Generally speaking, it’s a bad idea to use culturally loaded tests like the SAT to compare the intelligence of people from very different cultures (i.e. 21st century America vs. 21st century Japan, 21st century America vs. 19th century America) however in light of fascinating new claims that (genetic) intelligence has declined by a full standard deviation (1 SD) in just the last century or so, even as scores on culture reduced IQ tests have increased by over 2 SD over the same time, I decided to look at some old SAT data with new eyes.
On page 429 of the book The Bell Curve by C. Murray and R. Herrnstein, they have a chart showing the percentage of American 17-year-olds capable of scoring 700+ on the old verbal SAT and old math SAT. Even though only about a third of U.S. young adults took the old SAT (on a good year), the authors assumed that the higher the ability, the greater the odds of taking the test, so they assumed that virtually every 17-year-old American capable of scoring 700+ actually took the test, allowing them to express their data as a percentage of an entire generation, not just the college-bound segment.
The data showed that over a 26 year span (1967-1993), the percentage of American 17 year-olds capable of scoring 700+ on the old verbal SAT dropped from 0.8% to 0.3%. This implies a 0.33 SD decline in just 26 years, equivalent to a decline of 1.92 verbal IQ points a decade! Recklessly extrapolating, that’s a drop of 19 verbal IQ points in a century!
However math SAT scores showed a different pattern. The percentage of 17-year-olds capable of scoring 700+ on the math SAT increased from roughly 1.25% to roughly 1.6%, implying the math distribution moved 0.27 SD to the right over those same 26 years. This implies a gain of 1.54 math IQ points a decade (or 15 points a century).
While it’s unwise to draw longterm conclusions from a test as cultural as the SAT, in my very humble opinion, the data makes perfect sense. Innovative chronometric research by scholars Michael A. Woodley, Guy Madison and Bruce G. Charlton, implies that because of dysgenic trends (including declining infant mortality), general intelligence has declined by 1.8 IQ points a decade (at least in women). Very similar to the verbal SAT (the more g loaded SAT subscale) drop of 1.92 IQ points a decade.
However at the same time, scholar Richard Lynn showed that better nutrition has been improving brain size and perhaps neurological development, causing scores on spatial tests to increase by over 2 SD over the 20th century. However nutrition only seems to consistently improve spatial ability. There’s been virtually zero Flynn Effect on tests of working memory (Digit Span, Arithmetic). Since the math SAT requires both spatial reasoning (high nutrition loading) and working memory (zero nutrition loading), it shows a Flynn Effect intermediate between these two abilities.
Of course one shouldn’t take my analysis too seriously because I only looked at data from 1967-1993, and I only looked at very high SAT scores which do not correlate well with trends in the general population (in the general population verbal IQ has gone up substantially!). However the gifted might be the best place to look for longterm intelligence trends because the most brilliant people tend to teach themselves, so their scores are more indicative of true ability, while the psychometric scores of more average people are more sensitive to externally imposed cultural opportunities (schooling, educated parents, mass media exposure, etc) and thus can be spuriously inflated by cultural bias. The pioneer of mental testing, Sir Francis Galton, commonly judged the intelligence of entire populations by the number of highly gifted people they produced.
Future research on dysgenics should continue to focus on the verbal skills of elites, perhaps analyzing the idea density of the speeches of U.S. presidents, from the 18th century to the 21st century.
A person on twitter recently implied that the extremely high IQ I estimated for Oprah was inconsistent with some of the irrational ideas she seems to believe. Of course rationality is subjective. I for example feel it’s irrational to believe in God, however I’ve watched in amazement as arguably the World’s biggest brained and highest IQ theist Chris Langan made fools out of atheists for denying God’s existence. For how can one “know” there is no God?
“The same way you can know anything else”, said America’s highest IQ woman Marilyn Vos Savant when a reader asked her that very question. “By judging the substance of the evidence and drawing a conclusion. If we insisted on first hand verification, we would know very little…”
And the smartest person I ever corresponded with was a hardcore atheist because he could not respect any mind that would suspend all reason when it comes to the most important questions in life.
When Phil Donahue told legendary atheist Ayn Rand that she wasn’t smart enough to know there was no God, she replied “Yes I am. And so is everyone in this room. That doesn’t take much intelligence.”
Many studies show that religiosity is negatively correlated with IQ, so I would imagine that atheists are more intelligent than agnostics who are more intelligent than the spiritual who are more intelligent than the religious. These would be average differences of course, and some hardcore religious fundamentalists are much more intelligent than even most strident atheists.
Oprah was raised hardcore religious in the rural South, but gradually drifted away from the dogma and began defining God in such liberal and meaningless ways that she provoked the ire of both religious and atheist extremists. Despite distancing herself from the church, she has occasionally been accused of promoting ideas that mainstream scientists would consider pseudoscience and/or magical thinking. The biggest example of this is The Secret which argues that wishing/believing/imagining you can achieve something will cause that belief to come true. When Oprah saw that book becoming popular, she enthusiastically jumped on the bandwagon, arguing that she had independently discovered this law of the universe decades earlier and was excited that someone had written such a popular book about it. However Oprah cautioned that the The Secret was only one law operating in the universe and that it’s not the explanation for all success or failure.
