Friday, 13 September 2013

More Re: Karen Ruebens* and Neanderthal Lithic Cultural Traditions [?]—Part The First

Over the last two years I've barked at and bitten the referees and editors of most of the journals we depend on for new knowledge of us and our origins: Science, Nature, Quaternary Research (QR), QR InternationalQR ScienceJournal of Archaeological SciencePNAS, and the hapless PLOS ONE.

Moving right along . . .

The other day I promised more detail as to why I think Karen Ruebens's arguments in the Journal of Human Evolution (JHE) couldn't stand up to critical scrutiny. Today, I'm fulfilling that promise. This must be your lucky day!

Go here to access the paper.
I'm finding that I'm spending a lot of time on this critique. I suppose it's worthwhile to suggest a good reason as to why I should expect you or anyone else to follow me down this path. I think there's a really, really, important reason for both.

Karen Ruebens is claiming to have achieved what could not be achieved by others in the . . . oh . . . hundred-plus years that archaeologists have been seriously studying the Middle Palaeolithic (MP).

Think about it. It's akin to a fossil hunter revising the entire bipedal ape taxonomy and phylogeny. It's no small thing. And the media are already running with it, and in many languages.

It's for this reason it's imperative that we take a very close look at the premises, the evidence, and the arguments used in support of Ruebens s claims. If her claims becomes orthodoxy, those of us on this side of the palaeoanthropological fence will be rolling it uphill on an even steeper slope.

Get it?

Got it?


This paper deals with the "late" MP, about 115,000 ka to about 35,000 ka [i.e. Marine Isotope Stages (MIS) 5d–3, see below]. It was a time during which the Neanderthals had the run of Ice-Age Europe and western Asia—at the same time as the global climate was deteriorating. As you can see from the graphic below, the late MP started off at the height of the last interglacial. Initially the Neanderthals enjoyed a climate much like that of today. But, by the time Neanderthals disappeared from the fossil record, Earth's climate was on its way to being the coldest it had been for several hundred thousand years. The Last Glacial Maximum (LGM) occurred considerably later, and by that time our direct ancestors had been the sole inhabitant of Europe for some 20,000 years.

Marine Isotope Stages of the last 300,000 years. Dashed yellow line marks the division between warmer and colder global climate. Dashed grey lines delineate the late Middle Palaeolithic period discussed in the Reubens paper.
Actually, as I began reading this paper I had high hopes, because of what motivated the author: to unjumble the tangle of lithic technological terms and local and regional temporal and typological nomenclature used throughout Europe by palaeolithic archaeologists. Ruebens focusses on bifacially flaked stone artifacts from the last 20 kyr or so of the MP [from about 60 ka to about 40 ka], and a broad swath of Europe including France, England, the low countries, and Germany.

