Race Differences in Intelligence
Encyclopedia
Race Differences in Intelligence: An Evolutionary Analysis is a 2006 book by controversial race and intelligence
writer Richard Lynn
reviewing the worldwide literature on IQ testing and arguing for in part genetic racial differences and with a discussion on the causes and consequences.
, the book was published by Washington Summit Publishers
. It was followed in 2008 by The Global Bell Curve
. Lynn's survey is an expansion by nearly four times of the data collected in his 2002 book IQ and the Wealth of Nations
with Tatu Vanhanen
, which dealt with the relationship between IQ and economic development.
The book claims to represent the largest collection and review of the global Intelligence Quotient
(IQ) data, surveying 620 published studies from around the world, with a total of 813,778 tested individuals. Lynn's meta-analysis lists East Asians (IQ 105), European
s (100), Inuit
(91), South East Asians (87), Native Americans (87), Pacific Islanders
(85), South Asians and North Africans (84), non-bushmen Sub-Saharan Africans (67), Australian Aborigines
(62), Bushmen
and Pygmies (54). The average human IQ of the world is estimated to be 90.
Lynn defines races as the genetic clusters or ancestral population groups identified in previous genetic cluster analysis by Luigi Cavalli-Sforza and his colleagues in their 1994 book The History and Geography of Human Genes. Many current ethnic groups would be mixtures of these races. See also the Race and genetics article.
The book defends the reliability and validity of the measures. When taken as national averages, the data available, particularly regarding the developing world, is uncertain due to limited sampling, year of testing, and varying type of cognitive ability test used. Lynn argues that, though additional evidence may be required to confirm some of the racial IQ estimates, the surveyed studies have high reliability
in the sense that different studies give similar results. For instance, East Asians invariably obtain high IQs, not only in their own native homelands but also in Singapore, Malaysia, Hawaii, and North America. He also argues that they high validity
in the sense that they correlate highly with performance in international studies of achievement in mathematics
and science
and with national economic development.
Broadly speaking, Lynn estimates that about half of the IQ deficit of third world races can be explained by inadequate nutrition, while the other half is racially genetic. For example Lynn argues that while Africans living in Africa average IQ 67, African Americans living in the Southern United States (where European admixture is very low) average IQ 80. Lynn believes the latter figure represents their genotypic intelligence, while the IQs in Africa are stunted by malnutrition
.
Ashkenazi Jews
who Lynn classifies as West Asian/European hybrids, average 108-115 in the U.S. and Britain
. Israel
has an average IQ of only about 95. Lynn explains this by breaking down the Israeli population into three components: 40 percent Ashkenazi Jews (European Jewish) with an average IQ of 103; 40 percent Sephardi Jews
(Oriental Jewish) with an average IQ of 91; and 20 percent Arab with an average IQ of 86. Lynn suggests these differences could have arisen from selective migration
(more intelligent Jews emigrated to Britain
and the USA), intermarriage with neighboring populations with different average IQs, selective survival through persecution (European Jews were the most persecuted), and the presence of ethnic non-Jews among the Ashkenazim in Israel as a result of the immigration of people from the former Soviet Bloc countries who posed as Jews. See also the article on Ashkenazi intelligence
.
Lynn argues that as early humans migrated out of Africa there was the cognitively demanding problem of cold winters with no plant food. These problems became much greater in the last ice age that began about 28,000 years ago and lasted until about 11,000 years ago. This required greater intelligence than was needed in tropical and semi-tropical equatorial Africa where plant foods are plentiful throughout the year and regulating temperature is easier. However, he writes that the Inuit
, who lives in the coldest climate, do not have the highest average IQ. He explains this by a larger population density increasing the number of beneficial mutation
s and increasing interactions between groups of people which increases the speed by which advantageous genes can spread.
(2002) received many criticisms, as discussed in that article, which may or may not be relevant for his later works.
Psychology professor J. Philippe Rushton
, who has argued for many of the same conclusions as Lynn and serves with Lynn on the board of the Pioneer Fund
, wrote a favorable review.
A review by Nicholas Mackintosh
, Emeritus Professor in the Department of Experimental Psychology
, University of Cambridge
, expresses astonishment that Lynn infers that Kalahari bushmen, with an average measured IQ of 54, should be regarded as mentally retarded; and that an 8 year old European child with the equivalent mental age would have no problems surviving in the same desert
environment. Mackintosh questions Lynn's hypothesis that migration to more harsh northern climates and ice ages selected for higher IQ by pointing to harshness of environments such as the Australian Outback
. Lynn argues that racial differences in brain size indicates different evolutionary pressure on intelligence. Mackintosh argues that the cranial capacity of early Homo sapiens, 100,000 or more years ago, was rather greater than that of modern Europeans. He criticizes Lynn for reporting data incorrectly, in some cases from studies by Mackintosh himself. He write "The errors may not be particularly important, and I do not know how typical they are. But they do not increase my confidence in Lynn's scholarship." He also writes:
A review by John C. Loehlin
, University of Texas Professor emeritus, argues that the general trends in the data that Lynn presents are probably dependable, but faults Lynn for carelessness in how his conclusions are presented. Loehlin summarizes his view of the book as follows:
In a 2008 review of the data used in Lynn's book, Hunt and Wittmann write:
Race and intelligence
The connection between race and intelligence has been a subject of debate in both popular science and academic research since the inception of intelligence testing in the early 20th century...
writer Richard Lynn
Richard Lynn
Richard Lynn is a British Professor Emeritus of Psychology at the University of Ulster who is known for his views on racial and ethnic differences. Lynn argues that there are hereditary differences in intelligence based on race and sex....
reviewing the worldwide literature on IQ testing and arguing for in part genetic racial differences and with a discussion on the causes and consequences.
Overview
As with Lynn's and Tatu Vanhanen's 2006 book IQ and Global InequalityIQ and Global Inequality
IQ and Global Inequality is a 2006 book by psychologist Richard Lynn and political scientist Tatu Vanhanen. IQ and Global Inequality is follow-up to their 2002 book IQ and the Wealth of Nations, an expansion of the argument that international differences in current economic development are due in...
, the book was published by Washington Summit Publishers
Washington Summit Publishers
Washington Summit Publishers produces and sells books in the categories of anthropology, evolution, genetics, psychology, philosophy, and current events....
. It was followed in 2008 by The Global Bell Curve
The Global Bell Curve
The Global Bell Curve: Race, IQ, and Inequality Worldwide is a book by Professor Richard Lynn, published by Washington Summit Publishers, June 2008...
. Lynn's survey is an expansion by nearly four times of the data collected in his 2002 book IQ and the Wealth of Nations
IQ and the Wealth of Nations
IQ and the Wealth of Nations is a controversial 2002 book by Dr. Richard Lynn, Professor Emeritus of Psychology at the University of Ulster, Northern Ireland, and Dr. Tatu Vanhanen, Professor Emeritus of Political Science at the University of Tampere, Tampere, Finland...
with Tatu Vanhanen
Tatu Vanhanen
Tatu Vanhanen is a Professor Emeritus of Political Science at the University of Tampere in Tampere, Finland...
, which dealt with the relationship between IQ and economic development.
Intelligence quotient
An intelligence quotient, or IQ, is a score derived from one of several different standardized tests designed to assess intelligence. When modern IQ tests are constructed, the mean score within an age group is set to 100 and the standard deviation to 15...
(IQ) data, surveying 620 published studies from around the world, with a total of 813,778 tested individuals. Lynn's meta-analysis lists East Asians (IQ 105), European
European ethnic groups
The ethnic groups in Europe are the various ethnic groups that reside in the nations of Europe. European ethnology is the field of anthropology focusing on Europe....
s (100), Inuit
Inuit
The Inuit are a group of culturally similar indigenous peoples inhabiting the Arctic regions of Canada , Denmark , Russia and the United States . Inuit means “the people” in the Inuktitut language...
(91), South East Asians (87), Native Americans (87), Pacific Islanders
Pacific Islands
The Pacific Islands comprise 20,000 to 30,000 islands in the Pacific Ocean. The islands are also sometimes collectively called Oceania, although Oceania is sometimes defined as also including Australasia and the Malay Archipelago....
(85), South Asians and North Africans (84), non-bushmen Sub-Saharan Africans (67), Australian Aborigines
Indigenous Australians
Indigenous Australians are the original inhabitants of the Australian continent and nearby islands. The Aboriginal Indigenous Australians migrated from the Indian continent around 75,000 to 100,000 years ago....
(62), Bushmen
Bushmen
The indigenous people of Southern Africa, whose territory spans most areas of South Africa, Zimbabwe, Lesotho, Mozambique, Swaziland, Botswana, Namibia, and Angola, are variously referred to as Bushmen, San, Sho, Barwa, Kung, or Khwe...
and Pygmies (54). The average human IQ of the world is estimated to be 90.
Lynn defines races as the genetic clusters or ancestral population groups identified in previous genetic cluster analysis by Luigi Cavalli-Sforza and his colleagues in their 1994 book The History and Geography of Human Genes. Many current ethnic groups would be mixtures of these races. See also the Race and genetics article.
The book defends the reliability and validity of the measures. When taken as national averages, the data available, particularly regarding the developing world, is uncertain due to limited sampling, year of testing, and varying type of cognitive ability test used. Lynn argues that, though additional evidence may be required to confirm some of the racial IQ estimates, the surveyed studies have high reliability
Reliability (statistics)
In statistics, reliability is the consistency of a set of measurements or of a measuring instrument, often used to describe a test. Reliability is inversely related to random error.-Types:There are several general classes of reliability estimates:...
in the sense that different studies give similar results. For instance, East Asians invariably obtain high IQs, not only in their own native homelands but also in Singapore, Malaysia, Hawaii, and North America. He also argues that they high validity
Validity (statistics)
In science and statistics, validity has no single agreed definition but generally refers to the extent to which a concept, conclusion or measurement is well-founded and corresponds accurately to the real world. The word "valid" is derived from the Latin validus, meaning strong...
in the sense that they correlate highly with performance in international studies of achievement in mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
and science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
and with national economic development.
Broadly speaking, Lynn estimates that about half of the IQ deficit of third world races can be explained by inadequate nutrition, while the other half is racially genetic. For example Lynn argues that while Africans living in Africa average IQ 67, African Americans living in the Southern United States (where European admixture is very low) average IQ 80. Lynn believes the latter figure represents their genotypic intelligence, while the IQs in Africa are stunted by malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....
.
Ashkenazi Jews
Ashkenazi Jews
Ashkenazi Jews, also known as Ashkenazic Jews or Ashkenazim , are the Jews descended from the medieval Jewish communities along the Rhine in Germany from Alsace in the south to the Rhineland in the north. Ashkenaz is the medieval Hebrew name for this region and thus for Germany...
who Lynn classifies as West Asian/European hybrids, average 108-115 in the U.S. and Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
has an average IQ of only about 95. Lynn explains this by breaking down the Israeli population into three components: 40 percent Ashkenazi Jews (European Jewish) with an average IQ of 103; 40 percent Sephardi Jews
Sephardi Jews
Sephardi Jews is a general term referring to the descendants of the Jews who lived in the Iberian Peninsula before their expulsion in the Spanish Inquisition. It can also refer to those who use a Sephardic style of liturgy or would otherwise define themselves in terms of the Jewish customs and...
(Oriental Jewish) with an average IQ of 91; and 20 percent Arab with an average IQ of 86. Lynn suggests these differences could have arisen from selective migration
Human migration
Human migration is physical movement by humans from one area to another, sometimes over long distances or in large groups. Historically this movement was nomadic, often causing significant conflict with the indigenous population and their displacement or cultural assimilation. Only a few nomadic...
(more intelligent Jews emigrated to Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
and the USA), intermarriage with neighboring populations with different average IQs, selective survival through persecution (European Jews were the most persecuted), and the presence of ethnic non-Jews among the Ashkenazim in Israel as a result of the immigration of people from the former Soviet Bloc countries who posed as Jews. See also the article on Ashkenazi intelligence
Ashkenazi intelligence
Whether Ashkenazi Jews have higher intelligence than other ethnic groups has been an occasional subject of scientific controversy. The 2005 paper "Natural History of Ashkenazi Intelligence" by Cochran, Hardy, and Harpending, argued on the basis of inherited diseases and the peculiar economic...
.
Lynn argues that as early humans migrated out of Africa there was the cognitively demanding problem of cold winters with no plant food. These problems became much greater in the last ice age that began about 28,000 years ago and lasted until about 11,000 years ago. This required greater intelligence than was needed in tropical and semi-tropical equatorial Africa where plant foods are plentiful throughout the year and regulating temperature is easier. However, he writes that the Inuit
Inuit
The Inuit are a group of culturally similar indigenous peoples inhabiting the Arctic regions of Canada , Denmark , Russia and the United States . Inuit means “the people” in the Inuktitut language...
, who lives in the coldest climate, do not have the highest average IQ. He explains this by a larger population density increasing the number of beneficial mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s and increasing interactions between groups of people which increases the speed by which advantageous genes can spread.
| Race | Mean I.Q | Mean brain size (cc) |
|---|---|---|
| East-asians (China, Taïwan, Japan, Korea) | 105 | 1416 |
| Europeans | 100 | 1369 |
| South-est asians | 90 | 1332 |
| Pacific Islanders | 85 | 1317 |
| South Asians and North africans | 84 | 1293 |
| Africans | 67 | 1282 |
| Australian aborigines | 62 | 1225 |
Reception
Lynn previous book IQ and the Wealth of NationsIQ and the Wealth of Nations
IQ and the Wealth of Nations is a controversial 2002 book by Dr. Richard Lynn, Professor Emeritus of Psychology at the University of Ulster, Northern Ireland, and Dr. Tatu Vanhanen, Professor Emeritus of Political Science at the University of Tampere, Tampere, Finland...
(2002) received many criticisms, as discussed in that article, which may or may not be relevant for his later works.
Psychology professor J. Philippe Rushton
J. Philippe Rushton
Jean Philippe Rushton is a Canadian psychology professor at the University of Western Ontario who is most widely known for his work on racial group differences, such as research on race and intelligence, race and crime, and the application of r/K selection theory to humans in his book Race,...
, who has argued for many of the same conclusions as Lynn and serves with Lynn on the board of the Pioneer Fund
Pioneer Fund
The Pioneer Fund is an American non-profit foundation established in 1937 "to advance the scientific study of heredity and human differences." Currently headed by psychology professor J. Philippe Rushton, the fund states that it focuses on projects it perceives will not be easily funded due to...
, wrote a favorable review.
A review by Nicholas Mackintosh
Nicholas Mackintosh
Nicholas John Mackintosh, FRS is a British experimental psychologist and author, specializing in intelligence, psychometrics and animal learning.-Career:...
, Emeritus Professor in the Department of Experimental Psychology
Experimental psychology
Experimental psychology is a methodological approach, rather than a subject, and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...
, University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...
, expresses astonishment that Lynn infers that Kalahari bushmen, with an average measured IQ of 54, should be regarded as mentally retarded; and that an 8 year old European child with the equivalent mental age would have no problems surviving in the same desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
environment. Mackintosh questions Lynn's hypothesis that migration to more harsh northern climates and ice ages selected for higher IQ by pointing to harshness of environments such as the Australian Outback
Outback
The Outback is the vast, remote, arid area of Australia, term colloquially can refer to any lands outside the main urban areas. The term "the outback" is generally used to refer to locations that are comparatively more remote than those areas named "the bush".-Overview:The outback is home to a...
. Lynn argues that racial differences in brain size indicates different evolutionary pressure on intelligence. Mackintosh argues that the cranial capacity of early Homo sapiens, 100,000 or more years ago, was rather greater than that of modern Europeans. He criticizes Lynn for reporting data incorrectly, in some cases from studies by Mackintosh himself. He write "The errors may not be particularly important, and I do not know how typical they are. But they do not increase my confidence in Lynn's scholarship." He also writes:
A more egregious example is provided by his treatment of the Eyferth (1961) study of two groups of illegitimate children fathered by (mostly) American black and white servicemen and brought up by their (carefully matched) German mothers. Eyferth reported an average IQ of 96.5 for the mixed race children and of 97.2 for the whites. Lynn reduces the former number to 94 to compensate for use of an old test, and compares it, not with the score of the white sample, but with an average IQ of 100 for German children. He is thus able to conclude that the IQ of these mixed race children is half way between that of Americans and Africans. He derives the same conclusion from the Weinberg, Scarr, and Waldman (1992) transracial adoption study since, at the 10-year follow-up, the mixed race children had an average IQ of 94, mid-way between the 102 of the white children and the 89 of the black children. He omits to mention one of the more salient features of this follow-up, namely, that there had been substantial attrition in the white sample—with a loss of those children with lower IQ scores, resulting in an overestimate of the white group's IQ by some 6 points.
"Much labour has gone into this book. But I fear it is the sort of book that gives IQ testing a bad name. As a source of references, it will be useful to some. As a source of information, it should be treated with some suspicion. On the other hand, Lynn's preconceptions are so plain, and so pungently expressed, that many readers will be suspicious from the outset."
A review by John C. Loehlin
John C. Loehlin
John Clinton Loehlin is an American behavior geneticist and psychology and computer science professor emeritus. Loehlin has served as president of the Behavior Genetics Association and of the Society for Multivariate Experimental Psychology....
, University of Texas Professor emeritus, argues that the general trends in the data that Lynn presents are probably dependable, but faults Lynn for carelessness in how his conclusions are presented. Loehlin summarizes his view of the book as follows:
Is this book the final word on race differences in intelligence? Of course not. But Richard Lynn is a major player, and it is good to have his extensive work on this topic together in one place. Future workers who address these matters under this or any other label will find that Lynn has done a lot of spadework for them. And they will also find that there is plenty to ponder over within these pages.
In a 2008 review of the data used in Lynn's book, Hunt and Wittmann write:
"The majority of the data points were based upon convenience rather than representative samples. Some points were not even based on residents of the country. For instance, the “data point” for Suriname was based on tests given to SurinameSurinameSuriname , officially the Republic of Suriname , is a country in northern South America. It borders French Guiana to the east, Guyana to the west, Brazil to the south, and on the north by the Atlantic Ocean. Suriname was a former colony of the British and of the Dutch, and was previously known as...
se who had migrated to the NetherlandsNetherlandsThe Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, and the “data point” for EthiopiaEthiopiaEthiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
was based on the IQ scores of a highly selected group that had emigrated to IsraelIsraelThe State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
and, for cultural and historical reasons, was hardly representative of the Ethiopian population. The data point for Mexico was based upon a weighted averaging of the results of a study of “Native American and MestizoMestizoMestizo is a term traditionally used in Latin America, Philippines and Spain for people of mixed European and Native American heritage or descent...
children in southern MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
” with result of a study of residents of Argentina. Upon reading the original reference, we found that the “data point” that Lynn and Vanhanen used for the lowest IQ estimate, Equatorial GuineaEquatorial GuineaEquatorial Guinea, officially the Republic of Equatorial Guinea where the capital Malabo is situated.Annobón is the southernmost island of Equatorial Guinea and is situated just south of the equator. Bioko island is the northernmost point of Equatorial Guinea. Between the two islands and to the...
, was actually the mean IQ of a group of Spanish children in a home for the developmentally disabled in Spain. Corrections were applied to adjust for differences in IQ across cohorts (the “Flynn” effectFlynn effectThe Flynn effect is the name given to a substantial and long-sustained increase in intelligence test scores measured in many parts of the world. When intelligence quotient tests are initially standardized using a sample of test-takers, by convention the average of the test results is set to 100...
), on the assumption that the same correction could be applied internationally, without regard to the cultural or economic development level of the country involved. While there appears to be rather little evidence on cohort effect upon IQ across the developing countries, one study in KenyaKenyaKenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
(Daley, Whaley, Sigman, Espinosa, & Neumann, 2003) shows a substantially larger cohort effect than is reported for developed countries."
See also
- Race and intelligenceRace and intelligenceThe connection between race and intelligence has been a subject of debate in both popular science and academic research since the inception of intelligence testing in the early 20th century...
- Evolution of human intelligence
- Intelligence and public policyIntelligence and public policyA large body of research indicates that intelligence measures such as Intelligence Quotient varies between individuals and between certain groups, and that they correlate with socially important outcomes such as educational achievement, employment, crime, poverty and socioeconomic status.In the...