That was great, how do you snag all these bigwigs for your blog?

Before Jensen, the notion that all races were genetically equal for cognitive ability had become a dead "Sunday truth"...

I'm aware that in this day, it is political incorrect to say in public that there are differences in intelligence between racial groups. But I think we will denying reality if we don't acknowledge that, in modern western history (including the US), it is a widely held belief that there are racial differences in intelligence. And specifically, blacks were believed to have the lowest intelligence. That belief was certainly held in the decades before 1980. Public discussion of the issue was not widespread but that was mainly a function of political changes that were happening in the country. For the first time, blacks were beginning to have rights they have never enjoyed as citizens. Things don't happen in a vacuum. So I don't think Flynn is quite correct in saying that was a "Sunday truth".

I'm not quite sure what Flynn means by "Sunday Truth". According to this "Sunday Truth" is an expression invented by Bertrand Russel meaning something we agree on in form without agreeing on anything in substance. I can see how that would apply to human equality in the abstract, but it seems to me that the idea of equal intelligence is reasonably well defined.

It's not impossible that blacks are less intelligent than whites. However, what would the definition of black be in order to study this point? What about the Andamanese/Solomon Islanders/Negritos? By virtue of appearance are they black? If not, where would they be expected to fall in the IQ scale?

maybe, I'm misinterpreting what Flynn meant by the term...

Help me out here:

But it is not a test of reading comprehension but a test off perceiving the "logic" of social arrangements - for example, why streets are numbered in order.

In what way is having streets numbered in order a social arrangement?

My first understanding of that sentence related to street numbers, ie, houses on a street, however, being familiar with streets in San Francisco it is possible that he is referring to First street, second street, third street and so forth.

So, I am at a loss to understand what he means. There is no other logical way to number streets, although the practice in the West of the US (or is it only the Bay Area?) of leaving large gaps between numbers is semi-logical. However, the number nightmare that is El Camino Real is unwarranted.

Dataset,

I think "black" refers to people of sub-Saharan African descent. Obviously, these people are called black because here in America, for a very long time they were the only black-skinned people running around. But there are black-skinned Indians who are genetically closer to Europeans than they are to sub-Saharan Africans, and thus aren't "black" in the racial (as opposed to the cosmetic) sense of the word.

My next book is in press. It will be called: The hollow center: race, class, and ideas in America. It will attempt to shake Americans into awareness that they are blind to the state of black America, that their foreign and domestic policies have perverse priorities, that they are class blind, and have lost their way it terms of Jefferson's humane ideals. It is, however, a hopeful book in the sense that there is much in America's history that can show us how to find our way.

I think his best books are behind him. This is the stage of his career where he stops bothering with facts and gets polemical; he is pulling a Stephen Jay Gould.

I disagree with Keith. It may be more accurate to say that Flynn's best scientific books are behind him. What he is doing now is synthesizing from a wide perspective, something that is appropriate if a person has spent a lot of time thinking about the broader issues relating to their discipline. If polemics are not your cup of tea, then indeed his best work is behind him. For those of us who find discussions of broad societal issues potentially interesting, Flynn's next book may be a worthwhile read.

I see nothing wrong with a polemic as long as it is well argued and has an appropriate factual basis. Since I found "What is Intelligence" very interesting and well argued, I look forward to his future publications. Flynn has already stated that he is switching to philosophical discussions. He has given fair warning that he is no longer doing science.

Just because he is writing a polemic doesn't necessarily mean it won't be good work. It does mean it will be different. After it comes out we can form our opinions about the value of his book.

One thing I think I've come around to agreeing with Flynn on is that focus on g might not be the best path to fruitful research. My impression from what I've read up on is that most of the variance in g can be explained by a combination of working memory and transmission efficiency, which seem like pretty tractable problems to work on. g needs to be decomposed eventually, and now seems like a fine time for it.

I like the bit about SHAs, too. Very important, I think. Flynn is weakest when arguing against nutrition, though: Even within *developed* countries, presence of certain micronutrients correlates with IQ, and it's plausible to me that a lot of people in developed countries suffer from this kind of nutritional deficiency for some things even today. Also, there's another factor that he doesn't address: lead.

He's also talking out of both sides of his mouth when he says the gains aren't g-loaded: He himself has pointed to the fact that the scores are highest on the Raven's and that the questions on the WISC that correlate most highly with Raven's scores tend to show the biggest gains as a way of refuting Rushton. Which suggests that while crystallized g hasn't changed much, fluid g has.

