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Friday,
June 3, 2005 It is column time and I am encumbered with much
writing.
Mail is piling up in a backlog and I will try to deal with a lot of it
this morning after my walk. There's a lot about the "true meaning" of Star
Wars Episodes I - III, which may read more into it than is there, but which
triggers interesting thoughts on Empire and Republic. I'll get that up.
There is also discussion on Global Warming with a NASA scientist. I had
hoped to have some analysis by people more familiar with the subject than
me, but it is unfair to keep this longer, so I will get that up shortly.
I have also delayed putting up Harry Erwin's Letter From England. I have
fixed that.
There is now a lot of mail up, some important, with many comments.
============
And all of you go read
http://www.economist.com/displaystory.cfm?story_id=4032638 by our friend
Greg Cochran. I expect much debate. This is one of the more important papers
to come out of being serious about applying the theory of evolution. (If you
cannot reach the web site, the article is appended below
until I find a proper link to it.)
The evolution of intelligence
Natural genius?
Jun 2nd 2005
From The Economist print edition
The high intelligence of Ashkenazi Jews may be a result of their persecuted
past
THE idea that some ethnic groups may, on average, be more intelligent than
others is one of those hypotheses that dare not speak its name. But Gregory
Cochran, a noted scientific iconoclast, is prepared to say it anyway. He is
that rare bird, a scientist who works independently of any institution. He
helped popularise the idea that some diseases not previously thought to have
a bacterial cause were actually infections, which ruffled many scientific
feathers when it was first suggested. And more controversially still, he has
suggested that homosexuality is caused by an infection.
Even he, however, might tremble at the thought of what he is about to do.
Together with Jason Hardy and Henry Harpending, of the University of Utah,
he is publishing, in a forthcoming edition of the Journal of Biosocial
Science, a paper which not only suggests that one group of humanity is more
intelligent than the others, but explains the process that has brought this
about. The group in question are Ashkenazi Jews. The process is natural
selection.
There are also comments:
http://www.nytimes.com/2005/06/03/science/03gene.html?
"It would be hard to overstate how
politically incorrect this paper is," said Steven Pinker, a
cognitive scientist at Harvard, noting that it argues for an
inherited difference in intelligence between groups. Still,
he said, "it's certainly a thorough and well-argued paper,
not one that can easily be dismissed outright."
Incidentally:
Hilarious meta confirmation. I don't know if it was
intentional... but note in the article who is quoted.
Jared Diamond, UCLA.
Stephen Pinker, MIT.
Paul Rose, Penn State.
David Goldstein, Duke.
Neil Risch, Stanford/UCSF.
Monty Slatkin, Berkeley.
What do all 6 of these people have in common? Hint: they are Ashkenazi Jews.
(The only possible non-Jew cited was Clark from Cornell).
Comments in Mail
=================
The high intelligence of Ashkenazi Jews may be a
result of their
persecuted past
THE idea that some ethnic groups may, on average, be more intelligent
than others is one of those hypotheses that dare not speak its name.
But Gregory Cochran, a noted scientific iconoclast, is prepared to
say it anyway. He is that rare bird, a scientist who works
independently of any institution. He helped popularise the idea that
some diseases not previously thought to have a bacterial cause were
actually infections, which ruffled many scientific feathers when it
was first suggested. And more controversially still, he has suggested
that homosexuality is caused by an infection.
Even he, however, might tremble at the thought of what he is about to
do. Together with Jason Hardy and Henry Harpending, of the University
of Utah, he is publishing, in a forthcoming edition of the Journal of
Biosocial Science, a paper which not only suggests that one group of
humanity is more intelligent than the others, but explains the
process that has brought this about. The group in question are
Ashkenazi Jews. The process is natural selection.
History before science
Ashkenazim generally do well in IQ tests, scoring 12-15 points above
the mean value of 100, and have contributed disproportionately to the
intellectual and cultural life of the West, as the careers of Freud,
Einstein and Mahler, pictured above, affirm. They also suffer more
often than most people from a number of nasty genetic diseases, such
as Tay-Sachs and breast cancer. These facts, however, have previously
been thought unrelated. The former has been put down to social
effects, such as a strong tradition of valuing education. The latter
was seen as a consequence of genetic isolation. Even now, Ashkenazim
tend to marry among themselves. In the past they did so almost
exclusively.
Dr Cochran, however, suspects that the intelligence and the diseases
are intimately linked. His argument is that the unusual history of
the Ashkenazim has subjected them to unique evolutionary pressures
that have resulted in this paradoxical state of affairs.
Ashkenazi history begins with the Jewish rebellion against Roman rule
in the first century AD. When this was crushed, Jewish refugees fled
in all directions. The descendants of those who fled to Europe became
known as Ashkenazim.
