Information about Flynn Effect
The Flynn effect is the rise of average Intelligence Quotient (IQ) test scores, an effect seen in most parts of the world, although at greatly varying rates. It is named after James R. Flynn, who did much to document it and promote awareness of its implications. This increase has been continuous and roughly linear from the earliest days of testing to the present. "Test scores are certainly going up all over the world, but
whether intelligence itself has risen remains controversial," psychologist Ulric Neisser wrote in an article in 1997 in The American Scientist.[1] The Flynn effect may have ended in some developed nations starting in the mid 1990s although other studies, such as Black Americans reduce the racial IQ gap: Evidence from standardization samples (Dickens, Flynn;2006), still show gain between 1972 and 2002.
The average rate of rise seems to be around three IQ points per decade. Because children attend school longer now and have become much more familiar with the testing of school-related material, one might expect the greatest gains to occur on such school content-related tests as vocabulary, arithmetic or general information. Just the opposite is the case: abilities such as these have experienced relatively small gains and even occasional declines over the years. The largest Flynn effects appear instead on culture reduced highly general intelligence factor loaded (g-loaded) tests such as Raven's Progressive Matrices. For example, Dutch conscripts gained 21 points in only 30 years, or 7 points per decade, between 1952 and 1982.[1]
Some studies focusing on the distribution of scores have found the Flynn effect to be primarily a phenomenon in the lower end of the distribution. Teasdale and Owen (1987), for example, found the effect primarily reduced the number of low-end scores, resulting in a pile up of moderately high scores, with no increase in very high scores.[2] However, Raven (2000) found that, as Flynn suggested, data reported by many previous researchers that had previously been interpreted as showing a decrease in many abilities with increasing age must be re-interpreted as showing that there has been a dramatic increase in these abilities with date of birth. On many tests this occurs at all levels of ability.[3] Two large samples of Spanish children were assessed with a 30-year gap. Comparison of the IQ distributions indicated that
Taken at face value, these changes are considered large by some. Ulric Neisser, who in 1995 headed an American Psychological Association task force writing a consensus statement on the state of intelligence research, estimates that if American children of 1932 could take an IQ test normed in 1997 their average IQ would have been only about 80.[1] In other words, half of the children in 1932 would be classified as having borderline mental retardation or worse in 1997. Looking at Ravens, Neisser estimates that if you extrapolate beyond the data, which shows a 21 point gain between 1952 and 1982, an even larger gain of 35 IQ points can be argued, however Arthur Jensen warns that extrapolating beyond the data leads to results such as an IQ of -1000 for Aristotle (even assuming he would have scored 200 in his day)[5]
Attempted explanations have included improved nutrition, a trend towards smaller families, better education, greater environmental complexity, and heterosis[6]. Another proposition is greater familiarity with multiple-choice questions and experience with brain-teaser IQ problems. [7]
Many studies find that children who do not attend school for one reason or another score lower on the tests than their regularly attending peers. In the 1960s, when some Virginia counties closed their public schools to avoid racial integration, compensatory private schooling was available only for white children. On average, the African-American children who received no formal education during that period fell back at a rate of about six IQ points per year. Length of average schooling has steadily increased. One problem with this explanation is that if comparing older and more recent subjects with similar educational levels, then the IQ gains appear almost undiminished in each such group considered individually.[1] Mathematics has been proposed as particularly important.[8]
Another explanation is an increased familiarity of the general populace with tests and testing. For example, children who take the very same IQ test a second time usually gain 5 or 6 points by doing so. However, this seems to set an upper limit on the effects of test sophistication. One problem with this explanation and other related to the schooling is, as noted above, that those subsets one would expect to be affected the most show the smallest increases.[1]
Another theory is that many parents are now interested in their children's intellectual development and are probably doing more to encourage it than they did in the past. Early intervention programs have shown mixed results. Some preschool (age 3-4) intervention programs like "Head Start" do not produce lasting changes in IQ, although they do confer other important benefits. The "Abecedarian Project", an all-day program that provided various forms of environmental enrichment to children from infancy onward showed IQ gains that did not diminish over time; the IQ difference between the groups was still present at age twelve. This very intensive intervention resulted in a gain of five IQ points, and not all such projects have been successful.[1] Also, such IQ gains can diminish until the age of 18.[9] Several other studies have also found lasting cognitive gains.[10]
