AcaWiki - User contributions [en]

A 3D morphometric analysis of surface geometry in Levallois cores: patterns of stability and variability across regions and their implications

2014-11-08T05:44:06Z

Loracon: Created page with "{{Summary |title=A 3D morphometric analysis of surface geometry in Levallois cores: patterns of stability and variability across regions and their implications |authors=S.J. L..."

{{Summary
|title=A 3D morphometric analysis of surface geometry in Levallois cores: patterns of stability and variability across regions and their implications
|authors=S.J. Lycett, N. von Cramon-Taubadel
|url=http://www.sciencedirect.com/science/article/pii/S030544031200492X
|tags=stone, lithic, Middle Paleolithic, Levallois, cores, Africa, Europe, Near East, India, language, platform, variability, cultural transmission, learning, stability
|summary=Are there significant morphological differences in Levallois cores? Are these differences variable by region? Are these differences observable only on the planform or are they apparent on the flake producing surface? What do these variances and/or stabilities indicate about cultural transmission of the Levallois technology? What insight does this cultural transmission give into Levallois producing hominins?
In order to address these issues, Lycett and Cramon-Taubadel analyzed Levallois cores from nine locations spanning Africa, Europe, the Near East, and India.

They limited their analysis to preferential Levallois cores and analyzed these using geometric morphometrics, whereby particular landmarks were mapped out using 3D image capturing to determine the shape of each artifact. This created a means to compare various cores using quantifiable means. They then proceeded to use generalized Procrustes analysis to factor out the affects of size, leaving only the geometric shape for comparison. Fifty-one 3D coordinates, also known as ‘semilandmarks,’ were measured on each core with a Crossbeam Co-ordinate Caliper to obtain these shapes.

As hypothesized, Lycett and Cramon-Taubadel found that the flake production surface of the cores was rather uniform, while the planform showed some variation.

|relevance=This analysis displays that there is remarkable similarity in the form of the flaking surface for Levallois cores. Producing such standardized, complicated flake production surfaces indicates that some sort of teaching method may well have been involved. It would follow that in order for teaching to occur, language may have played a role. This is relevant to larger debates revolving around which hominins had language and when, most notably regarding the Neanderthals associated with Levallois technology.

While it is evident that some sort of higher cognitive processes were involved in the production of such standardized Levallois cores, it is problematic to infer language based off of that alone. While language could have been an important component in cultural transmission, learning can also occur without language, as evidenced in other species. The authors are careful to note that while language would certainly have been helpful, the case is not definitive. Certainly one can imagine that such a hands on procedure, even a complicated one, could have been transmitted via gestures and visual learning. That’s not to say that language did not play a part, just that we may not ever really know.
|journal=Journal of Archaeological Science 40(3):1508–1517
|pub_date=2013
}}

Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge

2014-11-08T05:34:01Z

Loracon:

{{Summary
|title=Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge
|authors=Y. Kimura
|url=http://www.sciencedirect.com/science/article/pii/S0047248402905762
|tags=Oldowan, Acheulian, Olduvai Gorge, Koobi Fora, pre-Oldowan, Homo ergaster, Developed Oldowan A, Developed Oldowan B, raw material, stone, artifact
|summary=What can a reexamination of Oldowan and Acheulian technologies in Beds I and II at Olduvai Gorge tell us about trends through time? How do these trends fit into trends in the surrounding area? How can these trends be applied to models of possible changes experienced by Homo ergaster? In this review, nine sites at Olduvai Gorge from Bed I and II will be examined. Some sites in the surrounding area of Koobi Fora and “pre-Oldowan” sites were also mentioned.

Bed I Oldowan
 1.87 to 1.75 m.y.a.
 sites: DK and FLK Zinjanthropus

Bed II DOA (Developed Oldowan A)
 1.65 to 1.53 m.y.a.
 sites: HWK East levels 3 and 4, FLK North sandy conglomerate, MNK chert factory site

Bed II DOB (Developed Oldowan B) and Acheulian
 1.53 to 1.2 m.y.a.
 Acheulian site: EFHR
 DOB sites: FC West and TK Upper Floor

Koobi Fora
 1.88 to 0.7 m.y.a.
 KBS and Karari Industries

Kimura focused on the trends between Bed I and II at Olduvai Gorge. The variables she chose were raw materials and artifact composition, size of flakes, shape of flakes, weight of cores, the number of scars on an artifact, the flake recovery rate, the type of flake, the occurrence of a bifacial edge, the prevalence of hinged flakes, and the prevalence of battered artifacts.

