Posted on 05/12/2009 4:04:03 PM PDT by GOPGuide
Sowell is wrong on the science.
IQ is 75% genetic.
An inherited trait like intelligence or height needs a sufficient environment in which to achieve that maximum. For example, Japanese are stereotypically considered short, yet many young Japanese are significantly taller than their parents. Did their genes change? Of course not, even though genetics play a large role in height. Their diet did. The Japanese diet became richer in protein and calories so that young Japanese are now more likely to reach their maximum potential where they once did not.
The Flynn effect is not measuring an increase in “g”.
The effect is measuring something other than intelligence, what it is measuring isn’t known but real IQ gains are not it.
Looks like it’s talking about IQ to me. What’s “real IQ” and why isn’t the Flynn Effect measuring it?
Research shows that IQ gains have been mixed for different countries. In general, countries have seen generational increases between 5 and 25 points. The largest gains appear to occur on tests that measure fluid intelligence (Gf) rather than crystallized intelligence (Gc).
What makes you think they aren't talking about IQ and general intelligence?
Please note that if you want to argue that Flynn is not really talking about IQ and general intelligence and believe Flynn that, “IQ tests do not measure intelligence but rather correlate with a weak causal link to intelligence,” that then begs the question of how one can reliably measure the IQ or general intelligence of anyone if IQ tests are an unreliable measure.
The increases are NOT on real IQ.
And psychologists can tell the difference between fluid g and crystalized g because of more sophisticated tests.
If a mother and father each have an IQ of 75, it isn’t likely that their kids will have IQs of 150.
“If intelligence is 75% inherited, then how do you explain the Flynn Effect? Do you think people are evolving at 3 IQ points per decade?”
1. Note that in relation to the Flynn effect most or all of the gains were domain specific. For instance, major improvements seen on The Wechsler Intelligence Scale for Children (WISC) are on areas involving visual logic. With tv, & electronic gadgetry people have much more practice at decoding images quickly than in the past. Subtests involving general knowledge, arithmetic, and vocabulary have only seen small gains. In some cases, nutrition could be a factor in some cases. This seems to be the case in That would explain the huge gains in Korea and Japan post WWII.
2. Given most of the gains have been only on some tests it is doubted that FE gains have been g (general intelligence factor) loaded, since g loaded gains would necessarily boost all cognitive tasks.
3. Reaction time tests measure g, yet chronometric measures have not been shown to change over decades.
4. Flynn does not believe that the FE will narrow the B-W IQ gap. Some environmentalists have argued that it will, but no evidence has surfaced to show that after decades of rise, the FE has actually narrowed the gap.
5. In some countries the Flynn effect has stoppped and in Scandinavia there has been recent slight reversal.
6. In terms of whether tests measure IQ, the thing is that the tests have external validity in terms of the general intelligence factor ‘g’ which is obtained from factor analysis. Today, virtually all intelligence research (worldwide) is about g.
7. There are a number of neurological correlates with ‘g’ in terms of myelination, cortical thickness, and the development rates in the cortex in more gifted children. For a summary and discussion of this see this paper by Thompson & Gray. www.loni.ucla.edu/~thompson/PDF/nrn0604-GrayThompson.pdf
8. For a more recent study of myelination which affects processing speed, this was discussed in the March 2009 issue of New Scientist:
“It is clear that intelligence is at least partly genetically determined. This was supported by the discovery in 2001 that the volume of the brain’s grey matter, made up of “processor” cells, is heritable and correlates with certain elements of IQ (Nature Neuroscience, DOI: 10.1038/nn758). The amount of white matter, which provides the connections between these processors, has since been shown to be heritable too (Journal of Neuroscience, vol 26, p 10235).
Now it seems that the quality of these connections, which is governed by the integrity of the protective myelin sheath that encases them, is also largely genetic, and correlates with IQ...
