I saw this was posted to Slashdot, so if you wonder where the flamewar is at... (the Slashdot population is on average rather 'empirically egalitarian')

I think this is a 'meta-analysis', i.e. no new data.

Some reports suggest it is based mainly on studies of university students. Since students are not a representative sample of the population, higher male IQ among students might just mean that males need a higher average IQ to get into university, to offset their relative laziness in school. (Or to put it another way, girls work harder and therefore need a lower average IQ to succeed).

Lynn has been arguing for years that males have higher IQ, but has failed to convince other experts, such as Jensen. Jensen says (G Factor, p.532) 'the best available evidence fails to show a sex difference in g.'

Maybe this is a trait specific to certain populations, not a common one, because, if I recall correctly, in African Americans measured female IQs show a HIGHER average than male average IQs.
But maybe this all shows how much IQ is an environment dependent variable.

Also, standard IQ tests have a large section on spatial intelligence -- rotating diagrams in space and the like -- which the male brain on average is supposed to be better at. (I'm female and I have a lot of trouble with that part.) Is that by any chance where the puported 5-point difference is?

African Americans measured female IQs show a HIGHER average than male average IQs.

Jensen reviews the data and rejects this hypothesis in the g factor.

In any case, it's all averages. I'm still smarter than any guy I meet. ;)

The g-factor is usually factor analyzed from populations of 50-50 mixed gender, and thus by itself between-sex disparities are automatically mitigated. On the other hand, were one to extract a common g factor from, say, an exclusively male population, it would have more of a loading on male cognitive pecularities and a larger gender-gap (favoring males) would emerge on this dimension. This male-only derived factor, it is reasonable to assume, shows stronger correlations than mixed-gender g itself, with various life outcome measures.

David B says:


Jensen says (G Factor, p.532) 'the best available evidence fails to show a sex difference in g.'


Well, Nyborg, in his article in the tribute to Jensen book, claims that Jensen now agrees that there is a sex difference. Google will give you the PDF for tghe chapter.

BTW, Nyborg reports a similar difference between males and females. Slightly under 5 points.

"in African Americans measured female IQs show a HIGHER average than male average IQs."

I think generally speaking, k-12 school achievement is higher in girls than it is in boys and that may have something to do with motivation or the greater prevalence of learning disabilities among boys, although learning disabilities presumably only lower scores on certain subtests of IQ tests, not the whole test. So maybe motivation and learning disabilities are playing a role, although it's not obvious that the learning disabilities thing wouldn't show up just as much with whites as with blacks. I read that black girls from Detroit are four times as likely to go on to college as black boys which sounds like a motivation thing. A big difference between academic achievement and IQ scores might indicate motivational problems or learning disabilities but those things may lower IQ as well, just not as much as they lower academic achievement.

"higher male IQ among students might just mean that males need a higher average IQ to get into university, to offset their relative laziness in school. (Or to put it another way, girls work harder and therefore need a lower average IQ to succeed)."

It's not at all obvious why that is if males have more dominant personalities than females. If that were true, then one would expect that they would want to try harder to prove their superiority. Or it could go the other way if the schools are viewed as some sort authority to be challenged.

I guessing that the bottom 5 percentile of the population was underepresented in this study.

This skews the study to favour males.

Anon says:


I guessing that the bottom 5 percentile of the population was underepresented in this study


Ahhh, so you accept the claim that males show a larger SD than females.

I'm guessing that the male SD would have to be twice the female SD for the overrepresentation of males at the extreme to increase the male mean by approximately 5%.

doesn't it make intuitive sense that males would have a slightly higher average IQ than females? after all, it's the males who need to impress with more than just their genetically gifted looks.

"...after all, it's the males who need to impress with more than just their genetically gifted looks."

That takes only a slightly higher iq?
It always seemed to me like the female suppressed a few points to make herself more easily impressed.

terry says:


That takes only a slightly higher iq?
It always seemed to me like the female suppressed a few points to make herself more easily impressed.


All of this noise ignores the economics of the situation.

Every CC of brain matter costs, both to develop and to maintain.

If females are suppressing their intelligence for whatever reason, then any individuals that actually do away with the unneeded brain cells win, because of the lowered cost to build and maintain that brain power, so they can devote more resources to reproduction or start reproducing sooner. If that reduction in brain cells is heritable, then we have evolution in action.

Similarly, males will not maintain expensive brain power that is not necessary.

In a similar vein, because males and females actually have different problems to solve, vis-a-vis life histories and reproduction, you can expect differences in behavior and the underlying neural circuitry that drives behavior.

I don't know about other countries, but in the UK it is well-known that girls work harder (on average) in school, as shown by better results in regular assessment (coursework). Boys do relatively better in end-of-year exams, where they can cram for a week or so before the test to make up for their laziness during the rest of the year. Coursework now plays a larger part in overall achievement measures (qualifications) than it used to, with the result that girls have better average qualifications.

