The Intelligence of American Jews
Dr. Richard Lynn
The Intelligence of American Jews
Sat Feb 14 01:24:26 2004
64.140.158.107

The Intelligence of American Jews
Dr. Richard Lynn
University of Ulster, Coleraine, Northern Ireland
http://www.rlynn.co.uk

Summary. This paper provides new data on the theory that Jews have a higher
average level of verbal intelligence than non-Jewish whites. The theory is
considered by examining the vocabulary scores of Jews, non-Jewish whites, blacks
and others obtained in the American General Social Surveys carried out by the
National Opinion Research Centre in the years 1990-1996. Vocabulary size is a
good measure of verbal intelligence. Jews obtained a significantly higher mean
vocabulary score than non-Jewish whites, equivalent to an IQ advantage of 7.5
IQ points. The results confirm previous reports that the verbal IQ of American
Jews is higher than that of non-Jewish whites.

Key words: Jews, intelligence

Introduction

It has often been asserted that Jews have a higher average level of
intelligence than non-Jewish whites of European origin. Herrnstein and Murray (1994,
p.275) have written that "Whenever the subject of group differences comes up one
of the questions sure to be asked is 'Are Jews really smarter than everyone
else?' ” and their answer to this question is an affirmative. Eysenck
(1995,p.159) asserted that "As far as Jews are concerned, there is no question that
they score very highly on IQ tests". Levin (1997,p.132) has written that “in
every society in which they have participated, Jews have eventually been
recognised (and disliked for) their exceptional talent”. Seligman (1992, p.133) writes
of "the extraordinarily high Jewish g levels”.

Despite these assertions, the purported high IQ of the Jews has never been
systematically reviewed and is not even mentioned in recent textbooks on
intelligence, such as those of Brody (1992) and Mackintosh (1998).

There have nevertheless been a number of studies of the intelligence of Jews
in the United States. Among those who have discussed this question, there is a
general consensus on two points. First, that Jews have a higher average IQ
than gentile whites (this term is used for non-Jewish whites). Second, that Jews
are stronger on verbal ability than on visualization and visual-spatial
ability. Beyond this, there is a considerable range of conclusions. A review by
MacDonald (1994,p.190) concludes that “taken together, the data suggest a mean IQ
in the 117 range for Ashkenazi Jewish children, with a verbal IQ in the range
of 125 and a performance IQ in the average range”. Storfer (1990,p.314)
writes that “Jewish people, considered as a group, tend to excel in some cognitive
domains – for example, verbal and numerical ability – but not in others, as
witness their unexceptional performance on certain types of spatial or
perceptual problems. Storfer concludes that American Jews have an average IQ of about
112 on the Stanford-Binet, largely a test of verbal ability.

Herrnstein and Murray (1994, p.275) reach a similar conclusion “A fair
estimate seems to be that Jews in America and Britain have an overall IQ mean
somewhere between a half and a full standard deviation above the mean, with the
source of the difference concentrated in the verbal component” (1994, p.275). In
the sample they analysed, Jews had an average IQ of 112.6 in relation to
American whites on four verbal subtests (word knowledge, paragraph comprehension,
arithmetic and mathematics) of the AFQT (Armed Forces Qualification Test). Their
estimate of a Jewish advantage of between a half and a full standard
deviation is equivalent to an IQ range of 7.5 to 15 IQ points. The estimates proposed
by Storfer and Herrnstein and Murray are similar but much lower than that
suggested by MacDonald (1994).

Despite the widespread consensus on the high Jewish verbal ability, not all
studies have shown that Jews have a higher verbal IQ than gentiles.
Furthermore, virtually all the existing studies are unsatisfactory because the samples
have been unrepresentative, very small or for other reasons. An early study
carried out in the mid-1920s of 702 Jewish and 1030 non-Jewish white 9-13 year
olds tested with the Pintner-Cunningham test (a largely verbal test) by Hirsch
(1926) found the Jewish children obtained a mean IQ only 1.5 IQ points higher
than the gentiles. However, at this time a number of Jewish families spoke
Yiddish as their first language and this would have handicapped the children to an
unknown extent. A later study by Shuey (1942) of students entering Washington
Square College in New York in 1935-7 tested with the American Council
Psychological Examination, a test of verbal abilities (with subtests of completion,
arithmetic, artificial language, analogies and opposites) found that 764 Jewish
freshmen scored 1.2 IQ points below 236 non-Jewish whites. All the students
were native born, possibly suggesting that the performance of the Jewish
students was unlikely to have been depressed by unfamiliarity with the English
language although some of these may still have been speaking Yiddish as their first
language.

