I graduated in psychology and took my Ph.D. at the
University of Cambridge and have worked as lecturer in psychology at
the University of Exeter, professor of psychology at the Economic
and Social Research Institute, Dublin, and at the University of
Most of my work has been on intelligence. My major
discoveries are that the Oriental peoples of East Asia have higher
average intelligence by about 5 IQs points than Europeans and
peoples of European origin in the United States and elsewhere; and
that men have a higher average IQ than women by about 5 IQs points.
I first published the high IQ of the Oriental peoples in 1977 in a
paper on the intelligence of the Japanese. In subsequent years the
high Oriental IQ has been confirmed in numerous studies of Oriental
peoples in Hong Kong, Taiwan, South Korea, China, Singapore and the
In 1983 I published a paper in
Nature showing that the IQ in Japan had increased
over the course of the previous half century, a phenomenon now known
as the Flynn Effect following the demonstration by Jim
Flynn of secular increases in intelligence in number of countries.
In 1989 I proposed that the increases in intelligence have been
caused by improvements in nutrition. I have also published several
papers showing that intelligence is associated with brain size and
My work on intelligence and brain size led me to
consider the problem that women have smaller brains than men even
when allowance is made for their smaller bodies. This implies that
men should have higher average IQs than women, but it has been
universally asserted that men and women have equal average IQs. In
1994 I proposed that the solution to this problem is that girls
mature faster than boys and this compensates for their lower IQs,
which only appear at the age of 16 onwards. Among adults men have
higher average IQs than women by about 4 IQ points. This advantage
consists largely of higher spatial abilities but is also present in
non-verbal reasoning. In two meta-analyses of sex differences on the
Progressive Matrices carried out with Paul Irwing (2004, 2005) we
showed that in the general population men have a higher IQs than
women by 5 IQ points, and in university students the advantage of
men is 4.6 IQ points.
In 1991 I extended my work on race differences in
intelligence to other races. I concluded that the average IQ of
blacks in sub-Saharan Africa is approximately 70. It has long been
known that the average IQ of blacks in the United States is
approximately 85. The explanation for the higher IQ of American
blacks is that they have about 25 per cent of Caucasian genes and a
The theory I have advanced to explain these race
differences in IQ is that when early humans migrated from Africa
into Eurasia they encountered the difficulty of survival during cold
winters. This problem was especially severe during the ice ages.
Plant foods were not available for much of the year and survival
required the hunting and dismembering of large animals for food and
the ability to make tools, weapons and clothing, to build shelters
and make fires. These problems required higher intelligence and
exerted selection pressure for enhanced intelligence, particularly
on the Orientals.
My book Dysgenics (Westport, CT:
Praeger, 1996) showed that the eugenicists were right in their
belief that modern populations have been deteriorating genetically
in respect of health, intelligence and the personality trait of
conscientiousness. This deterioration began in the second half of
the 19th century and has continued up to the present.
My book Eugenics (Westport, CT:
Praeger, 2001) considers what measures could be taken to rectify
this and discusses the genetic future of mankind. It is argued
that genetic improvement is likely to evolve spontaneously through
the technique of embryo selection in which women will use IVF to
grow a number of embryos, have them genetically assessed and will
select for implantation those with genetically desirable qualities.
It is also likely that some authoritarian states will use genetic
engineering to improve the genetic quality of their populations for
My book IQ and the Wealth
of Nations (co-author Tatu Vanhanen of the University of
Helsinki) (Westport, CT: Praeger, 2002) considers the problem of
national differences in wealth and economic growth. Economists and
other social scientists have been trying to solve the problem of why
some nations are so rich and others so poor since Adam Smith’s
The Wealth of Nations (1776). We argue that an
important but hitherto unrecognised factor is the IQs of the
populations. We give measures and estimates of average IQs in the
world’s 185 nations and show that national IQs are strongly related
to national incomes and rates of economic growth. The principal
reason for this is that nations whose populations have high IQs can
produce goods and services that command high values in international
markets. See below for more details of this argument and on
the IQs of every nation in the world.
My book published in 2006 is Race Differences
in Intelligence: An Evolutionary Analysis. Augusta, Georgia:
Washington Summit Books (PO Box 3514, Augusta, GA 30914)
ISBN 1-59368-020-1 pp. 318., US$37.95 HB), $20.95 (PB)
(plus $6 for overseas orders).
