A Setback for Neandertal Smarts?

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A Setback for Neandertal Smarts?
by Michael Balter on 18 October 2010, 3:00 PM | Permanent Link | 0
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Neandertals are looking sharp these days. Many researchers now credit
our evolutionary cousins, once regarded as brutish and dumb, with
"modern behavior," such as making sophisticated tools and fashioning
jewelry, a sign of symbolic expression. But new radiocarbon dating at
a site in France could mar this flattering view. The study concludes
that the archaeological layers at the site are so mixed up that
ornaments and tools once attributed to Neandertals could actually be
the work of modern humans, who lived in the same cave at a later date.

One prominent researcher even argues that this celebrated site, the
Grotte du Renne (literally "reindeer cave") at Arcy-sur-Cure in
central France, should now be eliminated from scientific
consideration. "This key site should be disqualified from the debate
over [Neandertal] symbolism," says Randall White, an archaeologist at
New York University. But João Zilhão, an archaeologist at the
University of Bristol in the United Kingdom who has often tussled with
White and other researchers over the evidence from the Grotte du
Renne, says that the new study "prove[s] the exact opposite of what
[its] authors claim."

The Grotte du Renne was excavated between 1949 and 1963 by the late
French prehistorian André Leroi-Gourhan, who found 15 levels of
hominid occupation ranging from about 45,000 to 28,000 years ago. This
period includes the overlapping occupation of Europe by Neandertals,
who show up about 130,000 years ago and disappear no later than 30,000
years ago, and modern humans, who arrived in Europe between 45,000 and
40,000 years ago and stayed for good.

Leroi-Gourhan attributed the artifacts in the lowest levels to
Neandertals and artifacts from higher levels to modern humans, based
largely on the types of tools they made. But the middle layers at the
site included bone tools, ivory ornaments, and other sophisticated
artifacts that Leroi-Gourhan attributed to a culture called the
Châtelperronian. Although Châtelperronian artifacts closely resemble
those made by modern humans, many researchers have attributed them to
Neandertals because they have sometimes been found with Neandertal
fossils. Indeed, at the Grotte du Renne, Leroi-Gourhan found about 30
Neandertal teeth in the Châtelperronian levels, which can be
distinguished from modern human teeth based on the size and shape of
their cusps and other features.

Most debates about the Châtelperronian—which begins about 40,000 years
ago—have revolved around whether Neandertals invented it or simply
copied the behavior of incoming modern humans. But recently, some
researchers have begun questioning whether Neandertals made the
Châtelperronian at all.

In the new study, published online today in the Proceedings of the
National Academy of Sciences, a team led by dating expert Thomas
Higham of the University of Oxford in the United Kingdom reports 31
new radiocarbon dates from the Grotte du Renne, using new filtration
methods to purify radiocarbon samples and remove contamination by
modern carbon sources, which has long plagued dating accuracy. The
dates, obtained on materials such as bone tools and ornaments made of
animal teeth, painted a disturbing picture: Whereas upper layers
attributed to modern humans clocked in at no older than 35,000 years,
artifacts from the Châtelperronian levels ranged from 21,000 years
ago, when Neandertals were long extinct, to 49,000 years ago, before
the Châtelperronian actually began. Indeed, Higham and his colleagues
found that at least one-third of the Châtelperronian dates were
outside the known time period of this culture.

The team concludes that the archaeological levels must have become
mixed over thousands of years and that younger artifacts made by
modern humans may have moved down into levels long thought to be
associated with Neandertals. "The evidence from the Grotte du Renne
ought to be viewed with extreme caution," the authors write.

The authors do not speculate on whether the layers became mixed
through natural sedimentation processes or excavation errors that
caused some artifacts to be assigned to the wrong occupation levels.

White says that the results should not be surprising, because Leroi-
Gourhan's excavations took place "at a time when excavation techniques
in general were rudimentary." He adds that only one other
Châtelperronian site has produced personal ornaments, in much smaller
numbers, meaning that claims that Neandertals were capable of such
symbolic expression rests heavily on the evidence at the Grotte du
Renne. But Zilhão counters that two-thirds of the dates are consistent
with Neandertals having made the Châtelperronian. The other, outlying
dates could be the result of contamination rather than mixing of
artifacts among layers, he says.

Yet Higham, who has been redating nearly 20 other Neandertal and
modern human sites in Europe, says that the Grotte du Renne is unique
in producing such wildly varying dates. "I think this is telling us
something," Higham says. "This site has some problems."

http://news.sciencemag.org/sciencenow/2010/10/a-setback-for-neandertal-smarts.html

Paper abstract

Chronology of the Grotte du Renne (France) and implications for the
context of ornaments and human remains within the Châtelperronian

1. Thomas Highama,1,
2. Roger Jacobib,c,2,
3. Michèle Juliend,
4. Francine Davidd,
5. Laura Basella,
6. Rachel Wooda,
7. William Daviese, and
8. Christopher Bronk Ramseya

+ Author Affiliations

1.
aOxford Radiocarbon Accelerator Unit, Research Laboratory for
Archaeology and the History of Art, University of Oxford, Oxford OX1
3QY, United Kingdom;
2.
bBritish Museum, Franks House, London N1 5QJ, United Kingdom;
3.
cNatural History Museum, London SW7 5BD, United Kindom;
4.
dArchéologies et Sciences de L'Antiquité, Unité Mixte de
Recherche 7041, Centre National de la Recherche Scientifique, 92023
Nanterre, France; and
5.
eCentre for the Archaeology of Human Origins, Department of
Archaeology, University of Southampton, Southampton SO17 1BF, United
Kingdom

*

↵2Deceased December 9, 2009.

1.

Edited by Richard G. Klein, Stanford University, Stanford, CA,
and approved September 13, 2010 (received for review June 12, 2010)

Abstract

There is extensive debate concerning the cognitive and behavioral
adaptation of Neanderthals, especially in the period when the earliest
anatomically modern humans dispersed into Western Europe, around
35,000–40,000 B.P. The site of the Grotte du Renne (at Arcy-sur-Cure)
is of great importance because it provides the most persuasive
evidence for behavioral complexity among Neanderthals. A range of
ornaments and tools usually associated with modern human industries,
such as the Aurignacian, were excavated from three of the
Châtelperronian levels at the site, along with Neanderthal fossil
remains (mainly teeth). This extremely rare occurrence has been taken
to suggest that Neanderthals were the creators of these items. Whether
Neanderthals independently achieved this level of behavioral
complexity and whether this was culturally transmitted or mimicked via
incoming modern humans has been contentious. At the heart of this
discussion lies an assumption regarding the integrity of the excavated
remains. One means of testing this is by radiocarbon dating; however,
until recently, our ability to generate both accurate and precise
results for this period has been compromised. A series of 31
accelerator mass spectrometry ultrafiltered dates on bones, antlers,
artifacts, and teeth from six key archaeological levels shows an
unexpected degree of variation. This suggests that some mixing of
material may have occurred, which implies a more complex depositional
history at the site and makes it difficult to be confident about the
association of artifacts with human remains in the Châtelperronian
levels.

http://www.pnas.org/content/early/2010/10/13/1007963107

JTEM