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Triglav
Wednesday, October 15th, 2003, 12:15 AM
http://www.uni-magdeburg.de/jaencke/paper/brainsize.pdf

RoundskullBoredguy
Friday, October 24th, 2003, 08:43 AM
Ha, so very true; brain size is no reliable indicator for intelligence. Of course, that's not to say you can get by with one the size of an egg. :P

Glenlivet
Wednesday, January 7th, 2004, 06:27 PM
Does Brain size matter? A Reply to Rushton and Ankney

by MICHAEL PETERS, University of Guelph


Rushton and Ankney (1995) suggest that I was in error when
rejecting the claim (Lynn, 1993) that a relation between brain size
and intelligence is firmly established. Since my note went to press
(Peters, 1993), several papers have appeared which indicate a sizeable
relation between brain size, as determined by mri scan, and IQ
(Andreasen, Flaum, Swayze, O'Leary, Alliger, Cohen, Ehrhardtm, &
Yuhet, 1993; Egan, Chiswick, Santosh, Naidu, Rimmington, & Bestet,
1994; Raz, Torres, Spencer, Millman, Baertschi, & Sarpel, 1993;
Wickett, Vernon, & Lee, 1994). Each of the above studies has some
problems posed by method and interpretations or by the findings
themselves. For example, Egan et al. found the highest correlation not
between brain matter and IQ, but between cerebrospinal fluid volume
and IQ (r = .8), an inexplicable result for those who argue that it is
brain matter which is correlated with IQ. Nevertheless, as a group,
these studies justify the conclusion that there is a positive and
sizable correlation between brain size and IQ. This lends credibility
to earlier claims by Willerman, Schultz, Rutledge, & Bigler, 1991;
1992) and supports Rushton & Ankney's critIQue. The new mri data are
important because studies that relate IQ to brain size as estimated
through cranial parameters remain contradictory. For example, Reed and
Jensen (1993) report an equivalent cranial capacity of 1550 cm3 for a
high IQ group (124-136) and 1549 cm3 for a low IQ group (87-111),
whereas studies listed by Wickett et al. (1994) report positive
correlations between cranial capacity and IQ.

Accepting the fact that MRI data document a significant correlation
between brain size and intelligence within demographically homogeneous
groups, the question of causality arises. Neural systems, by
definition, have evolved to interact with the environment, and the
very significant expansion of brain size after birth, driven by a
growth of synapses and cortical interconnections, is interactive with
environmental input (Bedi, Massey, & Smart, 1989; Jacobsen, 1991, pp.
266-270; Walsh, 1981). Thus, nutritional and environmental conditions
which foster good development of intelligence can be expected to
foster good physical brain development as well. My seemingly
nonsensical position, that under some conditions it is useful to
control for body size when looking at brain/IQ relations, is based on
the possibility that the relation between brain size and IQ is
confounded by nutritional and environmental conditions (cf.
Passingham, 1979; Rodriguez, Donnadien, Martinez, & Chavez, 1979).
This does not change the basic observations, but it does change
arguments about causation.

Sex, IQ and brain size

Rushton & Ankney reiterate the conclusion, already reached by Gould
(1981, p. 106), that women have absolutely much smaller, and
relatively somewhat smaller brains than men. I continue to disagree
with Rushton & Ankney on the issue of scaling. The statement that
allometric technIQues standard in comparative biology have been used
does not assure that these are appropriately used for between sex
comparisons. In the available brain size/IQ studies, the differences
in IQ are small or non-existent (Passingham, 1979; Raz et al., 1993;
Willerman et al., 1991), in spite of very large differences in brain
size. Three interpretations offer themselves: (a) women do have lower
IQ's than men after all (Lynn, 1994), (b) the gross brain size in
women is not a meaningful index for comparison because of difficulties
in scaling body/brain parameters across sexes and possible differences
in fine structure (Peters, 1991; Willerman et al., 1991), and (c)
women and men differ especially on specific spatial tasks (Rushton &
Ankney, 1995). Because most of the mri evidence is cast in terms of
standard IQ test/brain size relations, it is interesting to note that
the sex differences in Wechsler IQ which are summarized by Lynn are
very small relative to the sex differences in brain size. This
supports interpretation (b). Rushton & Ankney's point (c) is difficult
to evaluate at this point. Rushton & Ankney emphasize spatial ability,
and point out that there are significant sex differences in 3-d
spatial abilities, especially mental rotation performance. However,
Wickett et al. find no significant correlation between brain size and
mental rotation performance in their sample of women, and considerably
lower correlations between Wechsler performance IQ and brain size than
for Wechsler verbal IQ and brain size. Caution is advised in
attributing spatial performance to brain size or neuron counts because
such performance is very sensitive to practice; women can improve
their mental rotation performance by 30% to 50 % (Peters, Chisholm, &
Laeng, 1995) after only a single exposure to the test. Such rapid
improvement is difficult to reconcile with the idea that brain size,
within normal limits, is the limiting factor in 3-d spatial
performance.

Race and IQ differences

Rushton and Ankney (1995) classify races into three groups, and this
has been a source of contention (e.g., Weizmann et al., 1990). The
issue of race classification is a major problem in anthropology
(Harrison, Tanner, Pilbeam, & Baker, 1988; p. 326) and cannot be
addressed here. Rushton & Ankney have adopted an essentially
operational definition that shares the strengths and weaknesses of
such definitions. To simplify things, I shall adopt the terms
Caucasoid, Mongoloid, and Negroid when referring to the data in
Rushton's work.

Much of Rushton and Ankney's (1995) case on racial differences in
brain size is based on estimates derived from cranial measures. Such
estimates are not without problems (Hoadley & Pearson, 1929; Wickett
et al., 1994, Willerman et al., 1991), and may have different validity
for men and women. As an illustration, Willerman et al. (1992), found
a significant correlation between brain size and head perimeter for
women, but not for men. Nevertheless, let us assume that cranial
measures do provide an imperfect but acceptable estimate of brain
size. Rushton & Ankney encounter several problems in the attempt to
generalize the mri/brain size/IQ data to the general context of racial
comparisons. One of the problems lies in the simplified grouping of
races, because this tends to give insufficient weight to within- group
variations.

Rushton's (1991) own data illustrate the point. Within the Caucasoid
grouping, a 1969 sample of Iranian soldiers is given an average
estimated cranial capacity of 1356 cm3, whereas a 1966 sample of
American Army soldiers has an average of 1470 cm3. Similarly, a 1967
us Air Force sample has 1539 cm3, whereas a 1975 German Air Force
sample has 1455 cm3. Within the Mongoloid grouping, a 1963 sample of
Thai soldiers has an estimated average of 1340 cm3, whereas a 1965
sample of South Vietnamese has 1299 cm3. All of these differences are
much larger than the differences obtained between Negroid (1449 cm3),
Caucasoid (1468 cm3), and Mongol- oid (1464 cm3) enlisted men from a
1988 us Army cohort using Rushton's (1992) terms and data. There are
also secular changes within a culture and racial group (Haug, 1984;
Miller & Corsellis, 1977). For example, us Air Force personnel
measured in 1967 had estimated brain sizes that exceeded by 68 cm3
values from a us Air Force sample drawn in 1950 (Rushton, 1991). In
face of such variation within groupings, between cultures for similar
groupings, and between different cohorts drawn within a culture,
generally valid statements about race differences are difficult to
make.

Two additional points need to be made. Rushton and Ankney (1995)
suggest that cranial capacity estimates for Mongoloid-, Caucasoid-,
and Negroid-Americans are 1416, 1380, and 1359 cm3, respectively,
indicating larger differences than Rushton's (1992) values given above
for these groups (1464, 1468, 1449cm3). The former values for the
three groups represent cranial capacity estimates which are based on
values corrected for body parameters (Rushton, 1992). To perform this
correction, Rushton used slopes for the log/log plot of brain against
body weight which are not appropriate for within- species comparisons
(Harvey, 1988). For comparison of individuals drawn from the same
species, a slope which is almost horizontal is appropriate, and should
be close to the .08 determined empirically by Reed and Jensen (1993).
This is borne out by other available evidence. Wickett et al. (1994)
state that for their sample of white women, it would appear that the
size of the brain is largely independent of body size (p. 836).
Similarly, Jerison (1979) found no significant association between
body weight or height and brain weight for men within the age range of
29 to 41 years of age. A conservative conclusion is that there is no
legitimate reason for using steep slopes in comparing brain/body size
relations across races. As a result, statements about brain size
differences between races should not rely on adjusted values, and it
is not appropriate to conclude that higher IQ's in Asians are linked
to larger brain size.

The issue of race/brain size/IQ invites a return to the sex/brain
size/IQ issue. Rushton's (1992) data show that the estimated cranial
capacity of Negroid-American men is some 13-14% higher than that of
Caucasoid-American women, even though the average IQ for the former is
presumably lower. How can this be integrated into a model of larger
brain => higher IQ without qualifying the meaning of brain size
comparisons across sexes, or revisiting the issue of what factors
other than brain size have a bearing on IQ? This question once again
emphasizes the unresolved issues of how brain weight/ body parameters
can be compared across sexes, races, and age cohorts.

Finally, the small absolute differences in brain size between
Mongoloids, Caucasoids, and Negroids in Rushton's (1992) data base
should be evaluated relative to cohort data. We have seen that values
from two Air Force samples drawn 17 years apart showed estimated brain
size differences that are larger than the differences reported between
races in the 1988 common age cohort. It is legitimate to ask whether
the contemporary Negroid- and Caucasoid-American samples described in
the common 1988 age cohort could not differ as much from each other in
undefined demographic and nutritional variables as the cohort samples
from 1950 and 1967 differed from each other.

I am not going to address the issue of racial differences in IQ
relative to brain size, because this cannot be resolved here. Clearly,
Rushton & Ankney feel that sufficient evidence is available to make
their point on racial differences in IQ. The issue is not whether such
differences can be observed; they are observed and they are marked and
important for a number of reasons. What to make of them is another
matter. If cohort differences across time and culture complicate
interpretation of brain size differences across races, the additional
uncontrolled effects of community variables in the determination of IQ
(Church & Katigbak, 1991; Coon, Carey & Fulker, 1992; Wachs, Moussa,
Bishry, Yunis, Sobhy, McCabe, Jerome, Galal, Harrison, & Kirksley,
1993) across races render conclusive statements about racial IQ
differences even more difficult, if not impossible at present.



References

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Glenlivet
Wednesday, January 7th, 2004, 06:31 PM
Brain Size Matters: A Reply to Peters

J. PHILIPPE RUSHTON and C. DAVISON ANKNEY

University of Western Ontario

Abstract

Peters (1993) claimed that published research on brain size and
IQ is flawed because it did not meet his list of minimum
conditions that (a) subjects should be matched for height, weight
and age, (b) analyses should be conducted separately within sex,
(c) subjects should not vary in prenatal and nutritional history,
(d) people with IQs appreciably below the population mean of 100
should not be studied, and (e) brain size measures should be done
blind . However, these conditions have either been met or are
unnecessary and/or inappropriate. We show, contrary to Peters'
claims, that (a) brain size is related to mental abilities, (b)
brain size varies by sex and race, and (c) mental abilities vary
by sex and race. Finally, we suggest that brain size constraints
on behavioural complexity may be best understood from an
evolutionary perspective.

In a reply to Lynn (1993) about brain size and IQ, Peters (1993)
charged bias and questionable motives to dismiss relations first
established over 100 years ago. Peters (1993) claimed that studies of
brain size are confounded by systematic bias, including racial bias ,
over and above normal measurement error. Peters (1993) also
conjectured that uni-directional measurement errors may exist and so
he dismissed Rushton's (1992) analyses showing race and sex
differences in cranial capacity in 6,325 U.S. military personnel.
Consequently, Peters claimed that such studies must be done blind ,
i.e., the person doing the measurement should not know the race of the
subject being measured.

Peters did not note, although it was made clear in Rushton's (1992)
paper, that (1) Rushton neither made the measurements nor knew who
did, and (2) measurements were made to determine proper helmet sizes
not brain sizes (i.e., they were done blind , as the measurers were
unaware of the use that Rushton would make of their data). The East
Asian/European/African differences that Rushton (1992) found in
cranial capacity (cm3) using external head measurements are similar to
those found by Beals, Smith, and Dodd (1984) who estimated cm3 from
endocranial volume, and by Ho, Roessmann, Straumfjord, and Monroe
(1980) who weighed brain mass (grams) at autopsy. Does Peters believe
that Ho et al. leaned on their scales, when weighing brains of
European-Americans, by just enough to produce the same difference
caused by extra snug measurements supposedly made by those measuring
heads of African-Americans? Regardless, it is implausible that the
racial bias alleged by Peters would also produce findings that East
Asians have relatively larger brains than do Europeans.

Allometric and nutritional factors

Peters (1993) misstates when and why it is appropriate to correct for
variation in body size (e.g., height or weight) when analyzing human
attributes. It is only appropriate to correct for body size if one
wishes to determine whether two (or more) individuals or groups are
relatively different in some attribute, when it is already known that
they are absolutely different in that attribute and/or in body size.
For example, men and women differ in both absolute brain size and
absolute body size. Thus, it is appropriate to correct for body size
to determine if men have relatively larger brains. But, it would be
inappropriate to correct for body size to determine if men have
absolutely higher IQs.

Consider this simple analogy: John Doe is 178 cm tall and can jump 1 m
off the ground, whereas basketball star Michael Jordan is 208 cm tall
and can jump 1.17 m off the ground. There are two questions that we
can ask from this: (1) For his size, can Michael Jordan jump higher?
(Answer is no he's 17% taller and can jump 17% higher), and (2) Can
Michael Jordan jump higher? (Answer is, obviously, yes).

Now, consider Peters' argument that to determine if larger brains
produce (absolutely) higher IQs, one must correct for body size. This,
as can be seen from the above, makes no sense. A higher IQ is a higher
IQ (just as a higher jump is a higher jump) regardless of body size.
On average, taller people have higher IQ's, not because they are
taller, per se, but because, on average, they have larger brains.
Correcting for body size reduces the question to a nullity, i.e., do
tall people with their larger brains have relatively higher IQ's?

Peters erred similarly when he argued that age must be controlled when
analyzing brain-size/IQ relations in adults. Both brain size (Ho et
al., 1980) and IQ (Brody, 1992) decline after the age of 45 years.
This likely is not coincidental but, regardless, if one corrects for
age then the result would simply be that brains of similar size tend
to produce similar IQ's.

Peters' erroneously stated that subjects in studies of brain-size/IQ
relations should have similar early-life nutrition and be from the
same social class. His rationale is that these factors can affect
brain size. But, the question is do people with smaller brains have
lower IQ's? , not why do they have smaller brains? . It might be
interesting to know why John Doe is shorter than Michael Jordan but,
regardless, he cannot jump as high.

Brain size and intelligence

As Lynn (1993) showed, the IQ/brain-size relation is ubIQuitous.
Studies, additional to those provided by Lynn (1993), show that the
correlation ranges from 0.10 to 0.30 with a mean of about 0.20
(Wickett, Vernon, & Lee, 1994). The head-perimeter/IQ relation occurs
in Orientals as well as whites and blacks and is apparent early in
life. The National Collaborative Perinatal Project (Broman et al.,
1987) found that head perimeter at birth, at 1 year, and at 4 years
correlated with IQ at age 7 from r = 0.13 to 0.24 in 19,000 black and
17,000 white children. Jensen and Johnson (1994) used these data to
show that head size at age 7 (although not at age 4) is correlated
with IQ within-families (i.e., among same-sex full siblings, with age
partialed out), thus indicating a functional relation between brain
size and IQ.

