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Race differences in intelligence: A global perspective

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Source : Mankind Quarterly, Spring91, Vol. 31 Issue 3, p255, 42p
Author : Richard Lynn
Abstract : Presents a review of the world literature on racial differences in intelligence.
Studies using intelligence tests; Studies of reaction times; Contributions to civilization.
Race differences in intelligence: A global
perspective.
The world literature on racial differences in intelligence is reviewed from three points of
view. Firstly, studies using intelligence tests indicate that Caucasoids in North America,
Europe and Australasia generally obtain mean IQs of around 100. Mongoloids typically
obtain slightly higher means in the range of 100-106. African Negroids obtain mean IQs
of around 70, while Negroid-Caucasoids in the United States and Britain obtain means of
about 85. Amerindians and the South East Asian races typically obtain means in the
range of 85-95.
A second source of evidence comes from studies of reaction times which provide
measures of the neurological efficiency of the brain. These studies show that Mongoloids
have the fastest reaction times followed by Caucasoids and then by Negroids. Thirdly, the
races can be assessed for their contributions to civilization. Here the Caucasoids and the
Mongoloids have made the most significant advances both in the foundation of the early
civilizations and in more recent developments.
The existence of racial differences in intelligence has been known since the time of the
First World war when tests given to large numbers of military conscripts in the United
States revealed that blacks had an average intelligence level about 15 IQ points below
that of whites. In the following decades there has been debate over the question of
whether these differences have a genetic basis. This debate has largely taken place in the
context of the differences in intelligence found in different racial populations in the
United States. Genetic theorists have pointed to the high heritability of intelligence and
the difficulties of formulating credible environmentalist explanations to explain the
difference (Jensen 1972, 1973, 1980; Eysenck, 1971). Environmentalists have pointed to
a variety of factors which they consider capable of explaining the low Negroid IQ, of
which the most important are bias in the tests, the adverse social and economic living
conditions experienced by blacks, discrimination and prejudice from white majorities and
the historical legacy of slavery which has demoralized blacks and destroyed their family
structure (Flynn, 1980; Jaynes and Williams, 1989; Mackintosh and Mascie-Taylor,
1985). Neither side has yet succeeded in convincing the other and the issue remains
unresolved, although a recent poll has shown that the majority of experts now believe
there is some genetic basis to the low black IQ (Snyderman and Rothman, 1988).
The purpose of the present paper is to consider the problem of racial differences in
intelligence in a global perspective. Part one of the paper contains a review of the many
studies which have been made of the intelligence of different races throughout the world.
The principal question here is whether the world wide evidence supports the genetic or
the environmental position.
In general terms the genetic theory requires that there should be a reasonably high degree
of consistency of the intelligence levels shown by populations of different races in a
variety of geographical locations. Thus, Negroids should universally have lower
intelligence levels than Caucasoids and this difference should be found in Africa and the
West Indies as well as in the United States and Britain. The reason for this is that the
genes or alleles (alternative forms of genes) for low intelligence, if these exist, should be
present in all Negroid populations and not merely in those whose ancestors were
transported as slaves to the New World. Furthermore, Negroids in the United States and
Britain are nearly all Negroid-Caucasoid hybrids (Reed, 1969). Their Caucasoid genes
should, on the genetic hypothesis, raise their intelligence level as compared with the pure
Negroids of Africa. Hence the genetic theory demands that African Negroids should have
lower intelligence levels than the Negroid-Caucasoid hybrids of the United States and
Britain. Whether or not this is the case can be regarded as a test of the genetic theory and
any studies showing that pure African Negroids have higher IQs than American or British
Negroid hybrids would falsify the genetic hypothesis.
A similar degree of consistency of intelligence levels should be found for all races if the
intelligence is largely genetically determined. The intelligence of Caucasoids should be
approximately the same, whether they live in the United States, Britain, Europe, Australia
or New Zealand. The same consistency should be present in the third major race of
mankind, the Orientals or Mongoloids, who are present not only in their native habitat of
north east Asia but also in the United States and Europe. Hence a world wide
examination of the consistency of racial differences in intelligence would provide a
perspective on the genetic and environmental theories which is lacking in the studies
carried out in the local contexts of the United States and, more recently, in Britain.
Part two of the paper deals with the question of whether the racial differences in
intelligence as measured by intelligence tests are also present in reaction times, i.e. the
speed of response to simple stimuli. The interest of this question is that recent work has
shown that reaction times are a measure of intelligence and appear to represent
differences in the neurological efficiency of brain processes (Jensen, 1982; Eysenck,
1982). A positive finding of racial differences in reaction times would rule out many of
the explanations for the intelligence differences advanced by environmentalists such as
bias in the tests, the legacy of slavery and so forth, and would point to a genetically
determined neurological basis for the differences. Whether or not there are racial
differences in reaction times which run parallel with those in intelligence therefore
provides a further test of the genetic and environmental theories.
Part three of the paper considers the racial differences in the foundation and advancement
of civilization. The establishment of civilization required numerous discoveries such as
the invention of writing and arithmetic and these must have been due to the work of
highly intelligent individuals. This part of the paper considers whether the racial
differences in the establishment of civilizations are the same as those found in the
performance of intelligence tests.
Intelligence Test Performance
Intelligence tests were developed in the first two decades of the century and in the
following seventy years numerous studies have been published of the intelligence of
different peoples in many parts of the world. The principal studies have been collated and
classified by the race and are summarized in Tables 1 through 6.
Intelligence was initially conceptualized as a single entity quantified by the intelligence
quotient and many studies have reported racial differences in terms of a single IQ.
theoretical basis for representing intelligence in terms of a single IQ is Spearman's (1927)
work identifying a general factor present in all cognitive tests and his conceptualization
of this as general intelligence, now known as Spearman's g, and identified as a
generalized problem solving ability which enters into the performance of all cognitive
tasks.
This theory of intelligence was challenged in the nineteen thirties by Thurstone (1938)
who proposed an alternative model which dispensed with the concept of Spearman's g
and postulated six primary mental abilities designated reasoning, spatial, numerical,
verbal, perceptual speed and fluency abilities. In the late nineteen-forties an integration of
the Spearman and Thurstone models was proposed by Burt (1949). This consisted of a
hierarchical model of intelligence in which Spearman's general factor was split into two
correlated group factors now generally known as the verbal and visuospatial abilities.
These can in turn be broken down further into narrower primary abilities, of which some
twenty to thirty have been identified (Cattell, 1971). Burt's model is widely accepted in
contemporary psychology and is adopted in this paper. Where possible means for
different populations are given for general intelligence (Spearman's g) and for the verbal
and visuospatial abilities.
Intelligence tests are normally calibrated with the mean IQ set at 100 and the standard
deviation at 15. This metric has been adopted and the mean IQ of American Caucasoids
set at 100 to serve as the standard in terms of which IQs of all other populations are
expressed. Further details of the methods used of a single IQ. The for the calculations of
mean IQs for different populations are given in the appendix.
Caucasoids
Mean IQs for Caucasoid peoples in the United States, Britain, Continental Europe,
Australia and New Zealand are set out in Table 1. In this and in subsequent tables
summary results are given for the geographical location of the sample, the age of the
subjects, tile numbers, the tests used and mean IQs for general, verbal and visuospatial
intelligence. General intelligence is conceptualized as Spearman's g, the general factor
present in all cognitive tasks, and most effectively measured by tests of reasoning ability
such as Raven's Progressive Matrices and Cattell's Culture Fair Test. It can also be
measured by omnibus tests such as the Wechslers and the Stanford Binet. Results from
all these tests are entered in the tables under general intelligence. Verbal IQs in the tables
are derived from the verbal scales of the Wechslers and from verbal comprehension
scales in such tests as the Differential Aptitude and the McCarthy. Visuospatial IQs are
derived from the performance scales of the Wechslers and from visuospatial scales in the
Differential Aptitude, the McCarthy and similar tests, and from figure copying tests such
as the Draw-a-Man.
