From the article
"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."


This should be easy enough to check out, I guess you just have to test whether heterozygotic carriers of Tay-Sachs disease on average score higher on IQ tests than non carriers. This part of the theory appears a bit whacky to me.

The general idea that Ashkenazi IQ rose through harsher evolutionary pressures placed on the Jewish people appears plausible. Especially since gentiles seemingly hardly had a chance at social mobility in the feudal system, so the smartest didn't rise and have larger offsprings, while Jews mostly were no serfs but merchants in the towns with larger social discrepancies, depending among other things on your abilities.

Congrats to Greg on finally getting it published, and getting mentioned in The Economist!

You could make me even happier. Guess how?

"This part of the theory appears a bit whacky to me."

Why?

congrats on the face time.

Perhaps it it will be useful, perhaps not.

All my profs in anthropology parrot the "cultural construct" party line. I switched from cultural to physical anth in part from stumbling across "Overclocking" on JEP's web page. (I don't even remember what I was searching for.) Inherited genetic qualities aren't even mentioned in college, except when villifying "racist ideologues." Eugenics is nearly synonymous with Nazism. Imagine if the Pentagon abolished staff command because the Germans invented it and you've got a pretty good similie for the current state of the social sciences. (Yes I know the Nazis copied their eugenics laws from America's 1922 laws.) I may have to spend more time defending my term papers than my classmates combined, but I can do so. (I enjoy doing so.) Damn straight publication is useful.

I just emailed the article to a Jewish friend of mine. He mentioned that most Jews aren't carriers for either disease so wondered how meaningful the research into the correlation was going to be.

I don't think that mutations causing disease in homozygotes are the whole story, but they make up thee part of the story that has been extensively studied.

If you look at gene freqeucnies of things that look like IQ boosters, the fraction of carriers among the Ashkenazi is higher than you might think: non-classic congenital adrenal hyperplasia (CAH) is said to have a gene frequency of about 20%. Add it in with the sphingolipid and DNA-repair mutations and we're talking a big fraction.

He mentioned that most Jews aren't carriers for either disease so wondered how meaningful the research into the correlation was going to be

well, a lot are. at least from my personal acquaintances (tay sachs carriers, etc.)...but then again, all my jewish acquaintances are probably in the right half of the jewish bell curve...hm....

I finally checked one of those small mysteries that I had never looked into. Nothing to to do with genes, but for anyone who is curious and doesn't already know.

Ashkenazi
[Medieval Hebrew 'aknzî, from 'aknaz, Germany, adoption of Hebrew 'aknaz, name of one of Noah's grandsons and of a neighboring people, perhaps alteration of earlier *'akûz, Scythians; akin to Akkadian aguzai, ikuzai, from Old Persian Saka-, Ska-.]

Nazi
[German, short for Nationalsozialistische deutsche Arbeiter-Partei, National Socialist German Workers' Party.]

i dont get the connection to CAH that Dr Cochran mentioned earlier

Mild or non-classical congenital adrenal hyperplasia due to a "defect" in steroid 21 hydroxylase causes an IQ boost in carriers and those affected.

It is not a serious condition: that is why defect is in quotes above. It does seem to have consequences for female personality: careerist tomboys essentially.

Henry

There are lots of studies that indicate that carriers for CAH, and people with mild cases (not salt-wasting) are smarter than average: smarter than their sibs. I think we found five or six.

MDs will routinely tell parents that CAH kids tend to be smarter, just as neurologists tell people with torsion dystonia that 'it makes you smart'.

But that's all stuff man was not meant to know.

Like I said long time before, persecution promote intelligence. The best selective pressure for human evolution is not other animal or nature any more. Actually human themself are true competitive and selective pressure. Any country or region went through long history of brutal ethnic cleansing would produce such seletive evolution pressure. European countries had hardly any peace over last two thousand years.

Today, Chinese themself are competing themself aggressively. In book China Inc. low price and razor thin profit margin in China are result of Chinese competing against among themself. Some time Chinese treat foreigners better than their fellow Chinese the same way human some time treat other animal better than their fellow human. It is because others are not considered competitors.

With today's discrimination toward black Americans, the selective pressure for them is higher than white people if you look at rate of survival or mortality rate. Thousands years later, black people might surpass white people in IQ if selective pressure continue higher for blacks. White nationalist are the people who will keep such pressure low for white people by helping low end of white trash. In the long run, Nazi ideology will turn master race into stupid race.

persecution promote intelligence.

read page 3 of the paper.

Persecution didn't make Gypsies extremely smart.

"Today, Chinese themself are competing themself aggressively."

Has anybody else here read "The Singapore Story" by former Singaporean prime minister Lee Kuan Yew? Makes for some really interesting reading, the book can be bought at amazon.com.

Among many other things he writes about some village in China where a lot of really smart people in Singapore supposedly came from. In this village there was a tradition over many generations that the richest peasants had lots of wives, while the poorest peasants could not find any women to marry and were genetically "neutered" as he calls it, so people supposedly became smarter than in other parts of China, where this was less common.

Lee also writes that in his opinion catholicism worked dysgenically, since the smartest men tended to become priests and live celibately.

"Persecution didn't make Gypsies extremely smart."


Maybe in their line of trade it made them into good hucksters ;)

most of the singapore chinese have their origin amongst the various fujian coastal clans (know from their mercentile spirit and hyper-patrilineal system of descent) or are hakka.

also

1) the higher ranks of the catholic clerisy was often selected on nepotistic elite connections

2) even acknowledging that only the 11th century reforms really enforced clerical celibacy, the common practice of such men siring bastards (like erasmus) was another talking point of lutherans. also, i would not be surprised if priests cuckolded many of their "charges."

Look at the little graphic in the NYTimes article. Slightly garbled, but not bad. There are actually a few genetic diseases among the Ashkenazi that are probably _not_ the product of selection for IQ, rather for disease resistance - but you see them in other populations: CF, connexin-26 deafness, and familial Mediterranean fever. Four if you count alpha-thalassemia, but it doesn't make many people sick.

"Persecution didn't make Gypsies extremely smart." Gypsies aren't attempting to compete by integrating into a capitalist economy. "g" seems to correlate not with economic success, but with western capitalist economic success, which is so much more sucessful than any competing system (assuming you have a large enough smart fraction in your populace; sub-Saharan Africa can't get it going. Success in s-S African economic terms might be correlated with naturally produced testosterone, so General Butt Naked takes over a huge hunk of Nigeria. Hat tip to Steve.) Western capitalistic economics beats all other systems, to the point where we forget that there are other ways of doing things (based on the talents of those who did them) because they can't compete. They can't even stay in the race long enough to get noticed. (The USSR was a western capitalist economy, they just substituted market forces with political wishful thinking and got what was coming to them.)

Success in s-S African economic terms might be correlated with naturally produced testosterone, so General Butt Naked takes over a huge hunk of Nigeria

you need to define "success." remember that

1) lebanese and asians west and east africa are more economically successful than indigenes.

2) but their birthrate is probably lower. don't know about their testosterone, but they aren't known for being hyper-aggressive.

3) so are they "successful"...at least economically in terms of production.

