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Wicherts et al on African I.Q.s, Lynn ThesisEdit

Controversial Study of African IQ Levels Is 'Deeply Flawed'

ScienceDaily (Jan. 21, 2010) - The controversial study on African IQ levels conducted by psychologist Richard Lynn is deeply flawed. This conclusion is the outcome of studies by Jelte Wicherts, Conor Dolan, Denny Borsboom and Han van der Maas of the University of Amsterdam (UvA) and Jerry Carlson of the University of California (Riverside).

Their findings are set to be published in Intelligence, Personality and Individual Differences, and Learning and Individual Differences.

In an oft-quoted literature study conducted in 2006, Lynn concluded that black Africans have an average IQ of less than 70 (compared to an average western IQ of 100). Lynn suggested that these low IQs are indicative of a low intelligence level, claiming this offered an explanation for the low level of economic development in sub-Saharan countries.

Lynn's study is well known among psychologists, and has been referenced by academics such as Nobel laureate James Watson, and the authors of the controversial book The Bell Curve -- Intelligence and Class Structure in America (Richard Herrnstein and Charles Murray: Freepress, 1994).

African IQ scores prove flawed

Wicherts and his colleagues examined over 100 published studies, concluding that there is no evidence to back up Lynn's claims. Amongst other flaws, Lynn used selective data by systematically ignoring Africans with high IQ scores. The researchers also claim that African IQ test scores cannot be interpreted in terms of lower intelligence levels, as these scores have different psychometric characteristics than western IQ test scores. Until now, the incomparability of Western and African IQ scores had never been systematically proven.

The scientists point out that the average African IQ is currently comparable to the average level in the Netherlands around 1950. However, IQ scores in Western countries have risen sharply over the course of the 20th century. In view of this trend, Wicherts and his colleagues claim there are no reasonable grounds to conclude that sub-Saharan countries are poor due to the lower IQ scores of their populations. As it turns out, the average IQ of African adults is seeing a similar rising trend, which is expected to continue if living conditions in Africa improve in future.

Story Source:

   Adapted from materials provided by Universiteit van

Amsterdam (UVA).

Journal References:

[see below]

Personality and Individual Differences
Volume 48, Issue 2, January 2010, Pages 91-96
Copyright c 2009 Elsevier Ltd All rights reserved.


Why national IQs do not support evolutionary theories of intelligence

Jelte M. Wicherts, Denny Borsbooma and Conor V. Dolana

aDepartment of Psychology, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands

Received 16 February 2009; revised 19 May 2009; accepted 26 May 2009. Available online 24 June 2009.


Kanazawa (2008), Templer (2008), and Templer and Arikawa (2006) claimed to have found empirical support for evolutionary theories of race differences in intelligence by correlating estimates of national IQ with indicators of reproductive strategies, temperature, and geographic distance from Africa. In this paper we criticize these studies on methodological, climatic, and historical grounds. We show that these studies assume that the Flynn Effect is either nonexistent or invariant with respect to different regions of the world, that there have been no migrations and climatic changes over the course of evolution, and that there have been no trends over the last century in indicators of reproductive strategies (e.g., declines in fertility and infant mortality). In addition, we show that national IQs are strongly confounded with the current developmental status of countries. National IQs correlate with all the variables that have been suggested to have caused the Flynn Effect in the developed world.

Keywords: Evolutionary psychology; Flynn Effect; Race differences

Article Outline

1. Introduction
2. Temporal constancy over the course of evolution?
3. Climate change
4. Changes in reproductive strategies
5. Migration and geographic distance
6. The temporal stability of IQ-scores
7. The many confounds of national IQ
8. Method
9. Results
10. Discussion

Corresponding author. Tel.: +31 205257067.

Personality and Individual Differences
Volume 48, Issue 2, January 2010, Pages 104-106
Copyright c 2009 Elsevier Ltd All rights reserved.

Short Communication

Evolution, brain size, and the national IQ of peoples around 3000 years B.C

Jelte M. Wicherts a, Denny Borsboom a and Conor V. Dolan a

aUniversity of Amsterdam, Department of Psychology, Amsterdam, The Netherlands

Received 22 August 2009; accepted 26 August 2009. Available online 18 September 2009.


