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Race Differences in Intelligence: An Evolutionary Analysis

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Richard Lynn, one of the leading researchers on intelligence and personality and the author of several major books on IQ and personality research, summarizes in this landmark work what one scholar has described as “the definitive study of race differences in intelligence.” Since 1977, Richard Lynn has blazed a pioneering trail of research on racial differences in IQ. In previous books and scientific articles, Lynn has explored dysgenic trends in intelligence, sex differences in IQ, psychopathic personality traits, and the dimensions of personality and national character. In this book, Lynn analyzes the results of over 500 published studies that span ten population groups—races and sub-races worldwide—in what is certain to be a path-breaking book for IQ experts and educated laypersons alike. This comprehensive review of worldwide racial differences of general intelligence explores the formation of races, meaning of intelligence, validity of race differences in IQ, environmental and genetic correlates of intelligence, the relationship between brain size and intelligence, the evolution of racial differences in intelligence, and the factor of racial hybrids. In a relentlessly methodical approach, Lynn expands upon an extensive array of research findings from the biomedical and social sciences, including the latest studies from the fields of behavior genetics, evolutionary psychology, and anthropology in reaching his thought-provoking conclusions. Extensively referenced, this exhaustive study of race and IQ is a milestone accomplishment and should serve as the yardstick by which future research is measured. The IQs of the races…can be explained as having arisen from the different environments in which they evolved, and in particular from the ice ages in the northern hemisphere exerting selection pressures for greater intelligence for survival during cold winters; and in addition from the appearance of mutations for higher intelligence appearing in the races with the larger populations and under the greatest cold stress. 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. 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. From Race Differences in Intelligence An Evolutionary Analysis Richard Lynn

338 pages, Hardcover

Published March 30, 2006

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About the author

Richard Lynn

47 books88 followers
British Professor Emeritus of Psychology, who is known for his views on racial and ethnic differences.

Lynn was educated at Cambridge University. He has worked as lecturer in psychology at the University of Exeter, and as professor of psychology at the Economic and Social Research Institute, Dublin, and at the University of Ulster at Coleraine.

Most of his books are about the differences of IQ between different etnicities.

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Profile Image for Friedrich Mencken.
98 reviews81 followers
July 24, 2013
A horrible book for people who are emotionally convinced that there are no genetic basis for racial differences in intelligence as ”the consistency of all the racial differences in so many different nations, in the development of early and later civilizations, and the high heritability of intelligence wherever it has been investigated, all need to be considered in terms of Popper`s (1995) theory of the logic of scientific explanations. This states that a scientific theory generates predictions that are subjected to empirical testing. A strong theory has few assumptions and generates a large number of predictions that are empirically verified. If the predictions are disconfirmed the theory is weakened and may even be destroyed, although a single disconfirmation can generally be explained or the theory can be modified to account for it. For the problem of race differences in intelligence, the theory that these have some genetic basis explains all the numerous phenomena set out in the points listed above, and there are no serious anomalies. The theory that the race differences in intelligence are to a significant extent genetically based fulfills Popper`s criteria for a strong theory. Those who assert that there is no evidence for a genetic basis of racial differences in intelligence betray a lack of understanding of the logic of scientific explanation.” P-192

For a more in-depth explanation of intelligence and mental testing as such I recommend “Straight Talk about Mental Tests” by Arthur R. Jensen. For more on biological differences see John R. Bakers book Race.
Profile Image for Karpur Shukla.
21 reviews26 followers
May 17, 2015
What Pauli called "not even wrong", Gould called "just-so stories", and Feynman called "cargo cult science". It's an excellent example of how using metrics with internally variable definitions allows you to conclude whatever the hell you want.
49 reviews30 followers
March 3, 2026
‘Race Differences in Intelligence’ is based around Lynn’s massive database of studies. Despite the ‘Evolutionary Analysis’ promised in the subtitle, the focus is on documenting differences not explaining them.

Purporting to be“the first fully comprehensive review… of the evidence on race differences in intelligence worldwide”, he includes many races not covered in previous reviews (p2)

Using both morphological criteria and genetic data from Cavalli-Sforza et al, Lynn identifies ten races. Each receive their own chapter, which reviews studies on:
1) IQ
2) Reaction times
3) Brain size

IQs are said to be corrected for the Flynn Effect (p5-6).

But, with different rates of economic development, the Flynn effect has occurred at different rates in different places, so correcting for the Flynn effect is not easy.