4) in any case, saying this "The USSR was a western capitalist economy" suggests to me you ought to define what you mean by "western capitalist economy," because by any definition i work with, a robust tradition of private property that is contractually enforced is necessary for a WCE and i don't know if czarist and communist russia had that on any large scale, and i am not sure that modern day russia really does. see the russian moment in world history (i don't know of the slavophiles or westernizers are right about russian culture, but the fact that the former are often thought of as "traditionalists," albeit myth-makers, should point us to the substrate we are working with....).

Let me add my congratulations gcochran. What I noticed about the articles discussing your paper was their overall positive tone. That is no small victory. Initially I thought that the New York Times might have had their readers' interests in mind, but then remember reading other things by the same author, and realized that he is the guy who writes on race-based medicine etc., and is much more likely to understand the science than care about being pc. So, so far so good.

My apologies, I carried an argument (and a definition) over from another discussion. When I read your blog I understand that "success" more often than not means "genetic reproduction." I used the word here in the sloppy sense of "just winning the game." (eg David Geffen; billionaire, ceo, lack of offspring not considered.)

Indigenous s-S Africans had an economy capable of building Great Zimbabwe. They didn't have a large enough percentage of their population capable of performing the logistic tasks of supporting a larger population on their land base and would have been overrun by Europeans if it weren't for malaria and other tropical diseases. "Winning the game" in current indigenous s-S African economic terms requires not starving and not being chopped up by someone with a machete. This isn't sufficient for winning but seems to be pretty damn important.

4)The USSR had a hierarchical society and the upper class of it had mansions, limosines and servants. They may have *said* there was no private ownership of property, but if you were of the proletariat and needed to be rushed to a hospital and Andropov would be in the Lubyanka bordello for the next few hours what are your chances of using his Zil? The "to each according to his need" half of the equation wasn't pursued with quite the relentless intensity as the "from each according to his ability." Marx's remedies were insane, but he did have some insightful analysis and he was fascinated by capitalism. The USSR had the problem of having to feed a hell of a lot of people (or not feeding them, but selectively) and that required logistics. OJ Simpson doesn't have a penny to his name, if he did he'd have to pay it to the families of Nicole Brown Simpson and Ron Goldman. He lives the lifestyle of a millionaire, but he can legally state that he's a pauper because his assets are hidden from the courts. The USSR used a western capitalist economic model but changed a bunch of terminology because they weren't going to admit that they were a group of criminals who stole the possessions of the previous aristocracy and assumed their position. They removed market forces from the equation (or so they thought) but they also slavishly aped the west, feigning economic growth with their investments in heavy industry following WWII.

I concede your point, I'm using terms in a confusing manner. Rather than using commonly understood economic terms I'm lumping groups together based on what their g says they're capable of producing. Bureaucratic states (and boy does the USSR qualify for that status) seem to maximize the economic potential of their smart fraction.

Gypsy tradition, as different from Jewish one, actively discourages learning as time- and life- wasting activity. One of their saying is "Even a gadjo (White) doctor is powerless against death, so why bother?"


The only manifestation of IQ approved might be "cheating of gadjo". Anyway that's the only type of applied intelligence praised in the recently published book of Gypsy fairy-tales.

Hardly a way to prosperity.

There are lots of other populations which share the Ashkenazi historical profile, e.g. Parsis, Marwaris, African Lebanese and Asians - is there similar data for them?

Now, with the ubiquity of assortative mating, could the same factors currently be at work in the general population?

Koa: I am an Ashkenazi Jew, and I can assure you that this line of inquiry makes most of us distinctly uncomfortable (including me).

Do Ashkenazis have larger brain volumes relative to others?

I also think that selection works on culture much faster than on genes (assuming the "alleles" are present), and this is a big part of the story of Ashkenazi success.

anyone else note that 6 of the seven individuals quoted in the article were of jewish ancestry? Pinker, Rose, Diamond, Slatkin, Risch, and Goldstein.

that's interesting on three levels.

1) it is a meta confirmation in miniature of the "ashkenazis are high IQ" theory

2) it indicates that ashkenazi jews are being called in to decide whether a hypothesis about their community is true or not

3) they are not labeled as ashkenazi jews explicitly in the article


Points 2 & 3 would be very different if this was an article on, say, black IQ. Then black views on IQ testing would be quoted as being *black views*, such that the reader could take whatever ethnic grains of salt he wanted -- just as Murray's view on IQ is considered a *white view* and taken with an ethnic grain of salt by people on the left.

David B,
Just so I understand, are you uncomfortable with the natural history of Ashkenazi intelligence being studied? Mind you, if you are commenting on Koa's piece about the last four letters, I agree with you. There is no synergy.

Pericles

David, I had read that many Ashkenazi are uncomfortable with this kind of thing for obvious reasons. http://www.ishipress.com/ashkenaz.htm
Many, however seem not to be. Since I can only claim 1/4 Ashkenazi, I am not sure what the Ashkenazi in me feels about it. My guess is the Sephardic in me doesn't care. The remaining half is likely an interested observer, although genetically different from the above observer (who makes valid points). ;-)

"Koa: I am an Ashkenazi Jew, and I can assure you that this line of inquiry makes most of us distinctly uncomfortable (including me)."

Interesting. I have a Jewish friend who feels the same way. My guess is that there is a subconscious fear among Jews that if word gets out there will be pogroms based on resentment. Perfectly understandable at least intellectually though not necessarily at a gut level to me. I read somewhere that a high majority of Japanese think the Protocols of Elders of Zion is not a forgery but *admire* the Jews because of it. But the western gentile response to high Jewish achievement has at times been radically different.

For the record, I am not David Boxenhorn!

I think the Cochran et al theory is very ingenious and worthwhile, not least because it is open to empirical testing of brain physiology, etc.

That being said, I would be sceptical about the idea that selection for high IQ has led to genetic diseases. The average IQ of Ashkanazi Jews is about the same as the professional (gentile) middle classes, who are a similarly selected group, and also largely endogamous (though less so than AJs). Are the same (or similar) genetic diseases also found among high IQ gentiles? If not, why not?

"In the long run, Nazi ideology will turn master race into stupid race."

I think that happened in South America somewhere. Some kind of inbred German commune. I wonder about Israel too - does it have a dysgenic effect on the Jews? In the sense that it is a safe (ish) home for the Jews. There might be selection for aggressiveness in Israel (esp. with the arduous compulsory National Army Service - those Israeli women are tough), but I'm not sure about intelligence. The national IQ of Israel is in the 90s as far as I can remember.

professional (gentile) middle classes, who are a similarly selected group, and also largely endogamous

Not necessarily. In Czechia, formerly under Austrian/German rule, a substantial part of middle class arose in 19th and the first half of the 20th century from the villager strata. Many became teachers (the shortest, therefore most affordable education option). In the extended families, occupations were found on the scale from small farmer to university prof. Additional "fresh blood" from working class came under the Communist rule, when the studium became even more affordable.

Speaking of endogamy - university educated young men here tended to marry not their female colleagues, but often one education degree down. Such spouses weren't actively pursuing a career and therefore were able to unite their less demanding job with homemaking (double income was and is a necessity in Czechia)

I read somewhere that a high majority of Japanese think the Protocols of Elders of Zion is not a forgery but *admire* the Jews because of it. But the western gentile response to high Jewish achievement has at times been radically different.


