# Questions on _g_ and intelligence

Nereid
Staff Emeritus
Gold Member
Tigers2B1 said:
I don’t know --- 12 more pages of questions??
Mon ami Tigers2B1, pardonnez-moi, tu et si mignon, mais semblez si stupide! Have you not been reading the posts here? :grumpy: Can you not count the number of times that hitssquad and Mandrake have given conflicting answers, to the same simple questions??

No, I have a part-time job stomping out crop circles for The National Enquirer you know. Plus, my cranium so big it has to be wheeled around on a tricycle --- so just give me time.

Tigers2B1 said:
Mandrake, you ever watch TV Land? On the TV Land channel there’s a program call Columbo, which features a private detective who catches his bad guy by simply using long lists of seemingly innocent questions – Columbo always seems confused --- in need of help. Then, near the end of the show, Columbo has this Got-Ya Moment when the ‘bad guy’ slips up on an answer to one of his voluminous questions.

Well, our Nereid is forever like Columbo – except he never has that Got Ya Moment.

For those unfamiliar with Columbo (but know Nereid) – I’ve linked this site ---

http://www.tvtome.com/tvtome/servlet/ShowMainServlet/showid-1011/Columbo/ [Broken]
This is ALL Nereid ever does for something that she has the inability to disprove. The infamous watermelon tactic as shown here:

Last edited by a moderator:
Nereid
Staff Emeritus
Gold Member
Mandrake said:
Nereid said:
Mandrake said:
Nereid said:
Mandrake said:
Intelligence appears to have at least some negative correlation with parity.
How much (range)? How extensively has this been tested?
I don't know. It is something that I have seen mentioned in various books and papers as part of the discussion of within family variance. Unfortunately, Jensen's books are rather poorly indexed (unlike The Bell Curve) so it is always difficult to find material in them.

Miller says that the levels of testosterone that children are exposed to may be related to parity. Presumably he meant the intrauterine environment.

Searching my files didn't work. The problems involve multiple meanings of the term "parity" and the difficulty in removing "disparity" from the search.
This is another of my questions that hasn't yet been answered (so I'm repeating it).This is another of my questions that hasn't yet been answered (so I'm repeating it).
Have you attempted to answer the question with the help of a search engine? It may be difficult, for the reasons I gave in my prior message. The topic is discussed in the literature, but is tedius to locate by searching. It was addressed in Storfer's book Intelligence and Giftedness, but does not appear in the index. The same is true with the other books I have. Most are not throughly indexed.
Let's see why this might be important.

Suppose there are two population groups, one in which all the children are only childs, the other in which every family has exactly two children. Suppose the 'parity effect' is very simple, the second child has a _g_ which is 1$$\sigma$$ below that of the first child (and first children in both groups have exactly the same _g_, on average).

If nothsuR, a well-known, if somewhat controversial, psychometrican, measures the average _g_ of children in each group, controlling for all the environmental variables she knows about (but not parity), what will she find? That the second group has an average _g_ 0.5$$\sigma$$ lower than that of the first group.

Now, suppose this 'parity effect' was only discovered after the MN study was completed (and Burt long since dead); how should honest, good scientist psychometricians respond?

So, let me repeat my question, and amplify: what is the size and nature of the 'parity effect'? In which countries has it been studied? When was the first case of it being characterised (close to the contemporary consensus view)? To what extent have historical data been reanalysed to account for this effect?

Last edited:
Nereid
Staff Emeritus
Gold Member
BlackVision said:
This is ALL Nereid ever does for something that she has the inability to disprove. The infamous watermelon tactic as shown here:

Thank you for your insightful and perceptive contribution to the nature of the scientific method BV.

Nereid said:
In which countries did Cattell do his research?

Nereid said:
In which countries did Cattell do his research?
You see this? See this is the difference between you and real scientists. Actual scientists do not expect their opponents to do their research. If you wanted to find out where Cattell did his research, why would you ask your opponent instead of finding out yourself? Now I trust you've read many scientific statements by scientists that attempt to refute one another. Do you ever see them doing this? Or do you see them try to present their own evidence and attempt to counter with statements. Yes statements not questions. I know this is not something you're used to but this is the common way in one carries a debate. Presenting evidence. In which it is something you rarely do. You can not win a debate this way.