Lynn also estimates a race’s “genotypic IQ”. He defines the “genotypic IQ” of Africans as “the IQ that Africans would have if they were raised in the same environment as Europeans” (p69).

That low-IQ groups usually provide worse environments is irrelevant. Why Lynn chooses Europeans as his comparison group is unclear.

He also discusses the average IQs of biracial people, which tend to be intermediate between those of the parent races.

Reaction Time
Reaction times refer to the time taken to perform elementary cognitive tasks, which everyone get right, but where the speed with which they get there correlates with IQ.

People with faster reactions would have an advantage in sports that involve, say, reacting to the speed and trajectory of a ball. Yet blacks, with low IQs, are overrepresented among elite athletes.

Yet Lynn distinguishes “reaction time proper” (i.e. when your hand begins to move towards the correct button) from “movement time” (i.e. how long the hand takes to get there).

Whites react faster, he reports, but blacks move faster, which, he suggests, “may be a factor in the fast sprinting speed of Africans” (p58-9).

But Nisbett reports:
“Movement times are just as highly correlated with IQ as reaction times” (Intelligence and How to Get It: p222)
Brain Size
Brain size also correlates with IQ (Pietschnig et al 2015).

Yet sex differences in brain-size are greater than between races, at least before controlling for body-size, but IQ differences are minimal, and dwarves have smaller brains but larger brains relative to body-size, but usually normal IQs.

Between species, brain-size also correlates with intelligence (see Encephalization Quotient)—but, if you think a culture-fair IQ test is impossible, try designing a species-fair one!

Rather than intelligence differences, race differences in skull shape may reflect Bergmann’s Rule, whereby larger bodies evolve in colder climates so as to minimize the proportion of the body directly exposed to the elements.

But it is unlikely that increases in metabolically-expensive brain tissue would evolve solely for regulating heat-loss when the same result could be achieved by modifying only external head shape.

Yet, if differences in brain size did evolve for this reason, could differences in intelligence have emerged as a byproduct?

Europeans
Lynn first discusses white Europeans. IQ tests were normed against whites, so whites score on average 100.

Southeast Europeans score lower. For Lynn, this is because:
“Balkan peoples are a hybrid population or cline, comprising a genetic mix between the Europeans and South Asians in Turkey” (p18)
In the 2015 edition, Lynn says the same of IQs in Southern Europe.

Balkan countries have lower living-standards—but Lynn sees lower IQs as causing lower living standards just as much as lower living standards cause lower IQ.

Portugal
Lynn claims Portuguese IQs are lower. He cites just two studies, giving averages of 101 and 88, one of which is actually around the European average.

He proposes:
“Intelligence in Portugal has been depressed by the admixture of sub-Saharan Africans. Portugal was the only European country to import black slaves from the fifteenth century onwards” (p19)
Studies have indeed found higher frequency of sub-Saharan mitochondrial haplogroup L in Portugal than elsewhere in Europe.

Ireland
According to Lynn, IQ in Ireland is also lower. He attributes this to “selective migration”.
“There has been some tendency for the more intelligent to migrate, leaving less intelligent behind” (p19)
Lynn also invokes “selective migration” to explain differences in East Asian IQs. Yet, here, it was supposedly the less bright who moved (p136; p138; p169).

Migrants likely differ in average personality from those staying at home, but I see no reason they would differ in intelligence. When you are starving in a potato famine, you don't need to be that bright to see that moving abroad might be a good move.

Of course, income is related to IQ and affects both the economic incentive to migrate, and the ability to afford the cost of transport.

But, without real data on migration patterns, Lynn’s claims represent no more than a post-hoc rationalization for IQ differences that are otherwise anomalous.

In the 2015 edition, Lynn also suggests priestly celibacy reduced Irish IQs, as bright boys were drawn to the priesthood and hence excluded from procreation.

But IQ is inversely correlated with religosity, and there is no evidence of reduced IQ in other Catholic countries (e.g. France, Austria).

Blacks
The next chapter is titled “Africans”, but, for Lynn, this term excludes North Africans, Pygmies and Khoisan.

Lynn’s earlier estimate of the average African IQ at 70 provoked ridicule. Undeterred, he now gives a figure of 67.

Blacks resident in the West—except Israel—score higher.

Lynn attributes this to both better environments and racial admixture, since African-Americans and West Indians have some European ancestry.

But this fails to explain why recent African migrants in the US and UK (mostly unmixed) outperform African-Americans and West Indians both academically and economically.

Musicality
Lynn discusses one type of ability not covered in previous reviews—musical ability.