Congratulations to Prof. Flynn for taking the time to reply to the questions and to my gnxp colleagues for obtaining his contribution. Certain parties are inclined to dismiss gnxp as 'blithering idiots'. Maybe they should take a closer look at the list of '10 questions' participants.

I suspect that Question 6 may have been inspired by some past comments of my own. If so, I probably did not put them very clearly. Let me restate my point.

There is respectable evidence for the proposition that IQ tests are more highly g-loaded at lower IQ levels as compared with higher IQ levels. In more concrete terms, if you divide the tested population into two halves, upper and lower, and analyse the results separately, you will probably find that the performance of individuals on a variety of different tests or test items is more highly correlated in the 'lower' half than in the 'upper' half. (For evidence, see N. J. Mackintosh, 'IQ and Human Intelligence', p213, or A. Jensen, 'The g Factor', Appendix A. There is also something in Jensen's main text, but I can't immediately find it.)

This could be interpreted as showing that there are more ways of being intelligent than of being stupid. Or it could be that as you move up the scale of difficulty in an IQ test (e.g. Wechsler or Raven's) the questions are actually testing a more diverse range of abilities. Or both.

The relevance of all this to the Flynn Effect is that if the population is, on average, more intelligent than it used to be, say, 50 years ago, then you would expect the factor composition of tests, as shown by test results of the current population, to have changed compared with the earlier population. In general, you would expect g loadings to be lower.

What I would like to know is whether this has actually been observed. I don't think Prof. Flynn has addressed this point, but I admit I haven't yet read his new book. Nor do I think he should dismiss the point as irrelevant, because it could be an answer to some of the criticisms he has faced, e.g. that the IQ gains are 'hollow'.

8. Out of the many research designs you propose in What is Intelligence, which one would you most like to see performed and why?

The one that calls for investigation of urban and rural Brazil. I think the former approximates where Americans are today, and the latter approximates where Americans were in 1900. We could get direct evidence for or against the cognitive history of Americans in the 20th century that my book relates.

I've suggested before that Amish IQ should be measured, especially because the little data I have seen so far puts the average right around 100. If that is the case, it certainly points to 20th century cultural changes having little relevance.

What is the current Amish/mainstream IQ gap? Does anybody know?

One of my colleagues, with access to the Wechsler data, tells me he reviewed the factor structure for high and low IQ groups, and found no difference.
Unfortunately, I couldn't find the reference on Google Scholar (some people publish too much).
Does this help, David B.? The data is out there, it wold be a matter of minutes to test the Spearman hypothesis.

What is the current Amish/mainstream IQ gap? Does anybody know?

That's a great question, for so many different reasons. You'd think someone would have done a study on this.

Thanks for this excellent interview.

It may be more accurate to say that Flynn's best scientific books are behind him. What he is doing now is synthesizing from a wide perspective, something that is appropriate if a person has spent a lot of time thinking about the broader issues relating to their discipline.

freds' comment is dead on IMO. I look forward to Flynn's new book.

This New York Times article seems to point towards changes in biological environment being at least partly responsible for the Flynn Effect.

Hopefully I'm not quote mining:
http://www.nytimes.com/2006/07/3...? pagewanted=all
Even the human mind seems improved. The average I.Q. has been increasing for decades, and at least one study found that a person’s chances of having dementia in old age appeared to have fallen in recent years.

He compared two populations: those whose mothers were pregnant during the flu epidemic and those whose mothers were pregnant shortly before or shortly after the epidemic.

To his astonishment, Dr. Almond found that the children of women who were pregnant during the influenza epidemic had more illness, especially diabetes, for which the incidence was 20 percent higher by age 61. They also got less education — they were 15 percent less likely to graduate from high school. The men’s incomes were 5 percent to 7 percent lower, and the families were more likely to receive welfare.

The effects, Dr. Almond said, occurred in whites and nonwhites, in rich and poor, in men and women. He convinced himself, he said, that there was something to the Barker hypothesis.

The lower incomes, lower higher school graduation rate, and higher welfare usage point mom's illness during pregnancy lowering IQ.

Apparently, the Amish typically don't vaccinate, but they still benefit from herd immunity, and should have benefited from reduced infectious disease.

David wrote:

There is respectable evidence for the proposition that IQ tests are more highly g-loaded at lower IQ levels as compared with higher IQ levels.