Data collection was aimed at acquiring observations on
1. artefact condition [oddly, not defined, nor does it form part of the presentation];
2. technology—raw material, blank, cortex, back, cross section, shaping and edge angles;
3. typology—both bifacial tool concept and bifacial tool type;
4. measurements and ratios. 
I put the terms concept and type in italics for a good reason: those words are a red flag to me. A concept can reside in the mind of the archaeologist; or, its use can bely the presumption or interpretation that a concept was formed in the head of, in this case, a Neanderthal rock knocker. As for the notion of a type, many of the 50 or so MP types defined by François Bordes are now seen as representing a stage in a time-transgressive sequence of flake removals that had no object other than to create and maintain a useful cutting edge. Many of Bordes's types were erected due to what's come to be known as the Finished Artifact Fallacy (FAF)—the idea that although we are able to group like with like, the group's constituents need not result from deliberate action. Harold Dibble's careful work on lithic reduction sequences gave us the best illustration of the FAF.
From Harold L. Dibble, "The Interpretation of Middle Paleolithic Scraper Morphology," American Antiquity 52:109-117, 1987.
The Ruebens paper's major claims are concisely laid out in the abstract, a snippet of which is reproduced below.
     Results indicate a high level of variation among individual bifacial tools and assemblages. Each bifacial tool concept is correlated with various methods of production, resulting in large degrees of morphological variation. Despite such variation, a distinct three-fold, macro-regional pattern was identified: the Mousterian of Acheulean Tradition (MTA) in the southwest dominated by handaxes, the Keilmessergruppen (KMG) in the northeast typified by backed and leaf-shaped bifacial tools, and, finally a new unit, the Mousterian with Bifacial Tools (MBT), geographically situated between these two major entities, and characterised by a wider variety of bifacial tools.
     Differing local conditions, such as raw material or function, are not sufficient to explain this observed macro-regional tripartite [word missing? division?]. Instead, the MTA and KMG can be viewed as two distinct cultural traditions, where the production of a specific bifacial tool concept was passed on over generations. Conversely, the MBT is interpreted as a border zone where highly mobile groups of Neanderthals from both the east (KMG) and west (MTA) interacted. [emphasis added]
This isn't the first time the author uses the term correlated, and while it's denotatively correct in this context, the reader's thoughts instantly presume that some robust statistical analyses will be presented. They never materialize. [Further down, these correlations will figure prominently.] Then the other shoe drops. We learn that the author has found evidence of cultural traditions in her research. I was on pins and needles to see the data! 

But, before getting into the gritty business of typologies, I want to pause and consider what the abstract tells us about the primary finding of Ruebens s work. I don't know about you, but after I read the abstract and consulted the map at left, my first impression was that what's identified as "a border zone," and a third "distinct cultural tradition"—the MBT—appears to be anything but. Seriously, the MBT is not a "border zone," even if it says so in the paper. The MBT spans the breadth of the MTA, yet it overlaps the KMG only for about half the length of the total overlap between the MTA and KMG. Moreover, this reader is wondering just how the author managed to distinguish between the two 'cultural traditions,' MTA and MBT, if the MBT is superposed. I say to author Ruebens: "Do tell!"

As I pored over the text and tables in this paper, it became clear to me that results are squarely based on the a priori presumption that the shiny biface thingies called different names in different places WERE, in fact, the result of concepts in the Neanderthal consciousness—she accepts, holus-bolus, the reality of the various artifact types. Having mentioned the FAF in her introduction, the author completely ignores it for the remainder of this paper. So, she addressed the 25 differently named biface types, lumped like with like, and arrived at five categories, or types, concepts, cultural traditions—you name it. 

Okay. Let's look at what the author distilled from the plethora of counter-productive local nomenclature and typologies. [Sorry to have to put up the entire table in what follows.]

Ruebens states that the five divisions are 
"defined by a diagnostic combination of technological and typological attributes, including the location and extent of the bifacial shaping and/or retouch, the number of cutting and backed edges, the cross section of the piece and its overall outline shape (Table 3). All five concepts can be viewed as rather distinct, with only few transitional forms being present in the archaeological record. Since each concept is based on least common denominators, morphological variation is present within each category, as expressed by differences in size and exact outline shape."
I know exactly what the term lowest common denominator means in arithmetic. However, I have no idea how I'm to understand its use in this context. I'm guessing it must be used figuratively. Unfortunately, it's never mentioned again. Table 3 follows. I had to put it sideways to make it legible. Sorry.
After having a look at Table 3, I think I might have a better understanding of what the author is trying to tell us when using the term correlation. I believe it's that her five concepts share many traits among them, but that each one has a unique 'signature.' Let's look closer at Table 3, although I have to say off the bat that it doesn't inspire confidence. 

Call me a pedant, if you want. But, I believe we can toss out the category "Location of shaping/retouch." Why? Because Ruebens has told us she's undertaking a study of bifaces! So, there's not much point in using ?bifaciality? as one of the diagnostic criteria. No. Wait! She's at least partly justified in using this parameter—one of the five type/concept/cultural traditions is bifacial  only some of the time. Hold the phone. What, fer gawd sakes, is a "partial biface?" A lump of rock is either a bifacially flaked something-or-other, or it's not! More reason to toss out the category.