No. It's much more complex than that. That admiration is tinged with racial fears too, even in Japan. I should note that the Japanese perspective isn't at all atypical for anti-Semitism. Many Nazis viewed Jews in the same way - as the cleverest race next to Germans, and therefore their most dangerous and inherent competitor for world domination. Remember Mathir Muhammed, saying that Jews control the world through their invisible coup on the American government, and that the Islamic people should follow their example? That was "admiration" too, but it was scarcely different than the German perspective and Kevin Macdonald.

Question:

Am I misunderstanding the theory or does

Using Genetic Tests, Ashkenazi Jews Vanquish a Disease


Also mean:

"Using Genetic Tests, Ashkenazi Jews Vanquish their intelligence"?

Am I misunderstanding the theory

There is no reason to think that all genes selected for, or even most of them, have deleterious side effects.

Jason,

I don't see how artificially selecting - via genetic testing - against homozygous gene expression of deleterious diseases, decreases the positive selection for heterozygous gene expression naturally?!

In Israel, every pregnant woman is screened for a host of genetic diseases as part of her routine blood test. If she tests positive for something, the father is tested.

My wife didn't test positive for anything (and she's very smart!) and I've never heard of anyone else testing positive either. True, it's not something that people would talk about, but if it were common I would have heard about it from someone we're close to.

"With today's discrimination toward "...White nationalist are the people who will keep such pressure low for white people by helping low end of white trash. In the long run, Nazi ideology will turn master race into stupid race." We have a saying here, "you can't make a silk purse out a sow's ear" -- no matter how much pressure you put on it.
AG, where do you live? And are you in a time warp? Here in America, even the most "oppressed" are resource-guzzling SUV drivers with their rights protected in courts of law, as they are in all official democracies. Perhaps for the first time in recorded history, one race has actually legislated to prevent its own kind from getting certain social amenities so that a formerly oppressed group can, in theory, catch up. India does this with low castes. America does it with certain races.
Now I believe that China has some oppressed minorities of its own. Better beware, or they will take you over in a few thousand years.

David Boxenhorn said:

There are lots of other populations which share the Ashkenazi historical profile, e.g. Parsis, Marwaris, African Lebanese and Asians - is there similar data for them?


David B said:

That being said, I would be sceptical about the idea that selection for high IQ has led to genetic diseases. The average IQ of Ashkanazi Jews is about the same as the professional (gentile) middle classes, who are a similarly selected group, and also largely endogamous (though less so than AJs). Are the same (or similar) genetic diseases also found among high IQ gentiles? If not, why not?


To you both I would add that the population of Anglo-Irish extraction in Ireland, about 4%, fill the niche in Ireland occupied my Jews in many other European countries - Jews are a negligable population in Ireland with a population about 1,500 out of 4 million the last time I saw statistics.
The Anglo-Irish were - and many still are - largely endogamous, but have been under selective pressure for only about 400 years, unlike the Ashkenazim at 1,000 years. Nevertheless thay have produced a disproportionate amount of acclaimed literature in the English language, in the last centuary or so, and continue to be the "captains of industry" in Ireland.
I am not aware of any general tendancy towards any genetic illnesses in this group, but probably this is a result of them not being specifically studied.

Additionally, knowing the process in the case of the Anglo-Irish, it is my opinion that the Ashkenazi Jews may have lost many of their original population, who were on the left side of the bell curve, to the Gentile masses - thus excellerating the positive selection for higher IQ among their group. It would be interesting to test this theory, all it would take would be to proove that Gentile populations who had substantial populations of Ashkenazi Jews in their midst, are of somewhat higher intelligence than average. All I know is that the Dutch (from Holland!), Germans and Poles, have IQ's in the 108-109 range - or about 1/2 a standard deviation (SD) above average?!

But Poles didn't intermarry much with Jews.

There is no gentile population in Europe with an average IQ of 108-109.

As for how common carriers are, here are approximate numbers:

sphingolipids: 11%

DNA repair complex [BRCA1, BRCA2, Fanconi, BLM] : 4%

sphingolipids + DNA repair complex: 15%

sphingolipids + Canavan + familial dysautonomia + DNA repair complex: 19%

sphingolipids + Canavan + familial dysautonomia + DNA repair complex + I1307K + Factor XI: 32%

sphingolipids + Canavan + familial dysautonomia + DNA repair complex + non-classic CAH:= 51%

sphingolipids + Canavan + familial dysautonomia + DNA repair
complex + I1307K + Factor XI + non-classic CAH: 59%

EW,

It doesn't have to be marriage! It is a fact that despite religious, cultural or ethnic taboos, when 2 human populations are in close proximity, thay will interbreed.

Also see this article here on thousands of Ashkenazi Jews becomming Gentiles.

gcochran wrote:

There is no gentile population in Europe with an average IQ of 108-109


OK, maybe I was a bit selective in reporting the above numbers, but if you look at the "Reported Score" pre-adjusted 1979 data here - you will see that West Germany and Netherlands are 109, while Poland is 108 on the Cattell scale - which when adjusted, are Western Germany and Netherlands 107, Poland 106.

Compare these to pre-adjusted Hong Kong is 113 on Cattell (1986), adjusted Hong Kong 107.

Unfortunately Japan and China are not listed as using the Cattell test - which IMO is the best test to take to measure high IQ.

How much has cultural factors been teased out of high Ashkenazi IQ's. I know that Jewish children given up for adoption are often placed with Jewish couples, but are there any studies that have used cross religious adoptions to see if, say, Gentile children raised in Jewish families have higher IQ's than would be expected and likewise, Jewish children raised in Gentile families have lower than expected IQ's?

So, no comments on how easy or hard it would be to make these modifications artificailly, and preferably without the health side effects?

This is gnxp, no?

gcochran,

BTW, I don't mean you to take any of my comments negatively, as I think it's a wonderfull accomplishment to get your paper published, and to start to get people to talk seriously about science, rather than resort to PC BS.

I think there is a correlation between the low US math and science scores and the fact that much of what the US media touts as scientific discussion in not without Religious and Political bias, based on unscientific PC thinking - so that children see science as just "opinion" and not a hard body of research findings, derived from the application of the Scientific Method, in persuit of prooving or disprooving a scientific theory.

So congratulations to you Greg and your colleagues, for helping to re-open the doors of scientific discussion again.

"I know that Jewish children given up for adoption are often placed with Jewish couples, but are there any studies that have used cross religious adoptions to see if, say, Gentile children raised in Jewish families have higher IQ's than would be expected and likewise, Jewish children raised in Gentile families have lower than expected IQ's?"
In the UK, the leader of the opposition Conservatives is Jewish. His potential successors are Rifkind (Jewish) and Davis (gentile-born, adopted by Jewish family). Jews comprise 1% UK population I believe.

The best thing about the hypothesis is that it makes testable predictions. When, and who, is going to do the tests?

Congratulations Gregory Cochran and colleagues.

pconroy: check out Cochran's education piece in this month's _American Conservative_. It's arguable that the correlation between education and test scores is far less than commonly believed.

“The
correlation between verbal and performance tests is about 0.77 in the general population,
but only 0.31 among Jewish children. Differences of 10-20 points have been found in
samples of Jewish children; there is no other group that shows anything like this size
difference.”


Is this evidence for an 'unusual' cognitive profile or merely Charles Spearman's 'law of diminishing returns' at work?

