Friday, December 21, 2007

Jewish Genius

Jewish Genius
Charles Murray

April 2007

"Jewish Genius"

Since its first issue in 1945, COMMENTARY has published hundreds of
articles about Jews and Judaism. As one would expect, they cover just
about every important aspect of the topic. But there is a lacuna, and
not one involving some obscure bit of Judaica. COMMENTARY has never
published a systematic discussion of one of the most obvious topics of
all: the extravagant overrepresentation of Jews, relative to their
numbers, in the top ranks of the arts, sciences, law, medicine,
finance, entrepreneurship, and the media.

I have personal experience with the reluctance of Jews to talk about
Jewish accomplishment—my co-author, the late Richard Herrnstein,
gently resisted the paragraphs on Jewish IQ that I insisted on putting
in The Bell Curve (1994). Both history and the contemporary revival of
anti-Semitism in Europe make it easy to understand the reasons for
that reluctance. But Jewish accomplishment constitutes a fascinating
and important story. Recent scholarship is expanding our understanding
of its origins.

And so this Scots-Irish Gentile from Iowa hereby undertakes to tell
the story. I cover three topics: the timing and nature of Jewish
accomplishment, focusing on the arts and sciences; elevated Jewish IQ
as an explanation for that accomplishment; and current theories about
how the Jews acquired their elevated IQ.


From 800 B.C.E. through the first millennium of the Common Era, we
have just two examples of great Jewish accomplishment, and neither
falls strictly within the realms of the arts or sciences. But what a
pair they are. The first is the fully realized conceptualization of
monotheism, expressed through one of the literary treasures of the
world, the Hebrew Bible. It not only laid the foundation for three
great religions but, as Thomas Cahill describes in The Gifts of the
Jews (1998), introduced a way of looking at the meaning of human life
and the nature of history that defines core elements of the modern
sensibility. The second achievement is not often treated as a Jewish
one but clearly is: Christian theology expressed through the New
Testament, an accomplishment that has spilled into every aspect of
Western civilization.

But religious literature is the exception. The Jews do not appear in
the annals of philosophy, drama, visual art, mathematics, or the
natural sciences during the eighteen centuries from the time of Homer
through the first millennium C.E., when so much was happening in
Greece, China, and South Asia. It is unclear to what extent this
reflects a lack of activity or the lack of a readily available record.
For example, only a handful of the scientists of the Middle Ages are
mentioned in most histories of science, and none was a Jew. But when
George Sarton put a high-powered lens to the Middle Ages in his
monumental Introduction to the History of Science (1927-48), he found
that 95 of the 626 known scientists working everywhere in the world
from 1150 to 1300 were Jews—15 percent of the total, far out of
proportion to the Jewish population.

As it happens, that same period overlaps with the life of the most
famous Jewish philosopher of medieval times, Maimonides (1135–1204),
and of others less well known, not to mention the Jewish poets,
grammarians, religious thinkers, scholars, physicians, and courtiers
of Spain in the "Golden Age," or the brilliant exegetes and rabbinical
legislators of northern France and Germany. But this only exemplifies
the difficulty of assessing Jewish intellectual activity in that
period. Aside from Maimonides and a few others, these thinkers and
artists did not perceptibly influence history or culture outside the
confines of the Jewish world.

Generally speaking, this remained the case well into the Renaissance
and beyond. When writing a book called Human Accomplishment (2003), I
compiled inventories of "significant figures" in the arts and
sciences, defined as people who are mentioned in at least half of the
major histories of their respective fields. From 1200 to 1800, only
seven Jews are among those significant figures, and only two were
important enough to have names that are still widely recognized:
Spinoza and Montaigne (whose mother was Jewish).


The sparse representation of Jews during the flowering of the European
arts and sciences is not hard to explain. They were systematically
excluded, both by legal restrictions on the occupations they could
enter and by savage social discrimination. Then came legal
emancipation, beginning in the late 1700's in a few countries and
completed in Western Europe by the 1870's, and with it one of the most
extraordinary stories of any ethnic group at any point in human history.