For Lynn, black American accomplishments in jazz and pop music represent a paradox, since musical ability correlates with IQ.

Lynn reviews psychometric tests of musical ability, including recognising pitch changes, remembering tunes, and identifying notes in a chord (p55).

Blacks generally score lower than whites. The only exception is for rhythmical ability, but, even here, they score only equal to whites (p56), though Amerindians score higher (p160).

For Lynn, this is, on reflection, unsurprising.
“The low musical abilities of Africans… are consistent with their generally poor achievements in classical music” (p57)
But why is classical music the sole measure of ability? Even if the ability needed to compose/perform classical music is greater than for pop music, musical intelligence surely facilitates both, and the financial rewards of the latter are greater.

Perhaps psychometric tests fail to capture some element of musical ability. One feature common to African-American music, from rap ‘freestyling’ to jazz, is improvisation. D'Souza speculates:
“Blacks have certain inherited abilities, such as improvisational decision making, that… explain why they predominate in… jazz, rap and basketball” (The End of Racism: p440-1; see also Sailer 1996)
Bushmen
Blacks are not the lowest-scoring race. This honour goes to their African neighbours, Bushmen.

Henry Harpending has been quoted as observing:
“All of us have the impression that Bushmen are really quick and clever and are quite different from their [Bantu] neighbours… There will soon be real data from the Namibian school system about the relative performance of Bushmen… and Bantu kids – or more likely, they will suppress it” (Race: The Reality of Human Differences: p227)
Lynn’s data consists of just three studies, none resembling a full IQ test. But, from this dataset, Lynn confidently ascribes to Bushmen an average IQ of just 52 (p74-6).

If his earlier estimate of African IQs provoked ridicule, his figure for Bushmen is unlikely to fare better. Lynn responds:
“An IQ of 54 represents the mental age of the average European 8-year-old, and the average European 8-year-old can read, write, and do arithmetic and would have no difficulty in learning and performing the activities of gathering foods and hunting carried out by the San Bushmen. An average 8-year-old can easily be taught to pick berries put them in a container and carry them home, collect ostrich eggs and use the shells for storing water and learn how to use a bow and arrow… Apes with mental abilities about the same as human 4-year-olds survive quite well as gatherers and occasional hunters and so did early hominids” (p76-7)
Lynn has a point. But I suspect he would not last long in the Kalahari Desert.

Pygmies
Oddly grouped with Bushmen as a single race are Pygmies. Here, Lynn’s data is even more limited—just one study, again well short of an IQ test. Also, the author did not quantify his results and reports only that Pygmies scored much lower than other groups tested—who did not include other Africans (p78)

Lynn also infers a low Pygmy IQ from their foraging lifestyle, claiming the ability to transition to agriculture is related to intelligence.

Lynn also points to the enslavement of Pygmies by Bantus.

But, while it may be a “general principle” that “more intelligent races typically… enslave the less intelligent” (p78), this is hardly a rigid rule. Arabs sometimes enslaved Europeans.

Unlike for other races, Lynn gives no figure for the average Pygmy IQ and no data on brain-size.

Aborigines
Australian Aborigines are another group rarely covered in previous reviews. Yet data from Australian schools are quite abundant, from which Lynn infers an average IQ of 62 (p104).

Lynn also discusses Piagetian measures of development, reporting that a large number of Aborigine adults never come to recognize that a substance, transferred to a new container, remains of the same quantity (p105-7).

But, when tested on recalling locations, one study found they score as high as, and another much higher than, Europeans. Two studies (one unpublished) report lower scores.

Lynn explains Aborigine spatial memory as an adaptation for navigation in deserts with few landmarks. Despite smaller brains, Aborigines’ right visual cortex, implicated in spatial ability, is larger than in Europeans (p108-9).

South Asians and North Africans
Another group rarely treated separately in earlier reviews are “North Africans and South Asians”, also including Middle Easterners.

Physical anthropologists often lumped these with Europeans as ‘Caucasians’, but Lynn cites Cavalli-Sforza et al as showing, “South Asians and North Africans form a distinctive genetic ‘cluster’” (p79).

Their average IQ in their homelands is just 84 (p80), with South Asians in the UK scoring 89 (p84)

Yet the earliest civilizations—Mesopotamia, Egypt and the Indus Valley—arose in these regions.

Also, Indians are considered a Model Minority in America/Britain, overrepresented in the professions.