Magnetic resonance imaging technIQues that create a 3-dimensional
model of the brain in vivo confirm the brain-size/IQ relation. Five
studies found an average correlation greater than 0.40, an improvement
over studies that used head perimeter as a measure (Willerman et al.,
1991; Andreasen et al., 1993; Raz et al., 1993; Egan et al., 1994;
Wickett et al., 1994). Peters critIQued the two studies then
available, but only confused the issue. First, he claimed that
Willerman et al.'s (1991) low IQ group, because it averaged only 90.5,
was an improper control . It was, however, not intended to be a
control. Importantly, Willerman et al. showed that those with below
average IQ had, on average, smaller brains. Second, Peters (1993)
almost conceded the brain-size/IQ relation in his footnote citation to
Andreasen et al. (1993). However, even there he suspected bias, i.e.,
self-selection of subjects. But, this could only bias such results if
people with large-brains/high-IQ and small-brains/low-IQ volunteered,
whereas those with large-brains/low-IQ and small- brains/high-IQ did
not. We are unaware of evidence to support such an implausibility.
Regardless, beside studies by Willerman et al. (1991) and Andreasen et
al. (1993) cited by Peters (1993), the brain-size/IQ relation
established using magnetic resonance imaging was corroborated by Raz
et al. (1993), Egan et al. (1994), and Wickett et al. (1994).

The null hypothesis of no relation between brain size and IQ is false.
In anticipation of this, Peters (1993) argued that even if
brain-size/IQ correlations are valid, they account for only a small
percentage of variation. But, it is predictable that correlations
between IQ and overall brain size will be modest. First, much of the
brain is not involved in producing what we call intelligence; thus,
variation in size/mass of that tissue will reduce the correlation.
Second, IQ is an imperfect measure of intelligence and thus, variation
in IQ scores is an imperfect measure of variation in intelligence.

Sex differences

Peters (1993) correctly noted the absolute male/female difference in
brain size. He was, however, incorrect that comparisons of brain size
across sex cannot be made because there are (supposedly) no
appropriate scalars of body size. Ankney (1992) reexamined Ho et al.'s
(1980) autopsy data on 1,261 Americans aged 25 to 80 after excluding
obviously damaged brains. Using allometric technIQues that are
standard in comparative biology, Ankney (1992) found that at any given
surface area or height, brains of European-American men are heavier
than those of European-American women and brains of African-American
men are heavier than those of African-American women. For example,
among 168 cm (5'7 ) tall European-Americans (the approximate overall
mean height for men and women combined), brain mass of men averages
about 100 grams heavier than that of women.

Ankney's (1992) results were confirmed in Rushton's (1992) study of a
stratified random sample of U.S. Army personnel. After adjusting for
effects of age, stature, weight, military rank and race, cranial
capacity of men averaged 1,442 cm3 and women 1,332 cm3. This
difference was found in all of the many analyses that were done to
control for various possible body size effects (see Rushton, 1992).
Moreover, the difference was replicated across samples of
Asian-Americans, European-Americans and African-Americans, as well as
in officers and enlisted personnel.

Peters (1993) correctly noted the paradox that women have
proportionately smaller brains than do men, but apparently have the
same IQ scores. Thus, Ankney (1992) proposed that the sex difference
in brain size relates to those intellectual abilities at which men
excel. Briefly, according to Kimura (1992), women excel in verbal
ability, perceptual speed, and motor coordination within personal
space; men do better on various spatial tests and on tests of
mathematical reasoning. Ankney hypothesized that it may require more
brain tissue to process spatial information. Just as increasing word
processing power in a computer may require extra capacity, increasing
3-dimensional processing, as in graphics, requires a major jump in
capacity. In support of Ankney's hypothesis, although Lynn (1994)
found that men average 4 points higher than do women on standard IQ
tests, Ankney (1995) showed that nearly all of this difference derived
from men's higher scores on spatial and mathematical reasoning
subtests.

Race differences

Rushton (1995) reviewed 100 years of scientific literature and found
that across a triangulation of procedures, brains of East-Asians and
their descendants average about 17 cm3 (1 in3) larger than those of
Europeans and their descendents whose brains average about 80 cm3 (5
in3) larger than those of Africans and their descendents. Although
critics can pick outliers to show counter-examples and suggest
opposite trends (as could critics of a statement that men are, on
average, taller than women) the aggregated data are clear (see
Rushton, 1995, for full discussion of alleged counter examples).

Consider the following statistically significant comparisons. Using
brain mass at autopsy, Ho et al. (1980) summarized data for 1,261
adults (see above) and reported a sex-combined difference between 811
European- Americans with a mean of 1,323 g (sd = 146) and 450
African-Americans with a mean of 1,223 g (sd = 144). Using endocranial
volume, Beals et al. (1984, page 307, Table 5) analyzed 20,000 crania
and found sex-combined brain cases differed by continental area.
Excluding Caucasoid areas of Asia (e.g., India) and Africa (e.g.,
Egypt), 19 East Asian populations averaged 1,415 cm3 (sd = 51), 10
European groups averaged 1,362 cm3 (sd = 35) and 9 African groups
averaged 1,268 cm3 (sd = 85). Using external head measure- ments,
Rushton (1992) found, in a stratified random sample of 6,325 U.S. Army
personnel, measured in 1988 to determine head size for fitting
helmets, Asian-Americans, European-Americans, and African-Americans
averaged 1,416, 1,380, and 1,359 cm3, respectively (see also, Rushton,
1994).

Globally, racial differences in brain size parallel those found in
measured intelligence. Europeans in North America, Europe and
Australasia have mean IQs of around 100. For East Asians, measured in
North America and in Pacific Rim countries, means range from 101 to
111. Africans living south of the Sahara, African-Americans and
African-Caribbeans (including those living in Britain), have mean IQs
of from 70 to 90 (Lynn, 1991). Elementary speed of information
processing in 9- to 12-year-olds, in which children decide which of
several lights stands out from others, show that racial differences in
mental ability are pervasive. All children can perform the tasks in
less than 1 s, but more intelligent children, as measured by
traditional IQ tests, perform the tasks faster than do less
intelligent children. Japanese and Hong Kong children have faster
decision times (controlling for movement time) than do British and
Irish children who have faster decision time than South African Black
and African-American children (Jensen, 1993; Jensen & Whang, 1993;
Lynn, 1991).

Evolutionary considerations

Metabolically, the human brain is an expensive organ. Representing
only 2% of body mass, the brain uses about 5% of basal metabolic rate
in rats, cats, and dogs, about 10% in rhesus monkeys and other
primates, and about 20% in humans. Thus, from an adaptationist
perspective, unless large brains substantially contributed to
evolutionary fitness (defined as increased survival of genes through
successive generations), they would not have evolved.

Paradoxically, Peters (1993) cited Haug (1987) to refute speculations
about the significance of differences in brain size across
individuals, sex, or race , even though Haug (1987, p.135) reported a
correlation of r = 0.479 (n = 81, p < .001) between number of cortical
neurons and brain size including both men and women in the sample.
Haug's analysis showed that a person with a brain size of 1,400 cm3
has, on average, 600 million fewer cortical neurons than an individual
with a brain size of 1,500 cm3. The difference between the low end of
normal (1,000 cm3) and the high end (1,700 cm3) equates to 4.200
billion neurons (a difference of 27% more neurons for a 41% increase
in brain size).

Haug noted that most female data points lay above the regression line
(i.e., women average more neurons for a given brain size than do men).
This suggests that women's brains are differently organized than are
men's, and so causes and results of race differences in brain size may
be different from those of sex differences. Kolakowski and Malina
(1974) hypothesized that differing roles of men and women during human
evolution produced a sexual dichotomy in abilities. Men roamed from
the home base to hunt, which would select for targeting ability and
navigational skills; women were relatively sedentary. Ankney (1992,
1995) expanded on this hypothesis to argue that selection for such
abilities also selected for relatively larger brains in men and that
it may require more brain tissue to process spatial information.

Rushton (1995) provided an evolutionary hypothesis for why East Asians
have the largest brains. The currently accepted view of human origins
posits a beginning in Africa some 200,000 years ago, an
African/non-African split about 110,000 years ago, and a European/East
Asian split about 40,000 years ago (Stringer & Andrews, 1988).
Evolutionary selection pressures were different in the hot savanna
where Africans evolved than in the cold arctic where East Asians
evolved. According to Rushton (1995), the further north the
populations migrated, out of Africa, the more they encountered
cognitively demanding problems of gathering and storing food, gaining
shelter, making clothes, and raising children during prolonged
winters. As the original African populations evolved into Europeans
and East Asians, they did so in the direction of larger brains,
greater intelligence, slower rates of maturation, and other traits
that differentiate these populations.

Conclusion

The evidence is overwhelming that there are racial and sexual
differences in brain size, that there are racial differences in
general IQ, that there are sexual differences in verbal versus
performance IQ, and that differences in mental abilities are related
to differences in brain size. Peters cannot simply deny this evidence.
Thus, important research questions include (1) what is responsible for
the group differences, i.e., are they genetically and/or
environmentally caused?, (2) does the brain size/IQ correlation
indicate cause and effect ?, and (3) is there bidirectional causality
such that the greater learning ability of high IQ children feeds back
to produce even larger brain size?

----------------------------------------------------------------------

References

Andreasen, N.C., Flaum, M., Swayze, V., O'Leary, D.S., Alliger, R.,
Cohen, G., Ehrhardt, J. & Yuh, W.T.C. (1993). Intelligence and brain
structure in normal individuals. American Journal of Psychiatry, 150,
130-134.

Ankney, C.D. (1992). Sex differences in relative brain size: The
mismeasure of woman, too? Intelligence, 16, 329-336.

Ankney, C.D. (1995). Sex differences in brain size and mental
abilities: Comments on R. Lynn and D. Kimura. Personality and
Individual Differences, 18, 423-424.

Beals, K.L., Smith, C.L. & Dodd, S.M. (1984). Brain size, cranial
morphology, climate, and time machines. Current Anthropology, 25,
301-330.

Brody, N. (1992). Intelligence. New York: Academic Press.

Broman, S.H., Nichols, P.L., Shaughnessy, P. & Kennedy, W. (1987).
Retardation in young children. Hillsdale, NJ: Erlbaum.

Egan, V., Chiswick, A., Santosh, C., Naidu, K., Rimmington, J.E., &
Best, J.J.K. (1994). Size isn't everything: A study of brain volume,
intelligence and auditory evoked potentials.Personality and Individual
Differences, 17, 357-367.

Haug, H. (1987). Brain sizes, surfaces, and neuronal sizes of the
cortex cerebri. American Journal of Anatomy, 180, 126-142.

Ho, K.C., Roessmann, U., Straumfjord, J.V., & Monroe, G. (1980).
Analysis of brain weight. Archives of Pathology and Laboratory
Medicine, 104, 635-645.

Jensen, A.R. (1993). Spearman's hypothesis tested with chronometric
information processing tasks.Intelligence, 17, 47-77.

Jensen, A.R., & Johnson, F.W. (1994). Race and sex differences in head
size and IQ.Intelligence, 18, 309-333.

Jensen, A.R., & Whang, P.A. (1993). Reaction times and
intelligence.Journal of Biosocial Science, 25, 397-410.

Kimura, D. (1992). Sex differences in the brain.Scientific American,
267 (No. 3), 119-125.

Kolakowski, D., & Malina, R.M. (1974). Spatial ability, throwing
accuracy, and man's hunting heritage.Nature, 251, 410-412.

Lynn, R. (1991). Race differences in intelligence. Mankind Quarterly,
31, 255-296.

Lynn, R. (1993). Brain size and intelligence in man: A correction to
Peters. Canadian Journal of Experimental Psychology, 47, 748-750.

Lynn, R. (1994). Sex differences in intelligence and brain size.
Personality and Individual Differences, 17, 257-271.

Peters, M. (1993). Still no convincing evidence of a relation between
brain size and intelligence in humans. Canadian Journal of
Experimental Psychology, 47, 751-756.

Raz, N., Torres, I.J., Spencer, W.D., Millman, D., Baertschi, J.C., &
Sarpel, G. (1993). Neuroanatomical correlates of age-sensitive and
age-invariant cognitive abilities. Intelligence, 17, 407-422.

Rushton, J.P. (1992). Cranial capacity related to sex, rank, and race
in a stratified random sample of 6,325 U.S. military personnel.
Intelligence, 16, 401-413.

Rushton, J.P. (1994). Sex and race differences in cranial capacity
from International Labour Office data. Intelligence, 19, 281-294.

Rushton, J.P. (1995). Race, evolution, and behavior. A life-history
perspective. New Brunswick, NJ: Transaction.

Stringer, C.B. & Andrews, P. (1988). Genetic and fossil evidence for
the origin of modern humans. Science, 239, 1263-1268.

Wickett, J.C., Vernon, P.A., & Lee, D.H. (1994). In vivo brain size,
head perimeter, and intelligence in a sample of healthy adult females.
Personality and Individual Differences, 16, 831-838.

Willerman, L., Schultz, R., Rutledge, J.N., & Bigler, E.D. (1991). In
vivo brain size and intelligence. Intelligence, 15, 223-228.

Canadian Journal of Experimental Psychology (Vol. 49, No. 4)

Dr. Solar Wolff
Saturday, January 10th, 2004, 08:19 AM
It was once said that betwen species, brain size mattered but within a species, it did not. This, of course, was the Franz Boas, American anthropological dogma. Now we have Out of Africa and the question arises if we are not really two species, Africans and non-Africans. This throws the old dogma back on its face.

Whites have bigger heads than Blacks. But Blacks have bodies as large or perhaps heavier than Whites. This means allometry comes into play. Allometry was not mentioned as being controlled in the Black-White comparison stated above. This may be a fault in the study. Also, I.Q. differences between American Whites and Blacks become even greater if we consider, for instance, German Whites as the article did. These I.Q. differences were not mentioned, only cranial capacities of various "white" groups as if they were all the same.

FadeTheButcher
Saturday, January 10th, 2004, 03:47 PM
If I recall correctly, the Neanderthals had the biggest brains.

Agrippa
Saturday, January 10th, 2004, 03:54 PM
If I recall correctly, the Neanderthals had the biggest brains.

True, but just compared to the human average. There are many especially Europid and Mongolid people which got bigger brains.

But its not just size but also structure which is even more important for intelligence, especially the Gyri (whorls in English?) of the Neocortex.

Razmig
Saturday, January 10th, 2004, 11:38 PM
True, but just compared to the human average. There are many especially Europid and Mongolid people which got bigger brains.

But its not just size but also structure which is even more important for intelligence, especially the Gyri (whorls in English?) of the Neocortex.
I second that, it is not size, it is the number of folds that increases brain capacity. Great post!

Agrippa
Saturday, January 10th, 2004, 11:55 PM
I second that, it is not size, it is the number of folds that increases brain capacity. Great post!

Thx, but I didnt want to say that brain size doesnt matter (in fact I dont really know but think it matters), but is there are other, maybe even more important factors.

Razmig
Sunday, January 11th, 2004, 12:34 AM
Thx, but I didnt want to say that brain size doesnt matter (in fact I dont really know but think it matters), but is there are other, maybe even more important factors.
Dolphins and some whales have fairly large brains. The density of the brain and its folds is what makes human brains so complex. Also the size of the animal is supposed to have something to do with its brain mass (in Mammals). I think (it's been a long time) I remember in my first anat class that the horse brain is the most similar to a humans (In size), but a monkeys similar in complexity. All humans have the same brain (with different neural stem cell variants).

Agrippa
Sunday, January 11th, 2004, 01:03 AM
Dolphins and some whales have fairly large brains. The density of the brain and its folds is what makes human brains so complex. Also the size of the animal is supposed to have something to do with its brain mass (in Mammals). I think (it's been a long time) I remember in my first anat class that the horse brain is the most similar to a humans (In size), but a monkeys similar in complexity. All humans have the same brain (with different neural stem cell variants).