As soon as Jewish children born under legal emancipation had time to
grow to adulthood, they started appearing in the first ranks of the
arts and sciences. During the four decades from 1830 to 1870, when the
first Jews to live under emancipation reached their forties, 16
significant Jewish figures appear. In the next four decades, from 1870
to 1910, the number jumps to 40. During the next four decades,
1910–1950, despite the contemporaneous devastation of European Jewry,
the number of significant figures almost triples, to 114.

To get a sense of the density of accomplishment these numbers
represent, I will focus on 1870 onward, after legal emancipation had
been achieved throughout Central and Western Europe. How does the
actual number of significant figures compare to what would be expected
given the Jewish proportion of the European and North American
population? From 1870 to 1950, Jewish representation in literature was
four times the number one would expect. In music, five times. In the
visual arts, five times. In biology, eight times. In chemistry, six
times. In physics, nine times. In mathematics, twelve times. In
philosophy, fourteen times.

Disproportionate Jewish accomplishment in the arts and sciences
continues to this day. My inventories end with 1950, but many other
measures are available, of which the best known is the Nobel Prize. In
the first half of the 20th century, despite pervasive and continuing
social discrimination against Jews throughout the Western world,
despite the retraction of legal rights, and despite the Holocaust,
Jews won 14 percent of Nobel Prizes in literature, chemistry, physics,
and medicine/physiology. In the second half of the 20th century, when
Nobel Prizes began to be awarded to people from all over the world,
that figure rose to 29 percent. So far, in the 21st century, it has
been 32 percent. Jews constitute about two-tenths of one percent of
the world's population. You do the math.


What accounts for this remarkable record? A full answer must call on
many characteristics of Jewish culture, but intelligence has to be at
the center of the answer. Jews have been found to have an unusually
high mean intelligence as measured by IQ tests since the first Jewish
samples were tested. (The widely repeated story that Jewish immigrants
to this country in the early 20th century tested low on IQ is a
canard.) Exactly how high has been difficult to pin down, because
Jewish sub-samples in the available surveys are seldom perfectly
representative. But it is currently accepted that the mean is
somewhere in the range of 107 to 115, with 110 being a plausible

The IQ mean for the American population is "normed" to be 100, with a
standard deviation of 15. If the Jewish mean is 110, then the
mathematics of the normal distribution says that the average Jew is at
the 75th percentile. Underlying that mean in overall IQ is a
consistent pattern on IQ subtests: Jews are only about average on the
subtests measuring visuo-spatial skills, but extremely high on
subtests that measure verbal and reasoning skills.

A group's mean intelligence is important in explaining outcomes such
as mean educational attainment or mean income. The key indicator for
predicting exceptional accomplishment (like winning a Nobel Prize) is
the incidence of exceptional intelligence. Consider an IQ score of 140
or higher, denoting the level of intelligence that can permit people
to excel in fields like theoretical physics and pure mathematics. If
the mean Jewish IQ is 110 and the standard deviation is 15, then the
proportion of Jews with IQ's of 140 or higher is somewhere around six
times the proportion of everyone else.

The imbalance continues to increase for still higher IQ's. New York
City's public-school system used to administer a pencil-and-paper IQ
test to its entire school population. In 1954, a psychologist used
those test results to identify all 28 children in the New York
public-school system with measured IQ's of 170 or higher. Of those 28,
24 were Jews.

Exceptional intelligence is not enough to explain exceptional
accomplishment. Qualities such as imagination, ambition, perseverance,
and curiosity are decisive in separating the merely smart from the
highly productive. The role of intelligence is nicely expressed in an
analogy suggested to me years ago by the sociologist Steven Goldberg:
intelligence plays the same role in an intellectually demanding task
that weight plays in the performance of NFL offensive tackles. The
heaviest offensive tackle is not necessarily the best. Indeed, the
correlation between weight and performance among NFL offensive tackles
is probably quite low. But they all weigh more than 300 pounds.

So with intelligence. The other things count, but you must be very
smart to have even a chance of achieving great work. A randomly
selected Jew has a higher probability of possessing that level of
intelligence than a randomly selected member of any other ethnic or
national group, by far.


