The black-white IQ gap

From about 1917 to 2006, large representative samples of American black adults have scored about one standard deviation below American white adults on the type of verbal and performance IQ tests first created for screening WWI recruits, and later borrowed by David Wechsler to use in his wildly popular scales; considered the gold standard in the field.

Although the black-white test score gap has shrunk somewhat on more scholastic tests where it used to be absurdly high, the longevity and consistency of the gap on the most conventional and respected of official IQ tests has led some to conclude that it is mostly or entirely genetic.

The single most powerful piece of supporting evidence for the genetic hypothesis is the Minnesota Transracial adoption study in which white, black and mixed-race kids were raised from early childhood in white upper-class homes.  Although the adopted white and black kids scored well above the national white and black means (corrected for outdated norms) of about 102 and 86 respectively (U.S. norms)  in childhood (though not at 17), large racial IQ gaps were found among the adopted kids at both ages.


However the study had a problem, as explained by its authors Scarr and Weinberg (1976):

It is essential to note, however, that the groups also differed significantly (p < .05) in their placement histories and natural mother’s education. Children with two black parents were significantly older at adoption, had been in the adoptive home a shorter time, and had experienced a greater number of preadoption placements. The natural parents of the black/black group also averaged a year less of education than those of the black/white group, which suggests an average difference between the groups in intellectual ability. There were also significant differences between the adoptive families of black/black and black/white children in father’s education and mother’s IQ.[1]

Because the children with two black biological parents were adopted later than the children with only one black biological parent, it’s best to exclude them from our analysis and focus only the IQ gap between the adopted kids with two white biological parents and those with one black and one white biological parent.  Not only were both these groups adopted early into white upper-class homes, but since both had white biological mothers, both enjoyed the benefits of a white prenatal environment.  What the study found was that by age seven, the fully white kids average IQ 111.5 and the half-black kids averaged 105.4, a difference of 6.1 points (see chart above).

This difference may sound small, but keep in mind that we are not comparing full-blooded blacks to full-blooded whites, we are comparing half-African Americans to full-blooded whites.  Also keep in mind that because everyone is being raised in the same social class, and social class independently explains such a large percent of the IQ variance at age seven, the entire IQ scale becomes compressed, so instead of the white standard deviation being about 14.5 (U.S. norms), it is only 11.3 in these adopted white kids.  Thus a 6.1 point gap should be thought of as a 0.54 SD gap since 6.1/11.3 = 0.54.

So if kids with one black parent score 0.54 SD below white kids when both are raised in upper class homes and both have white prenatal environments, that 0.54 SD gap is arguably 100% genetic.  And if having one black parent causes a 0.54 SD genetic drop in IQ, then having two black parents should cause a 1.08 SD genetic drop in IQ (note that the national black-white IQ gap in adults has been about 1 SD since WWI).

Failure to replicate

Now before HBDers get too excited, one should remember that the Minnesota transracial adoption study has never been replicated and that three other similar studies failed to find much of any black < white IQ gap, with some even showing the opposite pattern.

Tizard (1974) compared black, white and mixed-race kids raised in English residential nurseries and found that the only significant IQ difference favored the non-white kids. A problem with this study is that the children were extremely young (below age 5) and racial differences in maturation rates favor black kids. A bigger problem with this study is that the parents of the black kids appeared to be immigrants (African or West Indian) and immigrants are often hyper-selected for IQ (see Indian Americans).

A second study by Eyferth (1961) found that the biological illegitimate children of white German women had a mean IQ of 97.2 if the biological father was a white soldier and 96.5 if the biological father was a black soldier (a trivial difference). Both the white and mixed kids were raised by their biological white mothers. One problem with this study is that the biological fathers of both races would have been screened to have similar IQs because at the time, only the highest scoring 97% of whites and highest scoring 70% of blacks passed the Army General Classification Test and were allowed to be U.S. soldiers. In addition, 20% to 25% of the “black fathers” were not African-American or even black Africans, but rather French North Africans (dark caucasoids as we define them here).

A third study by Moore (1986) included a section where he looked at sub-samples of children adopted by white parents. He found that nine adopted kids with two black biological parents averaged 2 IQ points higher than 14 adopted kids with only one biological black parent.  A 2 point IQ gap sounds small, but as I mentioned above, the IQ scale is compressed in kids when everyone is raised in the same social class (which might have been the case in this study), so a 2 point gap becomes 0.18 of the compressed white SD.

The results of this study suggest that half-white kids are 0.18 SD genetically duller than black kids, which predicts that fully white kids are 0.36 SD genetically duller than black kids.  One problem with this study is that the black kids would have had black prenatal environments while many, or all, of the half-white kids would have had white prenatal environments, but given the low birth weight of black babies, if anything this suggests the genetic IQ gap favoring blacks is even larger than 0.36 SD!