A review by
Prof.J.P.Rushton in Personality and Individual Differences
is given below.
Lynn’s book represents the culmination of more than
a quarter of a century’s work on race differences in intelligence.
It was in 1977 that he first ventured into this field – some would
say minefield – with the publication of two papers on the IQ in
Japan and Singapore. Both showed that the East Asians obtained
higher means than white Europeans in the United States and Britain.
These initial studies were criticised, but the present book lists 60
studies of the IQs of indigenous East Asians all of which confirm
the original claim.
Hitherto studies of race differences in
intelligence have been largely conducted and discussed in local
contexts. In the United Sates they have been largely concerned with
the IQs of whites, blacks, Hispanics, Asians and Native American
Indians. In Australia they have been concerned with the low IQ of
the Aborigines, and in New Zealand with the low IQ of the Maoris..
These differences have typically been explained by racism and
discrimination of Europeans against minorities the legacy of
slavery, although a number of writers have posited a significant
genetic factor (Jensen, 1998; Rushton and Jensen, 2005). Lynn’s book
differs in taking a global perspective and consists of a review more
than 500 studies published world wide from the beginning of the
twentieth century up to the present. He devotes a chapter to each of
ten races, differentiated by Cavalli-Sforza, Menozzi and Piazza
(1994) into “genetic clusters”, which he regards as a transparent
euphemism for races.
His conclusions are that the East Asians (Chinese,
Japanese and Koreans) have the highest mean IQ at 105. These are
followed by the Europeans (IQ 100). Some way below these are the
Inuit (Eskimos) (IQ 91), South East Asians (IQ 87), Native American
Indians (IQ 87), Pacific Islanders (IQ 85), South Asians and North
Africans (IQ 84). Well below these come the sub-Saharan
Africans (IQ 67) followed by the Australian Aborigines (IQ
62). The least intelligent races are the Bushmen of the Kalahari
desert together with the Pygmies of the Congo rain forests (IQ
After the ten chapters setting out the evidence for
each of the ten races there follows a chapter on the reliability and
validity of the measures. These show that the studies have high
reliability in the sense that different studies of racial IQs give
closely similar results. For instance, East Asians invariably obtain
high IQs, not only in their own native homelands but in Singapore,
Malaysia, Hawaii and North America. To establish the validity of the
racial IQs he shows that they have high correlations with
performance in the international studies of achievement in
mathematics and science. Racial IQs also have high correlations with
national economic development, providing a major contribution to the
problem of why the peoples of some nations are rich and others poor.
He argues further that the IQ differences between the races explain
the differences in achievement in making the Neolithic transition
from hunter-gathering to settled agriculture, the building of early
civilizations, and the development of mature civilizations during
the last two thousand years.
Lynn tackles the problem of the environmental and
genetic determinants of race differences in intelligence and
concludes that these contribute about equally to the phenotypic
differences. He argues that the consistency of racial IQs in many
different locations can only be explained by powerful genetic
factors. He works out the genetic contribution in most detail for
the sub-Saharan Africans. His argument is that sub-Saharan Africans
in the United States experience the same environment as whites, as
regards determinants of intelligence. He argues that they have as
good nutrition as whites, as shown by their having the same average
height in studies going back to World War 1, and they have
approximately the same education as whites. He presents evidence
that blacks in the southern states have very little white ancestry
and have an IQ of about 80, and that proposes that this can be
adopted as the genotypic IQ of blacks, i.e. the IQ that blacks
attain when they are reared in the same environment as whites. The
IQ of blacks in sub-Saharan Africa is a good deal lower at 67.
Hence, the adverse environment in sub-Saharan Africa, which he
regards as consisting principally of poor nutrition and health,
contributes about 13 IQ points to the low IQ in sub-Saharan Africa.
Lynn’s estimate is not too different from that advanced in 1969 by
Jensen to the effect that about two thirds of the low IQ of blacks
in the United States is attributable to genetic factors, and the
more recent estimate of Rushton and Jensen (2005) that the figure is
around 80 percent. Lynn has (unsurprisingly for those familiar with
his work) put a bit more weight on the genetic factor.
