August 23, 2011
To be posted on

Paul Metlars
Department of Archaeology
Cambridge University
Cambridge CB2302

Dear Paul Metlars:
I enjoyed your article (Paul Metlars and Jennifer C. French Tenfold Population Increase in Western Europe at the Neandertal-to-Modern Human Transition SCIENCE vol. 333 no. 6042 July 29, 2011 page 623) giving evidence that there was an order of magnitude increase in the number of humans living in western Europe during the time that modern humans replaced Neanderthals.  (I use the old term if you will forgive me.  I tend to resist a change in word that is not justified by a new concept.  Any change that is just there to be modern I think of as an “anachronym.”) 

I had assumed that the moderns had a numerical superiority because of their more varied technology for getting food.  I enjoy the rare occasion when what seemed like common sense proves to be the truth.  Thank you for that.

You mention mating and alliance networks between groups of moderns as a potential advantage.  Yet modern humans seem to fall into two groups.  There is the vast global urban culture in which there is mating networking above and beyond the call of sanity.  The fertility in this massive majority of humanity is of course in decline.  There is a similar pattern among the Eskimo, among which anyone can marry anyone he or she meets.  But in those parts one really doesn’t meet many people.  The rest of the world, time proven cultures that have thrived modestly but stubbornly for untold eons, have very strict rules about kinship and marriage, which is to say they go together like a horse and carriage.  Everybody who has lasted very long has been marrying cousins.  Robin Fox is the authority on such matters.  His most recent book is The Tribal Imagination

So one wonders whether this kinship and mating system was part of the modern human success.  Lacking it, the Neanderthals would have been obliged to live in quite uncrowded fashion, like the Eskimo, with all the risks that entails when in competition with a denser population. 

You might well ask what possible advantage marrying cousins would have.  The significant one is that in the long run it lets you have babies.  There is a reference you might like to check out if you have any doubt.  It is a study done of kinship and fertility in Iceland. 

An Association Between Kinship And Fertility of Human Couples.  Agnar Helgason, Snaebjoern Palsson, Daniel F. Guobjartsson, Pordur Kristjansson and Karl Stefanson, SCIENCE vol 329 8 February 2008 page 813.

If you study the graphs you will realize that any randomly mating population greater than a certain size cannot make enough babies to replace itself.  And we now don’t. 

Let me know what you think.


M. Linton Herbert MD

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