This has been shown by factor analysis of top and bottom halves and by correlating the scores between two different IQ tests for high and low range testees. See: Kane, H. & Brand, C. R. (2001). 'The Structure of Intelligence in groups of varying cognitive ability: a test of Carroll's three-stratum theory.'

This could be interpreted as showing that there are more ways of being intelligent than of being stupid. Or it could be that as you move up the scale of difficulty in an IQ test (e.g. Wechsler or Raven's) the questions are actually testing a more diverse range of abilities. Or both.

It shows that group factors (expressed as residuals) are increasingly important as intelligence increases. Over most of the populatiuon, group factors (narrow abilities) account for virtually none of the external validity of the test.


What I would like to know is whether this has actually been observed.
I have not seen any papers that show a secular decline in g loading. One paper showed the expected FA gain over 20 years, but no change in inspection time measurements. The study was very carefully done with the same equipment, same school, and same researchers. If there was a g loading on the FA gain, the IT should have decreased. It did not.

So far, there is little evidence of a gain in g, but there is one paper that will be presented next week that argues for a small g increase.

"Certain parties are inclined to dismiss gnxp as 'blithering idiots'. Maybe they should take a closer look at the list of '10 questions' participants."

I've seen commentators unhappy about GNXP's straight-forward inquiry on the human sciences, but I've never seen anyone disparage the intelligence of GNXPers. (That would indeed seem ironic, given the disparity in scientific literacy etc.)

Matt wrote: "One thing I think I've come around to agreeing with Flynn on is that focus on g might not be the best path to fruitful research. My impression from what I've read up on is that most of the variance in g can be explained by a combination of working memory and transmission efficiency, which seem like pretty tractable problems to work on. g needs to be decomposed eventually, and now seems like a fine time for it."

It is true that both working memory and speed related measurements correlate strongly with g, as does brain volume, especially at the cognitive centers. If by "decomposed" you mean that we should focus on the underlying biology, I agree with you. If you mean to simply understand the fine structure, that is already available from the factor analysis.

"He himself has pointed to the fact that the scores are highest on the Raven's and that the questions on the WISC that correlate most highly with Raven's scores tend to show the biggest gains as a way of refuting Rushton. Which suggests that while crystallized g hasn't changed much, fluid g has."

I disagree. No test, even the Raven's is free from s loading. There is plenty of specificity in the Raven's and WISC to allow for raw score increases. Keep in mind that Gc is about 80% g loaded. As you may know, Bouchard and Johnson have argued rather strongly that Gc is not a separate g (as in the Cattell-Horn model that identifies Gc and Gf, but does not extract g).

The Amish are interesting not just in terms of any Amish/mainstream IQ gap but also for the Flynn effect as well. From the "Proposed explanations" section of the Flynn effect from Wikipedia:

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]

None of which apply to the Amish or if they do, not nearly to the same degree. Also, it seems the Amish had the mainstream average IQ about 40 years ago. Alas, you can't do much without data. If only researchers had the forsight to comprehensively study the Amish 75 years ago knowing that there would be little to no change in the environment and genetics of these people compared with the world around them.

But I suppose it doesn't really matter now since that sort of thing is rapidly becoming obsolete.

"Some Random Wierdo" states that "there is no other logical way to order streets."

In Japan, the houses are usually numbered by neighborhood, not by street. Assume a town called Kazetani with multiple neighborhoods; assume one neighborhood is called Taneda and takes up four or five square blocks with several streets. If you live in that neighborhood, your address might be 57 Taneda. Your next door neighbor could be 32 Taneda, and 58 Taneda could be three streets over.

You can't find your way to a specific person's house without a map! Detailed maps are published of every city showing the neighborhoods and individually numbered houses. (I spent 2 years there and eventually got pretty good with the maps.)

Somebody eventually told me that the houses were numbered in the order they were built. I'm not sure whether that person was pulling my leg or not.

Question: Is it any less logical to number houses in a tract in the order they were built, than to number them consecutively along a single street?

Steve - Answer: Yes.

Thanks to Vantage for his/her comments on my comments.

I don't quite understand the last part of his/her comments. If g-loadings are lower at high IQ levels (as the first part of his/her comments agrees), and if average IQ has increased relative to earlier norms (as everyone agrees), then surely there must have been a secular decline in g loadings. The loading of g (or any other factor) is relative to the tested population. Or am I missing something?

