How to prepare for the coming science of genetic racial variations, and a summary of the full case for the genetics of racial differences in intellige

[ksen]

Why would Sowell say that? It is known we aren't isolated enough to be actual candidates for race development by a long shot and the study of the genetics of intelligence hasn't even gotten past the array found in our capability for language which is somehow related to FOXP2.

The only way Sowell ethically or morally could say that is if he is suffering from blindness and selection bias disorder at the same time. I'm suspicious. Is he relying on intelligence testing among humans and phenotypology? If so. Explained.

Atta boy DrZoidberg​.

One need not believe that races are genetic before accepting the existence of the racial IQ gaps. Even for those who argue that races are merely cultural, the race-IQ gaps exist, and they are likewise victims of the extreme public taboo.

So it's really a cultural iq gap. Is culture genetic too?

 

[ApostateAbe]

And what do you make of the evidence that how well one does on these IQ tests (even as a child) is a better predictor of future financial income, job performance, birth out of wedlock, and involvement in crime than are an individual's parental socioeconomic status, or education level?

Could you please post where you hear IQ is a better predictor of financial income as opposed to parental socioeconomic status? Even Malcom Gladwell says that socioeconomic status is the best predictor of income.

And the studies I am finding relating IQ with financial gain are based upon "estimated" IQs of military individuals when they were teens without regard to socioeconomic status of parents.

I posted a figure from Herrnstein and Murray that proves the point. Malcolm Gladwell is a popular author associated with the blank slate theory but not a respected academic authority and most certainly not respected among intelligence researchers. Put up Malcolm Gladwell's correlations alongside against Herrnstein and Murray's comprehensive regression analyses.

 

[ApostateAbe]

One need not believe that races are genetic before accepting the existence of the racial IQ gaps. Even for those who argue that races are merely cultural, the race-IQ gaps exist, and they are likewise victims of the extreme public taboo.

So it's really a cultural iq gap. Is culture genetic too?

No. I said, "Even for those who argue that races are merely cultural...", but I am not one of them.

 

[Nice Squirrel]

Could you please post where you hear IQ is a better predictor of financial income as opposed to parental socioeconomic status? Even Malcom Gladwell says that socioeconomic status is the best predictor of income.

And the studies I am finding relating IQ with financial gain are based upon "estimated" IQs of military individuals when they were teens without regard to socioeconomic status of parents.

I posted a figure from Herrnstein and Murray that proves the point. Malcolm Gladwell is a popular author associated with the blank slate theory but not a respected academic authority and most certainly not respected among intelligence researchers. Put up Malcolm Gladwell's correlations alongside against Herrnstein and Murray's comprehensive regression analyses.

I was unable to access your data. Could you post a link to source study or cite the paper. I have access to nearly all scientific journals.

Also, do you a comment on the other links such as the twins study showing a correlation between environment and IQ test scores?

 

[ApostateAbe]

I posted a figure from Herrnstein and Murray that proves the point. Malcolm Gladwell is a popular author associated with the blank slate theory but not a respected academic authority and most certainly not respected among intelligence researchers. Put up Malcolm Gladwell's correlations alongside against Herrnstein and Murray's comprehensive regression analyses.

I was unable to access your data. Could you post a link to source study or cite the paper. I have access to nearly all scientific journals.

Also, do you a comment on the other links such as the twins study showing a correlation between environment and IQ test scores?

Herrnstein and Murray's book was original analysis. You can find the full book online here:

https://lesacreduprintemps19.files.wordpress.com/2012/11/the-bell-curve.pdf

Parental SES most certainly affects IQ in young children (aged 7), and it is widely agreed among intelligence researchers that intelligence scores are most fluid and affected by the environment the younger they are and progressively get more heritable and stable as they age. That is part of points #14 and #16 of Mainstream Science on Intelligence.

 

[Nice Squirrel]

I was unable to access your data. Could you post a link to source study or cite the paper. I have access to nearly all scientific journals.

Also, do you a comment on the other links such as the twins study showing a correlation between environment and IQ test scores?

Herrnstein and Murray's book was original analysis. You can find the full book online here:

https://lesacreduprintemps19.files.wordpress.com/2012/11/the-bell-curve.pdf

How come I get the feeling that we are having a religious discussion as you keep pointing to your bible?