By comparing brain maps of identical twins, which share the same genes, with fraternal twins, which share about half their genes, the team calculate that myelin integrity is genetically determined in many brain areas important for intelligence. This includes the corpus callosum, which integrates signals from the left and right sides of the body, and the parietal lobes, responsible for visual and spatial reasoning and logic (see above). Myelin quality in these areas was also correlated with scores on tests of abstract reasoning and overall intelligence (The Journal of Neuroscience, vol 29, p 2212).”
http://www.newscientist.com/article/mg20126993.300-highspeed-brains-are-in-the-genes.html
And the page I linked to splits up the Flynn Effect between fluid g and crystalized g and points and it shows not only increases in both but a greater increase in tests which measure fluid intelligence, which is less reliance on learned information. So what are they missing?
Sowell points out several red flags that suggest problems in the black community, including his point that "females predominated among high-IQ blacks" while white males and females have the same average IQ. Not only does that suggest something other than pure heredity is going on (since those black males and females have the same ancestry) but that other claims about "g" such as it's correspondence to brain size are not as straightforward as suggested. Another curiosity lies in HIspanic IQ test performance, given that Hispanics are often genetically quite European in ancestry. I also think it's very difficult to argue that if an exposure to gadgetry improves visual logic that environment has no impact on tests that measure things like general knowledge, mathematics, or vocabulary and that growing up in an environment that stresses or exercises none of those things will have no impact on achieving a person's potential maximum.
While it's true that the Flynn Effect gains may not be measuring gains in general intelligence, they are measuring gains in the tests of intelligence from which conclusions about "g" are drawn, thus deficiencies in performance with with the non-"g" components that the tests measure can impact the attempt to measure "g" using the test. Noise may be making it difficult to measure the signal.
As I have pointed out earlier, there is evidence that the Flynn Effect has narrowed the gap from 3-6 points in recent decades and if it's reversing in some cases, it still raises the question of why it changes and how much those changes affect the measurement of "g".
1. No doubt if everyone had equal conditions part of the gap could perhaps be reduced. One problem Jensen has pointed out is that generally there is a trend where the more educated women have fewer children. Jensen has noted that this actually affects the black community even more than the white community. If that’s the case, it will make closing the gap harder.
“there is evidence that the Flynn Effect has narrowed the gap from 3-6 points in recent decades”
2. Some other discussions of this.
That comment is based on this paper “Black Americans reduce the racial IQ gap: Evidence from standardization samples (Dickens, Flynn; 2006), still show gains between 1972 and 2002.”
A point made on GNXP was that the trend appeared to be amongst children, rather than adults. They note that hereditary influences increases with age. For instance, on the transracial adoption studies there was considerable convergence at age 7, but this wasn’t the case when re-tested at age 17. http://www.gnxp.com/blog/2006/08/more-on-dickens-flynn-paper-regarding.php
Here is a paper in repy published in the same journal.
Rushton, J. P., & Jensen, A. R. (2006). The totality of available evidence shows race-IQ gap still remains. Psychological Science, 17, 921-922.
http://psychology.uwo.ca/faculty/rushton_pubs.htm
3. Just reading that Sowell piece I see he mentions the rising Jewish test scores. This is based on a canard.
The idea that Jews tested poorly is actually based on a misrepresentation of a paper authored by Henry Goddard in 1917. Goddard gave IQ tests to people suspected of being mentally handicapped. He found the tests identified a number of such people from various immigrant groups, including Ashkenazi Jews. Leon Kamin in 1974 reported that Goddard had found Jews had low IQ scores. However, Goddard never found that Jews or other groups as a general population had low scores. There is other information that contradicts the idea that Jews did poorly on IQ tests around this time. In 1900, in London, Jews took a disproportionate number of academic prizes in spite of their poverty (C Russell & H.S. Lewis ‘The Jew in London’ Harper Collins 1900). Also, note that by 1922 Jewish students made up more than a fifth of Harvard undergraduates & the Ivy League was already instituting policies aimed at limiting Jewish admissions (the infamous ‘Jewish quotas’). Also, a 1920’s a survey of IQ scores in three London schools with mixed Jewish & non-Jewish student bodies - one prosperous, one poor and one very poor - showed that Jewish students, on average, had higher IQ’s than their schoolmates in each of the groups (A Hughes 1928).