We speak about intraspecific and not interspecific differences thats obvious I think, so whats the point about a comparison with whales?

If we think about two people with basically the same structure, neuron-density and gyri its obvious that at least in such a case size must matter.

Maybe it has not to lead to more intelligence but more potential from birth.

Razmig
Sunday, January 11th, 2004, 01:06 AM
We speak about intraspecific and not interspecific differences thats obvious I think, so whats the point about a comparison with whales?

If we think about two people with basically the same structure, neuron-density and gyri its obvious that at least in such a case size must matter.

Maybe it has not to lead to more intelligence but more potential from birth.
Taking in consideration that all Humans are Animals, and all Humans are mammals, like whales and dolphins, I'd say it's worth a comparison. Brains do not form differently in species, rather they perform differently. The probable reason behind human brain evolution would be the daunting task of hunting for meat and seeking shelter. I don't think that humans have different brain capacities, as no human head/brain is that different from anothers. Perhaps dolichocephalics have more folds in their brains? I wish I hadn't sold my anatomy books!

Agrippa
Sunday, January 11th, 2004, 03:59 AM
(d) people with IQs appreciably below the population mean of 100
should not be studied

Thats very funny too, because it would mean to ignore the most Negrids. :D

Really this "arguments" against a direct comparison are so weak and just politically motivated that it is just ridiculous.


(c) subjects should not vary in prenatal and nutritional history

That makes sence but just for the comparison of races and not for the question if brain size matters. Because whatever the reason, if the brain is bigger and the intelligence higher it is a correlation no matter which caused it.


(b) analyses should be conducted separately within sex

Thats good too, because its a theme on its own like the article suggests too.
Very interesting arguments which strengthened my personal view on this theme.

But there is much more to do and not all questions are answered so far...we are just at the beginning.
One thing is already obvious, the "just environmental" and "color/race blind" marxist/liberal view is severe damaged and only some "political correct" or indoctrinated people still believe in this shit.

Agrippa
Sunday, January 11th, 2004, 04:06 AM
Taking in consideration that all Humans are Animals, and all Humans are mammals, like whales and dolphins, I'd say it's worth a comparison. Brains do not form differently in species, rather they perform differently. The probable reason behind human brain evolution would be the daunting task of hunting for meat and seeking shelter. I don't think that humans have different brain capacities, as no human head/brain is that different from anothers. Perhaps dolichocephalics have more folds in their brains? I wish I hadn't sold my anatomy books!

I would suggest to buy some basic biologically literature first...

Brains do form differently in Species. The brain of a Dolphin f.e., although big, is formed much more primitive than the human brain.

Like I said structure is very important between completely different Species and maybe individuals/races in mankind too.

If the structure is basically the same size matters and there are big differences in head/brain size.
The question is just if this differences are based not just on individual but also racial differences - the answer is yes.

The other question is, if this differences (individuals and groups) are caused by genetic or environmental factors (f.e. nutrition is important).

I think its never just one reason but everytime both.

Now we work on the issue to determine how big the genetic input is if we talking about brainsize and intelligence.

Razmig
Sunday, January 11th, 2004, 10:53 AM
I would suggest to buy some basic biologically literature first...

Brains do form differently in Species. The brain of a Dolphin f.e., although big, is formed much more primitive than the human brain.

Like I said structure is very important between completely different Species and maybe individuals/races in mankind too.

If the structure is basically the same size matters and there are big differences in head/brain size.
The question is just if this differences are based not just on individual but also racial differences - the answer is yes.

The other question is, if this differences (individuals and groups) are caused by genetic or environmental factors (f.e. nutrition is important).

I think its never just one reason but everytime both.

Now we work on the issue to determine how big the genetic input is if we talking about brainsize and intelligence.
species = race...typo....i have one more semester left for completion of premed (org. bio)
differenciality developes in the individuals life (where hes raised, his environment, etc) if the son of a bushman was raised like a suburban white boy, his brain would then form like that of a suburban white boy...there is no difference in the capacity of human brains, nothing to affect potential IQ levels...thats an absolute lie

Agrippa
Sunday, January 11th, 2004, 01:06 PM
species = race...typo....i have one more semester left for completion of premed (org. bio)
differenciality developes in the individuals life (where hes raised, his environment, etc) if the son of a bushman was raised like a suburban white boy, his brain would then form like that of a suburban white boy...there is no difference in the capacity of human brains, nothing to affect potential IQ levels...thats an absolute lie

Your problem is that you believe to much what the political corrects saying without proving it.

Species = Race just in the damned fucking Anthropology of the Jewish-Anthro in USrael!!!

The idea of a "Human race" is a big, one of the biggest lies on that matter!

Before the 2nd World war no serious and intelligent Anthropologue was speaking of a human race (at least not in the serious scientific community) and almost everyone considered the Neandertaler being a Species on its own.
Maybe with the same relation like horse and donkey or lion and tiger f.e.
(mixture is possible but there are no fertile children)

Just the leftiest and very phantastic anthropologists were speaking of a "Human race" like it is still happening mostly in US because this term is even religious meant sometimes...
The "Human race" blabla...nothing than shit!

Nothing changed on the scientific view after 1945 but the US liberal/leftiest and some Marxists wanted to change everything, not with scientific but mostly with political arguments.
They made it in many parts, right, but that didnt changed the truth!

And today it is even more clear that the humans can be divided into races like it was some decades ago because of the newest genetical foundings.
If you speak about humans in the same way like any other animal than there must be races at least the great races (Europid, Mongolid, Negrid, Australid)

In the animal world oftentimes even groups considered as species which can procreate themselves successful if just together and only geographic barriers stop them from doing so usually.

Then to consider the Humans as "race" is a damned lie and political motivated view on the biological differences of mankind.

BTW especially the brain of the Khoisanids is quite different and more primitive than that of Europids or Mongolids.
That doesnt mean that there couldnt be intelligent individuals in this race, but the definitely got another brain structure not only caused by environmental factors.

Razmig
Sunday, January 11th, 2004, 09:20 PM
Your problem is that you believe to much what the political corrects saying without proving it.

Species = Race just in the damned fucking Anthropology of the Jewish-Anthro in USrael!!!

The idea of a "Human race" is a big, one of the biggest lies on that matter!

Before the 2nd World war no serious and intelligent Anthropologue was speaking of a human race (at least not in the serious scientific community) and almost everyone considered the Neandertaler being a Species on its own.
Maybe with the same relation like horse and donkey or lion and tiger f.e.
(mixture is possible but there are no fertile children)

Just the leftiest and very phantastic anthropologists were speaking of a "Human race" like it is still happening mostly in US because this term is even religious meant sometimes...
The "Human race" blabla...nothing than shit!

Nothing changed on the scientific view after 1945 but the US liberal/leftiest and some Marxists wanted to change everything, not with scientific but mostly with political arguments.
They made it in many parts, right, but that didnt changed the truth!

And today it is even more clear that the humans can be divided into races like it was some decades ago because of the newest genetical foundings.
If you speak about humans in the same way like any other animal than there must be races at least the great races (Europid, Mongolid, Negrid, Australid)

In the animal world oftentimes even groups considered as species which can procreate themselves successful if just together and only geographic barriers stop them from doing so usually.

Then to consider the Humans as "race" is a damned lie and political motivated view on the biological differences of mankind.

BTW especially the brain of the Khoisanids is quite different and more primitive than that of Europids or Mongolids.
That doesnt mean that there couldnt be intelligent individuals in this race, but the definitely got another brain structure not only caused by environmental factors.
Why would the "Jews" lie in this case? They are amongst, if not, one of the most intelligent peoples of the world. If you consider them a "race."

FadeTheButcher
Sunday, January 11th, 2004, 11:21 PM
Women have smaller brains I believe as well, but they are organized differently. The skull can also be deformed too. It was a common practice among the Hunnic women at one time for example. It just goes to show that skull shape and brain size, while important, are not everything and should be viewed within context.

Agrippa
Sunday, January 11th, 2004, 11:35 PM
Women have smaller brains I believe as well, but they are organized differently. The skull can also be deformed too. It was a common practice among the Hunnic women at one time for example. It just goes to show that skull shape and brain size, while important, are not everything and should be viewed within context.

You are basically right.
What you said about the female brain is also something noticed in this article and many others.

But the practise of deformation is something very special and shouldnt be brought as an example for this question.
First the consequences of extreme deformations are not very good examined and secondly I think that the volume of the skull is not changed dramatically, just the form of it.
Just think about a brachycephalic and a dolichocephalic individual with the same capacity.
But however its not a very good example even if I would say too that brainsize is not the only, or even the most important factor for intelligence or certain abilities.

Structure is more important. But as I stated before, if you got two individuals with basically the same structure it seems unlikely that size doesnt matter.

Razmig
Monday, January 12th, 2004, 05:53 AM
Women have smaller brains I believe as well, but they are organized differently. The skull can also be deformed too. It was a common practice among the Hunnic women at one time for example. It just goes to show that skull shape and brain size, while important, are not everything and should be viewed within context.
larger muscle mass = larger brains
does anyone here have a degree of some sort?

Dr. Solar Wolff
Monday, January 12th, 2004, 08:55 AM
I remember seeing anthro. books written in the 20's and 30's stating that Whites had much more complex folds and deeper ones than Blacks or other "inferior races" as the text said.

Some say it is the nerve connections within the brain that also contribute to intelligence. For instance a nuron could be simply connected to the next in a chain or be connected to four, six, or eight others depending on the interconnections.

Razmig
Monday, January 12th, 2004, 11:07 AM
I remember seeing anthro. books written in the 20's and 30's stating that Whites had much more complex folds and deeper ones than Blacks or other "inferior races" as the text said.

Some say it is the nerve connections within the brain that also contribute to intelligence. For instance a nuron could be simply connected to the next in a chain or be connected to four, six, or eight others depending on the interconnections.
The only other race is Mongoloid and they have the best brain capacity when it comes to sceinces and math. So if the Amerinds were Mongoloid, and the Whites conquered them and created Mexicans, why are the Mexicans so...not so smart? heh

SubGnostic
Sunday, January 7th, 2007, 04:33 PM
I've included here only the relevant, major groups, with the exception of arctic peoples, because of the curious fact that they have the largest brains of all of mankind. The figures are explained in the text.

From the book "Race Differences in Intelligence - An Evolutionary Analysis" by Richard Lynn:

"...In the summaries of studies of race differences in intelligence, IQs are given for general intelligence [! "g" in the tables] and, where possible, for the major primary abilities of reasoning, verbal comprehension, and visualization. IQs for general intelligence are obtained either from general intelligence tests that contain a mix of reasoning, verbal, visualization, perceptual, memory, and sometimes other items, or from tests of non-verbal reasoning ability such as the Progressive Matrices, which provide closely similar results to those of tests of general intelligence..."



Intelligence of Indigenous Europeans

Studies of the IQ of Europeans in Europe are summarized in Table 3.1. These IQs are calculated in relation to a British mean of 100 and standard deviation of 15. Twenty-one of the studies were carried out by Buj (1981) on samples of adults from major cities. Most of the remainder are derived from one of the three versions of the Progressive Matrices (CPM, SPM, and APM). Row 61 giving an IQ of 89 for Serbia is probably a shade too low because the sample is described as being from "predominantly lower or lower middle class families" in and around Belgrade (Moyles and Wolins, 1973, p. 372). The range of IQs of the Europeans is from 87 for one of the studies Ireland and 88 for one of the studies in Greece to 107 for one of the studies in Germany and the Netherlands. There are also some inconsistencies in the same countries, where the IQs typically differ by two or three IQ points and in the case of Portugal and Poland by as much as 13 and 14 IQ points. These differences are partly caused by sampling errors and are partly genuine, arising from differences in living standards and possibly from sub-racial differences in Europe. Sampling errors in studies of the intelligence of national populations arise in the same way as in opinion polls on voting intentions, where normally several polls carried out at the same time give results that differ by a few percentage points. We should not search for the meaning of differences of a few IQ points between studies when in many cases these are simply sampling errors. The important thing is to look for general patterns.

The only significant general pattern of the IQs in Europe appears to be that IQs are a little lower in southeast Europe than in the remainder. In the Balkans Iqs are 94 for Romania, 92.5 (the average of the two studies) for Bulgaria, 90 for Croatia, 89 for Serbia, and 92.5 (the average of the four studies) for Greece. The probable explanation for this is that the Balkan peoples are a hybrid population or cline, comprising a genetic mix between Europeans and South Asians in Turkey. Hybrid populations or clines arise in the borderlands between two races as a result of interbreeding. In the Balkans such a cline evolved because of the close geographical proximity between southeast Europe and Turkey, and the occupation of large territories in southeast Europe by Turkey for a number of centuries during the time of the Ottoman empire. This has brought about a mixing of Turkish and European genes with the result that contemporary Turks and Greeks are genetically quite similar. This has been shown by Cavalli-Sforza, Menozzi, and Piazza (1994) in their genetic linkage tree, in which Greeks are shown to be more closely related to Iranians and other southwest Asian peoples than to Italians, Danes, and English. This genetic similarity is also apparent for those in intelligence, for which the IQ of 90 in Turkey is closely similar to those in the range of 90 to 94 in Greece, Romania, Bulgaria, and Croatia in southeast Europe. Because of the peoples of southeast Europe are a cline it is considered appropriate to exclude these in estimating the European IQ. The median IQ of the remaining countries is 99 and is considered the best estimate of the IQ of Europeans.

Apart from the lower IQs in the Balkans, there are three other countries with IQs somewhat lower than the European average. The first is Lithuania, with an IQ of 90-92. Thesse low figures may be sampling errors because they are rather lower than in neighboring Russia (97), Poland (99), and Estonia (99). The second is Ireland, for which the mean IQ of the four studiesis 92. The most probable explanation for this is the long history of emigration in which there has been some tendency for the more intelligent to migrate, leaving the less intelligent behind. This has also occurred in Scotland, Where the average IQ is 97, and in Corsica, where the average IQ is lower than in mainland France (Lynn, 1979,1980). The third country with a slightly depressed IQ is Portugal, for which the two results are IQs of 101 and 88, which can be averaged to 94.5. The depressed IQ in Portugal is consistent with its having the lowest per capita income in western Euopre and its modest intellectual achievement. The Portuguese have only won one Nobel Prize for science out of the 346 awarded during the Period 1901-2003. This was awarded in 1949 to the neurosurgeon Antonio Moniz for the innovation of the operation of prefrontal leucotomy as a treatment for mental illness, and is now considered a desirable therapy. It may be that intelligence in Portugal has been depressed by the admixture of sub-Saharan Africans in the population. Portugal was the only European country to import black slaves from the late fifteenth century onwards for agricultural and domestic work. According to Du Bois (1939, pp. 132-133), in thesixteenth century blacks outnumbered whites in Lisbon and in the plantations of the Algarve in the south of the country. This may be an exaggeration, and it may be that the proportion of blacks has declined in the succeeding centuries. Nevertheless, if the present population of portugal contains 20 percent of African descent and the IQ of the Africans is 70, this would be expected to produce a population with an IQ of 94.

It may be surprising that there does not appear to be much difference between IQs in the twelve former communist countries of Eastern Europe, among which the median is 96, and the 14 countries of western Europe, among which the median is 98.5. The difference is small and not statistically significant, so it seems that although the former communist countries have had much lower living standards for some sixty years following the end of World War II, this has not impaired the intelligence of the populations.