We have two quality studies: The Minnesota Transracial adoption study (when black kids are excluded because of confounds) and Moore (1986).  The first study implies U.S. black genes reduce IQ by 1.04 SD in kids (-1.04 SD), while the second implies U.S. black genes increase IQ by 0.36 SD in kids (+0.36 SD).  But the first analysis was based on comparing 55 mixed kids to 16 white kids (total n = 71), while the second analysis was based on comparing nine black kids with 14 mixed kids (total n = 23).  The total n of both studies combined is 94, so the first study provided 76% of the total sample while the second study provided 24%, thus the best I can do is just weigh these two conflicting results by sample size:

Effect of black genes on childhood IQ = 0.76(-1.04 SD) + 0.24(+0.36 SD)

Effect of black genes on childhood IQ = -0.79 SD + 0.09

Effect of black genes on childhood IQ = -0.7 SD

What this suggests is that on a scale where the white genetic IQ is set at 100 with an SD of 15, the U.S. black genetic IQ is 90, at least in childhood (in adulthood it may be around 85 since some IQ genes might not exert influence until post-puberty).  This is consistent with the fact that despite half a century of affirmative action, the average black IQ (when expressed with reference to white norms) remains below 90 in both children and adults (see charts below).

On the other hand, my estimate is based on only two studies with a combined sample of only 71 adopted kids and we can only assume (based on education when known) that the IQs of their biological parents are roughly racially representative.  And although the black-white IQ gap in adults has apparently changed not at all since WWI, the environmental gap might not have changed that much either.  Despite decades of affirmative action, the median wealth for white families in 2013 was around $141,900, compared to Hispanics at about $13,700 and blacks at about $11,000 so even in the age of a black President, environmental factors can’t be ruled out.


Black white IQ gap in the Wechsler Intelligence Scale for Children in the nationally representative samples used to norm each edition:

white iq (u.s. norms) black iq (u.s. norms) white iq (white norms) black iq (white norms) black-white iq gap (u.s. norms) black-white iq gap (white norms)
wisc-r (1972) 102.3 (sd = 14.08) 86.4 (sd = 12.63) 100 (sd = 15) 83 (sd = 13.46) 15.9 17
wisc-iii (1989) 103.5 (sd = 13.86) 88.6 (sd = 12.83) 100 (sd = 15) 84 (sd = 13.89) 14.9 16
wisc-iv (2002) 103.2 (sd = 14.52) 91.7 (sd = 15.73) 100 (sd = 15) 88 (sd = 16.25) 11.5 12
wisc-v (2013) 103.5 (sd = 14.6) 91.9 (sd = 13.3) 100 (sd = 15) 88 (sd = 13.66) 11.6 12

Black white IQ gap in the Wechsler Adult Intelligence Scale in the nationally representative samples used to norm each edition:

white iq (u.s. norms) black iq (u.s. norms) white iq (white norms) black iq (white norms) black-white iq gap (u.s. norms) black-white iqgap (white norms)
wais-r (1978) 101.4 (sd = 14.65) 86.8 (sd = 13.14) 100 (sd = 15) 85 (sd = 13.45) 14.6 15
wais-iii (1995) 102.6 (sd = 14.81) 89.1 (sd = 13.31) 100 (sd = 15) 86 (sd = 13.48) 13.5 14
wais-iv (2006) 103.4 (sd = 14) 87.7 (sd = 14.4) 100 (sd = 15)  83 (sd = 15.43) 15.7  17


Sources for charts:

WISC-R, WISC-III, and WISC-IV U.S. norms, from pg 27 (Table A1) of Black Americans Reduce the Racial IQ Gap: Evidence from Standardization Samples by William T. Dickens & James R. Flynn

WAIS-IV U.S. norms from pg 190 of WAIS-IV, WMS-IV, and ACS: Advanced Clinical Interpretation edited by James A. Holdnack, Lisa Drozdick, Lawrence G. Weiss, Grant L. Iverson

WISC-V U.S. norms from page 157, table 5.3 of WISC-V Assessment and Interpretation: Scientist-Practitioner Perspectives By Lawrence G. Weiss, Donald H. Saklofske, James A. Holdnack, Aurelio Prifitera



Racial differences in penis size


Taken from pg 168 of Race, Evolution and Behavior: A Life History Perspective, Third Edition, by J. Philippe Rushton


Blogger Race Realist continues to be skeptical about racial differences in penis size,  but the data from the United States, where both whites and blacks are reared with similar nutrition, seems to show quite conclusively that blacks (at least those of West African descent) have longer and thicker penises than whites.  From the above chart, assuming a normal distribution, I estimate the average white American man has a penis length of 162 mm (SD = 19) , and the average African American man has a penis length of 170 mm (SD = 19). (since 5% of black men are longer that 200 mm, and 2% of white men are, while 27% of white men have penises shorter than 151 mm, while 15% of black men do).

But small differences is the mean have huge implications at the extremes. Assuming a normal distribution, one in 3.4 million African American men would have a penis length > 264 mm, vs only one in about 30 million white men.

What about penis circumference? Once again, black men come out on top. 9% of African American men are > 150 mm, while only 5% of white American men are. Only 2% of men in either race are < 75 mm. Assuming a normal curve, that implies white American men have a mean penis circumference of 117 mm (SD = 21), while black American men have a mean penis circumference of 121 mm (SD = 23). Note the larger SD in black men; they not only have a higher mean, but more variability. This means that black men will be dramatically over-represented among the thickest penises in America, and among the ten thickest in America, 100% should be black; unless some non-black man has some kind of freak mutation.