Still another is that the general environment is today much more complex and stimulating. One of the most striking 20th-century change in the human intellectual environment has come from the increase in exposure to many types of visual media. From pictures on the wall to movies to television to video games to computers, each successive generation has been exposed to far richer optical displays than the one before and may have become more adept at visual analysis. This would explain why tests like the Raven's have shown the greatest increases, since they depend on such analysis. This explanation may imply that IQ tests do not necessarily measure a general intelligence factor, especially not Raven's as often argued, but instead may measure different forms of intelligence that are developed by different experiences. An increase only in particular form(s) of intelligence would explain why the Flynn effect has not caused a "cultural renaissance too great to be overlooked."[1]
Improved nutrition is another explanation. Today's average adult from an industrialized nation stands much taller than the comparable adult of a century ago. That increase in stature, almost certainly the result general improvements in nutrition and health, has come at a rate of more than a centimeter per decade. Available data suggest that these gains have been accompanied by analogous increases in head size, and presumably by an increase in the average size of the brain. One problem with this, and other explanations arguing that the IQ gains reflect real gains in general intelligence, is that if all of the gains are real, then this would imply changes in average mental ability too great to seem plausible.[1] A 2005 study presented data supporting the nutrition hypothesis, which predicts that gains in IQ will predominantly occur at the low end of the distribution where nutritional deprivation is most severe.[4]
Possibly related to the Flynn effect is change in cranial vault size and shape during the last 150 years in the US. These changes must occur by early childhood because of the early development of the vault.[11]
Flynn earlier argued that the very large increase indicates that IQ tests do not measure intelligence well but only a minor sort of "abstract problem-solving ability" with little practical significance.[1]
Dickens and Flynn in 2001 presented a model for resolving several contradictory findings regarding IQ. They argue that the measure "heritability" includes both a direct effect of the genotype on IQ and also indirect effects where the genotype changes the environment, in turn affecting IQ. That is, those with a higher IQ tend to seek out stimulating environments that further increase IQ. The direct effect can initially have been very small but feedback loops can create large differences in IQ. In their model an environmental stimulus can have a very large effect on IQ, even in adults, but this effect also decays over time unless the stimulus continues (the model could be adapted to include possible factors, like nutrition in early childhood, that may cause permanent effects). The Flynn effect can be explained by a generally more stimulating environment for all people. The authors suggest that programs aiming to increase IQ would be most likely to produce long-term IQ gains if they taught children how to replicate outside the program the kinds of cognitively demanding experiences that produce IQ gains while they are in the program and motivate them to persist in that replication long after they have left the program.[12][13] However if the Flynn Effect is caused by intellectual stimulation, this may suggest that the Flynn Effect is unrelated to g because according to Jensen "the preponderance of evidence argues that variance in the level of g is not a psychologically manipulable variable, but rather a biological phenomenon under the control both of the genes and of those external physical variables that affect the physiological and biochemical functioning of the central nervous system, which mediates the behavioral manifestations of g[14]...Anything less than very early and intensive intervention, including medical and nutritional advances, during the preschool years (and also prenatally) is probably inadequate to cause a lasting increase in the child's level of g."[15] However, Dickens and Flynn's paper, which was written after Jensen's book, disputes Jensen's claims, for example arguing that using Jensen's methodology the Flynn effect is found to be substantially due to genetic improvements, an extremely unlikely cause. Their theory explains such contradictions.
Some researchers, such as J. Phillipe Rushton[16] argue the Flynn effect largely has not changed the general intelligence factor (g), which would mean practical significance of the effect would be limited. More recent studies have found that g has improved substantially[17][18]
Studies that make use of multigroup confirmatory factor analysis test for "measurement invariance." Where tenable, invariance demonstrates that group differences exist in the latent constructs the tests contain and not, for example, as a result of measurement artifacts or cultural bias. Wicherts et al. (2004) found evidence from five data sets that IQ scores are not measurement invariant over time, and thus "the gains cannot be explained solely by increases at the level of the latent variables (common factors), which IQ tests purport to measure". In other words, according to this study, some of the inter-generational difference in IQ is attributable to bias or other artifacts, and not real gains in general intelligence or higher-order ability factors.[19]
A 2003 study looking at the Flynn effect in Kenya between 1984 and 1998 found that the increase was best explained by parents' literacy, family structure, and children's nutrition and health.[20]
A 2006 study from Brazil looked at data from testing children in 1930 and 2002-2004, the largest gap ever considered. The results are consistent with both the cognitive stimulation and the nutritional hypotheses.[21]
In the end a number of varied phenomena may be contributing to the Flynn effect.