91821 91822 91823



Europeans outside Europe

Europeans have migrated to many parts of the world. Studies of the intelligence of these populations are summarized in Table 3.2. Rows 1 and 2 give IQs of 93 and 98 for Argentina. Row 3 gives an IQ of 97 for Australia based on a standardization of the American Otis test. Roq 4 gives an IQ of 100 for Australia derived from the administration of the SPM to National Servicemen (the IQ of this sample was 102, but because men obtain higher mean IQs than women by approximately 5 IQ points on this test [Lynn and Irwing, 2004], the figure has been reduced to 100). Row 5 gives an IQ of 98 for a sample of young Australian children. Row 6 gives an IQ of 95 for European children in Brazil from Sao Paulo. Row 7 gives an IQ of 97 for Canada obtained from a sample of 7 to 12 year olds. Row 8 gives an IQ of 100 for Canada obtained from the standardization of the WISC-111 on a representative sample of 2200 6-16 year olds.

Row 9 gives an IQ of 99 for Chile based on a study finding that European students at the Universidad Católica de Valparaiso had the same IQ as Austrian students (n=320). Row 10 gives an IQ of 98 for European New Zealand obtained from a standardization of the Otis test in the 1930s. Row 13 gives an IQ of 101 derived from the standardization of the Progressive Matrices. Row 14 gives an IQ of 102 obtained from the Christchurch Child Development Study. Row 15 gives an IQ of 94 for European 16-year-olds in Natal in South Africa. Rows 16 through 21 give six IQs in the range between 99 and 103 for Europeans in the United states compared with those in Britain. The IQ of 100 given in row 20 is derived from the standardization of the WAIS-3 in Britain. Row 22 gives an IQ of 96 from a standardization of the Progressive Matrices in Uruguay. Row 23 gives an IQ of 100 for European 7-year-olds in Zimbabwe.

The median of these IQs is 99, the same as that of Europeans in Europe. The results show that even in the quite poor countries of Latin America (Argentina, Brazil, Colombia, Mexico, and Uruguay), which have per capita incomes about one third of those in North America and Western Europe, the IQs of Europeans are only fractionally below those in affluent nations. This confirms the results in Europe, where the much poorer former communist countries have about the same IQs as the affluent Western countries.

91824



European University Students

Studies of the intelligence of European university students are summarized in Table 3.3. All the samples have IQs of 100 or above, as would be expected, and the median IQ is 105. The principal interest of the results is for comparison with university students in Africa and South Asia, where IQs are typically about 10 to 20 points lower.

91825



Brain Size

We noted in section 1 that IQs are lower in Southeast Europe and in the Iberian Peninsula than in the remainder of Europe. We would expect that these differences would also be present in brain size because of the correlation between brain size and intelligence of 0.40 (Vernon, wickett, Bazana, and Stelmack, 2000). We look now at differences within subpopulations of Europeans to see whether this is the case. The data on brain sizes of a large number of populations collected by Jurgens, Aune, and Pieper (1990) are shown in Table 3.4 together with IQs. Row 1 shows that Europeans in North America have the largest brain size and IQ. Row 2 shows that these are followed by Europeans in North, Central and Eastern Europe. Row 3 shows slightly smaller brain size and IQ in Spain and Portugal. Row 4 shows a continuation of the downward trend with smaller brain size and IQ in Southeast Europe. Row 5 shows a further continuation of the downward trend with smaller brain size and IQ in the Near East obtained from samples of South Asians from Turkey and Iraq. Row 6 shows the lowest brain size and IQ in South Asians in India. Details of the IQs of the South Asians in Turkey, Iraq, and India are given in Chapter 6."

91826



The Evolution of Race Differences in Intelligence - Europeans

Some of the peoples who colonized the Near East between 100 000 and 90 000 years ago migrated northwards and around 60 000 years ago reached the Caucasus, from which they spread to Ukraine and then, around 40 000 years ago, into central and western Europe. Other peoples from Southwest Asia began to colonize Southeast Europe from Anatolia. These peoples evolved into the Europeans with their paler skins and, in the north of Europe, their fair hair and blue eyes. The Europeans were largely isolated from the South Asians and North Africans on the south by the Mediterranean Sea, and on the east by the Black and Caspian Seas, the high mountains of the Caucasus and Himalayas, and the Kara Kum desert in present-day Turkmenistan. In the las ice age, which lasted from around 28 000 to 10 000 years ago, the winter were significantly colder than those in South Asia with the coldest winter month falling to about -5 degrees celsius. The terrain in Europe became similar to that of present-day Alaska and Siberia. The north of England, Germany, Russia, and the whole of Scandinavia were covered with a permanent ice sheet and the remainder of Europe was cold grasslands and tundra with a few clumps of trees in sheltered places.

These cold winters must have been the main selection pressure for an increase in brain size and intelligence of the Europeans that drove the average brain size up to 1 3696cc and their IQ up to 99. Expressing the increase in their brain size as encephalization quotients (EQ) to control for body size, Cutler (1976) has estimated that pre-Würm Europeans had an EQ of 7.3 and by the end of the Würm glaciation they had an EQ of 8.1. When the ice sheets that covered northern Europe receded by about 10 000 years ago the Europeans with their increased intelligence were able to make the Neolithic transition to settled agriculture. However, despite their higher IQ they were not able to develop early civilizations like those built by the South Asians and North Africans because Europe was still cold, was covered with forest, and had heavy soils that were difficult to plough unlike the light soils on whoch the early civilizations were built, and there were no river flood plains to provide annual highly fertile alluvial deposits from which agricultural surpluses could be obtained to support an urban civilization and an intellectual class (Landes, 1998). From around BC 2500 the Europeans overcame these problems in the relatively benign climate of southern Europe, where they developed the first European civilizations in Crete and Greece. From aound BC 700 the Italians began to build a civilization that eventually became the Roman empire and by 200 AD embraced the whole of Europe west of the Rhine and included the Danube basin, the Near East, and North Africa.

These first European civilizations in Greece and Rome surpassed those of the South Asians and North Africans in science, mathematics, technology, literature, philosophy, and the arts. The western Roman Empire collapsed in 455 AD and European culture suffered a setback in the ensuing dark ages, but from about the year 1000 AD it revived and from around the year 1500 the Europeans became the foremost people in virtually all areas of civilization, as extensively documented by Murray (2003).

The genetical processes through which the higher IQs of Europeans have evolved will have consisted of changes in allele frequencies towards a greater proportion of alleles for high intelligence and probably also through the appearance of new mutations for higher intelligence and the rapid spread of these through the population. The probability of new mutations for higher intelligence in the Europeans will have been increased by the stress of the extreme cold to which the Europeans were exposed.

The lower IQs in the range of 90 to 94 in Southeast Europe are probably attributable to some gene flow between South Asians and Europeans across the Dardanelles and Aegean, producing a cline of South Asian and European hybrids in the Balkans with IQs intermediate between those of Europeans (99) and South Asians (84). The same cline is present in Turkey where the IQ of around 90 is only fractionally lower that in the Balkans."



Intelligence of Africans in Sub-Saharan Africa

The first attempt to estimate the intelligence of Africans was made by Galton (1869) on the basis of his own experience of them during his travels in southwest Africa and the accounts of other travelers. He constructed a scale of grades of intelligence in which one grade was equivalent to 10.425 IQ points on the IQ scale. He estimated that Africans were about two grades below the English, giving them an IQ of 79. Subsequent studies of the IQs of general population samples of Africans in in sub-Saharan Africa have shown that this estimate overestimated the African IQ by slightly over one grade.

Studies of the IQs of Africans in sub-Saharan Afica are summarized in Table 4.1. Explanations of the results set out in the table are given when appropriate. Row 1 gives an IQ of 64 for Cameroon for adult workers. Row 2 gives an IQ of 64 for the Central African Republic for young men applying for technical training course at college in city of Bangui during the years 1951-1955. Rows 3 through 5 give IQs of 64 for samples from Congo-Brazzaville collected at the same time in the cities of Brazzaville and Pointe-Noire. Rows 6, 7, 8, 9, and 10 give IQs of 64, 68, 62, 68, and 65 for Congo-Zaire. Row 11 gives an IQ of 59 for Equatorial Guinea. Row 12 gives an IQ of 80 for adults in Ghana. The IQ is exceptionally high for sub-Saharan Africa, possibly because the samplecame from the capital city of Accra; the people in capital cities tend typically have higher IQs than those in the rest of the country, probably because there is a tendency for more intelligent individuals to migrate to the capital; IQs in London and Paris are higher than in the rest of Britain and France (Lynn, 1979, 1980). Row 13 gives an IQ of 62 for a representative sample drawn from the whole of Ghana. Rows 14 and 15 give IQs of 63 and 70 obtained in two studies for Guinea. Rows 16 through 21 give IQs of 69, 75, 69, 76, 89, and 63 for Kenya.

The IQ of 89 in Row 20 for a sample of 7-year-olds tested in 1998 is much higher than the other figures and the IQ of 76 found by the same investigators in their 1984 study (row 19) and than any other IQ in sub-Saharan African populations. Its disparity from the other studies makes its validity questionable because the IQ of 75 given in row 17 is obtained from a standardization of the same test for the whole Kenya carried out in the same year, and the IQ of 69 given in row 19 was also obtained in the same year. These two IQs are typical of those obtained throughout sub-Saharan Africa and are credible. but they cast doubt on the IQ of 89. Furthermore, the gain of 15 IQ points from an IQ of 76 to 89 over the 14-year period is uniquely high in studies of the secular rise of IQs and cannot be accepted as credible. Further, it is difficult to believe that children in Kenya can have a higher IQ than African Americans in the United States, where the IQ has remained constant at approximately 85 since the 1920s but where the living standards and nutrition of Africans are much higher than in Kenya. For these reasons the reported IQ of 89 for Kenya is considered unreliable. The IQ of 63 given in row 21 is an average of 65 for 6-year-olds at school and 61 for those not at school, suggesting that the effect of schooling is to raise the IQ by 4 points.

Row 22 gives an IQ of 82 for Madagascar. Although usually counted as part of sub-Saharan Africa, the population of the island includes a significant number of Southeast Asians originally frim Indonesia who migrated to the island about the first century AD (Cole, 1965). The population also contains Africans and hybrids of the two races. The proportions of the three groups in the population are not precisely known although it is believed that African ancestry predominates. The mean IQ of 82 is higher than that of any of the samples of the Africans in sub-Saharan Africa given in Table 4.1 except for the questionable 89 for Kenya given in row 20. The population's IQ is intermediate between that of around 65-70 of Africans and around 87 of Southeast Asians, although somewhat closer to that of Africans, as would be excpected for a Southeast Asian and African mixed race population in which African genes predominate. There is no apparent environmental explanation for why the IQ of the population of Madacascar should be higher than that throughout mainland sub-Saharan Africa.

Row 23 gives an IQ of 64 for Mozambique. This sample had a mean of 3.5 years schooling and included some individuals from Transkei and Malawi. Row 24 gives an IQ of 70 for Nigeria obtained for children (age not given) attending to schools in the town of Zaria. An elite sample of boysat grammar school (number=179) in the same town obtained an IQ of 81. The test was the Leone Test and is described by the author as "devised by an African for African children" (Farron, 1966, p. 53). The result belies the assertion often made that Africans are handicapped on tests constructed by Europeans. Rows 25 and 26 give IQs of 64 and 69 for two further studies in Nigeria.

Rows 27 and 28 give IQs of 64 for two samples of adults in Sierra Leone. Row 29 gives an IQ of 65 obtained in the first study of the intelligence of Africans in South Africa, carried out in the 1920s. Rows 30 through 41 give IQs in the range between 58 and 77 obtained in twelve later studies. Row 35 gives an IQ of 71 for prison warders who had had between 9-12 years of education. Row 36 gives an IQ of 77, which is the highest for general population samples in sub-Saharan Africa but was obtained from the Draw-a-Man test, which is a rather poor test for general intelligence. Row 39 gives an IQ of 58 for a large sample of 16-year-old Africans in school who had completed approximately ten years schooling. The comparison is with South African Europeans. Row 40 gives an IQ of 69 for a sample of adults described as "competent men, all in long standing employment in a sophisticated environment...." (Nell, 2000, p. 27). Row 41 gives an IQ of 68 for adolescents with a few years of schooling in the Northern Transvaal. Rows 42 and 43 give IQs of 67 and 64 for samples of adolescents at school in Soweto. Row 44 gives an IQ of 67 for third-grade Zulu school children in Natal.
Row 45 gives an IQ of 69 for Sudan obtained for Shilluk children and adolescents described as "one of the primitive Nilotic Negro tribes" (p. 164) in the Southern Sudan. The IQ given is the mean of four tests: the Goddard and Porteus Mazes, Alexander Passalong, and Draw-a-Man. Rows 46, 47, and 48 give IQs of 64, 74, and 73 for three further studies in the Sudan.

Row 49 gives an IQ of 78 for a sample of secondary school students in Tanzania and is exceptionally high for African samples. The author of the study explains that the reason for this is that the sample was highly selected because "the numkber of places in secondary school is extremely limited and eligibility is determined by competitive examination" (Klingelhofer, 1967, p. 207). The high IQ of this sample cannot be regarded as representative. The result is informative in so far as it shows that an elite sample at secondary school has an IQ of 78 and this suggests that the IQs in the range of 65-72 typically found in sub-Saharan Africa are valid. Rows 50 and 51 give IQs of 65 and 72 for two more representative samples in Tanzania and are consistent with those typical in sub-Saharan Africa.

Row 52 fives an IQ of 80 fr Uganda for a selective sample of school-children described by Vernon (1969, p. 182) as "much superior to the East African population in general." This explains why the IQ is higher that that of representative samples in sub-Saharan Africa. Row 53 gives an IQ of 73 for a large and representative sample of Ugandan children. Rows 54 nd 55 give IQs of 77 and 64 for Zambia. Rows 56 and 57 give IQs of 61 and 70 for Zimbabwe obtained by Zindi, an African psychologist at the University of Zimbabwe.

The most striking feature of the IQs of Africans in sub-Sahran Africa is that they are consistently so much lower that those of Europeans set out in Table 3.1 in Chapter 3. The median IQ is 67 and is adopted as the best estimate of the IQ of Africans. With the exception of the IQ of 82 for Madagascar, which is the highest in the table because of the Southeast Asian element in the population, and the IQs of 78 for the elite secondary sample in Tanzania (row 48) and 80 for the secondary sample in Uganda (row 51), and the questionable 89 for Kenya (row 21), all the IQs fall in the range of 59 to 77, while all the European Caucasoid IQs fall in the range of 87 to 105. There is no overlap between the IQs of the two populations. The variations of the African IQs do not appear to vary by geographical location and are probably attributable to sampling and measurement errors. The IQ of Africans has not shown any change since the first study published by Fick (1929) obtained an IQ of 65 for Africans in South Africa. The four most recent studies of Africans in South Africa carried out in the 1990s found virtually identical IQs of 69 (Nell, 2000), 68 (Sonke, 2000), 67 and 64 (Skuy et al., 2001)."