I think your point is valid, but I have not seen any papers that have reported changes in test g loading. I expect to be talking to the most knowledgable people (Lynn, Rushton, Deary, Flynn, etc.) in this area in just a few days and will see what they have to say.

One factor is that the gains have been greatest among low IQ people. This may reflect a decrease in the number of people who are adversely affected by serious cognitive disorders. At the low end, the variance in IQ is believed to be overwhelmingly due to higher or lower g. The question is whether increased scores change the total test loading between the three factors: g, s, and e. (s = specificity and e = random error) The sum of the squares of these three factors must equal 1.0. That means that, if s loading increases g will decrease, assuming e is constant.

Vantage: Thanks. Let us look forward to greater enlightenment from the Masters!

On Flynn's answer to Q. 9, reduction in family size would have some environmental effect on children's IQ, but I doubt that in itself it would explain a large part of the Flynn Effect. There was an important study on the effects of family size by John D. Nisbet in Britain in the early 50s ('Family Environment', Eugenics Society Occasional Paper number 8, 1953), which suggested that the effect of increasing family size was to reduce mean IQ by between 2 and 4 points per extra child. Presumably reducing family size would increase IQ by a similar amount. But reducing average family size from, say, 4 to 2, would hardly account for more than 8 points of the Flynn Effect total of over 20.

But I repeat that I haven't yet read Flynn's book, so maybe he gets the numbers to pan out.

In the study on family size and IQ did they control for people with higher intelligence having smaller families by comparing families with similar parental IQ?

Question: Is it any less logical to number houses in a tract in the order they were built, than to number them consecutively along a single street?

it might depend on how that society is organized. build order numbering gives ppl a sense of how old the house might be. in a less mobile society it might also connote a family's "seniority" in the neighborhood.

my speculation may have zilch to do w/ why it was actually numbered that way, but without understanding their values it would be difficult to say whether its logical b/c there is information contained in the numbering.

I think the street numbering in Japan is a sign that the society values precedent over common sense - to me the chaotic street numbering, offers almost no utility, and so is clearly stupid.

perhaps the chaoticness also serves a function. if a particular society doesn't particularly welcome outsiders but still wants to receive mail, this would create a disincentive to entering the area w/o good reason as long as ur an outsider.

but if precedence is the only factor, then yeah thats pretty dumb.

talked to a guy that lives in japan and he also heard that buildings are numbered by build order. he also mentioned that there are streets w/o names and even vet taxi drivers need u to point to a map to get u where u need to go. so... seems like precedence is the controlling factor.

another person said that suburban areas are structured differently. so it may just be urban areas (in cities that had to be rebuilt after war? or not?) that have this issue.

It might depend on how that society is organized. build order numbering gives ppl a sense of how old the house might be.

Or you could just hang a little plaque with the date the house was built on it, like they do in my historical home town. Sometimes these plaques even have the date AND the address on them!

Sorry. Long day at the office. :)

Henri:

I'm no expert on the Amish. But I've lived not too far from one of their principal "strongholds"--Lancaster County in SE PA--and travelled that region sufficiently to have made observations.

First, the Amish consist of a number of subdivisions and are, themselves, a subdivision of the Mennonites. Different groups have differing relationships and views regarding modernity but a great deal of their lifestyle, including eschewal of available conveniences, stems from an attitude not specifically religious but practical. Since it seems to them that the world of outsiders is characterized by so much strife, controversy, and "wickedness," they've made a conscious choice to avoid those negative influences by the relatively simple expedient of holding themselves apart; in so acting, they hope to avoid inevitable negative encounters with others, and exposure to temptations of ease, luxury, etc., as well as of specifically sinful behavior. But, as I said, there are many groups. Some are building contractors, both residential and commercial (and many of those seem to be named "Stolzfuss") and employ tools (including powered) as might other contractors. Many are in "farmers' market" activities retailing produce, baked goods, confections, and crafts. How many eschew electronic calculators (or computers), I can't say but can tell you the principal transport is commercial vans (rather than horse-and-buggy rigs ubiquitous on the county roads). At least some of the farmers employ conductivity cells to determine soil moisture content (I deal in lab items and have sold such to dealers supplying that specific market.) It is my understanding that, in the main, they are not "cheating" in doing so but have council or committees, to consider such practices, case-by-case.