Nothing that I have presented up to this point is scientifically
controversial. The profile of disproportionately high Jewish
accomplishment in the arts and sciences since the 18th century, the
reality of elevated Jewish IQ, and the connection between the two are
not to be denied by means of data. And so we come to the great
question: how and when did this elevated Jewish IQ come about? Here,
the discussion must become speculative. Geneticists and historians are
still assembling the pieces of the explanation, and there is much room
for disagreement.

I begin with the assumption that elevated Jewish intelligence is
grounded in genetics. It is no longer seriously disputed that
intelligence in Homo sapiens is substantially heritable. In the last
two decades, it has also been established that obvious environmental
factors such as high income, books in the house, and parental reading
to children are not as potent as one might expect. A "good enough"
environment is important for the nurture of intellectual potential,
but the requirements for "good enough" are not high. Even the very
best home environments add only a few points, if that, to a merely
okay environment. It is also known that children adopted at birth do
not achieve the IQ's predicted by their parents' IQ.

To put it another way, we have good reason to think that Gentile
children raised in Jewish families do not acquire Jewish intelligence.
Hence my view that something in the genes explains elevated Jewish IQ.
That conclusion is not logically necessary but, given what we know
about heritability and environmental effects on intelligence in humans
as a species, it is extremely plausible.

Two potential explanations for a Jewish gene pool favoring high
intelligence are so obvious that many people assume they must be true:
winnowing by persecution (only the smartest Jews either survived or
remained Jews) and marrying for brains (scholars and children of
scholars were socially desirable spouses). I too think that both of
these must have played some role, but how much of a role is open to

In the case of winnowing through persecution, the logic cuts both
ways. Yes, those who remained faithful during the many persecutions of
the Jews were self-selected for commitment to Judaism, and the role of
scholarship in that commitment probably means that intelligence was
one of the factors in self-selection. The foresight that goes with
intelligence might also have had some survival value (as in
anticipating pogroms), though it is not obvious that its effect would
be large enough to explain much.

But once the Cossacks are sweeping through town, the kind of
intelligence that leads to business success or rabbinical acumen is no
help at all. On the contrary, the most successful people could easily
have become the most likely to be killed, by virtue of being more
visible and the targets of greater envy. Furthermore, other groups,
such as the Gypsies, have been persecuted for centuries without
developing elevated intelligence. Considered closely, the
winnowing-by-persecution logic is not as compelling as it may first

What of the marrying-for-brains theory? "A man should sell all he
possesses in order to marry the daughter of a scholar, as well as to
marry his daughter to a scholar," advises the Talmud (Pesahim 49a),
and scholarship did in fact have social cachet within many Jewish
communities before (and after) emancipation. The combination could
have been potent: by marrying the children of scholars to the children
of successful merchants, Jews were in effect joining those selected
for abstract reasoning ability with those selected for practical

Once again, however, it is difficult to be more specific about how
much effect this might have had. Arguments have been advanced that
rich merchants were in fact often reluctant to entrust their daughters
to penniless and unworldly scholars. Nor is it clear that the
fertility rate of scholars, or their numbers, were high enough to
account for a major effect on intelligence. The attractiveness of
brains in prospective marriage partners surely played some role but,
once again, the data for assessing how much have not been assembled.


Against this backdrop of uncertainty, a data-driven theory for
explaining elevated Jewish IQ appeared in 2006 in the Journal of
Biosocial Science. In an article entitled "Natural History of
Ashkenazi Intelligence," Gregory Cochran (a physicist) and Jason Hardy
and Henry Harpending (anthropologists) contend that elevated Jewish IQ
is confined to the Ashkenazi Jews of northern and central Europe, and
developed from the Middle Ages onward, primarily from 800 to 1600 C.E.