Now in fairness, there’s no doubt that positive thinking is useful. For example, on pg 576 of The g Factor, Arthur Jensen notes that an important personality trait in successful life outcomes is locus of control (the belief that you have the power to shape your destiny). And noting that applying to Harvard is a better predictor of future income than attending Harvard, Steve Sailer writes“I suspect that how much money somebody makes correlates to a surprising extent with how much money they expect to make and/or think they deserve to make.” It’s only when The Secret implies that thoughts in and of themselves create reality (without intermediaries like behavior) that it becomes irrational.
Another seemingly irrational belief-system Oprah has strongly endorsed is the perspective of Gary Zukav (author of The Seat of the Soul) which argues that humans are evolving from five-sensory beings that seek physical power (i.e. wealth, military strength) to multi-sensory beings that seek authentic power (inner peace) and that the universe is wise and compassionate and constantly trying to align us with our soul’s purpose.
Oprah argues it’s important to listen to the signs the universe is giving us so that we can flow with the current of the universe rather than trying to swim upstream.
So how can I claim Oprah is brilliant when she promotes such “pseudo-scientific magical thinking”? I believe there are 3 major explanations:
1) Although I argue that Oprah’s overall IQ is 140, I believe she has a very lop-sided intelligence, with her verbal IQ and social IQ being much higher than her mathematical IQ and technological IQ (as she herself would probably agree). Indeed I estimated that her math IQ is “only” 113, which while high compared to most Americans, would be low for a self-made billionaire.
If you are mediocre at math, you are mediocre at logic and rationality and thus critical thinking. You are also more likely to suffer from what’s called bounded cognition, because if you don’t understand probability theory, it’s easy to believe that the freak coincidences that we observe in life are signs from the universe. This would be especially true for someone like Oprah who must have had incredible good luck to have gone from poverty to the most successful woman in the world in only a few decades. In order for that to happen, a lot of random events must have lined up perfectly, putting her in exactly the right place at the right time to use her considerable gifts. It’s very easy to view such unusual randomness as evidence as some kind of magical process if you don’t have the statistical understanding to realize that extreme coincidences happen all the time.
One extreme coincidence that helped launch Oprah’s career was the fact that when she was still just a local star in Chicago (not yet nationally famous) she was incredibly obsessed with Alice Walker’s book The Color Purple, and didn’t realize that one of the producers for the film adaptation just happened to be in her city, see her on local TV (knowing nothing about her) and instantly think she would be perfect to play a character in the film named Sophia, who just happened to be married to a character named Harpo (Oprah spelled backwards)! It would take incredible rationality to not revert to magical thinking when you experience that level of serendipity.
2) Just as relatively low math IQ can cause magical thinking, I believe a high social IQ can also cause magical thinking. For example, a low social IQ is one of the defining traits in autism, and on some dimensions, autism appears to be the opposite of schizophrenia. Schizophrenia is characterized by extreme magical thinking to the point of being delusional. I’m not in any way suggesting Oprah is schizophrenic (on the contrary, her mental health is excellent); but I am suggesting that there’s a neuro-evolutionary continuum (probably on the r-K dimension), where at the K end of the spectrum you are more prone to low social IQ (relative to overall IQ), autism, and hyper-rational pro-science views, and at the r end of the spectrum, you’re more prone to high social IQ (relative to overall IQ), but lower math IQ and more magical thinking.
It’s been noted that the central deficit in autism is hypo-mentalizing (the failure to adequately consider that other people have minds with feelings and intentions just like you). By contrast, incredibly socially intelligent people like Oprah are so good at mentalizing that they likely even ascribe mental states in mindless entities like the universe. So when random events helped make Oprah rich and famous, she was likely to believe the universe was intentionally trying to help her. An incredibly high social IQ combined with a mediocre math IQ is likely very common in spiritual thought leaders like Oprah and probably would have been found among the prophets of the World’s great religions.
Social IQ > Math IQ is a dangerous combinations because it makes one especially prone to irrational beliefs while at the same time makes them especially skilled at getting others to follow these beliefs. By contrast, scientists tend to have the opposite profile, so despite being correct, often lack the social IQ to persuade the public.
3) A final, and more sinister reason why someone as brilliant as Oprah might promote irrational ideas is that she doesn’t actually believe them but just cleverly used them to attract a larger and more obedient audience by pretending to have some magical solution to most of life’s problems. By claiming for example that she has lived her life according to the laws of The Secret, she quickly became the poster-girl for that wildly successful movement, since her astonishing success was the greatest proof that The Secret works. This caused Oprah’s show to be must-watch TV for all the fans of The Secret and allowed Oprah to claim credit for The Secret‘s success, further enhancing her image as a cultural trendsetter. While this may sound incredibly cynical, a former producer of Oprah’s named Elizabeth Coady claimed that Oprah is a calculating master-manipulator who doesn’t actually believe what she says. Of course Coady is a disgruntled ex-employee who was likely bitter that a confidentiality agreement prevented her from profiting off a tell-all book a book about Oprah, so she may not be the most objective witness.