The Flynn effect may have ended in some developed nations starting in the mid 1990s. Teasdale & Owen (2005) "report intelligence test results from over 500,000 young Danish men, tested between 1959 and 2004, showing that performance peaked in the late 1990s, and has since declined moderately to pre-1991 levels." They speculate that "a contributing factor in this recent fall could be a simultaneous decline in proportions of students entering 3-year advanced-level school programs for 16–18 year olds."[23]
In 2004, Jon Martin Sundet of the University of Oslo and colleagues published an article documenting scores on intelligence tests given to Norwegian conscripts between the 1950s and 2002, showing that the increase in scores of general intelligence stopped after the mid-1990s and in numerical reasoning subtests, declined.[24]
Some have claimed that the Flynn effect was masking a dysgenic decline in human reproduction and that in developed countries the only direction that IQ scores will now move is downwards. However, even if there is a decline, then this may have other causes than dysgenics. Genetic changes usually happen relatively slowly. For example, the Flynn effect has been too rapid for a genetic explanation.[25] Researchers have warned that constantly greater exposure to industrial chemicals shown to damage the nervous system, especially in children, in industrialized nations may be responsible for a "silent pandemic" of brain development disorders.[1]
Also, if the Flynn effect has ended for the majority, it may still continue for minorities, especially for groups like immigrants where many may have received poor nutrition during early childhood. For example, William T. Dickens and James R. Flynn write in their 2006 paper that Black Americans reduce the racial IQ gap: Evidence from standardization samples that blacks have gained 5 or 6 IQ points on non-Hispanic whites between 1972 and 2002. Gains have been fairly uniform across the entire range of black cognitive ability.[26]
Heterosis is a term used in genetics and selective breeding. The term heterosis, also known as hybrid vigor, hybrid vigour, or outbreeding enhancement
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The rise
IQ tests are re-normalized periodically, such that the average score is reset to 100. The revised versions are standardized on new samples and scored with respect to those samples alone, so the only way to compare the difficulty of two versions of a test is to conduct a separate study in which the same subjects take both versions.[1]The average rate of rise seems to be around three IQ points per decade. Because children attend school longer now and have become much more familiar with the testing of school-related material, one might expect the greatest gains to occur on such school content-related tests as vocabulary, arithmetic or general information. Just the opposite is the case: abilities such as these have experienced relatively small gains and even occasional declines over the years. The largest Flynn effects appear instead on culture reduced highly general intelligence factor loaded (g-loaded) tests such as Raven's Progressive Matrices. For example, Dutch conscripts gained 21 points in only 30 years, or 7 points per decade, between 1952 and 1982.[1]
Some studies focusing on the distribution of scores have found the Flynn effect to be primarily a phenomenon in the lower end of the distribution. Teasdale and Owen (1987), for example, found the effect primarily reduced the number of low-end scores, resulting in a pile up of moderately high scores, with no increase in very high scores.[2] However, Raven (2000) found that, as Flynn suggested, data reported by many previous researchers that had previously been interpreted as showing a decrease in many abilities with increasing age must be re-interpreted as showing that there has been a dramatic increase in these abilities with date of birth. On many tests this occurs at all levels of ability.[3] Two large samples of Spanish children were assessed with a 30-year gap. Comparison of the IQ distributions indicated that
- the mean IQ had increased by 9.7 points (the Flynn effect),
- the gains were concentrated in the lower half of the distribution and negligible in the top half, and
- the gains gradually decreased from low to high IQ.[4]
Taken at face value, these changes are considered large by some. Ulric Neisser, who in 1995 headed an American Psychological Association task force writing a consensus statement on the state of intelligence research, estimates that if American children of 1932 could take an IQ test normed in 1997 their average IQ would have been only about 80.[1] In other words, half of the children in 1932 would be classified as having borderline mental retardation or worse in 1997. Looking at Ravens, Neisser estimates that if you extrapolate beyond the data, which shows a 21 point gain between 1952 and 1982, an even larger gain of 35 IQ points can be argued, however Arthur Jensen warns that extrapolating beyond the data leads to results such as an IQ of -1000 for Aristotle (even assuming he would have scored 200 in his day)[5]
Proposed explanations
- See also:
Attempted explanations have included improved nutrition, a trend towards smaller families, better education, greater environmental complexity, and heterosis[6]. Another proposition is greater familiarity with multiple-choice questions and experience with brain-teaser IQ problems. [7]
Many studies find that children who do not attend school for one reason or another score lower on the tests than their regularly attending peers. In the 1960s, when some Virginia counties closed their public schools to avoid racial integration, compensatory private schooling was available only for white children. On average, the African-American children who received no formal education during that period fell back at a rate of about six IQ points per year. Length of average schooling has steadily increased. One problem with this explanation is that if comparing older and more recent subjects with similar educational levels, then the IQ gains appear almost undiminished in each such group considered individually.[1] Mathematics has been proposed as particularly important.[8]
Another explanation is an increased familiarity of the general populace with tests and testing. For example, children who take the very same IQ test a second time usually gain 5 or 6 points by doing so. However, this seems to set an upper limit on the effects of test sophistication. One problem with this explanation and other related to the schooling is, as noted above, that those subsets one would expect to be affected the most show the smallest increases.[1]