Tom Mattson
Staff Emeritus
Gold Member
BlackVision said:
You see this? See this is the difference between you and real scientists.
Knock it off right now. If you don't want to answer the question, then don't answer it.

Nereid said:
So, let me repeat my question, and amplify: what is the size and nature of the 'parity effect'? In which countries has it been studied? When was the first case of it being characterised (close to the contemporary consensus view)? To what extent have historical data been reanalysed to account for this effect?
The entire contribution from all environmental causes, plus all errors, has a variance in the range of 20% to 30% (depending on age). The parity effect is quite small. If you are interested in finding the numerical value, I gave you a good reference. Please read Storfer's book. It will not take you any longer to find it that it would take me to find it.

If the other questions are interested enough to you that you actually want to know the answers, I trust that you can find them via the same mechanisms that I would use. If you take the time to look them up, I hope you will share your findings with the rest of us.

Nereid
Staff Emeritus
Gold Member
Mandrake said:
The entire contribution from all environmental causes, plus all errors, has a variance in the range of 20% to 30% (depending on age). The parity effect is quite small.

Just so that I'm quite clear though:
- this 20-30% 'environmental contribution + all errors' refers only to the US; per Jensen, insufficient work has been done to characterise these contributions - size and nature - in other countries
- 'environmental contribution' does not include factors such as illness, (head/brain) injury, 'drug taking', etc (more later)
- 'environmental contribution' does not include age (or, perhaps more accurately, _g_ is adjusted to include the observed, average age-related decline in general mental capabilities ... at least in the US); specifically, possibly irreversible declines (or advances) in _g_ due to 'lifestyle choices' are not included in the 'environmental causes'
- the 20% to 30% does include (an unquantifiable?) average 'practice effect'.

Nereid
Staff Emeritus
Gold Member
Mandrake said:
If the other questions are interested enough to you that you actually want to know the answers, I trust that you can find them via the same mechanisms that I would use. If you take the time to look them up, I hope you will share your findings with the rest of us.
Thanks for the comment.

What I was hoping for was access to an expert, who can quickly point a novice to online material which presents good, neutral summaries of the current state of the findings of researchers, much as many PF members do for those who enquire with physics, astronomy, etc questions.

Nereid
Staff Emeritus
Gold Member
Summary, (some) results so far

One of the things I am trying to get a better understanding of is the 'systematic errors' (to use the language of physics) that need to be accounted for - or at least identified - when reporting estimates of _g_ (or IQ) from a test given to a subject (or estimates from a meta-analysis of the reported results from many studies).

So far, thanks to Mandrake and hitssquad, I have learned that it's quite difficult to get a clear understanding of these systematic effects. Partly this seems to be because much of the research is reported in terms of correlations, and accurately translating these results into (say) 'IQ points', or 'delta _g_, measured in terms of some population standard deviation' is nigh impossible, and partly because the researchers have tried to control the test environment so as to avoid as many systematic effects as they could think of (so they don't test people who are obviously drunk, or ill, for example).

While I've not yet followed up on all the material which Mandrake and hitssquad have posted (and if it's not available online, I won't be able to), only two systematic effects appear to have been somewhat characterised: age and practice. The former seems it could be up to 30 IQ points (e.g. age 70 person vs age 20 person), the latter maybe 1 SD.

Nereid
Staff Emeritus
Gold Member
Intention, and its effect on an estimate of an individual's _g_

or, a person is not buckyball!

While I don't think I've seen, or taken, any of the highly g-loaded tests (e.g. matrix relations), I imagine they take the form of a time-limited multiple-choice questionnaire.

It may be difficult to do 'better' in such a test simply by consciously wanting to do as well as one could, but it's certainly easy to do worse through conscious intent! For example, one could simply choose an answer at random. I'm told there's a whole global industry called 'sports psychology', which (among other things) seeks to give the sportsperson the best possible 'frame of mind' for their competition, event, or whatever. Hitssquad has told us that there is a well-known, significant 'practice effect' wrt _g_; I wonder if there is an equivalent to the sporting 'psyched to win'?