Although I came of age at the peak of Oprah’s cultural influence, I was not particularly interested in her until the day I overheard her talking on TV about the fact that her hats have to be custom made because her head is so large. It quickly occurred to me that at some time in her her life, Oprah may have been not only the most powerful and prosperous woman in the world, but also, the biggest brained woman in the world. Historically, Social Darwinism was used to diminish women, minorities, and the poor, so to see a black woman from such humble origins be so impressive on perhaps the two most Darwinian correlates of intelligence (money/power and brain size) was incredibly inspirational.
In 2010, Time.com asked Oprah and 11 other of America’s top female business leaders (as selected by Fortune magazine) to answer five questions. The questions were:
1) What is the best and worst decision you’ve ever made?
2) What was your dream job as a kid and why?
3) What do you think is the most significant barrier to female leadership?
4) What woman inspires you and why?
5) What will be the biggest challenge for the generation of women behind you?
I emailed the author of the Time piece telling him how scientifically valuable it was to see so many successful women all agreeing to answer the same set of questions. I did not tell him the purpose of my research but he informed me that he had published the exact unedited words of the women themselves. Most of the women (including Oprah) had emailed their answers to him directly, though a few responded by phone.
Because Oprah had answered the same questions, in mostly the same way (email, complete sentences, a few paragraphs per question), for the same publication, for the same purpose, as 11 other women with similar occupational status, this was a rare opportunity to measure Oprah’s cognitive ability on a highly standardized task against a very comparable control group. But how does one measure intelligence from a sample of writing? A Promethean once, somewhat facetiously, estimated my IQ by doing a Flesch-Kincaid readability calculation on an article I had published. I’ve explored this methodology and while it seems to give somewhat valid results in children, in adults it seems to reward a long-winded ostentatious writing style, which doesn’t make for efficient communication. Clearly a better method was needed…
The Nun Study
While searching for ways to estimate intelligence from writing, I came across the most fascinating study I have ever read. In the Nun Study, Dr. David Snowdon, a leading expert on Alzheimer’s disease, convinced a group of elderly nuns to take cognitive tests and allow their brains to be examined postmortem. This allowed Snowdon and his colleagues to identify dementia and Alzheimer’s disease in the older nuns, but Snowdon wondered if dementia in the elderly could be predicted from cognitive ability in young adulthood. Unfortunately, there were no available mental test scores from when the nuns were young.
Then Snowdon and his team discovered a goldmine. A stack of handwritten one page autobiographies that the nuns had written roughly six decades earlier when they first joined the convent as young women. Because the nuns had written autobiographies of similar length, for the same purpose, following identical instructions about what topics to include, these writing samples were highly comparable and provided an excellent window into the nuns’ early life cognitive ability. But Snowdon asked the same question I would ask years later. How do you measure cognitive ability from a language sample? Snowdon tried various methods like looking at the level of vocabulary each autobiography contained, but craved a more effective technique.
Idea Density
According to his book about the Nun Study (Aging with Grace), Snowdon decided to contact a language expert to help him analyze the biographies. He phoned the brilliant psycholinguist Dr. Susan Kemper who suggested that the most powerful way to measure mental ability from language samples is to quantify both idea density and, separately, grammatical complexity. Grammatical complexity is related to working memory and ranges from simple one-clause sentences to complex sentences with multiple forms of embedding and subordination. By contrast, idea density measures how succinctly you express yourself.
Intelligence can be defined as the cognitive ability to adapt (i.e. problem solve, turn situations to your advantage). If an advantage is a benefit, and a disadvantage is a cost, one could define intelligence as the mental capacity for low cost/benefit behavior, which is why making a lot of money for doing very little work is considered smart, all else being equal. In a trivial sense, every word we say or write has a cost (in the time it takes to write it, and the time it takes others to read it), but every idea we express is a benefit because we’ve communicated something of substance. So generally speaking, the more ideas we can express with as few words as possible, the lower the cost/benefit ratio of our behavior and the more intelligently we’ve behaved.
Amazingly, the idea density from just the last 10 sentences of the nun’s autobiographies correlated a potent 0.6 with their scores on the Mini-Mental State Examination (a brief measure of global cognitive ability) administered roughly six decades later. This is higher than the correlation of two different actual IQ tests administered in youth and old age, for example an outstanding study by scholar Ian Deary and his colleagues, published in the prestigious journal Intelligencefound that the Moray House Test scores at age 11 correlated 0.48 with Raven scores at age 77, though the correlation was higher in women (0.55). Thus, the 0.6 correlation roughly six decades later with the Mini-Mental State Examination would seem to validate idea density as a measure of intelligence; indeed idea density is said to reflect overall neurocognitive development, rather than just a specific talent like verbal ability.