Another theory is that many parents are now interested in their children's intellectual development and are probably doing more to encourage it than they did in the past. Early intervention programs have shown mixed results. Some preschool (age 3-4) intervention programs like "Head Start" do not produce lasting changes in IQ, although they do confer other important benefits. The "Abecedarian Project", an all-day program that provided various forms of environmental enrichment to children from infancy onward showed IQ gains that did not diminish over time; the IQ difference between the groups was still present at age twelve. This very intensive intervention resulted in a gain of five IQ points, and not all such projects have been successful.[1] Also, such IQ gains can diminish until the age of 18.[9] Several other studies have also found lasting cognitive gains.[10]
Still another is that the general environment is today much more complex and stimulating. One of the most striking 20th-century change in the human intellectual environment has come from the increase in exposure to many types of visual media. From pictures on the wall to movies to television to video games to computers, each successive generation has been exposed to far richer optical displays than the one before and may have become more adept at visual analysis. This would explain why tests like the Raven's have shown the greatest increases, since they depend on such analysis. This explanation may imply that IQ tests do not necessarily measure a general intelligence factor, especially not Raven's as often argued, but instead may measure different forms of intelligence that are developed by different experiences. An increase only in particular form(s) of intelligence would explain why the Flynn effect has not caused a "cultural renaissance too great to be overlooked."[1]
Improved nutrition is another explanation. Today's average adult from an industrialized nation stands much taller than the comparable adult of a century ago. That increase in stature, almost certainly the result general improvements in nutrition and health, has come at a rate of more than a centimeter per decade. Available data suggest that these gains have been accompanied by analogous increases in head size, and presumably by an increase in the average size of the brain. One problem with this, and other explanations arguing that the IQ gains reflect real gains in general intelligence, is that if all of the gains are real, then this would imply changes in average mental ability too great to seem plausible.[1] A 2005 study presented data supporting the nutrition hypothesis, which predicts that gains in IQ will predominantly occur at the low end of the distribution where nutritional deprivation is most severe.[4]
Possibly related to the Flynn effect is change in cranial vault size and shape during the last 150 years in the US. These changes must occur by early childhood because of the early development of the vault.[11]
Flynn earlier argued that the very large increase indicates that IQ tests do not measure intelligence well but only a minor sort of "abstract problem-solving ability" with little practical significance.[1]
Dickens and Flynn in 2001 presented a model for resolving several contradictory findings regarding IQ. They argue that the measure "heritability" includes both a direct effect of the genotype on IQ and also indirect effects where the genotype changes the environment, in turn affecting IQ. That is, those with a higher IQ tend to seek out stimulating environments that further increase IQ. The direct effect can initially have been very small but feedback loops can create large differences in IQ. In their model an environmental stimulus can have a very large effect on IQ, even in adults, but this effect also decays over time unless the stimulus continues (the model could be adapted to include possible factors, like nutrition in early childhood, that may cause permanent effects). The Flynn effect can be explained by a generally more stimulating environment for all people. The authors suggest that programs aiming to increase IQ would be most likely to produce long-term IQ gains if they taught children how to replicate outside the program the kinds of cognitively demanding experiences that produce IQ gains while they are in the program and motivate them to persist in that replication long after they have left the program.[12][13] However if the Flynn Effect is caused by intellectual stimulation, this may suggest that the Flynn Effect is unrelated to g because according to Jensen "the preponderance of evidence argues that variance in the level of g is not a psychologically manipulable variable, but rather a biological phenomenon under the control both of the genes and of those external physical variables that affect the physiological and biochemical functioning of the central nervous system, which mediates the behavioral manifestations of g[14]...Anything less than very early and intensive intervention, including medical and nutritional advances, during the preschool years (and also prenatally) is probably inadequate to cause a lasting increase in the child's level of g."[15] However, Dickens and Flynn's paper, which was written after Jensen's book, disputes Jensen's claims, for example arguing that using Jensen's methodology the Flynn effect is found to be substantially due to genetic improvements, an extremely unlikely cause. Their theory explains such contradictions.
Some researchers, such as J. Phillipe Rushton[16] argue the Flynn effect largely has not changed the general intelligence factor (g), which would mean practical significance of the effect would be limited. More recent studies have found that g has improved substantially[17][18]
Studies that make use of multigroup confirmatory factor analysis test for "measurement invariance." Where tenable, invariance demonstrates that group differences exist in the latent constructs the tests contain and not, for example, as a result of measurement artifacts or cultural bias. Wicherts et al. (2004) found evidence from five data sets that IQ scores are not measurement invariant over time, and thus "the gains cannot be explained solely by increases at the level of the latent variables (common factors), which IQ tests purport to measure". In other words, according to this study, some of the inter-generational difference in IQ is attributable to bias or other artifacts, and not real gains in general intelligence or higher-order ability factors.[19]
A 2003 study looking at the Flynn effect in Kenya between 1984 and 1998 found that the increase was best explained by parents' literacy, family structure, and children's nutrition and health.[20]
A 2006 study from Brazil looked at data from testing children in 1930 and 2002-2004, the largest gap ever considered. The results are consistent with both the cognitive stimulation and the nutritional hypotheses.[21]
In the end a number of varied phenomena may be contributing to the Flynn effect.