In sports you can certainly be 'psyched to lose', and you may be very conscious of some aspects of this (e.g. fear); maybe you could also be quite unconscious of an attitude or 'mental state' (sports psych speak) that predisposes you to lose (or do less than your best). Is there some equivalent wrt taking IQ tests? To what extent has this been studied?

Now, a reader may think "what a stupid question! why on earth would anyone *want* to do less than their best in an IQ test?!" To some extent this objection is irrelevant; the point is that when researchers give tests to subjects, they assume the subjects will be trying their best; from another angle, it's misplaced - for example, if your personality predisposes you to poorly in 'IQ test environments' (e.g. fear), you may not be aware that (at some level) you are 'wanting' to do less than your best.

One-stop intellectual resources for differential psychology students

Nereid said:
quickly point a novice to online material which presents good, neutral
The request as stated cannot be honored. To my knowledge, techniques have not yet been developed to objectively quantitatively measure in academic material the traits good and neutral.

summaries of the current state of the findings of researchers
The most thorough review of the most broadly professionally-accepted findings regarding the g factor is Arthur Jensen's 1998 book The g Factor. It is available online for a subscription fee (monthly, quarterly, and yearly subscriptions are available; the cost for the yearly subscription at the current discount rate works out to 30 cents USD per day).

The most thorough review of the most broadly professionally-accepted findings regarding the presence within the United States of bias in mental testing is Arthur Jensen's 1980 book Bias in Mental Testing. It is not available online.

Last edited:
Nereid
Staff Emeritus
Gold Member
The request as stated cannot be honored. To my knowledge, techniques have not yet been developed to objectively quantitatively measure in academic material the traits good and neutral.

So, how about 'good' as in 'well-written, easily readable by an non-specialist', and 'neutral' as in 'presents both mainstream views of the field as well as alternative views and critiques from related fields'. Perhaps an example might help: within astronomy and cosmology, such a paper would cover not only the concordance models (including dark matter and dark energy/quintessence/cosmological constant), but also MOND, and even plasma cosmologies.

Within the sub-discipline of intelligence psychometrics, is there a tradition of review papers?

A note to the reader of The g Factor

Nereid said:
Nereid said:
quickly point a novice to online material which presents good, neutral
To my knowledge, techniques have not yet been developed to objectively quantitatively measure in academic material the traits good and neutral.
So, how about 'good' as in 'well-written, easily readable by an non-specialist'
Those are not quantities.

Jensen describes The g Factor in its Preface as readable by "typical ... college graduates":

• A NOTE TO THE READER

Although much of the material in this book is admittedly, though unavoidably, at a fairly difficult conceptual level, I have tried to present it in such a way that it can be understood not only by specialized readers with a background in psychology, psychometrics, statistics, or behavioral genetics, but by any interested persons of whatever educational background whose reading comprehension is up to the level of what I presume is typical of college graduates. I had thought of providing a glossary of the more specialized terms, but discovered that nearly all of the entries I would have included are given quite adequate definitions in the Random House Unabridged Dictionary (Second Edition, 1993).

If you would like to judge for yourself whether the book suits your standards, Matt Nuenke has published http://home.comcast.net/~neoeugenics/jen12.htm in its entirety on his website.

Nereid said:
and 'neutral' as in 'presents both mainstream views of the field as well as alternative views and critiques from related fields'.
Those also are not quantities.

I do not recall ever having read any academic publication by Jensen that did not include critiques and alternate views. Chapter 5 of The g Factor is devoted to "challenges to g," and Bias in Mental Testing is itself composed largely of critiques and responses to those critiques.

Last edited by a moderator:
Nereid said:
Just so that I'm quite clear though:
- this 20-30% 'environmental contribution + all errors' refers only to the US; per Jensen, insufficient work has been done to characterise these contributions - size and nature - in other countries
Since this same question appears in many of your messages, I previously noted that I will not attempt to research it each time it is asked. The value of h^2 has been researched and reported on by psychometricians from various countries. To the best of my knowledge, there are data sets from a number of countries that have been evaluated and reported. The comments in The _g_ Factor have not been restricted to findings reported in the United States, nor to research conducted by US scientists.

