Quartile 3 comprises the 50 th to 75 th percentile of the sample by volume. Our analysis revealed no clear patterns. There are many several possible reasons for this.
First, we posit that despite our efforts to refine our sample, core cross sections as defined in this study were heavily influenced by largely non-cultural factors such as raw material quality and availability Andrefsky ; Inizan et al.
Lithic technology is reductive in nature, and mistakes can be difficult to correct. A single errant removal or the location of inclusions or fissures within a nodule can dramatically change core morphology. These factors can force a knapper to abandon a core. It is possible that for our sample, issues arising at the end of the reduction sequence were greater influences on core cross section shape than cultural norms of production.
Although the cross section shape of Paleolithic blade cores is likely the result of culturally and functionally mediated manufacturing traditions, these pressures are arguably much stronger on artifacts such as bifaces and projectile points. There is evidence that these types of objects can serve a culturally communicative purpose Wiessner In many cases, cores are also a byproduct of manufacture, rather than the target of production.
The shape of artifacts that are used as tools are more likely to be constrained based on their function. For example, points arguably must be a certain shape and size to effectively serve as projectile tips Thomas As a result, it is perhaps then not surprising that most successful applications of EFA in lithic analysis have looked at the shape of these artifact types.
Finally, it is also possible there is simply too much natural variation in core cross section shape to make EFA an effective approach to quantitatively investigating similarities and differences in the volumetric approaches of Paleolithic knappers. Analyses of flake scar orientation e. Bretzke and Conard ; Clarkson et al.
The axis of symmetry is defined as the axis about which the core is most symmetrical when viewed from above with the platform facing up.
The retreat axis is the axis perpendicular to a vector defined by the greatest extents of the flaking surface when the core is viewed from above Figure 2.
Based on qualitative observations, Roussel et al. In contrast, it is argued that the angle between these axes should be more oblique i. Once again, our goal with this analysis was to determine if existing qualitative observations could be confirmed quantitatively.
This analysis utilizes the same black and white platform cross section images obtained for the previous analysis section 4.
Additionally, we used a similar Geomagic-to-Photoshop workflow to obtain cross section images of the entire core as viewed from above. We captured these full core screenshots simultaneously with the platform data to ensure both images were taken from the same perspective and at the same scale. Next, we brought both images into ImageJ Schneider et al.
We used a macro to draw a vertical line through the center of the platform cross section. This macro works by splitting a selection into equal portions by area Vischer We then used the built-in ImageJ macro DrawEllipse to overlay a best-fit ellipse and the major and semi-major axes of this ellipse over the image of the full core. The angle measurement function of ImageJ was then used to measure the angle between the vertical line through the platform cross section and the nearest axis of the best-fit ellipse Figure Image exported from ImageJ using the workflow described in section 4.
The measured angle between core axes is marked in yellow. Results of the analysis of the angle between core axes: a Distribution of the raw data; b Box plot comparing data from the three different assemblages. The black circle represents the assemblage mean. While our initial findings support this hypothesis to some extent, for the time being we believe it is safer to view these results with caution. We concluded that it was more scientifically conservative not to exclude these artifacts from our statistical analysis.
This is because we do not believe our sample size gives us the ability to determine if these specimens are indeed outliers, or if our particular sample did not capture the full range of variation of Protoaurignacian cores.
While these results could be used to support our initial hypothesis, we would advocate running this analysis on a larger sample of artifacts from more sites before making any definitive archaeological conclusions. This study had multiple goals. This leads to our second aim: to explore ways of quantitatively investigating archaeological hypotheses derived from primarily qualitative study.
This study demonstrates that while digital quantitative analyses can support qualitative or traditional observations, the application of these techniques is not guaranteed to produce significant results. To untangle these possibilities, we see several paths forward. A first step would be to increase sample size, ideally incorporating artifact data from additional assemblages and sites. We hope that a trend towards openly publishing 3D artifact models, as we are doing with this paper, will make it easier for researchers in the future to access larger and more diverse datasets.