"Greg & Henry can't be everywhere."

Even if I could, I'd be a fool to admit it.

Congrats to all. I'm with DaveG, though: why isn't Greg and Henry's work causing more soul-searching around here about the possibility of undesirable side-effects of efforts to raise intelligence via genetics?

I'm with DaveG, though: why isn't Greg and Henry's work causing more soul-searching around here about the possibility of undesirable side-effects of efforts to raise intelligence via genetics?

Well, regular readers of this blog almost by definition believe the benefits of at least being honest about genetics outweigh the drawbacks. The paper is simply being honest; it does not propose any eugenic program, and indeed it illustrates a drawback of eugenics that many people were previously unaware of.

Greg, Having followed on GNXP the difficult genesis of the article, I wish to congratulate your success. BTW, the article now published is much better than the one you posted a few months ago. As an Ashkenazi, I hope your work will contribute to finding cures to our diseases and make the world less punishing for us. Congratulations again.

why isn't Greg and Henry's work causing more soul-searching around here about the possibility of undesirable side-effects of efforts to raise intelligence via genetics?

rather than address this in detail, i will offer an analogy: why aren't the increased rates of allergy and asthma among modern youth today causing more soul-searching among those who promote the modern lifestyle? answer: the benefits of medicine and city-life outweigh the drawbacks. further exploration leads us back into the realm of values and norms.

As a thought-experiment, suppose we select the top 20% (say)of a western european population for IQ, and eliminate the rest. The selected 20% would then have a mean IQ of about 115. (OK, I haven't done the sums, but you get the point.) They would then breed endogamously, and their descendants, in the absence of further differential reproduction, would have a mean IQ of 115 or slightly less (because the factors behind the high IQ of the original selected group were partly environmental and not inherited).

Question: would the descendants suffer from genetic diseases like Tay-Sachs?

Maybe they would, but I don't see much reason to think so. Some strata of western european societies are already similarly selective, without suffering obvious genetic damage.

They would only suffer from genetic diseases, were the gene pool sufficiently small. After all, in most respects the gene pool of this top 20% of western european population would be very diverse, given the size of the mother population.

would the descendants suffer from genetic diseases like Tay-Sachs?


well, i thought greg and henry already had mentioned somewhere else that the ashkenazi mode might be just one particular selective pathway to high IQ, not the only one? after all, there is the atypical decoupling of visuo-spatial IQ from mathematical intelligence that is not to be found in the gentile population of europe. the phenotype isn't the same, just similar.

They would only suffer from genetic diseases, were the gene pool sufficiently small. After all, in most respects the gene pool of this top 20% of western european population would be very diverse, given the size of the mother population.

i don't think that critique necessarily applies, remember, henry and greg are already rejecting the founder effect hypothesis or genetic drift (a la neil risch). the spingholipid disorders are simply correlated responses to the selection pressure, pleiotropic byproducts whose fitness hit in the context of the ashkenazi environment was more than compensated by the benefit of the higher IQ. one might hypothesize that the greater genetic variation of the european population might allow for more favorable combinations of genes which modify or mitigate the disorders in question, though if henry and greg are right the lack of bottleneck and persistent (though small) gene flow i don't know if that's plausible.

i think it more likely that the high IQ gentiles (that is, jewishly high, but not jewishly plagued with sphingolipid disorders) are simply part of the normal variation caused by the hundreds or thousands of genes of small additive effect that contribute to cognitive function. if you want to take the overclocking analogy further, the ashkenazis simply happened to be in an environment that rewarded obsessive gamers who cranked their machines up to the breaking point to get the most juice out of their systems. others who aren't ashkenazi but still rather good gamers happen to simply have one of those few top-of-the-line machines with shiny new chips by a luck of the draw (or family inheritance), different beasts entirely (well, i actually don't think different entirely, but cognitive phenotype is more than genes alone, the expression of the genes does shape the environment you create for yourself, etc.).

All I'm saying is that I don't see why selecting for IQ, per se, out of the normal range of variation would have genetic ill-effects. But maybe Cochran et al are right in hypothesising that in the particular case of Ashekenazis selection happened to favour some genes with adverse side effects.

I know Cochran et al reject the genetic drift hypothesis, but only as the most plausible mechanism for the Ashkenazic high IQ, arguing that selection was a stronger force. Various genetic evidence do however indicate an early Ashkenazi population bottleneck. I was implying in my "critique" (as you eloquently put it :) that because of this reduced genetic diversity, the strong selection for high IQ produced more fitness lowering side effects because of the more constrained degrees of genetic liberty whereas in the gedanken David Burbridge put forth, these side effects wouldn't be as apparent because, unless the mother population size was very restricted, there would exist more high IQ genes for selection to choose from.

Sorry for the slip, I didn't mean to misrepresent David B's thought experiment. That last "selection" is not of the natural kind, but of the artifical type (eugenic).

Re mechanism: The argument (well known to breeders where there is no argument) goes like this:
In a drastic new environment there is big fitness payoff to IQ. In this new environment there is a payoff to "turning down" BRCA1 to free up early CNS development but at the cost of higher cancer rates later in life. Eventually, especially in a big population, a BRCA1 variant with the optimum activity will show up. Meanwhile carriers of one normal and one broken BRCA1 gene have a big fitness advantage because they have, say, 90% of normal suppression of early CNS development. So the broken BRCA1 allele is favored by selection even though homozygotes for it die. After a long time it would be replaced by the optimum allele but it takes a long time for that optimum allele to show up.

Exactly this argument applies to myostatin in several European breeds of beef cattle: it causes muscle hypertrophy and obstetric difficulties. The muscle hypertrophy is good but the obstetric difficulties require veterinarians and in the wild would have been lethal.

Re the implications of our model for eugenics, yes, big time, eugenics is IMHO a route to disaster. Well understood engineered gene introductions could be fine but eugenics would be almost certain to bring all kinds of nightmares.

Henry

Israeli IQ seems like it should be higher than 94, given the Ashkenazi score of about 112.

If Israel's Sephardic Jews score about 85, along with Israeli Arabs, the Ashkenazim would have to be less than a third of the population to average the 3 at 94.

Anyone know the Ashkenazi/Sephardic/Arab % in Israel?

Ashkenazi Jews are about a third of the total Israeli population, less than a third of kids.

Fast strong selection for _anything_, in _any_ species, tends to cause nasty side effects.

" well understood gene introductions", fancy eugenics, is certainly feasible. These Ashkenazi mutations are first-cut stuff, not optimized at all.

Oh, and razib actually understands what we're saying.

Just Wondering, it's even worse than that. The 94 IQ for Israel was actually averaged from two different studies - one showing an IQ of 98 and the other showing an IQ of *90*. The IQ 98 had a sample size of 180 but the IQ 90 had an enormous representative sample size of almost 1800 people, which might be a larger N than all the American tests showing an IQ of 115 combined.

I suspect that something is very wrong, but I can only advance that as a suspicion. The Israel IQ certainly poses a major problem.

Those Israeli studies are old, aren't they? The 90's Soviet immigration changes everything.

If you want recent data, the psychometric test scores are a good proxy for IQ, I guess.

Well the latter with the big sample was post-90s, but not by much.