- 'environmental contribution' does not include factors such as illness, (head/brain) injury, 'drug taking', etc (more later)
The above statement is incorrect. These are micro environmental factors. Macro environmental factors involve social interactions; they have a near zero presence after age 17.

- 'environmental contribution' does not include age (or, perhaps more accurately, _g_ is adjusted to include the observed, average age-related decline in general mental capabilities ... at least in the US); specifically, possibly irreversible declines (or advances) in _g_ due to 'lifestyle choices' are not included in the 'environmental causes'
Psychometric data is usually restricted in such a way as to eliminate variations that would skew the data of interest. Age is a factor in many psychometric studies and is almost always discussed in the papers. It would be silly to pretend that age related factors have no relevance to psychometric studies.

- the 20% to 30% does include (an unquantifiable?) average 'practice effect'.
Most serious psychometric research is now reported in terms of _g_. Practice can change the _g_ loading of a conventional paper and pencil test, so that variable has to be accounted for. Passive measures of _g_ by RT and electroencephalography do not show a practice effect, but these studies usually include a familiarization phase, in which the test subject becomes familiar with the test procedure. All of this is explained in detail in The _g_ Factor.

Nereid said:
While I don't think I've seen, or taken, any of the highly g-loaded tests (e.g. matrix relations), I imagine they take the form of a time-limited multiple-choice questionnaire.
The most highly _g_ loaded standard IQ test is the Raven's (there are three tests for different levels). The appropriate method of administering this test is with no time limit. Sometimes time limits are used and do not degrade the test, if the time is generous. When time limited tests are used, the _g_ loading necessarily decreases as the time limit is shortened. This is because _g_ loading is a thinking relation. As time becomes more and more important, the _s_ loading increases. People who already have knowledge of the answer can call it up faster than those who have to think about it.

Arguably the most central of all IQ tests is the WISC, which is not a group test. It must be administered by a psychologist; some parts are timed and some are not.

For example, one could simply choose an answer at random.
That could be done with some tests and not with others. Tests administered to one person by one psychologist are not subject to such guessing. The test administrator would quickly determine that the test subject was not being cooperative and would stop the test. Given the high dollar cost of such tests, someone would be very upset with this outcome.

In sports you can certainly be 'psyched to lose', and you may be very conscious of some aspects of this (e.g. fear); maybe you could also be quite unconscious of an attitude or 'mental state' (sports psych speak) that predisposes you to lose (or do less than your best). Is there some equivalent wrt taking IQ tests? To what extent has this been studied?
There has been a good bit of study of testing errors and factors that may influence scores. Much of Bias in Mental Testing is devoted to this topic. It was necessary to evaluate this subject in order to demonstrate that it was not the cause of blacks scoring lower than any other population group. Of course the same concern exists with respect to the differences between all other population groups, but political pressure applies only to blacks. Sophisticated analysis of the tests can show such important factors as rank order difficulty. If someone takes a test and answers correctly below a given level of difficulty and then begins to answer incorrectly when the difficulty is higher, the test is probably doing its job. If he misses easy questions with an equal frequency to mid-level or hard ones, he is obviously trying to skew the results downward.

Nereid
Staff Emeritus
Gold Member
'parity', or 'family size and birth order'

Mandrake said:
Have you attempted to answer the question with the help of a search engine? It may be difficult, for the reasons I gave in my prior message. The topic is discussed in the literature, but is tedius to locate by searching. It was addressed in Storfer's book Intelligence and Giftedness, but does not appear in the index. The same is true with the other books I have. Most are not throughly indexed.
I spent a fair bit of time searching the internet for results of good research into the size of the 'family size' and 'birth order' effects on _g_ (or intelligence).

I found that:
a) research seems to have been done only in countries whose economies are service-based (e.g. US, western Europe)
b) findings have been confusing and apparently contraditory - some research found a clear effect, some found none
c) the research protocol has a big impact on what the results are; e.g. across a population (at one time) vs across time (following a clearly defined group)
d) none of the sources I found online gave quantatitive results (e.g. x IQ points, with an experimental error of +/- y); plenty talked about 'the larger the family size, the lower the average IQ', or 'the more older siblings, the lower the average IQ'.