Next, we would advocate more methodological experimentation and the publication of results, especially those that are negative or ambiguous. New ideas only become established methodologies through testing, adaptation, and iteration. These processes are most successful when undertaken as a community. We emphasize that although this research was quantitative in nature, we are not advocating the point of view that quantitative analyses are inherently superior to qualitative observations, although we do recognize certain quantitative variables are more straightforward to collect in an objective manner.
Both types of analysis can inform one another. Quantitative approaches can help researchers make their definitions of qualitative variables more explicit, and thus more reproducible.
Above all, results of any type of study should always be interpreted within their greater archaeological context, and these interpretations should remain in conversation with anthropological theory and our understanding of human behavior. Despite the cautious tone of this paper, we are nothing but optimistic about the future of computers and the application of digital techniques in lithic analysis. We contend that inconclusive results should not be seen as methodological setbacks, but as first steps into a larger world.
We thank the site owner, J. This research was made possible by a grant from the Leakey Foundation. Digital preservation and dissemination of ancient lithic technology with modern micro-CT. Computers and Graphics , 35 4 : — Andrefsky, W. Raw-Material Availability and the Organization of Technology. American Antiquity , 59 1 : 21— A geometric morphometric relationship predicts stone flake shape and size variability.
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PloS One , 6 12 : e The handaxe reloaded: A morphometric reassessment of Acheulian and Middle Paleolithic handaxes. Some personal ornaments have been found at these sites, some of which are stained with red ochre: all of these are evidence of what archaeologists call modern human behaviors or behavioral complexity. The stone tools led to the assumption of cultural continuity, with some scholars well into the s arguing that humans in Europe had evolved from Neanderthals. Subsequent archaeological and DNA research has overwhelmingly indicated that early modern humans in fact evolved in Africa, and then migrated into Europe and mixed with the Neanderthal natives.
The parallel discoveries of bone tools and other behavioral modernity at Chatelperronian and Aurignacian sites, not to mention radiocarbon dating evidence has led to a realignment of the early Upper Paleolithic sequence.
When and how that happened--when the African emigrants turned up in Europe and when and how the Europeans learned to make bone tools and backed scrapers--is a matter for some debate. Did the Neanderthals imitate or learn from or borrow from the Africans when they began using sophisticated stone and bone tools; or were they innovators, who happened to learn the technique about the same time? Archaeological evidence at sites such as Kostenki in Russia and Grotta del Cavallo in Italy has pushed back the arrival of early modern humans to about 45, years ago.
They used a sophisticated tool kit, complete with bone and antler tools and personal decorative objects, called collectively Aurignacian. Evidence is also strong that Neanderthals first appeared in Europe about , years ago, and they relied on primarily stone tools; but about 40, years ago, they may have adopted or invented bone and antler tools and personal decorative items.
Whether that was separate invention or borrowing remains to be determined. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. October 30, The new high precision dates show that the CP bone tools and body ornaments were produced by Neanderthals.
However since these late Neanderthals only manufactured CP body ornaments after modern humans arrived in neighboring regions, the study suggests that cultural diffusion might have taken place between modern humans and Neanderthals. The so called "transitional industries" are a key for understanding the replacement process of Neanderthals by modern humans in western Eurasia at the beginning of the Upper Paleolithic between 50, and 40, years ago.
However at the Grotte du Renne, CP layers also produced rather sophisticated bone tools and body ornaments. Despite this fossil evidence the question of whether Neanderthals could manufacture such sophisticated objects is the topic of intense debate. Some have proposed that the admixture of artifacts between different layers could explain this association.
Hublin's research team selected 40 well-preserved bone samples from the Grotte du Renne, primarily from those areas that contained CP body ornaments or Neanderthal remains but also from the underlying older Mousterian and younger Protoaurignacian layers.
The researchers extracted collagen from the samples and dated the bones by taking isotopic measurements. Using an accelerator mass spectrometer the researchers obtained very high precision 14C dates.
At the Grotte du Renne, the large series of dates obtained prove that no major layer admixture occurred in the site. This confirms that Neanderthal populations are directly responsible for the production of CP assemblages in central France, including the body ornaments of Arcy. Most likely, some level of cultural diffusion occurred from one group to the other more than 40, years ago.
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