Pakistanis/Bangladeshisin the West earn much less, and some studies, misreported by Lynn, report higher IQs for British-Indians than British-Pakistanis (Mackintosh 2007).

Are Muslim IQs depressed by the practice of cousin marriage, by pregnant women fasting during Ramadam, or an influx of black African genes during the Islamic slave trade?

Or were low-caste (and hence perhaps low IQ) Indians more likely to convert to Islam to escape caste discrimination?

Jews
Another overachieving group tracing part of their ancestry to this region are Jews.

Lynn claims British and US Jews average around 108 in IQ (p68) His data for Israel are not broken down by ethnicity, but Lynn infers average scores of 103 for Ashkenazim, 91 for Mizrahim and 86 for Arabs (p94)

His explanations for Ashkenazi intelligence are unpersuasive.

First, he observes that Jews interbred with host populations. Thus:
“Ashkenazim Jews in Europe will have absorbed a significant proportion of the genes for higher intelligence possessed by… Europeans” (p95)
But this cannot explain how Ashkenazim came to outscore Europeans themselves.

Second, Lynn argues:
“[Persecution] operated to increase the intelligence of Ashkenazim Jews in Europe and the United States” (p95)
But other persecuted groups—Roma, African-Americans—have low IQs.

Asians
Excepting Jews, East Asians have the highest IQs, averaging 105 (p121-48).

But this includes only Northeast Asians. Southeast Asians average much lower, around 90.

Causes
Lynn identifies malnutrition as the only major environmental influence on IQ.
“The effect of malnourishment on Africans in sub-Saharan Africa and the Caribbean probably explains about half of the low IQs, leaving the remaining half to genetic factors” (p185)
But it is unclear what is meant by “half of the low scores” since he identifies no comparison group.

He rejects malnutrition as an explanation for African-American IQs, noting there is no evidence of short stature in American blacks and nor have surveys have found a higher prevalence of undernourishment (p185).

Lynn cites his own study of black Americans to conclude,
“There is a statistically significant association between light skin and intelligence… dark-skinned blacks have an IQ of 85 and light-skinned blacks have an IQ of 92” (p190; Lynn 2002)
Yet fails to explain how he divided blacks into two discrete groups on a trait varying continuously.

Lynn omits studies that investigated the association between IQ and admixture using blood-groups, a better measure than skin tone, since the latter is affected by environmental factors (e.g. sun exposure), and could conceivably have an indirect psychological effect. These studies found no association between blood-group and IQ (Loehlin et al 1973; Scarr et al 1977).

Lynn mentions the Eyferth study (1961) to report, “The IQ of African-Europeans was 94 in relation to 100 for European women” (p63). But he does not mention that the IQs of children fathered by black Americans were almost identical to that of those fathered by white servicemen.

Evolutionary Analysis
In the last three chapters comes the “Evolutionary Analysis” promised in the subtitle. Lynn identifies climate as the main factor responsible for differences, with colder climates demanding higher intelligence, citing a study that found an association between latitude and both the number and complexity of tools used by foragers (Torrence 1983).

He also emphasizes dietary differences.
“Peoples in tropical and subtropical latitudes are largely gatherers, while peoples in temperate environments rely more on hunting, and peoples in arctic and sub-arctic environments rely almost exclusively on hunting and fishing… because plant foods are unavailable except for berries and nuts in the summer and autumn” (p227)
However, I remain unconvinced that the environments currently inhabited by the two lowest scoring races—the Kalahari Desert and Australian Outback—are cognitively undemanding.

Eskimos
Finally, the IQs of those Lynn terms “Artic Peoples” (i.e. Eskimos) are problematic for Lynn’s theory.

They evolved in the coldest environment of all and have the largest brains, but their IQs average only 91.

Lynn suggests that Eskimos were prevented from evolving higher intelligence by small and dispersed populations, which meant that mutations conveying higher IQs either never arose or never spread through the population (p153; p239-40; p221)

But this sounds like a post-hoc rationalization: if conditions were harsher in Eurasia than in Africa, then this also would presumably have meant smaller, more dispersed populations here too, but this did not prevent mutations for intelligence spreading among Eurasians.

Lynn explains large Eskimo brains as reflecting only high visual memory (p153; p240).

Yet Aborigines also have high visual memory, but only their right visual cortex is enlarged (p108-9).

Full (i.e. vastly overlong) review here.