In the analysis of these authors, the key factor explaining elevated
Jewish intelligence is occupational selection. From the time Jews
became established north of the Pyrenees-Balkans line, around 800
C.E., they were in most places and at most times restricted to
occupations involving sales, finance, and trade. Economic success in
all of these occupations is far more highly selected for intelligence
than success in the chief occupation of non-Jews: namely, farming.
Economic success is in turn related to reproductive success, because
higher income means lower infant mortality, better nutrition, and,
more generally, reproductive "fitness." Over time, increased fitness
among the successful leads to strong selection for the cognitive and
psychological traits that produce that fitness, intensified when there
is a low inward gene flow from other populations—as was the case with

Sephardi and Oriental Jews—i.e., those from the Iberian peninsula, the
Mediterranean littoral, and the Islamic East—were also engaged in
urban occupations during the same centuries. But the authors cite
evidence that, as a rule, they were less concentrated in occupations
that selected for IQ and instead more commonly worked in craft trades.
Thus, elevated intelligence did not develop among Sephardi and
Oriental Jews—as manifested by contemporary test results in Israel
that show the IQ's of non-European Jews to be roughly similar to the
IQ's of Gentiles.

The three authors conclude this part of their argument with an elegant
corollary that matches the known test profiles of today's Ashkenazim
with the historical experience of their ancestors:

The suggested selective process explains the pattern of mental
abilities in Ashkenazi Jews: high verbal and mathematical ability but
relatively low spatio-visual ability. Verbal and mathematical talent
helped medieval businessmen succeed, while spatio-visual abilities
were irrelevant.

The rest of their presentation is a lengthy and technical discussion
of the genetics of selection for IQ, indirect evidence linking
elevated Jewish IQ with a variety of genetically based diseases found
among Ashkenazim, and evidence that most of these selection effects
have occurred within the last 1,200 years.


No one has yet presented an alternative to the
Cochran-Hardy-Harpending theory that can match it for documentation.
But, as someone who suspects that elevated Jewish intelligence was (a)
not confined to Ashkenazim and (b) antedates the Middle Ages, I will
outline the strands of an alternative explanation that should be explored.

It begins with evidence that Jews who remained in the Islamic world
exhibited unusually high levels of accomplishment as of the beginning
of the second millennium. The hardest evidence is Sarton's enumeration
of scientists mentioned earlier, of whom 15 percent were Jews. These
were not Ashkenazim in northern Europe, where Jews were still largely
excluded from the world of scientific scholarship, but Sephardim in
the Iberian peninsula, in Baghdad, and in other Islamic centers of
learning. I have also mentioned the more diffuse cultural evidence
from Spain, where, under both Muslim and Christian rule, Jews attained
eminent positions in the professions, commerce, and government as well
as in elite literary and intellectual circles.

After being expelled from Spain at the end of the 15th century,
Sephardi Jews rose to distinction in many of the countries where they
settled. Some economic historians have traced the decline of Spain
after 1500, and the subsequent rise of the Netherlands, in part to the
Sephardi commercial talent that was transferred from the one to the
other. Centuries later, in England, one could point to such Sephardi
eminences as Benjamin Disraeli and the economist David Ricardo.

In sum, I propose that a strong case could be assembled that Jews
everywhere had unusually high intellectual resources that manifested
themselves outside of Ashkenaz and well before the period when
non-rabbinic Ashkenazi accomplishment manifested itself.

How is this case to be sustained in the face of contemporary test data
indicating that non-Ashkenazi Jews do not have the elevated mean of
today's Ashkenazim? The logical inconsistency disappears if one posits
that Jews circa 1000 C.E. had elevated intelligence everywhere, but
that it subsequently was augmented still further among Ashkenazim and
declined for Jews living in the Islamic world—perhaps because of the
dynamics described by Cochran, Hardy, and Harpending (that is,
Oriental Jews were concentrated in trades for which high intelligence
did not yield wealth).

Recent advances in the use of genetic markers to characterize
populations enable us to pursue such possibilities systematically. I
offer this testable hypothesis as just one of many possibilities: if
genetic markers are used to discriminate among non- Ashkenazi Jews, it
will be found that those who are closest genetically to the Sephardim
of Golden Age Spain have an elevated mean IQ, though perhaps not so
high as the contemporary Ashkenazi IQ.


