Publication on secular increases in IQ In 1982, Richard Lynn published a paper about the generational increase in performance on IQ tests, now known as the
Flynn effect slightly before
James Flynn's publications documenting the same phenomenon. A few researchers have called the phenomenon the "Lynn–Flynn effect" as a way of recognizing both their contributions. In a 2013 paper, James Flynn offered his comments on this aspect of the effect's naming:
Dysgenics and eugenics In
Dysgenics: Genetic Deterioration in Modern Populations (1996), Lynn reviewed the history of eugenics and
dysgenics, from the early writings of
Bénédict Morel and Francis Galton through the rise of eugenics in the early 20th century and its subsequent collapse. As a eugenicist himself, Lynn lists three concerns: deterioration in health, intelligence and conscientiousness. Lynn claims that, unlike modern societies, natural selection in pre-industrial societies favoured traits such as intelligence and "character". According to Lynn, those with greater educational achievement have fewer children, while children with lower IQs come from larger families. Lynn claimed that
twin studies provide evidence of a genetic basis for these differences. Lynn proposes that
conscientiousness is heritable, and that criminals tend to have more offspring. Lynn agreed with
Lewis Terman's comment in 1922 that "children of successful and cultivated parents test higher than children from wretched and ignorant homes for the simple reason that their heredity is better". A review of
Dysgenics by evolutionary biologist
W. D. Hamilton, published posthumously in 2000 in the
Annals of Human Genetics, praised the book and its endorsement of eugenics, saying "discussing the large bank of evidence that still accumulates on heritability of aptitudes and differentials of fertility, shows in this book that almost all of the worries of the early eugenicists were well-founded, in spite of the relative paucity of their evidence at the time". Psychologist
Nicholas Mackintosh, reviewing the book for the
Journal of Biosocial Science in 2002, wrote that Lynn "argues that the ideas of the eugenicists were correct and that we ignore them at our peril". Mackintosh criticised Lynn for "not fully acknowledg[ing] the negative relationship between social class and education on the one hand, and infant mortality and life expectancy on the other". He questioned Lynn's interpretation of data, and pointed out that according to Lynn's reading of the theory of natural selection, "if it is true that those with lower IQ and less education are producing more offspring, then they are fitter than those of higher IQ and more education". According to Mackintosh, eugenicist arguments such as Lynn's are not based on a "biological imperative, but rather on a particular set of value judgements". In
Eugenics: A Reassessment (2001), Lynn claimed that embryo selection as a form of standard reproductive therapy would raise the average intelligence of the population by 15 IQ points in a single generation (p. 300). If couples produce a hundred embryos, he argues, the range in potential IQ would be around 15 points above and below the parents' IQ. Lynn argues that this gain could be repeated each generation, eventually stabilising the population's IQ at a theoretical maximum of around 200 after six or seven generations.
Race and national differences in intelligence In the late 1970s, Lynn wrote that he found the average IQ of the Japanese to be 106.6, and that of
Chinese people living in Singapore to be 110. Lynn's psychometric studies were cited in the 1994 book
The Bell Curve and were criticised as part of the controversy surrounding that book. In his 2002 article, "Skin color and intelligence in African Americans", published in 2002 in
Population and Environment, Lynn concluded that lightness of skin color in African Americans is positively correlated with IQ, which he claims derives from the higher proportion of Caucasian admixture. However, Lynn failed to control for childhood environmental factors that are related to intelligence, and his research was criticised by a subsequent article published in the journal by Mark E. Hill. The article concluded that "...[Lynn's] bivariate association disappears once childhood environmental factors are considered". In his response to Hill, Lynn wrote that "The conclusion that there is a true association between skin color and IQ is consistent with the hypothesis that genetic factors are partly responsible for the black–white difference in intelligence... the evidence that a statistically significant correlation is present confirms the genetic hypothesis". This statement was described by
Marcus Feldman as "nonsensical". In 2010
Earl B. Hunt summarized Lynn's research in this area along with that of
Tatu Vanhanen, that he is "highly critical of their empirical work, and even more so of their interpretations", but that they "do deserve credit for raising important questions in a way that has resulted in interesting and important findings". Lynn proposed the "cold winters theory" of the evolution of human intelligence, which postulates that intelligence evolved to greater degrees as an evolutionary adaptation to colder environments. According to this theory, cold environments produce a selective pressure for higher intelligence because they present cognitive demands not found in warmer environments, such as the need to find ways of keeping warm, and the stockpiling of food for winter.