In this rejoinder, we respond to comments by Lynn, Rushton, and Templer on our previous paper in which we criticized the use of national IQs in studies of evolutionary theories of race differences in intelligence. We reiterate that because of the Flynn Effect and psychometric issues, national IQs cannot be taken to reflect populations' levels of g as fixed since the last ice age. We argue that the socio-cultural achievements of peoples of Mesopotamia and Egypt in 3000 B.C. stand in stark contrast to the current low level of national IQ of peoples of Iraq and Egypt and that these ancient achievements appear to contradict evolutionary accounts of differences in national IQ. We argue that race differences in brain size, even if these were entirely of genetic origin, leave unexplained 91-95% of the black-white IQ gap. We highlight additional problems with hypotheses raised by Rushton and Templer. National IQs cannot be viewed solely in evolutionary terms but should be considered in light of global differences in socio-economic development, the causes of which are unknown.

Keywords: Evolutionary psychology; Flynn Effect; Race differences; Brain size

Article Outline

1. Introduction
2. IQ avant la lettre
3. Brain size
4. The Big picture
5. Conclusion

Corresponding author. Address: Department of Psychology, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands. Tel.: +31 205257067.

Volume 38, Issue 1, January-February 2010, Pages 1-20
Copyright c 2009 Elsevier Inc. All rights reserved.

A systematic literature review of the average IQ of sub-Saharan Africans

Jelte M. Wicherts, Conor V. Dolan a and Han L.J. van der Maas a

a Department of Psychology, Psychological Methods, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands

Received 8 October 2008; revised 6 May 2009; accepted 12 May 2009. Available online 9 June 2009.


On the basis of several reviews of the literature, Lynn [Lynn, R., (2006). Race differences in intelligence: An evolutionary analysis. Augusta, GA: Washington Summit Publishers.] and Lynn and Vanhanen [Lynn, R., & Vanhanen, T., (2006). IQ and global inequality. Augusta, GA: Washington Summit Publishers.] concluded that the average IQ of the Black population of sub-Saharan Africa lies below 70. In this paper, the authors systematically review published empirical data on the performance of Africans on the following IQ tests: Draw-A-Man (DAM) test, Kaufman-Assessment Battery for Children (K-ABC), the Wechsler scales (WAIS & WISC), and several other IQ tests (but not the Raven's tests). Inclusion and exclusion criteria are explicitly discussed. Results show that average IQ of Africans on these tests is approximately 82 when compared to UK norms. We provide estimates of the average IQ per country and estimates on the basis of alternative inclusion criteria. Our estimate of average IQ converges with the finding that national IQs of sub-Saharan African countries as predicted from several international studies of student achievement are around 82. It is suggested that this estimate should be considered in light of the Flynn Effect. It is concluded that more psychometric studies are needed to address the issue of measurement bias of western IQ tests for Africans.

Keywords: Group differences; Black-White differences; Flynn Effect; Race differences; Cross-cultural comparison; National IQ

Article Outline

1. Scholastic achievement surveys
2. A systematic review of the literature
3. Method
3.1. Search of studies
3.2. Our inclusion criteria
3.2.1. Norms
3.2.2. Standardized test administration of entire IQ test
3.2.3. No reported problems during testing
3.2.4. No measurement bias
3.2.5. Normal samples
3.3. Statistical analyses
4. Results
4.1. Draw-a-Man test
4.2. Kaufman-Assessment Battery for Children
4.3. Wechsler Scales
4.4. Culture Fair Intelligence Test
4.5. Other IQ tests
4.6. Meta-analytic analyses
4.7. Publication bias
5. Conclusion
Appendix A. Appendix

Corresponding author. Tel.: +31 205257067; fax: +31 206390026.

Volume 38, Issue 1, January-February 2010, Pages 30-37
Copyright c 2009 Elsevier Inc. All rights reserved.

The dangers of unsystematic selection methods and the representativeness of 46 samples of African test-takers

Jelte M. Wicherts, Conor V. Dolan a and Han L.J. van der Maas a

a University of Amsterdam, The Netherlands Received 13 October 2009; accepted 6 November 2009. Available online 3 December 2009.