- see also: G. Cochran, J. Hardy, H. Harpending, Natural History of Ashkenazi Intelligence, Journal of Biosocial Science 38 (5), pp. 659-693 (2006).
http://homepage.mac.com/harpend/.Public/AshkenaziIQ.jbiosocsci.pdf
On point (1), African Americans are not the only black people on the planet so that raises the question of whether people are talking about African Americans as a community or all black people as a race, and that further raises issues about the differences in performance between not only black immigrant groups and African Americans but also the ethnic differences within the African American community that are often ignored (e.g., North and South, Carolinas vs. Deep South, etc.).
From what I’ve read, there is more genetic diversity among humans in Africa than between those in Africa and the rest of the world, yet there is less difference between blacks than between blacks and the rest of humanity? Further, if general intelligence is really inherited and a good indicator of economic success (as has been suggested), then one would expect differences and gaps between various black groups (and Hispanic groups, which can be even more genetically and economically different from each other).
On point (2), the cultural influences outside of the family also increase with age such that I don’t think it’s so easy to conclude that the differences are hereditary rather than cultural. If the differences really are a matter of “processing speed” and issues such as myelination, do you have evidence that it (and other brain structure differences) change substantially between the ages of 7 and 17?
On point (3) you may be correct but it points to why people are skeptical about race-based research on intelligence, that there is a long and ignoble history of it being used by bigots to justify bigotry and even the extermination of racial and ethnic groups. That it’s been misused not only makes the research suspect but also shows why extra skepticism is warranted and the burden of proof should be closer to “beyond a reasonable doubt” than “some research shows”.
Further, Sowell doesn’t simply use Jews as an example but also Poles and other ethnic groups. In the case of Polish-Americans, the IQ tests were administered by the military to recruits.
Please note that I don’t think you are racist for raising these points and I’ve defended Jensen in other more liberal forums where it’s assumed that anyone asking these questions is automatically racist. But I do think a lot of skepticism is healthy because the implications of getting this wrong are significant. I would also be more persuaded by physiological evidence tied to the communities and and test results in question (e.g., some biological explanation for why the performance between black and white children widens between 7 and 17) before assuming that it’s biological.
“do you have evidence that it (and other brain structure differences) change substantially between the ages of 7 and 17?”
There has been some interesting research in relation to the development of the cortex in gifted children.
According to this new study, children with the highest IQs start out with a thinner cortex, which undergoes rapid growth, peaking at around age 12, instead of age 8 or 9 for children who got average scores on IQ tests. “Children with the most agile minds have the most rapidly changing cortex,” says Philip Shaw, a child psychiatrist at NIMH who led the research.
http://www.technologyreview.com/biomedicine/16641/
A good discussion of the hereditability of brain structure is set out here by Steve Hsu, in relation to a paper by Paul Thompson from UCLA (Review Paper, Nature Reviews Neuroscience 5:1-13, June 2004, published online, May 19 2004):
“A subsequent study in a larger, independent sample34found that variations in total grey matter volume were almost entirely attributable to genetic factors... These genetically mediated differences in brain structure explain a proportion of the variation in general cognitive ability. This ability is also influenced by non-genetic factors such as education and nutrition, prenatal and family environments, training and environmental hazards such as lead poisoning.”
http://infoproc.blogspot.com/2009/02/heritability-of-brain-structure.html
“genetic diversity among humans in Africa than between those in Africa and the rest of the world,”
I’ve found Steve Hsu’s comments very helpful in terms of genetic studies:
This sets out the genetic distance between groups:
“Genetic distances between population clusters are roughly as follows: the distance between two neighboring western European populations is of order one in units of standard deviations and the distance to the Russian cluster is several times larger than that — say, 3 or 4. From HapMap data, the distance from Russian to Chinese and Japanese clusters is about 18, and the distance of southern Europeans to the Nigerian cluster is about 19. The chance of mis-identifying a European as an African or E. Asian is exponentially small. (Table 5)”
http://infoproc.blogspot.com/2008/11/european-genetic-substructure.html
Also, for a discussion of the Lewontin fallacy (more within group variation than between group variation), Hsu explains:
“Further technical comment: you may have read the misleading statistic, spread by the intellectually dishonest Lewontin, that 85% percent of all human genetic variation occurs within groups and only 15% between groups. The statistic is true, but what is often falsely claimed is that this breakup of variances (larger within group than between group) prevents any meaningful genetic classification of populations. This false conclusion neglects the correlations in the genetic data that are revealed in a cluster analysis. See here for a simple example which shows that there can be dramatic group differences in phenotypes even if every version of every gene is found in two groups — as long as the frequency or probability distributions are distinct. Sadly, understanding this point requires just enough mathematical ability that it has eluded all but a small number of experts.)...