Inspection of the results set out in the table will show firstly that Caucasoids in the United
States and Britain obtain virtually identical mean IQs. This was first demonstrated in the
1932 Scottish survey of 11 years olds who obtained a mean IQ of 99 on the American
Stanford Binet. The subsequent studies shown in the table under Scotland and Britain
confirm this result. The earlier standardization of tests in the United States were generally
based on normative samples of Caucasoids only, such as the early Stanford Binet and
Wechsler tests, but the later standardizations such as the WISC-R included Negroids. For
this reason an adjustment has to be made to American means for later tests, because when
tile mean of the American total population is set at 100, the mean of American
Caucasoids is 102.25, as derived from the standardization sample of tile WISC-R (Jensen
and Reynolds, 1982).
Further inspection of the results set out in Table 1 shows that the mean IQs from all these
Caucasoid populations lies in the range of 94-107, with the single exception of a low
value of 87 for Spain found by Nieto Alegre et al (1967). The variations between and
within the countries are probably due principally to differences in sampling accuracy and
procedures and to differences in living standards. Differences in sampling accuracy and
procedures can occur because of the difficulty of obtaining representative samples and to
differences in whether the mentally retarded are included. In the case of children, those in
private schools may or may not be included in the samples. Sampling differences are
probably largely responsible for a number of the discrepancies in the means obtained
from the same country, e.g. the two studies of general intelligence in Australia give
means of 95 and 104, and the three studies of France give means of 98, 104 and 94.
The largest discrepancy in the table is between the mean IQ of 87 for Spain obtained by
Nieto Alegre et al and the mean of 98 obtained by Buj. This probably arises from a
sampling difference between the two studies. Nieto Alegre et al obtained their sample
from military conscripts drawn from the whole of Spain, whereas Buj drew his samples
for Spain and other countries from the populations of the capital cities. While the
sampling procedure adopted by Buj seems reasonable, it is probable that in less
economically developed countries like Spain with a rather backward peasant population
there are considerable differences between the mean IQs in the rural areas and in cities. In
fact in the Nieto Alegre study there was a range of approximately 15 IQ points between
the means of the conscripts from the poorest rural regions and the most prosperous and
more urbanized centers. As countries have become more industrialized the numbers of
their rural peasantry have declined and rural-urban differences in intelligence have
largely disappeared. Thus Scotland was a largely urbanized country by the 1930s and at
this time there was virtually no difference in mean IQ between urban and rural children
(Scottish Council for Research in Education, 1939).
In addition to differences in sampling, some of the differences between these Caucasoid
populations may also be ascribed to differences in living standards. There is a wide range
of these among this set of nations. For instance, in Spain which produced the lowest
mean IQ of 87 for military conscripts tested in 1965, the per capita income in that year
was 770 US dollars as compared with $2,003 in Britain and $4,058 in the United States
(United Nations, 1970). Low incomes have an adverse effect on intelligence because poor
people have less to spend on nutritious foods and tend to have less leisure to give their
children cognitive stimulation. Nevertheless, in spite of these considerable differences in
living standards, the overall picture of the results summarized in Table 1 is one of fairly
close similarity of mean IQs among these diverse Caucasoid populations.
The last entries in Table 1 are for the IQs of Indians derived from the Indian sub-
continent, South Africa and Britain. The mean of 86 in India is derived from a review by
Sinha (1968) of the results of 17 studies of children aged between 9 and 15 years and
totalling in excess of 5,000. Mean IQs lie in the range of 81 to 94, with an overall mean
of approximately 86. But ethic Indians in Britain obtain a mean of 96 which is within the
range of other Caucasoid populations. Their verbal IQ of 89 is depressed, but this is
probably because their families are recent immigrants and have not yet mastered the
language. The British results suggest that when Indians is are reared in an economically
developed environment their intelligence level is about tile same as that of European
Caucasoids.
Mongoloids
The Mongoloid peoples are those indigenous to north east Asia, north of the Himalayas
and east of the Yenisey river. Their mean IQs are set out in Table 2. It will be seen that
for general intelligence the Mongoloid peoples tend in the majority of studies to obtain
somewhat higher means than Caucasoids. This is the case in tile United States, Canada,
Europe, Japan, Hong Kong, Taiwan, Singapore and The People's Republic of China. The
range is from 97 to 110, with a mean of around 106. The lowest figure is the mean of 97
obtained by Stevenson et al for Japanese 6 year olds. One explanation for this result is
probably that Mongoloids tend to be late maturers. There is a good deal of evidence for
this reviewed in Lynn (1987). It will be noted that the same investigators obtained a mean
of 102 for Japanese 11 year olds. A further factor is that Stevenson obtained his
American comparison sample from the city of Minneapolis in Minnesota and the mean
Caucasoid IQ in Minnesota is 105 (Flynn, 1980, p. 107). This means that 5 IQ points
should be added to all of Stevenson's Japanese means.
There is some dispute about the mean IQs of ethnic Mongoloids in the United States.
Vernon (1982) reviewed the literature and concluded that the mean non-verbal IQ
(general intelligence) was around 110 and the verbal IQ 97. These figures have been
questioned by Flynn (1989) who maintains that the respective means are approximately
100 and 97. The best single study of American ethnic Mongoloids appears to be the
Coleman et al (1966) report of five age groups spanning the years 6-16 from which
Flynn's figures are derived. But there are problems with the Coleman study. One is that in
this and other studies the category of Orientals may include Filipinos, whose mean IQ is
about 85 (Flynn, 1991) and who therefore pull down the mean of ethnic Chinese end
Japanese. Filipinos constitute about 20 per cent of American Orientals and if these are
taken out of the Coleman sample the remainder who are largely ethnic Chinese and
Japanese obtain a mean non-verbal IQ of 103 and a mean verbal IQ of 98.
A further problem in the Coleman data concerns the nature of the tests of "non verbal
ability". Coleman himself is careful to state that the non verbal tests used in his study
were not measures of intelligence. The tests were of math ability largely set out in verbal
format and this will have given the tests a verbal bias and handicapped Orientals
(Coleman 1990). Probably the Coleman non verbal ability tests should not be considered
as good measures of general intelligence or Spearman's g. The weaknesses of the
American studies of ethnic Orientals is that hardly any of them provide a good measure
of visuospatial abilities or of Spearman's g.
If Flynn should prove to be correct it would appear that the mean IQ of American ethnic
Orientals is a little below that of Mongoloids in the countries of the Pacific rim. The
explanation for this may be that the early Chinese and Japanese immigrants from whom
the majority of ethnic Orientals are derived may have been below the average intelligence
levels of their parent populations in Asia. The early immigrants came largely as laborers
to build the railways and do other unskilled work developing the infrastructure of the
west coast. This not particularly desirable work may have attracted those of less than
average ability. If this is so, the high educational and occupational achievements of ethnic
Orientals in the United States may be due to high work motivation rather than high
intelligence levels.
A striking feature of the results for Mongoloids is that their verbal IQs are consistently
lower than their visuospatial IQs. In most studies the differences are substantial
amounting to between 10 to 15 IQ points. This pattern is present in Japan, Hong Kong,
the United States and Canada. It has also been found among ethnic Japanese in Hawaii
although these data are not presented in a form from which mean IQs can be calculated
(Nagoshi and Johnson, 1987).
This difference is also picked up in the United States in performance on the Scholastic
Aptitude Test (SAT), on which ethnic Orientals invariably do better than Caucasians on
the mathematics test (largely a measure of general intelligence and visuospatial ability)
but less well than Caucasians on the verbal test (Weiner, 1988). A further manifestation
of the strong visuospatial and weak verbal abilities of ethnic Oriental Americans lies in
their tendency to do well in professions like science, architecture and engineering which
call for strong visuospatial abilities and poorly in law which calls for strong verbal
abilities. This pattern of occupational achievement has been well documented by Weyl
(1969,1989) in his studies of the achievements of the major American ethnic populations.