In this rejoinder, we criticize Lynn and Meisenberg's (this issue) methods to estimate the average IQ (in terms of British norms after correction of the Flynn Effect) of the Black population of sub-Saharan Africa. We argue that their review of the literature is unsystematic, as it involves the inconsistent use of rules to determine the representativeness and hence selection of samples. Employing independent raters, we determined of each sample whether it was (1) considered representative by the original authors, (2) drawn randomly, (3) based on an explicated stratification scheme, (4) composed of healthy test-takers, and (5) considered by the original authors as normal in terms of Socio-Economic Status (SES). We show that the use of these alternative inclusion criteria would not have affected our results. We found that Lynn and Meisenberg's assessment of the samples' representativeness is not associated with any of the objective sampling characteristics, but rather with the average IQ in the sample. This suggests that Lynn and Meisenberg excluded samples of Africans who average IQs above 75 because they deemed these samples unrepresentative on the basis of the samples' relatively high IQs. We conclude that Lynn and Meisenberg's unsystematic methods are questionable and their results untrustworthy.

Keywords: Systematic literature review; National IQ; Group differences in IQ

Article Outline

1. Introduction
2. The full database
3. Inconsistent rules to determine representativeness
4. What is representative?
5. Conclusion
Appendix A. Supplementary data

Corresponding author. Department of Psychology, Psychological Methods, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands. Tel.: +31 205257067; fax: +31 206390026.

Learning and Individual Differences
Article in Press, Corrected Proof - Note to users
Copyright c 2009 Elsevier Inc. All rights reserved.

Raven's test performance of sub-Saharan Africans: Average5 performance, psychometric properties, and the Flynn Effect

Jelte M. Wicherts a, Conor V. Dolan a, Jerry S. Carlson b and Han L.J. van der Maas a

a Department of Psychology, Psychological Methods, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands

b University of California, Riverside, United States

Received 19 May 2009; revised 19 November 2009; accepted 3 December 2009. Available online 16 December 2009.


This paper presents a systematic review of published data on the performance of sub-Saharan Africans on Raven's Progressive Matrices. The specific goals were to estimate the average level of performance, to study the Flynn Effect in African samples, and to examine the psychometric meaning of Raven's test scores as measures of general intelligence. Convergent validity of the Raven's tests is found to be relatively poor, although reliability and predictive validity are comparable to western samples. Factor analyses indicate that the Raven's tests are relatively weak indicators of general intelligence among Africans, and often measure additional factors, besides general intelligence. The degree to which Raven's scores of Africans reflect levels of general intelligence is unknown. Average IQ of Africans is approximately 80 when compared to US norms. Raven's scores among African adults have shown secular increases over the years. It is concluded that the Flynn Effect has yet to take hold in sub-Saharan Africa.

Keywords: Black-White differences; Cognitive abilities; Cross-cultural comparison; Measurement equivalence; Measurement invariance

Article Outline

1. Introduction
2. Is average IQ of Africans really below 70?
2.1. Method
2.1.1. Selection bias
2.1.2. Search of studies
2.1.3. Exclusion criteria
2.1.4. Converting raw scores to IQ
2.2. Results
2.2.1. Raven's Standard Progressive Matrices
2.2.2. Coloured Progressive Matrices
2.3. Conclusion on the average IQ of Africans
3. The Flynn Effect
3.1. Flynn Effect in Africa
4. Measurement problems and psychometric comparability
4.1. Reliability
4.2. Convergent validity
4.3. Factor analytical results
4.4. Measurement invariance
4.5. Criterion validity in educational settings
4.6. Conclusion on psychometric properties
5. General discussion
Appendix A. Appendix

Converting raw scores to IQs

Appendix B. Appendix References

Corresponding author. Tel.: + 31 205257067; fax: + 31 206390026.