Penis Quotient

To put these penis measurements in perspective, one can map them to the IQ scale where the white mean and SD are set at 100 and 15 respectively, but instead of calling them IQs (intelligence quotients), we’d have to call them PQs (penis quotients).  And just as IQ tests like the Wechsler yield a verbal IQ, a Performance IQ, and a full-scale IQ, we can calculate length PQ, circumference PQ, and full-scale PQ.

On such a scale, blacks have a mean length PQ of 106 and a circumference PQ of 103 compared to the white mean which by definition is always 100.  Estimating their full-scale PQ depends on the correlation between length and circumference, which I don’t know, but assuming it’s about 0.45 (like the correlation between height and weight), then their full-scale PQ should average 105.  But it should be noted that U.S. blacks are about 15% white on average, so we might expect full-blooded blacks, raised with First World nutrition, to have a full-scale PQ of 106.

So the black > white PQ difference is only about a third as large as the white > black IQ difference, and similar to the East Asian > white IQ difference.  With the difference being relatively small, it will not be found in all studies, and on a global scale, I’d expect the average white to have a larger penis than the average black, since most blacks live in the Third World where their small genetic advantage is dwarfed by the huge nutritional deficit (which occurs even among Third World elites).

The behavior body connection

I got a few emails asking why someone of my sophistication and social class would even entertain such a tawdry topic.  The answer is I find J.P. Rushton’s research absolutely fascinating in that just as a bigger brain correlates with more adaptive behavior, a bigger penis correlates with more sexual behavior, and that there was an evolutionary tradeoff between these two body parts, as humans marched up the evolutionary tree from monkey to man.  Of course our closest ape relatives don’t have especially large penises but their overall genitalia is huge.  I suspect Homo Erectus had a larger penis than any modern human race.

Bring Mamma home a big one

One of the most infamous moments in the history of The Oprah Winfrey Show was when Oprah was interviewing a nerdy female scientist about penis size and sexual satisfaction.  Not content with boring facts and figures, big brained Oprah sensed her audience wanted to know about the scientist’s sexual preferences.  The scientist didn’t want to get personal and continued to blather on about statistics, at which point Oprah said:

But if you had a choice you’d want a big one, right?  Bring Mamma home a big one!

The audience went wild!

Despite Oprah’s superhuman cranial capacity, from the neck down she is still a typical black woman, and the sex drive of the African jungles still raced through her blood.

It was at this point that Phil Donahue, the former reigning monarch of daytime TV, must have felt his empire crumble.  For he could never compete with the sassy Oprah on a level that truly connected with America.


Though once Oprah became the richest African American of all time, she replaced the trash talk with higher discussions about new age spirituality, literature, and self-actualization.

But millions miss the original Oprah who the public and even the critics couldn’t get enough of.  The one who wasn’t so polished, politically correct, and upper class.  As Howard Rosenberg, TV critic of The Los Angeles Times, observed back on Sept. 8, 1986:

She’s roundhouse, a full-course meal, big, brassy, loud, aggressive, hyper, laughable, lovable, soulful, tender, lowdown, earthy, raw, and hungry.  And she may know the way to Phil Donahue’s jugular.


Down and dirty Oprah from the 1980s, was not the polished classy woman we know today who would never wear fur


The autism-schizophrenia continuum

Commenter Philosopher has been talking a lot about the autism-schizophrenia continuum so I wanted to talk a bit about the basis for this theory and some of the challenges.

The notion that autism and schizophrenia are opposite extremes of the same continuum was perhaps first proposed  by Bernard Crespi, an evolutionary biologist at Simon Fraser University in Vancouver, Canada, and Christopher Badcock, an Emeritus Reader in Sociology at the University of London.  They proposed that just as autism is thought to be an extreme male brain, schizophrenia is an extreme female brain.  The idea is that human neurology forms a bell curve, where normal (neuro-typical people) are in the middle and autistics and schizophrenics are at the extremes.

The role of race

Then in 2014 and 2015, Pumpkin Person argued that the autism schizophrenia continuum was part of Rushton’s r-K evolutionary continuum, where r populations are those that evolved high reproduction rates, low survival rates, and K populations evolved low reproduction rates and high survival rates.  This seemed to explain why schizophrenia was high in blacks and high in the lower social classes, while autism was higher in the upper classes, and perhaps in East Asians.  The notion that blacks are more likely to be schizophrenic may seem incompatible with the idea that schizophrenia is an extreme female brain, since blacks are arguably the most masculine race with perhaps the highest testosterone levels, however physical and temperamental masculinity should not be confused with cognitive masculinity (Steve Sailer made a similar point).

Coolness vs nerdiness

r and K seems to correspond with the stereotypical idea of “coolness” vs “nerdiness” with blacks stereotyped by the U.S. media as the cool race, and East Asians stereotyped as the nerdy race, and whites being the perfect balance between both extremes.

But it’s too simplistic to say that autism is just extreme nerdiness.  For one thing, nerds tend to have high IQs and successful lives (i.e. Bill Gates, Mark Zuckerberg) so if autism were merely extreme nerdiness, you’d expect autistics to have even higher IQs and even more successful lives.  Instead, autistics are often mentally retarded and require lifelong supervision.