Snowdon and his colleagues were not surprised that idea density (and to a lesser extent grammatical complexity) predicted cognitive functioning in later life. The theory of cognitive reserve predicts that people with extra capacity (i.e. large brains, well developed minds) are able to delay the cognitive symptoms of Alzheimer’s longer because when their brains are afflicted by disease, they have enough extra brain mass and enough extra brain power to compensate for the damage. However the surprising finding of the Nun Study was that idea density also strongly predicted getting Alzheimer’s in the first place. Snowdon claimed in his book that simply by measuring the idea density in the last ten sentences of autobiographies written in the early 20s, they were able to predict with 80% accuracy which nuns would have the Alzheimer’s level of brain tangles at autopsy six decades later. This suggests that by age 20, many people already have very incipient Alzheimer’s that shows up linguistically in extremely subtle ways, but doesn’t progress into dementia until six decades later.
The results of the Nun Study were so astonishing that it made the cover of Time magazine and Snowdon was interviewed by Oprah’s old talk show rival, Phil Donahue.
The Nun Study makes the cover of Time magazine
Measuring the idea density of Oprah and other female elite business leaders
There was something symbolic about using a study of nuns (spiritual women) as a model to estimate Oprah’s intelligence since Oprah was preaching at her church at the age of three and decades later, would emerge as perhaps the most influential spiritual leader, ushering in a culture of secular new-age thinking. And just as the highly educated nuns studied by Snowdon and Kemper were exceptionally accomplished women for the standards for women in their generation, Oprah and the 11 female business elites I compare her idea density to, are exceptionally accomplished for the standards for women today.
I measured the idea density of Oprah and the 11 other elite female business leaders by pasting all the answers they gave to Time.com’s questions into a computer program called CPIDR 3.2.2785.24603. To illustrate how CPIDR works, consider the following two sentences:
1) I live in a house that is big.
2) I live in a big house.
Both sentences say the same thing, but because sentence 2, says it with fewer words, it has a higher idea density (also known as proposition density). CPIDR scores sentence 1 at 0.375 while sentence 2 gets a score of 0.5. Before scoring language samples on CPIDR, Dr. Susan Kemper advises that all multi-word names of people, places or dates be replaced by placeholders because long names add more words without adding more information and thus spuriously lower the ratio of propositions to words. Thus, the sentence “My name is John Smith and I was born in Dallas, Texas on October 31, 1877” should be entered into CPIDR as “My name is NAME and I was born in PLACE on DATE.”
Once such changes were made, Oprah’s answers to Time.com’s questions clocked in at 0.542. By comparison, the answers of the other 11 elite business leaders (the reference group) averaged 0.532 (Standard Deviation (SD) = 0.031)(Range = 0.489 to 0.610). Thus Oprah scored 0.32 SD above the reference group. It should be noted that these idea densitities are generally lower than those reported for nuns in the nun study, and that’s because CPIDR gives an indirect measure of idea density which produces lower scores than the directly measured idea density of the nun study. But the two methods are extremely high correlated, despite this systematic difference.
It should be noted however that Oprah was born in 1954 and the average birth year of the other 11 women was about 1960. Because Kemper’s research shows that idea density declines (within the same person) precipitously with age in a very linear way, beginning perhaps in the 20s, age adjustments are essential. Kemper found that a group of older adults (mean age 76.4) had a mean proposition density that was 1.56 SD lower than younger adults (mean age 22.8). This implies that idea density declines at a rate of 0.029 SD a year. Since Oprah is six years older than the average woman in the reference group, I added 6(0.029 SD) to her score, which increased it to 0.494 SD above the reference group.
Converting idea density to IQ
If one assumes that idea density correlates about as well with IQ as two different IQ tests correlate with one another, then one can convert idea density into IQ equivalent scores using a psychometric technique known as equipercentile equating or score pairing (see section 8.4.1 of this Prometheus document). Score pairing assumes that if a group of people get scores on two quite g loaded mental tests, x and y, then the distribution of x will mirror the distribution of y. That is to say if 50% of a sample is above the 98 percentile on X, then 50% of the sample should be above the 98 percentile on Y. That doesn’t mean the same individuals in the sample will be above the 98 percentile of both X and Y, it just means that being above the sample mean on X is as statistically rare as being above the sample mean on Y, and X and Y are equivalent and interchangeable measures of intelligence.
Thus, in order to convert Oprah’s idea density into an IQ equivalent, one must know the IQ distribution of the reference group she’s being compared to. The reference group were all women Fortune magazine ranks among the 50 most powerful in business. In a previous post, I noted that the average IQ of all Fortune 500 CEOs is likely about 124, but the tiny subset of women who crash through the glass ceiling to reach the top of American business likely average a brilliant IQ of 131. Assuming they have a similar IQ variability as the general population (SD 15), and assuming idea density and IQ scores are statistically interchangeable, then Oprah being 0.494 SD more idea dense than this outstanding group implies an extremely high IQ of 0.494(15) + 131 = 138. An IQ of roughly 140 is consistent with a previous analysis where I used multiple regression to predict Oprah’s IQ from Darwinian correlates of intelligence (income and brain size). It is also consistent with my historiometric estimate of Oprah’s childhood IQ. When disparate methodologies converge on one conclusion, probable truth is implied.