His method involves the analysis of the frequencies of ethnic names among those who
have achieved occupational distinction calculated in relation to their frequencies in the
general population. Thus he finds that common Chinese names like Wong are greatly
overrepresented in American Men and Women of Science, as compared with their
frequency in the general population, but under represented in Who's Who in American
Law. On the basis of this method he constructs a performance co-efficient for which
average achievement is 100. A co-efficient of 200 means that an ethnic group appears
twice as frequently in reference works of occupational distinction as would be expected
from its numbers in the total population, while a co-efficient of 50 means that it appears
half as often. In his first study he finds that ethnic Chinese obtained performance co-
efficients of 506 in architecture, 303 in engineering and 438 in science but only 54 in law
(Weyl, 1969). His second study on later data confirms this pattern for the 1980s, when
ethnic Chinese obtained a performance co-efficient for science of 620, while for law their
performance co-efficient was only 24.
It is easy to understand how this remarkable disparity arises. Adolescents typically
discover that they tend to be good at some things and poor at others. There is a natural
tendency for young people to concentrate on those activities they are good at, be they
sciences, languages, arts, music, sport or whatever, and to make their careers in them.
The reason that different people are good at different things depends partly on genetic
and partly on environmental differences. The widespread appearance of the strong
visuospatial -- weak verbal ability pattern among Mongoloids in so many diverse
geographical locations suggests that it has a genetic basis and that this is responsible for
their striking over-achievement in the sciences and architecture and under-achievement in
law.
Negroids
The mean IQs of Negroids have invariably been found to be substantially lower than
those of Caucasoids. Many studies have been done in the United States and by the mid-
1960's Shuey (1966) was able to present a summary of 362 investigations. The overall
mean IQ of American Negroids was approximately X5. Subsequent studies in the United
States such as those of Coleman (1966), Broman, Nichols and Kennedy (1975) and others
have confirmed that this is about the right figure.
As a result of these studies it is sometimes assumed that the mean IQ of all Negroids is
approximately 85 or 1 standard deviation below that of Caucasoids. However, it has to be
noted that almost all American Negroids are Negroid-Caucasoid hybrids (Reed, 1989)
and the same is probably true of most Negroids in the West Indies and Britain. To obtain
mean IQs of pure Negroids it is necessary to take samples in Africa. For this reason mean
IQs for pure African Negroids are listed separately in Table 3 from Negroid-Caucasoid
hybrids in the United States, Britain, the West Indies and South Africa.
The first good study of the intelligence of pure African Negroids was carried out in South
Africa by Fick (1929). He used the American Army Beta Test, a non verbal test devised
in the United States in the First World War for testing recruits who could not speak
English, and administered it to 10-14 year old Caucasoid, Negroid and Colored (Negroid-
Caucasoid hybrids) school children. In relation to the Caucasoid mean of 100, based on
more than 10,000 children, largely urban pure Negroid children obtained a mean IQ of
65, while urban Colored children obtained a mean IQ of 84. It is interesting to note that
these South African Coloreds or Negroid-Caucasoid hybrids obtained a mean IQ virtually
identical to that of American Caucasoid-Negroid hybrids.
The other studies of the IQs of pure Negroids summarized in Table 3 show means in the
range 65-81. Vernon tested his small sample in Kampala with a number of tests and the
overall mean was about 80, but this sample was drawn from an academic secondary
school and the result suggests that the mean for the population would be around 70. The
best single study of the Negroid intelligence is probably that of Owen (1989), who
presents results for 1093 16 year olds in the eighth grade who had been in school for
around 8 years and should have been well versed in paper and pencil tests. The test used
was the South African Junior Aptitude which is well constructed and standardized and
provides measures of verbal and non verbal reasoning, spatial ability, verbal
comprehension, perceptual speed and memory. The mean IQ of the sample in comparison
with Caucasoid South African norms is 69. It is also around the median of the studies
listed in Table 3. It is proposed therefore to round this figure up to 70 and take this as the
approximate mean for pure Negroids.
Negroid-Caucasoid Hybrids
As noted, virtually all American Negroids are hybrids with some Caucasoid ancestry. The
same is probably the case with West Indian and British Negroids. Although this has never
been documented, West Indian Negroids lived as slaves on white owned plantations from
the 17th to the 19th century in similar conditions to those of Negroids in the United
States. There was undoubtedly a certain amount of interbreeding between white estate
owners and Negroid slaves, which gave rise to a number of Negroid-Caucasoid hybrids
whose existence as a considerable class was noted by Anthony Trollope in his Tour of the
West Indies.
The results for Negroid-Caucasoid hybrids are shown in Table 4. For the United States,
seven major post Shuey (1966) studies are listed because of their special interest by virtue
of the large number of subjects, because they yield IQs for the verbal and visuospatial
abilities, or because they are derived from young children. These show that the Negroid
mean IQ of approximately 85 is present among children as young as 2-6 year olds.
In Britain the three major studies of Negroids obtained mean IQs of 86, 94 and 87,
broadly similar to those in the United States. Figures are available for two of the
Caribbean islands, namely Barbados (mean IQ = 82) and Jamaica (mean IQ = 66-75).
The Negroid-Caucasoid differences appear to be of about the same magnitude for general
intelligence and the verbal and visuospatial abilities. Detailed studies by Jensen and his
colleagues have shown that when samples are carefully matched the Negroid-Caucasoid
differences are greatest for general intelligence (Spearman's g) and for the visuospatial
abilities and less for verbal ability (Jensen and Reynolds, 1982; Reynolds and Jensen,
1983; Naglieri and Jensen, 1987). Nevertheless, the broad picture, taking the results as a
whole, is that the three abilities are of approximately equal magnitude. This also appears
to be the case in South Africa according to the results of Owen.
Amerindians
The results of studies of the intelligence of Amerindians are summarized in Table 5. The
mean general IQs have invariably been found to be somewhat below that of Caucasoids.
The largest study is that of Coleman et al (1966) which obtained a mean of 94, but a
number of studies have reported means in the 70-90 range. The median of the 15 studies
listed is 89 which can be taken as a reasonable approximation, indicating that the
Amerindian mean IQ falls someway between that of Caucasoids and Negroid-Caucasoid
hybrids. The same intermediate position is occupied by Amerindians in performance on
the Scholastic Aptitude Test (Weiner, 1988).
In addition, all the studies of Amerindians have found that they have higher visuospatial
than verbal IQs. The studies listed are those where the Amerindians speak English as
their first language, so this pattern of results is unlikely to be solely due to the difficulty
of taking the verbal tests in an unfamiliar language. The verbal-visuospatial disparity is
also picked up in the Scholastic Aptitude Test, where Amerindians invariably score
higher on the mathematical test than on the verbal (Weiner, 1988).
The strong visuospatial-weak verbal pattern of abilities in the Amerindians resembles that
of the Mongoloids, although in the Mongoloids the whole ability profile is shifted
upwards by some 10-15 IQ points. This similarity is not altogether surprising in view of
the close genetic relationship of the two races, Amerindians being an offshoot of the
Mongoloids who crossed the Bering Straits from north east Siberia into Alaska at some
time in prehistory. The similarity of the cognitive profile of tile two races suggests that
this profile was present in the common stock from which both contemporary races at-e
derived, and that some factor raised the intelligence levels in the Mongoloids following
the geographical differentiation of the two races.
South East Asians
The South East Asian races comprise Polynesians, Micronesians, Melanesians, Maoris
and Australian Aborigins. The results of intelligence test studies of these subs-aces are
shown in Table 6. Apart from tile low mean of 67 tot a small sample of Australian
Aborigine children all the mean Iqs lie in the range of 80-95 The one study to include
measures of general, verbal and visuospatial abilities for New Zealand Maoris shows that
this group does not share the strong visuospatial-weak verbal ability profile of
Mongoloids and Amerindians Although the intelligence of this group of peoples has not
been extensively researched there are sufficient studies to suggest a mean IQ of about 90.
Racial Differences in Reaction Times
It has often been argued that the racial differences in intelligence test performance may
be due to the tests being biased or to a variety of environmental factors such as
differences in education experience of clearing with visual representations motivation,
attitudes towards test taking and nutrition. The alternative theory is that these differences
have a genetic basis. In order to test for which of these different explanations is correct, a
study has been carried out to determine whether the racial differences in intelligence are
also present in reaction times. The rationale of the study is that reaction times provide a
measure of the brains neurological efficiency in dealing with very simple tasks and ate
unaffected by education, motivation and other environmental factors with the possible
exception of extreme malnutrition.