The raw materials consisted of lava (1,989), quartz (9534), and chert (2,329). The artifact composition was comprised of cores, flakes, and utilized materials.

The raw material was obtained from the nearest available source. Chert was only available from 1.65 to 1.53 m.y.a. DOA assemblages were quite different than the other assemblages. Retouched flakes only occurred at a high rate during DOA, which is attributable to chert use. The flake size was shown to increase with time. Side-struck flakes occurred more at the Acheulian site of EFHR. The core weight was shown to relate to raw materials with a trend toward increasing core weight. This, along with the number of scars, indicated an increased ability through time to handle larger raw materials after 1.5 m.y.a. There appeared to be increased transport during the DOA. The flake recovery rate indicates core transport and differing stages of reduction at different sites for chert. The flake type showed a chronological trend in the composition of lava flakes. The bifacial edge presence and length increase after 1.5 m.y.a. Hinged terminations occur more with chert. Signs of battering on artifacts increases through time.

A significant change took place between Bed I and II at around 1.5 m.y.a. Flake size increased, bifacial edges were present more and their length increased, and signs of battering on artifacts increased. The implications of these changes are that hominids became better tool makers, used tools more, and apparently transported tools more.

At Koobi Fora lava is the dominant material. There is a prevalence of core scrapers and other differences between here and the Olduvai Gorge Bed I and II. Larger flakes also appear here at around 1.5 m.y.a.
|relevance=Raw material appears to play a huge factor in many of the variables analyzed. Perceived technological changes in many instances are shown to have a strong correlation with the raw material used. This is most apparent during the DOA when chert was available. Previous explanations may need to be reconsidered in light of this observation. Overall, the variables indicate a change taking place at about 1.5 m.y.a. at Olduvai Gorge. The implications are that hominids of this time were better tool makers, used tools more, and appeared to transport tools more after this pivotal point in time. The Acheulian industry also appears to share many characteristics with the contemporaneous DOB. Koobi Fora also indicates both regional variation and region wide trends.

The observations observed through the analysis of the selected variables provide valid and significant insights. The extrapolation of these insights to earlier tool production starting at 2.5 m.y.a., however, seems unfounded. While there is evidence that the Oldowan technology remained static over a long period of time, it seems that the evidence presented by the author is not sufficient to support his speculations regarding Homo ergaster prior to the time period of the sites examined in this paper. An extensive review of the 2.5 m.y.a. and 2.3 m.y.a. sites mentioned would have provided more relevant support for the author’s position.
|journal=Journal of Human Evolution 43: 2921-321.
|pub_date=2002
|subject=Anthropology
}}

Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge

2014-11-08T05:31:34Z

Loracon: Created page with "{{Summary |title=Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge |authors=Y. Kimura |url=http://www.sciencedirect.com/science/article/pii/S0047..."

{{Summary
|title=Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge
|authors=Y. Kimura
|url=http://www.sciencedirect.com/science/article/pii/S0047248402905762
|tags=Oldowan, Acheulian, Olduvai Gorge, Koobi Fora, pre-Oldowan, Homo ergaster, Developed Oldowan A, Developed Oldowan B, raw material, stone, artifact
|summary=What can a reexamination of Oldowan and Acheulian technologies in Beds I and II at Olduvai Gorge tell us about trends through time? How do these trends fit into trends in the surrounding area? How can these trends be applied to models of possible changes experienced by Homo ergaster? In this review, nine sites at Olduvai Gorge from Bed I and II will be examined. Some sites in the surrounding area of Koobi Fora and “pre-Oldowan” sites were also mentioned.