Nereid
Staff Emeritus
Gold Member
languages, language fluency, and _g_

Another area I researched was the relationship between language fluency and _g_ (or 'intelligence', or 'IQ'). I was interested in this because one's ability to develop a 'mother tongue' fluency in a (spoken) language becomes dramatically different for all but a fortunate few once one is past puberty. This suggests that there is some deep biological process at work in the brain, perhaps related to the processes that give rise to _g_?

I couldn't find anything! Apparently Jensen, Rushton, even the founders (Binet, Spearman) haven't researched this at all!!

Now, I'll be the first to admit that my research has been purely online, and that there could well be a veritable cornucopia of research results that I didn't find.

What I'm looking for is any differences in the estimated _g_ of those who are at least bilingual from their earliest childhood vs those who are monolingual, or who acquired a second language essentially post-puberty. I'm referring entirely to oral capability; literacy is a different dimension which I will explore in a later post.

Nereid
Staff Emeritus
Gold Member
_g_ and literacy

The extent to which an individual's estimated _g_ is related to that individual's literacy (ability to read and write in their 'mother tongue') is a third area I researched (online).

The first thing I found was that such research would be difficult, if not impossible, in service-based economies; they all have 'universal education', and those who do not achieve functional literacy by adolescence (or puberty) are quite likely to have already known low _g_ (e.g. Down's syndrome, physical injury, severe drug addiction, mental illness).

Next, it seems that what little research has been done among non-literate adults, in agriculture-based economies for example, suffers from heavy biases, e.g. Rushton and Lynn's work.

Finally, there seems to have been no work done to estimate the relative _g_ impact of different writing systems (e.g. logographic vs alphabetic); indeed, the conclusion from studies which appear to show that the populations in Japan, Korea, China, Hong Kong, Singapore, Taiwan etc have a higher average IQ seems to have been 'they are genetically superior wrt _g_' rather than 'literacy based on a logographic writing system results in higher estimated _g_'

Nereid said:
The extent to which an individual's estimated _g_ is related to that individual's literacy (ability to read and write in their 'mother tongue') is a third area I researched (online).
Literacy is presumably intended to mean "education." I have not found anything that suggests that education can raise or lower _g_. The _s_ loading of some tests is probably increased by education and may cause some measurable increase in IQ.

The first thing I found was that such research would be difficult, if not impossible, in service-based economies; they all have 'universal education', and those who do not achieve functional literacy by adolescence (or puberty) are quite likely to have already known low _g_ (e.g. Down's syndrome, physical injury, severe drug addiction, mental illness).
Within any society, there are people who get more or less education as a matter of circumstance. Not every high _g_ person is highly educated. We have discussed the cases of the people who were featured by Esquire as being among the smartest in the US. Two of the 4 hold doctorates. Two (to the best of my knowledge) hold no college level degrees. At least two are living at a level that may be fairly categorized as impoverished. Among those not listed, I know a good number (in Hi-Q societies -- way above Mensa) who have not earned college degrees. My point is that intelligence is not caused by education.

Next, it seems that what little research has been done among non-literate adults, in agriculture-based economies for example, suffers from heavy biases, e.g. Rushton and Lynn's work.
If one is studying sub-Saharan Africans, the cultures will be have little literacy and will be non-industrial. What are the "heavy biases" that you have found in their work?

Finally, there seems to have been no work done to estimate the relative _g_ impact of different writing systems (e.g. logographic vs alphabetic); indeed, the conclusion from studies which appear to show that the populations in Japan, Korea, China, Hong Kong, Singapore, Taiwan etc have a higher average IQ seems to have been 'they are genetically superior wrt _g_' rather than 'literacy based on a logographic writing system results in higher estimated _g_'
I don't know how much work has been done with respect to language. It is something to study and may have been studied. Brand has written a number of comments about deaf people, which I think may be related. For example:

... deaf children have entirely normal levels of performance on gf tests despite having missed much of the supposedly enriching and stimulating world of language and verbal communication; but, especially in childhood, they do have lower scores on gc tests requiring knowledge of language (Braden, 1994). In both cases, the tests are valid; but one type, gc, requiring normal verbal skills, registers - quite properly, and indeed quite fairly - a real handicap.(18)

... deaf children, despite their gross cultural deprivation, have no special problems with non-verbal tests that are well known as good measures of IQ.