They are in a peculiar position with respect to "the law of the land" wherever they live, trying to conform to the greatest extent consistent with their beliefs but, almost universally, steadfastly opposed to utilizing the agency of the state to settle competing claims, to compensate or sue for damage sustained, etc. In many cases, they even refuse proferred compensation for damage inflicted accidentally , accepting, at maximum, personal, physical assistance from the at-fault party to repair damage. As far as I know, they'll not even mount a defense in court (though they've been defended in certain cases by the ACLU) against the claims of others or the law.

I agree that the general group would have been presented certain advantages for those studying
IQ. Not only would it have been possible to find succeeding generations of lifestyle nearly identical to their parents and grandparents but there'd have also been ready-made groups for comparison--differing only in having elected (or been required) to leave for the mainstream lifestyle. Actually, it still might be a good idea (even though the results would not be available for quite some years).

David,
... suggested that the effect of increasing family size was to reduce mean IQ by between 2 and 4 points per extra child. Presumably reducing family size would increase IQ by a similar amount. But reducing average family size from, say, 4 to 2, would hardly account for more than 8 points of the Flynn Effect total of over 20.

A good while back, parity was assumed to account for a decrease in IQ on a within family basis. Then a paper came out saying that the effect was entirely due to low IQ people having larger families (statistically) and smart people having small families. The family size thing is true. Researchers bought the explanation, until this year. A new study, with large N, was reported from Norway, showing that the first idea was correct. It showed that the largest IQ decrease was for the second born child. This opened the door (again) to arguments that some of the Flynn effect is due to a steady decrease in family size.

Gene, Henri,

I saw a documentary (PBS?) that was about Amish youth coming of age... one thing that struck me was that they didn't use electricity BUT one of the teenagers had a large battery - from a car perhaps - that powered his PC, and he was playing video games in his room?!

"In the study on family size and IQ did they control for people with higher intelligence having smaller families by comparing families with similar parental IQ?"

Nisbet did attempt to alow for this - indeed, this was one of the main purposes of his study. He did not directly control for parental IQ, which is seldom known, but used various less direct approaches, such as controlling for birth order.

The figure I quoted of a difference of 2 to 4 IQ points per extra child is a raw figure which should probably be taken as an upper limit to the environmental effect.

8. Out of the many research designs you propose in What is Intelligence, which one would you most like to see performed and why?

The one that calls for investigation of urban and rural Brazil. I think the former approximates where Americans are today, and the latter approximates where Americans were in 1900. We could get direct evidence for or against the cognitive history of Americans in the 20th century that my book relates.

I had a chance to look up more on the Amish and it turns out that Amish children have consistently and currently still score at or slightly above the norm on standardized tests.

This is despite more than a few possible handicaps.

1) no kindergarten so there is one less year overall (grades 1-8)
2) all instruction is in English which they start learning when they enter
3) teachers have the same Amish eighth grade education
4) one-room school so no division by grade or ability
5) use old primers

So not only do the Amish have a 19th century lifestyle, their children are taught in a 19th century manner. I think this is closer to America in 1900 than anything you'll find in Brazil. And they score around the norm on standardized tests which might indicate "average intelligence". Also (as stated earlier), none of the proposed explanations of the Flynn effect (improved nutrition, a trend towards smaller families, better education, greater environmental complexity, and heterosis, familiarity with multiple-choice questions and brain-teasers) apply to them so it would be an excellent opportunity to look at overall IQ and certain subtests vis-a-vis the mainstream.

pconroy, that kid was probably in that experimental period when they allow teenagers to try out normal life for a time.

So not only do the Amish have a 19th century lifestyle, their children are taught in a 19th century manner. I think this is closer to America in 1900 than anything you'll find in Brazil. And they score around the norm on standardized tests which might indicate "average intelligence".

This is what you would expect. Intelligence is a reflection of biological factors, not of educational attainment. People tend to get educations that are roughly in line with their level of intelligence, but whether they do or don't, their IQs will remain relatively stable from about the age that they start school. If school mattered, IQ would increase in proportion to the years (and quality) of education received. That doesn't happen.

vantage, see Flynn's response to question 3 which is pretty much the opposite of all you said. I know you probably disagree with him, but apparently he knows something about this subject. ;) I'm not challenging what you said and I'm not interested in debating this topic, just saying it's probably not as simple as you make it out to be.