I think Flynn showed a Flynn effect and a lack of sex difference in Israel using data from the compulsory military IQ test (which I would think would provide a fantastic source of data), but I don't know what IQ he reported, or why Lynn didn't include it in IQ&tWoN.

Post-Soviet immigration to Israel would presumably raise the mean IQ there, as the immigrants presumably lean toward the higher IQ Askenazi types.

Perhaps a recent Israeli IQ study would shed more light.

mean IQ there

i think it is more relevant to focus on the smart fraction than the mean in such a multi-modal population. consider, (94*.9+115*.1) ~ 96.

Btw, do Ashkenazis have an unusual standard deviation? Would such rapid selection produce an odd SD?

I'm saddened by many of the blogs who have posted this... a heck of a lot of commenters either are saying the IQ is either cultural/environmental or that it shouldn't be studied at all (which was the case over at Moonbat Central)...

But, surprisingly, many, many people aren't taking the news badly, so I guess that's a start.

Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency says:


Although there have been occasional reports of elevated IQ among CAH patients (117), this has not been generally observed. To the contrary, salt wasting patients who suffer hyponatremic dehydration and shock may sustain permanent brain injury with resultant lower cognitive test scores (118, 119, 120). Certain sexually dimorphic cognitive abilities, such as spatial abilities, may be enhanced among CAH girls (121, 122, 123).


Can someone give me references to papers that do demonstrate a positive correlation between non-classic CAH and IQ?

Can someone give me references to papers that do demonstrate a positive correlation between non-classic CAH and IQ?

Nass and Baker, Psychoneuroendocrinology 16, 189-201, 1991. Also New and Wilson, PNAS 96:12790-12797, 1999.

Non-classic CAH is a real mild form--the enzyme is still fairly active.

Henry

Hmmm, Henry Harpending reponds:


Nass and Baker, Psychoneuroendocrinology 16, 189-201, 1991. Also New and Wilson, PNAS 96:12790-12797, 1999.


I just tracked down the on-line version of the PNAS paper by New and Wilson. I skimmed it and searched for IQ and cognition.

AFAICS, it does not mention any correlation between IQ and non-classical CAH. IQ does not appear in it anywhere, and the word cognition is mentioned only once in relation to post-natal checks of patients treated in-utero for CAH to see what effects the treatment might have had on cognition.

I will read it more carefully now, and track down that other article.

Well, I'm not going to find that paper by Nass and Baker online, it seems.

Here is the abstract: ScienceDirect wants $$ for the pdf:

Review

Androgen effects on cognition: Congenital adrenal hyperplasia

Ruth Nassa, b, Corresponding Author Contact Information and Susan Bakera

a Department of Pediatrics, New York Hospital - Cornell University Medical Center, New York, New York, U.S.A.
b Department of Neurology, New York Hospital - Cornell University Medical Center, New York, New York, U.S.A.

Received 10 October 1989; revised 21 November 1990. Available online 22 March 2003.


Abstract

Cognitive studies of congenital adrenal hyperplasia (CAH) patients have revealed (1) the presence of an IQ advantage in patients, siblings and parents due to socioeconomic status, genetic, hormonal, or other factors; (2) an IQ disadvantage in salt wasters compared with simple virilizers, probably due to early brain damage secondary to salt-wasting crisis; (3) a possibly increased incidence of learning disabilities, particularly in female patients and particularly for calculation abilities, due to disease-related early androgen exposure; and (4) a possible post-pubertal spatial advantage in CAH women, also due to early androgen exposure.

Corresponding Author Contact InformationCorresponding author. Address correspondence and reprint requests to: Dr. Ruth Nass, New York Hospital, 525 East 68th Street, , New York NY 10021, , USA.

Well, the Nass & Baker paper would appear to be this one:

Androgen effects on cognition: congenital adrenal hyperplasia.

Here is a link to it in Pubmed.

The abstract says:


Cognitive studies of congenital adrenal hyperplasia (CAH) patients have revealed (1) the presence of an IQ advantage in patients, siblings and parents due to socioeconomic status, genetic, hormonal, or other factors; (2) an IQ disadvantage in salt wasters compared with simple virilizers, probably due to early brain damage secondary to salt-wasting crisis; (3) a possibly increased incidence of learning disabilities, particularly in female patients and particularly for calculation abilities, due to disease-related early androgen exposure; and (4) a possible post-pubertal spatial advantage in CAH women, also due to early androgen exposure.


While it alludes to a correlation between IQ and patients it seems to imply that it might be due to heredity and other factors ... Will have to get hold of the printed article.

Ahhh, I have access, but couldn't find the PDFs. I have tried forwarding it to me, but we will see if that happens.

i just read the full almost 40pg PDF version. Brilliant paper. Perhaps as importantly, it's great the NYT and the Economist decided to publish.

My guess is that it's not as politically incorrect as some, like Pinker, would suggest because the thrust of it is that Jews are smarter due to their genes. Careers normally get trampled on only when somebody is ascribing an attribute to a group that the rest of us perceive as the 'wrong' attribute to have. Some of the high IQ liberals will understand the implications of this, but most won't be able to put 2 and 2 together on a paper this technical. Again, fantastic.

I'm no expert on Ashkenazi history, but surely the founding population of the Ashkenazis in medieval times must have been small relative to the European population at that time, which itself was very small relative to modern populations.

So I'm puzzled as to how there can *not* have been a pretty narrow bottleneck at some point in Ashkenazi history. If Greg & co's technical arguments against a bottleneck are watertight, I suppose we must accept that, but I'll be interested to see what other experts say on this point.

In a bottleneck, the effective population size becomes small enough to significntly affect gene frequencies. It's not black or white, bottlenecked or not bottlencked: it's a continuous variable. You have to look at the integral over time of the inverse of the effective population size - a tiny population for one generation has the same effect as a ten-times-bigger population persisting for ten generations.
Bottlenecks decrease genetic diversity. Bottlenecks increase genetic distance: the gene frequencies change randomly and become more different from other populations than they originally were.
Consider the Samaritans. Their nuclear-gene diversity is something like 80% of normal, and they are now genetically distant from everyone: but here we're talking about a strong bottleneck, a population down to something like a hundred or a few hundred for a number of generations.

The Ashkenazi do not exhibit reduced nuclear-gene diversity. They do not exhibit increased genetic distance from other populations: in fact, they are pretty close to mixed Europeans: the Ash-Eur genetic distance is about a third as big as the typical distance between Middle Eastern and European populations.
That means that there has to have been significant European admixture - which admixture would reduce the effect of any bottleneck.

You could look at the diversity of y-chromosomes: the effectve population size is four times smaller, and thus y-chromosome diverity is a more senstive measure of bottlenecking. But there is no reduction in y-chromosome diversity.

A few non-scientific observations & one question.

I can't discount the cultural aspect for the same reasons Benjamin brings up in "Moonbat central"--what about all the great Sephardi sages of medieval Spain? Razib, Ashkenazi Jews haven't been differentiated for "30-40" centuries.

Jason, the reason this makes Jews uncomfortable can be found here:
http://www.whiterevolution.com/a...hey-were- stupid

About gypsies. They make amazing musicians and linguists. In Russia, they are among the few people who under Communist isolation somehow managed to be multilingual. I heard this personally. They invented a style of violin playing that exceeds the classical repertoire in difficulty, the only group that I know of that has done so.