Has progression ended?
)
William T. Dickens and James R. Flynn write that blacks have gained 5 or 6 IQ points on non-Hispanic whites between 1972 and 2002. This graph shows the gains for various tests.[22]
In 2004, Jon Martin Sundet of the University of Oslo and colleagues published an article documenting scores on intelligence tests given to Norwegian conscripts between the 1950s and 2002, showing that the increase in scores of general intelligence stopped after the mid-1990s and in numerical reasoning subtests, declined.[24]
Some have claimed that the Flynn effect was masking a dysgenic decline in human reproduction and that in developed countries the only direction that IQ scores will now move is downwards. However, even if there is a decline, then this may have other causes than dysgenics. Genetic changes usually happen relatively slowly. For example, the Flynn effect has been too rapid for a genetic explanation.[25] Researchers have warned that constantly greater exposure to industrial chemicals shown to damage the nervous system, especially in children, in industrialized nations may be responsible for a "silent pandemic" of brain development disorders.[1]
Also, if the Flynn effect has ended for the majority, it may still continue for minorities, especially for groups like immigrants where many may have received poor nutrition during early childhood. For example, William T. Dickens and James R. Flynn write in their 2006 paper that Black Americans reduce the racial IQ gap: Evidence from standardization samples that blacks have gained 5 or 6 IQ points on non-Hispanic whites between 1972 and 2002. Gains have been fairly uniform across the entire range of black cognitive ability.[26]
References
1. ^ Rising Scores on Intelligence Test Neisser, U. (1997). American Scientist, 85, 440-447.
2. ^ Teasdale, Thomas W., and David R. Owen. (1987). ‘National secular trends in intelligence and education: a twenty year cross-sectional study’, Nature, 325, 119-21.
3. ^ Raven, J. (2000). The Raven’s Progressive Matrices: Change and stability over culture and time. Cognitive Psychology, 41, 1-48.
4. ^ Colom, R., Lluis-Font, J.M., and Andrés-Pueyo, A. (2005). "The generational intelligence gains are caused by decreasing variance in the lower half of the distribution: Supporting evidence for the nutrition hypothesis". Intelligence 33: 83-91.
5. ^ The g factor by Aurthur Jensen pg 328
6. ^ Mingroni, M.A. (2004). "The secular rise in IQ: Giving heterosis a closer look". Intelligence 32: 65–83.
7. ^ (Ulric Neisser et al 1998) [2]
8. ^ Rising mean IQ: Cognitive demand of mathematics education for young children, population exposure to formal schooling, and the neurobiology of the prefrontal cortex Clancy Blair, David Gamson, Steven Thorne, David Baker. Intelligence 33 (2005) 93–106
9. ^ Plomin, R., DeFries, J. C., Craig, I. W., & McGuffin, P. (2003). Behavioral genetics in the postgenomic era.
10. ^ Contributions of early childhood education to age-14 performance Cathy Wylie, Edith Hodgen, Hilary Ferral, and Jean Thompson. NEW ZEALAND COUNCIL FOR EDUCATIONAL RESEARCH TE RÜNANGA O AOTEAROA MÖ TE RANGAHAU I TE MÄTAURANGA WELLINGTON 2006
11. ^ "Changes in vault dimensions must occur by early childhood because of the early development of the vault." Secular change in craniofacial morphology "During the 125 years under consideration, cranial vaults have become markedly higher, somewhat narrower, with narrower faces. The changes in cranial morphology are probably in large part due to changes in growth at the cranial base due to improved environmental conditions. The changes are likely a combination of phenotypic plasticity and genetic changes over this period." Cranial change in Americans: 1850-1975.
12. ^ William T. Dickens and James R. Flynn, Heritability Estimates Versus Large Environmental Effects:The IQ Paradox Resolved, Psychological Review 2001. Vol. 108, No. 2. 346-369.
13. ^ William T. Dickens and James R. Flynn, "The IQ Paradox: Still Resolved," Psychological Review 109, no. 4 (2002).
14. ^ The g factor by Arthur Jensen pg 336
15. ^ The g factor by Aurthur Jensen pg 344
16. ^ Rushton, J. P. (1999). "Secular Gains in IQ Not Related to the g Factor and Inbreeding Depression--Unlike Black-White Differences: A Reply to Flynn". Personality and Individual Difference 26: 381-389. doi:10.1016/S0191-8869(98)00148-2.