The result was a pattern of IQ that put the subsequent generation of Chinese Americans at an IQ of 109 at say age six gradually falling to 103 by the late teens, as parental influence faded away in favor of peers. The extra 3 points the present generation has as adults is due to the fact that they are in cognitively more demanding universities and professions and because they have internalized a positive attitude to cognitively challenging activities and companions.

I think it's plausible there are different types of intelligence and that emphasis on one or another can change those abilities or testing for them. For example, there is no science instruction in Amish schools. Does that mean they will test poorly in raw cognitive abilities related to science even though their "overall average intelligence" seems to be the same?

Add creativity to the list of possible differences since they apparently make no effort to teach it. Can it be taught in our schools? Hard to measure for sure, but still interesting; especially for the "new economy".

RE: Asians.

Pretty much all of this was already covered in his Asian-American book in 1991. Even then he accepted that IQs were higher in some Asian countries. Also he accepted that some smaller studies showed higher IQ for Asian-Ams during the 1980s. He attributed this to the socioeconomic advantages these kids got from their lower IQ overachieving parents.

The update in his new book repeats this theory, but there is no data for it.

It is doubtful because the effect of shared environment, including SES, on IQ is 0.

More plausibly, it is related to rapid change in the demographics of Asian-Americans after 1965.

"If school mattered, IQ would increase in proportion to the years (and quality) of education received. That doesn't happen."

But it does, doesn't it? N. Mackintosh, 'IQ and Human Intelligence', p.131: "One well-established educational correlate of IQ is the number of years of formal education recieved". The problem is to separate the chicken from the egg: do people with more/better education have higher IQs as a result, or do people have more/better education because they have higher IQs to start with?

Mackintosh, pp.131-139, quotes several lines of evidence suggesting that education does have some effect, the clearest being that children of the same age, who for institutional reasons have started school at different ages, differ significantly in IQ. Teasdale and Owen also report an educational effect in their studies of Danish army recruits. For older studies see Anastasi's 'Differential Psychology'.

As to 'quality' of education, there were some relevant studies of the effects of the selective '11 plus' system in Britain. It was found that children who went to grammar schools (more academic education) had higher IQ at later ages than those who had the same tested IQ at age 11 but who for purely institutional reasons (e.g. shortage of places in their locality) went to the less academic 'secondary modern' schools.

Henri,

vantage, see Flynn's response to question 3 which is pretty much the opposite of all you said. I know you probably disagree with him, but apparently he knows something about this subject.

Yes, I disagree with him. He has stubbornly argued that the environment is the determinant of intelligence and has argued with weak and nonexistent evidence. Heritability can be measured by multiple and diverse approaches and all yield about the same result: 80% in adults. Flynn went to the extreme of inventing a magical relationship between the environment and genes and accompanied it with equations showing his idea to be possible, but it was entirely imaginary. [see Flynn and Dickens]

I think it's plausible there are different types of intelligence and that emphasis on one or another can change those abilities or testing for them.

Gardner and Sternberg also think there are different types of intelligence. Neither of them has demonstrated that such is the case. Like Flynn, they have used invention and assertion in place of science (factor analysis in particular).

For example, there is no science instruction in Amish schools. Does that mean they will test poorly in raw cognitive abilities related to science even though their "overall average intelligence" seems to be the same?

If you test someone on a subject that he has not been taught, you are administering an invalid test. You already know that don't you? If you give a Frenchman an IQ test in Chinese, the test is not valid, unless the Frenchman is a fluent (at native language level) Chinese speaker. But you can give Amish, French, and Chinese the same Raven's test and the results will have similar predictive validity.

"If school mattered, IQ would increase in proportion to the years (and quality) of education received. That doesn't happen."

But it does, doesn't it? N. Mackintosh, 'IQ and Human Intelligence', p.131: "One well-established educational correlate of IQ is the number of years of formal education recieved". The problem is to separate the chicken from the egg: do people with more/better education have higher IQs as a result, or do people have more/better education because they have higher IQs to start with?

IQ and the number of years of education are strongly correlated and years of education can (if you understand the error involved) be used as a proxy for IQ. That does not mean that IQ is not stable, nor does it imply that IQ increases as people go through additional years of schooling. It simply means that more intelligent people are more inclined to pursue additional education and less intelligent ones are more inclined to do something else. This may be of interest to you:

The prediction, from infancy, of adult IQ and achievement
Intelligence, vol 35, issue 3, 2007
Pages 225-231
Joseph F. Fagan, Cynthia R. Holland and Karyn Wheeler

IQ from 3 to 21 years appears to be quite stable and achievement at 21 years is predicted about as well by the IQ estimate at 3 years as it is by IQ at 21 years.