Gcochran: You ask, "Guess how?" I can't. How?

shkenazi Jews haven't been differentiated for "30-40" centuries.


that's why i said generations :)

duh. I guess I make up for all those smart ones....:)

but even so, is Ashk. history really 900 years as a separate & distinct group? I thought it was really 300 years, starting from 16 century Poland. Shabtai Tsvi (Sephardi) married a girl from Poland and it wasn't a big deal. I don't think there was such a distinction then.

but even so, is Ashk. history really 900 years as a separate & distinct group? I thought it was really 300 years, starting from 16 century Poland. Shabtai Tsvi (Sephardi) married a girl from Poland and it wasn't a big deal. I don't think there was such a distinction then.


if you jews were a historically conscious people we would know, wouldn't we? in the jewish mind raphael patai notes that jews really didn't take a particular interest in the non-religious aspects of their development and historical progress so a lot of these questions are up in the air, though of course we all know all that jazz about what rabbi said what about obscure commandment #314 or whatever in what year.

but if you looked at the alleles in both populations you could probably ascertain the extent of cross-fertilization between the two groups, 900 years is enough for mutations to happen. you might even be able to gauge it to some extent by the differences in the form of hebrew used by both groups.

Yes, 900 years is enough for mutations to happen.

But 300?

I can't discount the cultural aspect for the same reasons Benjamin brings up in "Moonbat central"--what about all the great Sephardi sages of medieval Spain?

The threads I've seen are filled with these kinds of points.

They're all irrelevant. Either the prediction of heterozygous carriers of the disease mutations have enhanced IQ compared to otherwise genetically similar people will prove to be true, or it won't. If it is true, the only conceivable reason is effective selection for enhanced IQ.

That's why the paper is such a big deal -- it stands to eliminate the plausible deniability that has characterized this subject for decades. Your hypothesis may be true as well, but it's impractical to test. In contrast, we'll KNOW if this one is true or not.

Jason, the reason this makes Jews uncomfortable can be found here: [white nationalist link]

I sympathize with your sentiment. But the Blank Slate lie has been partly responsible for the deaths of over a hundred million people via communism. We need to move on to a less destructive way of preventing pogroms. (I understand that Amy Chua studies the issue in World on Fire, but I have not yet read it myself.)

prediction of heterozygous carriers of the disease mutations

Correct that to "prediction that heterozygous carriers of the sphingolipid disease mutations".

Incidentally, the Economist and the NYT misreport the hypothesis as "all Ashkenazic disease mutations are caused by selection for intelligence", when the paper specifies that a few diseases do probably have other causes.

The Ashkenazim show up first in the historical record in the Rhine valley, during Carolingian times (although some may have been there earlier)
They expand for a while (France, Germany, England) and then are mostly expelled: they then move east. First Austria, Bohemia, Moravia, then the Polish-Lithuanian Commonwealth. The Ashkenazim and the Sephardim have taken separate paths for well over a thousand years. There was a little mixing, but not much.
And that's easy to see today: the Sephardic Jews today don't have those Ashkenazi mutations, mutations which are mostly over a thousand years old (judging from linkage disequilibrium).

Greg, the Jewish population of E. Europe exploded during the 17th century. I've read that this couldn't have happened by natural increase alone. Where did these people come from? Could they have come from judaizing sects that were incorporated into "the Jewish people"? Who on earth would have known, as there wasn't a centralized rabbinic authority to say who wasn't and was Jewish?


Is it possible we might be overrating the extent and thorough-going nature of anti-Semitism?

diana, well, clearly there was admixture between jews and non-jews going on (written in the genes as they say), though my historical reading in western europe suggests that judaizing would get you into deep shit quickly and not be good for your prospects of having kids if you kept your balls from getting burnt...but in the boonies of eastern europe where the peasants might never seen a priest before the counter-reformation, who knows? but i also don't see why natural increase couldn't work it, is it because disease would have killed off too many of the children?

anti-semitism was certainly a problem in the past, see the rhineland "jew roasters" of the medieval period, but i think it is possible that we back-project the germano-racialism prevelant around 1900, and that led to the formulation of zionism by herzl because of his despair about jews ever being accepted, too much.

Jason, the reason this makes Jews uncomfortable can be found here: [white nationalist link]

well yeah, that's true enough, but of course the haters will hate no matter what the facts are, that is, unless they can lead you around with a leash and debase you they won't be happy. after all, the nazis exterminated the sephardim of greece (along with the native pre-sephardic jews) no matter that they had little to do directly with the inner demons of hitler rooted in his experiences with the viennese jewry.

The Jewish population of Eastern Europe increased rapidly, all right. Up until about 1650 immigration of western jews was a significant part (exact extent as a function of time unknown). After the Chmielnicki massacres of 1648-49, immigration pretty much stopped and population growth slowed.

Was there something mysterious and/or impossible about Jewish population growth during this period? Nope. Is there any reason to think that a lot of outsiders joined? No.

I think it's riciculous the way Jews don't want to be singled out for being smart. Sure, some resentment may result from recognition of this fact, but it will almost certainly be outweighed by admiration. The time of pogroms is past - especially in America, where it never existed in the first place - and, as Razib said, the haters will hate regardless of the facts.

Jewish population of E. Europe exploded during the 17th century

The population of England (including descendents outside the country) also exploded during this period.

Don't Parsis also have high IQ's and genetic disorders?

The population of England (including descendents outside the country) also exploded during this period.

yes, but the population of poland-lithuania did not, in particular the gentile population of poland-lithuania. ergo, the judeo-induced demographic terror that haunted the rhetoric of some anti-semitic nationalists...after all, everyone knows how prolific jews are! galicia is crawling with them!

Don't Parsis also have high IQ's and genetic disorders?

genetic disorders, yes, high IQs, well, i don't think they've been psychometrically evaluated in the same way. in relation to their population though they might be even more impressive than jews in the context of south asia (though the mean IQ of the substrate is likely lower in south asia than northern europe). but note that the parsis are in sharp demographic decline (>60,000 and counting lower, lower....) and from what i gather they are rather inbred.

Guys, I'm not really opposing Greg's thesis. It's interesting. Jews consistently score highly on IQ tests and there has to be some explanation.

I just mentioned the population thing because I remembered a NY Times article that mentioned something about an unexplained Jewish population surge in E. Europe.

And here it is:
http://sciwrite.org/glj/ articles...es.yiddish.html

"Arching over these questions is the central mystery of just where the Jews of Eastern Europe came from. Many historians believe that there were not nearly enough Jews in Western Europe to account for the huge population that later flourished in Poland, Lithuania, Ukraine and nearby areas."

We don't really know where Yiddish comes from. Paul Wexler of Tel Aviv U thinks it is a re-lexified slavic tongue. In light of Hammer et al: http://www.racesci.org/in_media/ ...nyt_May2002.htm

might he not be right?

might he not be right?

there is weird shit coming out of the jewish historical genetics (the bizarro lineages in the levites with turkic affinities?). so there could be a lot of weird things going on. who knows. but greg has spent a shit load of time studying this topic, and human populations do have the potential to grow pretty fast without constraints.