You are the weakest link! Say goodbye to "Location of shaping/retouch."

I also think we can toss out the attribute of backedness? I mean, once you've recognized a feature of some artifacts, and called it backing, you shouldn't NEED any other criteria to distinguish backed things from things having no back. "Back" is an especially shaky criterion if three of the types may or may not be backed [which is what I take the term 'variable' to mean in this context]. Thus, this category is useful only useful, all of the time, to help distinguish hand axes from backed bifaces. What good is that?

Dave, what parting gifts do we have for "Back"?

Number of cutting edges seems another tosser. 'Cause, if backed bifaces and bifacial scrapers can have 1 or 2 cutting edges, and the other three can have only 2, then we're talking about seven types, not five. Fat lot of good that does! "Cutting edge" [which this research isn't, by the way] is only useful for distinguishing between the three that always have 2 cutting edges and the four other types that can't seem to make up their minds.

Gong! Get that talentless "Cutting edge" off the stage.

So, where does that leave us? Let's re-jig Table 3 using the criteria left once the unhelpful ones are tossed out.

Once the array is culled to this point, it's clear that "outline shape" is capable—all by itself—of uniquely identifying the five concepts that Reubens has proposed.

I guess it's all right if Ruebens wanted to go to so much trouble to substantiate the five concept type traditions. Problem is: to be usefully critical of this paper, this poor reader was compelled to go through the truly painful process that I've just dragged you through. Worse, others might be tempted to ask the question, "Where was the editor when this paper was undergoing review for its publishability? Where were the referees?" I'd never ask such questions. But others might.

So, you've just seen the author find a very strenuous way to replace good, old fashioned, typology.

It's time we saw some of those shiny bifacial thingies.

I extracted these images from each of the three figures in Ruebens's  paper, resized them to the same scale, and placed 'like with like.' Here's what I got. Look long and hard, but not too. Your head might explode.

As you can see, the objects in the left part of the frame are all termed hand axes. The others fall under what the author refers to as "backed and leaf-shaped bifacial tools," which comprise the other four concept/type/traditions. Can you see the same things I see? For example, how do you get a leaf shape out of any of those objects on the right? No plant that I know of has such asymmetrical leaves! And, frankly, the whole issue of the so-called backed artifacts gives me hives. I could easily see any of the 'backed' artifacts in this array arising from continued flake removals on a 'hand axe' such that it ceases to look like a hand axe. [Remember the Dibble diagram up top?]

Logically, the proximal—butt—end of the 'hand axe' that's been whittled down to something resembling the bottom four on the right. That butt would be identified as the backed portion, and the final flake removals on the opposite margin created one final cutting edge before it was dulled beyond usefulness and discarded.

Tell me I'm wrong. Isn't that what the FAF is all about? Regardless of your position on hand axes, it's straightforward: if the FAF is in play with hand axes, logically we should be able to see the results of gradual further reduction along the lines that we saw in Dibble's work with MP scrapers.

Fellow FAFsters, start your engines!

[By the way, no doubt because I'm Anglophone and geographically deprived, I'd never heard of either the Keilmesser or the Faustkeilblatt before today. Live and learn.]

Table 3 isn't all that this paper is about. If it were, I'd be breathing easier. Instead, Ruebens goes on to consider other parameters of European MP bifaces in an effort, one imagines, to bolster her identification of the five concept/type/traditions and to set the stage for the new map of MP Europe. I'm keeping an open mind. [As if.]

So, we've come to the point where I sum up this installment of my remarks on the Ruebens paper.

Here it comes. The summary.

I hope that the referees and editors are squirming by now. This story doesn't have a happy ending for the JHE crew, and it's not the fault of the author.

Next time I'm gonna get into the metrics of this revision of the MP of Europe. Hold on to your hat!

* I apologize for spelling the author's name incorrectly throughout the earlier version of this piece.


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