My (non-Jewish) father told me about this story over the weekend. I wasn’t surprised to see PZ critiquing it.
Here’s the argument, as quoted by PZ:
Gregory Cochran has always been drawn to puzzles. This one had been gnawing at him for several years: Why are European Jews prone to so many deadly genetic diseases?
Tay-Sachs disease. Canavan disease. More than a dozen more.
It offended Cochran’s sense of logic. Natural selection, the self-taught genetics buff knew, should flush dangerous DNA from the gene pool. Perhaps the mutations causing these diseases had some other, beneficial purpose. But what?
At 3:17 one morning, after a long night searching a database of scientific journals from his disheveled home office in Albuquerque, Cochran fired off an e-mail to his collaborator Henry Harpending, a distinguished professor of anthropology at the University of Utah in Salt Lake City and a member of the National Academy of Sciences.
“I’ve figured it out, I think,” Cochran typed. “Pardon my crazed excitement.”
The “faulty” genes, Cochran concluded, make Jews smarter.
I had basically the same reaction to my father’s summary of the article that PZ did, though of course PZ probably said it better than I did off the cuff in the car:
My first answer would be to consider that they are a sub-group isolated by a history of bigotry from the outside, and strong cultural mores from the inside that promote inbreeding. These are variations amplified by chance and history…
Mr Cochran’s flaw is in his premise. There is no reason to assume that the frequency of every allele in a population must be the product of a selective advantage.
Ashkenazic Jews may simply be susceptible to many genetic diseases because those diseases didn’t sufficiently interfere with our breeding that they were erased. They don’t have to have given us a benefit. That’s not how evolution works.
My other question about the article revolves around the idea of “smarter.” There are certainly a lot of cultural ideas floating around that Ashkenazic Jews are somehow smarter than people of ethnicities — and these are old enough that when Goddard tried to push his flawed IQ tests as proof that Aryans were smarter than other peoples, he specifically mentioned what he felt were myths of Jewish intelligence.
But what is this coming from? Do we really have data to prove it? Remembering, of course, that minor fluctuations in IQ tests are easily explicable because of the ways in which upbringing informs interaction with standardized tests, I’m unwilling to take the 7 point difference they find between Ashkenazic Jews and other ethnicities too seriously. However, if — if — Ashkenazic Jews are performing meaningfully higher than average on IQ tests (in a way that suggests they actually have a higher narrow-and-problematic-thing-that-IQ-measures rather than just a better facility with standardized tests), have we ever done anything to try to confound environmental factors? Why does it have to be genetic?
When I first went to college, I attended a school with something like a 40% Jewish student body. I hadn’t been around so many Jews before. Many of my childhood friends were Jewish, and of course I’m ethnically Jewish, but I hadn’t had the experience of being in social groups that were predominantly Jewish.
I remember commenting to a friend of mine who had attended a Jewish private school in Chicago that my experience was that Jews were smarter. The Jewish friends I’d had in high school, I said, were all intelligent and academically capable. Therefore, I concluded, Jews were smarter than average.
My friend lowered a skeptical gaze at me, and said, “Believe me. Jews are just as dumb as everyone else.”
I have to agree with your friend. I lived in a neighbourhood where nearly everyone was Jewish. I assured you that there were just as many dumb kids doing dumb things in my high school classes as anywhere else. On the whole “smarter” thing, however–the Chinese are the new Jews in that department. If only it were true it would bode hope for humanity given the proportion of the human population that is East Asian. Alas–I think it’s just so much stereotyped bunk.
As someone who, the other day, thought she’d left her keys at the coffee shop after she let herself into her apartment, I also agree with your friend.
There are also several genetic disorders which afflict the Amish disproportionately.
As for the smart/dumb thing, one thing I’ve noticed across many ethnic groups is that the “best” go out into the wide world, the “worst” tend to stay close to home and develop social ties within their ethnic community.
That he would put this argument forward seriously makes me feel embarrassed for Cochran.
Okay, it’s not unheard of for a some alternate expression of a gene linked to a disease to confer a benefit (sickle cell/protection from malaria), but just about every inbred population, whether inbred for cultural reasons or because of geographic isolation, has higher incidence of certain diseases. Selecting against these is, like you said, not how natural selection works. The diseases don’t kill enough people for selective pressure to come into play, and too many other factors are driving mate selection.
And something like intelligence is so complex and so culturally determined that to pick that as the benefit conferred by these genes is really stretching.