Bed I Oldowan
1.87 to 1.75 m.y.a.
sites: DK and FLK Zinjanthropus

Bed II DOA (Developed Oldowan A)
1.65 to 1.53 m.y.a.
sites: HWK East levels 3 and 4, FLK North sandy conglomerate, MNK chert factory site

Bed II DOB (Developed Oldowan B) and Acheulian
1.53 to 1.2 m.y.a.
Acheulian site: EFHR
DOB sites: FC West and TK Upper Floor

Koobi Fora
1.88 to 0.7 m.y.a.
KBS and Karari Industries

Kimura focused on the trends between Bed I and II at Olduvai Gorge. The variables she chose were raw materials and artifact composition, size of flakes, shape of flakes, weight of cores, the number of scars on an artifact, the flake recovery rate, the type of flake, the occurrence of a bifacial edge, the prevalence of hinged flakes, and the prevalence of battered artifacts.

The raw materials consisted of lava (1,989), quartz (9534), and chert (2,329). The artifact composition was comprised of cores, flakes, and utilized materials.

The raw material was obtained from the nearest available source. Chert was only available from 1.65 to 1.53 m.y.a. DOA assemblages were quite different than the other assemblages. Retouched flakes only occurred at a high rate during DOA, which is attributable to chert use. The flake size was shown to increase with time. Side-struck flakes occurred more at the Acheulian site of EFHR. The core weight was shown to relate to raw materials with a trend toward increasing core weight. This, along with the number of scars, indicated an increased ability through time to handle larger raw materials after 1.5 m.y.a. There appeared to be increased transport during the DOA. The flake recovery rate indicates core transport and differing stages of reduction at different sites for chert. The flake type showed a chronological trend in the composition of lava flakes. The bifacial edge presence and length increase after 1.5 m.y.a. Hinged terminations occur more with chert. Signs of battering on artifacts increases through time.

A significant change took place between Bed I and II at around 1.5 m.y.a. Flake size increased, bifacial edges were present more and their length increased, and signs of battering on artifacts increased. The implications of these changes are that hominids became better tool makers, used tools more, and apparently transported tools more.

At Koobi Fora lava is the dominant material. There is a prevalence of core scrapers and other differences between here and the Olduvai Gorge Bed I and II. Larger flakes also appear here at around 1.5 m.y.a.
|relevance=Raw material appears to play a huge factor in many of the variables analyzed. Perceived technological changes in many instances are shown to have a strong correlation with the raw material used. This is most apparent during the DOA when chert was available. Previous explanations may need to be reconsidered in light of this observation. Overall, the variables indicate a change taking place at about 1.5 m.y.a. at Olduvai Gorge. The implications are that hominids of this time were better tool makers, used tools more, and appeared to transport tools more after this pivotal point in time. The Acheulian industry also appears to share many characteristics with the contemporaneous DOB. Koobi Fora also indicates both regional variation and region wide trends.

The observations observed through the analysis of the selected variables provide valid and significant insights. The extrapolation of these insights to earlier tool production starting at 2.5 m.y.a., however, seems unfounded. While there is evidence that the Oldowan technology remained static over a long period of time, it seems that the evidence presented by the author is not sufficient to support his speculations regarding Homo ergaster prior to the time period of the sites examined in this paper. An extensive review of the 2.5 m.y.a. and 2.3 m.y.a. sites mentioned would have provided more relevant support for the author’s position.
|journal=Journal of Human Evolution 43: 2921-321.
|pub_date=2002
|subject=Anthropology
}}

Abrupt Terminations and stone artefact reduction potential

2014-11-08T05:15:53Z

Loracon: Created page with "{{Summary |title=Abrupt Terminations and stone artefact reduction potential |authors=O.J. Macgregor |tags=terminations, experiment, lithic, reduction, stone, artifact, artefac..."

{{Summary
|title=Abrupt Terminations and stone artefact reduction potential
|authors=O.J. Macgregor
|tags=terminations, experiment, lithic, reduction, stone, artifact, artefact, glass core, scar, removal
|summary=What reduction methods help to preserve raw material? What might one look for in the archaeological record to suggest an effort to preserve raw material? In particular, what role do abruptly terminated flake scars play in all of this? If abruptly terminated flake scars are detrimental to an ability to reduce a core, what strategies might be implemented to overcome this? In order to investigate these questions, Macgregor decided to perform experiments aimed at an effort to see what it takes to overcome the flake scar issue.