References
Eyferth 1959 Eine Untersuchung der Neger-Mischlingskinder in Westdeutschland. Vita Humana, 2, 102–114.
Loehlin et al 1973 Blood group genes and n**ro-white ability differences. Behavior Genetics 3(3):263-270
Lynn 2002 Skin Color and Intelligence in African-Americans. Population & Environment 23:201-207
Mackintosh 2007 Review of Race differences in intelligence: An Evolutionary Hypothesis [sic], by Richard Lynn, Intelligence 35,(1): 94-96
Pietschnig et al (2015) Meta-analysis of associations between human brain volume and intelligence differences, Neuroscience & Biobehavioral Reviews 57:411-432
Sailer 1996 Great Black Hopes, National Review, August 12
Scarr et al 1977 Absence of a relationship between degree of white ancestry and intellectual skills within a black population. Human Genetics 39(1):69-86
Torrence 1983 Time budgeting and hunter-gatherer technology. In Hunter-Gatherer Economy in Prehistory: A European Perspective
14 reviews
March 18, 2020
Great book. The author calmly, slowly, tells the facts to us. Without emotions and shortcuts. Each statement is supported by references to research, these are not just words. Superb fuel for launching SJW into orbit of Uranus.
Profile Image for Graham Seibert.
498 reviews4 followers
March 17, 2026
Can we move the discussion to the moral sphere?

What Lynn has concluded is beyond dispute. On a logical plane the argument is won. There have been no statistical works to refute Lynn's work such as "IQ and the Wealth of Nations" or "The Bell Curve." There are ample critics of his motives and methods and the completeness of his analysis. Lynn would agree there is room for more work. The truth is, however, that there have been no serious statistical studies undertaken to refute his findings. While his critics claim that Lynn has painted an incomplete picture, none of them are bringing hard science to bear in an effort to find contradictory results.

People find it morally wrong to accept Lynn's argument. Lincoln's "All men are created equal" is our dogma. We have dropped Abe's qualifier "...under the law." It is taken as the most egregious form of racism even to raise the question that intelligences might be different. Scholarly minds work hard to forget that within our lifetimes it was well known in California that Chinese and Japanese kids were smarter than we white kids were, and ignore the accumulating evidence that nothing has changed since. Here follow two typical paragraphs, these from the introduction to "Measured Lies".

"For the past three decades American society has become increasingly addicted to blatant or unabashed utterance of the unutterable. It is now fashionable to say what one's parents would not have dared to say: perhaps the poor and aged should be terminated; women ought to be replaced with life-like replicas fashioned by Disneyland engineers; children cost more than they are worth; Blacks really are sub-human and dangerous after all; the Indians better stop bellyaching or they'll get their butts whipped again.

"It would be nice if one could merely ignore such utterances; and as Kincheloe and Steinberg argue in their Introduction to Measured Lies, it would be nice to be able to ignore Herrnstein and Murray's utterance. But to do so would be much too dangerous, for unutterables have a way of assuming a persuasiveness and realism that often undergird destructiveness of various sorts. So Measured Lies had to be written."

I too believe it is a moral question, but come to an opposite conclusion as to the moral course of action. Holding the conclusion that all races are equally capable, we have felt compelled to explain the vast difference in observed achievement in moral terms. Either:

a) Certain peoples are morally inferior, unwilling to work, avoid drugs, get married before having children, etc., or

b) White people are morally culpable for systematically frustrating the aspirations of blacks, Indians and others through subtle racism, disparagement, etc.

Either way, simultaneously holding the hypothesis that all peoples are equally capable, and observing the manifest differences in their situations, many social observers have felt compelled to assign blame. That has led us to adopt measures to remedy problems that may be overblown or not exist. An ongoing effort to eradicate supposed white racism. Efforts to encourage minority children to give up their self-destructive habits. Vast expenditures inspired by NCLB to arrive at equal school outcomes on the assumption that all children are equally capable of success, which at once frustrates many by asking more than they can achieve, and withholds from more capable students the level of preparation they will need in a competitive world economy.

The assumption of equality also precludes us from observing that the antisocial behavior of some members of society may make sense from within the constraints of their existence. We like to think that dealing drugs and mugging people is not a rational course of action for anybody. For a kid with an IQ of 70 and no marketable skills, however poor the odds, these could be among the most probable paths to success. The decisions he makes may be uncomfortably reasonable given his circumstance. Wouldn't the moral thing be to attempt to see him as he is an attempt to integrate him into society?

To me the argument in the sphere of biology is over. Lynn and company have won. We need to consider ways to legitimize the discussion of public policy options that take different peoples' different average abilities into consideration.