Two demographic words: Population Bottleneck
Anthropology word: Endogamy
Two genetics words: Founder Effect
The Ashkenazic Jewish population was highly endogamous at the time of and for several generations after the population bottleneck, so any non-lethal genetic changes stayed within the population. Better to marry a Jew with some familial history of heritable disease, than not to marry at all (or marry a Gentile and disappear into the majority population). The population recovered and had an increase of some types of genetic disease, decrease of other types. It is not a “Jewish” phenomenon, but a phenomenon of isolated small populations.
I was more embarrassed for Harpending. Cochran, after all, is neither a geneticist nor an anthropologist. Harpending, OTOH, is an anthropologist and didn’t raise the obvious objections. Kinda sucks when you open your mouth to reveal how bad you are at your job.
This is “science” in the sense that it is sciency sounding and of the poorest quality.
Cochran, after all, is neither a geneticist nor an anthropologist.
Except that neither am I. And neither are you (I think). And neither is Mandolin (I think). Of course, we are Jewish, which makes us … smart! ;)
“Anthropology word: Endogamy”
Well, I thought it was generally accepted that no culture was genuinely endogamous, except inasmuch as they claim to be endogamous (Just as Americans aren’t really monogamous, we’re serial monogamous. We just claim to be monogamous.). The idea that Jews have sexually kept to themselves is pretty well debunked — there’s a lot, lot, lot of genetic mixing. So I’m not sure how much comparisons between Ashkenazic Jews and Hapsburgs (which isn’t exactly what you’re saying) are valid in reality, so much as in the perception that people wanted to have of Jewish reality.
Chingona — I did undergrad in anthropology, so I’m a little bit better versed on the basic theory than average… enough to call bullshit on a lot of people’s rambling, anyway. :-D
Bottlenecking events & populations were covered in intro to genetics. Or was it evolution? Either way, doesn’t matter. Someone had a critical thinking fail.
Whit,
My university combined it all into one course called “Population Genetics, Ecology, and Evolution”. It tied things together quite nicely. I can’t imagine anyone not flunking this sophomore level course if they made the sort of assumptions these two did. It’s inexcusable.
What’s even more interesting is that before WWI, Jewish people were scoring LOWER than other ethnic groups (with the exception of blacks), leading white supremacists to conclude that Jewish people were genetically INFERIOR to other ethnic groups.
It was only after the Jewish population in America assimilated after the waves of immigration in the early 20th century that their IQ figures began to creep up.
Tay-Sachs was an example in my high school biology textbook. It seems to be like sickle-cell anemia, but with tuberculosis instead of malaria. One copy of the gene protects against tuberculosis, two kills you dead.
Granted, the science may have been refined/updated since high school, but it’s not a completely unknown hypothesis.
In the case of “Jews, just as dumb as everyone else,” I present … Exhibit A:
“Jewish people were scoring LOWER than other ethnic groups”
Nope. Higher, about the same as now. As for Jews being just as dumb as everyone else, why not look at the statistics? They do not support your position. Not at all.
By the way, you don’t need to feel embarrassed for me. Jim Watson liked the idea. Stephen Pinker thinks it reasonable, as does Jim Crow (one of the founders of American population genetics.) Leigh Van Valen liked it – offered to publish it in his journal.
Lastly, where does anyone get this idea that it would be hard for a physicist to learn population genetics?
Dude, please. There are plenty of stupid Jews. What Jews do have is a culture that promotes literacy and values intelligence – and somebody with average ‘natural’ intelligence who applies himself to learning is going to seem ‘smarter’ than somebody who doesn’t.
How the family raises a kid has no effect on adult IQ: the IQ of an adopted kid is no more similar to his siblings than that of someone randomly picked from the general population. No correlation with the adopted parents. There is a noticeable correlation with the IQ of his _biological_ parents, though.
Along the same line, identical twins raised in different families have extremely similar IQs – and have similar personalities, etc.
Experimentally, the cultural influences you cite don’t matter. I’m surprised how few people know this.
Let’s ignore for a moment that “IQ” is not a magical, accurate and perfect rating of intelligence: you can’t seriously be arguing that home environment has no effect whatsoever on IQ scores, particularly in children. You know, the group that IQ was designed to measure?
Home environment has some impact on childhood intellectual development. Higher SES families tend to produce higher-IQ children.
“How the family raises a kid has no effect on adult IQ” is not quite the same thing. From what I understand, within the boundaries of what we consider acceptable and normal parenting, most of the choices made by parents in fact have no measurable impact on the IQ of their children, once those children are adults. Heritability and SES account for pretty much everything we observe.