The biological distinctiveness of ethnic groups is fraught scientific territory, but a new study plunges into the debate by theorizing that the high intelligence of Ashkenazic Jews is in the genes.
The study, which will be published in the upcoming issue of Journal of Biosocial Science, argues that natural selection favored more intelligent Jews during 800 years in Northern Europe, when Jews were genetically isolated and intellect was the most important quality for Jewish survival and biological fitness. As genetic evidence for the natural selection, the authors point to what they say is a complimentary group of genetic diseases prevalent among Ashkenazic Jews, including Gaucher disease and breast cancer.
The new study received laudatory coverage in the magazine The Economist and an evenhanded reading in The New York Times. But geneticists who study the Ashkenazic Jewish population are raising hefty questions about the methodology and findings. They say each step of the team’s multilayered argument is contentious — down to the notion that what is considered intelligence today would have made medieval Jews better at generating money and finding spouses.
The study also flies in the face of contemporary conventional wisdom about the source of high achievement among Jews. In the wake of the Holocaust, historians say, Jews have looked to culture rather than science for answers about Jewish behavior and achievement.
“This study upsets the American Jewish narrative about ourselves — that our ancestors came over, and by dint of hard work and drive, made us into a model immigrant group,” said University of Florida professor Mitchell Hart, the author of the book “Social Science and the Politics of Modern Jewish Identity.”
“The genetic determinist argument would in some way take away from that,” Hart said.
On many levels, biological determinism serves as the foundation for the new study.
“People invoke culture a lot, but in behavior genetics they can’t find that it’s really so,” said Gregory Cochran, who authored the study with a professor and a graduate student in the University of Utah’s anthropology department. “It’s something that people would like to be true, because it would make problems easier to fix.”
Already the Utah study has attracted national attention, and won tempered praise from high-level cognitive scientists such as Steven Pinker, in a recent New York Times article. But the authors of research on Jewish genetic diseases — on which the new study is based — were quick to question whether the connections made in the new study are sound.
“The only controversy among geneticists is how polite to be about this study,” said Montgomery Slatkin, a mathematician at the University of California, Berkeley. Slatkin has written papers tracing the genetic history of sphingolipid disorders, a cluster of four common diseases. “I don’t know anyone who thinks it’s true.”
Cochran, the lead study author, is an independent researcher who was trained as a physicist and moved into population genetics late in life. He has not been afraid to dive into controversial material, and he has argued with mathematical modeling that homosexuality can be attributed to a viral infection.
The new work in Journal of Biosocial Science, published by Cambridge University Press, is a dizzying mix of history, science and anthropology. Many say it is the first effort in decades to look for a possible genetic answer for Jewish intelligence.
Cochran and his co-authors based their work on two established pillars of previous research. The first is the repeated studies that have shown Ashkenazic Jews to have a higher average IQ score than that of the American population at large. The Utah authors also point out that 27% of American Nobel Prize winners are Jewish.
The second pillar of the Utah study is the previous research that shows sphingolipid diseases to be prevalent among Ashkenazic Jews.
Researchers have long argued over why these diseases are prevalent among Ashkenazic Jews when they would have seemed to make carriers of the disease less likely to reproduce. The authors of the new study take their bold step by arguing that the diseases were passed on because they were the side effect of a genetic mutation that also caused greater intelligence. The side effect, they argue, was a small price to pay for the greater intelligence necessary for the professions that Jews occupied in Europe throughout the Middle Ages, such as money lending and trading (a small debate has already sprung up on the Internet about the historical prevalence of these professions among Ashkenazic Jews).
The Utah authors argue that the chemical process causing sphingolipid diseases also effects greater neurological development.
The work of Cochran’s team has been criticized on a number of levels, but at the most basic, Cochran’s critics say his study provides only statistical speculation, not physical proof of a link between the sphingolipid diseases and higher intelligence — and the study team makes no attempt to find the genetic location of the genes responsible for heightened intelligence.
“There’s no original data in this,” said Harry Ostrer, director of the human genetics program at New York University. “From that point of view, I would argue this is bad science. Bad science is what got eugenics into trouble in the past.”
