Friday, November 21, 2008

Were Neanderthals stoned to death by modern humans?

 
Were Neanderthals stoned to death by modern humans? is the provocative title of a press release reported in New Scientist. The author of the study is interviewed,
Human aerial bombardments might have pushed Neanderthals to extinction, suggests new research. Changes in bone shape left by a life of overhand throwing hint that Stone Age humans regularly threw heavy objects, such as stones or spears, while Neanderthals did not.

"The anatomically modern humans would have this more effective and efficient form of hunting," says Jill Rhodes, a biological anthropologist at Bryn Mawr College in Pennsylvania, who led the new study. A warmer Europe would have opened up forests, enabling longer range hunting, she says.

Rhodes and a colleague studied changes to the arm bone that connects the shoulder to the elbow – the humerus – to determine when humans may have begun using projectile weapons.

"If we're trying to understand whether anatomically modern humans had projectiles, then why not read the signature that it can imprint in the skeleton," Rhodes says.
The paper by Jill Rhodes of the Department of Anthropology, Bryn Mawr College and Steven E. Churchill of the Department of Evolutionary Anthropology, Duke University appears in The Journal of Human Evolution under Article in Press.
Rhodesa, J.A. and Churchill, S.A. (2008) Throwing in the Middle and Upper Paleolithic: inferences from an analysis of humeral retroversion. [doi:10.1016/j.jhevol.2008.08.022M]
Here's the complete text of the conclusiosn from that paper.
Clinical evidence from professional and college-level throwing athletes reveal differences in the humeral retroversion angle both between athletes and comparative (non-throwing) samples and between the dominant (throwing) and non-dominant limbs in the athletes. Comparative analysis of humeral architecture, specifically the humeral retroversion angle, in Pleistocene fossil humans has the ability to contribute new insights into the origins of projectile weaponry by examining the individuals who would have wielded those weapons. While the data is equivocal (in part because of confounding variables that affect humeral retroversion and in part because of small fossil sample sizes), we can reach two conclusions. First, while Neandertals tend to have high amounts of humeral retroversion, the overall pattern between limbs and between sexes strongly suggests that it is not due to habitual throwing behavior. The humeral retroversion data is largely consistent with other lines of evidence pertaining to projectile weaponry; the preponderance of evidence, ranging from fossil spears and Mousterian lithics to the articular and diaphyseal morphology of upper limb bones, suggests that Neandertals did not habitually employ long-range projectile weapons ([Churchill et al., 1996], [Schmitt et al., 2003], [Shea, 2003a], Shea, 2006 J.J. Shea, The origins of lithic projectile point technology: evidence from Africa, the Levant, and Europe, J. Archaeol. Sci. 33 (2006), pp. 823–846. Article | PDF (774 K) | View Record in Scopus | Cited By in Scopus (15)[Shea, 2006] and [Churchill and Rhodes, in press]). It is worth noting that earlier hominins also lack humeral torsion, further demonstrating that the increased retroversion found in Neandertals is unlikely to be linked to throwing. Second, we cannot reject the suggestion of projectile weapon use in the European Upper Paleolithic. The patterns seen in bilateral asymmetry in humeral retroversion angle suggest a variable use of throwing in the middle Upper Paleolithic (and thus great inter-individual variation in asymmetry), perhaps related to regional differences in hunting practices or the importance of projectile-based hunting. The levels of asymmetry seen in late Upper Paleolithic males are consistent with the regular use of projectile technology by this time.
Is it just me, or does there seem to be a disconnect between what's in the paper and what's in the press release? Why would the author allow the press release to say something that cannot be found anywhere in the paper?


10 comments :

  1. I suppose the head line could have been:

    Bilateral asymmetry in humeral retroversion angle of Middle Upper Paleolithic Humans is evidence for throwing

    But come Larry use your loaf, the poor guy has got to earn a living and sell 'newspapers'! Only surprise is, he didn't somehow relate it to sex and religion

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  2. "Why would the author allow the press release to say something that cannot be found anywhere in the paper?"

    Do you think the author had any control over it? I've been misquoted in the media 2x - once I "cured" HIV (don't I wish; I actually showed a therapeutic had minor potential for some forms of HIV-assocaited infections), and I was once quoted as saying HepA was autoimmune (the seriously mis-read a 5-point long, point-form summary of our work).

    Probably the same thing happened here - reality was too boring, or the scinece not explained simply enough, so things got spiced up/reported wrong...

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  3. I would think that the burden of proof is on you to show that humans didn't throw spears at neanderthals, thus causing their extinction.

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  4. Headlines are to attract people's attention and incite them to by the paper/magazine. Graphic imagery is essential, truth is optional. Unfortunately most people take the headlines for truth and never bother to find out what the research actually says.

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  5. Unfortunatley papers on human evolution seem particularly prone to stupid press releases, to the point where you really should assume they aren't accurate.

    Besides--who wants to read all that boring anatomical terminology? :)

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  6. Bryan asks,

    Do you think the author had any control over it?

    Yes. This is a university press release. At the very least, the author should have demanded approval of the final version.

    Having failed to do that, the author should be requesting a retraction. Provided, of course, that the author really is appalled at the lack of accuracy in the press release.

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  7. Devin says,

    I would think that the burden of proof is on you to show that humans didn't throw spears at neanderthals, thus causing their extinction.

    Press Release, University of Toronto: Modern humans did not cause the extinction of Neanderthals by throwing spears at them.

    Consider it done.

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  8. This is not a university press release. It was a media interview in which the journalist disregarded the information imparted and spun the story in a more sensationalist fashion. The authors are appalled at the tabloid journalism practice employed at New Scientist and have protested the article.

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  9. anonymous says,

    This is not a university press release. It was a media interview in which the journalist disregarded the information imparted and spun the story in a more sensationalist fashion.

    That appears to be correct. I was wrong to assume that the story originated in a university press release.

    The authors are appalled at the tabloid journalism practice employed at New Scientist and have protested the article.

    Do you have a reference that I could quote? I'd love to publicize this.

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  10. If the authors had no control over it, then that right there is a problem. I think scientists need to ensure that their work is accurately relayed to the public. Often, the press releases make the results sound so comical or far-fetched, that it denigrates the value of science and confuses the public.

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