Isn't Yiddish basically German with a smattering (schmuttering??) of other vocabulary? Schmuck, mensch, and other familiar Yiddish words are just German, though the meaning may have shifted. E.g. schmuck is German for 'decoration', and we can see how the meaning may have shifted from 'decoration' to 'penis' (one of its Yiddish meanings) to 'fool'.

Diana,

Ashkenazi Jews also were largely exempt from military service in the Polish-Lithuanian Commonwealth, so that has got to positively affect their numbers.

Plus the cyclical famines of the era, would weigh more heavily on the serf class than on the Jewish mercantile class, or the Szlacta (nobility).

Once the potato was introduced, the population of this area, and other colder more Northern areas of Europe exploded.

Plus they did get an influx from Khazar converts, but that was much earlier in their history.

I also suspect that those Gentiles who wanted to get into the lucrative banking business, and were wealthy enough not to be concerned about being shunned or otherwise by their peers, simply converted here and there to Judaism - this of course is just a supposition on my part, but not without precedent.

David B.

Yes, Yiddish is a dialect of Hoch Deutsche (High German), with a smattering of Hebrew and later Slavic loan words.

David,

Paul Wexler(linguist, Tel Aviv U) believes that no matter how many German words there are in Yiddish, that the deeper syntactical structure reveals a Sorbian origin. He claims to have demonstrated this in several books:
http://www.amazon.com/exec/obido...=Mozilla- search

I think his theories should not be dismissed out of hand and deserve further scrutiny. They may well match up with Hammer, et al.

Diana,

That's an interesting link to the theory that Sorbian is the root language of Yiddish, as Razib and maybe others had postulated a theory of maternal admixture of Sorbs into the Ashkenazim gene pool, based on mtDNA analysis, some time ago.

It's also interesting that the Sorbs were originally a Slavic/Alan (Iranian) mixed tribe, see here and here

continued...

The Alans survive today as the Ossets, and both Alan and Ossets would have been followers of Zoraster, and this has antecedants for the Jewish religion also, see here and here

OK, last question. Sailer says, "people with one copy of the genes that cause the Ashkenazi sphingolipid diseases should have higher IQs than their siblings who have no copies."

Are there non-Jews with a copy of these diseases? Sephardic Jews with one copy?

If so, let's test them, as well, and see what we get.

oops, I mean a copy of the genes...

Are there non-Jews with a copy of these diseases?

quebecois tay sachs.

Razib,

"it is more relevant to focus on the smart fraction than the mean in such a multi-modal population. consider, (94*.9+115*.1) ~ 96." (Israeli IQ)

I think the Smart-Fraction Theory of IQ better explains national GDP than any other measure I've seen.

Also, seems like both the smart fraction over 106 and the mean Israeli IQ of 94 would rise via immigration from the former USSR with 1/3 or more Ashkenazim. Since I believe the Ashkenazim originated as a trading empire in southern Russia who converted to Judaism around 800 AD, presumably many of their descendants would have still been in that area to emmigrate.


Jason Malloy,

"do Ashkenazis have an unusual standard deviation? Would such rapid selection produce an odd SD?"

If someone answered this I missed it, but it would help to locate the edges of that IQ bell-curve.

The Ashkenazim have at most a little Khazar ancestry. They're middle-easterners mixed with europeans, mostly western europeans. If you look at the alleles, it's reasonably clear. You're not going to see a lot of alpha-thalassemia or familial Mediterranean fever among Khazars.

I do have to wonder about the assertion that the "rabbi marries the merchant's daughter and has many kids" pattern is insignificant just because of the small percentage of the population involved. My back-of-the-envelope calculation suggests that the magnitude of the deviation from the norm is enough to compensate.

Specifically: if rabbis have average verbal IQ 2 SDs above the population norm, comprise 1% of the population, but have 4% of the children (this just corresponds to double, not quadruple, reproductive success, since they're only responsible for half of each child's genes), this effect alone raises population mean verbal IQ by 0.24 per generation (assuming narrow-sense heritability of 0.8).

Don't "persecution" and "selection pressure" mean the same thing if we disregard any embedded value judgments?

If there is a scientific distinction between these two terms, how can we identify it?

doj, i find the idea that rabbis were 2 stds above the IQ a bit much. and 0.8 heritability probably too.

Don't "persecution" and "selection pressure" mean the same thing if we disregard any embedded value judgments?

semantics, semantics, but i don't think so. selection can reshape the extended phenotype and create its own fitness landscape. after all, once empancipation ensued jews didn't go to a farming (it's hard enough to get them to do it in israel when there are incentives).

I don't believe the 2 sd difference, the 1% of the population, the doubled reproduction, or the 0.8 narrow-sense heritablity. Other than that you're fine.

I don't believe the 2 sd difference, the 1% of the population, the doubled reproduction, or the 0.8 narrow-sense heritablity. Other than that you're fine.

Fair enough, those are probably all overestimates, so the actual impact will be exponentially smaller. I am curious what the best available estimates of these parameters are, though. If the overestimates are all by 25%, for example, 0.24*(0.8)^4 = ~0.0983 per generation is still enough to matter. (I'm quite confident that your primary thesis is correct, I just want to understand why you seem to think Wiener's theory doesn't contribute to the picture at all.)

From Bashavis Singer's biography, 1% of the population sounds like the minimum, maybe more than 2%, but the other numbers are way too high.

The rabbi-marrying-the-merchant's-daughter theory sounds not implausible to me, but I must admit I'm not aware of any historical evidence for it at all. Somebody should see if they can pull together a case for it.

Since this thread has been up awhile, I'll try once more before it expires.

Concerning methodology:

1) Were Ashkenazim self-identified, or determined by genetic analysis.

2) I've heard that Prof Lynn set Ashkenazim IQ at 107, as opposed to higher studies claiming 117, which begs questions regarding evidence.

3) Do we have a standard IQ deviation for the Ashkenazim?

4) I wish to congratulate Messer's Cochran, Harpending, and Hardy on their personal courage in broaching a societal taboo, and doing so with professional distinction. Cheers!

There is, in my pesonal experience, a phenomenon of dropping out of the Jewish framework. In current American Judaism it may be around 40%. It existed in every generation. I can say that in my case - I am talking about the Buenos Aires Jewish community 30 years ago - the cut out point was the university. Those boys who did not follow a university career and did not became middle class professionals, dropped out of the community. Simply, they did not feel well with the successful majority. They were also ashamed. They felt more at home in the less demanding gentile society.

There was also the phenomenon of dropping out of the excelling Jews. Those who arrived to a position where the reward for cutting their Jewish links became so high, that they did it almost invariably. Comes to my mind the German poet Heinrich Heine, to achieve his diploma of lawyer, he had to submit his baptism papers. He said that baptism was his passport to European culture. The father of Marx was baptized for the same reason. In Argentina, to be accepted in the power clubs like the Circulo Militar you had to abandon Judaism. Many did.

There is a selection, but I cannot decide if it is eugenic. I think that in contemporary Judaism the overall effect is dysgenic. But I can imagine situations where this dropping out was highly eugenic: when Jews monopolized a rich niche in the economy, like in England under Norman conquest. Jews who failed as financiers would have to find subsistence as farm hands, as such they could not belong to the exclusive community of the top financiers of the realm. As said, I think that the current situation is highly dysgenic, not only in America but also in Israel.

PS: There is an old book, "The Carpenter Years", that treats very nicely this dropping out issue.

