbant period. Recent analyses provide new insights into the subsistence palette of Middle Swifterbant societies. Small-scale livestock herding and cultivation are in evidence at this time, but their importance if unclear. Within the framework of PAGES Land-use at 6000BP project, we aim to translate the information on resource exploitation into information on land-use that can be incorporated into global climate modelling efforts, with attention for the importance of agriculture. A reconstruction of patterns of resource exploitation and their land-use dimensions is complicated by methodological issues in comparing the results of varied recent investigations. Analyses of organic residues in ceramics have attested to the cooking of aquatic foods, ruminant meat, porcine meat, as well as rare cases of dairy. In terms of vegetative matter, some ceramics exclusively yielded evidence of wild plants, while others preserve cereal remains. Elevated δ15N values of human were interpreted as demonstrating an important aquatic component of the diet well into the 4th millennium BC. Yet recent assays on livestock remains suggest grazing on salt marshes partly accounts for the human values. Finally, renewed archaeozoological investigations have shown the early presence of domestic animals to be more limited than previously thought. We discuss the relative importance of exploited resources to produce a best-fit interpretation of changing patterns of land-use during the Middle Swifterbant phase. Our review combines recent archaeological data with wider data on anthropogenic influence on the landscape. Combining the results of plant macroremains, information from pollen cores about vegetation development, the structure of faunal assemblages, and finds of arable fields and dairy residue, we suggest the most parsimonious interpretation is one of a limited land-use footprint of cultivation and livestock keeping in Dutch wetlands between 4600 and 3900 BCE. Show less
Umhlatuzana rockshelter is an archaeological site with an occupational record covering the Middle Stone Age, Later Stone Age, and Iron Age. The presence of both Middle and Later Stone Age... Show moreUmhlatuzana rockshelter is an archaeological site with an occupational record covering the Middle Stone Age, Later Stone Age, and Iron Age. The presence of both Middle and Later Stone Age assemblages makes Umhlatuzana the ideal location for the study of the MSA–LSA transition (20–40 ka) in southern Africa. This transitional period is characterized by important modifications in stone tool technology, from prepared core technology to a toolkit based on microlith production. These changes are argued to have occurred in response to changes in climate and environment leading up to the Last Glacial Maximum. The deposits bearing the transitional assemblages at Umhlatuzana rockshelter appear homogeneous with no visible stratigraphic boundaries. This study integrates geoarchaeological techniques in order to explore fine-resolution geochemical differentiations of the sediments that are macroscopically invisible, and that will provide insight into (post-)depositional processes over time. Samples were systematically retrieved from the western profile of the site following a grid-based sampling strategy and analyzed for pH, elemental composition (XRF), and Magnetic Susceptibility. Additionally, the results were integrated with preliminary micromorphological observations. Our study reveals a steady, gradual change in the geochemistry of the deposits throughout the Pleistocene, related to a combination of environmental change and occupation intensity. We suggest that the part of the sequence reported to bear Middle to Later Stone Age transitional industries is characterized by wetter environmental conditions compared to the underlying deposits. Additionally, we support results from previous studies that excluded large scale post-depositional movement of the sedimentary sequence. Our study offers a successful multi-proxy approach to systematically sample and study archaeological deposits at the macro and micro scale, integrating a variety of geoarchaeological techniques. The approach provides insight into the depositional and post-depositional history of the site, and allows for questions of stratigraphic integrity, anthropogenic input, preservation, and environmental change to be addressed. Show less
Umhlatuzana rockshelter is an archaeological site with an occupational record covering the Middle Stone Age, Later Stone Age, and Iron Age. The presence of both Middle and Later Stone Age... Show moreUmhlatuzana rockshelter is an archaeological site with an occupational record covering the Middle Stone Age, Later Stone Age, and Iron Age. The presence of both Middle and Later Stone Age assemblages makes Umhlatuzana the ideal location for the study of the MSA-LSA transition (20-40 ka) in southern Africa. This transitional period is characterized by important modifications in stone tool technology, from prepared core technology to a toolkit based on microlith production. These changes are argued to have occurred in response to changes in climate and environment leading up to the Last Glacial Maximum. The deposits bearing the transitional assemblages at Umhlatuzana rockshelter appear homogeneous with no visible stratigraphic boundaries. This study integrates geoarchaeological techniques in order to explore fine-resolution geochemical differentiations of the sediments that are macroscopically invisible, and that will provide insight into (post-)depositional processes over time. Samples were systematically retrieved from the western profile of the site following a grid-based sampling strategy and analyzed for pH, elemental composition (XRF), and Magnetic Susceptibility. Additionally, the results were integrated with preliminary micromorphological observations. Our study reveals a steady, gradual change in the geochemistry of the deposits throughout the Pleistocene, related to a combination of environmental change and occupation intensity. We suggest that the part of the sequence reported to bear Middle to Later Stone Age transitional industries is characterized by wetter environmental conditions compared to the underlying deposits. Additionally, we support results from previous studies that excluded large scale post-depositional movement of the sedimentary sequence. Our study offers a successful multi-proxy approach to systematically sample and study archaeological deposits at the macro and micro scale, integrating a variety of geoarchaeological techniques. The approach provides insight into the depositional and post-depositional history of the site, and allows for questions of stratigraphic integrity, anthropogenic input, preservation, and environmental change to be addressed. Show less