 

[ApostateAbe]

Herrnstein and Murray's book was original analysis. You can find the full book online here:

https://lesacreduprintemps19.files.wordpress.com/2012/11/the-bell-curve.pdf

How come I get the feeling that we are having a religious discussion as you keep pointing to your bible?

It is where the relevant analysis exists that answers your question. The data comes from NLSY79, analyzed by Herrnstein and Murray, and the analysis is presented in that book. But I don't suggest you read that book first. There is no Bible here. I suggest you start with Sarich and Miele's Race: the Reality of Human Differences.

 

[ksen]

So it's really a cultural iq gap. Is culture genetic too?

No. I said, "Even for those who argue that races are merely cultural...", but I am not one of them.

Then what is race in your opinion?

Currently there are two dogs sitting at my feet: a poodle and a basenji. Are those two dogs different races?

 

[ApostateAbe]

No. I said, "Even for those who argue that races are merely cultural...", but I am not one of them.

Then what is race in your opinion?

Currently there are two dogs sitting at my feet: a poodle and a basenji. Are those two dogs different races?

I would call them two different breeds. "Breed" normally applies to dogs, and "race" normally applies to humans, though Darwin used those words interchangeably in his writing. It is the same biological principle. "Race" is a population of humans with a tendency of gene frequencies, and a tendency of ancestry identified by geography, that is different from such tendencies of other populations.

 

[ksen]

So Appalachians would be a different race than Southern Californians?

 

[ApostateAbe]

So Appalachians would be a different race than Southern Californians?

I think so. Races are divisible all the way down to the individual, much like colors on a color spectrum are divisible all the way down to the minutest wavelength difference.

 

[Nice Squirrel]

How come I get the feeling that we are having a religious discussion as you keep pointing to your bible?

It is where the relevant analysis exists that answers your question. The data comes from NLSY79, analyzed by Herrnstein and Murray, and the analysis is presented in that book. But I don't suggest you read that book first. There is no Bible here. I suggest you start with Sarich and Miele's Race: the Reality of Human Differences.

You are sounding an awful lot like a Scientologist wanting me to believe only Hubbard's writings. Anyway, I see no IQ assessments in the NLSY79. In order for your (and the author's) claims to be valid they would have had to be given IQ tests.

 

[ApostateAbe]

It is where the relevant analysis exists that answers your question. The data comes from NLSY79, analyzed by Herrnstein and Murray, and the analysis is presented in that book. But I don't suggest you read that book first. There is no Bible here. I suggest you start with Sarich and Miele's Race: the Reality of Human Differences.

You are sounding an awful lot like a Scientologist wanting me to believe only Hubbard's writings. Anyway, I see no IQ assessments in the NLSY79. In order for your (and the author's) claims to be valid they would have had to be given IQ tests.

The NLSY79 collected military ASVAB scores. They are not quite the same as IQ tests, but they are highly g-loaded, meaning they highly correlate with Spearman's g (and all other intelligence tests, as they all positively correlate with each other). Lay critics may think that nothing counts as a measure of intelligence except IQ tests (which is typically a big concession given the ideological tendency of the lay critics), but intelligence researchers generally don't think that way.

 

[Nice Squirrel]

You are sounding an awful lot like a Scientologist wanting me to believe only Hubbard's writings. Anyway, I see no IQ assessments in the NLSY79. In order for your (and the author's) claims to be valid they would have had to be given IQ tests.

The NLSY79 collected military ASVAB scores. They are not quite the same as IQ tests, but they are highly g-loaded, meaning they highly correlate with Spearman's g (and all other intelligence tests, as they all positively correlate with each other). Lay critics may think that nothing counts as a measure of intelligence except IQ tests (which is typically a big concession given the ideological tendency of the lay critics), but intelligence researchers generally don't think that way.

The ASVAB test on items such as auto mechanics and 1970s electronics. These are not measures of intelligence. The ASVAB does not collect information on non-military bound individuals. Just like the other tests (PSAT, ACT) in your data do not collect IQ data. Call me a lay critic, but even I know that teens in the 1980s who took the college entrance exams were planning on going to college, and high scores indicate a readiness and interest in college. And those who did not take these exams where are they?

What it looks like you have is a self-fulfilling prophecy. Since you are throwing around the term, "lay critics" could you please tell us which credentials you have that make you an expert other than a lay interest?

 

[whichphilosophy]

I predict that it will be a decade before all the genes for intelligence are identified and found to vary significantly by race. First, I will explain how liberals and independents must prepare for this discovery. Next, I will explain how I know this discovery will happen.

Many xenophobic conservatives will happily accept this science, and they will use it in an attempt to justify any of a vast array of oppressive politics resurrected from before MLK: border restrictions, hiring discrimination, justice system inequalities, Jim Crow laws, lynch mobs, forced sterilizations, wars and genocides. They will pretend to be the champions of science, in contrast to the liberals who only deny and fight the science. But, rational liberals must accept the science even more than the conservatives (conservatives will accept only the science they like), and they must win independents to their side. It will be the social responsibility of liberals to lessen the chains and bloodspills of racial divides. They can do it with these talking points:

(1) RACES ARE SPECTRAL, not discrete, and most people belong to a mixture of races with an accompanying mixture of racial traits. Even historically, all races have continually mixed with their geographic neighbors, never isolating themselves for long.
(2) BRILLIANCE EXISTS IN EVERY RACE. All traits are diverse within each race, such that a single person can not be judged with sufficient certainty based on race alone (only rough probabilistic guesses).
(3) SCIENCE DOES NOT DECIDE MORAL VALUES. No race is further along the evolutionary path than another race. There is no scientifically "higher" or "lower" race, nor is there a scientifically "superior" or "inferior" race, regardless of natural tendencies among races. Inequality of genotypes does not compel inequality under the law. The principle of equal rights has served western society very well, regardless of inequivalencies of mind and body.
(4) THERE IS NOTHING WRONG WITH RACE-MIXING. In fact, genetic diversity is better, reducing recessive genes and enhancing selective advantages (known as "hybrid vigor" in agriculture).
(5) WHITE ARYANS ARE NOT THE MOST INTELLIGENT RACE. Ashkenazi Jews are on average the most intelligence race, followed by Northeast Asians. But, would it really make sense to grant Ashkenazi Jews as anything more than equals in our politics, law and everyday living?
(6) INTELLIGENCE IS NOT UNCHANGEABLE. Even if there are genes that account for intelligence DIFFERENCES, it does not follow that intelligence scores cannot be increased through positive environments, as we know from the Flynn Effect and heritability studies.
(7) WE CAN SOLVE THE GENETIC RACE GAPS. We have the option of finally narrowing the divisive racial IQ gaps through democratically-directed genetic engineering.

A political tactic that most certainly will NOT work: hindering the science concerning race and intelligence. Such a tactic may have success in the western world, but ONLY in the West. The taboos against race differences and eugenics does not exist in the East, in nations such as China, Japan, South Korea, India and Singapore. Eugenics and racial differences have often been openly embraced, for example, by Lee Kuan Yew, the much-loved founding father of Singapore. They have both the means and interest to discover the genes for intelligence. It will happen when a hundred thousand people are surveyed for both their genes and general intelligence scores.

Now, I will explain how I know with high certainty the objective reality that the genes for racial differences in intelligence exist, waiting to be discovered.

BACKGROUND KNOWLEDGE #1: INTELLIGENCE SCORE DIFFERENCES ARE HIGHLY HERITIBLE WITHIN GROUPS. By examining correlations among family members that control for both genes and environment, we know with full certainty that intelligence differences are genetic. For example, there is a 59% match in IQ between fraternal twins reared together (same womb, same household and 50% shared genes), but there is 74% match in IQ between identical twins (100% shared genes) reared in completely different households (Devlin, Daniels and Roeder 1997). This is in addition to many other family pairings we can look at, and the data is unified: shared environment accounts for SMALL increases in IQ correlation, but common genes account for LARGE increases in IQ correlation. There is very little room for doubt, and psychologists are nearly unanimous on this point. Within-group intelligence differences are mostly genetic. It does NOT necessarily follow that between-group intelligence differences must be likewise genetic, as the minority effect of environment can make a big difference (i.e. the same bag of mixed corn seeds scattered in two different fields, one field with soil nutrient-poor and another field with soil nutrient-rich, will grow corn crops with vastly different average health). But, the known within-group genetic effect on intelligence matters because...

BACKGROUND KNOWLEDGE #2: WHENEVER THERE ARE WITHIN-GROUP GENETIC DIFFERENCES, THERE ARE BETWEEN-GROUP GENETIC DIFFERENCES. Think of all the phenotypical ways people WITHIN your own race differ in their genes. This includes both the obvious traits--height, skin color, hair texture, facial geometry, head size, foot size, penis size--and the not so obvious traits--blood type, blood pressure, lung capacity, bone density, lactose tolerance, brain size, and immune resistances. Each of these phenotypic traits are also genotypes that vary BETWEEN races. We know of absolutely no trait that varies within races but not between them. If racial variations in psychological traits happened to be purely phenotypic and not genotypic, it would be like throwing a hundred silver dollars up in the air and they all land on edge. Many activists have taken to defining "race" out of existence by defining "race" as non-overlapping and discrete or by defining "race" with a lower limit of genetic variation, and instead using a different word in place of "race", like "cline" or "haplogroup" or "ethnic group." These arguments are purely rhetorical and irrelevant. Choose any words you like, and the objective implications of the data do not change.

But those two points are only the background knowledge. These are the direct arguments for genes accounting for the racial differences in intelligence:

DIRECT ARGUMENT #1: A SUBSET OF THE SAME RACIAL HIERARCHY OF AVERAGE INTELLIGENCE, EDUCATIONAL ATTAINMENT AND INCOME EXISTS IN EVERY MULTI-RACIAL NATION IN THE WORLD. In his book, "The Global Bell Curve," Richard Lynn collected hundreds of studies of intelligence, educational attainment and income averages among races all over the world, in all the examined significant multi-racial municipalities, including Kenya, South Africa, Australia, Brazil, Britain, Canada, Cuba, Jamaica, Hawaii, Ecuador, Mexico, Netherlands, New Zealand, Malaysia, Singapore, Philippines, and United States. Most of the disputes about the cause of the racial differences in intelligence and SES has been myopic, focusing on the United States alone. But, if EVERY multi-racial nation in the world has the same racial variations, then the argument that explains them all at the same time is by far the most probable. And there is only one such unified argument: genetics is primarily responsible for these racial variations. Peoples may take either all their culture or only bits and pieces of their culture with them as they migrate, but they always take their full genotypes with them. That is why, in evolutionary anthropology and evolutionary psychology, a strong argument for the genetic cause of a phenotype is if that phenotype exists in every (or nearly every) human culture in the world.

DIRECT ARGUMENT #2: THE RACIAL IQ HIERARCHY CORRESPONDS TO THE RACIAL BRAIN SIZE HIERARCHY. Brain size differences are mostly genetically heritable (Pennington et al - A Twin MRI Study of Size Variations in the Human Brain, 2000), brain size differences correlate with IQ differences by 40% (Michael McDaniel - Big-brained people are smarter - A meta-analysis of the relationship between in vivo brain volume and intelligence, 2005), and the same racial hierarchy exists for brain size averages as for IQ averages (Beals, Smith and Dodd - Brain Size, Cranial Morphology, Climate, and Time Machines, 1984, and Rushton - Brain size as an explanation of national differences in IQ, longevity, and other life-history variables, 2009).

DIRECT ARGUMENT #3: IN TRANS-RACIAL ADOPTIONS, THE ADOPTED CHILDREN'S IQ MUCH MORE CLOSELY MATCHES THE IQ OF THE BIOLOGICAL MOTHER THAN THE ADOPTED MOTHER, per Scarr and Weinberg - IQ Test Performance of Black Children Adopted by White Families, 1976.

DIRECT ARGUMENT #4: AVERAGE SKIN COLOR OF NATIVE POPULATIONS STRONGLY CORRELATES NEGATIVELY WITH AVERAGE IQ. Skin color is not race (there is a many-to-many relationship between those two variables), but skin color is a strong indication of the climate of a population's ancestors. Dark skin is a selective advantage in hot climates with excessive UV, and lighter skin is an adaptation to colder climates with low UV (Jablonski and Chaplin - Human skin pigmentation as an adaptation to UV radiation, 2010). Lynn and Rushton theorized that extra intelligence is an adaptation to cold stable climates, where natural resources are scarce (Rushton - Race, Evolution and Behavior, 1995). To test this theory, Templer and Arikawa conducted a study that correlated average skin color of nations with native populations with their average IQ (Templer and Arikawa - Temperature, skin color, per capita income, and IQ - An international perspective, 2006). They found a correlation of -90%. This is an extremely strong negative correlation, greater than the correlations of IQ with either modern average temperature or modern GDP per capita.

So, both biological theory and a diverse array of facts are strongly unified behind the expectation that genetic differences are responsible for the intelligence differences among races. You may ask me, "So why don't professional psychologists agree with you?" My answer is: "Very many of them do." There is only one international organization of research psychologists who specialize in intelligence: the International Society for Intelligence Research (ISIR). In 2006, they awarded Arthur Jensen their first lifetime achievement award. Arthur Jensen was the founding father of the case that the racial differences in intelligence scores are mostly genetic, an accomplishment that towers over his other academic accomplishments in the field. He is a respected grandfather to these academics, regardless of whether they agree or disagree with him (i.e. Sandra Scarr - On Arthur Jensen's Integrity, 1998, and James Flynn - Race, IQ and Jensen, 1980). But, he is slandered as a "White Supremacist" by the Southern Policy Law Center (he wasn't). It is a reflection of the vast abyss between the common academic thinking on the topic and the common public thinking on the topic. The public simply doesn't know how respectable the academic case is for the racial variations in intelligence and its significance. The public would expect that only the KKK would believe it. Most people don't even know that racial variations in intelligence exist, be they either hereditary or environmental. I attached the background image of ISIR's Facebook page, edited to include names on the faces. Most of the faces are people who have made their names by scientifically defending the position of the genetics of the racial IQ gap (Ronald Fisher, Charles Spearman, Cyril Burt, Arthur Jensen, Robert Plomin, Francis Galton, and Charles Murray). Only two of them made names for themselves by defending the environmentalist explanation (Stephen J. Ceci and Sandra Scarr). The other three faces (Alfred Binet, Thomas Bouchard and Charles Darwin) are more-or-less neutral on the debate.

So, whether you agree or disagree with me, it is time to finally let the science on this topic come first, morals next. Only then can we be rational and clear-headed about what the science is and how to respond to it best.

View attachment 2717

There were a sizeable amount of WWII German scientists who believed in such variations but then they were far from clear headed.

 

[ApostateAbe]

The NLSY79 collected military ASVAB scores. They are not quite the same as IQ tests, but they are highly g-loaded, meaning they highly correlate with Spearman's g (and all other intelligence tests, as they all positively correlate with each other). Lay critics may think that nothing counts as a measure of intelligence except IQ tests (which is typically a big concession given the ideological tendency of the lay critics), but intelligence researchers generally don't think that way.

The ASVAB test on items such as auto mechanics and 1970s electronics. These are not measures of intelligence. The ASVAB does not collect information on non-military bound individuals. Just like the other tests (PSAT, ACT) in your data do not collect IQ data. Call me a lay critic, but even I know that teens in the 1980s who took the college entrance exams were planning on going to college, and high scores indicate a readiness and interest in college. And those who did not take these exams where are they?

What it looks like you have is a self-fulfilling prophecy. Since you are throwing around the term, "lay critics" could you please tell us which credentials you have that make you an expert other than a lay interest?

I am a lay advocate. Do not believe anything I am telling you. For anything you doubt, ask for the evidence. Herrnstein and Murray make claims of high correlations with Spearman's g of subtests of the ASVAB, and they cite the evidence, on pages 75-77.

- - - Updated - - -

There were a sizeable amount of WWII German scientists who believed in such variations but then they were far from clear headed.

Yes, but be careful of the habit of dismissing an entire scientific field just because it disagrees with your politics. Decisions of belief concerning science are best made based on facts.

 

[whichphilosophy]

The ASVAB test on items such as auto mechanics and 1970s electronics. These are not measures of intelligence. The ASVAB does not collect information on non-military bound individuals. Just like the other tests (PSAT, ACT) in your data do not collect IQ data. Call me a lay critic, but even I know that teens in the 1980s who took the college entrance exams were planning on going to college, and high scores indicate a readiness and interest in college. And those who did not take these exams where are they?

What it looks like you have is a self-fulfilling prophecy. Since you are throwing around the term, "lay critics" could you please tell us which credentials you have that make you an expert other than a lay interest?

I am a lay advocate. Do not believe anything I am telling you. For anything you doubt, ask for the evidence. Herrnstein and Murray make claims of high correlations with Spearman's g of subtests of the ASVAB, and they cite the evidence, on pages 75-77.

- - - Updated - - -

There were a sizeable amount of WWII German scientists who believed in such variations but then they were far from clear headed.

Yes, but be careful of the habit of dismissing an entire scientific field just because it disagrees with your politics. Decisions of belief concerning science are best made based on facts.

One has to establish the scientific field first. This does come up every so often and while there are some cultural traits there are is no concrete evidence that race alone is the sole criteria.

 

[ApostateAbe]

I am a lay advocate. Do not believe anything I am telling you. For anything you doubt, ask for the evidence. Herrnstein and Murray make claims of high correlations with Spearman's g of subtests of the ASVAB, and they cite the evidence, on pages 75-77.

- - - Updated - - -

There were a sizeable amount of WWII German scientists who believed in such variations but then they were far from clear headed.

Yes, but be careful of the habit of dismissing an entire scientific field just because it disagrees with your politics. Decisions of belief concerning science are best made based on facts.

One has to establish the scientific field first. This does come up every so often and while there are some cultural traits there are is no concrete evidence that race alone is the sole criteria.

By every criterion, psychometrics (including psychometrics of intelligence) is a science: based on a large array of observations, highly predictive, tying into many other established sciences. As intelligence scores are the most consistent metric (except brain size) within psychology, you could make a better case that psychology generally is not a science than intelligence research specifically. But, intelligence research is unique in that there is an extreme gulf in the extent or accuracy of understanding between the public and the academy. As an example, absolutely NOBODY in academia claims that race is the sole determinant of intelligence. Not even remotely.

 

[Togo]

By every criterion, psychometrics (including psychometrics of intelligence) is a science: based on a large array of observations, highly predictive, tying into many other established sciences.

Of course it is. That's precisely why psychologists get trained as to the limitations of psychometrics.

As intelligence scores are the most consistent metric (except brain size) within psychology,

Um.. eh? What do you mean by this. The most consistent metric used in psychology is probably reaction time. I'm not sure what this is supposed to mean.

But, intelligence research is unique in that there is an extreme gulf in the extent or accuracy of understanding between the public and the academy.

You keep on touting the idea that the validity of intelligence testing as a measure of g is universally accepted amongst psychologists. It isn't. Cracking open any undergraduate level textbook on the subject will give you a fair idea why. Some of the reasons are fairly simple, such as the difficulty of removing or controlling for confounding factors. Some are more complicated, such as the tendency in Multivariate Analysis to create correlational relationships that don't relate to actual real-world factors, but are simply the mathematical amalgam of their correlates. The result is the same - IQ testing is accepted as a predictive test. g is more controversial. g as anything other than a purely statistical construct more controversial still. That's why you're looking at a big stack of books, where people can float their own theories and ideas without much evidence, rather than a stack of peer-reviewed studies, where you can't.

And this issue is hardly unique to psychometrics. It's also alive and well in developmental psychology (aka you want to do WHAT to my baby?), in neurophyisology (try explaining why brain lesion experiments on kittens are a good idea), and in clinical psychology (no, schizophrenia isn't contagious, and 'mad' really isn't a clinical term...)

 

[Nice Squirrel]

The ASVAB test on items such as auto mechanics and 1970s electronics. These are not measures of intelligence. The ASVAB does not collect information on non-military bound individuals. Just like the other tests (PSAT, ACT) in your data do not collect IQ data. Call me a lay critic, but even I know that teens in the 1980s who took the college entrance exams were planning on going to college, and high scores indicate a readiness and interest in college. And those who did not take these exams where are they?

What it looks like you have is a self-fulfilling prophecy. Since you are throwing around the term, "lay critics" could you please tell us which credentials you have that make you an expert other than a lay interest?

I am a lay advocate. Do not believe anything I am telling you. For anything you doubt, ask for the evidence. Herrnstein and Murray make claims of high correlations with Spearman's g of subtests of the ASVAB, and they cite the evidence, on pages 75-77.

Once again you send me back to the bible. Do these folks not cite their work? I see a lot of reasons why they chose to ignore certain data sets or argument that the data needs to be fixed by throwing out parts of the data that "skews" it away from their premise. Anyway, the chart was supposed to track IQ across generations and be a predictor. There is no testing of parents in the data provided. I'm not sure where they got their data on parents or if they made broad assumptions such as no high school diploma = less "genetic" intelligence despite many of the parents of this generation not finishing high school (war, jobs,etc.) but it appears the link between parental IQ and wage earning (as opposed to socioeconomic status) is only an assumption pulled out of their arse.