It has been shown in a number of studies that reaction times are positively associated
with intelligence and the explanation widely accepted for this association is that reaction
times provide a measure of the neurological efficiency of the brain in analysis and
decision making (Jensen, 1982; Eysenck, 1982). Hence if there are racial differences in
reaction times of the same kind as those present in intelligence test performance, it can be
inferred that these differences lie at the neurological level and probably reflect genetic
differences.
Reaction times consist of the speed with which a subject reacts to simple stimuli.
Normally a light comes on and the subject has to press a button to turn it off. Reaction
time tasks can be varied to present different degrees of difficulty. In the present study
three reaction time tasks were used of different degrees of difficulty. In the simplest task
a single light comes on and the subject moves his hand to switch it off. This response
normally takes around half a second. In more complex situations, one of several lights
comes on and has to be switched off. These are known as choice reaction times and take a
little longer. In a still more complex task, three lights come on of which two are close
together and one stands apart. Here the subject has to judge which is the light that stands
apart and switch it off. This is known as the odd man out task. It is more difficult than the
simpler reaction time tasks and typically takes about twice as long.
All three reaction time tasks were used in the present study. In addition, the apparatus
used in the investigation was designed to measure two separate processes in reaction time
tasks known as movement times and decision times. In these tasks the subject has to
make a decision about what to do (decision times) and then execute the decision by
moving the finger to switch off the light (movement times). Both these times were
recorded automatically on disks by a microcomputer.
The subjects used in the study consisted of 9 year old children representative of the three
major races of Mongoloids, Caucasoids and Negroids. The Mongoloids were obtained
from Hong Kong and Japan, the Caucasoids from Britain and Ireland and the Negroids
from South Africa. All the children were drawn as socially representative samples from
typical public primary schools in their respective countries with the exception of the Irish
children who came from rural areas and whose mean IQ was rather lower than would
otherwise have been expected.
In all the five samples decision times, movement times and variabilities were negatively
correlated with intelligence. Further details of tile reaction time apparatus, testing
procedures and analyses of the relationship between tile reaction time measures and
intelligence for the samples are given in Shigehisa and Lynn (1991), Chan, Eysenck and
Lynn (1991) and Lynn and Holmshaw (1991).
Summary statistics for tile five samples giving the numbers tested, mean IQs, means for
tile 12 reaction time measures and standard deviations for tile entire sample are shown in
Table 7. The last column of the table gives product moment correlations between tile
Progressive Matrices and the 12 reaction time measures. It will be seen that the Hong
kong and Japanese children obtained tile highest mean IQs, fastest decision times and low
decision time variabilities, the British and Irish children were inter-mediate, while tile
South African Negroids obtained the lowest means on tile Progressive Matrices, slowest
decision times and highest variabilities. All tile correlations are high and five of tile six
are statistically significant.
The movement times of the five populations do not show any consistent overall
relationship with Progressive Matrices scores. It is however interesting to note that tile
Negroid children tend to have fast movement times. In the complex and odd man out
tasks their movement times are significantly faster than those of British Irish and Chinese
children.
It is known that tile speed of reaction times is genetically determined to a significant
extent. This has been shown by Vernon (1989) in a study of 50 identical and 52 non-
identical twins, which produced a heritability coefficient of .51 for reaction times.
somewhat similar results have been reported by Ho, Baker and Decker- (1988) for two
other speed of information processing tasks which gave heritability coefficients of .47
and .24. These authors have also shown that the positive correlation between treasures of
speed of information processing and intelligence arises from common genetic processes
suggesting that common genetically controlled neurological mechanisms are involved in
the performance of both types of task.
It is therefore considered that the most reasonable interpretation of the Mongoloid-
Caucasoid-Negroid results is that these reflect genetic differences between the three
racial groups. It is not considered likely that educational differences could be involved
because of the extreme simplicity of the tasks. Motivational differences are improbable,
because reaction times seem unaffected by motivation (Jensen, 1982). It might be thought
that nutritional differences might be involved.
However, the fact that the Negroid children performed faster than the Caucasoid on
movement times makes it unlikely that poor nutrition could have reduced neural
conduction rates. We are therefore left with genetically determined differences in
information processing capacities as the most probable explanation of the Mongoloid-
Caucasoid-Negroid differences in decision times.
Contributions to Civilization
A third source of evidence on racial differences in intelligence lies in the degree to which
the various races have made significant intellectual, scientific and technological
discoveries and inventions. The argument is that these advances are likely to be made by
a few outstanding and highly intelligent individuals. There will be more of these in a
population where the average level of intelligence is high, and hence the intelligence
levels of populations and whole races can be inferred from their intellectual
achievements.
The first writer to advance this argument was Galton (1869) but he limited his analysis to
the Greeks of the classical period, England and Scotland, the Negroids and the Australian
Aborigines. His conclusion was that the Greeks produced the greatest number of
intellectual advances and could therefore be considered the most intelligent population.
He placed the Scots marginally above the English, and a long way below these he placed
the Negroids and the Aborigines.
Galton's treatment of the problem was sketchy but it provided the initial idea on which
others were to build. The most extensive analysis of this kind was carried out by Baker (
1974). He first set: up twenty one criteria by which the achievements of early
civilizations could be judged. These were as follows:
1. In the ordinary circumstances of life in public places, they cover the greater part
of the trunk with clothes.
2. They keep the body clean and take care to dispose of its waste products.
3. They do not practice severe mutilation or deformation of the body, except for
medical reasons.
4. They have knowledge of building in brick or stone, if the necessary materials are
available in their territory.
5. Many of them live in towns or cities, which are linked by roads.
6. They cultivate food-plants.
7. They domesticate animals and use some of the larger ones for transport (or have
in the past so used them), if suitable species are available.
8. They have knowledge of the use of metals, if these are available.
9. They use wheels.
10. They exchange property by tile use of money.
11. They order their society by a system of laws, which are enforced in such a way
that they ordinarily go about their various concerns in times of peace without
danger of attack or arbitrary arrest.
12. They permit accused persons to defend themselves and to bring witnesses for their
defence.
13. They do not use torture to extract information or for punishment.
14. They do not practice cannibalism.
15. Their religious systems include ethical elements and are not purely or grossly
superstitious.
16. They use a script (not simply a succession of pictures) to communicate ideas.
17. There is some facility in the abstract use of numbers, without consideration of
actual objects (or in other words, at least a start has been made in mathematics).
18. A calendar is in use, accurate to within a few days in the year.
19. Arrangements are made for the instruction or the young in intellectual subjects.
20. There is some appreciation of the fine arts.
21. Knowledge and understanding are valued as ends in themselves.
Having set up these criteria, Baker proceeded to analyze the historical record of the races
to ascertain which have originated civilizations. His conclusion was that the Caucasoid
peoples developed all 21 components of civilization in four independent locations. These
were the Sumerian in the valley of the Tigris and the Euphrates, the Cretian, the Indus
Valley, and the ancient Egyptian. The Mongoloids also developed a full civilization in
the Sinic civilization in China. The Amerindians achieved about half of the 21
components in the Maya society of Guatemala, a little less in the Inca and Aztec
societies, but these peoples never invented a written script, the wheel (except possibly in
children's toys), the principle of the arch in their architecture, metal working, or money
for the exchange of goods. The Negroids and the Australian aborigines achieved virtually
none of the criteria of civilization.
While Baker confined his analysis to the achievements of the races in originating
civilizations, there can be little doubt that the same race differences appear in the
historically later development of more advanced cultures. During the last 2,000 years the
many discoveries that constitute developed peoples have been made only by the
Caucasoid and Mongoloid peoples. For the first sixteen hundred or so years of this period
a case can be made out that the Mongoloid civilization in China was marginally ahead.