91835 91836 91837
91838



University students in Africa

Twelve studies have been reported of the intelligence of African university students in South Africa. Some of these also give IQs of European students tested at the same time. The studies are summarized in Table 4.2. Row 1 gives an IQ of 75 for African students at Legon University in Ghana tested with the Block Design (Kohs Blocks) test from the Wechsler Test. All the remaining rows give results for South Africa. Row 2 gives an IQ of 84 for African and 103 for European university students calculated in relation to American adult norms given in Raven, Court, and Raven (1994). Rows 3 and 4 give results for students on the Bloxtest and gives the IQs of Africans in relation to South African European student norms of 100. Row 5 gives results for the WAIS-R for students with an average age of 25 years at the African universities of Fort Hare, Zululand, the North, and the Medical University of South Africa. The Verbal IQ was 78 and the Performance IQ 73, showing once again that the Africans have low IQs in all major cognitive abilities and disconfirming the claim sometimes made that Africans are handicapped in language tasks. Row 6 gives an IQ of 100 for science students at the University of the North. Row 7 gives an IQ of 77 for students at a less prestigious African university. Row 8 gives an IQ of 83 for students at the University of the Witwatersrand and the Rans Afrikaans University in Johannesburg. Row 9 gives an IQ of 82 for African students at the Venda University in the Northern Transvaal. The comparison European group was at the University of Tilberg in the Netherlands. Row 10 gives an IQ of 81 for psychology students at the University of the Witwatersrand. Row 11 gives an IQ of 93 for first year engineering students at the University of the Witwatersrand. Row 12 gives an IQ of 99 for a slighlty reduced number of the same students who took the Advanced Progressive Matrices 16 months later. Both Africans and Europeans obtained IQs approximately 6 points higher on the second testing, probably as a practice effect. Row 13 gives an IQ of 101 for a further sample of African engineering students at the University of the Witwatersrand and shows that the African students scored 15 IQ points lower than European whites.

The mean IQs of general student samples shown in rows 1 to 5 and 7 to 9 all fall in the narrow range of 72 to 84 with a median of 81. The IQs of 100 in row 6, 93 in row 11, and 99 in row 12 are higher than the others because they are for science and engineering students who were admitted to the universities on the basis of their performance in entrance tests of mathematics and physics, and these normally have higher reasoning ability than students in most other academic disciplines. For instance, in Iran 18-year-olds studying math scored 10 IQ points higher than those studying literature (Mehryar, Shapurian, and Bassiri, 1972). In Britain, education students with degrees in science scored 9 IQ points higher than those with degrees in arts (Heim, 1968). Th IQs of European students in South Africa are in the range between 100 and 105 and are about the same as those of European students on other countries (see Chapter 3, Table 3.3). The interest of these results is that they show that typical African students who have had some 12 years of school and have gained entry to university obtain IQs in the range of 72-84. Since these are an African cognitive elite, these results suggest that the IQ of about 70 for the general population is valid and about right. The results also show that IQs of African students in South Africa are on average about 20 IQ points lower than those of European students, and that a considerable gap between the IQs of Africans and Europeans remains when they are metched for years of education. African university students have had ten to twelve years of formal education but apart from those studying maths and physics, obtain IQs in the range of 72-84. Their IQs are some 10 to 12 IQ points higher that the African average because they are a select group."

91847



African Americans in the United States

There have been many hundreds of studies of the intelligence of African Americans in the United States. The most important of these are summarized in Table 4.4. Row 1 gives results of the first major study based on military conscripts in World War I tested with the combined Army Alpha and Beta tests that measured non-verbal and verbal IQs and from which the later Wechsler tests were constructed. The number of Europeans was 93 973. Row 2 gives results for military conscripts in World War II and row 3 the results of military conscripts for the Vietnam War. It is noteworthy that the mean IQ of 77 of Africans is lower in World War II and the Vietnam War than in World War I, and is also lower than the average IQ of 85 that is generally given for the mean IQ of African Americans in the United States. Rows 4 through 7 give results of Shuey's compilation of all American studies. Row 4 gives an IQ 87 derived from 17 studies of pre-school children. Row 5 gives an IQ of 85 derived from 26 studies of primary school children using individual tests such as the Stanford-Binet. Row 6 gives an IQ of 85 for primary school children derived from 103 studies for group tests of verbal ability and 41studies of group tests of non-verbal ability. Row 7 gives an IQ of 85 for high school students. Rows 8, 9, and 10 give the results of Osborne and McGurk's (1982) updated summary of American studies published during 1976 through 1980. Row 8 gives an IQ of 80 derived from 66 studies of preschool 3-5 year olds. Row 9 gives an IQ of 87 derived from 126 studies of primary school children and row 10 an IQ of 87 derived from 17 studies of high school students.

Rows 11, 12, and 13 (Broman et al., 1975) give results for large samples not included in the Osborne and McGurk review. Row 11 gives an IQ of 85 for African mothers tested in the National Collaborative Perinatal Project and rows 12 and 13 give IQs of 87 for their children at the age of 4 years and 7 years. Row 14 gives a g IQ of 86 for Africans from the standardization sample of the WISC-R. Row 15 gives IQs of 81 for g, 86 for verbal, and 84 for visualization for employed individuals collected by the United States Employment Service. Row 16 gives African-American IQs of 85 for g, 87 for verbal, and 86 for visualization for a sample in California. Row 17 gives IQs of 85 for g, 87 for verbal ability, and 86 for visualization ability obtained from the standardization sample of the WAIS-R. Row 18 gives an IQ of 82 from the AFQT. Row 19 gives an IQ of 93 from the standardization sample of the K-ABC. Row 20 gives a vocabulary IQ of 85 from the standardization sample of the Peabody Picture Vocabulary Test. Row 21 gives an IQ of 83 from the standardization sample of the Stanford-Binet-4; in this sample African Americans obtained a short-term memory IQ of 89 consistent with a number with a number of other studies finding they do relatively well on short term memory. Row 22 gives an IQ of 85 for 3-year-olds from the standardization sample of the Stanford-Binet-LM. Row 23 gives anIQ of 83 calculated from the first principal component as a measure of g obtained from military personnel. Row 24 gives an IQ of 85 from the standardization sample of the WISC-3. Row 25 gives an IQ of 88 from the standardization sample of the Kaufman Adolescent and Adult Intelligence Test. Row 26 gives an IQ of 81 for a sample of employed individuals collected by the United States Employment Service. Row 27 gives a visualization IQ of 85 derived from the block design subtest of the WISC-R obtained from the national NHANES III sample.

Row 28 gives an IQ of 85 for infants aged 3.0 to 3.4 years from the standardization sample of the Sanfird-Binet-4. Row 29 gives an IQ of 85 for representative sample aged 70 and older from the continental United States (I.e., excluding Alaska and Hawaii). Row 30 gives an IQ of 90 for vocabulary for African adults obtained in the NORC surveys for 1990-96 from a representative sample from the continental United States. This unusually high figure is attributable to the shortnees of the test, consisting of defining the meaning of ten words. Row 31 gives an IQ of 87 from the 1992 National Adult Literacy Survey, a test consisting of verbal comprehension and arithmetic administered to a representative sample from the continental United States.

There are five conclusion to be drawn from the studies of the intelligence of African Americans. First, the median IQ is 85 and is widely accepted as the best estimate of the African-American IQ. This estimate is close to the 83.5 obtained by Roth, Bevier, Bobko, Switzer, and Tyler (2001) from a meta-analysis of 105 studies based on 6 246 729 individuals. The variation in the means obtained in different studies are probably due to sampling, measurement errors, and differences in the abilities measured in different tests. It has been shown in many studies that Africans do relatively well in tests of memory, so the size of the African-European difference reflects to some degree the extent to which memory tests are represented in the IQs. For instance, one of the higher IQs in the table is the 88 obtained in Kaufman's KAIT. This test contains seven subtests, of which one is a memory for faces test that requires the identification of the faces of famous people. On this subtest Africans obtained a mean IQ of 92.5.

Second, the African-American IQ of approximately 85 appears in children aged 3, as can be seen in rows 22 and 28. These results tell against the theory often advanced by environmentalists that poor education and racism are responsible for or contribute to the low IQ of Africans. Even among 2-year-olds Africans have an IQ of 92 (row 19). This is not so low as in the other studies because African infants mature earlier than Europeans up to the age of two years (Lynn, 1998d; Rushton, 2000). It is not until their third year that their IQs fall below that of Europeans and only in their fourth year that their IQ declines to reach their IQ of approximately 85, as shown in rows 22 and 28.

Third, the IQ of approximately 85 of African Americans is substantially higher than the average IQ of 67 of Africans in sub-Saharan Africa. Two factors can explain this difference. The first is that American Africans enjoy a better environment than Africans in Africa in a number of respects, including much higher living standards and better nutrition and health. The second is that African Americans have on the average about 25 percent of European ancestry and this increases their IQ s above that of Africans in Africa (Reed, 1969; Chakraborty, Kamboh, Nwanko, and Ferrell, 1992).

Fourth, in the five studies giving verbal and visualization IQs, American Africans score one or two points higher on the verbal IQs. The verbal IQs appear to be more culturally biased, so this tells against the theory often proposed by environmentalists that Africans perform poorly because the tests are biased against them. This confirms the conclusions reached by McGurk (1953a, 1953b) that African Americans are not more impaired in what were considered culturally biased general information problems and what were considered culturally biased against African Americans.

Fifth, there appears to have been no improvement in the IQs of Africans Americans over the course of the twentieth century. Thus, the median IQ of the fourteen studies carried out from 1980 to 1998 is 85, the same as that of the earlier studies. This conclusion is confirmed by the anscence of any tendency for the African-American-European difference to be smaller in younger age groups. African-European IQ differences at different ages have been reported by Reynolds, Chastain, Kaufman, and McLean (1987) fo the WAIS-R standardization sample collected in 1978. The African Iqs are 86 in 16-19-year-olds, 85 for 20-34 and 35-54-year-olds, and has been no difference in African-American-European intelligence over the period 1974-1996 (Lynn, 1998e). Finally, in the standardization sample of the KAIT (Kaufman Adolescent and Adult Intelligence Test, Kaufman et al., 1994) there was no significant difference between the youngest and oldest age groups. In fact the youngest age group, born between 1980 and 1991, had a slightly lower IQ of 83 compared with an IQ of 88 of the oldest age group, born on average 1921."

91848



Africans in Britain

Africans began to migrate to Britain in substantial nukbers shortly after the end of World War II. The immigrants came mainly from the Caribbean and in the last quarter of the twentieth century a number came from Africa. From the 1960s studies were published of the IQs of African immigrants. The results of these are given in Table 4.5. Row 1 gives an IQ of 88 for what is believed to be the first published result of the children of West Indian Africans and is for a sample of Caribbean children in London, where the majority of these immigrants settled. Row 2 gives an IQ of 82 calculated by Vernon (1969, p. 169) for another sample in London in the 1960s. Row 3 gives a reasoning IQ of 88 and a vocabulary IQ of 82 for West Indian Children compared with European English children attending the same secondary school in the district of Haringey in London; the district is poor and the Euopean children will have scored below the national average, thereby inflating the IQs of the West Indians. To adjust for this the IQ of the Europeans is assumed to be 95. Row 4 gives an IQ of 89 for a sample children in London. Row 5 gives an IQ of 86 for samples of children in Birmingham and in Deptford, London.

Row 6 gives an IQ of 104 for 9 African children taken into institutions as infants because their mothers were unable to look after them. In the same study the IQs of mixed race children and white children also taken into institutions were measured, with the results that the mixed race had an IQ of 110 (n=15) and the whites an IQ of 104 (n=36). The results are out of line with the other results in the table, all of which show African children in Britain have IQs well below whites. Moreover, it would normally be expected that the IQs of the children would be below average intelligence because the mothers were predominantly unskilled and put them into institutions, and would probably have been of below average intelligence. The results that these children had IQs above the average are remarkable and need replication. If they can be confirmed as valid, they suggest that black mothers do not provide such a good environment as the white foster parents who reared these children, but there is little evidence to support this inference. The numer of children (9) was very small and possibly this is just a fluke result.

Row 7 gives an IQ of 86 for a national sample of Afro-Caribbean children in Britain. Rows 8 and 9 give IQs of 73 for children in Britain born in the Caribbean and of 82 for those born in Britain. The IQ of 73 for those born in the Caribbean os closely similar to that of 71 of indigenous Caribbean children given in Table 4.2. Row 10 gives a verbal IQ of 86 for West Indian Children tested with the English Picture Vocabulary Test. Row 11 gives an IQ of 85 for West Indian Children at a comprehensive school in the town of Ilford in Essex; the IQ of 85 is lower than that of Indian sub-continent children in the same school who obtained an IQ of 91; this is the first of a number of studies in Britain finding that Caribbean immigrants have lower IQs than Indian immigrants from the sub-continent. Row 12 gives a vocabulary IQ of 78 for all West Indian children at maintained (public) schools in an education authority in the Midlands.
Row 13 gives an IQ of 86 derived from a reading test on a very large national sample of 12 530 15-year-olds. Row 14 gives an IQ of 85 obtained on a vocabulary test by West Indian children in the north of England compared with 851 Europeans attending the same schools. Row 15 gives an IQ of 86 obtained by West Indian children at school in a town in the Midlands; Indians from the Indian sub-contitent attending the same schools obtained an IQ of 96, showing once again that South Asians in the same environment as Africans obtain higher IQs. Row 16 gives an IQ of 90 for a sample of West Indian children in London. Row 17 gives an IQ of 87 for a sample of West Indian 4-year-olds.

Row 18 gives an IQ of 89 for a national sample of Caribbean children drawn from the whole of Britain born in 1958 and who had been in Britain for more than 4 years; a further group of 39 who had been in Britain for fewer than 4 years obtained an IQ of 83, suggesting that residence in Britain raises the IQs of Caribbean children by around 6 IQ points. It has sometimes been suggested that many of the recent immigrant children from the Caribbean spoke a form of Creole West Indian English that made it hard for them to understand the teachers, but the fact that immigrant West Indians performed about the same on non-verbal reasoning tests as on verbal comprehension makes this unlikely. Row 19 gives an IQ of 92 for a national British sample born in 1970; the high IQ of this sample may indicate that the IQ of Caribbean children has increased slightly, but the subsequent studies in the table show no improvement in the IQs of African children from the 1960s through the 1980s, so this may be a chance result.

Row 20 gives an IQ of 88 for a sample of African schoolchildren in schools of London, the majority of whom had been born in Britain.
Row 21 gives an IQ of 92 for a sample of African schoolchildren in Cambridgeshire. The IQs are in relation to indigenous British children attending the same schools and these are likely to be below national norm because the British of higher socio-economic status tend not to send their children to schools where there are appreciable numbers of immigrants. The effect of this will be to inflate the IQs of the Africans. There are no national norms for the test so the IQ of the Africans in relation to British cannot be accurately calculated. Probably the IQ of the British in this study was about 95, and hence the IQ of the African sample in relations to British national norms woll have been about 87 and therefore about the same as other samples of Africans in Britain. Row 22 gives an IQ of 89 for a sample of 65-75-year-old Africans in London obtained in 1996-98 compared with a national sample of 5 379 indigenous British.

The results of the studies of the intelligence of Africans in Britain raise three points of interest. First, the median IQ of the studies is 86 and is almost exactly the same as the average of 85 of the Africans in the United States. These figures are substantially higher than the median IQ of 67 of Africans in sub-Sahran Africa and of 71 in the Caribbean, from where most Africans in Britain have come in the post-World War II decades. Second, the higher IQ of Africans in Britain is attributable to better environment. This effect is shown in the study by Yule, Berger, Rutter, and Yule (1975) given in rows 7 and 8 showing IQs of 73 for those born in the West Indies and 82 for those born in Britain, suggesting that residence in Britain raises the IQs of Caribbean children by around 9 IQ points. This result is confirmed by the Mackintosh and Mascie-Tayor (1985) study shown in row 18, where the West Indian children from the Caribbean who had been in Britain for more than 4 years had an IQ of 89, while the IQ of a further group of 39 who had been in Britain for fewer than 4 years obtained an IQ of 83, suggesting that residence in Britain raises the IQs of Caribbean children by around 6 IQ points. The two results are quite similar, suggesting that being raised in Britain increases the IQs of Africans by 7-8 IQ points. This increase is probably largely a result of better nutrition and health care and perhaps education, although there seems to be no evidence that education in the West Indies is poorer than in Britain and is sometimes asserted to be better. The effect of improved nutrition for West Indian immigrants was shown by the Yule et al. (1975) study that found that West Indian Africans born in Britain are taller than those born in the Caribbean who had come to Britain some time during childhood, a difference of 0.67d (standard deviation units). Third, the IQ of 87 for a sample of West Indian 4-year-olds given in row 17 is virtually exactly the same as that obtained by older West Indian children at school and shows that the low IQs of West Indian children cannot be blamed on schools, prejudice of teachers, difficulties understanding teachers' spoken English, and so on. This result confirms those found in the United States, that the low IQ of Africans is present in pre-school children."