James Flynn has criticized this theory as being inconsistent with the global distribution of IQ scores. If the theory were correct, the people of
Singapore, who originated primarily from China's southern Guangdong province, would possess a lower average IQ than the people of mainland China, when in fact the reverse is true. In 2012 Scott A. McGreal, writing for
Psychology Today, described it as a
just-so story, saying the theory fails to account for challenges specific to warmer environments, and also does not explain why hominids who evolved for millions of years in colder environments (such as
Neanderthals and
Homo erectus) did not also evolve similar intelligence. In
IQ and the Wealth of Nations (2002), Lynn and Vanhanen argued that differences in nations' per capita
gross domestic product (GDP) are partially caused by IQ differences, meaning that certain nations are wealthier in part,
because their citizens are more intelligent. K. Richardson wrote in the journal
Heredity that "an association between IQ and national wealth is hardly surprising, though its causal direction is the opposite of that assumed by L&V. But I would not take the 'evidence' presented in this book to serve arguments either way." to insecure estimates of the national IQ in the remaining 101 countries in the sample that did not have published IQ data. This was in addition to the highly unreliable GDP estimates for present-day developing countries In a book review for the
Journal of Economic Literature, economist Thomas Nechyba wrote: "Such sweeping conclusions based on relatively weak statistical evidence and dubious presumptions seem misguided at best and quite dangerous if taken seriously. It is therefore difficult to find much to recommend in this book." organises data on intelligence into ten population groups and (in the 2015 edition) covers over 500 published articles. Lynn's meta-analysis lists the average IQ scores of
East Asians (105),
Europeans (99), the
Inuit (91),
Southeast Asians and
indigenous peoples of the Americas each (87),
Pacific Islanders (85),
Middle Easterners,
South Asians and
North Africans each (84),
East and
West Africans (67),
Australian Aborigines (62) and
Bushmen and
Pygmies (54). Lynn has previously argued that nutrition is the best-supported environmental explanation for variation in the lower range, and a number of other environmental explanations have been advanced. In his 2011 book
The Chosen People, Lynn offers largely genetic explanations for Ashkenazi Jewish intelligence (generally estimated at 107–115 IQ).
Sex differences in intelligence Observing a correlation between brain size and measured IQ, Lynn postulated that men and women may have brains that are different in size in proportion with differences in body size. In 1994, Lynn formulated a
developmental theory of sex differences in intelligence, postulating that girls would have a developmental advantage over boys at the ages of 9 to 14, but that boys would continue to develop and increase in mean IQ relative to girls from the age of 15 onwards. In 2004, Lynn and Irwing conducted a meta-analysis of 57 studies from 14 countries, reporting a male advantage in IQ (measured via
Raven's Progressive Matrices) that begins to appear at the age of 15, eventually reaching an average of 5 IQ points at the ages of 20-29 and onwards. In a 2006 study of
Naglieri Nonverbal Ability Test results in 5-17 year olds, Johannes Rojahn and
Jack Naglieri reported findings that demonstrate a female advantage in the 10-13 age group and a male advantage in 15- and 16-year-olds. However, the authors conclude that the disparities were smaller than predicted by Lynn and too small to be of practical importance. In 2008, Lynn and Irwing proposed that since
working memory ability correlates highest with
g factor, researchers would have no choice but to accept greater male intelligence if differences on working memory tasks are found. As a result, a
neuroimaging study published by Schmidt et al. (2009) conducted an investigation into this proposal by measuring sex differences on an
n-back working memory task. The results found no sex difference in working memory capacity, thus contradicting the position put forward by Lynn and Irwing (2008). Roberto Colom and
Paul M. Thompson, writing in
The Wiley-Blackwell Handbook of Individual Differences, conclude based on the findings of Schmidt et al. and others that "there is no sex difference in working memory capacity". In a 2010 article about IQ in Italy, Lynn contended that IQs are highest in the north (103 in
Friuli-Venezia Giulia) and lowest in the south (89 in
Sicily) and are correlated with average incomes, stature, infant mortality, literacy and education. The lack of any actual IQ test data (as Lynn used PISA score data) among other methodological issues and Lynn's consequent conclusions were criticised. Other large surveys in Italy have found much smaller differences in educational achievement. Several subsequent studies based on the direct assessment of IQs failed to report significant differences among Italian regions. On the contrary, the results from the Southern half of the country (103) are sometimes higher than those from the North Central regions (100–101). In 2012 Lynn similarly claimed that southern Spaniards have lower IQs than northern Spaniards do and believes that this is because of Middle Eastern and North African genes in the South. In a 2015 article published in
Intelligence about the regional IQ differences in
Turkey, Lynn, Sakar and Cheng analysed the PISA scores of
NUTS-1 regions of the country and calculated the average IQ scores of said provinces, claiming there being a high correlation (r= .91) between the two metrics. The team took the average PISA score of UK as baseline to represent an IQ of 100. The paper concluded that the NUTS regions with the highest IQ average were
West Marmara (97.7),
East Marmara (97.4) and
Central Anatolia (97.3), meanwhile the regions with the lowest scores were made up by
Central East Anatolia (87.3) and
Southeast Anatolia (86.3), respectively. The article suggested multiple theories to explain regional IQ disparity, such as historical migration to wealthier Western coastal areas having a eugenic effect on intelligence, or economic growth being inhibited by the mountainous terrain in the East, causing a negative effect on IQ. The paper compared the results of the study to those of Italy and US, citing a gross regional variation.
The Global Bell Curve, 2008 The Global Bell Curve: Race, IQ and Inequality Worldwide is a book by Lynn, originally published
Washington Summit Publishers in 2008. The book's stated purpose is to determine whether the racial and socioeconomic differences in the United States in average IQ, as originally claimed by the 1994 book
The Bell Curve, also exist in other countries. Lynn's book claims that such differences exist in other countries, in addition to in the United States. It was reviewed favorably by researchers
J. Philippe Rushton,
Donald Templer in white nationalist publication
The Occidental Quarterly, and
Gerhard Meisenberg. A less favorable review of the book was written by
Wendy Johnson of the
University of Edinburgh, who wrote in
Intelligence, which had Lynn on its editorial board, that "...despite many possible statistical and psychometric quibbles, the data Lynn presents in this book are essentially correct. At the same time, despite Lynn's protestations to the contrary, these data do little or nothing to address the questions of why this is the case or whether the situation is inevitable or permanent. Like the other theorists he criticizes, Lynn confuses correlation with causation." ==Pioneer Fund==