In the following video, Oprah displays high idea density by asking a complex question succinctly:
It may seem surprising that a mere daytime talk show host from the backwoods of Mississippi is more intelligent than most elite female business leaders, many of whom have attended the best colleges in America and are CEOs of some of the biggest high tech companies. But one must remember that Oprah’s brain size, wealth and impact on the culture is immensely greater than that of the other elite female business leaders, implying greater ability, especially since she overcame poverty and adversity to dominate the ultra competitive, improvisational and creative field of TV talk shows. High intelligence was likely a factor in Oprah immediately overtaking the very bright former talk show king Phil Donahue in the television ratings. Back in the 1980s, Newsday‘s Les Payne observed:
Oprah Winfrey is sharper than Donahue, wittier, more genuine, and far better attuned to her audience, if not the world.
And British actress and Cambridge graduate Thandie Newton believes incredible intelligence made a Oprah a good film actress too, stating:
I’ve worked with lots of good actors, and I know Oprah hasn’t made many films. I was stunned. She’s a very strong technical actress, and it’s because she’s so smart. She’s acute. She’s got a mind like a razor blade.
A few caveats
Of course this entire analysis assumes idea density is a good measure of intelligence. While the Nun Study showed that idea density in youth does an impressive job predicting intelligence and Alzheimer’s in old age, one can’t necessarily assume that idea density is a good measure of pre-elderly intelligence. Although it’s normally true that if a test predicts intelligence decades later, it does an even better job predicting intelligence contemporaneously, one of the ironies of the Nun Study is that idea density measured in youth failed to correlate with the nuns’ academic grades in youth. This may suggest that idea density is a very sensitive measure of intelligence that can be impaired by the smallest tangles in the brain many decades before the tangles increase to the point of diminishing intelligence on the whole. If so, idea density in the relatively young may be a poor measure of contemporaneous intelligence, but an excellent measure of how well one will maintain their intelligence with age.
The strongest evidence of Oprah having extremely high intelligence all comes from when she was extremely young (she could read, write, recite, and do arithmetic by age 3). And idea density suggests she will have extremely high intelligence when she is extremely old (relative to the elderly). And yet during her peak intellectual years (late teens), she studied only easy subjects at a very modest college. Perhaps extremely precocious toddlers regress to the mean in young adulthood, only to come home to their original brilliance in old age. But of course, drawing such sweeping conclusions from largely anecdotal evidence involving only one person would be extremely foolish.
In the book A Question of Intelligence (pg. 140) by Daniel Seligman, he writes:
I spent some forty years as a writer and editor of Fortune magazine and during that time met hundreds of CEOs. Not all of them proved entirely lovable, and some of them were not particularly interesting when asked for opinions on social and political issues remote from their business concerns. But I cannot recall ever meeting a CEO who did not come across as highly intelligent.
Which is understandable. To get the job, executives must have tackled a fair number of complex business problems in the early and middle years of their careers and demonstrated an ability to think strategically about those problems. They must have avoided the screwups that inevitably overtake the not-so-smart. Executives also tend to need verbal reasoning skills. It helps in particular to have the ability to dominate the argument in meetings with peers and colleagues, something not possible if you keep getting your facts wrong and your logic muddled.
In the high quality journal Intelligence, scholar Jonathan Wai estimates that about 39% of Fortune 500 CEOs are intellectually gifted. For the purpose of Wai’s study, gifted was defined as the top 1% (IQ 135+), however I’ve argued that Wai’s methods actually defined gifted as the top 3% (IQ 128+).
If CEO IQ is normally distributed with a standard deviation of roughly 15 (which might be too high for a specific occupation, though there’s a lot of variability in the type of companies they run), then the fact that 39% have IQ’s of at least 128 suggests that the average Fortune 500 CEO has an IQ of 124. This suggests that the large majority of CEOs are highly intelligent (IQ 120+), but I think Seligman overstates his case in implying that out of the hundreds of CEOs he’s met, all were highly intelligent. They probably all seemed highly intelligent because he was only talking to them about their area of expertise: business. However assuming a bell curve, it’s quite likely that some of them are not intelligent at all; indeed some CEOs have made collosally stupid mistakes which cost their companies billions.
An average IQ of 124 also makes sense because it lower than an IQ of 130, which is what I’ve previously estimated to be the mean of self-made billionaires and U.S. presidents. A Fortune 500 CEO makes billion dollar decisions, but a self-made billionaire actually figured out how to get billions which is far more impressive, thus we should expect the self-made billionaire to be smarter. And CEOs may run Fortune 500 companies, but the president of the United States is the CEO of the world’s most powerful country, so U.S. presidents should also be smarter than Fortune 500 CEOs.
The IQ’s of female Fortune 500 CEOs
Jonathan Wai found that among female Fortune 500 CEOs, the frequency of giftedness was even higher, an astonishing 59%. If 59% have IQ’s of 128+, then, assuming a Gaussian distribution with an SD of 15, that implies that the average female elite CEO is brilliant, with an IQ of 131. This makes sense because sexism and other cultural barriers make it harder for women to rise to the top in a male dominated world. Throughout history, the vast majority of powerful women have been the daughters or wives of powerful men (i.e. first ladies). So women who achieve great power on their own are likely to be extraordinary individuals. It’s been reported that Canada’s first female prime minister Kim Campbell scored perfect on a childhood IQ test, giving her an absolutely breathtaking IQ of about 154+, making her likely more intelligent than every single president in American history. As Campbell herself would say, “in order for a woman to be considered half as good as a man, she must be twice as good. Fortunately that’s easy!”
There are a lot of problems with how we measure intelligence. Some people measure intelligence using childhood ratio scores (if a 10 year old is as smart as a 12 year old, he gets an IQ of 120, since he’s functioning at 120% of his chronological age). Other people measure IQ with deviation scores, so if a 10 year old is smarter than 90% of 10 year olds, he’s assigned an IQ of 120. Some tests define the population standard deviation at 15, others 16, others 22 or 24.
About the only thing all IQ tests agree on is that the average score is 100. But the average 20 year old is far smarter than the average 3 year old, so assigning them both an IQ of 100 gets confusing. We must clarify that 100 is the average IQ for one’s age. But IQ’s vary enormously from country to country. So an IQ of 100 is said to represent the average in America, or is it Britain? It depends who you ask. And what happens as demographic shifts cause the populations of both countries to change? What long-term consistency is there in defining IQ 100 as the American average. And what about the Flynn Effect? Average IQ has gone up by some 30 points since the Victorian era yet the average IQ is still 100? And what about dysgenics? Average IQ has gone down by 15 points since the Victorian era yet the average is still 100? I get a headache just keeping it all straight.
And is an IQ of 100 really twice as smart as an IQ of 50? Is a 10 point difference between an IQ of 120 and 130 the same as a 10 point difference between IQ 80 and 70?
Clearly, a much simpler scale is needed:
Around the turn of the millennium, a member of the unbelievably brilliant Prometheus society published one of the most interesting and important articles in the history of psychology, and amazingly, virtually no one has ever read it. The article asserted that problem solving speed doubles every 10 IQ points. The Promethean would later go on to revise the figure to every 5 points. Yes, reaction time (information processing speed) has a beautifully Gaussian distribution, but because the human mind operates in parallel, an IQ 105 is not 5% smarter than an IQ of 100, but rather twice as smart! And an IQ of 110 is four times smarter! Although the Promethean never put it in those terms, this inference was based upon the fact that no matter how cognitively homogeneous a classroom, the difference in learning speed is always at least an order of magnitude. Think back to your high school math class. The brightest kid in the class grasped what the teacher was talking about in seconds, while the dullest may take all year.
So I propose a new intelligence scale to reflect these huge differences. We could call the units of the scale BP scores (Brain Power scores) to differentiate them from IQ scores. We must first anchor our scale to some clear definable unambiguous stable level. I say, the intelligence of the average adult ape in its peak years. To the best I can determine, the average ape has a deviation IQ of 40 (sigma 15). So let’s arbitrary assign the average adult ape (IQ 40) a BP score of 1, and then double the BP for every 5 points above 40.
Thus the conversion between IQ scores and BP scores is as follows:
IQ 40 = BP 1
IQ 45 = BP 2
IQ 50 = BP 4
IQ 55 = BP 8
IQ 60 = BP 16
IQ 65 = BP 32
IQ 70 = BP 64
IQ 75 = BP 128
IQ 80 = BP 256
IQ 85 = BP 512
IQ 90 = BP 1,024
IQ 95 = BP 2,048
IQ 100 = BP 4,096
IQ 105 = BP 8,192
IQ 110 = BP 16,384
IQ 115 = BP 32,768
IQ 120 = BP 65,536
IQ 125 = BP 131,072
IQ 130 = BP 262,144
IQ 135 = BP 524,288
IQ 140 = BP 1 million
IQ 145 = BP 2 million
IQ 150 = BP 4 million
So the average American (IQ 100) would have a BP of about 4000, meaning they’re 4000 times smarter than an ape. The average Ivy league graduate (IQ 130) would have a BP of about 262,000, meaning they’re 262,000 times smarter than an ape. And the average academic Nobel Prize winner (IQ 150) would have a BP of 4 million, meaning they’re 4 million times smarter than an ape. And if intelligence gaps really are as huge as this scale implies, then no wonder we have so much economic inequality!
In the excellent journal Intelligence, scholar Jonathan Wai attempted to estimate what percentage of American elites (billionaires, senators, Fortune 500 CEOs, federal judges) are intellectually gifted by counting how many of them attended elite schools (i.e. schools that recruit students with extremely high scores on tests like the SAT, LSAT, and GMAT). So for example, Wai found that 45% of U.S. billionaires attended elite schools and thus concluded that 45% are intellectually gifted.
At first glance that sounds incredibly simplistic. For many mediocre minds attend elite schools because they have rich and powerful parents or because they win athletic scholarships or are unusually driven. Conversely, many brilliant minds attend mediocre schools because they lack those advantages or just want to stay in their home towns. But Wai cleverly argued that both kinds of exceptions cancel each other out in the aggregate data. So while one can’t tell if any specific individual is gifted from the college they attended, one might be able to tell how many gifted people are in certain groups (i.e. billionaires) from how many elite college alumni are in those groups.