Macgregor dropped ball bearings onto glass cores that had varying artificial termination scars carved into them in order to determine the effect that platform angles and platform thickness have on overcoming the flake scar issue. He controlled for all other variables.
He used eight different categories of cores in order to perform his analysis. Four of the cores had exterior platform angles of 70 degrees, while the other four had angles of 45 degrees. Within each angle category, the cores were divided into categories based on the type of abruptly terminated flake scar that was carved into them. The first category consisted of cores without a flake scar. The second category had a scar 5mm deep and 20mm long. The third category had a scar 10mm deep and 20mm long. The fourth category had a scar 5mm deep and 40mm long. The platform thickness varied from a little over 2mm to almost 14mm.

Macgregor determined two important thresholds, which he defines as the “detachment threshold” and the “scar threshold”. The detachment threshold is defined as the point when the platform became too thick to be able to remove a flake with the force used. The scar threshold is defined as the point at which the platform is thick enough to allow a fracture that fully removed the scar. The range of platform thicknesses between the two thresholds is the important factor as it determines how difficult it is to overcome the issue of the scar.
Macgregor found that the range of platform thicknesses was greater for the 45 degree cores. Also, while lengthening the scar on the 70 degree cores significantly reduces the region between the two thresholds, doing so on the 45 degree cores does not decrease the range. He thus concludes that the higher the exterior platform angle, the more issues one would have with abruptly terminated flake scars.
|relevance=This article is relevant to theories that relate changes in artifact types to changes in the costs associated with the material used for stone artifacts. It relates what one might look for in the archaeological record to suggest such high costs.

While Magregor’s experiment is quite convincing in its assertion that higher exterior platform angles are more problematic for trying to recover a core from a flake scar, I am not sure that he fully connects this contention to what one might find in the archaeological record. I was a little confused about whether edge angles were the same thing as exterior platform angles, making some of Magregor’s discussion at the end difficult to associate with his experiments. When he spoke of using multiple platforms to overcome the issue of flake scars it seemed unrelated to his experiments and therefore a little distracting. While his points in the discussion at the end may be true, I would have preferred if he had focused more on the direct implications of his own particular experiment and its outcomes. That being said, I do believe that the experiments Macgregor conducted and their results are an important contribution to the understanding of reduction processes and their connection to the cost of raw materials.
|journal=In Clarkson, C. and L. Lamb (Eds) 2005 Lithics ‘Down Under’: Australian Approaches to Lithic Reduction, Use and Classification. British Archaeological Reports International Monograph Series S1408. Oxford: Archaeopress.
|pub_date=2005
|subject=Anthropology
}}

What attributes are important for the measurement of assemblage reduction intensity? Results from an experimental stone artefact assemblage with relevance to the Hoabinhian of mainland Southeast Asia

2014-10-08T19:13:25Z

Loracon: Created page with "{{Summary |title=What attributes are important for the measurement of assemblage reduction intensity? Results from an experimental stone artefact assemblage with relevance to..."

{{Summary
|title=What attributes are important for the measurement of assemblage reduction intensity? Results from an experimental stone artefact assemblage with relevance to the Hoabinhian of mainland Southeast Asia
|authors=Ben Marwick
|url=http://www.sciencedirect.com/science/article/pii/S0305440307001653
|tags=reduction intensity, attributes, Hoabinhian, stone, artefact, assemblage, Southeast Asia, experiment, dorsal cortex location
|summary=Marwick analyzes what attributes one can look for to help make sense of Hoabinhian lithic assemblages. In particular, he focuses on how the attributes relate to the intensity of reduction. He then goes on to consider how these may relate to issues surrounding mobility, resource availability, and other such questions. He analyzes what methods might be useful for acquiring data that relates to the larger, overarching questions. Examples are how Hoabinhian assemblages contribute to our understanding of foraging in a tropical forest, how geographically spread the technology was, or how related to the domestication process and associated changes it is.

In order to address these questions, Marwick takes an experimental approach where he attempts to recreate Hoabinhian-like assemblages to take measurements on throughout the reduction process. This approach was undertaken due to a lack of useful methods for analyzing the Hoabinhian assemblages, which tend to have few retouched flakes and little to no unique artifact forms. He advocates for a new way of analyzing these assemblages, as previous studies have focused on typology rather than interpretation. The goals of the analysis are to discover how flake variables are affected through the process of core reduction and then to determine what are the best variables to use for answering archaeological questions.