Braden (op.cit.) especially considers the idea that minority children are handicapped in access to the ways of the 'dominant culture' - e.g. because their parents do not know it, do not like it, or anyhow cannot communicate it to their children; and thus that minority children will be deficient in the knowledge which is sometimes thought to be especially tapped by IQ-type tests. By such criteria, deaf children clearly have a massive handicap in accessing the 'dominant culture'; yet they have entirely normal levels of gf.

[Brand, C. (1996). The _g_ Factor: General Intelligence and Its Implications. Chichester, England: Wiley]

Nereid
Staff Emeritus
Gold Member
Thanks Mandrake.
Mandrake said:
Since this same question appears in many of your messages, I previously noted that I will not attempt to research it each time it is asked. The value of h^2 has been researched and reported on by psychometricians from various countries. To the best of my knowledge, there are data sets from a number of countries that have been evaluated and reported. The comments in The _g_ Factor have not been restricted to findings reported in the United States, nor to research conducted by US scientists.
This conflicts with what hitssquad posted earlier, at least as far as Jensen is concerned. Also, in my (limited) online research, I've found that the well-controlled, lab-based, large-scale work seems to have been done almost exclusively in just a few countries, and that none come remotely close to the US in terms of quantity. Further, there are few, if any, pieces of in-depth research done in countries which are predominantly agricultural, or even industrial.

Of course, generalisation to all countries, all of Homo sap. is pervasive (again, with the notable exception of Jensen); detailed explanations for why such generalisations are justified scant.
Nereid said:
'environmental contribution' does not include factors such as illness, (head/brain) injury, 'drug taking', etc
The above statement is incorrect. These are micro environmental factors.
I looked; no one seems to have attempted to study how estimates of _g_ would vary if the subjects were (for example) drunk (and quantify the effects by time and quantity of grog consumed).
Macro environmental factors involve social interactions; they have a near zero presence after age 17.
This statement seems to reflect research done in the US; there doesn't seem to be anything on these effects for people who reach adolescence at significantly different ages than US kids, nor who remain living with family (or an institution, e.g. priests, nuns) beyond adolescence.
Psychometric data is usually restricted in such a way as to eliminate variations that would skew the data of interest. Age is a factor in many psychometric studies and is almost always discussed in the papers. It would be silly to pretend that age related factors have no relevance to psychometric studies.
Quite. However, to repeat, my interest at present is systematic effects on estimates of an individual's _g_ obtained from a single test (or a series of tests done in one sitting). In this sense, your comment, while it may be accurate, is irrelevant.
Most serious psychometric research is now reported in terms of _g_. Practice can change the _g_ loading of a conventional paper and pencil test, so that variable has to be accounted for. Passive measures of _g_ by RT and electroencephalography do not show a practice effect, but these studies usually include a familiarization phase, in which the test subject becomes familiar with the test procedure. All of this is explained in detail in The _g_ Factor.
Jensen's? or Brand's?

I want to return to these 'passive measures', esp wrt the Flynn effect, but for now I merely note that few if any such detailed studies appear to have been done with folk other than young, literate urban adults in the US and a few other service-based economies. I also note that details of the research protocols - esp the extent to which pre-defined, double-blind ones are used, and non-manual measurement, are scanty (at least, I've not been able to find much online).

Nereid said:
Originally Posted by Mandrake
Since this same question appears in many of your messages, I previously noted that I will not attempt to research it each time it is asked. The value of h^2 has been researched and reported on by psychometricians from various countries. To the best of my knowledge, there are data sets from a number of countries that have been evaluated and reported. The comments in The _g_ Factor have not been restricted to findings reported in the United States, nor to research conducted by US scientists.

Nereid: This conflicts with what hitssquad posted earlier, at least as far as Jensen is concerned.
Jensen is a US scientist and has done most of his work in California, presently under the rule of an Austrian.