Umhlatuzana rockshelter is an archaeological site with an occupational record spanning the last ~70,000 years, covering the Middle Stone Age (MSA), Later Stone Age (LSA), and Iron Age. The deposits... Show moreUmhlatuzana rockshelter is an archaeological site with an occupational record spanning the last ~70,000 years, covering the Middle Stone Age (MSA), Later Stone Age (LSA), and Iron Age. The deposits bearing Pleistocene archaeological assemblages at Umhlatuzana rockshelter appear homogeneous with no macroscopically visible stratigraphic boundaries. This means the integrity of the archaeological assemblages is difficult to ascertain. Moreover, the sedimentation rate, taphonomic history, and the environmental context across the sequence are unclear. This study aims to resolve these issues by integrating different geoarchaeological techniques in order to explore fine-resolution geochemical differentiations of the sediments that are macroscopically invisible. Samples were systematically retrieved from the western profile of the site following a grid-based sampling strategy and analysed for pH, elemental composition (XRF), and Magnetic Susceptibility. These methods were chosen because they provide insight into ‘invisible’ geoarchaeological dynamics, related to sediment input (geogenic and anthropogenic), taphonomy, and environmental conditions. Additionally, the results were integrated with preliminary micromorphological observations. Our study reveals a gradual change in the geochemistry of the deposits throughout the Pleistocene, related to a combination of environmental change and occupation intensity. Furthermore, the gradual change within the geochemical data indicates that no large-scale sediment mixing took place (contrary to previous suggestions), while small-scale mixing related to bioturbation is visible in the micromorphological thin sections. Our study offers a successful multi-proxy approach to systematically sample and analyse archaeological deposits at the macro and micro scale, integrating a variety of geoarchaeological techniques. The approach provides insight into the depositional and postdepositional history of the site, and allows questions of stratigraphic integrity, anthropogenic input, preservation, and environmental change to be addressed. Show less
The causes of Neanderthal disappearance about 40,000 years ago remain highly contested. Over a dozen serious hypotheses are currently endorsed to explain this enigmatic event. Given the relatively... Show moreThe causes of Neanderthal disappearance about 40,000 years ago remain highly contested. Over a dozen serious hypotheses are currently endorsed to explain this enigmatic event. Given the relatively large number of contending explanations and the relatively large number of participants in the debate, it is unclear how strongly each contender is supported by the research community. What does the community actually believe about the demise of Neanderthals? To address this question, we conducted a survey among practicing palaeo-anthropologists (total number of respondents = 216). It appears that received wisdom is that demography was the principal cause of the demise of Neanderthals. In contrast, there is no received wisdom about the role that environmental factors and competition with modern humans played in the extinction process; the research community is deeply divided about these issues. Finally, we tested the hypothesis that palaeo-anthropologists’ stand in the debate co-varies with their socio-political views and attitudes. We found no evidence for such a correlation. Show less
Archeologisch onderzoek heeft soms wel wat weg van een murder mystery. Vrijwel de gehele prehistorie, op de laatste 40.000 jaar na, leefden er meerdere mensensoorten tegelijk. Ze leefden ook vaak... Show moreArcheologisch onderzoek heeft soms wel wat weg van een murder mystery. Vrijwel de gehele prehistorie, op de laatste 40.000 jaar na, leefden er meerdere mensensoorten tegelijk. Ze leefden ook vaak in hetzelfde gebied. En de stenen werktuigen die we opgraven, zien er meestal vrij eender uit. Hoe weten we nu wie die werktuigen maakten? Met mijn Zuid-Afrikaanse collega Marlize Lombard heb ik een onderzoek gepubliceerd waarin we een aanpak voor dit soort raadsels ontwikkelen. We doen dat aan de hand van een net ontdekte Zuid-Afrikaanse mensensoort. Show less
We develop a framework to differentiate the technological niches of co-existing hominin species by reviewing some theoretical biases influential in thinking about techno-behaviours of extinct... Show moreWe develop a framework to differentiate the technological niches of co-existing hominin species by reviewing some theoretical biases influential in thinking about techno-behaviours of extinct hominins, such as a teleological bias in discussing technological evolution. We suggest that some stone-tool classification systems underestimate technological variability, while overestimating the complexity of the behaviours most commonly represented. To model the likely technological niches of extinct populations, we combine ecological principles (i.e. competitive exclusion) with physical anthropology and the archaeological record. We test the framework by applying it to the co-existence of Homo naledi and Homo sapiens during the late Middle Pleistocene in southern Africa. Based on our analysis, we suggest that tool use was probably not an essential part of H. naledi’s niche, but that technology occasionally provided caloric benefits. In contrast, tool use was a structural part of the H. sapiens way of life. We provide reasoning for our interpretation that the latter population is associated with more sophisticated reduction strategies and the development of prepared core technology. The method also has applicability to cases such as the co-existence of different toolmakers during the Earlier Stone Age (ESA) in East Africa and the co-existence of Neanderthals and H. sapiens in Eurasia. Show less
Om te achterhalen waarom mensen miniatuur-werktuigen gaan maken tijdens de laatste ijstijd, onderzocht ik een vindplaats uit Lesotho met Dr. Justin Pargeter, hoofd van het African Palaeosciences... Show moreOm te achterhalen waarom mensen miniatuur-werktuigen gaan maken tijdens de laatste ijstijd, onderzocht ik een vindplaats uit Lesotho met Dr. Justin Pargeter, hoofd van het African Palaeosciences Laboratorium aan New York University. Wij laten zien dat de technologische ontwikkeling leidt tot grotere efficiëntie in de productie van cutting edge (snijrand). Deze innovatie valt grofweg samen met een uitbreiding van het menu. De ontwikkelingen in het dieet en in de technologie lopen niet perfect parallel. Er zijn dus nog meer factoren in het spel. Show less