The last three chapters are concerned with the
book’s subtitle (An Evolutionary Analysis)
and discusses howrace differences in intelligence have evolved.
He begins by putting the problem in context by summarizing Jerison’s
(1973) classic study showing that during the course of evolution
species have evolved greater intelligence in order to survive in
more cognitively demanding environments. For instance, in one of the
most dramatic of these developments, early mammals evolved larger
brains and greater intelligence to survive in the nocturnal
environment, for which they needed to evolve larger auditory and
olfactory analysing centres in the brain.
The same principle, Lynn argues, explains the
evolution of race differences in intelligence in humans. He
elaborates the argument he has advanced over the last fifteen years
that the race differences in intelligence have evolved as
adaptations to colder environments as early humans migrated out of
Africa. In North Africa and South Asia, and even more in Europe and
Northeast Asia, these early humans encountered the problems of
having to survive during cold winters when there were no plant foods
and they had to hunt big game to survive. They also had to solve the
problems of keeping warm. These required greater intelligence than
was needed in tropical and semi-tropical equatorial Africa where
plant foods are plentiful throughout the year. He shows that race
differences in brain size and intelligence are both closely
associated with low winter temperatures in the regions they inhabit.
For instance, he gives a figure of 1282 cc for the average brain
size of sub-Saharan Africans, as compared with 1367 cc for Europeans
and 1416 cc for Orientals. His analysis relating
race differences in intelligence to exposure to low winter
temperatures has recently been independently corroborated by Templer
and Arikawa (2005).
From time to time Lynn notes anomalies in his
theory that require explanations. One of these is that the Europeans
have made most of the great intellectual advances and discoveries,
while the East Asians, despite having a higher IQ have made
relatively few (as extensively documented by Murray, 2003). Lynn
proposes the explanation for this may be that the East Asians are
more conformist that Europeans and this inhibits creative
achievement. He also notes one or two anomalies in his cold winter
theory of race differences in intelligence. The most striking of
these is that the Inuit have been exposed to the coldest winter
temperatures and have evolved large brains, the same average size as
that of the East Asians. Yet their IQ is only 91, and this is the IQ
obtained by those who attend the same schools as Europeans. To
explain this anomaly he proposed that two genetic processes must be
assumed to explain the evolution of race differences in
intelligence. The first of these is that differences in the
frequencies of the alleles for high and low intelligence have
evolved between races such that the alleles for high intelligence
are more common in the races with the higher IQs and less common in
the races with the lower IQs. The early humans that migrated out of
Africa and spread throughout the world would have carried all the
alleles for high and low intelligence with them, but those who
colonized Asia and Europe were exposed to the cognitively demanding
problems of survival during cold winters. Many of those carrying the
alleles for low intelligence would have been unable to survive
during the cold winters and the less intelligent individuals and
tribes would have died out, leaving as survivors the more
intelligent. This process would have reduced and possibly eliminated
the alleles for low intelligence, leaving a higher proportion of the
alleles for high intelligence. The more severe the winter
temperatures, the greater the selection pressure for the elimination
of low IQ individuals carrying low IQ alleles. This process explains
the broad association between coldest winter temperatures and IQs
and brain size.
He now suggests that there must have been a second
genetical process that several new alleles for high intelligence
must have appeared as mutations in some races but did not appear in
others, and once these had appeared they were never transmitted to
other races. These new mutant alleles for high intelligence would
have been most likely to appear in large populations because a
mutation is a chance genetic event and hence would have been more
likely to occur in races with large populations than in those with
small. The Inuit comprised only very small populations numbering
today around 55,000, so they would be unlikely have had mutations
for higher intelligence that have to be assumed in the East Asians
and Europeans. Once a new mutant allele for higher intelligence had
appeared in the East Asians and Europeans it would have conferred a
selection advantage and would have spread throughout the group of
around 50 to 80 individuals in which people lived during the
hunter-gatherer stage of human evolution. It would then have spread
fairly rapidly to adjacent groups because hunter-peoples typically
have alliances with neighboring groups with which they exchange
mating partners, and it is reasonable to assume that this custom was
present for many thousands of years during the evolution of the
races. These alliances of groups are known as demes, and a
new mutant allele for higher intelligence and which conferred a
selection advantage would have spread fairly rapidly through a deme.
