Friday 21 September 2012

Finlayson et al. on Corvids and Raptors and Neanderthal Use of Birds

I'm left stunned by Finlayson et al.'s article in the ever-preposterous PlosOne. I'm stunned for several reasons, and I think that I shall forego a fine-toothed critical approach in favour of a few well-chosen questions of the team that published this terrible piece of scholarship [and I'm being charitable here, in case you weren't aware].
     The article, if you haven't seen it, is a wonderful example of what [I think] Clyde Kluckhohn termed 'wallowing in minutiae.' The authors say that they're investigating 'the existence of universal patterns of early use of feathers for ornamental and symbolic purposes' among the Neanderthals.' They claim to have found that 'the relationship involves active processing of raptors and corvids by Neanderthals for the purpose of wing feather removal. 'Splain somthin' to me, Lucy:

Question One: Why would a burly Neanderthal need a stone tool to extricate feathers from [even a largish] bird? For those of you who haven't been brought up in the time of the rural to urban population transformation in North America, I'll inform you that modern human females of all ages and physical characteristics have been, historically, and still are, theoretically, capable of PLUCKING a gawd-dammed bird without the need for a GD knife--stone or otherwise. But we're supposed to accept that the Gibraltarian Neanderthals left seriously minute scratches on tiny bird bones because they were removing the feathers for use as ornaments and fashion accessories.
Excuse the upper case: HOW LAME CAN YOU BE? Finlayson et al. are clearly so infatuated with the idea of symbolic behaviour among their beloved Neanderthals that they've lost all touch with reality! If you don't believe me, assemble for me a small bibliography on archaeological bird butchery. I double-dog dare ya.

Question Two: Where do the authors get the idea that you need to butcher a bird? I have to think it's by analogy to making an elephant carcass useful! But, if you've ever spent more than a little time in the kitchen, you'll know that raw bird meat is relatively easy to remove from the bone with just your bare hands. Imagining that a Neanderthal needed to dismember a bird carcass in order to eat it is LUDICROUS! Raw or cooked, they're small enough to carry around without the need to butcher them to make individual packages that are easy for one person to carry! Furthermore, cooked bird meat is DEAD EASY to remove from the carcass with your bare teeth! Where do these ideas come from?????

Question Three: Who said that a 50-micron-wide linear scratch on a piece of bird bone is unequivocally evidence of butchery?? The authors looked at the corvids and raptors from the Gibraltar sites and found vanishingly few with such marks on them. What, one wonders, would they have found if they'd examined the skeletal remains of the non-corvid, non-raptor bones in the same sites. Doh!

As I said above. I decline to look further into the data and the data manipulations that Finlayson et al. present in this paper. Without even breaking a sweat I can see that their presence/absence data from 1699 palaearctic palaeontological and archaeological sites is statistically incapable of yielding useful results, especially since they ignore the presence of other kinds of birds at all the sites they employ.

Their premises are preposterous, and so are their results. Someone, please, prove me wrong, and I promise I'll stop slagging PlosOne.

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5 comments:

  1. These are not regular feathers but flight feathers, which are attached directly to the "arm" of the bird: the ulna (a bone of the forearm) and the manus (the equivalent of our hands). That explains why cuts were necessary to properly extract the feathers, which are strongly attached as they are fundamental for the survival of flying birds and must be individually rotated.

    Sorry but in this case you seem the one to be wrong.

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  2. Hi Rob,
    I just recently became aquainted with your blog and am currently reading my way backward (appropriate for the subject, no?). I will probably wait till after I finish the list before I start commenting on the rest, but on this subject I can no longer control myself.
    [Please note that I'm not an archeologist, I'm not even a student- in fact I can't even claim to have taken a class way back when. I'm just someone who has followed this subject for the last 40 years or so. So please don't bust my balls if I'm more ignorant than you. But I'm dismayed at what looks to me like the acceptance of an assumption by everyone- including yourself- regarding Neandertals and their status as a separate species.
    You call yourself the "The Subversive Archeologist", but Rob, where is your proof that Neandertals aren't the same species as sapiens? I admire what you're doing here, but this underlying assumption, that: {a hominin that looks and acts differently from us cannot be the same as us} would seem to this observer to be as flawed and archaic as any of the rediculous papers being written which you skewer regularly on these pages. If there is proof of this, what is that proof? Thank you for your time, Jim Gamble

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  3. Hi, Jim
    I'm gratified whenever someone is daft enough to admit to reading my stuff. So, thanks for taking the time. And thanks for your comment.
    Yours is the ultimate question.
    One of the best accepted characterizations of a species relies on the concept of reproductive isolation. Boiled down it means that if you and I don't see each other as potential mates, in all likelihood we won't be producing any offspring. Reproductive isolation is a difficult thing to demonstrate if all you're dealing with is the archaeological and palaeontological record. And I'd be much happier if it were possible to ask a Neanderthal that question. And therein lies the crux of the issue, as far as I'm concerned.
    We modern humans are capable of doing what you and I are doing at this moment, communicating using conventionalized, arbitrary symbols---infinitely expressive systems of sounds, gestures, nods, winks, pixels, alphabets, and so on. Whether or not the Neanderthals resemble us skeletally, to be the same species as us it's crucial whether or not they were similarly equipped, cognitively, to think, act, and communicate in the same way as we do.
    Since we can't talk to a Neanderthal, we must rely on the archaeological traces of their behaviour, and on sound inference-making, to arrive at an understanding of their cognitive abilities.
    And that's where I come in. The work that I "skewer" is fundamentally aimed at arguing for modern-human-like cognitive abilities in the Neanderthals. And as you're realizing, there are many, many studies that are fundamentally flawed. To my mind these flawed studies call into question the notion that Ns were enough like us to have been viewed as likely mates.
    I hope this answers your question. Thanks for coming along on this odyssey! Rob

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  4. In fairness to Jim, I think you did not quite answer his question. How do we know that neandertals were different species?
    One answer would be that we now know quite a lot about the genetics of Neandertals. Not as much as we think, but enough, within the statistical parameters of such things to know that neandertals and people had a common ancestor in the order of 300 thousand years ago. We do not, of course, know much about the rate at which new species become separate, but there is pretty good evidence that there was substantially no interaction in Europe or anywhere else for at least 200 thousand of those years.
    But Jim's point is well made that the "species" names invented by physical anthropologists do not prove that separate species existed, just that it is convenient to talk about patterning in the variation in the fossil bones as if it was the result of speciation.
    In this context, much has been made of the fact that many modern people share 4% of their genes with neandertals, but my attitude to that is, why so little. I think I have expressed that wrongly, since we share 98% with chimpanzees, but the point is that attitudes to species closeness are determined very much by our intuitive expectations rather than by any hard and fast scientific rules.
    Iain

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  5. @Jim,

    Between us, I think that Iain and I have answered your question. However, I think that the water may still be a little muddy. I hope the following helps.

    As Iain points out, there are many statistically significant morphological differences between Ns and Us. Ns lie outside the range of modern human skeletal variability. But morphology alone cannot [realistically] supply us with an unequivocal species distinction. That's because, as I said in my earlier response, we have no way of knowing whether or not we were reproductively isolated from the Ns. The recent comparisons between the N genome and those of [some] present-day humans contain nothing that could settle the issue of reproductive isolation. The only unequivocal result of such comparisons is that our two genomes contain identical stretches of DNA that testify to our shared ancestry.

    I'd consider it extraordinary if the geneticists hadn't found a significant overlap. After all, as Iain remarked, the Ns and we split from the lineage to which we both belonged at least 300,000 years ago. It was always intuitively obvious that members of genus Homo would share more DNA between them than we do with chimps because chimps and the Homininae have been following separate evolutionary paths for anywhere from about 3 to about 7 million years. We share 98% of our genome with chimpanzees---we should share considerably more with our nearest hominid neighbors.

    In short, geneticists can only make parsimonious inferences based on the evidence they possess. Yet, without the genome of the common ancestor it's still an empirical question whether or not stretches of N and our DNA are shared because we interbred or simply because our common ancestor possessed those same stretches and passed them on to the two novel lineages, Homo sapiens and . In that respect, the jury's still out where genes are concerned.

    So, back to the question of species within the genus Homo. Where the earliest Homininae are concerned, morphology is about the only way to make species distinctions. That's fine for the early genera---i.e. Australopithecus, Paranthropus, etc. However, within the genus Homo, morphological species are at best a starting point. That's because members of genus Homo are associated with flaked stone---variously called 'stone tools,' 'lithic technology,' or 'stone artifacts,' 'cultural complex,' and so on. I'd hasten to add that making the decision to call these products of behaviour by titles such as those just named entails implicit inferences regarding those creatures' cognitive abilities. And so, with respect to the time of the earliest stone artifacts the arguments become based less on morphology---e.g. cranial capacity, dentition, limb lengths and so on---and more on behaviour.

    [Aside: Notice that I just used the term 'stone artifacts.' It's important that we all employ a common terminology when discussing such matters. But, using identical terms for the same observations can only be useful if both users agree on what the implications of any given term. I use 'stone artifacts' without implying anything about cognitive ability, whereas another archaeologist might believe that such behaviors necessarily indicate higher-order cognition than that possessed by the non-human great apes.]

    Significant morphological differences exist in genus Homo. However, such distinctions are only provisional. We can't say for certain that we'd've considered any of our fossil relations to have been suitable mates. To answer that riddle, we must rely entirely on archaeological interpretations.

    And that, for me, is where the rubber hits the road. My efforts have always been aimed at sorting out robust inferences from those that are, at best, equivocal, given the archaeological observations used to support them.

    Thanks again for your question.

    Best wishes, Rob.

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