Wednesday, October 31, 2012

So What's the Deal with the Neanderthal, Their Demise?

Were contemporary modern humans, you know—the species that lives on to this day, responsible? Or did everything else that was working fine for the Neanderthals' survival, prior to the arrival of the so-called anatomically modern humans, came to a halt for some reason or another?

Introduction: 

The discovery of  Neanderthal remains [see the entry: How are the Media and Schools catching up with Scientific Progress? Pt.4] has naturally raised the curiosity of people, because they seem so close to us humans, and so, many inquiring minds want to know what happened to these extinct human cousins. Preexisting evidence so far only presents sketchy explanations of not only exactly how they (Neanderthals) reached their extinction, but also precisely where and from what ancestral line [although there are guesses as to what that might be] Neanderthals emerged. Notwithstanding significant strides made in the discipline of molecular genetics, as well as new findings in human paleontological record, researchers are still battling out the search for the most solid and parsimonious answers to those main aforementioned fronts.

Where the demise of the Neanderthal is concerned, there have been suspicions of the role of modern humans in this within the scientific community for a while now, although there seemed to be an air of reluctance to want to explore that very possibility. To that end, the more popular narratives which have circulated the web for years, generally looked mostly to abrupt environmental shifts as the prime suspect in the demise of the Neanderthals, purportedly in accompaniment with the insufficient resourcefulness of the Neanderthal; the role of modern humans had generally taken somewhat of a back seat in such narratives.

Discussion: 

The role of humans in the Neanderthal's demise now seems to be gaining more acceptance. This trend can be seen in such presentations like the TV documentary titled "Clash of The Cavemen", 2008. The challenge has generally been that of coming up with solid evidence for what could have possibly given modern humans advantage over their Neanderthal counterparts, in a region to which the Neanderthals were at the time, very likely, more physically adapted than modern humans, and evidence for contact between Neanderthals and modern humans, while reconstructing the most plausible scenario in which modern humans would essentially replace Neanderthals.

Some observers have figured that so-called anatomically modern humans did not make that much of a technological leap over the Neanderthals at the time the former (modern humans) emerged in the Neanderthal's neighborhood.Coming from such perspectives, attributing the fate of Neanderthals to the ingenuity of their 'anatomically modern' human counterparts would then amount to ascribing undue credit to the latter's creativity. Perhaps, it may well be argued that the technological disparity between anatomically modern humans and Neanderthals was not spectacular, but on occasion, even the slightest of difference can be enough to determine who or what gets an advantage in a situation at hand. Predictably enough, the temptation of comparing Neanderthal tools and weaponry against those of the anatomically modern human counterparts (who were personified as the "Cro-Magnons" in this case) could not be escaped in Clash of The Cavemen, which was mentioned earlier.

What makes Clash of The Cavemen a useful pick, when citing documentary releases for the purpose of the ongoing discussion, is that its material content takes on a quintessential form, in terms of the direction which increasingly typifies discourse on Neanderthal—i.e. the surfacing of the sort of topics, along with corresponding controversies, that have come to dominate the quest to unravel what happened to these long gone human species.

As hinted to in the opening notes of this entry, while Neanderthals fascinate many within paleontological circles, the type has often been inflicted with typecasting and bias characterized by a paradoxical twist, whereby the type has in many cases, been typecasted as a relatively unsophisticated brutish cave-dwelling creature, but at the same time anointed as the "true" ancestor of certain "Eurasians", mainly by White nationalists/racialists and strong opponents of the Out Of Africa (OOA) recent origins of contemporary humans. Such prejudice lingers, but there are signs of some loosening of its extent.

Take for instance, that aforementioned surfacing and/or better amplification of voices within academia, which now place Neanderthals and their anatomically modern human contemporaries on nearly equal footing, as far as intellectual/technological creativity went. Accordingly, some have embraced the idea that Neanderthal creativity was "different", but not inferior! A subset of such observers have even taken it a step further, by suggesting that Neanderthal tools/weapons were even superior to those of the "anatomically modern" counterparts; one of the traits such advocates point to, in favor of the Neanderthal workmanship, is the reportedly greater robusticity which characterized their cutlery and stone-points of  such weaponry like spears.

Be that as it may, it is hard to make a case for a superior craftsmanship on the part of the Neanderthals, on the weapons front, particularly when it is eventually also conceded that such weaponry would have had its limitations in open spaces. For example, it is widely acknowledged within research circles, that the Neanderthals were neither avid nor adept users of projectiles; rather, they were heavy users of thrusting-spears, which they applied in ambushing and close-quarters hunting. Many reckon that such hunting tactics may have worked well in heavily-wooded areas. Not so, in wide open spaces, which one would have to take it, that Neanderthals eventually found themselves, at some point in their waning days, as a species. 

Projectiles on the other hand, while expected to involve lighter material [hence, less robust vis-a-vis the heavier counterparts applied by Neanderthals], would have been reasonably effective in heavily-wooded and open spaces alike. It has been estimated that the "anatomically modern" counterparts of Neanderthals had projectiles within their arsenals, something which they picked up from the ecological home of "anatomically modern" humans, i.e. Africa, where humans would have graduated to usage of projectiles some time before colonizing other landmasses.

Osteological indicators of these contrasting endeavors between Neanderthals and their "anatomically modern" counterparts, according to the narrative in Clash of The Cavemen, have manifested in "trauma sustained, especially in the cranium...broken fingers, broken forearms" and "fractures to the collarbone" of Neanderthal specimens, while "anatomically modern" counterparts were inflicted with "less common fractures of the arms, less common fractures of the scapula, of the rib cage."

As noted several times earlier, more voices within academic circles have come out of the woodwork in recent times, paying a bit more respect towards the Neanderthal, than was the case in earlier times. In tandem with this development, more observers have come to entertain the prospect of not placing anatomically modern human contemporaries of Neanderthals on a relatively higher intellectual level. There is even an understanding within research circles, that anatomically modern humans appear to have used similar or equivalent tools to those applied by Neanderthals for a fairly considerable amount of time. So then, how did the shift towards heavy use of projectile weaponry by 'anatomically modern' humans come about?

Well, as hinted earlier, there is a loud segment of anthropologists which puts forward the case that this behavioral pattern (heavy use of projectile weaponry) had its precedence on the African continent, before it eventually spread to other parts of the globe, along with the spread of 'anatomically modern' humans. Projectile use in Africa has been traced back to the Middle Stone Age (MSA). There is an openness to the prospect of projectile points [mainly stone] appearing in the African record prior to 50ky ago, while possible candidates of such in the so-called "Near East" and in Europe are "placed after the Middle/Upper Paleolithic transition, ca 35-45ky ago" (Shea, 2006).

Classifying prehistoric armature into projectiles has not been without its own share of controversy, however. John Shea of the Stony Brook University, for example, points out that while most archaeologists have reached common ground in terms of the prospect of "clear and convincing evidence" for projectile technology being "present in Eurasian Upper Paleolithic and the African Later Stone Age", and rejecting the qualification of hand-axes and spheroids as projectiles, views have been divided on the candidacy of other prehistoric entries in projectile technology. As Shea articulates it,...

European researchers have generally regarded claims of European MP (Middle Paleolithic) projectile weapon armatures with skepticism (Anderson-Gerfaud, 1990; Bordes,1961; Debénath and Dibble, 1994; Holdaway, 1989; Kuhn and Stiner, 2001; Plisson and Béyries, 1998). The usual candidates for European MP projectile points are Levallois points, Mousterian points, and foliate bifaces (the latter mainly from Central and Eastern Europe). Such points are usually described as being too large to have been projectile points, lacking obvious modification for hafting, and not showing characteristic impact breakage and allied wear traces.

One other weaponry that has for instance, been described as featuring points that are "too large to have been projectile points", are the wooden spears from Schöningen in Germany. Here too, while some have reportedly identified these spears as "javelins" (Rieder, 2003; Theime, 2000), others have determined that the tips or points of these weaponry are much larger than those of "ethnographic throwing spears" of control samples (Shea, 2006). Shea adds the following caveat:

Even if they are accepted as throwing spears on the basis of replicative experiments, their effective range (their users’ “lethal radius”) is likely to have been smaller than that of ethnographic projectile weaponry.

With respect to reservations about European MP specimens and other controversies surrounding the identification and classification of certain specimens as projectiles, Shea continues as follows:

Nor to they displaying the patterned chronological and regional variation seen among stone projectile points of recent human hunter-gatherers. Mousterian and Levallois points tend to be rare among European MP assemblages. An additional subjective factor underlying European prehistorians' views about MP projectile weapons is a longstanding tradition of viewing Neandertals' behavioral capacities as significantly inferior to those of recent Homo sapiens (Trinkaus and Shipman, 1993).

On the other hand...

Historically, Africanist researchers have been more receptive to hypotheses about MSA projectile point technology. Many African MSA points in question are light, thin, and narrow, heavily retouched, often feature basal modification congruent with hafting, and display both chronological and regional variation (Clark, 1988; Leakey, 1960; McBrearty and Brooks, 2000). Pointed artifacts are relatively common among MSA assemblages, particularly those dating to less than 100 Ka (Brooks, et al., 2005; McBrearty and Brooks, 2000). The willingness of Africanists to credit MSA humans with projectile technology, too, may have a subjective dimension. The bow and arrow remains in widespread use in Subsaharan Africa, and there is a long history in Africanist research of projecting characteristics of the ethnographic present into the remote past (Lane, 2005). 

The notion that "bow and arrow remains in widespread use in sub-Saharan Africa" is taken for granted and has not been afforded due specifics. It may well be the case in the more culturally-conservative hunter-gatherer holdouts, but such groups are by no means the extent or bulk of contemporary sub-Saharan demography. That aside, the lines worthy of a second look from the above passages, concern those detailing the reported contrasting trends between European MP specimens and those of the African MSA on one hand, and how prevailing prejudices in academia have only served to reinforce the respective perceptions formed around said specimens, on the other hand. The picture that emerges from the passages above suggest that the entries proposed for European MP are relatively more contentious than the African record, for reasons already stated.

To recap, Shea is saying that many European researchers (aka those primarily trained in or specialize in European prehistory) have had an ideological incentive for rejecting the potential for European MP projectile weaponry, driven by the urge to uphold "a longstanding tradition of viewing Neandertals' behavioral capacities as significantly inferior to those of recent Homo sapiens (Trinkaus and Shipman, 1993)," coupled with deficient prospects of projecting "patterned chronological and regional variation" of projectile weaponry of present day hunter-gatherer groups into European MP record [something that has been possible with prehistoric African specimens on the other hand]. Note however, that at the same time, Shea was not necessarily critical of the basic phenetic standpoints used to argue against European MP projectile technology.

It seems, to Shea, where the phenetic observations of European researchers fell short, is their capacity to differentiate prehistoric specimens with a high degree of resolution, which corresponds to the true state of functionality. As a result, there has been an inclination of many European researchers to inadvertently pool what amounts to "a few very large artifacts" with relatively smaller counterparts in a sample, thereby obscuring "the presence of a significant small point component". To put it in more blunt terms, a lot of strategies used in classifying stone tools do not apply enough determinants; to quote Shea, "the statistical characteristics of pointed artifacts from particular archaeological contexts may vary widely depending on the specific criteria used by different analysts to identify "points", and few typologies explicitly specify size thresholds for particular tool types." Consequently, strategies used to "systematize stone tool typology" have retained a "strong subjective component"!

Shea for his part, goes onto suggest that researchers should consider using "additional metric variables, such as mass, and symmetry in selecting samples for comparison and analysis," perhaps as a means to boost the discriminating capacity of their typological strategies. One concept, though, that appears to be a better discriminant in differentiating thrusting-spear points and projectile points, with respect to the most plausible function(s) of artifacts, is the estimation of what is known as "tip cross-sectional area" or TCSA.

The TCSA is said to be determined through the formula, (0.5 multiplied by "maximum width") multiplied by "thickness". It is reportedly effective in identifying "functionally-significant" variation among point-specimens, whether they be of known or unknown function; TCSA analysis has identified statistically significant differentiation between museum arrowheads (hafted ethnographic and recent archaeological arrowheads) and dart tip collections--comparative analysis of specimens examined in say, Thomas' (arrowheads and dart tips; 1978) and Shott's (dart tips; 1997) work, bear this out. Measuring "neck width" was useful in differentiating arrowheads from dart tips in Thomas' (1978) work, but Shea notes:

Unfortunately, few hypothetical MP and MSA stone projectile points feature such distinctive modifications for hafting.

Shea recalled a situation wherein his observations, that certain Levantine Levallois points from Kebara, Tabun, Qafzeh, Hayonim caves (all in Israel) and Tor Faraj rockshelter (Jordan) were possible spear points on the basis of wear patterns and their size, shape, and ecogeographically-patterned variation, drew some controversy, with other Levantine prehistorians, primarily ones trained in European prehistory, expressing "skepticism" towards the findings. According to Shea, the debate only lost some steam upon the discovery of a Levallois point embedded in the vertebra of an equid at Umm el Tlel (Syria)(Boëda, et al., 1999). He notes though, that this did not resolve the issue of whether said points were used as spears or projectiles.

Well, this presented a scenario wherein the estimation of the TCSA values of the points could have come in handy, to differentiate them into the most plausible functional roles. Perhaps the TCSA values of the said Levallois points would be able to place them into either thrusting spears, arrowheads or darts. The reliability or benefits of TCSA, are briefly summarized as follows:

TCSA effectively discriminates between hafted ethnographic and recent archaeological arrowheads and dart tips in museum collections. TCSA requires neither basal modification for hafting nor a complete tip on archaeological points being measured. It has the further advantage that the measurements needed to calculate TCSA are among those routinely recorded by Old World Paleolithic archaeologists in the course of their typological and technological analyses of Middle and Upper Paleolithic artifacts. Thus, it is possible to obtain large samples of point measurements whose statistical characteristics provide insights into the origins of projectile weaponry. - Shea

Indeed, doing just that (estimation of TCSA), the Keberan and Rosh Ein Mor points [with TCSA values under 100 mm square] respectively produced TCSA values that were not too far off the mean of the control dart tip sample, although these did not reach significance (i.e. statistical), while those from the Tor Faraj Level C site displayed significantly smaller TCSA values than the control dart tip sample. It should be pointed out that the control arrowhead sample produced a TCSA value that this fairly lower than that of the control dart tip. None of the test samples with TCSA values under 100 mm square produced TCSA values smaller than that of the control arrowhead sample. Shea admits that the choice of the 100 mm square value for control purposes is a subjective one, but qualifies its effectiveness with pointing out that it is "slightly higher than two standard deviations above the mean" TCSA score of the control dart tip sample.

These findings may indicate the availability of points in said Levantine samples, that were used specifically as projectile weaponry? Not so clear a picture, when other factors are taken into account! It has been determined, for instance, that this could very well be attributable to intense core reduction activity, particularly at the Tor Faraj Level C site, where most of the small Levantine Levallois points have been located. Refitting and technological analysis determined that the Tor Faraj  Level C bore the highest ratio of Levallois points to cores of all Levantine MP assemblages.

The European < 100 mm square Mousterian sample (from Payre) on the other hand, were determined to be larger than the control dart tip sample, although not statistically significant. Where does all this leave the < 100 mm square African samples? All the African specimens, except for the South African Klasies River Mouth MSA I-II points/triangular flakes and the coastal northern African Aterian tanged points, exhibited TCSA values significantly lower than the control dart tip sample. The Klasies River Mouth MSA I-II points/triangular flakes on the other hand, exhibited a significantly larger TCSA score than the dart tip sample, while the coastal northern African Aterian tanged points exhibited a score that is identical to that of the dart tip sample, but not statistically significant.

However, the Klasies River Mouth record also includes "backed pieces", which have been considered to be markers of projectile weaponry, according to Shea; the suggested possible applications are reportedly, either points, or, more likely, as barbs set into the sides of spears, darts, arrows, and other weapons (Deacon and Deacon, 1999). The various findings across the Klasies River Mouth collections may thus be reflective of the "long sequence of occupations", stretching back to 115 ky ago. Of the Klasies River Mouth "backed pieces", Shea says this:

Jebel Sahaba is a Later Paleolithic (c. 14 Ka) cemetery site from which numerous backed pieces were recovered in such close associations with human skeletons (in some cases embedded in them) that they are reasonably interpreted as projectile armatures (Wendorf, 1968). The backed pieces from MSA Howiesonspoort contexts at Klasies River Mouth are not appreciably thicker, on average, than various backed pieces from Jebel Sahaba. Thus, there is no reason to reject the hypothesis that at least some MSA backed pieces were projectile armatures. In addition, recent microwear analysis has also identified diagnostic traces of projectile impact on MSA backed pieces from Klasies River Mouth (Lombard, 2005c).

As for the coastal northern African Aterian tanged points, their TCSA score has attributed to a possible "systematic under-representation" of actual projectile elements in "older surface collections". It has therefore been suggested that additional studies of Aterian specimens from "controlled excavations" be undertaken to confirm the plausibility of this scenario.

To satisfy the curious mind, the African point collection of John Shea's study are said to "span the full length of the African continent" and "very nearly the full chronological range of the MSA", and hence representative of the African record. Brief mention of the Jebel Sahaba "back pieces" had taken place earlier, and tacit reference to that collection had occurred in passing in the following passage:

Stone points (retouched and unretouched triangular flakes as well as thinned bifaces) as well as backed pieces thin and narrow enough make them highly-effective projectile weapon armatures are broadly distributed among Southern and East African MSA assemblages. Such artifacts do not comprise a majority of any named artifact-type from any MSA site, but this is undoubtedly a reflection of the fact archaeological typologies for MSA stone tools do not take into account ballistically-significant size variation in making distinctions among named artifact types. The presence of such plausible projectile points in so many African MSA contexts suggests projectile weaponry may have been in use in Africa long before it appeared in Eurasia.

As far as harder data on the Jebel Sahaba collection goes, the author (John Shea) provides the reader with a "table 4", citing the mean values of the "maximum thickness" measurements, and featuring the various other collections from the Klasies River Mouth sites of South Africa. To sum it up:

Of all the Mid-Paleolithic or early projectiles examined by the authors...Only the African MSA data preserves evidence for stone tools whose ballistically significant metric (putting it into context, statistical significance here is reached at the level of p < .01) dimensions suggest design for use as projectile points.

A second argument supporting a possibly earlier antiquity for projectile technology in Africa involves the lithic “backed pieces” (aka “crescents” and “lunates”) found in some sub-Saharan MSA assemblages, most famously the Howiesonspoort variant of the South African MSA (Lombard, 2005b) (Figure 2). These backed pieces have long been thought to have been possible projectile armatures, either points, or, more likely, as barbs set into the sides of spears, darts, arrows, and other weapons (Deacon and Deacon, 1999).


Relevant visual aids (click on the images for hi res.):

Image captions: Image on the left - Figure 2. Backed pieces as projectile armatures: a & b. hypothetical mounting of baked pieces in wooden shafts, based on ethnographic examples, c. relationship between thickness of backed pieces and thickness of shaft, d & e. backed pieces from Klasies River Mouth Cave (South African) Howiesonspoort MSA, f & g. backed pieces from Late Paleolithic cemetery at Jebel Sahaba (Sudan). Image on the right - Figure 1. Examples of Middle Paleolithic and Middle Stone Age point-types discussed in this study: a. Triangular Flake (Klasies River Mouth Cave, South Africa), b. Still Bay point (Skildergat, South Africa), c. Bifacial point (Porc Epic Cave, Ethiopia), d. Unifacial point, (Porc Epic Cave, South Africa), e. Aterian Tanged point (Beni Abbas, Morocco), f. Levallois point (Qafzeh Cave, Israel), g. Levallois point (Kebara Cave, Israel), h. Levallois point (Houppeville, France), i. Mousterian point (Combe Grenal, France).

This wraps up the first segment of this discussion. The discussion is carried over to So What's the Deal with the Neanderthal, Their Demise? - II

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Neanderthal in the News:

Neanderthal Cloning Project


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