In the Middle Ages, European Jews were subjected to legal
discrimination, one effect of which was to drive them into
money-related professions such as banking and tax farming which were
often disdained by, or forbidden to, Christians. This, along with the
low level of intermarriage with their gentile neighbours (which
modern genetic analysis confirms was the case), is Dr Cochran's
starting point.
He argues that the professions occupied by European Jews were all
ones that put a premium on intelligence. Of course, it is hard to
prove that this intelligence premium existed in the Middle Ages, but
it is certainly true that it exists in the modern versions of those
occupations. Several studies have shown that intelligence, as
measured by IQ tests, is highly correlated with income in jobs such
as banking.
What can, however, be shown from the historical records is that
European Jews at the top of their professions in the Middle Ages
raised more children to adulthood than those at the bottom. Of
course, that was true of successful gentiles as well. But in the
Middle Ages, success in Christian society tended to be violently
aristocratic (warfare and land), rather than peacefully meritocratic
(banking and trade).
Put these two things together-a correlation of intelligence and
success, and a correlation of success and fecundity-and you have
circumstances that favour the spread of genes that enhance
intelligence. The questions are, do such genes exist, and what are
they if they do? Dr Cochran thinks they do exist, and that they are
exactly the genes that cause the inherited diseases which afflict
Ashkenazi society.
That small, reproductively isolated groups of people are susceptible
to genetic disease is well known. Constant mating with even distant
relatives reduces genetic diversity, and some disease genes will
thus, randomly, become more common. But the very randomness of this
process means there should be no discernible pattern about which
disease genes increase in frequency. In the case of Ashkenazim, Dr
Cochran argues, this is not the case. Most of the dozen or so disease
genes that are common in them belong to one of two types: they are
involved either in the storage in nerve cells of special fats called
sphingolipids, which form part of the insulating outer sheaths that
allow nerve cells to transmit electrical signals, or in DNA repair.
The former genes cause neurological diseases, such as Tay-Sachs,
Gaucher's and Niemann-Pick. The latter cause cancer.
That does not look random. And what is even less random is that in
several cases the genes for particular diseases come in different
varieties, each the result of an independent original mutation. This
really does suggest the mutated genes are being preserved by natural
selection. But it does not answer the question of how evolution can
favour genetic diseases. However, in certain circumstances, evolution
can.
West Africans, and people of West African descent, are susceptible to
a disease called sickle-cell anaemia that is virtually unknown
elsewhere. The anaemia develops in those whose red blood cells
contain a particular type of haemoglobin, the protein that carries
oxygen. But the disease occurs only in those who have two copies of
the gene for the disease-causing haemoglobin (one copy from each
parent). Those who have only one copy have no symptoms. They are,
however, protected against malaria, one of the biggest killers in
that part of the world. Thus, the theory goes, the pressure to keep
the sickle-cell gene in the population because of its
malaria-protective effects balances the pressure to drive it out
because of its anaemia-causing effects. It therefore persists without
becoming ubiquitous.
Dr Cochran argues that something similar happened to the Ashkenazim.
Genes that promote intelligence in an individual when present as a
single copy create disease when present as a double copy. His thesis
is not as strong as the sickle-cell/malaria theory, because he has
not proved that any of his disease genes do actually affect
intelligence. But the area of operation of some of them suggests that
they might.
The sphingolipid-storage diseases, Tay-Sachs, Gaucher's and
Niemann-Pick, all involve extra growth and branching of the
protuberances that connect nerve cells together. Too much of this (as
caused in those with double copies) is clearly pathological. But it
may be that those with single copies experience a more limited, but
still enhanced, protuberance growth. That would yield better linkage
between brain cells, and might thus lead to increased intelligence.
Indeed, in the case of Gaucher's disease, the only one of the three
in which people routinely live to adulthood, there is evidence that
those with full symptoms are more intelligent than the average. An
Israeli clinic devoted to treating people with Gaucher's has vastly
more engineers, scientists, accountants and lawyers on its books than
would be expected by chance.
Why a failure of the DNA-repair system should boost intelligence is
unclear-and is, perhaps, the weakest part of the thesis, although
evidence is emerging that one of the genes in question is involved in
regulating the early growth of the brain. But the thesis also has a
strong point: it makes a clear and testable prediction. This is that
people with a single copy of the gene for Tay-Sachs, or that for
Gaucher's, or that for Niemann-Pick should be more intelligent than
average. Dr Cochran and his colleagues predict they will be so by
about five IQ points. If that turns out to be the case, it will
strengthen the idea that, albeit unwillingly, Ashkenazi Jews have
been part of an accidental experiment in eugenics. It has brought
them some advantages. But, like the deliberate eugenics experiments
of the 20th century, it has also exacted a terrible price.
Comments in Mail .
See also this comment.
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