Mackintosh, pp.131-139, quotes several lines of evidence suggesting that education does have some effect, the clearest being that children of the same age, who for institutional reasons have started school at different ages, differ significantly in IQ. Teasdale and Owen also report an educational effect in their studies of Danish army recruits. For older studies see Anastasi's 'Differential Psychology'.

The only differences seen in IQ measurements that are attributable to education are gains in the non-g measurements that are attributable to specificity. So far, there have been no studies that have demonstrated that g increases as a result of any kind of training. The s gains are effectively errors in IQ measurement. If you coach someone to take the SAT, his scores will increase because he can apply learned approaches to some test items. His s loading will increase (for that test) and that means that the g loading of the test (for him) decreases. This score boost is not a boost in intelligence and is usually found to be temporary, such that a retest at a later date will show most of the boost to be gone.

As to 'quality' of education, there were some relevant studies of the effects of the selective '11 plus' system in Britain. It was found that children who went to grammar schools (more academic education) had higher IQ at later ages than those who had the same tested IQ at age 11 but who for purely institutional reasons (e.g. shortage of places in their locality) went to the less academic 'secondary modern' schools.

Same effect. No gains in g will be observed. Likewise, no gains in such highly g loaded tests as reaction time and inspection time will be found. Such gains in speed are also not present when Flynn effect raw score gains are observed.

Ad numbering of houses:

In Prague (CZ), we have both types. A consecutive one and a "descriptive" one which is related to the time of building.

http://www.abs-praha.cz/web/obr/.../obr/ 122380.jpg

The small blue table is consecutive, the red one descriptive

"IQ from 3 to 21 years appears to be quite stable and achievement at 21 years is predicted about as well by the IQ estimate at 3 years as it is by IQ at 21 years."

This looks like a freak result. Most studies of early childhood IQ show very low correlations with later IQ.


"No gains in g will be observed."

Since g is not observable, this seems a safe prediction.

Most studies of early childhood IQ show very low correlations with later IQ.

Most studies use poor methods. Habituation typically does make such predictions. Mackintosh (p 57):

There is, however, one striking and important exception to this general failure to find early predictors of later IQ. The correlation between measures of habituation to a novel stimulus taken in the first year of life and IQ scores at age 5-7 is in the range 0.40-0.50 (see reviews by Bornstein and Sigman, 1986; McCall and Carriger, 1993), and some later studies have reported correlations of the same value between infant habituation and IQ scores out to age 10-12 ( Rose and Feldman, 1995).

... nor does it imply that IQ increases as people go through additional years of schooling.

I'm pretty sure regression and longitudinal and experimental (e.g. age cut-off time) studies do imply this. Though I also am doubtful about g gains.

I just looked at several papers that discuss the stability of intelligence.

Results:

The stability of general intelligence from early adulthood to middle-age
Intelligence, In Press, Corrected Proof, Available online 8 February 2007
Lars Larsen, Peter Hartmann and Helmuth Nyborg

The differential previous stability coefficients were: 0.85 for g; 0.79 for arithmetic; and 0.82 for verbal ability. With respect to absolute previous termstabilitynext term of the specific tests, we found a significant increase in verbal score (mean scores; 107.16, 116.52), but no change in arithmetic score. Problems associated with different concepts of previous stability, level of analysis and potential practice effects were discussed.

Overall, our findings provide support for the outcome of many other longitudinal studies, suggesting that general intelligence g shows high differential stability from early adulthood to middle-age. In fact, g measured in early adulthood predicts this very ability later in life with a precision that equals the reliability of the tests.

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The Stability of Individual Differences in Mental Ability from Childhood to Old Age: Follow-up of the 1932 Scottish Mental Survey
Intelligence, Volume 28, Issue 1, February 2000, Pages 49-55
Ian J. Deary, Lawrence J. Whalley, Helen Lemmon, J. R. Crawford and John M. Starr

Concurrent validity data are provided for the Moray House Test at age 11 (n=1,000) and age 77 years (n=97). The correlation between Moray House Test scores at age 11 and age 77 was 0.63, which adjusted to 0.73 when corrected for attenuation of ability range within the re-tested sample. This, the longest follow-up study of psychometric intelligence reported to date, shows that mental ability differences show substantial previous stability from childhood to late life.