Also, in my (limited) online research, I've found that the well-controlled, lab-based, large-scale work seems to have been done almost exclusively in just a few countries, and that none come remotely close to the US in terms of quantity.
The United States leads all countries in scientific research. Look at the Nobel Prizes in the sciences before and after WW2. There was a sudden shift from Germany to the US. I can't think of any reason to expect another country to do more research in psychometrics than would be the case in astronomy or particle physics.

Further, there are few, if any, pieces of in-depth research done in countries which are predominantly agricultural, or even industrial.
Huh? What is the point of that comment? It applies quite well to magnetic data storage, DNA research, space travel, and lasers. I don't get it. I think you have made similar comments before. Why???

I looked; no one seems to have attempted to study how estimates of _g_ would vary if the subjects were (for example) drunk (and quantify the effects by time and quantity of grog consumed).
Is there some reason why psychometricians should be looking at temporary phenomena? If someone goes to sleep, I would bet that his score on an IQ test would not be high, but that it would not be meaningful either. My prior comment was in reference to permanent environmental factors that relate to the micro environment. I could not believe that you were really asking about temporary impairment. Do you think that there is scientific research concerning human running ability? I assume there is. If so, would it be your concern that they should study runners with broken legs, drunk runners, and runners who have not eaten for six days?

Mandrake: Most serious psychometric research is now reported in terms of _g_. Practice can change the _g_ loading of a conventional paper and pencil test, so that variable has to be accounted for. Passive measures of _g_ by RT and electroencephalography do not show a practice effect, but these studies usually include a familiarization phase, in which the test subject becomes familiar with the test procedure. All of this is explained in detail in The _g_ Factor.

Jensen's? or Brand's?
As a convention, I assume that the reader understands that Jensen, A. R. (1998). The g factor: The science of mental ability. Westport, CT: Praeger, is the standard textbook in the field of psychometrics. When I wish to reference Brand's book, I do it by writing The _g_ Factor: General Intelligence and Its Implications.

I want to return to these 'passive measures', esp wrt the Flynn effect, but for now I merely note that few if any such detailed studies appear to have been done with folk other than young, literate urban adults in the US and a few other service-based economies.
This comment is not correct. Passive testing has been done in the US, Australia, New Zealand, England, and probably Germany and other countries. The IQ ranges of subjects reported by Jensen starts at around 40. Since retardation starts at 70, I do not agree that all of these subjects were literate. The service based economy thing is spurious. If you must keep including it, please explain your reason each time. Science is not dependent on whether the researchers live in a service based economy or not. I should add that you have not established that your claim is even true. I doubt that some of the contributing countries have service based economies. Would you please give us a complete list of the countries that have service based economies and some sound and verifiable information that shows your list is correct?

I also note that details of the research protocols - esp the extent to which pre-defined, double-blind ones are used, and non-manual measurement, are scanty (at least, I've not been able to find much online).
I have no idea what you are reading. The Intelligence 32-4 and 32-5 arrived in my mailbox today. A quick look through them (and any past issues) shows that your observation is false. Since you think that the US is alone in this area of science, you might be interested in the article in 32-5 by a large team of Chilean scientists who studied brain volumes, IQ, and SES. The paper includes a detailed description of the methodology and a massive presentation of the data collected, along with brain images. The subjects included both high and low SES people of both sexes. "Independently of sex, brain volume was the only brain parameter that contributed to explain IQ variance."

Nereid
Staff Emeritus
Gold Member
Mandrake said:
Literacy is presumably intended to mean "education." I have not found anything that suggests that education can raise or lower _g_. The _s_ loading of some tests is probably increased by education and may cause some measurable increase in IQ.
Sorry I wasn't clear; I meant basic literacy, as opposed to 'illiteracy'; I specifically do not mean 'education'. IOW, basic literacy means being able to read simple signs (e.g. "STOP", "Walk"), numbers, and in the western tradition is what most kids reach by kindergarten. AFAIK, there are hundreds of millions, possibly billions, of adults who are illiterate; for example, despite years of propoganda, it seems that a significant proportion of the adult population in China's 'countryside' are illiterate or barely literate.
If one is studying sub-Saharan Africans, the cultures will be have little literacy and will be non-industrial. What are the "heavy biases" that you have found in their work?
It's not only there; the majority of such folk are in Asia, particularly in China and India. In fact, it's probably less than 50 years - not even two generations - since the vast majority of Homo sap. were living in economies that were primarily agricultural (of course, it's much longer for the US and western Europe, but they comprise <15% of the world's people).