For the purpose of Wai’s study, gifted can be defined as the top 1% in intelligence (IQ 135+) because Wai argued that that’s the level of ability the average elite college alumni has. So since 45% of U.S. billionaires attended elite colleges, 45% should be IQ 135+. If nearly half of U.S. billionaires are 135+, the average U.S. billionaire should be nearly 135.
Is that plausible? As of 2013, there were 424 billionaires in America out of 242 million adults, which means billionaires are about one in half a million. Given that rarity, if there were a perfect correlation between IQ and money, the dumbest billionaire would have an IQ around 169, and the average billionaire would have an IQ of 172 (72 points above average!). But since the correlation between IQ and earnings is not perfect, but rather it’s 0.4, we multiply those 72 points above 100 by 0.4, which gives the average billionaire an IQ of 129 (similar to what I’ve previously estimated using a different method).
But not all billionaires got rich through earnings. About a third inherited a big chunk of it from their fathers or husbands. If the average billionaire has an IQ of 129, the heirs of billionaires would have IQ’s around 113 given the 0.42 to 0.45 IQ correlation between a man and his child or a man and his wife, respectively (I’m focusing on men because they’re the vast majority of self-made billionaires, especially in past generations). In other words, the heirs of billionaires regress to the mean, keeping only 42% to 45% of each IQ point above 100 that was needed to make that money, which is why in a few generations, the money is almost all gone.
So if roughly two thirds of billionaires are self-made (IQ 129) and the remaining third are legacies (IQ 113) the average IQ of all billionaires would be 124. Roughly 10 points less than Wai’s methodology would estimate using elite school attendance rates.
Why does Wai’s method seem to overestimate? In my humble opinion, it’s because Wai overestimates the IQ of elite college alumni. While it’s true that elite college students average the equivalent of IQ 135+ on tests like the SAT, where they average 1400+, those colleges explicitly select for high SAT scores. When you select for people who did extremely well on a particular test, you get a lot of people who over-performed on that one particularly test but will regress dramatically to the mean when given tests that weren’t used to select them. An excellent study by Meredith Frey and Douglas Detterman found that SAT scores have corrected correlations of about 0.8 with other measures of intelligence, so we would expect people who were selected to have an average IQ equivalents of 135+ on the SAT, do be only 80% as far above the mean on official IQ tests (IQ 128+). Indeed I’ve previously blogged about how Harvard students average an IQ of 128 when you move them from the SAT (where they score through the roof) to a more neutral test like the abbreviated Wechsler.
So I think Wai was correct in asserting (based on elite college attendance) that 45% of billionaires are intellectually gifted, but only if he redefines gifted from 135+ to 128+. If 45% are 128+, then the average billionaire would drop from the mid 130s to the mid 120s which makes sense given that many inherited their wealth.
This revised approach also makes sense when you look at U.S. presidents. An astonishing 2/3rds of recent presidents have attended schools Wai classifies as elite, but there’s no way 2/3rds of recent presidents were above IQ 135. That would imply their average IQ is an incredible 140 (10 points higher than they actually seem to score on average). On the other hand, it’s quite plausible that roughly 2/3rds are above IQ 128.
Bill Clinton’s best selling autobiography provides historiometric data
In a previous post, I talked about historiometric IQ’s (used to estimate the intelligence of historical luminaries such as Sir Francis Galton and recently, H.P. Lovecraft) where intelligence is often estimated from biographical, retrospective descriptions of a person’s intellectual precociousness or backwardness, especially in childhood.
Bill Clinton for example, was taught to read at age three by his grandparents. Since most children don’t read until age six, one could retrospectively estimate Bill’s childhood verbal ratio IQ at an astonishing 200, since at age three, he was, by this measure, verbally functioning at 200% his chronological age. Is it plausible that Clinton had a verbal ratio IQ of 200? The media seems to think so. Pundits gush about him being a political genius and former talk show king Phil Donahue once described Clinton as the most verbally skilled president to ever occupy the white house, citing his ability to dazzle in any venue, from a presidential press conference to a black church. It’s even been reported that Clinton has a photographic memory and can solve the New York Times crossword puzzle with superhuman speed, though such anecdotes should be interpreted cautiously since there’s a lot of propaganda in politics.
During his presidency, Clinton’s surrogates like James Carville would routinely appear on TV ranting and raving about how brilliant Clinton is, saying “he’s the smartest person in the room! I don’t give a goddamn who’s in the room. It could be a room full of politicians, it could be a room full of Nobel prize winners. If he’s in the room, he’s the smartest person in the room!”