91850



Africans in the Netherlands

During the second half of the twentieth century a number of Africans migrated to the Netherlands from the former Dutch colony of Surinam in the northeast of South Africa and from the Netherlands Antilles, the former Dutch colony in the Caribbean. Studies of their intelligence are summarized in Table 4.6. Row 1 gives an IQ of 86 for the children of immigrants from Surinam. The test used and the age of the sample are not given. The population of Surinam consists of 35 percent Creoles of mixed African-European ancestry, 10 percent Africans, 33 percent Asian Indian, 16 percent Indonesian, and 3 percent American Indian. The IQ of 86 is about what would be predicted from this racially mixed population because the largest group, the Creoles, would be expected to have an IQ of about midway between Africans in Africa (67) and Northwest Europeans (100), and the second largest group, the Asian Indians, should have an IQ of approximately 82 (see Chapter 6). Row 2 gives an IQ of 84 for a sample of the children of first generation immigrants from Surinam and the Netherlands Antilles. Row 3 gives an IQ of 88 for a sample of the children of second-generation immigrants from Surinam and the Netherlands Antilles. These children have a four-IQ-point gain compared with the children of first generation immigrants shown in row 2. This confirms the studies in Britain showing that second generation immigrants obtain higher IQs than first generation. Row 4 gives an IQ of 85 for a further sample of the children of immigrants from Surinam. The test used and the age of the sample are not given. Row 5 gives an IQ of 83 for another sample of immigrants from Surinam and the Netherlands Antilles. Row 6 gives an IQ of 85 for adult immigrants from Surinam. Row 7 gives an IQ of 85 for immigrants from the Dutch Antilles, whose population is 85 percent African and mixed African-European. The IQs obtained in the studies are closely similar, with a median of 85, the same as that of Africans in the United States."

91849



Estimation of the Genotypic African IQ

The IQs of approximately 67 of the African populations of sub-Saharan Africa shown in Table 4.1 are a function of both genetic and environmental factors. We now undertake the task of estimating the genotypic African IQ. This is the IQ that Africans would have if they were raised in the same environment as Europeans. The starting point of this analysis is the Minnesota Transracial Adoption Study, the results of which are summarized in section 14 and which showed that a 17 IQ point difference between African Americans and Europeans is still present when they are reared in the same family environments. The conclusion to be drawn from this is that the African-American-European IQ difference in the United States is wholly genetically determined. Although this study showed a 17 IQ point African-European IQ difference, it is reasonable to assume that the true African-American-European difference is 15 IQ points, as shown by the numerous studies summarizd in Table 4.4, and that the 17 IQ point difference obtained in this study is a sampling error. We conclude therefore that the genotypic IQ of African Americans is 15 IQ points below that of American Europeans.

The conclusion that African Americans have a genotypic IQ of 85 does not mean that Africans in sub-Saharan Africa also have a gentypic IQ of 85. African Americans are not pure Africans but are a hybrid population with a significant amount of European ancestry. This has been estimated at 25 percent by Reed (1971) and by Chakraborty, Kamboh, Nwamko, and Ferrell (1992). We can estimate that pure Africans in Africa and in the United States have a genotypic IQ of 80 and that this IQ increases by 0.2 IQ points for every 1 percent of Caucasoid genes. Thus, the average African American will have an IQ of 85 (80 + 25 X 0.2 = 85), a figure confirmed by numerous studies summarized in Table 4.4. In the Southeastern states the percentage of European genes among African Americans is quite low. For instance in South Carolina it has been estimated at 6 percent (Workman, 1968) and in Georgia at 11 percent (Reed, 1969). These admixtures of European genes should raise their IQ by 1.2 and 2.2 IQ points, respectively, giving them an IQ of 81.2 and 82.2. This prediction has been confirmed by the study of 1 800 African Americans in five Southeastern states by Kennedy, Van der Reit, and White (1963), which found their IQ on the 1960 Stanford-Binet was 80.7.

African Americans with 50 percent European genes will have an IQ of 90 (80 + {50 by 0.2 = 10} = 90). This is about the mean IQ of African Americans in the Northern states, where the proportion of European ancestry approaches 50 percent. African Americans with 75 percent European genes is very close to the IQ of 94 of the interracial children in the Minnesota Transracial Adoption Study. Europeans with 100 percent European genes will have an IQ at 100.

This estimate of the genotypic African IQ as 80 means that the average IQ that Africans would obtain if the environments in which they were raised were the same as those of Europeans would be 80. Throughout sub-Sahran Africa the mean IQ of Africans is approximately 67, so it can be inferred that adverse environmental conditions in sub-Saharan Africa impair the African IQ by around 13 IQ points."

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The Evolution of Race Differences in Intelligence - Africans

During the last 200 000 years the ancestors of the Africans continued to inhabit the tropical and sub-tropical environments of equatorial sub-Saharan Africa. This environment was not strongly cognitively demanding for them because primates had become adapted to it for some 60 million years. During the evolution of the hominids Homo erectus were largely plant eaters but supplemented their diets with scavenging the carcasses of animals killed by lions, leopards, and cheetahs (Lee, 1968; Tooby and de Vore, 1989). The evolving Africans lived much as hunter-gatherer peoples in tropical and sub-tropical environments do today, subsisting largely on plant foods, of which numerous species are available throughout the year, and on insects and eggs, with only occasional supplementation from animal meats obtained from hunting.

The ready availability of plant foods, insects, and eggs throughout the year meant that the evolving African peoples in tropical and sub-tropical Africa did not have to hunt animals to obtain meat. A conference of anthropologists was convinced in 1966 to debate that Man the Hunter thesis of the importance of hunting for contemporary hunter-gatherers, at which "the consensus of opinion was that meat is of relatively little nutritional importance in the diets of modern tropical foragers" (Stanford and Bunn, 2001, p. 4) In 1999 a similar conference took place at which there was "a consensus that hominid diets were primarily plant based, as they are among modern tropical foragers" (Stanford and Bunn, 2001, p. 356). Hence the Africans had no need to develop the intelligence, skills, tools, and weapons needed for hunting large mammals. Furthermore, the temperature of equatorial Africa varies annually between approximately 32 degrees celsius, in the hottest month and 17 degrees celsius in the coldest, so the African peoples did not encounter the cognitively demanding requirements of having to make needles and thread for making clothes and tents, to make fires and keep them alight, or to prepare and store food for future consumption. It was relatively easy to keep babies, infants, and young children alive because there was no need to provide them with clothing and from quite a young age they were capable of going out and foraging for food bu themselves.

Nevertheless, the brain size of the Africans increased during the last 200 000 or so years from approximately 1 186 to 1 276cc, and it can be reasonably assumed that this entailed an increase in their intelligence to its contemporary value of 67. This increase occurred because of continual directional selection for intelligence, I.e., the more intelligent individuals had more surviving offspring. The genetical processes will have consisted of the increase in the frequencies of the alleles for higher IQs and probably of some mutations for higher intelligence. If these mutations for higher intelligence appeared they would have spread through the population because high intelligence is a fitness charachteristic but they would not have spread so rapidly and extensively as in the races in temperate and cold climates because the selection pressures for higher intelligence were not so strong in the benign climate of equatorial Africa.
The level of intelligence that evolved in the Africans was sufficient for them to make a little progress in the transition from hunter-gathering to settled agriculture, but not sufficient to develop anything that could be called a civilization with a written language and arithmetic, construction of a calendar, cities with substantial stone buildings, and other criteria set out by Baker (1974)."



Intelligence of Indigenous East-Asians

Studies of the intelligence of indigenous East Asians have been made in China, Japan, Hong Kong, South Korea, Taiwan, and also Singapore, where ethnic Chinese make up 76 percent of the population. The results of these studies are summarized in Table 10.1. Rows 1 to 10 give results for the People's Republic of China. Row 1 gives an IQ of 107 from a standardization of the WISC-R in Shanghai. This figure is pobably a little high for China because the IQ in Shanghai is likely to be higher than in China as a whole. Row 2 gives an IQ of 193 for several reasoning tests for 14- and 15-year-olds obtained in the mid-1990s. Row 3 gives an IQ of 101 calculated from a standardization of the Standard Pogressive Matrices in China for the age range from 6 to 15. Row 4 gives an IQ of 104 for 12- and 18-year-olds in Shanghai compared with Americans in Missouri and Georgia. On 10 arithmetic tests of computation and arithmetical reasoning the Chinese scored higher by an average of 1.37d, the equivalent of 20 IQ points. This study also reports a comparison of the performance of elderly Chinese (N=56, age=66) and Americans (N=47, age = 70) in which the Chinese obtained a lower mean IQ than the Americans by 8 points. No information is given of how representative the sampling was and the result is not considered sufficiently reliable for entry in the table. Row 5 gives an IQ of 109 for a test of arithmetical reasoning for a sample of 4-year-old pre-school children in Beijing, compared with a sample of 156 American children. Row 6 gives an IQ of 103 for a drawing test of a person and a horse resembling the Draw-a-Man test; the Chinese children were at school in Beijing and were compared with a sample of 489 British children. Row 7 gives an IQ of 107 for a combined sample of urban and rural children. Row 8 gives an IQ of 103 for a sample of 17-year-olds at high school in Shanghai compared with a sample of 55 American high school students in Columbia, Missouri. Row 9 gives an IQ of 113 for a sample of college students at the East China Normal University in Shanghai compared with a sample of 239 American college students at the University of Missouri. Row 10 gives an IQ of 107 for a sample of 7-8-year-olds at school in Beijing.

Rows 11 through 19 give nine results from Hong Kong. Row 11 gives an IQ of 105 obtained from the Culture Fair Test for a representative sample of Chinese 9-11-year olds attending five primary schoools. Row 12 gives an IQ of 106 obtained for a large sample of 16-year-olds on the AH4 test. There are no satisfactory British norms for this age for this test, so the comparison group is a sample of Canadian 16-year-olds (MacLean and McGhie, 1980). Rows 13 through 16 give IQs of 109, 103, 110, and 108 obtained from the Standard Progressive Matrices. Row 16 gives results for 10-year-olds in which reasoning ability was measured with the SPM, spatial ability with the space relations test from the Primary Mental Abilities Test, and verbal ability by word fluency. This study shows an exaggerated version of typical East Asian pattern of high reasoning IQ (108), higher spatial IQ (114) and weaker verbal IQ (92). Row 17 gives an IQ of 104 obtained from the Culture Fair Test. Row 18 gives the unusually high IQ of 122 for a sample of 9-year-olds. Row 19 gives a closely similar IQ of 120 for the Advanced Progressive Matrices Hong Kong standardization sample, which appears to have been exceptionally well drawn.

Rows 20 through 42 give IQs for studies in Japan. Row 20 gives a Japanese IQ of 102 calculated from the Japanese standardization sample of the WISC and based on five performance tests and digit span (the remaining verbal tests were altered in the Japanese version of the test and therefore not used); the visualization IQ of 102 is calculated from the block design and mazes subtests. Row 21 also gives a Japanese IQ of 102, calculated from the standardization sample of the WAIS and based on digit symbol, block design, and digit span, the only tests that were unaltered in the Japanese version of the test. Row 22 gives a Japanese IQ of 107 fo 5-10 year olds on the MFFT calculated from error scores compared with an American sample numbering 2 676. Row 23 gives a Japanese IQ of 106 for 10 year olds obtained on the Japanese Kyoto Test compared with British children. Row 24 gives an IQ of 108 for a sample of children in Hiroshima for the arithmetic subtest of the WRAT. Row 25 gives an IQ of 112 for Japanese children in Nagoya and Hamamatsu. Row 26 gives an IQ of 107 obtained from the Japanese standardization sample of the Columbia Mental Maturity Scale.

Row 27 gives results of the study by Stevenson and his colleagues that compared 6- and 11-year-olds of samples drawn from the cities of Minneapolis in the United States, Sendai in Japan, and Taipei in Taiwan. While Sendai and Taipei may be acceptable as broadly represenatative of urban children in Japan and Taiwan, the same cannot be said of Minneapolis as representative of American cities. Minneapolis is the principal city in Minnesota and there is considerable evidence that the intelligence level is higher in Minnesota than in the United States as a whole. In the military draft in World Wae I, the whites from Minnesota obtained the highest score on the Army Beta Test of all American states (Montagu, 1945b). In the military draft for the Korean War the percentage found unacceptable in Minnesota for military service on account of low intelligence was the second lowest among the American states (Jensen, 1973, p.107), indicative of a high average intelligence level. In the NAEP (National Assessment of Educational Progress) math test of 8th grade students in 2003, Minnesota achieved the highest score of all the American states (National Center for Education Statistics, 2003). Flynn (1980, p. 107) has calculated that the mean IQ of whites in Minnesota is 105. This is accepted as the best estimate. Hence for a comparison with an American white IQ of 100, 5 IQ points need to be added to the samples from Japan and Taiwan, giving them an IQ of 105 consistent with the results of numerous other studies.

Row 28 gives a general (full scale) IQ of 103 derived from the Japanese standardization samples of the WISC-R, a verbal IQ of 100 based on the five verbal subtests, and a visualization IQ of 109 based on four performance subtests. Row 30 gives IQs of 103 for reasoning, 103 for verbal, and 107 for visualization ability obtained from the administration of the Kyoto Test to a representative sample of British children; the three IQs have been averaged to give an IQ of 104 for general IQ. Row 31 gives IQs of 104 for reasoning and 114 for visualization ability obtained from the administration of the DAT to a sample of Japanese 13-15-year-olds. Row 32 gives a general IQ of 103, IQs of 102 for "sequential processing" (approximately equivalent to verbal ability), and 105 for "simultaneous processing" (approximately equivalent to visualization ability), calculated from the Japanesestandardization sample of the McCarthy test. Row 33 gives an IQ of 103 derived from Kaufman et al.'s (1989) analyses of the Japanese WISC-R standardization sample forKaufman's sequential and simultaneous factors. "Sequential processing" (an approximate measure of verbal ability) correlated 0.44 with the Wechsler verbal IQ, and "simulataneous processing" (an approximate measure of visualization ability) correlated 0.73 with the Wechsler performance IQ. The rwo IQs are averaged to give a measure of g. In addition, the test contains a matrix analogies test similar to the Progresive Matrices, the results of which are entered in the table under reasoning. Row 34 gives an IQ of 113 for a sample of adolescents in school in Keio compared with 121 American students in school in Florida; the verbal IQ of 116 is calculated from a test of arithmetic and the visualization IQ of 110 from tests of mental rotation and mazes. Row 35 gives an IQ of 110 for a sample of 9-year-old children in Tokyo. Row 36 compares Japanese children in the city of Nagoya with Cancadian norms on the Canadian Cognitive Abilities Test (CCAT). The mean Japanese reasoning IQ of 106 is typical of a number of other studies, but the Japanese verbal IQ of 121 is an unusually high figure for Japanese children. This study also found a quantative IQ of 112 for Japanese children. The children's age range was 5 to 7 years and the advantage of the Japanese 5-year-oldswas as great as that of the 6-7-year-olds. The 5-year-olds were at kindergarten. The high IQs obtained by Japanese 5-year-olds makes it improbable that the Japanese advantage can be an effect of more efficient schooling, as proposed by Stevenson et. al (1985). Row 37 compares Japanese children in the medium-sized city of Matsuyama with American norms on the Matrix Analogies Test and gives the Japanese children a mean IQ of 105.