Yet we know autism is related to nerdiness because nerds (i.e. people in STEM fields) are more likely to have autistic relatives, though this could partly be because they have children late, thus increasing the mutation load, and not entirely because STEM genes are intrinsically autistic.

However my tentative hypothesis is that as humans migrated out of the tropics and into the colder climates of Northern Europe and especially Northeast Asia, they not only needed higher global IQ, but a different cognitive profile.  While Theory of Mind IQ was crucial in the tropics to gain status and attract mates, in the freezing ice age, women didn’t have the luxury of choosing the guy who most charmed them.  They had to go with the best survivor, so men with primarily technological smarts won out over men with mostly social smarts.

Further, the ice age selected for obsessive focus (an autistic personality) because you had to be in love with only one woman to raise a stable family, and you had to focus on building shelter and clothing before it got too cold.

A Northeast Asian focusing on what matters & not getting distracted

A Northeast Asian focusing on what matters & not getting distracted

By contrast in the tropics, social IQ was more important that technological IQ, because almost all modern humans have enough to technical savvy to survive in warm climates, but only those with the Theory of Mind to manipulate women and undermine their male competitors could reproduce prolifically.  And with so many women to reproduce with, the guy who obsessively focused on just one, lost out genetically to the guy who got distracted by every pretty young thing that walked by (a schizophrenic personality).


tropical peoples love to have fun


Shifting to a two-dimensional spectrum

But while autism and schizophrenia are opposites in where they fall in the male > female, K > r, nerdiness > coolness, ice people > tropical people, continuum, it’s an over-simplification to say they are opposites completely.

On the contrary, schizophrenia and autism are both pathological, both found in many of the same families, and both partly caused by some of the same genetic variants.  So instead of just thinking about a single spectrum, I’ve argued that we need to think in two dimensions, and realize that while autistics and schizophrenia are at opposite extremes on one axis, they are at the same extreme on another.

The dimension on which the two conditions share the same extreme is executive function, a vaguely defined part of intelligence described by Wikipedia as “a set of cognitive processes – including attentional control, inhibitory control, working memory, and cognitive flexibility, as well as reasoning, problem solving, and planning – that are necessary for the cognitive control of behavior: selecting and successfully monitoring behaviors that facilitate the attainment of chosen goals.[1][2][3] ”

Although executive functioning is underrepresented on most IQ tests, it is crucial to how I love to define intelligence: The mental ability to adapt: to take whatever situation you’re in and turn it around to your advantage.

I think combining the executive function spectrum with the nerdiness spectrum better explains autism and schizophrenia than a one dimensional spectrum could. Below is a first draft of the two-dimensional model

low nerdiness normal high nerdiness
high executive functioning Oprah, Bill Clinton, Jesus, the prophet Muhammad typical high achiever Bill Gates, Mark Zuckerberg, Albert Einstein
normal Charles Manson average person typical nerd
low executive functioning schizophrenia typical low achiever autism


Converting the new GRE to IQ

Commenter “purpletigerbot” asked me to investigate the new GRE.  Here are the means and standard deviations (SDs symbolized as σ) of the verbal and quantitative sections of the people who take this test:


The distribution appears to be fairly Gaussian.

In a normal curve, we expect people who are 2 SDs above and below the mean to be in the top and bottom 2% respectively, and that’s more or less true of new GRE takers, on both Verbal and Quantitative sections:


Self-selection among new GRE test takers

In order to convert the GRE scales to IQ equivalents, we need to know how self-selected new GRE takers are.   The average GRE IQ of people who took the old GRE was about 114 with an SD of about 15.  We know this because we can compare their verbal GREs with the verbal GREs of the subset of test takers who also took the verbal old SAT,  and the verbal old SAT can be converted to an IQ scale (and then equated to old verbal GRE scores) since special studies have administered it to the general U.S. teenaged population.

In other words, people who took the old GRE were about as smart as the average college grad of that era.  It’s a bit surprising that such a restricted population would have an SD as large as the general U.S. population SD (15 on the IQ scale) but that’s what the data seems to show and it may reflect the diversity of graduate level majors different students pursue, and it also may reflect the fact that some GRE takers go on to get a PhD, while others don’t even finish their undergrad, and took the test on a lark.

If people who took the old GRE were as smart as the average college grad, those who take the new GRE are probably likewise, but because the average college grad has become dumber (compared to all Americans) since the 20th century, their average IQ would now be about 111, though presumably the SD of the GRE takers is still 15.

Converting verbal, Quantitative, and Composite new GRE scores to IQ equivalents

Converting the new verbal GRE to IQ (U.S.) norms is simply a matter of calculating the verbal new GRE Z score with respect to the new GRE population, and then calculating what IQ that Z score equates to in the new GRE population’s IQ distribution:

Verbal IQ (U.S. norms) = [(New verbal GRE score – 150.22)/8.45](15) + 111

And similarly for the new math GRE:

Math IQ (U.S. norms) = [(New Quantitative GRE scores – 152.47)/8.45](15) + 111

To convert the new GRE V + Q composite into IQ, we must determine the mean and SD of the composite in the GRE population.  The mean can be determined simply by adding the mean V and mean Q, which gives 302.69.  To get the SD of the composite, we must know the correlation between these subscales.  Among the subset of people who took the old GRE after also taking the SAT, the correlation was 0.56.  If we assume the correlation is the same for all GRE takers, and also for new GRE takers, then we can apply the following formula to get the SD of new GRE V + Q composite:


r is the correlation between the two tests that make up the composite and σ is the standard deviation of the two tests.