The Han period of around 200-100 BC saw the introduction of written examinations for
candidates for the mandarin civil service, an idea which was considered an advance when
it was introduced into Britain some 2,000 years later (Bowman, 1989). Printing was
invented in China by about 800, some 600 years before it was developed in Germany.
When Marco Polo visited China about the year 1300 he was amazed at the quality of
civilization in the numerous prosperous cities and particularly at the use of paper money,
a concept not introduced into the general use in Europe until the nineteenth and twentieth
centuries. The Chinese discovered gunpowder about the year 1050 and developed the
technology for using it for guns and not only, as popularly supposed, for fireworks. They
were the first to invent the principle of the magnetic compass. Their technology for the
manufacture of high quality porcelain was well ahead of anything in Europe until the late
eighteenth century. Details of these and many other Chinese scientific and technological
achievements are given in Needham (1954).
During the last five centuries the Caucasoid peoples of Europe and latterly of North
America have pulled ahead of the Mongoloids in science and technology. This is
probably because China has been run as a single bureaucratic empire in which innovation
has been discouraged first under the emperors and more recently under the communists
while Japan was isolated from outside influences until relatively recently. Europe, in
contrast, has been divided into numerous states, many of which afforded a high degree of
personal freedom of thought, expression and technological innovation, and between
which there was open communication. Nevertheless, although the Europeans have
generally been ahead of the Mongoloids during the last five centuries, since 1950 the
Japanese have provided a strong challenge and have surpassed the West in the production
of a number of high quality technological goods.
A useful source for evaluating the contributions of the human races to scientific and
technological achievements is available in Asimov's (1989) Chronology of Science and
Discovery. This lists approximately 1,500 of the most important scientific and
technological discoveries and inventions which have ever been made. The first three are
bipedality the manufacture of stone tools and the use of fire which antedate the evolution
of the races. Thereafter every single invention and discovery was made by the Caucasian
or Mongoloid peoples. This compilation confirms the historical record. Who can doubt
that the Caucasoids and the Mongoloids are the only two races that have made any
significant contribution to civilization.
Conclusion
The studies of racial differences in intelligence test results reaction times and scientific
and technological discoveries show a high degree of consistency. All three sources of
evidence indicate that the two races with the highest intelligence levels are the
Mongoloids and the Caucasoids. These are followed by the Amerindians, while the south
east Asian races and the Negroids are ranked lowest. The intelligence test results and the
reaction times tend to indicate that average Mongoloid intelligence levels are a little
higher than those of Caucasoids, but the difference is relatively small as compared with
other racial differences.
The general consistency of the results from the three sources of evidence, and the
consistency of the different intellectual achievements of the races over a long historical
period, points to a substantial genetic determination for these differences. If genetic
factors were not involved, there would have been much greater variation over time and
place and the observed consistencies would not be present. Whatever criteria are adopted,
the Caucasoids and the Mongoloids are the two most intelligent races and the historical
record shows that this has been the case for approximately the last 5,000 years.
The environmentalist may argue that the Negroid peoples in Africa, the Caribbean, the
United States and Britain, and the Amerindians, Maoris and Australian aborigines, all
live in socially and economically impoverished conditions, as compared with Caucasoids
and Mongoloids, and that these conditions are responsible for some or perhaps all of their
low intelligence. This argument can be met by the concept of genotype-environment
correlation, originally proposed by Plomin, De Fries and Loehlin (1977) and developed
by Scarr and McCartney (1983).
There are two processes of genotype-environment correlation which are relevant to the
present problem. The first is "passive" and has the effect that children tend to be reared in
environments which are e cot related with their own genetic potentialities. The principle
applies for any trait which has a heritability, and this is undoubtably true of intelligence,
and in the case of intelligence means that intelligent parents transmit the characteristic
genetically through their genes and environmentally through tile advantageous
environment which they provide for their children The two modes of transmission have
the effect that intelligent children tend to be reared in intelligence-enhancing
environments. This brings the genotypes and the advantageous environments into
positive correlation and implies that those reared in advantageous environments tend to
have superior genotypes. This applies, for instance, to middle class children as compared
with working class children, and can also, arguably, be applied to Caucasoid and
Mongoloid children as contrasted with those of other races.
There is a second "active" type of genotype-environment correlation which states that
people play an active role in creating their own environments. Genotypically intelligent
peoples are able to create a socially and economically affluent environment to an extent
which cannot be done by less intelligent peoples. Scarr and McCartney call this "niche
building", and the two peoples who have been successful in building socially and
economically developed niches in which to live and rear their children have been the
Caucasoids and the Mongoloids.
The argument frequently advanced that poor social and economic conditions are
responsible for the lower intelligence of the Negroids, Aborigines and Amerindians
places tile cart before the horse. It assumes that the impoverished environments of these
peoples are simply the result of external circumstances over which these peoples
themselves have no control. Such a claim does not stand up to examination. There are so
many cases which it cannot explain, such as the achievements of Chinese, Japanese,
Korean and Vietnamese immigrants in the United States and of Indians in Britain and
Africa. The only plausible explanation for why these peoples have succeeded where
others, initially more advantageously placed, have failed is that they have the right
genotypes for building socially and economically prosperous environments for
themselves and their families.
Appendix: Notes on the Calculation of IQs
One of the principal problems in the calculation of the mean IQs for the various racial
populations concerns the date at which the data were collected. Mean IQs in the
economically advanced nations have been increasing during the last half century (Lynn
and Hampson, 1986; Flynn, 1987). This poses the problem of whether an adjustment
should be made for this increase in studies where a test standardized in the United States,
Britain, Australia or New Zealand has been administered some years later to another
population. The adjustment involves making an addition to the American, British or
Australasian means to allow for the time interval between the two test administrations.
The effect is generally to increase Caucasoid IQs in relation to those of other peoples.
The increases are however quite small and do not remove the higher means obtained by
Mongoloid populations, as shown in Lynn (1987).
For the present paper it was decided not to make such adjustments on two grounds.
Firstly, the rates of secular increase of intelligence vary widely from about 1 to 6 IQ
points per decade in studies of different age groups and different tests. It is therefore
impossible to obtain any precise estimate of what adjustment would be appropriate for
many of the tests. Secondly, the great majority of the studies employ tests initially
standardized in the United States, Britain, Australia or New Zealand. These countries
have high standards of living in relation to other populations and therefore enjoy some
environmental advantage for the development of intelligence. This advantage is to some
degree counterbalanced by the earlier administration of the tests. The decision was
therefore made not to adjust the results for other populations for the time differential
between tile two test administrations but to report the mean IQs as originally published.
However, tests given to racial groups in the same country as the standardization samples
have been reduced to allow for tile secular increase in the mean IQ of the base
population. This correction applies to the Kline and Lee (1972) Canadian Chinese
sample, whose mean IQs are reduced by 7 IQ points to allow for the secular increase of
intelligence 1947-1970; and to the Belgian Korean sample whose IQs are reduced by 10
points to allow for a secular increase of intelligence in Belgium 19541983.
Figures for general intelligence are derived either from nonverbal reasoning tests such as
the Progressive Matrices and the Culture Fair, or from full scale Wechsler IQs. In some
studies only verbal and performance Wechsler IQs are reported and where this is tile case
these have been averaged to give an approximate figure for the full scale IQ. Where
means for Wechsler subtests are reported, tile verbal IQs are calculated from Vocabulary,
Information, Comprehension, Similarities and Arithmetic, and Visuospatial IQs from
Block Design, Object Assembly, Picture Arrangement, Picture Completion and Mazes.
The reason for this is that factor analysis has shown that these are tile best measures of
tile two abilities (Jensen and Reynolds, 1982). In the case of non-American
standardizations of tile Wechslers, IQs are calculated from the WISC tests by reading tile
means off tile standardization tables and converting to American IQs. Buj's IQs are given
in relation to a British mean of 100.