Row 38 gives an IQ of 103 for reasoning and 109 for visualization obtained for 14-15-year-olds as averages of several tests in the mid-1990s. This result is part of the same study that found an IQ of 103 for children of the same age in China, suggesting that by the mid-1990s the IQs of Chinese and Japanese were the same. Row 39 gives a verbal IQ of 100 derived from a general knoweledge test given to 6- and 17-year-olds in the Japanese city of Sendai compared with the American city of Minneapolis. Because the mean IQ of whites in Minneapolis is estimated at 105, as explained in the comment on row 27, the Japanese mean has been raised by 5 IQ points. Row 40 gives a visualization IQ of 102 obtained by comparing a sample of Japanese high school and university students with a sample of 52 European students at University College, Dublin. Row 41 gives an IQ of 102 obtained for Japanese 7- and 11-year-olds compared with a matched sample of 60 British children. Row 42 gives a verbal IQ of 105 derived from a general knoweledge test comparing Japanese 17-year-olds with Americans in Minneapolis; the Japanese mean has been raised by 5 IQ points for the reason given in the comment on row 38.

Rows 43 and 44 give results for Singapore. Row 43 gives an IQ of 107 for a sample of 13-year-olds. Row 44 gives an IQ of 114 for 15-year-olds obtained from the Advanced Progressive Matrices and is substantially higher, although it is not so high as the two last studies from Hong Kong. Rows 45 through 48 give four results for South Korea. Row 45 gives an IQ of 113 derived from the standardization sample of the Kaufman K-ABC test, an exceptionally well-constructed and standardized American test. This study shows the typical East Asian pattern of high reasoning IQ (110) obtained from a matrix analogies test, high spatial IQ (120), and weaker verbal IQ (106). Row 46 gives an IQ of 109 and a similar pattern of lower verbal than visualization abilities. Row 47 gives an IQ of 103 for a socially representative sample of 4-year-olds at pre-school in the region of Busan compared with 156 American children. Row 48 gives an IQ of 100 based on the standardization sample of WISC-III.

Rows 49 through 59 give eleven results for Taiwan. Row 49 gives an IQ of 102 obtained from an early result in the 1050s. Rows 50, 51, and 52 give IQs of 102, 110, and 105 obtained by primary school children. Row 53 gives an IQ of 107 for a sample of children in Taipei for the arithmetic subtest of the WRAT. Row 54 gives an IQ of 104 obtained from a comparison of Taiwanese children with an American sample in Minneapolis, where the mean IQ of whites is estimated at 105 (as explained in the comment on row 27) so the Taiwanese mean has been raised by 5 IQ points. Row 55 gives an IQ of 105 for 6-8-year-old primary school children in Taipei and country towns and villages. Row 56 gives an IQ of 100 for a general information or knoweledge test given to samples from the United States (N = 1 052) and Taipei in Taiwan. General knoweledge is a component of verbal intelligence, as shown in numerous factor analyses of the Wechsler tests (see also Carroll, 1993), and the results are entered under verbal IQ. Rows 57 and 58 give IQs of 105 for non-verbal reasoning. Row 59 gives an IQ of 107 for a general knoweledge test given to sample in the United States (N = 1 052) and Taipei. The Taiwanese sample scored 2 IQ points higher than the American, but the American sample was taken from the city of Minneapolis where the mean IQ of whites is estimated at 105 (as explained in the comment on row 27) so the Taiwanese mean has been raised by 5 IQ points to 107. The median IQ of the eleven studies for Taiwan is 105.

Two conclusions can be drawn from the studies summarized in Table 10.1. The first is that all the East Asian IQs are a little higher than those of Europeans, except for the Chen et al. (1996) studies of general information in Japan and Taiwan, and the Georges et al. (2003) result for South Korea, all of which gave East Asians an IQ of 100. The range of IQs is between 100 and 122. The median IQ of the students is 105 and should be taken as the best estimate of the IQs of indigenous East Asians. Second, eleven of the studies contain measures of verbal and visualization abilities and in ten of these the visualization IQ is greater than the verbal IQ (the study in row 36 is the exception). The mean and median differences between those two abilities are both 12 IQ points. This difference appears in variety of tests. The finding of the stronger visualization abilities and weaker verbal abilities of East Asians as compared with Europeans is so consistently present and is so large that it appears to be a real phenomenon."

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Brain Size

Studies of differences in brain size between East Asians and Europeans are summarized in Table 10.8. The means and standard deviations are for brain volume in cubic centimeters. Row 1 gives the results calculated by Gould (1981) from the collection of skulls assembled in the early nineteenth century bu the American physician Samuel Morton (1849), who categorized them by race and calculated their average cranial capacities. Gould accused Morton of mistakes and re-measured the skulls, proving to his own satisfaction that the East Asians and Europeans had the same brain size. However, the number of skulls was very low, consisting of 10 East Asians and 52 Europeans, and is so few that little weight can be attached to it. They are given here largely for historical interest.

Row 2 gives results from the largest collection of skulls ever collected, numbering approximately 20 000, and shows that the East Asians had a larger brain size than the Europeans by 1.2d (standard deviation units). Row 3 gives a difference of 20cc from a study of American 7-year-olds children carried out by Broman, Nichols, Shaughnessy, and Kennedy (1987) The brain sizes have been calculated from their data by Rushton (1997). Row 4 gives the results of data assembled by Jurgens, Aune, and Pieper (1990) for many thousands of 25-45-year-olds. The figures in the table have been adjusted for body size by Rushton (2000). Row 5 gives the results of a data set assembled by Groves (1991) by combining estimates of cranial capacities of 36 samples of males from figures given by Coon, Molnar, and Martin, and Saller. The brain sizes are lerger than in row 2 because they are for men but the European-Northeast Asian difference is similar, although slightly larger. Row 6 gives Rushton's results for brain size adjusted for body size for 6 325 United States military personnel. Row 7 gives Rushton's summary of a large number of data sets for brain size adjusted for body size. Thus, all the studies except Morton's, revised by Gould shown in row 1, have found that the East Asians have larger average brain size than Europeans."

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Environmental and Genetic Explanations of the East Asian IQ

The consistently high IQs obtained by East Asians in their indigenous habitats in East Asia and in Europe and the Americas have presented a problem for environmentalists. These have found it relatively easy to explain the low IQs of Afrcans that they could ascribe to poverty, poor education, test bias, and racism. None of these can explain the lower IQ of Europeans compared with East Asians. Environmentalists have adopted three strategies to deal with this problem. The first is to ignore it. This is the solution adopted in most general textbook and in specialist books on race and intelligence by Fish (2002), Gould (1996), and Montagu (1999). The second strategy is to dispute or belittle it. Thus, shortly after the first study of the high IQ of the Japanese on the WISC-R was published, Stevenson and Azuma (1983) contended that the Japanese standardization sample under-represented lower IQ groups.

Later, as more studies were published confirming the high IQ of the Japanese, it was no longer possible to dispute it, so environmentalists contended that the difference was only small. Thus, Brody (2000, p. 219) writes of the studies finding that intelligence in Japan is higher than in the United States, "there is little or no evidence that there are large differences in IQ between the two groups." He does not specify what he means by large. In similar vein, Mackintosh (1998, p. 168) writes "there is no good reason to believe that Chinese of Japanese seriously outscore whites on intelligence tests." He does not specify what he means by seriously. The third strategy adopted by environmentalists is to contend that even if it is conceded that East Asians have higher IQs that Europeans "there is no evidence to decide whether such differences are environmental or genetic in origin" (Mackintosh, 1998, p. 168).

Contrary to this contention, the studies summarized in this chapter point to a strong genetic determination of the higher IQs of the East Asians as compared with Europeans.

First, there is the consistency of the higher IQs of the East Asians than those of the Europeans in so many different locations, including China, Japan, Hong Kong, Singapore, South Korea, and Hong Kong (summarized in Table 10.1).

Second, the high IQs obtained by East Asians in their native lands are in general confirmed by studies of East Asians outside East Asia summarized in Table 10.2. In the United States, the median IQ of East Asians derived from all the studies is 101, a little lower than the 105 of indigenous East Asians in East Asia. There are two possible reasons for this. The first is that those who migrated to the United States could have had slightly lower than average IQs than those who remained in Asia. The second is that the first and second generations of immigrants generally continue to speak their own language and English as a second language. This may handicap them in language tests. The mean IQ of the last six studies in Table 10.2 published from 1990 onwards is 105, the same as that of East Asians in East Asia.

In Table 10.3 we see that East Asians consistently obtain slightly higher average IQs than Europeans in similar environments. In Brazil, the IQ of 99 of ethnic Japanese is 4 IQ points higher than that of Europeans (see Table 3.2), although the Japanese were brought in to work as agricultural laborers after the abolition of slavery in 1888 and are unlikely to have had higher IQs than the general population in Japan. In Britain, East Asians obtained an IQ of 107, and in the Netherlands an IQ of 102. In Malaysia, they obtain an IQ of 99, 10 IQ points higher than that of the indigenous Malays.

Third, environmentalists do not offer any explanation for the consistently high IQ of East Asians, and it is doubtful whether any credible environmental explanation can be found. Intelligence is affected by living standards, but the living standards of a number of East Asians have been lower than those of Europeans. The East Asians of Japan, Hong Kong, and Singapore enjoy comparable living standards to those of Europeans in northern and western Europe, the United States, Canada, Australia, and New Zealand, but the living standards of those in China, South Korea, and Taiwan have been much lower, yet their IQs are about 5 IQ points higher than those of Europeans. The difference is consistently present and there is no plausible environmental explanation for the East Asian superiority.

Fourth, the six studies of the intelligence of Korean infants adopted by European families in Europe and the United States summarized in Table 10.4 all show that these children have higher IQs than those of the Europeans in whose environment they have been reared. It seems improbable that these infants given up for adoption were a selective sample with higher than average IQs. It should however be noted that these children were quite young and would probably have been adopted largely by middle class families that would have given them some environmental advantage. Just how large this effect is likely to have been is difficult to assess, but it is unlikely that it can have been as much as the 11 IQ point advantage of the four adequately nourished samples of adopted East Asians. In the Weinberg, Scarr, and Waldman (1992) study summarized in section 13 of Chapter 4, it was shown that black infants adopted by white midle class families obtained an IQ of 95 at age 7 and of 89 at age 17, suggesting that the environmental advantage for the 7-year-olds was 6 IQ points. Applying the same rule of thumb to the adopted East Asian children, the mean IQ of the adequately nourished samples of 111 should be reduced by 6 IQ points to give a true IQ of 105, precisely the same as that of indigenous East Asians.

Fifth, the faster reaction times of East Asian children shown in Table 10.6 indicate that they have a more efficient neurological processing system that makes a significant contribution to their higher IQs, and again this superiority in reaction times cannot be plausibly explained environmentally. Sixth, several studies summarized in Table 10.8 have shown that East Asians have a larger average brain size than Europeans. Brain size is a significant neurological determinant of intelligence and brain size has a high heritability. It is doubtful whether any environmental explanation is possible for the larger brain size of East Asians. It can be estimated that their larger brain size should give East Asians a 10 IQ point advantage. This is the IQ advantage that they would be expected to have by virtue of their larger brain size if they were reared in the same environments as Europeans. As the IQ of Europeans has been estimated as 99 and the IQ of East Asians as 105, the actual IQ difference between them is 6.0 IQ points. Two explanations can be offered for the fact that the actual East Asian advantage is only 6 IQ points while the predicted advantage is 10 IQ points. First, some of the larger East Asian brain may be devoted to their higher visual memory, which is not measured in intelligence tests. Second, many of the samples were conceived and reared in poorer environments with lower living standards than those of Europeans, and these may have had some depressing effect on their IQs. If this is so, when the living standards of East Asia become equal to those of Europeans, it can be predicted that the IQ difference will become 10 IQ points and will be explicable in terms of the brain size difference."

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The Evolution of Race Differences in Intelligence - East Asians

Some of the peoples of South and Central Asia began to colonize Northeast Asia in the region of present-day China between 60 000 and 50 000 years ago where thay evolved into the East Asians and later into the Arctic Peoples of the far Northeast. The archaic East Asians were largel isolated from the Europeans by the Gobi desert to the west and from the South Asians by the Himalayas to the south. The winters to which they were exposed were much more severe than in South Asia and somewhat more severe than in Europe, with coldest winter temperatures falling to about -12 degrees celsius during the main Würm glaciation.

The reasons for the intense winter cold in Northeast Asia as compared with Europe is that Northeast Asia is a much larger land mass while Europe is much smaller, and that Europe is warmed by prevailing westerly winds from the Atlantic. It was in response to the cold winters that the East Asians evolved the cold adaptations of the flattened nose to prevent frostbite, the shorter legs and thick trunk to conserve heat, the subcutaneous layer of fat that gives the skin a yellowish appearance, the sparse facial hair in men (because profuse beards would freeze and produce frostbite), and the epicanthic eye-fold to mitigate the effect of dazzle of reflected light from snow and ice. The severe winters would have acted as a strong selection for increased intelligence and raised the IQ of the East Asian people s to 105. The genetic processes involved probably consisted of an increase in the frequencies of the alleles for higher intelligence and also of new mutations for higher intelligence resulting from chance and from severe cold stress. The appearance of new mutations may explain why East Asians have particularly strong visualization abilities, as compared with Europeans. New mutations for enhanced visualization abilities may have appeared in East Asias and spread through the population because they were useful for hunting, tool making, and navigation over long distances through featureless terrain.

As with the Europeans, it is probable that most of the increase in the intelligence of the East Asians occurred during the main Würm glaciation. This will have acted as the selection pressure for greater brain size and must have driven their IQ up to its present value of 105. It was not until after the end of the Würm glaciation that their intelligence reached the level at which they were able to make the Neolithic transition to settled agriculture and then to build the civilization in the valley of the Yellow river and the subsequent developments of civilizations in China, Japan, and Korea. During the period between around 0-1500 AD the Chinese built impressive civilizations that were in some respects in advance of those in Europe. For instance, the Chinese invented printing, paper, paper money, gunpowder, the magnetic compass, and the construction of canals with locks several centuries before the Europeans. During the period from 1500 to the present, however, the intellectual achievements of the East Asians have been less impressive than those of Europeans, as has been exhaustively documented by Murray (2003). Historians regard this as a major puzzle to which there is no consensus solution. One factor may be that the East Asians have evolved a higher degree of social conformity than the Europeans, documented by Allik and Realo (2004), and also expressed in their low level of psychopathic personality that I have documented in Lynn (2002). A low level of social conformity and an element of psychopathic personality appear to be ingredients in creative achievement because they reduce anxiety about social disapproval and appear to facilitate the generation of the original ideas that are required for the highest levels of scientific discovery. Another factor may be the historical accident suggested by Weede and Kampf (2002) that throughout much of its history China was a single state whose autocratic rulers were able to suppress liberties, including freedom of thought, more effectively than the rulers of the numerous European states, who were forced by competition to concede liberties to their peoples."