I am getting to the heavy biases; patience please.

Nereid
Staff Emeritus
Gold Member
Mandrake said:
Jensen is a US scientist and has done most of his work in California, presently under the rule of an Austrian.

The United States leads all countries in scientific research. Look at the Nobel Prizes in the sciences before and after WW2. There was a sudden shift from Germany to the US. I can't think of any reason to expect another country to do more research in psychometrics than would be the case in astronomy or particle physics.

Huh? What is the point of that comment? It applies quite well to magnetic data storage, DNA research, space travel, and lasers. I don't get it. I think you have made similar comments before. Why???
If all that you have is stamps (correlations), and the only stamps you have collected are from a few countries, how do you know that the rest of the world has stamps, or that they aren't made of diamond and not paper? How can you be confident that the biological correlates are the same for people whose life experiences are significantly different from those who you have studied?
Is there some reason why psychometricians should be looking at temporary phenomena? If someone goes to sleep, I would bet that his score on an IQ test would not be high, but that it would not be meaningful either. My prior comment was in reference to permanent environmental factors that relate to the micro environment. I could not believe that you were really asking about temporary impairment. Do you think that there is scientific research concerning human running ability? I assume there is. If so, would it be your concern that they should study runners with broken legs, drunk runners, and runners who have not eaten for six days?
To reiterate the point about correlations, if you have no idea how 'temporary phenomena' affect the arbitrary constructs you are studying, how can you tell that there aren't 'temporary phenomena' which are systematically biassing your results? Further, if you hypothesise that _g_ is something to do with brain processes, don't studies of impairment tell you a great deal? AFAIK, this is just how much progress has been made into the neurophysiology (?) of language.

To give a possibly irrelevant example; several decades ago smoking was widespread, and even then nicotine was understood to have neurological effects. Presumably Jensen et al tried very hard to control for this 'temporary phenomenon', but given the near ubiquity of the social habit, the persistence of the drug (and metabolites) in the brain, and people's imperfect veracity when it comes to reporting such habits, are you confident that the effect of smoking as a temporary phenomenon has been completely eliminated from old data?
This comment is not correct. Passive testing has been done in the US, Australia, New Zealand, England, and probably Germany and other countries.
All of which are service-based economies (see below)
The IQ ranges of subjects reported by Jensen starts at around 40. Since retardation starts at 70, I do not agree that all of these subjects were literate.
That's not my point (again, apologies for not being clear); the subjects have included few, if any, 'average' adults who just happened to be illiterate.
The service based economy thing is spurious.
Au contraire, mon ami! As I said above, extrapolating *correlations* found in one set of circumstances is contraindicated in good science; if all you have is correlations (and our discussion of the state of play wrt neuroscience and theory certainly seems to indicate that we've little else today), you need extremely good reasons to declare validity beyond the domains within which you obtained them.
If you must keep including it, please explain your reason each time. Science is not dependent on whether the researchers live in a service based economy or not.
It's not where the researchers live so much as where the *subjects* live.
I should add that you have not established that your claim is even true. I doubt that some of the contributing countries have service based economies. Would you please give us a complete list of the countries that have service based economies and some sound and verifiable information that shows your list is correct?
How about The World Bank? The link is to a page from which you can get employment by sector ('primary' = agriculture, fishing, animal husbandry, and mining; 'secondary' = industry; 'tertiary' = services), and also gives breakdowns by gender. The panel at the left allows you to navigate through a huge wealth of data.

Employment by sector (%; male/female; primary, secondary, tertiary):
US: 3/1; 32/12; 65/87
Australia: 6/3; 30/10; 64/87
New Zealand: 12/6; 32/12; 56/82
UK: 2/1; 36/11; 62/88
Germany: 3/2; 44/18; 52/80

Thailand: 50/48; 20/17; 30/35

Of course, these data need to be read in combination with the extensive notes; in particular, the agricultural sector for developing countries tends to be larger than the data would otherwise appear to indicate. On these World Bank pages, you will also find sector data, by economic activity (cf employment).