From time to time matings would take place between demes and by this
means new mutant alleles for higher intelligence would spread from
one deme to another and eventually throughout an entire race.
However, this would take some considerable time,
and Lynn proposes that in 25,000 years, consisting of approximately
1,000 generations, an advantageous allele would be transmitted about
800 miles. Hence, an advantageous allele occurring as a mutant in
the region of, say, Beijing, 25,000 years ago would not yet have
spread outside China and would take another 50,000 years or so to
reach the Inuit peoples of far North East Asia and even longer to
cross the Bering Straits into Alaska. In addition, there are
geographical barriers of high mountains between the East Asians and
the Inuit that would have imposed a further impediment for the new
alleles for higher intelligence being transmitted from East Asia
northwards. He extends this explanation to the low IQs of the
Australian Aborigines and Bushmen. These have only been small
populations, so the chance of mutations of high IQ alleles in them
would have been low.
To the arguments presented by Jensen (1998) for a
substantial genetic determination of the difference in intelligence
between blacks and whites in the United States, Lynn adds a more
general one. He advances the general principle of evolutionary
biology that wherever subspecies, strains or races have evolved in
different environments they invariably develop differences in all
characteristics for which there is genetic variation as a result of
mutations occurring in some subspecies and of adaptations to
different environments, and asserts that intelligence cannot be an
exception. He concludes witheringly that “The position of
environmentalists that over the course of some 100,000 years peoples
separated by geographical barriers in different parts of the world
evolved into ten different races with pronounced genetic differences
in morphology, blood groups and the incidence of genetic diseases,
and yet have identical genotypes for intelligence, is so improbable
that those who advance it must either be totally ignorant of the
basic principles of evolutionary biology or else have a political
agenda to deny the importance of race. Or both “. So much for the
assertion of the American Psychological Association’s task force
under the chairmanship of Ulrich Neisser set up to produce a
consensus statement on what is known about intelligence that
concluded that there is no persuasive evidence for genetic race
differences (Neisser et al., 1998). With the publication of Lynn’s
book it will never again be possible to make this assertion and
retain any credibility.
Over the years Lynn has made a number of important
contributions to the field of intelligence. He has written the
standard works on the dysgenic processes that have been taking place
almost worldwide for the last century and on how these could be
addressed (Lynn, 1996, 2001). He has shown that the problem of why
some nations are rich and others poor is largely explained by the
intelligence of the populations (Lynn and Vanhanen, 2002). He has
overturned the century long consensus that there is no sex
difference in intelligence by showing that men have a higher average
IQ than women by approximately 5 IQ points (Lynn and Irwing, 2004).
But I would guess that the present book documenting global race
differences in intelligence and analysing how these have evolved
will come to be seen as his crowning achievement.
Cavalli-Sforza, L.L., Menozzi, P. and Piazza, A.
(1994) The History and Geography of Human
Genes. Princeton, NJ: Princeton University
Jensen, A .R. (1998) The g
Factor. Westport,CT: Praeger.
Jerison, H. (1973) Evolution of the brain and
intelligence. New York: Academic Press.
Lynn, R. (1996) Dysgenics: Genetic
Deterioration in Modern Populations Westport,CT:
Lynn, R. (2001) Eugenics: A
Reassessment. Westport, CT: Praeger.
Lynn, R. and Irwing, P. (2004) Sex differences on the
Progressive Matrices: a meta-analysis.
Intelligence, 32, 481-498.
Lynn, R. and Vanhanen, T. (2002) IQ and the
Wealth of Nations. Westport, CT: Praeger.
Murray, C. (2003) Human Accomplishment.
New York: Harper Collins.
Neisser, U.et al. (1996) Intelligence: knowns and
unknowns. American Psychologist, 51,
Rushton, J. P. and Jensen, A. R. (2004) Thirty years of
research on race differences in cognitive ability.
Psychology, Public Policy and Law, 11,
Templer, D.I. and Arikawa, H. (2005) Temperature, shin
color, per capita income and IQ: an international
perspective. Intelligence, (to
Sets out evidence for race differences in intelligence
worldwide. Concludes that the average IQs of the races are Orientals
105; Europeans, 100; South Asians, 90; Native American Indians, 90;
Australian Aborigines, 90; sub-Saharan Africans,