Furthermore, Jewish and gentile students at this college cannot be regarded
as respresentative of their respective communities. A more recent study by
Hennessy and Merrifield (1978) with an impressive sample size of 2,985 Jewish,
gentile, black and Hispanic college bound high school seniors found a difference
of less than 1 IQ point between Jews and gentiles on tests of verbal ability
and reasoning but the sample may not have been representative of the
populations.

Another problem with a number of the studies that have found that Jews have
higher verbal IQs than gentiles is that several of them are based on very small
sample sizes. For instance, Seligman (1990, p.130) writes that “Jewish verbal
superiority appears unmatched in any other ethnic group. An often-quoted 1970
study performed by the Ann Arbor Institute for Social Research shows Jewish
tenth-grade boys with an average verbal IQ equivalent of 112.8 (on the
Stanford-Binet metric) about three quarters of a standard deviation above the average
for non-Jewish white boys”. This is the Bachman (1970) study in which the
number of Jewish boys was 65. In the Herrnstein and Murray (1994) data set in
which Jews obtained a mean verbal IQ of 112.6, the sample size was 98 and was not
drawn to be nationally representative. There is only one study of the
intelligence of American Jews in the last half century which appears to be
representative and had a reasonable sample size. This is Backman’s (1972) analysis of the
data in Project Talent, a nationwide American survey of the abilities of 18
year olds carried out in 1960. The study had sample sizes of 1,236 Jews and
1,051 white gentiles (in addition to 488 blacks and 150 Orientals). IQs for six
factors were calculated. The mean IQs of the Jews in relation to gentile white
means of 100 and standard deviations of 15 were as follows: verbal knowledge
(described as “a general factor, but primarily a measure of general
information” and identifiable with Carroll’s (1993) gc or verbal comprehension factor -
107.8; English language – 99.5; mathematics – 109.7; visual reasoning (“a
measure of reasoning with visual forms”) – 91.3; perceptual speed and accuracy –
102.2; memory (short term recall of verbal symbols) – 95.1. These results are
consistent with the general consensus that Jews perform well on tests of
verbal ability (although not of English language) and mathematics and less well on
visual and spatial tests but the verbal IQ of 107.8 is towards the low end of
the estimates of Jewish verbal ability suggested by Herrnstein and Murray of
an IQ between 107.5 and 115. However, the differences in the IQs for the
various abilities are so great as to raise doubts about the results.

The existing state of the research literature on the IQ of American Jews is
therefore that some studies have shown that their verbal IQ is about the same
as that of gentile whites while other studies have shown that it is
considerably higher at 107.8 (Backman, 1972), 112.6 (Herrnstein and Murray, 1994) and
112.8 (Bachman, 1970). However, the last of two of these studies have sample
sizes of fewer than 100. There is room for more data on the IQ of American Jews,
and it is to the presentation of this that we now turn.

Method

The American National Opinion Research Center (NORC) in Chicago carries out
annual surveys on approximately 1,500 individuals in continental United States
(ie. excluding Hawaii and Alaska). The samples are representative of the adult
population of those aged 18 years and over except that they exclude those who
cannot speak English and those resident in institutions such as prisons and
hospitals. Full details of the sampling procedures are given by Davis and Smith
(1996).

The NORC surveys collect a vast amount of information about the respondents'
opinions on a variety of topics and also on their demographic characteristics
such as their income, education, age, ethnic group, religion, etc.etc. The
first items of information of particular interest to us are the respondents'
religion and ethnic group. An analysis of these enables us to categorise the
respondents as Jewish, non-Jewish white, black and other. The second item of
interest is the respondents' score on a 10 word vocabulary test. Vocabulary is a
good measure of both general intelligence and verbal intelligence. For instance,
in the standardisation sample of the Wechsler Adult Intelligence Scale (WAIS)
the vocabulary subtest correlates .75 with the Full Scale IQ, more highly than
any other subtest (Wechsler,1958) and the Full Scale IQ is widely regarded as
a good measure of general intelligence or Spearman’s g (Jensen, 1998). We are
therefore able to examine the vocabulary scores as a measure of the verbal
and general intelligence of the four religious/ethnic groups.

As noted, the annual NORC surveys are carried out on approximately 1,500
individuals. A single year does not therefore provide many Jews. To rectify this
problem we can take the results of a number of years and combine them. This
gives rise to a further problem that the vocabulary test has not been
administered in every annual survey. From 1990 onwards, the vocabulary test was given in
1990, 1991, 1992, 1994 and 1996. The data collected in these years are used to
analyse the vocabulary scores of the four ethnic/racial groups.

