Thomas Livingstone
The Neandertal Enigma: Solving the Mystery of Modern Human Origins.
By James Shreeve, Penguin Books, 1997,£8.99, ISBN 0140253335.
Target journal: New Scientist.
The great debate on human prehistory revolves around two conflicting theories of how modern humans evolved. Citing genetic evidence based on the rate of mutation of mitochondrial DNA , the fossil record and paleontological evidence, the "Single Origin model" suggests that modern humans arose recently (about 200,000 years ago) and in only one part of Africa. One of the implications of the theory is that Neandertals were an evolutionary dead end and not the ancestors of modern People. Alternatively, citing the paleontological and fossil records, the "Multiregional evolution model" suggests that modern humans arose more or less simultaneously throughout much of the world from populations of Homo erectus about 2 million years ago. The fossil record of Neandertals is explained as being on a point of an evolutionary continuum leading to modern humans. What exactly happened to the Neandertals is one of the biggest mysteries of prehistory and at this stage the available evidence is intriguing but by no means conclusive. The debate has inflamed the passions of protagonists from many disciplines, notably anthropology, genetics, geology, archaeology and fossil anatomy.
Having personally interviewed some 170 academics and experts in the field in his research James Shreeves has put together a fascinating account of the controversies surrounding the seemingly conflicting evidence from different fields. The main view points are put across in the context of discussions with many of the leading experts in the field, such as Milford Walpoff (leader of the Multiregional camp), Chris Stringer (Single Origin theory), Allan Wilson (genetecist) and John Shea (Archeaolgist and expert stone knapper). This makes interesting reading as we get some insight into the different personalities putting across their point of view and the way in which they have pieced together the evidence in their formulations of our early ancestors. The discussions along with the authors own reflections illustrate many possible scenarios and give rise to much thoughtful and sometimes insightful conjecture. At the same time the author does not ignore evidence that seems to dumbfound everyone such as the 80,000 year old beatifully engraved bone harpoons from Zaire. Found by Alison Brooks and John Yellen, nothing approaching their sophistication appears in the fossil record for another 50,000 years with the advent of Cro-Magnon man in Europe. This raises interesting questions, such as did this sort of artistry have to be reinvented several times before it really took off in human populations? The findings on Mount Carmel in Israel show modern and Neandertal type humans coexisting in very close proximity about 100,000 years ago. Add to this the fact that crucial access to the Chinese fossil record is severely restricted along with an explosion of archaeology in Australia and we have a debate that is very much alive and eagerly anticipating every scrap of new evidence.
One of the biggest problems in putting together anything like an accurate theory of modern human origins is the accurate dating of the evidence. The authors gives a clear exposition of all the main dating mechanisms upon which the various theories are contingent. The assumptions, limitations and problems associated with Radiocarbon dating, Radiopotassium dating, Mitochondrial DNA dating and Thermoluminesence dating are particularly pertinent to the debate as they lie at the core of the interpretation of the evidence. The problem is that fossils dated between 500,000 and 40,000 years ago cannot be dated accurately by either Radiocarbon or Radiopotassium dating. Unfortunately to get anywhere nearer resolving the question of what happened to the Neandertals means getting accurate dates precisely in this time frame. The newer techniques of Thermoluminesence and Mitchondrial DNA testing are still fraught with considerable difficulties and it is not clear how much we can rely on them. For example, the calculated rate of mutation of Mitochondrial DNA which is crucial to the notion of a genetic clock has been altered several times so far since the inception of the concept. This has led to a merry-go-round of cries of triumph and despair between Walpoff and Stringer which is well documented by the author and adds an element of human drama to the proceedings. The important point is that dating mechanisms, even if they are ``genetic", can often give rise to a great deal of misconstrued confusion. Nevertheless, the newer techniques are still becoming more and more refined and will ultimately prove to be of inestimatable value in clarifying the very complex fossil record.
What is good about this publication is the author's
even handed treatment of the different
protagonists and the abundance of interesting evidence presented. He has done his best to leave
no stone unturned and in doing so created a very readable and informative introduction to the
subject matter. Perhaps some of his conjectures about Neandertal consciousness are a little far
fetched, but they do serve to be thought provoking and worthwhile. His treatment of the
development of the debates in a historical-political context is good, but perhaps he is a little
sketchy in parts, for example the connection between the fake fossil of Piltdown man and the
contemporaniously fashionable philosophy of Social Darwinism is not discussed even though the
fossil was cited as evidence of European superiority at the time. For a good explanation of the
historical context behind the current debate see Chris Stringers "African Exodus: The Origins Of
Modern Humanity" (1996). Another minor problem with the book is the poverty of the
illustrations both in quality and number. More comparative
anatomies, maps and theoretical
timelines would definately enhance the wealth of information presented. Perhaps the most
enduring aspect of "The Neandertal Enigma" is that even after all the evidence and theories have
been presented we still do not
know what happened to the Neandertals. We are left with trying to
reconcile Walpoff's and Stringer's
passionate advocacy of their conflicting theories. On a light
note it is amusing that Shreeve's
observations that Walpoff is a "bear-like figure" and Stringer is
"lightly built" concur
entirely with their resspective theories. Walpoff is convinced that he is part
Neandertal and Stringer cannot see how he possibly could be.
Thomas Livingstone is studying in COGS at the University of Sussex