The statistical review Lynn provides is overwhelming: hundreds of studies covering tens of thousands of subjects by dozens of researchers over many decades. This has been his life's work. His evolutionary history borrows more heavily from others, chiefly Cavalli-Sforza, with some references to Coon, Diamond and others.

Human evolution isn't my forte, but I was struck by a few omissions. The first is war. I would expect warfare to exert a strong evolutionary pressure. A related question is whether or not, as Murray and Herrnstein proposed, cognitive stratification has increased since the introduction of agriculture and commerce. It would seem that civilization would bring more mating opportunities to the wealthy and powerful, and that sexual selection would play a more powerful role in communities of more individuals. Think of the Biblical record both of King David's wars and amours. Lynn chose likewise not to address the question of the strong selection for intelligence among Ashkenazim recently raised by BYU researchers. There is a follow-on book to be done.

I add later, see Nicholas Wade's "Before the Dawn" for a fascinating analysis of mankind's evolution over the past 50,000 years. It seems wholly consistent with Lynn's findings.

Revisiting this book after six years, I find Lynn's summary of the case for genetic differences (p189) to be succinct and valuable. I add it here for my own reference and a summary of Lynn's thought.

5. Genetic Determinants of Race Differences in Intelligence
While environmental factors undoubtedly contribute to the differences in intelligence between the races, there are a number of considerations that suggest that genetic factors are also involved. Ten of these are discussed in this section.

First, it is a principle of evolutionary biology that when sub-populations of a species become geographically isolated and occupy different environments, they become genetically differentiated and eventually diverge so much that they become different species. Thus, squirrels in North America have evolved gray fur while those in Europe have evolved red fur. From an original ancestral species, cats have evolved into lions, leopards, and cheetahs in Africa, tigers in Asia, and jaguars and pumas in the Americas. The general principle has been stated by Dawkins (1988, pp. 238-9), who writes that when two populations become isolated from one another "they become so unlike each other that, after a while, naturalists would see them as belonging to different races; after a longer time, they will have diverged so far that we should classify them as different species... the theory of speciation resulting from initial geographical separation has long been a cornerstone of mainstream, orthodox neo-Darwinism."

The processes by which these genetic divergences take place have been described in Chapter 2. It is in accordance with this principle that the races have become genetically differentiated for all characteristics for which there is genetic variation, including body shape; color of skin, hair, and eyes; prevalence of genetic diseases; and blood groups. It is inconceivable that intelligence would be the single exception to these differences. Some racial differences in intelligence must also have evolved as a matter of general biological principle.

Second, the studies summarized in Table 13.1 show a consistency of the IQs of the races in a wide range of geographical locations that can only be explained by some genetic determination. For instance, in the 57 studies of general population samples of Africans in 17 African countries, all the IQs lie in the range between 59 and 88 (Table 4.1), and in the 14 Caribbean and Latin American countries all the IQs lie in the range between 60 and 80 (Table 4.3). Similarly, in the 58 studies of indigenous East Asians in 6 countries all the IQs in lie in the range between 100 and 120 (Table 10.1). Only a genetic factor can explain the consistency of these race differences in so many different environments. It is curious that those who support the environmentalist theory of race differences in intelligence, such as Neisser (1996), Mackintosh (1998), Jencks and Phillips (1998), Nisbett (1998), Flynn (1980), Fish (2002), and Brody (2003), fail to make any mention of the consistency of the racial differences in so many different environments and nations.

Third, the races differ consistently in IQ when they live in the same environments. Thus, Africans in the United States, Britain, the Netherlands, and Brazil consistently have.lower IQs than whites. The same is true of South Asians and North Africans in Britain, Continental Europe, Africa, Fiji, Malaysia, and Mauritius; of Native Americans living with Europeans in the United States, Canada, and Mexico; of Arctic Peoples living with Europeans in Canada; of Australian Aborigines living with Europeans in Australia; and of Pacific Islanders living with Europeans in New Zealand and Hawaii. All these differences are consistent and add to the credibility of the genetic theory.

Fourth, when babies from other races are adopted by Europeans in Europe and the United States, they retain the IQs characteristic of their race. This has been shown for Africans in the United States, where black infants adopted by white middle class parents have the same IQ as blacks reared in their own communities (Lynn, 1994c); for Australian Aborigines in Australia; and for East Asians in the United States and Europe, where Korean infants adopted by Europeans have IQs in the range between 102 and 110 (Table 10.4) shown in Chapters 4, 8, and 10, respectively.