Results

The results are shown in Table 1. Reading from left to right, the columns
show the numbers in the four groups, the mean vocabulary scores, standard
deviations and conventional IQs based on a gentile white mean of 100 and standard
deviation of 15. Thus, expressed in this way, the Jewish group obtains a mean IQ
of 107.5, significantly higher than the gentile whites (t=5.82); the blacks
obtain a mean IQ of 89.7, significantly lower than that of gentile whites
(t=17.89); the “others” obtain a mean IQ of 98.6, not significantly different from
that of gentile whites.

Table 1. Vocabulary scores and verbal IQs of American Jews, non-Jewish
whites, blacks and others.

Ethnic Group N Mean Sd IQ
Jews 150 7.32 2.16 107.5
Gentiles 5300 6.28 2.03 100.0
Blacks 806 4.96 1.94 89.7
Others 219 6.09 2.37 98.6

Discussion

The results provide seven points of interest. First, they confirm the
previous studies showing that American Jews have a higher average verbal intelligence
level than non-Jewish whites. Second, the 7.5 IQ point Jewish advantage is
rather less than that generally proposed and found in the studies reviewed in
the introduction finding that Jews have verbal IQs in the range of 110-113 but
is closely similar to the figure of 107.8 obtained in the Bachman study which
is arguably the most satisfactory of the previous studies in terms of the size
and representativeness of the sample.

Third, the present data has strengths in comparison with a number of previous
studies in so far as they are based on a nationally representative and
reasonably large sample size of 150 Jews and 5,300 gentile whites. The very close
similarity between the present result and the Bachman result suggests that the
best reading of the verbal IQ of American Jews is 107.5 (present study) or
107.8 (Bachman). These figures are well below previous estimates of Jewish verbal
ability.

Four, an average verbal IQ of 107.5 would confer a considerable advantage for
American Jews in obtaining success in professional work. There would be
approximately four times as many Jews with IQs above 130, compared with gentile
whites. This may provide a plausible explain for the 4.8 over-representation of
Jews listed in American reference books of the successful such as Who’s Who,
American Men and Women of Science, The Directory of Directors, The Directory of
Medical Specialists and the like and calculated by Weyl (1989).

Five, the small difference of 1.4 IQ points between the non-Jewish whites and
the “other” category is not statistically significant or very informative.
The category is largely made up of Hispanics and Asians, which are themselves a
heterogeneous category. Hispanics have mean IQs below whites (e.g. Herrnstein
and Murray,1994), East Asians have about the same IQ as whites (Flynn, 1992)
or slightly higher than whites (Lynn,1995), while South Asians have mean IQs
lower than those of whites according to the calculations of Flynn (1992).
Aggregating these groups produces a combined mean very close to that of non-Jewish
whites.

Six, despite some three quarters of a century of research and quite a number
of papers on the intelligence of American Jews there is still a lot of useful
research to be done on this question. Probably the best approach would be to
analyse Jewish abilities in terms of the construct of g and of the eight second
order cognitive factors in the taxonomy of intelligence proposed by Carroll
(1993) and the similar taxonomy advanced by McGrew and Flanagan (1998). These
second order factors are fluid intelligence (reasoning), crystallized
intelligence (verbal comprehension and knowledge), general memory and learning,
visualization, broad retrieval ability, cognitive speed and processing speed.
Probably all that can be concluded with a fair degree of confidence at present is
that Jews have high crystallized intelligence (verbal ability) of which the
vocabulary test used in the present study is a good measure and that on this
ability their IQ in relation to gentile whites is approximately 107.5. The Backman
(1972) provides IQs for several of the second order factors (given in the
introduction to this paper) but these are so variable and in some instances so low
as to raise doubts about their credibility. It is difficult to credit that the
Jewish sample could have a non-verbal reasoning IQ of 91.3, and at the same
time a mathematical IQ (“quantitative reasoning” in the McGrew and Flanagan
taxonomy) of 109.7. It is also difficult to credit that the Jewish sample could
have a verbal IQ of 107.8 while at the same time having a short term verbal
memory IQ of 95.1. These results are in need of checking and replication. At
present it is doubtful whether any conclusion can be reached about the
intelligence of American Jews except that their verbal intelligence or, if this is
preferred, their gc (crystallized intelligence) is about 107.5.

Seven, the factors responsible for the high Jewish verbal IQ raise
interesting questions. It has been proposed by MacDonald (1994) that these lie in
centuries of eugenic customs, especia

 


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