Cochran acknowledges that his team’s work is a product of historical and statistical modeling, but he said that its goal from the beginning was to find a plausible hypothesis for other scientists to fully test.
“This is a hypothesis — we’re throwing it out to see if someone tests it,” Cochran said. “If I’m wrong, I’m wrong. If I’m right, I’m right.”
The swift response to the new work was to be expected. In recent years, suggestions that the intelligence levels of large groups can be explained by biological differences have come under steady fire. Earlier this year, Harvard’s president, Lawrence Summers, almost lost his job after suggesting that innate differences between women and men might account for the small number of female science professors. A decade ago, a long and angry discussion was provoked by Charles Murray and Richard Hernnstein’s “The Bell Curve,” which argued that genetic differences are the root of lower IQ levels among African-Americans.
The debate over “The Bell Curve “brought up a number of issues that are playing out in the current give-and-take about Jewish intelligence. Many critics of “The Bell Curve” argued that IQ scores are a signal of socially learned test-taking ability and income rather than innate intelligence.
The Jewish community has a particularly fraught relationship with the idea of inherent biological characteristics. The idea of biological differences separating the races came about in the late 18th century, and it was at the same time that racial antisemitism began to supplant an antisemitism that focused on religious practice. In America, though, historians say it was at the beginning of the 20th century that Jews became a large enough group to become a part of the discussion on racial differences among Americans.
In the populist protest against immigration in the early 20th century, racial characterizations of Jews were used against them. The apogee of the discussion came in a government document in 1911, known as the Dillingham Commission Report, which fueled the argument that American racial stock was being diluted by “inferior races.” The report noted that “the ‘Jewish nose,’ and to a lesser degree other facial characteristics, are found well-nigh everywhere throughout the race, although the form of the head seems to have become quite the reverse of the Semitic type.”
There was some effort in the Jewish community to counter this racial categorization. The American Jewish Committee successfully lobbied against efforts to label Jews as a separate race during the 1910 census. Later, AJCommittee helped finance Jewish anthropologist Franz Boas, a Columbia professor who initiated research into the idea that the differences between social groups were primarily attributable to environment not to science. But until the Nazi era began, biological ideas of race were the dominant tool for discussing categories of people, and many Jewish intellectuals took part in this.
“Before the 1920s there wasn’t a way of describing what today we would call ethnicity,” said Eric L. Goldstein, an Emory University professor who authored an upcoming book on Jews and racial identity in America. “Jews couldn’t step outside the language of race any more than anyone else — they just tried to turn it around and use it in a positive sense.”
That all changed after World War II, though, when the idea of racial science became thoroughly discredited as a result of the Nazi regime, Goldstein said. Not coincidentally, after the war, Boas became one of the founding fathers of a new anthropology focusing on culturally learned differences between societies.
“That’s when you find Jews and others in the West far less willing to embrace these racial ideas,” said Hart, the Florida-based historian. “It’s not because there’s any new scientific evidence; it’s just not politically tenable anymore.”
Hart and Goldstein agree that since the war, scientific discussions of Jewish distinctiveness generally have been taboo. But the geneticists studying diseases prevalent among Jews — like the sphingolipid diseases — have actually been treading on the ground of innate Jewish difference for years. These genetic researchers say they have often sensed reluctance in the community they are discussing.
“Any implication that Jews are different than other people causes a backlash,” said Ostrer, NYU’s human genetics program director. “It creates a typology for Jews which many have objected to.”
But moving from the realm of diseases to the realm of intellect is a large step that no researcher has been willing to take, until now. Ostrer said it’s a topic that could bear some fruit, but not with the methodology used by the Utah team.
For his part, Cochran said he hopes that someone takes up his team’s challenge to test his hypothesis. To begin, he proposes a study looking at whether people with Gaucher disease have higher IQ scores than siblings without the disease. But even once the findings come in, he is not sure they could make a dent in conventional wisdom.
“I predict that if we turn out to be right,” Cochran said, “we’d change the minds of maybe 100 people worldwide.”