The above formula gives an SD of 15.35 for the new GRE V + Q composite.  Thus:

Composite IQ (U.S. norms) = [(New GRE VQ composite – 302.69)/15.35](15) + 111


Ceiling and floor of the combined V + Q new GRE

What the last formula tells us is that a perfect V + Q combined score of 340 on the new GRE equates to an IQ of 147 (U.S. norms) or 146 (U.S. white norms).  If all American young adults took the new GRE (instead of just the educated), we’d expect only one in 1,157 to hit the ceiling on both V and Q and only one in 924 white American young adults to do so.

The formula also tells us that someone who obtained the minimum score of 130 on both V and Q, for a combined score of 260, would have a composite IQ of 69 (U.S. norms) or 65 (U.S. white norms).  If one considers college admission tests to be valid IQ tests, and if the person who obtained such a score was an American born English first language speaker who was motivated to do well, such a low score would indicate Educable (mild) Mental Retardation or a learning disability of some kind.

Three types of power in America

Commenter JS wrote:

American proles define status with lifestyle only, the more money = the more hedonism = hence the more status. Ivy League Investment bankers party with state college-frat boys. It’s all about the money. Lion is wrong about Proles vs SWPLs.

And about the Ivy League, its graduates don’t care for learning, they want money, no questions asked!

Americans are class unaware. People marry up or marry down, because they want money.

I’ve never found the concept of social class as traditionally defined, particularly useful for describing America, mostly because social class is all about inherited status, old money and sophistication, and America’s greatest heroes are rags to riches success stories and plain spoken people who can relate to the common man.  And although America has less economic mobility than other developed countries, Americans like to see themselves as the land of opportunity, and actively reject the idea of a caste system or monarchy.

One of the reasons Hillary lost the election is people don’t want the Clintons or anyone else to become a political dynasty because that goes against everything America likes to think it stands for.  One of the reasons Trump won is that despite his wealth, he reflected the populism and vulgarity of the common man.

Also, if you look at America’s most successful demographic (Ashkenazi Jews), they came to the United States with very little wealth, and only achieved their current status within the last several decades.

Thus instead of the idea of social class, I’ve repeatedly argued that what best explains the American hierarchy are three types of power: popularity, intellectual influence, and money.  Whoever has the highest Z score on a composite of all three are the “winners” in America. These three types of capital are not mutually exclusive and one type can be exchanged for another type: Giving billions of dollars to charity, as Bill Gates did, decreases his economic capital (money) but increased his political capital (popularity).  Giving speeches to Wall Street, as Hillary did, cost her political capital, but increased her wealth.

Popularity: The ability to win hearts

This type of power is exemplified by sitting U.S. presidents who are virtually always the most worshipped man in America, other high profile politicians, and First Ladies.  Surprisingly, with the exception of Oprah, and sometimes Ellen and Angelina Jolie, celebrities generally don’t show up that much when Americans are asked (without prompting) to name who they most admire.  Also interesting is the fact that blacks are dramatically overrepresented in this type of power, especially after controlling for IQ.  This might be because blacks are genetically better at more charismatic occupations like politics, entertainment and sports, as part of an evolved strategy for getting numerous mates (J.P. Rushton argued blacks evolved to have higher birth rates at the expense of survival rates), or it could be because they carry a certain moral authority because of slavery, or perhaps blacks are promoted to more visible positions as a form of tokenism.  Likely all three factors play a role.

Interestingly, Jews tend to be quite unexceptional on this type of power after controlling for IQ (Bernie Sanders being a notable exception) either because they lack charisma, anti-Semitism, or because the don’t want to be the public face of power, preferring instead a behind the scenes role.

People who are considered proles also can also do extremely well at this type of power (Sarah Palin and perhaps even Trump, being the most obvious examples).

Intellectual influence: The ability to win minds

This type of power is exemplified by columnists for The New York Times, members of Thinktanks who shape government policy, and professors who write policy books that are read by Senators and Presidents.  Ashkenazi Jews are DRAMATICALLY overrepresented in this type of power, even after controlling for IQ.  Despite being 2% of America they are 50% of the most influential pundits.  By contrast blacks are 13% of America, but only 2% of the most influential pundits.  Proles virtually never achieve this type of power.

Money: the ability to win wallets

This type of power is self-explanatory.  The richest people wield incredible power because they can buy politicians, media outlets, and Think Tanks.  Once again, Ashkenazi Jews are dramatically overrepresented , (36% of the 400 richest Americans despite being 2% of America) and blacks have probably never been more than 0.5% of the Forbes 400, despite being 13% of America.  This might be because prehistorically, economic success was all about having the adaptability to acquire enough resources to survive, but according to Rushton’s theory, blacks evolved a strategy where survival rates were sacrificed to increase birth rates. By contrast nerdy guys like Bill Gates and Mark Zuckergberg, who prehistorically would not have got the most mates, evolved because they were so good at surviving that they were the only ones left to mate with.