17. ^ Are cognitive differences between immigrant and majority groups diminishing?TE NIJENHUIS Jan ; DE JONG Mart-Jan ; EVERS Arne ; VAN DER FLIER Henk ; European journal of personality (Eur. j. pers.) 2004, vol. 18, no5, pp. 405-434
18. ^ Secular Gains in Fluid Intelligence: Evidence from the Culture-Fair Intelligence Test Roberto Colom and Oscar Garcia-Lopez, Journal of Biosocial Science (2003), 35: 33-39 Cambridge University Press
19. ^ Wicherts, J.M., Dolan, C.V., Hessen, D.J., Oosterveld, P., Baal, G.C.M. van, Boomsma, D.I., & Span, M.M. (2004). "Are intelligence tests measurement invariant over time? Investigating the nature of the Flynn effect". Intelligence 32: 509–537. (links to PDF file)
20. ^ Iq on the rise: The Flynn Effect in Rural Kenyan Children amara C. Daley, Shannon E. Whaley,Marian D. Sigman, Michael P. Espinosa, and Charlotte Neumann. Psychological Science 14 (3), 215–219.
21. ^ Generational changes on the draw-a-man test: a comparison of brazilian urban and rural children tested in 1930, 2002 and 2004 Colom R, Flores-Mendoza CE, Abad FJ. J Biosoc Sci. 2007 Jan;39(1):79-89. Epub 2006 Jan 27.
22. ^ Black Americans reduce the racial IQ gap: Evidence from standardization samples William T. Dickens and James R. Flynn. Oct. 2006
23. ^ * Teasdale, Thomas W., and David R. Owen. (2005). "A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse." Personality and Individual Differences. 39(4):837-843.
24. ^ The end of the Flynn Effect. A study of secular trends in mean intelligence scores of Norwegian conscripts during half a century.. Retrieved on August 6, 2006.
25. ^ Rising mean IQ: Cognitive demand of mathematics education for young children, population exposure to formal schooling, and the neurobiology of the prefrontal cortex Clancy Blair, David Gamson, Steven Thorne, David Baker. Intelligence 33 (2005) 93–106
26. ^ Black Americans reduce the racial IQ gap: Evidence from standardization samples William T. Dickens and James R. Flynn. Oct. 2006
2. ^ Teasdale, Thomas W., and David R. Owen. (1987). ‘National secular trends in intelligence and education: a twenty year cross-sectional study’, Nature, 325, 119-21.
3. ^ Raven, J. (2000). The Raven’s Progressive Matrices: Change and stability over culture and time. Cognitive Psychology, 41, 1-48.
4. ^ Colom, R., Lluis-Font, J.M., and Andrés-Pueyo, A. (2005). "The generational intelligence gains are caused by decreasing variance in the lower half of the distribution: Supporting evidence for the nutrition hypothesis". Intelligence 33: 83-91.
5. ^ The g factor by Aurthur Jensen pg 328
6. ^ Mingroni, M.A. (2004). "The secular rise in IQ: Giving heterosis a closer look". Intelligence 32: 65–83.
7. ^ (Ulric Neisser et al 1998) [2]
8. ^ Rising mean IQ: Cognitive demand of mathematics education for young children, population exposure to formal schooling, and the neurobiology of the prefrontal cortex Clancy Blair, David Gamson, Steven Thorne, David Baker. Intelligence 33 (2005) 93–106
9. ^ Plomin, R., DeFries, J. C., Craig, I. W., & McGuffin, P. (2003). Behavioral genetics in the postgenomic era.
10. ^ Contributions of early childhood education to age-14 performance Cathy Wylie, Edith Hodgen, Hilary Ferral, and Jean Thompson. NEW ZEALAND COUNCIL FOR EDUCATIONAL RESEARCH TE RÜNANGA O AOTEAROA MÖ TE RANGAHAU I TE MÄTAURANGA WELLINGTON 2006
11. ^ "Changes in vault dimensions must occur by early childhood because of the early development of the vault." Secular change in craniofacial morphology "During the 125 years under consideration, cranial vaults have become markedly higher, somewhat narrower, with narrower faces. The changes in cranial morphology are probably in large part due to changes in growth at the cranial base due to improved environmental conditions. The changes are likely a combination of phenotypic plasticity and genetic changes over this period." Cranial change in Americans: 1850-1975.
12. ^ William T. Dickens and James R. Flynn, Heritability Estimates Versus Large Environmental Effects:The IQ Paradox Resolved, Psychological Review 2001. Vol. 108, No. 2. 346-369.
13. ^ William T. Dickens and James R. Flynn, "The IQ Paradox: Still Resolved," Psychological Review 109, no. 4 (2002).
14. ^ The g factor by Arthur Jensen pg 336
15. ^ The g factor by Aurthur Jensen pg 344
16. ^ Rushton, J. P. (1999). "Secular Gains in IQ Not Related to the g Factor and Inbreeding Depression--Unlike Black-White Differences: A Reply to Flynn". Personality and Individual Difference 26: 381-389. doi:10.1016/S0191-8869(98)00148-2.