This is rather a late and superficial comment, but I think the Sephardic/Ashkenazi distinction may be overstated. Modern Sephardic Jews are mainly from north-african or middle-eastern countries, are often poor, and apparently have lower measured IQs than Ashkenazis. But is this a genetic or environmental difference?

In contrast, in Western Europe the Sephardic Jews are (or were) an educated elite. Many of the famous Jewish scholars (Spinoza, Ricardo, etc) came from the Sephardic community.

There is also the case of the Italian Jewish community, who if I recall correctly are/were neither Sephardic nor Ashkenazi. They were also a commercial and scholarly elite.

So the assumption that the Ashkenazim stand out as intellectually superior to other Jews seems to me very doubtful, in a historical context.

An argument against the influence of surrounding culture on Jewish intellectual performance is that secular Yemeni Jews seem to be more successful than Moroccan Jews in Israel. This, despite the fact that they were lifted out of Third World conditions within the space of a few years, while the latter enjoyed the benefits of French culture under colonial rule.

Razib, would you care to take a stab at the non-J and non-AJ carriers of storage disease genes issue? *If* they test out with higher IQs, then does this suggest a...pattern? If so, what does it prove, because isn't it correlation? (not causation)

Melnorne,

But isn't it the case that genetically Yemeni Jews do not closely match other Jews, and so much of their population is believed to be converts to Judaism - although centuries ago?

Talking about Yemeni and Moroccan Jews' intelligence is very non PC in Israel. I dont want to remember the clinical name of the the category of those under IQ = 75 but Ethiopian "Jews" coming to Israel qualify. I think an irresponsable social experiment is being done in Israel, putting together two different ethnic groups separated by an average difference of 50 IQ points (!).

Jaimito,

Right, weren't the Ethopian (Falasha) Jews recognized by some chief Rabbi as the lost tribe of Dan, only to have DNA studies show a couple of decades later that they were barely related to Jews if at all?!

In the short term, the Falasha immigration is a huge benefit to all involved. They get out of Israel, Israel gets laborers who don't want to kill them and PC credit with the US left and a defense against the claim that zionism = racism. In the long term, well, when your surrounded by people trying to kill you, focus on the short term and remember that the oil won't last forever.

Right, weren't the Ethopian (Falasha) Jews recognized by some chief Rabbi as the lost tribe of Dan, only to have DNA studies show a couple of decades later that they were barely related to Jews if at all?!

From a Jewish point of view there is no contradiction at all. Judaism does accept converts, you know. (Same goes for Ashkenazis, by the way.)

Michael: The Ethiopians are wonderful people and I, for one, am glad they're here.

One thing I don't understand: If 59% of Ashkenazis are heterozygous for a known genetic disorder, why don't I hear more about the issue? I know lots of Ashkenazis, and even though the sum of the squares is a lot less than the straight sum, I would imagine that it would still be noticeable. I know one family that has a problem with dysautonomia, and that's all.

David, 59% are heterozygotes for at least one of the disorders, not for one single disorder.

pconroy: re Yemeni Jews, no, they resemble other Jews w/respect to patrilineal markers. It's the same story on the maternal side: local. The Ethiopians are completely unrelated to other Jews genetically.

I found it amusing that the rabbis decided they were descended from the tribe of Dan, as some biblical scholars conjecture there was always something rather foreign about the Dan, and this this origin of this tribe was with "the Danae," a division of the Sea Peoples who settled in Philistia. (ie they were Philistines.)

David, 59% are heterozygotes for at least one of the disorders, not for one single disorder.

I am aware of that. Suppose there are 60 genes, each with a frequency of 1%. The number of couples with problems would be:

60 * (0.01)^2 = 60 * (0.0001) = (0.006) = 0.6%

That would be noticeable - and I think that there are less than 60 genes in that 59%!

That would be noticeable

unless there is a strong hit on viability of the fetus which purges those have have shitty penetrance of the disease and all that. the higher miscarriage rates of basques due to rh-/+ incompabilities was simply written off as congenital sickliness before modern medicine....

I think an irresponsable social experiment is being done in Israel

Mmm. It'll be interesting to see how those tribals from Myanmar ( 'Tribe of Manasseh' ) perform.

Also re : heritability of intelligence, it seems that those Ethiopians who are particularly successful often report coming from a relatively privileged background. Sons and daughters of village leaders and the like. My own opinion of them skewed positive when I was a soldier ( and it still is, really ), but the crime rates tell a different story.

often report coming from a relatively privileged background. Sons and daughters of village leaders and the like

There are like I am first cousin of Rothschild.

But I have to agree with Michael Vassar above. Lots of PC credit. Go the supermarket and buy something with it!

David, it is noticeable but only if you actively look for it. I am sure that in your daily life - except if you work in the University of Tel Aviv - Tel Hashomer Genetics Department - you dont meet homocygotes for the diseases in question. Having a relative dead of a terrible disease or bad genes in the family does not come up in water cooler talk.

Weren't the Ethopian (Falasha) Jews recognized by some chief Rabbi as the lost tribe of Dan, only to have DNA studies show a couple of decades later that they were barely related to Jews if at all?!

True. Israel has TWO Chief Rabbis, not one, and they hate ex officio each other. Recognizing the Ethiopian Falasha community as pertaining to the tribe of Dan, the non-Ashenazi Chief Rabbi acquired automatically 150,000 voters and followers. DNA studies are not mentioned in the Talmud and are irrelevant, and in general, Judaism has a liberal attitude toward genetics. In fact, it is known that whole communities were in the past converts, you can know them because they have no Cohens nor Levis among them, but having lived as Jews for many generations and suffered for being Jews, the question of genetic origin is no more relevant. And with the general process of intermarriage going on in Israel, in each family there are people from everywhere.

No one knows how Jews arrived to the African highlands, but the Ethiopian Jews are known to exist for at least 1,500 years, they maintained a very isolated Jewish kingdom in the inaccesible Ethiopian high valleys, some of them occupied a special economic niche as builders of forts and churches, they were hated by their countrymen, who accused them of cannibalism and of not being real Ethiopians (Falasha means stranger).

To Melnorme: As a reserve soldier, any relief after 30 days of guarding a remote army post is more than welcome, no questions nor DNA sample asked. BTW, I also like them.

Jewish identity has never been solved, and no one has the right to say he is more of a Jew than the next fellow. Even Christians started as a Jewish sect, so some original "Jewish" genes must be lurking in most Christians. And Muslims too, since the Prophet made war and disbanded the Jewish tribes of Mekka and "assimilated" them (it is in the Koran).

Associative mating has been going on heavily in the US and Western Europe for awhile now, and I've certainly heard friends muse about whether children of two very smart parents tend to have more problems mentally or physically. I'm curious if there's any data about this.

There are obvious selection effects here, since smarter, better-educated families will be more likely to recognize developmental problems and try to get them treated. I'm just curious if there's any data along these lines.

--jmk

Regarding the Israeli IQ, the Ashkenazi percentage of kids must be much higher than one third. The Haredi are breeding like crazy, and the family-type perks they have historically extracted from the government are nothing to sneeze at.

Also, the Iraqi Jewish IQ, at least anecdotally, is rather low. The reports sent bacck to Israel from Israeli Zionist agitators (sent to I