I speak as a lazy male: I am very glad that when I was at school the qualifications depended entirely on exams!

"I speak as a lazy male: I am very glad that when I was at school the qualifications depended entirely on exams"

well, speaking as a lazy female, I was more of the cram all night to pass variety and it worked best at times for me. OTOH, steady application weaves the info as warp and woof rather than a fleeting image bright from caffein.

"... males will not maintain expensive brain power that is not necessary"

There's such a thing as "unncessary brain power?

In high school, the best student in the class deliberately started doing poorly in math because she said "boys don't like girls who are good in math." I thought to myself, "pretending to be stupid makes you desirable?" How absolutely icky. Even the more boy-crazy girls seemed to think this inexcusably phony.
Perhaps she continued to live her little dim-wit lie and actually attracted just the man for her, He-who-hates-girls-that-are-good-at-math ...but,
how long do poor math skills render a girl irresistable?
If one accepts that average iq varies among races, one can't cherry pick--if races differ, then so can genders. I do tend to think, however, it is more of a difference in kind of intelligence, than quantity.

There is Nigerian woman scientist at NASA, who was responsible for an innovation. Her story was printed up in "Women of NASA". One of the office admins put her story and picture up on the bulletin board, unbeknownst to the self-effacing Nigerian lady. The other scientists, mostly men, came by and read about her and were quite impressed--they'd known nothing about her achievements since they don't read "Women of Nasa". Naturally.
http://quest.arc.nasa.gov/women/WON.html

btw, a World Book Encyclopedia from 1960, in the section on "women." (this was somewhat before feminism and pc)claimed that "iq tests show the sexes are equal in intelligence or that women are slightly superior." Whatever women were doing with that purported slight "superiority" of the 1950s, it will probably make no difference from what we do with our current slight "inferiority" if we just hang around like our poor girl described above, waiting for...what? Godot? or shall we say, Godesso?

Well, Nyborg, in his article in the tribute to Jensen book, claims that Jensen now agrees that there is a sex difference.

Yes, that is his current stance (or, it was last year, anyway). I'm sure it will be an issue at the upcoming ISIR conference. Also, Lynn presented much of his article there last year at the ISIR conference; if you google it, I'm sure you'll find the abstrats. And it is a review/meta analysis paper.

Also, standard IQ tests have a large section on spatial intelligence

They also have a large section on ``Verbal Intelligence." So, unless the analyses only used Raven's and Cattell's instruments, I doubt this is the case.

On the other hand, were one to extract a common g factor from, say, an exclusively male population, it would have more of a loading on male cognitive pecularities and a larger gender-gap (favoring males) would emerge on this dimension. This male-only derived factor, it is reasonable to assume, shows stronger correlations than mixed-gender g itself, with various life outcome measures.

This is surely a testable notion, but I have never seen anything of the sorts done, so would be wary to say it definitively untill I could see data indicating it.

Terry asks:


There's such a thing as "unncessary brain power?


Every part of an individual's body costs, to build and maintain.

The human brain absorbs something like 25% of our daily calorie intake and 20% or our daily oxygen intake. It is an expensive organ.

Given that each individual's real goal is reproduction (those that don't have lost the game and do not contribute their genes to the future), building more brain than is needed to do the job will reduce that individual's reproductive success when other individuals can and do get by with less.

Indeed, we might be seeing the result of exactly this tradeoff having been made in the past, with individuals derived from humans who have lived in Africa or the Pacific islands or regions near the Equator, where life is, on average, easier than elsewhere, having less 'intelligence,' on average, than others.

These arguments are the same ones that demonstrate that the old crap about humans only using 10% of their brains is exactly that. Any individual that expended that much growth time and energy building an organ to use only 10% of it will be out-reproduced by those that are more sophisticated in their use of time and energy.

"Given that each individual's real goal is reproduction"
Who said anything about everybody's "real" goal being reproduction? That is true of an animal, or an insect. Is it true of those with free will? We can say, I do not care to reproduce, I want to sit on a rock and think about the stars.
Reproduction is a major goal, generally speaking, but the "real" one? Some people's real goal is reduction. Besides, I'm not talking brain, I'm talking mind.
Even the wisest scientists do not know it all quite yet--too paraphrase Startrek: the human brain/mind will be going places in the future where no one has been before. And it will be doing it whether it is using 10% or 100% of its potential.

Terry says:


Who said anything about everybody's "real" goal being reproduction? That is true of an animal, or an insect.


I often wonder, when my poor castrated cat looks at me with those wise-looking eyes of his, is he damning me for what I did to him, or does he even realize?


Is it true of those with free will?


You are free to believe in that illusion, if you wish.


to paraphrase Startrek: the human brain/mind will be going places in the future where no one has been before.


Indeed, but it will be the brains of those individuals who are descended from those of us who bothered to reproduce.

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