17. ^ Are cognitive differences between immigrant and majority groups diminishing?TE NIJENHUIS Jan ; DE JONG Mart-Jan ; EVERS Arne ; VAN DER FLIER Henk ; European journal of personality (Eur. j. pers.) 2004, vol. 18, no5, pp. 405-434
18. ^ Secular Gains in Fluid Intelligence: Evidence from the Culture-Fair Intelligence Test Roberto Colom and Oscar Garcia-Lopez, Journal of Biosocial Science (2003), 35: 33-39 Cambridge University Press
19. ^ Wicherts, J.M., Dolan, C.V., Hessen, D.J., Oosterveld, P., Baal, G.C.M. van, Boomsma, D.I., & Span, M.M. (2004). "Are intelligence tests measurement invariant over time? Investigating the nature of the Flynn effect". Intelligence 32: 509–537. (links to PDF file)
20. ^ Iq on the rise: The Flynn Effect in Rural Kenyan Children amara C. Daley, Shannon E. Whaley,Marian D. Sigman, Michael P. Espinosa, and Charlotte Neumann. Psychological Science 14 (3), 215–219.
21. ^ Generational changes on the draw-a-man test: a comparison of brazilian urban and rural children tested in 1930, 2002 and 2004 Colom R, Flores-Mendoza CE, Abad FJ. J Biosoc Sci. 2007 Jan;39(1):79-89. Epub 2006 Jan 27.
22. ^ Black Americans reduce the racial IQ gap: Evidence from standardization samples William T. Dickens and James R. Flynn. Oct. 2006
23. ^ * Teasdale, Thomas W., and David R. Owen. (2005). "A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse." Personality and Individual Differences. 39(4):837-843.
24. ^ The end of the Flynn Effect. A study of secular trends in mean intelligence scores of Norwegian conscripts during half a century.. Retrieved on August 6, 2006.
25. ^ Rising mean IQ: Cognitive demand of mathematics education for young children, population exposure to formal schooling, and the neurobiology of the prefrontal cortex Clancy Blair, David Gamson, Steven Thorne, David Baker. Intelligence 33 (2005) 93–106
26. ^ Black Americans reduce the racial IQ gap: Evidence from standardization samples William T. Dickens and James R. Flynn. Oct. 2006
Further reading
- Flynn, J. R. (1984). The mean IQ of Americans: Massive gains 1932 to 1978. Psychological Bulletin, 95, 29-51.
- Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Bulletin, 101, 171-191.
- Flynn, J. R., What is Intelligence?: Beyond the Flynn Effect, Cambridge University Press (2007).
- Ulric Neisser et al.: The Rising Curve: Long-Term Gains in IQ and Related Measures. American Psychological Association (APA), 1998, ISBN 1-55798-503-0.
See also
External links
- The Flynn Effect by Indiana University.
- Marguerite Holloway, Flynn's effect, Scientific American, January 1999; online edition
- Increasing intelligence: the Flynn effect
- Flynn biography
- "An Explanation for the Flynn Effect"
- "Heritability Estimates Versus Large Environmental Effects: The IQ Paradox Resolved" - article by Dickens and Flynn
- Heredity, Environment, and Cranial Form: A Reanalysis of Boas’s Immigrant Data
- Did Boas get it right or wrong?
- "Dome Improvement" (Wired article)
| Race and intelligence |
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Research: Test data, Explanations, and Interpretations Controversies: Utility and Potential for bias History | Media portrayal | References |
intelligence quotient or IQ is a score derived from one of several different standardized tests attempting to measure intelligence. IQ tests are used as predictors of educational achievement. People with low IQ scores are sometimes placed in special-needs education.
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James Robert Flynn (also Jim Flynn, born 1934) is an intelligence researcher and Emeritus Professor of Political Studies at the University of Otago in Dunedin, New Zealand, known for his discovery of the Flynn effect, the continued year-on-year rise of IQ scores in all parts of the
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This article or section needs sources or references that appear in reliable, third-party publications. Alone, primary sources and sources affiliated with the subject of this article are not sufficient for an accurate encyclopedia article.
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20th century - 21st century
1960s 1970s 1980s - 1990s - 2000s 2010s 2020s
1994 1995 1996 - 1997 - 1998 1999 2000
Year 1997 (MCMXCVII
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1960s 1970s 1980s - 1990s - 2000s 2010s 2020s
1994 1995 1996 - 1997 - 1998 1999 2000
Year 1997 (MCMXCVII
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standardization or standardisation can have several meanings depending on its context. Common use of the word standard implies that it is a universally agreed-upon set of guidelines for interoperability.
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A vocabulary is a set of words known to a person or other entity, or that are part of a specific language.
The vocabulary of a person is defined either as the set of all words that are understood by that person or the set of all words likely to be used by that person when
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The vocabulary of a person is defined either as the set of all words that are understood by that person or the set of all words likely to be used by that person when
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Arithmetic or arithmetics (from the Greek word αριθμός = number) is the oldest and most elementary branch of mathematics, used by almost everyone, for tasks ranging from simple day-to-day counting to advanced science and business
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general intelligence factor (abbreviated g) is a controversial construct used in the field of psychology (see also psychometrics) to quantify what is common to the scores of all intelligence tests.