Table 1: Mean IQs of various Caucasoid populations
Caucasoids
Sample Age Number Test
United States - - -
Austria adults 187 Culture Fair
Australia 9-13 35,000 Otis
Australia 6 600 Coloured PM
Australia 8-12 400 WISC
Belgium adults 247 Culture Fair
Belgium 5-15 600 WISC
Belgium 10-16 920 Culture Fair
Britain 13-15 10,000 Differential
Aptitude
Britain adults 1,405 Culture Fair
Bulgaria adults 215 Culture Fair
Czechoslovakia adults 363 Culture Fair
Czechoslovakia 6 832 Coloured PM
Denmark 12 628 Progressive Matrices
Denmark adults 122 Culture Fair
Finland adults 120 Culture Fair
France adults 1,320 Culture Fair
France 6-9 618 Coloured PM
Germany, DR 7-11 454 Coloured PM
Germany FR 6 3,607 Coloured PM
Germany FR adults 1,572 Culture Fair
Caucasoids
Intelligence
Sample General Verbal Visuo-spatial
United States 100 100 100
Austria 101 - -
Australia 95
Australia 104
Australia - - 104
Belgium 98
Belgium - - 101
Belgium 104
Britain 101 102 102
Britain 100
Bulgaria 94
Czechoslovakia 98
Czechoslovakia 104
Denmark 100
Denmark 99
Finland 96
France 94
France 104
Germany, DR 100
Germany FR 102
Germany FR 107
Caucasoids
Sample Source
United States
Austria Buj. 1981
Australia McIntyre, 1938
Australia Reddington and Jackson, 1980
Australia Radcliffe and Trainer, 1969
Belgium Buj, 1981
Belgium Berte, 1961
Belgium Goosens, 1962
Britain Lynn, Hampson and Iwawaki, 1987
Britain Buj, 1981
Bulgaria Buj, 1981
Czechoslovakia Buj, 1981
Czechoslovakia Raven, 1986
Denmark Veileskov, 1968
Denmark Buj, 1981
Finland Buj, 1981
France Buj, 1981
France Bourdier, 1964
Germany, DR Kurth, 1969
Germany FR Schmidtke, Schaller & Becker, 1978
Germany FR Buj, 1981
Caucasoids
Sample Age Number Test
Greece adults 220 Culture Fair
Hungary adults 260 Culture Fair
Ireland adults 75 Culture Fair
Italy adults 1,380 Culture Fair
Italy 10-16 614 Progressive Matrices
Netherlands adults 333 Culture Fair
New Zealand 9-15 26,000 Otis
New Zealand 8-16 2,635 Progressive Matrices
Norway adults 100 Culture Fair
Poland adults 835 Culture Fair
Poland 10 213 WISC
Portugal adults 242 Culture Fair
Romania 6 300 Coloured PM
Scotland 11 1,000 Stanford Binet
Scotland 11 1,215 Terman Merrill
Spain 10 113,749 Progressive Matrices
Spain adults 848 Culture Fair
Sweden adults 205 Culture Fair
Sweden 6-15 1,106 WISC
Switzerland adults 163 Culture Fair
Yugoslavia adults 525 Culture Fair
India children 5,000 various
British Indians 11 170 British Ability
S.African Indians 16 1,063 Junior Aptitude
Caucasoids
Intelligence
Sample General Verbal Visuo-spatial
Greece 97
Hungary 99
Ireland 78
Italy 101
Italy 100
Netherlands 107
New Zealand 99
New Zealand 102
Norway 100
Poland 106
Poland 107
Portugal 101
Romania 95
Scotland 99
Scotland 102
Spain 87
Spain 98
Sweden 104
Sweden - - 104
Switzerland 101
Yugoslavia 104
India 86
British Indians 96 89
S.African Indians 85
Caucasoids
Intelligence
Sample Source
Greece Buj, 1981
Hungary Buj, 1981
Ireland Buj, 1981
Italy Buj, 1981
Italy Tesi and Young, 1962
Netherlands Buj, 1981
New Zealand Redmond and Davies, 1940
New Zealand Raven and Court, 1989
Norway Buj, 1981
Poland Buj, 1981
Poland Firkowska et al 1978
Portugal Buj, 1981
Romania Zahirnic et al 1974
Scotland Scottish Council, 1933
Scotland Scottish Council, 1949
Spain Nieto-Alegre et al 1967
Spain Buj, 1981
Sweden Buj, 1981
Sweden Scandinaviska Test for laget,
1970
Switzerland Buj, 1981
Yugoslavia Buj, 1981
India Sinha, 1986
British Indians Mackintosh and Mascie-Taylor,
1985
S.African Indians Owen, 1989
Table 2: Mean IQs of various Mongoloid populations
Mongoloids
Sample Age Number Test
Japan 5-16 1,070 WISC
Japan 6 240 Vocabulary-spatial
Japan 11 240 Vocabulary-spatial
Japan 2-8 550 McCarthy Scales
Japan 4-6 600 WPPSI
Japan 6-16 1,100 WISC-R
Japan 13-15 178 Differential Aptitude
Japan 13-14 216 Kyoto-NX
Japan 3-9 347 Columbia MMS
Japan 9 444 Progressive Matrices
Hong Kong 6-15 4,500 Progressive Matrices
Hong Kong 10 197 PM, Space Relations,
Fluency
Hong Kong 9 376 Cattell Culture Fair
Hong Kong 6 4,858 Coloured PM
Mongoloids
Intelligence
Sample General Verbal Visuo-spatial
Japan - - 103
Japan 97 89 105
Japan 102 98 107
Japan 100 92 108
Japan 103 98 108
Japan 103 101 107
Japan 104 - 114
Japan 101 100 103
Japan 110 - -
Japan 110 - -
Hong Kong 110 - -
Hong Kong 108 92 114
Hong Kong 113 - -
Hong Kong 116 -
Mongoloids
Sample Source
Japan Lynn, 1977 a
Japan Stevenson, Stigler, Lee, Lucker
Kitamura and Hsu, 1985
Japan " " " "
Japan Lynn and Hampson, 1986 a
Japan Lynn and Hampson, 1986 b
Japan Lynn and Hampson, 1986 c
Japan Lynn, Hampson and Iwawaki, 1987
Japan Lynn, Hampson and Bingham, 1987
Japan Misawa, Motegei, Fujita and Hattori, 1984
Japan Shigehisa and Lynn, 1991
Hong Kong Lynn, Pagliari and Chan, 1988
Hong Kong Lynn, Pagliari and Chan, 1988
Hong Kong Lynn, Hampson and Lee, 1988
Hong Kong Chan and Lynn, 1989
Mongoloids
Sample Age Number Test
P R China 6-16 5,108 Progressive Matrices
Taiwan 16 1,290 Culture Fair
Singapore 13 147 Progressive Matrices
Belgium-Koreans 6-14 19 WISC
United States 6-17 4,994 Various
United States 6-11 478 Various
United States 6-10 2,000 Figure copying
United States 6 80 Hunter Aptitude
United States 6-14 112 Various
Koreans
Canada-Calgary 15 122 Differential aptitude
Canada-Vancouver 6-8 38 WISC
Mongoloids
Intelligence
Sample General Verbal Visuo-spatial
P R China 101
Taiwan 105 - -
Singapore 110 - -
Belgium-Koreans 110 102 115
United States 100 97 -
United States 101 - -
United States 105
United States 106 97 106
United States 107
Koreans
Canada-Calgary 105 97 108
Canada-Vancouver 100 94 107
Mongoloids
Sample Source
P R China Lynn,1991
Taiwan Rodd, 1959
Singapore Lynn, 1977b
Belgium-Koreans Frydman and Lynn, 1989
United States Coleman et al, 1966; Flynn,
1991
United States Jensen and Inouye, 1980
United States Jensen, 1973
United States Lesser, Fifer and Clark,
1965
United States Winick, Meyer and Harris,
Koreans 1975
Canada-Calgary Vernon, 1982
Canada-Vancouver Kline and Lee, 1972
Table 3: Mean IQs of various Negroid populations
Negroids
Sample Age Number Test
Congo adults 320 Progressive Matrices
Ghana adults 225 Culture Fair
Nigeria 6-13 87 Colored Matrices, PMA
Nigeria adults Progressive Matrices
South Africa 8-16 1,220 Progressive Matrices
South Africa adults 703 Progressive Matrices
South Africa 10-14 293 Army Beta
South Africa 9 350 Progressive Matrices
South Africa 16 1,093 Junior Aptitude
Uganda 12 50 Various
Zambia adults 1,011 Progressive Matrices
Negroids
Intelligence
Sample General Verbal Visuo-spatial Source
Congo 65 Ombredane, Robaye
and Robaye, 1952
Ghana 80 Buj, 1981
Nigeria 75 - 81 Fahrmeier, 1975
Nigeria 86 Wober, 1969
South Africa 81 Notcutt, 1950
South Africa 75 Notcutt, 1950
South Africa 65 Fick, 1929
South Africa 67 Lynn and Holmshaw,
1991
South Africa 69 60 69 Owen, 1989
Uganda 80 Vernon, 1969
Zambia 75 Pons, 1974;
Crawford Nutt,
1976
Table 4: Mean IQs of various Negroid-- Caucasoid hybrid Populations
Negroid-Caucasoid Hybrids
Sample Age Number test
United States - - 362 Studies
United States 4 4,550 Stanford Binet
United States 2 46 Stanford Binet
United States 6-18 4115 Verbal and non-verbal
United States 6 111 WISC
United States 6-16 305 WISC-R
United States 7-14 642 PMA
United States 6-11 2,518 Various
S Africa coloureds 10-14 4,721 Army Beta
Barbados 9-15 108 WISC-R
Britain 11 113 NFER
Britain 10 125 British Ability Scales
Britain 8-12 205 NFER
Jamaica 10-11 50 various
Jamaica 11 1,730 Moray House
Jamaica 5-12 71 WISC
Intelligence
Sample General Verbal Visuo-spatial
United States 85
United States 87
United States 86
United States 84 89
United States 81 86 80
United States 84 87 88
United States 77 77 83
United States 84
S Africa coloureds 84
Barbados 82 84 84
Britain 86 87
Britain 94 92
Britain 87
Jamaica 75 82 90
Jamaica 72 72
Jamaica 66 74 64
Sample Source
United States Shuey, 1966
United States Broman, Nichols and Kennedy,1975
United States Montie and Fagan, 1988
United States Coleman et al, 1966
United States Miele, 1979
United States Jensen and Reynolds, 1982
United States Baughman and Dahistrom, 1968
United States Jensen and Inouye, 1980
S Africa coloureds Fick, 1929
Barbados Galler, Ramsey and Forde, 1986
Britain Mackintosh and Mascie-Taylor, 1985
Britain Mackintosh and Mascie-Taylor, 1985
Britain Scarr, Caparulo, Bernardo, Tower
and Caplan, 1983
Jamaica Vernon, 1969
Jamaica Manley, 1963; Vernon, 1969
Jamaica Hertzig, Birch, Richardson and Tizard,
1972
Table 5: Mean IQs of Amerindians Amerindians
Sample Age Number Test
United States 6-17 4,994 verbal & non-verbal
Navajo 5-8 44 WISC
Navajo 4-5 27 WPPSI
Navajo 6-7 26 WISC
Navajo 16-17 100 WAIS
Navajo - 44 WISC-R
Oneidas 7-14 82 WISC
Canadian Indians - 236 WISC-R
Ojibwa, Canada - 35 WISC-R
Ojibwa & Crees,
Canada 6-7 33 WISC
" 9-10 31 WISC
" 14-15 36 WISC
" 16-20 60 WAIS
Dakota Indians 6-16 200 WISC-R
Papago 6-16 240 WISC-R
Amerindians
Intelligence
Sample General Verbal Visuo-spatial
United States 94 89
Navajo 79 65 93
Navajo 75 64 91
Navajo 78 66 96
Navajo 89 84 95
Navajo 78 64 95
Oneidas 91 86 97
Canadian Indians 97 90 105
Ojibwa, Canada 97 91 104
Ojibwa & Crees,
Canada 86 70 101
" 90 81 100
" 89 78 101
" 87 91 103
Dakota Indians 95 86 102
Papago 86 75 96
Amerindians
Sample Source
United States Coleman et al, 1966
Navajo Thurber, 1976
Navajo Cundick, 1970
Navajo Cundick, 1970
Navajo Howell, Evans & Downing, 1958
Navajo Teeter, Moore & Peterson, 1982
Oneidas Turner & Penford, 1952
Canadian Indians Crawley in McShane & Plas, 1984
Ojibwa, Canada McShane & Plas, 1984
Ojibwa & Crees,
Canada St John, Krichev & Bauman, 1976
" " " "
" " " "
" " " "
Dakota Indians Browne, 1984
Papago Reschly & Jipson, 1976
Table 6: Mean IQs of various south East Asian populations
South East Asians
Sample Age Number Test
Australia -- Peabody Picture
Aborigines 5-13 83 Vocabulary
Australia -- Peabody Picture
Aborigines 3-4 22 Vocabulary
Australia --
Aborigines 9 1,000 Queensland
New Zealand -- Primary Mental
Maoris 13 131 Abilities
New Zealand -- Progressive
Maoris 8 151 Achievement/PM
New Zealand --
Maoris 8-14 303 Queensland
New Zealand -- Progressive
Polynesians 8-9 71 Achievement
Carolines
Micronesians 12-18 400 Culture Fair
Singapore --
Malays 14 190 Progressive Matrices
Intelligence
Sample General Verbal Visuo-spatial
Australia --
Aborigines -- 80 --
Australia --
Aborigines -- 67
Australia --
Aborigines 85 -- --
New Zealand --
Maoris 93 95 87
New Zealand --
Maoris 92 91 --
New Zealand --
Maoris 90
New Zealand --
Polynesians -- 87
Carolines
Micronesians 88
Singapore --
Malays 96
Sample Source
Australia --
Aborigines Bruce, Hengeveld & Radford, 1971
Australia --
Aborigines Nurcombe and Moffit, 1970
Australia --
Aborigines McElwain and Kearney, 1973
New Zealand --
Maoris Walters, 1958
New Zealand --
Maoris Harker, 1978
New Zealand --
Maoris St George, 1983
New Zealand --
Polynesians Beck and St George, 1983
Carolines
Micronesians Jordheim and Olsen, 1963
Singapore --
Malays Lynn, 1977b
Table 7 Means for Progressive Matrices and 12 reaction time measures for
9 year old children from five countries (in milliseconds).
Hong Kong Japan Britain
Number 118 444 239
Progressive Matrices IQ 113 110 100
Decision time
simple 361 348 371
complex 423 433 480
omo 787 818 898
Movement time
simple 273 218 236
complex 267 227 261
omo 323 268 297
Decision time variabilities
simple 99 103 90
complex 114 138 110
omo 269 298 285
Movement time variabilities
simple 68 63 52
complex 65 66 56
omo 136 127 110
Ireland South Africa SD r
Number
Progressive Matrices IQ 317 350
Decision time 89 67
simple 388 400 64 -94[**]
complex 485 501 67 -89[*]
omo 902 991 187 -96[**]
Movement time
simple 260 236 72 13
complex 280 236 66 13
omo 307 256 96 56
Decision time variabilities
simple 121 129 32 -83[*]
complex 141 155 30 -73
omo 328 332 95 -85[*]
Movement time variabilities
simple 73 69 30 -33
complex 80 70 25 -42
omo 129 119 49 40
One and two asterisks denote statistical significance at the 5
and 1 per cent level, respectively.
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By Richard Lynn, University of Ulster, Coleraine, Northern Ireland
... Most disputed is the validity of the low mean IQ scores reported for sub-Saharan Africans. Lynn's (1991) review of 11 studies found a mean IQ of 70. A subsequent review of over two dozen studies by Lynn and Vanhanen (2002) found an average IQ of 70 for West, Central, East, and Southern Africa. ...
... Reaction times and variabilities were measured by computer and hence were not subject to any human error in recording. For details, see Shigehisa and Lynn (1991) for Japan; Chan and Lynn (1989) for Hong Kong and Britain;Lynn (1991) for Ireland; and Lynn and Holmshaw (1990) for South Africa. ...