The next strand of an alternative to the Cochran-Hardy-Harpending
theory involves reasons for thinking that some of the elevation of
Jewish intelligence occurred even before Jews moved into occupations
selected for intelligence, because of the shift in ancient Judaism
from a rite-based to a learning-based religion.

All scholars who have examined the topic agree that about 80–90
percent of all Jews were farmers at the beginning of the Common Era,
and that only about 10–20 percent of Jews were farmers by the end of
the first millennium. No other ethnic group underwent this same kind
of occupational shift. For the story of why this happened, I turn to a
discussion by Maristella Botticini and Zvi Eckstein entitled "Jewish
Occupational Selection: Education, Restrictions, or Minorities?" which
appeared in the Journal of Economic History in 2005.

Rejecting the explanation that Jews became merchants because they were
restricted from farming, Botticini and Eckstein point to cases in
which Jews who were free to own land and engage in agriculture made
the same shift to urban, skilled occupations that Jews exhibited where
restrictions were in force. Instead, they focus on an event that
occurred in 64 C.E., when the Palestinian sage Joshua ben Gamla issued
an ordinance mandating universal schooling for all males starting at
about age six. The ordinance was not only issued; it was implemented.
Within about a century, the Jews, uniquely among the peoples of the
world, had effectively established universal male literacy and numeracy.

The authors' explanation for the subsequent shift from farming to
urban occupations reduces to this: if you were educated, you possessed
an asset that had economic value in occupations that required literacy
and numeracy, such as those involving sales and transactions. If you
remained a farmer, your education had little or no value. Over the
centuries, this basic economic reality led Jews to leave farming and
engage in urban occupations.

So far, Botticini and Eckstein have provided an explanatory backdrop
to the shift in occupations that in turn produced the selection
pressures for intelligence described by Cochran, Hardy, and
Harpending. But selection pressure in this classic form was probably
not the only force at work. Between the 1st and 6th centuries C.E.,
the number of Jews in the world plummeted from about 4.5 million to
1.5 million or fewer. About 1 million Jews were killed in the revolts
against the Romans in Judea and Egypt. There were scattered forced
conversions from Judaism to another religion. Some of the reduction
may be associated with a general drop in population that accompanied
the decline and fall of the Roman Empire. But that still leaves a huge
number of Jews who just disappeared.

What happened to them? Botticini and Eckstein argue that an economic
force was at work: for Jews who remained farmers, universal education
involved a cost that had little economic benefit. As time went on,
they drifted away from Judaism. I am sure this explanation has some
merit. But a more direct explanation could involve the increased
intellectual demands of Judaism.

Joshua ben Gamla's ordinance mandating literacy occurred at about the
same time as the destruction of the Second Temple—64 C.E. and 70 C.E.,
respectively. Both mark the moment when Judaism began actively to
transform itself from a religion centered on rites and sacrifices at
the Temple in Jerusalem to a religion centered on prayer and the study
of the Torah at decentralized synagogues and study houses. Rabbis and
scholars took on a much larger role as leaders of local communities.
Since worship of God involved not only prayer but study, all Jewish
males had to read if they were to practice their faith—and not only
read in private but be able to read aloud in the presence of others.

In this context, consider the intellectual requirements of literacy.
People with modest intelligence can become functionally literate, but
they are able to read only simple texts. The Torah and the Hebrew
prayer book are not simple texts; even to be able to read them
mechanically requires fairly advanced literacy. To study the Talmud
and its commentaries with any understanding requires considerable
intellectual capacity. In short, during the centuries after Rome's
destruction of the Temple, Judaism evolved in such a way that to be a
good Jew meant that a man had to be smart.

What happened to the millions of Jews who disappeared? It is not
necessary to maintain that Jews of low intelligence were run out of
town because they could not read the Torah and commentaries fluently.
Rather, few people enjoy being in a position where their inadequacies
are constantly highlighted. It is human nature to withdraw from such
situations. I suggest that the Jews who fell away from Judaism from
the 1st to 6th centuries C.E. were heavily concentrated among those
who could not learn to read well enough to be good Jews—meaning those
from the lower half of the intelligence distribution. Even before the
selection pressures arising from urban occupations began to have an
effect, I am arguing, the remaining self-identified Jews circa 800
C.E. already had elevated intelligence.