Of course IQ alone can’t explain the extreme disparity we see in racial wealth; differences in ethnic networking likely also play a part.  It could be that blacks, being the World’s oldest phenotype and lineage, are the most genetically diverse, and thus have the least in-group favouritism (look at all the black on black crime).  By contrast, Ashkenazi Jews, being an extremely new race, are much more genetically homogenous, allowing more in-group altruism.  See ethnic genetic interests.




More thoughts on the rarity of a 2400 old GRE score

In light of the fact that the most prolific and horrific commenter on this blog (Mugabe, aka chocolate babies)claims to have scored 800 on all three sections of the old GRE, I wanted to explore this test further.  Some people believe him; others are very skeptical.  Some ask why I tolerate him at all.  The reason is I’m a horror fan, and thus have high tolerance for freakish behavior.  The other reason is I LOVE HIS AVATAR!


It’s hilariously ironic to have someone with the avatar of a black man expressing such aggressively alt-right opinions, and even though there’s the stereotype of blacks being less smart, the particular black avatar he chose looks fiercely intelligent, and I’ve finally figured out why.  It’s because it looks like a black Ben Stein, who is rumoured to have a freakishly high IQ.


Enough about Mugabe.  Let’s talk about the GRE.

The GRE and the SSS (the super self-selected)

During the late 20th century, Americans who took the SAT, were self-selected to have an above average IQ (108; U.S. norms),  but those who were academically ambitious and confident enough to take both the SAT, and then several years later, the GRE, appear to have been far more self-selected for IQ than I could have ever imagined.  Indeed based on their verbal SAT distribution (see image below), they had a mean IQ of 120 and an SD of 14, compared to the general U.S. distribution with a mean of 100 and an SD of 15. I will refer to this group as the super self-selected (SSS).


Perfect verbal score on old GRE = IQ 158 (U.S. norms); IQ 157 (U.S. white norms)

Now among the SSS, the GRE verbal (circa 1990) had a mean and SD of 510.1 and 107.7 respectively (see image above), so assuming a normal curve, only one in 261 of these highly self-selected people would score a perfect 800 (a Z score of 2.69 with respect to the SSS).  But because the SSS has a mean IQ of 120 and an SD of 14, a Z score of 2.69 equates to an IQ of 2.69(14) + 120 = 158 (U.S. norms)

Perfect verbal score AND perfect quantitative score on old GRE = IQ 162 (U.S. norms); IQ 161 (U.S. white norms)

Now of those one in 261 SSS who scored 800 on the GRE Verbal (Z = 2.69), how many would score 800 again  on the GRE Quantitative?  Well, given a 0.56 correlation between GRE V and GRE Q in this population, the expected Q score of someone with a Z score of 2.69 on V, would of course be 0.56(2.69) = 1.51 (standard error = 0.83).

Given that the GRE Q has a mean and SD of 573.4 and 125.6 respectively in this  population, a score of 800 has a Z score of 1.8, which is 0.35 standard errors higher than the expected Q score of an 800 V, which means that only one in 2.71 of them should repeat their 800 on the Q section.  Since scoring 800 on V is already a one in 261 performance (in the SSS), getting another 800 on Q becomes a one in 261(2.71) = 707 performance.

Assuming a normal curve, one in 707 is an incredible three standard deviations above average, but because the SSS has a mean IQ of 120 and an SD of 14, it equates to an IQ of 3(14) + 120 = 162 (U.S. norms)

Perfect score on ALL THREE SECTIONS of the old GRE = IQ 164 (U.S. norms); IQ 165 (U.S. white norms)

Now of the one in 707 SSS who scored 800 on both GRE V and GRE Q, how many did it yet again on the analytical section?  Given that the correlation, in the SSS, between GRE V and GRE A is 0.65, and the correlation between GRE Q and GRE A is 0.73, and the correlation between GRE V and GRE Q is 0.56, the following multiple regression equation can be derived:

Expected Z on GRE A = 0.53(Z on GRE Q) + 0.35(Z on GRE V)

Applying this formula to someone with a perfect V (Z = 2.69) and a perfect Q (Z = 1.8), gives:

Expected Z on GRE A = 0.53(1.8) + 0.35(2.69)

Expected Z on GRE A = 0.954 + 0.942

Expected Z on GRE A = 1.9 (standard error = 0.62)

Now in the SSS, the GRE A has a mean of 579.7 and an SD of 117.6, so a score of 800 has a Z score of 1.87, which is 0.05 Standard errors below the expected score of someone who scored 800 on V and Q.  What this means is that of the one in 707 SSS who scored perfect on BOTH V and Q, one in 1.9 would also score perfect on A.

Thus, those who achieve the perfect trifecta have a rarity of one in 707(1.9) = 1,343, within an already highly filtered group.  In a normal curve, one in 1,343 is 3.17 standard deviations above the mean, but because the SSS has a mean IQ of 120 and SD of 14, it equates to:

IQ = 3.17(14) + 120

IQ = 44 + 120

IQ = 164 (U.S. norms)

In theory, if all American young adults in the late 20th century had taken the GRE, only about one in 100,000 should have scored perfect on all three sections, and only about one in 136,000 white American young adults should have done so.

Converting the old GRE to IQ

Commenter Mugabe (aka chocolate babies?) has claimed to have scored a perfect 800 on all three sections of the old GRE.  Some commenters, such as “Deal with it!” believe him, others are deeply skeptical.

In one study, the quantitative GRE correlated 0.71 with WAIS-R full-scale IQ, though the sample was small and restricted.


So the question becomes, if the GRE is considered equivalent to an IQ test, what IQ did a perfect 2400 GRE equate to?

For decades people have been given GRE subscale scores (verbal, math, analytical) and the percentiles that go with them, but had no idea how to interpret their COMBINED GRE scores.  In order to interpret any standardized test score, the first thing you want to know is the Z score, and in order to know the Z score, you must know the mean and the Standard Deviation (SD).  According to one source, the means and SDs (in parentheses)  for 1.1 million people taking the GRE from 1994 to 1997 were 474 (114) for the verbal, 558 (139) for the Quantitative, and 547 (130) for the analytical.

However knowing your Z score tells you little, if you don’t know anything about the population from which your Z score was derived.  A low Z score from brilliant population could be more impressive than a high Z score from a low IQ population.  Thus instead of using the data on 1.1 million GRE takers of unknown intelligence, I am going to use GRE data from a smaller sample of GRE takers with known SAT scores:


The above table was poorly formatted, but what it shows is that in a sample of people who took both the GRE and the SAT (circa 1990), the mean GRE verbal was 510.1 (SD = 107.7), GRE Quantitative was 573.4 (SD = 125.6) and the GRE analytical was 579.7 (SD = 117.6).  Moreover, in this sample, the correlation between V & Q scores was 0.56, V & A scores 0.65, and Q & A scores 0.73.

Armed with these means, SDs, and correlations, we can estimate the mean and SD of the COMBINED GRE score (V + Q + A)

According to commenter Mugabe:

var(X+Y+Z) = var(X) + var(Y) + var(Z)+2*(sigma(X)sigma(Y)rho(X,Y) + sigma(X)sigma(Z)rho(X,Z) + sigma(Y)sigma(Z)rho(Y,Z))

Mugabe advises us not to use this formula because the math subscale has a low ceiling, but let’s be rebellious and use it anyway, substituting V, Q, and A for generic X, Y, and Z(note variance equals squared standard deviation):

var(V+Q+A) = var(V) + var(Q) + var(A)+2*(sigma(V)sigma(Q)rho(V,Q) + sigma(V)sigma(A)rho(V,A) + sigma(Q)sigma(A)rho(Q,A))

var(V+Q+A) = 11,599.29 + 15,775.36 + 13,829.76 + 2*(107.7)(125.6)(0.56) + (107.7)(117.6)(0.65) + (125.6)(117.6)(0.73)

var(V+Q+A) = 41,204.41 + 15,150.37 + 8,232.59 + 10,782.51

var(V+Q+A) = 75,369.88

Taking the square root of the variance, tells us that the SD of the combined composite (in our sample) should be 274.53, and of course the mean of the composite is simply a matter summing the sample’s mean on each of the three sub-scales (1,663.2).

Thus Mugabe claims to have scored 2.68 SD above our sample GRE takers.

But in order to assign that an IQ, we need to know how talented the sample was.  Their pre-1995 verbal SATs have a mean of 518 and an SD of 104.7 (which on the IQ scale equates to a mean of 120 (SD 14.14)(U.S. norms)).  If we assume they were as self-selected for combined GRE talent as they were SAT verbal talent, then being 2.68 SD above them on the combined GRE equates to an IQ of:

2.68(14.14) + 120 = 158 (U.S. norms) or 157 (U.S. white norms)

However because of ceiling bumping, this is a very conservative estimate, but the g loading of the GRE, especially at high levels, has not been well researched, and some researchers question the validity of g as a measure of intelligence (but that’s a whole other post).



The alt-right celebrates Trump victory

In light of white nationalist Richard Spencer holding a meeting in Washington on Saturday to celebrate Trump’s victory, the media has been talking a lot about the alt-right.  I could not believe that mainstream media like CNN were giving them so much attention, but perhaps they see it as a way of undermining Trump through guilt by association.

I was sad that such a major white nationalist meeting could have occurred in Washington in 2016, but as a serious amateur journalist, I knew it was my responsibility to cover it, so I listened to the event on youtube as I lay down on the pillow to sleep.

I had previously written a blog post fearing Richard Spencer could one day run for President, and perhaps with the election of Trump, he now feels emboldened to play a larger role in public life. Spencer is very  articulate and polished in interviews, but aside from a few terrifying applause lines (referring to the mainstream media as the Lügenpresse and yelling “hail Trump” ) his speech dragged on a bit.

The big star of this disturbing event was Kevin MacDonald who some describe as the intellectual Godfather of the alt-right.


In a very provocative speech, MacDonald expressed hope that Trump could be a hero to his white people, but fears that Trump’s administration is being hijacked by Zionists that will pursue Israel’s interests at the expense of America’s and worried that pro-Israel elites have brainwashed too many Christians into becoming Christian Zionists.