Removal of mapsEdit

Could we get an explanation for the removals of the maps? Obviously some of the stated reasons for the removal of the list does not apply. A map does not attract vandals and there is no possible copyright issue. The issue of "truth" is not something that Wikipedia aims to judge so an inclusion in Wikipedia is not a endorsement of correctness of the national IQ scores. Rather, the scores has caused widespread debate both inside and outside academia and have been used in many peer-reviewed studies (such as a number of studies finding high correlations with several international student assessment tests and there are many studies examining how other factors are associated with the national IQ scores [1][2])so they are notable which is a criteria for inclusion. Acadēmica Orientālis (talk) 05:16, 1 March 2012 (UTC)

It is pure censorship, sinister and extremely worrying. Wikipedia should not be governed by the thought police. There is no coherent and logical reason for the removal of this content.Rangoon11 (talk) 15:55, 26 March 2012 (UTC)
I also strongly oppose any kind of censorship. Just because reality is more bleak than what you want it to be is not a reason to hide facts of a scientific nature. Yes, reality can be quite offensive. However, the computer on which you edit Wiki would not exist had a few brave men not gone against politically-correct worldviews (like that of the Inquisition back in the day). If you want to prove Lynn wrong, the proper avenue is to go to Africa and measure the IQs of people there yourself, and present your data to the world - not to hide his findings for fear they might offend others.--Wyqtor (talk) 08:04, 17 May 2012 (UTC)
This article exists because of the controversy surrounding the book and Lynn's use of data, in a highly questionable manner, in order to prove his point. Any "reality" is purely of Lynn's making. —ArtifexMayhem (talk) 20:45, 17 May 2012 (UTC)
Any evidence for that claim?Rangoon11 (talk) 21:48, 17 May 2012 (UTC)
Try this or the other sources found in the article itself. —ArtifexMayhem (talk) 04:02, 18 May 2012 (UTC)
That is a book review, an interesting read but not a piece of evidence, and it is clearly pushing a certain narrow viewpoint. And many of the premises within it are really rather curious. For example, what is the definition of "middle class" - it is a wholly unscientific concept. Are "working class" people in China and Japan and South Korea supposed to have a lower IQ than those in the "middle class"? Or an IQ the same as "working class" people in Africa? Why do different racial groups within countries have markedly different IQ scores, with for example a very large gap between Askenazi Jews and blacks in the US?
We are still left with the key point that information which is very key to understanding the topic of this article - the actual IQ results - is being withheld from readers as if they are children who might be given bad dreams. By all means let's have a detailed discussion in the article on the merits of both the actual collection of the IQ data (which I think most would agree was imperfect), and on the analysis given in the book about the relationship between IQ and national wealth. And in that we can also mention alternative theories such as that given in the book review about the size of the middle class.
But please let's not practice censorship in WP, and try to shy away from things which we may find uncomfortable.Rangoon11 (talk) 14:35, 18 May 2012 (UTC)
From WP:CENSOR: Discussion of potentially objectionable content should not focus on its offensiveness but on whether it is appropriate to include in a given article. None of the rationales given for not including the data have relied on offensiveness. Your repeated attempts to imply that the data was removed because it was offensive are hollow, pointless, and verging on disruptive. aprock (talk) 20:23, 18 May 2012 (UTC)
Its not censorship its the removal of non encyclopedic content. visual candy of made up numbers that reflect nothing other than the prejudice of the creators.-- TRPoD aka The Red Pen of Doom 01:08, 31 August 2014 (UTC)

edit requestEdit

That the chart of national estimates of IQ be removed.

Per the previous discussions, there has been no consensus to indicate that the inclusion of the numbers: 1) provides additional encyclopedic information about the subject of the article - a book which put forth a widely discredited theory, and in fact due to the length and visual eyemagnet of the huge chart obscures that fact which is the most notable feature of the book 2) does not to a casual reader present the discredited information in a way that appears that Wikipedia is endorsing it 3) does not violate copyright as a very significant portion of creative method of arriving at the numbers. -- The Red Pen of Doom 16:18, 29 June 2012 (UTC)