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... As it stands, CLASH would result in similar proposals for violence reduction. In contrast, "cold winter theories" have posited that ancestral environments produced distinct evolutionary pressures, affecting behavioral and cognitive traits (Lynn 1991). Planning, future orientation, reduced aggression and violence, conscientiousness, general intelligence, and related slow LH traits are clearly described as evolved responses, requisite for survival and reproduction in northerly latitudes (Lynn 1991;Rushton 1985a;Hertler 2015; see Woodley 2011 on why intelligence may not directly correlate with LH strategy). ...
... In contrast, "cold winter theories" have posited that ancestral environments produced distinct evolutionary pressures, affecting behavioral and cognitive traits (Lynn 1991). Planning, future orientation, reduced aggression and violence, conscientiousness, general intelligence, and related slow LH traits are clearly described as evolved responses, requisite for survival and reproduction in northerly latitudes (Lynn 1991;Rushton 1985a;Hertler 2015; see Woodley 2011 on why intelligence may not directly correlate with LH strategy). ...
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A total of 80 authors working in a variety of scientific disciplines commented on the theoretical model of CLimate, Aggression, and Self-control in Humans (CLASH). The commentaries cover a wide range of issues, including the logic and assumptions of CLASH, the evidence in support of CLASH, and other possible causes of aggression and violence (e.g., wealth, income inequality, political circumstances, historic circumstances, pathogen stress). Some commentaries also provide data relevant to CLASH. Here we clarify the logic and assumptions of CLASH and discusses its extensions and boundary conditions. We also offer suggestions for future research. Regardless of whether none, some, or all of CLASH is found to be true, we hope it will stimulate future research on the link between climate and human behavior. Climate is one of the most presing issues of our time.
... Scholars including Frazier (1949) and Yosso and Solorzano (2005) interrogated the history of sociological studies, arguing that the disciplinary history has been shaped by the idea of race-or specifically Blackness-as a social problem. This could be seen in deficitbased research focused on culture of poverty (Lewis, 1966) or intellectual gaps (Loehlin et al., 1975;Lynn, 1991;Pasamanick & Knobloch, 1955;Peoples et al., 1995;Witty & Jenkins, 1936) that attempted to explain the problem of Blackness. The mark of these histories can still be seen in modern studies, for example, that focus on the "race gap" in educational outcomes (Bali & Alvarez, 2004;Brown-Jeffy, 2009;Mangino, 2013). ...
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While the term gentrification in an American context often incorporates racial turnover, the role of race in gentrification remains undertheorized. Employing a critical race lens, this study explores the historical relationship between race and gentrification in academic studies. I conduct a systematic review and a discourse analysis of 331 empirical studies of gentrification from 1970–2019. Findings show that although studies frequently employ racial categories, they do so in imprecise ways, subsuming race under class. Race-based theory is rare; race is primarily used as a variable of measure to examine conflict-oriented outcomes, such as displacement. This creates oppositional and homogenizing racialized typologies of “poor minority incumbents” and “wealthy White newcomers,” which remain steady despite an increasingly complex urban landscape. I argue that this limits our ability to understand how race, class, and power operate in space and underscores the need for a more clearly defined role of race within gentrification that focuses on positionality and power in lieu of a groupist emphasis on antagonistic racial categorization.
... A particular incentive to conducting the study was Lynn's (1991) report that, while the average IQ (as assessed by General Intelligence Tests) of people living in Britain and the US is about 100, that of people living in North East Asia is around 105 and that of the peoples of Sub Saharan Africa around 70. In the light of such apparently large differences between different nations it seemed unfair to compare an individual residing in Pakistan with norms developed in Britain. ...
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27 chapters giving background to, psychometric properties of, and cross- cultural standardisations of the Progressive Matrices tests. There are important chapters on the use of Item Response Theory and the Measurement of Change and on the mis-uses of the concept of "intelligence". To facilitate retrieval many of the chapters are available as separate entries on Research Gate.
... The argument that natural selection could not have favoured a higher level of cognitive ability in some populations than in others on the grounds that 'more IQ is always better' is obviously mistaken, since it implies that all primate species should have the same average cognitive ability as humans. What the argument fails to recognise is that there are costs as well as benefits to investing extra physiological resources in larger, more-complex brains [121,122], and the difference between these costs and benefits may not be the same in all environments [123,124]. Indeed, the argument betrays an ignorance of basic evolutionary theory, according to which, natural selection favours whatever traits enhance reproductive success within an organism's current environment, regardless of whether those traits are considered 'valuable' by modern humans [125,126]. Hence even though higher cognitive ability may be considered equally 'valuable' in all modern environments, one cannot assume that it enhanced reproductive success to an equal extent in all pre-modern environments. ...
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There is a large amount of evidence that groups differ in average cognitive ability. The hereditarian hypothesis states that these differences are partly or substantially explained by genetics. Despite being a positive claim about the world, this hypothesis is frequently equated with racism, and scholars who defend it are frequently denounced as racists. Yet equating the hereditarian hypothesis with racism is a logical fallacy. The present article identifies ten common arguments for why the hereditarian hypothesis is racist and demonstrates that each one is fallacious. The article concludes that society will be better served if the hereditarian hypothesis is treated the same way as any other scientific claim—critically, but dispassionately.
... During the 1980s I collected more data on race differences in intelligence and also carried out some studies on race differences in reaction times. I published these in Lynn (1991a) [28]. This gave the IQ of Europeans as 100, except in the south where it declines to the mid-90s; 106 for Northeast Asians; 92 for New Zealand Maori; 86 for Native American Indians; 86 for South Asians represented by India; 70 for sub-Saharan Africans; and 79 for Australian Aborigines. ...
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... As stated by Fernandes and Woodley of Menie (this issue), however, the combination of proximal and distal predictors impact both productivity and human capital. This thus implies that individual and population differences in intelligence may be the result of other distal factors, such as climate and ecology (Lynn, 1991), and not only of ontogeny. Fernandes and Woodley of Menie (this issue) stressed that future research may need to specifically examine the directionality of the relation between intelligence and human capital. ...
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Transcending reviewed proximate theories, Van Lange et al.'s CLASH model attempts to ultimately explain the poleward declension of aggression and violence. Seasonal cold is causal, but, we contend, principally as an ecologically relevant evolutionary pressure. We further argue that futurity and restraint are life history variables, and that Life History Theory evolutionarily explains the biogeography of aggression and violence as strategic adaptation.
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The performance of minority examinees on the SAT is carefully monitored by the national educational media. Changes of 10 or 15 points over a five-year period are interpreted as having a significant and important relationship to the educational process. A crucial assumption underlying the validity of this inference is that the performance of an examinee is unrelated to that examinee's choosing to identify his or her ethnicity. In this article, it is shown that this assumption is false and that the potential errors introduced by it dwarf the changes being interpreted as real.
Chapter
If a child does badly at school, lagging behind other children in learning to read, being assigned to lower streams or classes, failing exams and finally leaving school at 16 with few if any educational qualifications, it may seem only natural to say that the child was not good at schoolwork, perhaps that he was not academically minded or was just not very bright. We may thus think that we have explained the child’s performance at school by reference to his ability or capacity (or lack thereof). And if it could further be shown that the child also obtained low scores on standard intelligence or IQ tests, it might seem that this explanation had been confirmed: science would have documented the fact that the child lacked the intellectual ability needed for success at school.
Chapter
Public Law 94-142 (Section 612[5] [C] of the Education of the Handicapped Act) mandated, for the first time, racially and culturally nondiscriminatory assessment procedures in the identification of “handicapped” children to be served by federally funded programs. Each state is to establish procedures to assure that testing and evaluation materials and procedures utilized for the purposes of evaluation and placement of handicapped children will be selected and administered so as not to be racially or culturally discriminatory. Such materials or procedures shall be provided and administered in the child’s native language or mode of communication, unless it clearly is not feasible to do so, and no single procedure shall be the sole criterion for determining an appropriate educational program for a child.