[ExI] Recent human selection

hkhenson hkhenson at rogers.com
Thu Dec 20 17:51:42 UTC 2007

Being much influenced by the concepts of evolutionary psychology, I 
have tended to discount the idea of humans being much shaped by 
recent evolution.  Exceptions have been accumulating, the taming of 
wild foxes in as few as 8 generations, and the acquisition of genes 
(a number of them!) for adult lactose tolerance in peoples with a 
dairy culture.  Yes, you can get serious population average shifts if 
the selection pressure is high enough.

Now Dr. Gregory Clark, in one of those huge efforts that lead to 
breakthroughs, has produced a study that makes a strong case for 
recent  (last few hundred years) and massive changes in population 
average psychological traits.  It leaves in place that a huge part of 
our psychological traits did indeed come out of the stone age, but 
adds to that recent and very strong selection pressures on the 
population of settled agriculture societies in the "Malthusian trap."

I came a bit late to this party, Dr. Clark's book _A Farewell to 
Alms_ peaked at 17 on Amazon's sales months ago.  My copy has not 
come yet so I read this paper off his academic web site.


"Genetically Capitalist? The Malthusian Era, Institutions and the 
Formation of Modern Preferences."

There is lots of other material 
here:  http://www.econ.ucdavis.edu/faculty/gclark/research.html but 
this paper is just stunning because of how much light it shines on a 
long list of mysteries.  Such as: Why did the modern world grow out 
of a small part of Europe and why did it take so long?  Why are the 
Chinese doing so well compared to say Africa?

The upshot of his research was that in the Mathusian era in England 
people with the personality characteristics to become well off 
economically had at least twice as many surviving children as those 
in the lower economic classes--who were not replacing 
themselves.  This, of course, led to "downward social mobility," 
where the numerous sons and daughters of the rich tended to be less 
well off (on average) than their parents.  But over 20 generations 
(1200-1800) it did spread the genes for the personality 
characteristics for accumulating wealth through the entire population.

	"In the institutional and technological context of these societies,
a new set of human attributes mattered for the only currency
that mattered in the Malthusian era, which was reproductive
success. In this world literacy and numeracy, which were irrelevant
before, were both helpful for economic success in agrarian
pre-industrial economies. Thus since economic success was
linked to reproductive success, facility with numbers and wordswas
pulled along in its wake. Since patience and hard work found
a new reward in a society with large amounts of capital, patience
and hard work were also favored."

Fascinating work, memes that slot right in to the rest of my 
understanding of the world and the people in it.  I very strongly 
recommend reading this paper at least.

Keith Henson

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