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School achievement strongly predicts midlife IQ
Intelligence, Volume 35, Issue 6, November-December 2007, Pages 563-567
Ruth Spinks, Stephan Arndt, Kristin Caspers, Rebecca Yucuis, L. William McKirgan, Christopher Pfalzgraf and Elijah Waterman

The correlation between school achievement and WAIS-III FSIQ was r = 0.64, suggesting substantial life span previous stability in this relationship. Furthermore, elementary school achievement was substantially correlated with occupational status and household income at midlife. These findings suggest that standardized school achievement data is a useful measure of premorbid IQ.

In summary the current report shows a moderate to high correlation between school achievement and IQ further substantiating the previous stability of IQ over time despite a wide variety of potential intervening factors. More significantly, grade school standardized school achievement test scores appear to be a reasonable proxy measure for premorbid ability in a psychiatric population; providing a useful tool to psychiatric clinicians and researchers.

Vantage writes: "Flynn went to the extreme of inventing a magical relationship between the environment and genes and accompanied it with equations showing his idea to be possible, but it was entirely imaginary"

Feel like backing up that claim? The Flynn-Dickens model is not based on "magic" but on science. The idea that environment acts as a multiplier on genes has a great deal of explanatory power-- it explains the Flynn Effect as well as the twin studies. Flynn supports it quite well in his most recent book. What's your qualm with it, specifically?

Stephen Ceci had a list of these kinds of things (e.g exogenous changes in schooling resulting in an IQ change): "Schooling, Intelligence, and Income"

ben:

Feel like backing up that claim? The Flynn-Dickens model is not based on "magic" but on science.

Sorry, it is based on an invention that has not been demonstrated as factual. Even Flynn admits this.

The idea that environment acts as a multiplier on genes has a great deal of explanatory power-- it explains the Flynn Effect as well as the twin studies. Flynn supports it quite well in his most recent book. What's your qualm with it, specifically?

Can you cite sources that show any environmental factor that acts as a multiplier? As you know, Flynn has not cited any but you have accepted what he has imagined as a fact. Flynn has been quite clear in stating that he does not know what has caused the instability in test scores. In chatting with him, I found him to be honest, bright, and willing to admit when he is guessing. I asked him what portion of the IQ gains he has seen are g loaded. After repeating his thoughts about history as relating to testing, he admitted "I don't know." I asked the same question to John Raven and all he was willing to say is that people are getting better at solving abstract problems. As for g, he would not claim any gains.

Sorry, it is based on an invention that has not been demonstrated as factual.

The main alternative to it (that g is a quantitative aspect of brain physiology) hasn't been demonstrated as factual either.

I don't see why you jump to the conclusion, then, that Flynn's hypothesis is a "magical" invention.

Sorry, it is based on an invention that has not been demonstrated as factual.

The main alternative to it (that g is a quantitative aspect of brain physiology) hasn't been demonstrated as factual either.

Your response is a non sequitur. The invention in question is the magic multiplier. Psychometric g is not an alternative. There is virtually no debate among scholars that intelligence consists of g and a few narrow abilities (which account for virtually no external validity). There is agreement that the variance in intelligence consists of both genetic and environmental factors. The disagreements are over magnitudes and mechanisms.

I don't see why you jump to the conclusion, then, that Flynn's hypothesis is a "magical" invention.

The Dickens-Flynn magic multipliers is an invention that has not been shown to exist. In fact, if it existed, adoption studies would have turned out differently. Massive intervention, including adoption does not alter adult intelligence. Flynn does not attempt to explain the things that show that his model is wrong (as expected). The fact is that all environmental influences combined account for 20% or less of the total variance in intelligence.

Flynn does not have a credible explanation for environmental factors that account for the huge IQ difference between Ashkenazi Jews and other groups. Any reasonable model must account for every observed between-group difference. It needs to explain why Asians are smarter than Caucasians, but not smarter than Ashkenazi Jews and why 50/50 hybrids have IQs that are midway between the means of their two population groups, even when they share environments with adoptive families that do not share that mixture.

Every finding to date shows that IQ is about 80% heritable in adults. The argument that there are environmental effects that hide and appear to be genetic simply does not stand close scrutiny and has never been demonstrated. The argument is no different than one that asserts the properties of an invisible god.