The experimental method involved recording 28 variables from flakes that were obtained by hard hammered percussion from 30 river cobbles. There was an attempt made to simulate a ‘typical’ Hoabinhian assemblage consisting of sumatraliths, short axes, choppers, and other unifacially flaked cobbles. The flakes were given a ranked intensity of reduction on a scale of one to ten, with one being the first reduction phase. In total, there were 625 flakes and 159 non-flakes.

The results indicate that there is not a significant change in flake mass associated with the level of reduction. Additionally, overhang removal was strongly correlated with an increased level of core reduction. The interior platform angle and level of reduction were also strongly correlated. The overhang removal and interior platform angle seem to be connected. The percentage of dorsal cortex is also strongly linked to the level of cobble reduction. It works best as a sign of early reduction. The amount of dorsal flake scars is significantly related to the amount of reduction, but can be less relied upon as a sign of reduction level than the other listed variables. A new method, which analyzes the dorsal cortex location is proposed. The dorsal cortex location is directly linked to intensity of reduction. It appears to be independent of flake size. There are four classifications that are identified. These are the primary, crescent, distal and tertiary. With this approach, the inter-observer error has been shown to be low and may approach zero when trained lithic analysts use the method. The distal cortex class can be further analyzed to provide even more resolution on the reduction process, especially in the later stages. When analyzing a core after the reduction process has been completed, the number of flake scars does not relate to the number of flakes removed. Cortex ratio seems to be a good indication of reduction intensity.

|relevance=This experiment is likely to have application to non Hoabinhian assemblages. More experiments should be undertaken to see how these methods, in particular the new method of dorsal cortex location, and variables compare to other types of assemblages. Further studies should be conducted to explore how these experimental findings can be applied to the interpretation of actual Hoabinhian assemblages, especially when considering 'big picture' questions.
|journal=Journal of Archaeological Science 35: 1189-1200
|pub_date=2008
|subject=Anthropology
}}

How to write a scientific masterpiece

2014-09-29T13:53:24Z

Loracon: Created page with "{{Summary |title=How to write a scientific masterpiece |authors=Ushma S. Neill |url=http://www.jci.org/articles/view/34288 |tags=article, journal, writing, publication |summar..."

{{Summary
|title=How to write a scientific masterpiece
|authors=Ushma S. Neill
|url=http://www.jci.org/articles/view/34288
|tags=article, journal, writing, publication
|summary=Neill’s article “How to write a scientific masterpiece” is a detailed account of what to do and not to do when writing scientific literature for publication. She begins by describing what one should do even before they begin to write the paper. Namely, she suggests that one chooses carefully which publication to submit to, making sure that it is one appropriate to their work. Next, she goes into issues surrounding authorship. Then she goes on to discuss the significance of having a well written cover letter. It should be about four to five paragraphs, with an introduction to the research and who the authors are and why the research is significant. As she stresses, the cover letter should be addressed to the journal you are submitting to. Along with this, the paper should be formatted based off the guidelines that the journal sets forth. Moving on to writing the actual article, Neill expresses that it is important to pick a relevant title that is about 15 words long and does not contain jargon. The abstract needs to be easily accessible to readers, interesting, and not too in depth. The formula for this is to start with a couple of sentences to give the general overview, move on to the relevant discoveries, and to finish with a couple of sentences listing the significance of the work. As for the results, Neill relates that not every step taken needs to be included in the paper. The results should be presented in either chronological order or with the most important one listed first. Also, one should make use of the supplemental data section if needed, as having too many results can cause distraction. Moving on to the discussion, one should start with a recap of the research and list the implications of that research. The discussion should be an interpretation of the research and conclusions drawn from it that lead back to one’s hypothesis. The introduction is a place where one can present one’s hypothesis along with some background information in the particular field that leads up to one’s own research. It should also include a description of what one is about to demonstrate. The methods should be described so that a reader could theoretically replicate your procedures. As far as figures go, they should have concise and descriptive legends and be formatted in a way that makes them easy to read. Moving on to other things that one must consider, Neill goes into detail about the peer review process along with the decision, revision, and appeal processes. She notes that one should be polite when addressing the journal one is submitting to. Overall, Neill gives an in depth, step by step account of the publishing process and what steps to take to ensure that one has the best chance at succeeding at getting published.
|journal=The Journal of Clinical Investigation 117(12)
|pub_date=2007
}}