“On the other hand, for most phenotypes (examples: height or IQ, which are both fairly heritable, except in cases of extreme environmental deprivation), there is significant overlap between different population distributions. That is, Swedes might be taller than Vietnamese on average, but the range of heights within each group is larger than the difference in the averages. Nevertheless, at the tails of the distribution one would find very large discrepancies: for example the percentage of the Swedish population that is over 2 meters tall (6”7) might be 5 or 10 times as large as the percentage of the Vietnamese population. If two groups differed by, say, 10 points in average IQ (2/3 of a standard deviation), the respective distributions would overlap quite a bit (more in-group than between-group variation), but the fraction of people with IQ above some threshold (e.g., >140) would be radically different. It has been claimed that 20% of all Americans with IQ > 140 are Jewish, even though Jews comprise only 3% of the total population.”
http://infoproc.blogspot.com/2008/01/no-scientific-basis-for-race.html
“An interesting article on race and IQ by Malcolm Gladwell”
I recently posted on Slate about this article. Here’s what I wrote:
1. In relation to the Flynn effect this is attributed to a combination of different environments (most gains are domain specific) and improved nutrition in some cases. However, there is no sign that this has actually reduced the b-w gap over the past 30 years. The B-W IQ gap is larger at the highest level of SES than at the lowest. There have been literally hundreds of IQ studies of various racial groups from many different countries and they show the same outcome. Also, the Ashkenazi Jewish average remains about 2/3 of a std deviation above the white average.
2. Looking at children’s scores overlooks the point that the impact of hereditability increases with age. This is long before the shared environmental component vanishes. The IQ boosts that have been reported with Head Start type interventions were temporary (very short lived) and were believed to be largely the result of teaching to the test. The shared environmental component equals zero for adults.
3. If you look at twin and adoption studies all adopted children reached adult IQ’s that were equal to their biological peers and which had no correlation with their adoptive families. Transracial studies were not limited to Blacks adopted by Whites but included Asians adopted by Whites. The Blacks ended up with lower IQs than their adoptive families and the Asians ended up with IQs higher than their adoptive families.
4. The GI study in WWII is not convincing. It is known as the Eyferth study. Environmental proponents always cite it because they have not found any other evidence to cite. Note that:
* The “study” consisted of a very small N. Some citations claim 98 and some 69. * Although the children’s IQ was measured, the parents’ IQ was not measured (neither was the rank of the US military father measured). So it is not known whether the children inherited the parental IQ.
* About 30 percent of US blacks failed pre-induction mental tests for the military, compared with 3 percent of white. So US black soldiers were a more IQ-selected and less-representative sample of their population than were white soldiers.
* Children were tested prior to the age at which the genotypic aspect of intelligence has become fully manifested. * 20% to 25% of the Black fathers were not African Americans but French North Africans.
5. Electroencephalography measurements of various types confirm the W-B gap. In fact, there are two index methods, using average evoked potentials and amplitude measurements, that can measure g as well as the best IQ tests.
6. The gap is lower on culturally loaded tests and higher on culture free or culture fair tests. The reason is that Spearman’s Hypothesis has been shown to be correct. When cultural factors are removed from tests, the resulting tests are more g-loaded. As g-loading increases, the W-B gap increases. (Jensen, Bias in Mental Testing)
7. The rate of evolution has sped up over the past 10,000 years (see ‘The 10,000 Year Explosion: How Civilization Accelerated Human Evolution’ by Cochran & Harpending). For example, you see new versions of SLC6A4, a serotonin transporter, in Europeans and Asians. There’s a new version of a gene (DBA1) that shapes the development of the layers of the cerebral cortex in east Asia.
The Government had tried to make education ‘accessible’ rather than ‘ rigorous’, he said.
Doing that here too.
Thanks, I knew everything you wrote about except #6 that g loading increases as cultural factors are removed from intelligence tests.
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