Fifth, mixed-race individuals have IQs intermediate between those of the two parent races. Thus, in the Weinberg, Scarr, and Waldman (1992) study of children adopted by white middle class families, at the age of 17 years blacks had an IQ of 89, those of mixed black-white parentage an IQ of 98, and whites an IQ of 106 (Lynn, 1994c). When the amount of European ancestry in American blacks is assessed by skin color, dark-skinned blacks have an IQ of 85 and light-skinned blacks have an IQ of 92 (Lynn, 2002a), and there is a statistically significant association between light skin and intelligence.

Similarly, mixed-race Australian Aborigines have IQs intermediate between full-blooded Aborigines and Europeans (Chapter 8, Section 2); and mixed-race Native Americans have IQs intermediate between full-blooded Native Americans and Europeans (Chapter 12, Table 12.4).

Sixth, the IQs of races explain the extent to which they made the Neolithic transition from hunter gathering to settled agriculture. This transition was made completely by the more intelligent races: the Europeans, the South Asians and North Africans, the East Asians, the Southeast Asians, and the Native Americans; to some extent by the Pacific Islanders, who were handicapped by living in small and dispersed populations on small islands; minimally by the Africans; but not at all by the Bushmen and Australian Aborigines, with IQs of 54 and 62, who have made virtually no progress in the transition from hunter-gatherers to settled agricultural societies. The only anomaly is the Arctic Peoples, with their IQ of 91, who remain largely hunter-gatherers, but this is due to their very small and dispersed populations and the harsh climate of the Arctic Circle.

Seventh, the IQs of races are consistent with their achievements in the development of early urban civilizations with written languages, systems of arithmetic, and codified laws as shown by Baker (1974), who has documented that only the East Asians, the Europeans, the South Asians and North Africans, and the Southeast Asians developed early civilizations. The less intelligent Native Americans developed a half civilization; and the remaining races failed to develop anything that could be called civilizations. The anomalies of the Pacific Islanders and Arctic Peoples, with their IQs of 90 and 91, neither of which has ever developed anything resembling a civilization, can be explained in the case of the Pacific Islanders as due to their very small and dispersed populations on isolated islands and, in the case of the Arctic Peoples, the severity of their climate, which has made it impossible to sustain urban civilizations. These race differences that Baker (1974) analyzed in the development of early civilizations in the period between approximately BC 4000 and 500 have persisted from 1 AD to the present. Virtually all the advances that have been made in the last two thousand years in science, mathematics, technology, and the arts have been made by the East Asians and the Europeans, with some small input from the South Asians and North Africans. This has been documented in detail by Murray (2003), although he analyzes these advances by geographic region and refrains from pointing out that it has been almost exclusively the East Asian and European peoples who have made these advances. The achievements of the races in making the Neolithic transition, in the development of early civilizations, and in the advances of mature civilizations during the last two thousand years show that the differences in intelligence go back many thousands of years and are a further expression of genetically based race differences in intelligence.

Eighth, all the twin studies that have been carried out in Europe, India, and Japan, and on blacks and whites in the United States, have found a high heritability of intelligence in national populations. It is improbable that these high heritability within races could co-exist with the absence of any heritability for the differences between the races.

Ninth, there are race differences in brain size that are associated with differences in intelligence, and brain size has a heritability of 90 percent (Baare, Pol et al., 2001) (see also Rushton and Osborne, 1995). The only reasonable interpretation of this association is that the races with the higher intelligence have evolved larger brains to accommodate their higher IQs. A further elaboration of this point is given in Chapter 16, sections 3 through 6.

Tenth, the consistency of all the racial differences in so many different nations, in the development of -early and later civilizations, and the high heritability of intelligence wherever it has been investigated, all need to be considered in terms of Popper's (1959) theory of the logic of scientific explanation. This states that a scientific theory generates predictions that are subjected to empirical testing. A strong theory has few assumptions and generates a large number of predictions that are empirically verified. If the predictions are disconfirmed the theory is weakened and may even be destroyed, although a single disconfirmation can generally be explained or the theory can be modified to account for it. For the problem of race differences in intelligence, the theory that these have some genetic basis explains all the numerous phenomena set out in the points listed above, and there are no serious anomalies. The theory that the race differences in intelligence are to a significant extent genetically based fulfills Popper's criteria for a strong theory. Those who assert that there is no evidence for a genetic basis of racial differences in intelligence betray a lack of understanding of the logic of scientific explanation.
Profile Image for Khalid.
90 reviews12 followers
December 8, 2009
Richard Lynn analyzes the results of over 500 published studies that span ten population groups—races and sub-races worldwide—. This comprehensive review of worldwide racial differences of general intelligence explores the formation of races, meaning of intelligence, validity of race differences in IQ, environmental and genetic correlates of intelligence, the relationship between brain size and intelligence, the evolution of racial differences in intelligence, and the factor of racial hybrids. Lynn expands upon an extensive array of research findings from the biomedical and social sciences, including the latest studies from the fields of behavior genetics, evolutionary psychology, and anthropology in reaching his thought-provoking conclusions. Lynn’s meta-analysis lists East Asians on top with Europeans second to Bushmen and Pygmies on the bottom of the list. One of the worest books ever! No real Scientific evidence.
Profile Image for AttackGirl.
1,680 reviews26 followers
February 17, 2024
2024, 5x times now and well perhaps more opposed now as if he has a chip on his shoulders with no science to support his fists.

2022
Except I do not support the excuse of environmental demands one aspect of IQ is the capability to understand faster regardless of task.

Again everyone who knows me or reads my posts knows I support DNA only theory not environmental impacts for offspring the alleles can turn on and off but won’t if they are not on the DNA strand.
Profile Image for ChancelerTrust.
14 reviews
January 13, 2026
"the races have become genetically differentiated for all characteristics for which there is genetic variation, including body shape; color of skin, hair, and eyes; prevalence of genetic diseases; and blood groups. It is inconceivable that intelligence would be the single exception to these differences"

This book speaks of an taboo, if you bring up any of the conclusions taken from this book in an academic context you might have your entire career and life ruined. First, it argues that IQ is a legitimate way of measuring general intelligence (the g factor), and once that's done, if you measure the IQ of people based on their races (this also pressuposes the big no-no in all of modern academia: Race is real), there is significant gaps between populations, and third, those differences can't be exclusively attributed to environmental causes but are, in fact, genetic differences woven across thousands of years by founder effects, genetic drifts, mutations, and adaptations.

Most of the first part of the book is quite dry and is an exposition of the research done on IQs among different races, the synthesis from it is an obvious hierarchy: at the top you have East Asians and Europeans with IQs of around 100 to 115; in the middle tier Africans outside Africa, Pacific Islanders, MENA and Southeast Asians with IQs of around 85-90; and at the very bottom you have Bushmen, Australian Aborigines, and Sub-Saharan Africans with IQs of around 50-67 (note how african-americans have higher IQs than pure africans, due not only to environmental reasons but also genetic ones).

"[...] there is a statistically significant association between light skin and intelligence."

Most of the second part of the book regards evolutionary history and hypotheses, which are highly speculative by nature, the conclusion Lynn draws from the sources he uses is that temperate and cold environments act as selection pressure that leads to the evolution of higher intelligence, while for many reasons those who stayed in the tropics didn't (Lynn works with the Out of Africa model here).

The black-pilled conclusion that the book doesn't state outright, but one can take from it is: if the reasons for these disparities are ingrained in thousands of years of adaptation, the rate at which the IQ gap can be closed will never exceed the rate at which humans undergo evolution.


Modern Society which was built and is mainly kept by Eurasians, cannot be shared equally with people that less than some centuries ago were living a hunter-gatherer lifestyle, and no amount of 'education' and 'assimilation' (which really is a form of violence towards these people when you get down to it) is going to help that, and if you need any proof of the validity of this thesis, just take a look at all the African nations once the Europeans left.
Profile Image for Céleste.
9 reviews
April 21, 2025
The data is clearly cherry-picked to dismiss any possible non-racist explanation. Total garbage, an insult to science.
76 reviews4 followers
December 28, 2024
Holy cow there’s a lot of studies in this book. A large collection of studies, evidences, and arguments pertaining to racial differences in intelligence, with origins coming from the cold winters theory of intelligence. There is a wide body of evidence to suggest that CWT is incorrect, simplistic and fails to account various observations especially in the realm of cranial capacity and select African populations. Africa’s development and the mental development of Blacks outside Africa is a much richer subject than Lynn’s book here provides.
Profile Image for Илья Дескулин.
90 reviews16 followers
January 2, 2024
This is a typical Lynn's book: brutal, based and boring. The author neither tries to be nice nor entertaining. He just bombards you with facts, logic and... tables. Some evolutionary explanations of the IQ gaps should be updated though: temperature and size of population is not the whole story. The Russian translation exists, but it is horrible.
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