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Raven's Progressive Matrices (often referred to simply as Raven's Matrices) are multiple choice tests of abstract reasoning, originally developed by Dr John C. Raven in 1938.
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This article or section needs sources or references that appear in reliable, third-party publications. Alone, primary sources and sources affiliated with the subject of this article are not sufficient for an accurate encyclopedia article.
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American Psychological Association
Logo of the APA
Formation 1892
Headquarters Washington, D.C., United States
Membership 150,000 members
President Sharon Stephens Brehm, PhD
Website [1]
The American Psychological Association
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Logo of the APA
Formation 1892
Headquarters Washington, D.C., United States
Membership 150,000 members
President Sharon Stephens Brehm, PhD
Website [1]
The American Psychological Association
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MeSH D008607
Mental retardation
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“Half-wit” redirects here. For the episode of House, see Half-Wit (House episode).
Mental retardation
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extrapolation is the process of constructing new data points outside a discrete set of known data points. It is similar to the process of interpolation, which constructs new points between known points, but its results are often less meaningful, and are subject to greater
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Arthur Jensen (born August 24 1923) is a Professor Emeritus of educational psychology at the University of California, Berkeley.[1] Jensen is known for his work in psychometrics and differential psychology, which is concerned with how and why individuals differ
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Aristotle (Greek: Ἀριστοτέλης Aristotélēs) (384 BC – 322 BC) was a Greek philosopher, a student of Plato and teacher of Alexander the Great.
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Not to be confused with Heterotic string theory.
Heterosis is a term used in genetics and selective breeding. The term heterosis, also known as hybrid vigor, hybrid vigour, or outbreeding enhancement
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Multiple choice questions (MCQ) or items are a form of assessment item for which respondents are asked to select one or more of the choices from a list. This type of question is used in education testing, in elections (choose between multiple candidates, parties, or policies), in
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Please help recruit one or [ improve this article] yourself. See the talk page for details.
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In genetics, heritability is the proportion of phenotypic variation in a population that is attributable to genetic variation among individuals. Variation among individuals may be due to genetic and/or environmental factors.
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Genotype describes the genetic constitution of an individual, that is the specific allelic makeup of an individual, usually with reference to a specific character under consideration [1].
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John Philippe (Phil) Rushton (born December 3, 1943) is a psychology professor at the University of Western Ontario, Canada, known for his work on intelligence and racial differences, such as his book Race, Evolution and Behavior. He is the current head of the Pioneer Fund.
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general intelligence factor (abbreviated g) is a controversial construct used in the field of psychology (see also psychometrics) to quantify what is common to the scores of all intelligence tests.
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general intelligence factor (abbreviated g) is a controversial construct used in the field of psychology (see also psychometrics) to quantify what is common to the scores of all intelligence tests.
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Motto
none
(Royal motto: Guds hjælp, Folkets kærlighed, Danmarks styrke
"The Help of God, the Love of the People, the Strength of Denmark" )
Anthem
Der er et yndigt land (national)
Kong Christian
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none
(Royal motto: Guds hjælp, Folkets kærlighed, Danmarks styrke
"The Help of God, the Love of the People, the Strength of Denmark" )
Anthem
Der er et yndigt land (national)
Kong Christian
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University of Oslo (Norwegian: Universitetet i Oslo, Latin: Universitas Osloensis) was founded in 1811 as Universitas Regia Fredericiana (the Royal Frederick University
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Motto
Anthem
Ja, vi elsker
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Royal: Alt for Norge ("Everything for Norway")
1814 Eidsvoll oath: Enige og tro til Dovre faller
("United and faithful until the mountains of Dovre crumble")
1814 Eidsvoll oath: Enige og tro til Dovre faller
("United and faithful until the mountains of Dovre crumble")
Anthem
Ja, vi elsker
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In population genetics, dysgenic is a now-obsolete and abandoned term describing an alleged progressive evolutionary "weakening" of a population of organisms relative to their environment, often due to relaxation of natural selection or the occurrence of negative selection.
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digital object identifier (or DOI) is a permanent identifier given to a document, which is not related to its current location. A typical use of a DOI is to give a scientific paper or article a unique identifying number that can be used by anyone to locate details of the paper, and
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Intelligence is a property of mind that encompasses many related abilities, such as the capacities to reason, to plan, to solve problems, to think abstractly, to comprehend ideas, to use language, and to learn. There are several ways to define intelligence.
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In population genetics, dysgenic is a now-obsolete and abandoned term describing an alleged progressive evolutionary "weakening" of a population of organisms relative to their environment, often due to relaxation of natural selection or the occurrence of negative selection.
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Herod_Archelaus