Arctic Peoples

The Arctic Peoples are the indigenous Inuit (formerly known as the Eskimos) of Alaska, the north coast of Canada, and Greenland, the Aleuts of the Aleutian Islands, and the North Turkic and Chukchi peoples of the far northeast of Asia. They are identified as a distinctive genetic "cluster" by Cavalli-Sforza, Menozzi, and Piazza (1994) in their classification of peoples based on a number of genetic markers. The Arctic Peoples differ genetically from the Amerindians in having an appreciable percentage of the B blood group, which is absent in the Amerindians. They differ from the Amerindians and from the East Asians in that they are more highly cold adapted, with shorter legs and arms and a thick trunk to conserve heat, a more pronounced epicanthic eye-fold, and a nose well flattened into the face to reduce the risk of frostbite. The reason the Arctic Peoples have evolved into a distinctive race is that their ancestors were isolated from the East Asians by the Chersky mountain range in northeast Asia. The Inuit split off from the Chukchi people of northwest Russia when they migrated across the Bering Straits into North America about BC 11-10 000. Several of their prehistoric sites have been found in the Nenana river valley in Central Alaska, where their artefacts have been dated between 11 300 to 10 000 years ago (Dixon, 1999). In the mid-twentieth century there were approximately 50 000 Inuit and approximately 5 600 Aleutians.



Intelligence of Arctic Peoples

Studies of the intelligence of Arctic Peoples are summarized in Table 11.1. Row 1 gives an IQ of 89 for the first study of a large sample of Inuit children tested with the Goodenough Draw-A-Man (DAM) Test. Row 2 gives an IQ of 92 for a sample of Aleutian children also tested with the DAM by the same author. This is the only study of the intelligence of Aleutian children. All the other studies are of Inuit. Rows 3 and 4 give results of a study of the IQs of representative samples of primary and secondary Inuit school children in the Yukon and Northwest Territories of Canada tested in 1962. The primary school children obtained an IQ of 94 and the secondary school children and IQ of 84. Row 5 gives the lowest Iq of the series of 78 for a sample of young adults and is so much out of line with the other results that it should be regarded as spurious. Row 6 gives Inuit adults a visualization IQ of 93. Row 7 gives an IQ of 91 for 10-year-olds. Row 8 gives an IQ of 90 obtained by Vernon from the tests of matrices, vocabulary, and Koh's Blocks. The low IQ of 80 for vocabulary may be spuriously low because the children may have spoken their native language at home. The IQ of 90 for reasoning has been entered as the most reasonable figure for general intelligence. In this study Vernon also gave the DAM test, on which the Inuit children obtained an IQ of 95. This is broadly consistent with the results in Rows 1 and 2, in which Arctic children obtained DAM IQs of 89 and 92.

Row 9 gives an IQ of 91 for a substantial sample of 6-12-year-olds obtained from the performance scale of the WISC; these children obtained much lower verbal IQs but they did not speak English as their first language and their low verbal IQs cannot be regarded as valid. Row 10 gives a resoning IQ of 96 for a sample of 9-12-year-olds. Row 11 gives verbal and performance IQs of 78 and 83 respectively for a small sample of 7-year-olds tested with the WPPSI. The children spoke English as a second language, so the verbal IQ is spuriously low and the performance IQ of 93 is entered as the best measure of general intelligence. Row 12 gives a reasoning IQ of 95 for a sample of 7-10-year-olds. Row 13 gives an IQ of 91 for a substantial sample of 7-14-year-olds obtained from the performance scale of the WISC-R. The verbal scale was not given because the children did not speak English as their first language. Row 14 gives an IQ of 92 for Inuit 5-year-olds living in Arctic Quebec. The authors claim that the Inuit children scored higher than Americans, but this is because American norms are depressed by the inclusion of ethnic minorities and because they made no allowance for the secular increase of scores (the children were also given repeated testing at the ages of 6 and 7 in which they made gains attributable to practice effects). Row 15 gives a non-verbal reasoning IQ of 86 and a vocabulary IQ of 77 for Inuit 15-year-olds in Alaska."

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"The median IQ of the studies is 91 and is proposed as the best estimate of the intelligence of the Arctic Peoples. The visualization IQs are somewhat higher than the verbal IQs as shown in Vernon's sample given in row 8, where the visualization IQ is 88 and the verbal IQ 80 and again in the Taylor & Skanes study given in row 11, where the visualization IQ is 93 and the verbal IQ is 78. Averaging the two results gives a visualization IQ 11 higher than the verbal IQ. This high visualization-low verbal pattern is also present in the related East Asian and Amerindian Peoples. It appears that there has been no tendency for the intelligence of Inuit to improve over the period of approximately 60 years from the early 1930s, when the first study by Eells (1933) found an IQ of 89, to the last study in the early 1990s, when Wilgosh et al. (1986) found an IQ of 91."


Visual memory

The Inuit have an unusually strong visual memory ability that is not measured in standard intelligence tests. This was shown by Kleinfeld (1971) in a study of the visual memory of 125 Inuit village children in Alaska aged 9-16 compared with 501 white children in Anchorage and Fairbanks, the two principal towns in Alaska. The test consisted of the presentation of drawings for a brief period of time, after which the children were given the task of drawing them from memory. The Inuit children obtained a mean IQ of 106 in relation to a white mean of 100. Kleinfeld (p. 133) observes that this test result is consistent with the observations of travelers who have accompanied Inuit on long hunting expeditions. She writes that "Caucasians who have traveled with Inuit frequently remark on their extraordinary ability to travel through what seems to be featureless terrain by closely observing the smallest landmarks and memorizing their spatial locations."

The strong visual memory of Inuit may explain why they are relatively good at spelling. In Vernon's (1969) study
he found that Inuit 10-year-olds had a spelling IQ of 95, considerably higher than their verbal IQ of 80, of which spelling is generally considered a component (Carroll, 1993). Good visual memory helps spelling because it makes it possible to recall the shapes of words. This is probably why females are much better at spelling than males (Lynn, 1992): they have better visual memories (Halpern, 2000; Kimura, 2002).

It is likely that the strong visual memory of the Inuit has a genetic basis. It has been found by Osborne and Gregor (1966) that visual memory has a high heritability. Even 9-year-old Inuit children had significantly better visual memory than Europeans, and it seems unlikely that children of this young age would have acquired this strong ability through training, even if it is possible. The most probable explanation for the strong visual memory of Inuit children is that this ability developed genetically through natural selection because of the need for Arctic Peoples to remember fine details of the alndscape in order to find their way home after going out on long hunting expeditions. The landscape of the frozen tundra provides few disctinctive cues, so hunters would need to note and remember such few features as do exist. The strong visual memory of the Inuit is also present in the East Asians (IQ 107) (Chpter 10, Section 7) and Native Americans, for whom Lombardi (1970) found an IQ of 104, very close to the IQ of 106 found by Kleinfeld for Inuit. Possibly the ancestral population of northeast Asia evolved strong visual memory before they diverged into the East Asians, Native Americans, and Arctic Peoples. The strong visual memory of the Inuit has a parallel with that in the Australian Aborigines reported by Kearins (1981) and explained as an adaptation to living in deserts with few landmarks and similar in this regard to the frozen tundra of the Arctic.



Brain Size

It has only proved possible to find one study of the brain size of Arctic Peoples. Smith and Beals (1990) give brain sizes for ten populations of which the mean is 1 444cc. They give a brain size for Europeans of 1 368cc. The difference of 76cc is substantial. Brain size is associated with intelligence among individuals and the same association would be expected to hold between groups. The larger brain size of the Arctic Peoples leads to the expectation that they would have higher IQs than Europeans, yet this is not the case.
There are two probable explanations for this anomaly. First, some of the large brain size of the Arctic Peoples is likely devoted to their strong visual memory found by Kleinfeld (1971) and summarized in Section 2. Second, brain size is not the sole determinant of intelligence. Some neurophysiological processes for higher intelligence may have evolved in the Europeans as a result of genetic mutations but failed to appear in the Arctic Peoples. The reason for this is probably that the Europeans were much more numerous so that the chances of favorable mutations for greater intelligence were greater.


Genotypic Intelligence

It seems probable that both genetic and environmental factors contribute to the low IQ of the Arctic Peoples. There are two lines of evidence suggesting some genetic determination. First, as noted in Section 1, the IQ of the Arctic Peoples has not shown any increase relative to that of Europeans since the early 1930s, although their environment has improved in so far as in the second half of the twentieth century they received improved welfare payments and education. If the intelligence of the Arctic Peoples had been impaired by adverse environmental conditions in the 1930s it should have increased by the early 1980s. Second, in all the studies summarized in Table 11.1 the Arctic children were at school and thus familiar with test taking procedures, so there is no reason to suppse that they were handicapped in this regard."


The Evolution of Race Differences in Intelligence - Arctic Peoples

Sometime between 50 000-40 000 years ago some of the archaic East Asian peoples migrated into the far northeast of Asia where they evolved into the Arctic Peoples. These peoples evolved into a separate race because they were geographically isolated from the East Asians on he south by the high Chersky, Khrebet, Khingan, and Sayan mountains, and about a thousand miles of forest north of the Amur river. The Arctic Peoples experienced the severest winter conditions of all the races with coldest winter temperatures of about -15 degrees celsius and falling to about -20 degrees celsius during the main Würm glaciation. In response to these cold winters the Arctic Peoples evolved more pronounced form of the morphological cold adaptations of the East Asians, consisting of the flattened nose, the short legs and thick trunk, the subcutaneous layer of fat that gives the skin a yellowish appearance, and the epicanthic eye-fold. These severe winters would be expected to have acted as a strong selection for increased intelligence, but this evidently failed to occur because their IQ is only 91.
The explanation for this must lie in the small numbers of the Arctic Peoples whose population at the end of the twentieth century was only approximately 56 000 as compared with approximately 1.4 billion East Asians. While it is impossible to make precise estimates of population sizes during the main Würm glaciation, there can be no doubt that the East Asians were many times more numerous than the Arctic Peoples. The effect of the difference in population size will have been that mutations for higher intelligence occurred and spread in the East Asians that never appeared in the Arctic Peoples. The East Asians consisting of the Chinese, Koreans, and Japanese would have formed a single extended breeding population of demes in which mutant alleles for higher intelligence would have spread but would not have been transmitted to the Arctic Peoples isolated by high mountain ranges and long distance. The Arctic Peoples did, however, evolve a larger brain size, approximately the same as that of the East Asians, so it is curious that they do not have the same intelligence. A possible explanation for this is that the Arctic Peoples have evolved strong visual memory that would have been needed to remember landmarks in order to get home in largely featureless environments of snow and ice. An increase of this ability would have required an increase in brain size but is not measured in intelligence tests. A further pssibility is that one or more new mutant alleles for more efficient neurophysiological processes underlying intelligence may have appeared in the East Asians but not in the Arctic Peoples.

There is further anomaly in the intelligence of the peoples of Northeast Asia conerning the IQs of the Mongols of Mongolia and the closely related Samoyeds of Northern Siberia. There are no studies of the intelligence of these peoples but their low level of cultural development and technology suggests that it is not so high as that of the East Asians of China, Japan, and Korea. Yet these peoples also experienced many thousands of years of severe winter environments that have produced the pronounced morphological cold adaptations of the epicanthic eye-fold, short legs, and thick trunk that evolved in the Arctic Peoples. The probable explanation of this anomaly is the small population size of these peoples (the population of present-day Mongolia is approximately 2.4 million and there are only a few tens of thousands of Samoyeds of Northern Siberia) and they have been isolated from neighboring peoples by the Gobi desert and high mountain ranges, so new mutations for higher intelligence did not occur and their geographical isolation would have prevented the acquisition of these mutations from other races."

Summary

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nätdeutsch
Sunday, January 7th, 2007, 04:53 PM
the chart comparing east asian, "hybrid", european and african brain sizes has to be wrong.

there is no way that the average is in the upper 1,100s

SubGnostic
Sunday, January 28th, 2007, 10:50 PM
the chart comparing east asian, "hybrid", european and african brain sizes has to be wrong.

there is no way that the average is in the upper 1,100sTrue, it's quite questionable as even the average brain size of Africans is near 1300cc.


the chart comparing east asian, "hybrid", european and african brain sizes has to be wrong.

there is no way that the average is in the upper 1,100sThe reason for this is that the measured subjects were infants.

fog
Wednesday, March 14th, 2007, 04:11 AM
Often, the relation of head shape with brain size is discussed. Here I ask, do cranial dimensions correlate with the relative sizes of the different regions of the brain. By regions, I mean the regions of the brain with differing tasks or functions.

For example, consider a wide, short skulled mongoloid man and a long, narrow skulled Mediterraneanid man, with brains of equal total volume. Does the long protruding occipit of the Mediterraneaid result in whichever region of his brain borders the occiput being larger?

Will the region of the brain bordering the forehead be relatively smaller in men with sloping forehead?

Ultimately, do such differences result in differences in thought processes?

Dr. Solar Wolff
Wednesday, March 14th, 2007, 04:41 AM
Recently, in a TV program on Neanderthals a brain expert compared endocranial casts of a Neanderthal to a modern man. It must be noted that their skull shapes were somewhat different. Nevertheless, as the brain expert pointed out, the shape of the brain was essentially the same. This expert concluded that Neanderthals would have been just as smart and sapiens people. He also concluded that Neanderthal brain was 20% larger, a huge figure, so perhaps he was just being kind to sapiens.

Kurtz
Friday, August 3rd, 2007, 12:14 AM
A very interesting scientific text on this this misty topic, by an English doctor.


ABSTRACT: Why do modern humans have larger brains than earlier
people such as Homo erectus? As large brains cause problems in
childbirth, infancy and locomotion, the advantage they offer must
be substantial. This advantage might be associated with increased
IQ, but there is a problem: evidence from MRI volumetric surveys,
microcephaly and hemispherectomy shows that there exist individuals
with psychometrically normal IQ but Homo-erectus-sized brains. Why
did evolution increase brain size (with its associated costs) when
humans (as these individuals demonstrate) can have normal IQ
without bigger brains? I propose that the advantage may be related
to increased capacity for an aspect of intelligent behaviour not
measured by IQ tests but critical to the survival of our simple
hunter-gatherers ancestors: the capacity to develop expertise.

Whole text (ftp://ftp.princeton.edu/pub/harnad/Psycoloquy/1999.volume.10/psyc.99.10.002.brain-expertise.1.skoyles)

APFreimann
Tuesday, January 25th, 2011, 12:54 AM
While it is impossible to make precise estimates of population sizes during the main Würm glaciation, there can be no doubt that the East Asians were many times more numerous than the Arctic Peoples. The effect of the difference in population size will have been that mutations for higher intelligence occurred and spread in the East Asians that never appeared in the Arctic Peoples.91868 91869Tim Flannery in his 1994 book The Future Eaters: An Ecological History of the Australian Lands and People shows to me that there are many problems with the notion that intelligence will increase more in dense populations. In New Guinea’s Highlands, one has the densest rural populations in the world (1,600 people per square km) without any increase in the very low IQ value inherited from Aborigines.

This suggests that:

the higher east Asian population desnity cannot be the cause of higher IQ
that other more subtle factors must have helped raise East Asian IQ, of which I myself can suggest
wetter summers made creating fire more difficult during the autumn than in drier inland Asia
the very rich seas off East Asia meant that fishing (the most cognitively demanding way to subsist) became dominant and thus extreme intelligence and quick reactions were needed to catch fishThe islands of Japan and Sakhalin and the adjacent mainland were never rich in difficult-to-hunt large game when compared to inland Siberia where Arctic Peoples arose. More than that, the major large game species of Siberia - the reindeer - is not an aggressive and dangerous animal to hunt as can be shown by the fact that over long periods of time it was gradually domesticated, a result which requires the animal be relatively docile. The history of human use of reindeer suggests that perhaps animal domestication had precursors dating back well before its earliest records in 8,000 B.C. That is, people evolved relationships with animals ultimately domesticated long before domestication actually happened. If this be so, hunting would have placed fewer demands on intelligence than Lynn says, which would agree with the observed high IQs of Europeans and East Asians exposed to the extremely rich seas of the North Pacific and North Atlantic and able and/or required to depend on fishing. (Going back to Flannery, it would also agree with the fact that races with low IQ have no dependence on fishing even where reasonably productive seas exist and often place rigid taboos on the activity).