It’s a bit of misnomer to call these people the “alt-right”.  They’re certainly far right on cultural issues , but on foreign policy they’re just incredibly anti-neocon.  Spencer for example is a huge critic of the Iraq war, opposes support for Israel, and even supports the Iran nuclear deal, though all of this takes a back-seat to being anti-immigration, which is their number one issue.

And although some of the rhetoric at the event sounded disturbingly anti-Semitic to me, I felt so much better when I learned that some Jews were there, such as twitter star “the reactionary Jew”.  Although the alt-right has criticised Jews for pushing immigration on Western countries while supporting extreme nationalism in Israel, the reactionary Jew feels that all peoples have the right to be as nationalist as Israel is.

The real takeaway from all this is that Trump is the first internet President.  For all the talk that Obama used social media to get elected, his 2008 victory was really the result of support from traditional media (Oprah in the Democratic primary, the cable pundits and print media in the general election).

By contrast, Trump was incredibly opposed by the traditional media in the general election, but the power of his internet support completely overwhelmed them.

We are living in scary times.

Such scary times that Peter Beinart has a provocative article in The Atlantic arguing that Trump’s presidency is so dangerous, the electors should use their constitutional power to overturn it.



Simple formula for converting 1970 to 1994 SAT into IQ equivalents

[NOTE: Pumpkin Person does not endorse the SAT (old or new), as a great measure of IQ, BUT, if one wants to express their old SATs on the IQ scale, here are simple ways of doing so]

I have previously cited a rare study showing that if all American young adults (in the early 1970s) had taken the old SAT (pre-1995), not just the college bound elite, the mean verbal score would have been 368 with an SD of 111, and the mean math score would have been 402 (SD = 112).


Thus converting old SAT verbal and math scores into IQ equivalents (U.S. norms) was simply a matter of converting them to Z scores, then multiplying by 15 and adding 100.


formula 1:

verbal IQ (U.S. norms) = [(verbal SAT – 368)/111][15] + 100

formula 2:

math IQ (U.S. norms) = [(math SAT – 402)/112][15] + 100

Now what happens if you want to convert the composite old SAT score (verbal + math) to IQ.  Well we know the mean score if all Americans had taken the test would have been about 770 (the mean verbal + the mean math), but we don’t know the standard deviation.

On page 779 of the book The Bell Curve by Herrnstein and Murray, they cite the formula for calculating the standard deviation of a composite score.


r is the correlation between the two tests that make up the composite and σ is the standard deviation of the two tests.

Herrnstein and Murray also claim that for the entire SAT population, the correlation between SAT verbal and SAT math is 0.67.  Of course we’re interested in the correlation if ALL American young adults had taken the old SAT, not just the SAT population.  If they had, it’s possible the correlation would have been higher than 0.67 given less range restriction in the general population compared to the college bound population.  On the other hand, the college bound population had studied verbal and math skills more diligently during high school, thus perhaps inflating the correlation.  Assuming these two factors cancel out, and the correlation was probably the same for the college bound population as for the general population, then applying the above formula gives a general population combined standard deviation of 203.77.


formula 3:

full-scale IQ (U.S. norms) = [(combined SAT) – 770)/203.77][15] + 100

This formula appears to give fairly good results, at least up to the mid 1550s.  For example, scholar Ron Hoeflin claimed that out of a bit over 5,000,000 high-school seniors who took the SAT from 1984 through 1988, only 1,282 had combined scores of 1540+.

Hoeflin has argued that even though only a third of U.S. teens took the SAT,  virtually 100% of teens capable of scoring extremely high on the SAT, did so, and whatever shortfall there might be was negated by bright foreign test-takers.

  Thus, a score of 1540+ is not merely the 1,282 best among 5 million SAT takers, but among ALL fifteen million Americans who were 17 years-old anytime from 1984 through 1988.  In other words, 1540 was a one in 11,700 score, which on the normal curve, equates to an IQ of 157 (sigma 15).

Using formula 3, 1540 also equates to exactly IQ 157.

However above 1560, the formula seems to yield IQs that are too low, given their actual rarity.  This is because people who scored above 1560 typically hit the ceiling on the math section and approach the ceiling on the verbal, so people capable of scoring well above 1600 if the test had more hard items, tend to cluster in the high 1500s.






Chris Matthews is the best host on cable news

I love Chris Matthews.  He’s  very smart, quick on his feet, aggressive, non-ideological, and passionate about U.S. politics.  He’s also a fantastic interviewer. Unlike other hosts on both the left and the right, who are just trying to push an agenda, Matthews has a genuine love for the ART of politics.  He covers politics the way an obsessive sports fan would cover baseball.  He just loves the game, and keeping score, and it’s a beautiful thing to see.


And to his credit, he was one of the few U.S. talking heads with the judgement and integrity to oppose the Iraq war before it began, and he opposed it right from the VERY moment it became a serious idea, yet unlike most white liberals, he’s not preachy and self-righteous.  He comes from a family of Republicans so he’s open-minded enough to see both sides.

The U.S. media is so completely controlled, and the range of acceptable debate is so narrow, that there are so few cable news shows worth watching at all, but within the narrow confines of that controlled debate, Matthews does an excellent job educating his audience and making politics fun.  If MSNBC were smart they’d give him a better time slot.