A loose end remains. Is it the case that, before the 1st century C.E.,
Jews were intellectually ordinary? Are we to believe that the Bible, a
work compiled over centuries and incorporating everything from
brilliant poetry to profound ethics, with stories that speak so
eloquently to the human condition that they have inspired great art,
music, and literature for millennia, was produced by an intellectually
run-of-the-mill Levantine tribe?

In The Evolution of Man and Society (1969), the geneticist Cyril
Darlington presented the thesis that Jews and Judaism were decisively
shaped much earlier than the 1st century C.E., namely, by the
Babylonian captivity that began with the fall of Jerusalem to the
forces of Nebuchadnezzar in 586 B.C.E.

Darlington's analysis touches on many issues, but I will focus on just
the intelligence question. The biblical account clearly states that
only a select group of Jews were taken to Babylon. We read that
Nebuchadnezzar "carried into exile all Jerusalem: all the officers and
fighting men, and all the craftsmen and artisans. . . . Only the
poorest people of the land were left" (2 Kings 24:10).

In effect, the Babylonians took away the Jewish elites, selected in
part for high intelligence, and left behind the poor and unskilled,
selected in part for low intelligence. By the time the exiles
returned, more than a century later, many of those remaining behind in
Judah had been absorbed into other religions. Following Ezra's command
to "separate yourselves from the peoples around you and from your
foreign wives" (Ezra 10:9), only those who renounced their foreign
wives and children were permitted to stay within the group. The
returned exiles, who formed the bulk of the reconstituted Jewish
community, comprised mainly the descendants of the Jewish
elites—plausibly a far more able population, on average, than the
pre-captivity population.

I offer the Babylonian captivity as a concrete mechanism whereby
Jewish intelligence may have been elevated very early, but I am not
wedded to it. Even without that mechanism, there is reason to think
that selection for intelligence antedates the 1st century C.E.

From its very outset, apparently going back to the time of Moses,
Judaism was intertwined with intellectual complexity. Jews were
commanded by God to heed the law, which meant they had to learn the
law. The law was so extensive and complicated that this process of
learning and reviewing was never complete. Moreover, Jewish males were
not free to pretend that they had learned the law, for fathers were
commanded to teach the law to their children. It became obvious to all
when fathers failed in their duty. No other religion made so many
intellectual demands upon the whole body of its believers. Long before
Joshua ben Gamla and the destruction of the Second Temple, the
requirements for being a good Jew had provided incentives for the less
intelligent to fall away.

Assessing the events of the 1st century C.E. thus poses a
chicken-and-egg problem. By way of an analogy, consider written
Chinese with its thousands of unique characters. On cognitive tests,
today's Chinese do especially well on visuo-spatial skills. It is
possible, I suppose, that their high visuo-spatial skills have been
fostered by having to learn written Chinese; but I find it much more
plausible that only people who already possessed high visuo-spatial
skills would ever devise such a ferociously difficult written
language. Similarly, I suppose it is possible that the Jews' high
verbal skills were fostered, through secondary and tertiary effects,
by the requirement that they be able to read and understand
complicated texts after the 1st century C.E.; but I find it much more
plausible that only people who already possessed high verbal skills
would dream of installing such a demanding requirement.

This reasoning pushes me even farther into the realm of speculation.
Insofar as I am suggesting that the Jews may have had some degree of
unusual verbal skills going back to the time of Moses, I am naked
before the evolutionary psychologists' ultimate challenge. Why should
one particular tribe at the time of Moses, living in the same
environment as other nomadic and agricultural peoples of the Middle
East, have already evolved elevated intelligence when the others did not?

At this point, I take sanctuary in my remaining hypothesis, uniquely
parsimonious and happily irrefutable. The Jews are God's chosen people.

No comments: