IQ 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 part to differences in average national intelligence as indicated by national IQ estimates, and a response to critics. The book was published by the controversial Washington Summit Publishers.
Lynn and Vanhanen's research on national IQs has attracted academic attention from several fields with both praise and criticism. Various authors have cited the book to reach further conclusions from the book's statements or to criticize or find support for the book's scores, methodology, and conclusions. Several other data sets of estimated average national cognitive ability exist as explained in nations and intelligence.
|Abilities, traits and constructs|
|Models and theories|
|Fields of study|
- Chapter 1 summarizes theories of economic growth.
- Chapter 2 defines and describes intelligence.
- Chapter 3 argues that the scientific literature indicates that intelligence is a determinant of incomes and related phenomena among individuals within a number of countries.
- Chapter 4 describes the collection and determination of national IQ, presenting calculated IQs for 113 countries and estimated IQs for an additional 79 countries. This represents all countries with population greater than 40,000.
- Chapter 5 introduces a new statistic, the quality of human condition index (QHC) and 12 alternative variables that measure human conditions.
- Chapter 7 focuses on the relationship between national IQ and QHC, which Lynn and Vanhanen report to be strongly correlated.
- Chapter 8 examines the relationship between national IQ and 12 alternative variables, which Lynn and Vanhanen report are also correlated with national IQ.
- Chapter 9 discusses the genetic and environmental contributions to differences in national intelligence, and argues that racial composition of the population is a major factor.
- Chapter 10 considers the causal relationship between national IQ and important variables related to global inequality.
- Chapter 11 discusses and responds to criticisms made to Lynn and Vanhanen's theory by reviewers.
- Chapter 12 summarizes the book and discusses policy recommendations.
Significant correlations with higher national IQ were found for a number of factors: higher GDP/capita, higher adult literacy rate, higher gross tertiary education enrollment ratio, higher life expectancy at birth, higher level of democratization 2002 (Tatu Vanhanen's Index of Democratization), higher Human Development Index, higher Gender-related Development Index, higher economic growth rate, lower Gini index of inequality in income or consumption, lower population below the $2 a day international poverty line, lower measures of undernourishment, lower maternal mortality ratio, lower infant mortality rate, higher Corruption Perceptions Index, higher Economic Freedom of the World ratings, higher Index of Economic Freedom ratings, and more narrow population pyramid (MU Index).
The book received a mixed reception ranging from praise to dismissal.
In a review J. Philippe Rushton, President of the Pioneer fund that has been a long time funder of research by Lynn, writes that the book extends and answers criticisms against the earlier work in several ways. The number of nations for which there were IQ tests available increased from 81 to 113. The correlation between IQ and income per person was 0.68 which is virtually identical to the one reported in the earlier book. The book compared the IQ values for the 32 new nations for which IQ tests were available with the estimations for these nations in the earlier book which was based on averaging neighboring nations values. The correlation of 0.91 was very high. Rushton thus conclude that this method is remarkably accurate.
Rushton states that the authors also compared the results of the IQ tests for those nations where several were available (71 nations). They found a very high correlation of 0.95 and thus concluded that the IQ testing have a very high reliability regarding measuring IQ. The authors furthermore compared the national IQs to national scores of school students in tests of mathematics and science. The correlations were between 0.79 and 0.89. This, Rushton writes, establishes that the national IQs have very high validity as measures of national differences in cognitive ability.
The authors argue for a substantial role of genetics and race in explaining these differences. They were led to this conclusion from observing racial clusters regarding national IQs. Thus, the six East Asian nations all have IQs in the range between 105 and 108. The 29 European nations all have IQs in the range between 92 and 102. The 19 nations of sub-Saharan Africa all have IQs in the range between 59 and 73. Rushton thus argues that "They show that there is remarkable consistency in the IQs of nations when these are classified into racial clusters." The book also argues for feedback between genes and environment. For instance, a genetically caused high national IQ leads to high per capita incomes which enables high quality nutrition, education and health care for children which enhance their intelligence.
Kanazawa when commenting on using the book as a data source makes statements similar to Rushton's.
In an article published in European Journal of Personality, Heiner Rindermann compared the IQ scores from the book to a large number of international student assessment studies on subjects such as reading, mathematics, science, and problem solving, and found them to be highly intercorrelated. Statistical analyses indicated that the results could be explained by an underlying general cognitive ability. More than 30 commentaries on Rindermann's findings were published in the same issue of the journal.
The study A systematic literature review of the average IQ of sub-Saharan Africans by Jelte M. Wicherts and colleagues stated that:
- "For instance, Lynn and Vanhanen (2006) accorded a national IQ of 69 to Nigeria on the basis of three samples (Fahrmeier, 1975; Ferron, 1965; Wober, 1969), but they did not consider other relevant published studies that indicated that average IQ in Nigeria is considerably higher than 70 (Maqsud, 1980a,b; Nenty & Dinero, 1981; Okunrotifa, 1976). As Lynn rightly remarked during the 2006 conference of the International Society for Intelligence Research (ISIR), performing a literature review involves making a lot of choices. Nonetheless, an important drawback of Lynn (and Vanhanen)'s reviews of the literature is that they are unsystematic."
However, the study also did its own literature review on the average IQ of sub-Saharan Africans. It did not find as low a value as the book, below 70, but the estimated average value of 82 is still low compared to industrialized nations. Regarding four studies comparing and finding agreement between Lynn's estimated national IQs and the international student assessment tests, they disagree regarding sub-Saharan Africa but write "these four studies appear to validate national IQs in other parts of the world."
Richard Lynn and Gerhard Meisenberg in turn replied that "critical evaluation of the studies presented by WDM shows that many of these are based on unrepresentative elite samples" and that a further literature review, including taking into account results in mathematics, science, and reading, gave "an IQ of 68 as the best reading of the IQ in sub-Saharan Africa". Wicherts and colleagues in yet another reply stated: "In light of all the available IQ data of over 37,000 African testtakers, only the use of unsystematic methods to exclude the vast majority of data could result in a mean IQ close to 70. On the basis of sound methods, the average IQ remains close to 80. Although this mean IQ is clearly lower than 100, we view it as unsurprising in light of the potential of the Flynn Effect in Africa (Wicherts, Borsboom, & Dolan, 2010) and common psychometric problems associated with the use of western IQ tests among Africans."
Jones and Schneider commenting on the differences to the earlier book write "LV (2002) assembled results from 183 conventional IQ tests, both verbal and visual, given in 81 countries across the entire 20th century;they used hundreds of IQ tests from 113 countries across centuries in LV (2006). They aggregated these results using best practice methods to create estimates of “national average IQ” for these countries. LV show in those works as well as in Lynn (2006) that the IQ gaps between regions of the world have not appreciably changed during the 20th century."
In the summer of 2010 Lynn presented new calculated national IQs for 25 countries which had previously only been estimated from neighboring nations IQs and revised national IQs for 16 countries. "Numerous cultural, biological, economic, political and medical correlates of country-level intelligence have been demonstrated in previous studies. It is recommended that the new and updated IQs presented in this paper should be used as the best estimates of the average IQs for these countries by scholars investigating these correlates."
Associations between national IQ and other factors
Quality of human conditions index
The quality of human conditions (QHC) index was computed from five variables.
- purchasing power parity Gross National Income (PPP-GNI) per capita 2002
- adult literacy rate 2002
- gross tertiary enrollment ratio
- life expectancy at birth 2002
- the level of democratization 2002 (Tatu Vanhanen's Index of Democratization)
Values of the index range from 10.7 (Burkina Faso) to 89 (Norway). Lynn and Vanhanen write that they would have preferred to include a sixth measure, an indicator of income inequality, but that statistical data for that variable was not available for all countries. They write that the QHC index differs significantly from other widely used indexes (such as the Human Development Index) in that QHC also measures democratization. Some of their claims have received support in a 2007 study by Rindermann.
|All countries||Calculated IQ
|PPP GNI per capita 2002||0.693||0.342||0.616|
|Adult literacy rate 2002||0.642||0.655||0.655|
|Tertiary enrollment ratio||0.746||0.699||0.745|
|Life expectancy at birth 2002||0.765||0.690||0.750|
|Index of Democratization 2002||0.569||0.322||0.530|
|Excluding smallest countries||Calculated IQ
|PPP GNI per capita 2002||0.739||0.266||0.649|
|Adult literacy rate 2002||0.710||0.746||0.733|
|Tertiary enrollment ratio||0.778||0.734||0.780|
|Life expectancy at birth 2002||0.833||0.753||0.817|
|Index of Democratization 2002||0.598||0.408||0.584|
Other measures of global inequality
The relationship of national IQ to twelve other measures of global inequality were examined.
All twelve measures of global inequality are significantly correlated with the QHC index. According to the book, eleven of the twelve measures are significantly correlated with national IQ. The measures of human happiness and life satisfaction are not significantly correlated with national IQ.
Latitude and temperature
|Annual mean temperature||-0.885||1|
|PPP GNI per capita 2002||0.528||-0.407|
|Adult literacy rate 2002||0.482||-0.467|
|Tertiary enrollment ratio||0.718||-0.649|
|Life expectancy at birth 2002||0.505||-0.379|
|Index of Democratization 2002||0.512||-0.460|
National IQ and QHC values
Lynn and Vanhanen base their analysis on data gathered from a literature review. They selected IQ data from studies which covered 113 nations. For another 79 nations, they estimated the mean IQs on the basis of the arithmetic means of the measured IQs of neighboring countries. They justify this method of estimation by pointing out that the correlation between the estimated national IQs they reported in IQ and the Wealth of Nations and the measured national IQs since obtained is very high (0.913). In the chart below, these estimates have been marked with an asterisk (*). The chart also includes the measured and estimated IQs from IQ and the Wealth of Nations.
Lynn and Vanhanen calculated the national IQs in relation to a British mean of 100, with a standard deviation of 15. They adjusted all test results to account for the Flynn effect: adjustments were 2 points per decade for Raven's Progressive Matrices and 3 points per decade for all other types of tests. When two IQ studies were used from one country, their mean was calculated, whereas when three or more were available, the median was used. Lynn and Vanhanen recommend the provision of iodine and other micronutrients as a way to increase cognitive functioning in the Third World.
Theories of Race and Intelligence:
Publications of Race and Intelligence:
- IQ and the Wealth of Nations
- The Mismeasure of Man
- Race Differences in Intelligence
- The Global Bell Curve
- Richard Lynn and Tatu Vanhanen (2006). IQ and Global Inequality. Washington Summit Publishers: Augusta, GA. ISBN 1-59368-025-2
- Lynn, R. and Vanhanen, T. (2002). IQ and the wealth of nations. Westport, CT: Praeger. ISBN 0-275-97510-X
- "Relevance of education and intelligence at the national level for politics: Democracy, rule of law and political liberty" (PDF). Paper by Heiner Rindermann.
- Älykkyyden tabu murtuu? Review by J.P. Roos in Sosiologia 3/2007.
- Review by J. Philippe Rushton in Personality and Individual Differences, 2006, 41, 983-5. http://www.rlynn.co.uk/index.php?page=richard-lynn-and-tatu-vanhanen-iq-and-global-inequality-2006
- Wicherts, J. M., et al., A systematic literature review of the average IQ of Sub-Saharan Africans, Intelligence (2009), http://dx.doi.org/10.1016/j.intell.2009.05.002
- Nisbett, Richard. 2009. Intelligence and how to get it. pp. 215.
- Rindermann,H. (2007). The g-factor of international cognitive ability comparisons: The homogeneity of results in PISA, TIMSS, PIRLS and IQ-tests across nations. European Journal of Personality, 21, 6 67−706
- Lynn & Vanhanen 2002 p.2
- Temperature and evolutionary novelty as forces behind the evolution of general intelligence, Satoshi Kanazawa, Intelligence, Volume 36, Issue 2, March–April 2008, Pages 99-108 http://dx.doi.org/10.1016/j.intell.2007.04.001
- "The average IQ of sub-Saharan Africans: Comments on Wicherts, Dolan, and van der Maas", Richard Lynna and Gerhard Meisenberg, Intelligence, Volume 38, Issue 1, January–February 2010, Pages 21-29 http://dx.doi.org/10.1016/j.intell.2009.09.009
- The dangers of unsystematic selection methods and the representativeness of 46 samples of African test-takers, Jelte M. Wicherts, Conor V. Dolana and Han L.J. van der Maas, Intelligence Volume 38, Issue 1, January–February 2010, Pages 30-37
- IQ in the Utility Function: Cognitive skills, time preference, and cross-country differences in savings rates, Garett Jones and Marta Podemska, (Presented at Canadian Economics Association meetings, June 2010) http://mason.gmu.edu/~gjonesb/
- Christopher Eppig, Corey L. Fincher, and Randy Thornhill Parasite prevalence and the worldwide distribution of cognitive ability Proc R Soc B 2010: rspb.2010.0973v1-rspb20100973. http://rspb.royalsocietypublishing.org/content/early/2010/06/29/rspb.2010.0973.abstract
- IQ IN THE PRODUCTION FUNCTION: EVIDENCE FROM IMMIGRANT EARNINGS, GARETT JONES1, W. JOEL SCHNEIDER2, conomic Inquiry, Volume 48, Issue 3, pages 743–755, July 2010 http://onlinelibrary.wiley.com/doi/10.1111/j.1465-7295.2008.00206.x/full
- Mankind Quarterly, Vol. 50, No. 4 (Summer 2010) pp. 275-296, "National IQs updated for 41 Nations", Richard Lynn. http://www.mankindquarterly.org/summer2010_lynn.html
- Rindermann, Heiner: The g-factor of international cognitive ability comparisons: the homogeneity of results in PISA, TIMSS, PIRLS and IQ-tests across nations. European Journal of Personality 21 (2007) 667-706 
- Lynns posting of a favorable review that characterizes the 2006 work as a reply to criticisms of their earlier results
- A site critical of Lynn's claims
- National IQ means, calibrated on the basis of PISA scores and transformed from educational attainment