I'm new here, but while it's fairly obvious, I suspect it might be desirable to spell out that the table with bold heading "IQ estimates given in the book" (down to heading "Special cases") should be removed because it is reproducing key points from the book (such reproduction does seem at least unethical, although I don't know about the copyright situation). Johnuniq (talk) 02:22, 10 July 2012 (UTC)
yes, that is the portion that should be removed. -- The Red Pen of Doom 03:00, 10 July 2012 (UTC)
re copyright see this [3] and then IQ_and_the_Wealth_of_Nations#National_IQ_estimates and then IQ_and_the_Wealth_of_Nations#Criticism_of_data_sets -- The Red Pen of Doom 03:07, 10 July 2012 (UTC)

Note: The table was flagged as Copyvio here, and the table was removed by clerk and closed at Wikipedia:Copyright_problems/2012_April_13 after removal. --Tgeairn (talk) 03:36, 10 July 2012 (UTC)

Copyright in listsEdit

Lists of uncreative fact are not copyrighted in the U.S. However, one must be clear that a list is "fact" and not speculation. See Wikipedia:Copyright in lists. There is ample evidence that this list is not purely formulaic, including that the authors did not use consistent standards even within their own work: "In some cases, the IQ of a country is estimated by averaging the IQs of countries that are not actually neighbors of the country in question. For example, Kyrgyzstan's IQ is estimated by averaging the IQs of Iran and Turkey, neither of which is close to Kyrgyzstan."

The copyright question, of course, can be overcome in the same way that all copyright issues are overcome - by seeking and obtaining permission. Wikipedia:Requesting copyright permission gives some recommended text; it's generally a good idea to start with the publishing house, as this is a service they're used to. That would leave the editors of this article needing only to assess other inclusion factors, since the copyright barrier would be removed. --Moonriddengirl (talk) 12:42, 10 July 2012 (UTC)

A redirect for discussionEdit

National IQ and National iq have previously or currently directed to this article. Those redirects have been nominated for discussion at Wikipedia:Redirects_for_discussion/Log/2012_July_10#National_IQ. -- The Red Pen of Doom 18:47, 10 July 2012 (UTC)

Criticism of IQ tests, bias against tropical populationEdit

Not only there is problems of data sets of the IQ tests, common IQ tests are criticized. This Criticism should appear in the article too. The tests are designed for European population and their descendents. They are biased against tropical population. Asian performs well partly because they are genetically closely related to Europeans. See

IQ test assume that certain mental capacity are important. Evolutionary speaking, those features only serve the needs of animals(humans are animals) within their own environment. Tropical population have lots of distinguish capacities to survive in their very different environment. But those capacities are not measured by the common IQ test. see the link for more information:

I am from a region with a high average IQ on the chart. I am not trying to say my population is smart so my opinion is true. In stead, I am trying to say I don't have conflict interests regard my view of tropical population. I think the study is unscientific although it makes my population look good. — Preceding unsigned comment added by (talk) 04:34, 19 September 2013 (UTC)

IQ tests are not designed to measure fitness in the sense of natural selection, i.e. fitness for an ancestral environment and needs. They are designed to measure intelligence. The claim made by IQ and the Wealth of Nations, and also at least four other scholarly books published since then, is that national average IQ varies by nation and is correlated with economic success. So your criticism seems misplaced, and you would need to find a reliable source that explicitly makes the same criticism of this book, otherwise to insert it into the article would be WP:SYNTHESIS.--greenrd (talk) 20:49, 20 February 2017 (UTC)

The g-Factor of International Cognitive Ability Comparisons: The Homogeneity of Results in PISA, TIMSS, PIRLS and IQ-Tests Across NationsEdit

HEINER RINDERMANN* Institute of Psychology, Otto-von-Guericke-University Magdeburg, Germany

Factor analyses were done with MPLUS statistical software using Full-InformationMaximum-Likelihood (FIML; Raykov, 2005). This kind of analysis allows for the use of all data (no listwise deletion of a country and all its information if one observation in one variable is missing). In a factor analysis the first unrotated factor (g-factor) explained 94% (unadjusted) or 95% (adjusted) of the variance of the 20 student assessment scales and the intelligence test collection of Lynn and Vanhanen (see Table 1 and Figure 1 a,b).

This research actually wallidates the work of Lynn and Vanhanen.

Return to "IQ and the Wealth of Nations" page.