In his autobiography, Bill Clinton claims he studied algebra in the eighth grade (age 13?) which was unusual since it’s typically taught in the ninth grade (age 14). So Clinton was mathematically functioning at 108% of his chronological age, suggesting a math ratio IQ of 108. However since typically only college bound kids (average IQ 105) study algebra in even the ninth grade, we should multiply this IQ by 1.05. Doing so raises Clinton’s math ratio IQ to 113
This however might be an overestimate because on the same page of his autobiography, Clinton claims that he had to stop helping his daughter with her math homework when she reached the ninth grade (age 14?) because it had become too advanced for him. A grown man incapable of helping a 14-year-old with her homework would imply he was mathematically functioning at less than 88% of adult age (16+), implying a math IQ of 88. But we should remember that his daughter attended an extremely elite school attended by the children of presidents. Since presidents seem to average IQ’s around 130, and the parent-child IQ correlation is 0.42 (see pg 348 of Arthur Jensen’s The g Factor), we should expect a school full of children of presidents (and comparable elites) to have a mean IQ of 0.42(130 – 100) + 100 = 113. So the math homework was geared at 14 year olds with an IQ of 113, which means we must multiply the estimated math IQ of 88 by 1.13, which raises it to 99. If we average this 99 with the previous math ratio IQ I derived from the age when Clinton learned algebra, we get an aggregate math ratio IQ of 106. If we average this aggregate Math ratio IQ of 106 with the Verbal ratio IQ of 200, we get an overall ratio IQ of 153.
Of course ratio IQ’s (mental age/chronological age) are no longer used because different mental abilities develop with age at different rates, and the rates are not linear throughout all of childhood and adolescence, and some children show sudden huge cognitive growth spurts before returning to a more normal growth rate. Because of such inconsistencies, ratio IQ’s give sloppy results, especially at the extremes, and have been replaced by the deviation IQ where all scores are forced to fit a normal curve at all ages and all ranges with a mean of 100 and a standard deviation of usually 15. According to John Scoville, a ratio IQ of 153 has a normalized Z score of +2.84, which means it’s equivalent to a deviation IQ of 143, when the U.S. population SD is set at 15 (Scoville prefers to set it higher).
An IQ of 143 is incredibly high, making Clinton roughly 1 SD smarter than the average U.S. president, who is likely roughly 2 SD above the average American. Bill Clinton is widely described by the media as the most politically skilled person of our life time, so him having an extreme IQ of 143 suggests social intelligence and charisma might be fairly g loaded. On the other hand, Clinton seems more the exception than the rule, as a great many high IQ people are socially awkward nerds. A likely reason for this is that most high IQ people are K genotypes, and being highly evolved, lost primitive parts of intelligence like social cognition that are useful in prolific mating, to make room for more g loaded and technological parts of intelligence. By contrast Clinton, who was born illegitimate, has half-siblings, and lacks sexual restraint, is likely a genetic throwback to our archaic r genotype ancestors. That unique combination of a highly evolved IQ with a primitive social instincts and r genotype personality gave Clinton an incredible competitive advantage in life, and allowed him to rise from the backwoods of Arkansas to leader of the planet in record time. Oprah, who also shows an unusual number of r genotype traits for a smart person (teen pregnancy, illegitimate, half-siblings) is probably another example of that unique combination of traits causing spectacular success.
It should be noted that Clinton was a National Merritt Scholarship Semifinalist, an honor that is given to students who score extremely high (perhaps the equivalent of IQ 138+) on a test of academic ability. So the historiometric estimate is validated by an actual IQ score.
In the book, A Question of Intelligence by Daniel Seligman, he reports (pg xiv) that the correlation between IQ and elementary school grades is 0.65. This correlation is far from perfect since how hard you work is just as important to grades as how smart you are, but the correlation is still very high (as high as many IQ tests correlate with each other). The correlation drops in high school and drops further in university, but that’s probably because as you move up the educational ladder, a lot of low IQ people drop out, so there’s less IQ variation for grades to correlate with. But in elementary school, you have virtually the full range of cognitive ability, so it’s a good place to understand the true relationship.
So in a typical elementary school class, you might have 30 students, which means that the lowest IQ in the class should be 28 points below average and the brightest in the class should be 28 points above average (IQ 72 and 128 respectively). However because IQ and grades “only” correlates 0.65, the best and worst students in the class should have IQ’s only 65% as extreme: 82 and 118 respectively.
Of course, elementary school grades are only one way we can quantify academic success in the general population. Another way is years of schooling or highest degree obtained. In the U.S., a PhD roughly marks the top 1% in years of completed education, which suggests that the median PhD is in the top 0.5% in education level. If there were a perfect correlation between IQ and academic success, we’d expect the average PhD to have an IQ of 138 (the top 0.5%), but since the correlation is “only” 0.65, each point above 100 must be multiplied by 0.65, reducing the average PhD to their actual IQ which is around 125 (still very high!).
IQ’s of Harvard students
Are there academic achievements more impressive than getting a PhD? Yes. Getting acceptance into Harvard: the world’s most prestigious university. Out of the 4.1 million 18-year-olds in the U.S. in a given year, only about 1600 go to Harvard. So if there were a perfect correlation between IQ and academic success, the dumbest Harvard student would have an IQ of 150 and the median might have an IQ of 153. However because the correlation is only 0.65, the median Harvard student should be only 65% as far above 100. Thus, simple regression predicts the typical Harvard student should have an IQ of 134. Actually a sample of Harvard students studied by Harvard psychologist Shelley Carson and her colleagues scored somewhat lower on an abbreviated version of the Wechsler intelligence scale:
Eighty-six Harvard undergraduates (33 men, 53 women), with a mean age of 20.7 years (SD = 3.3) participated in the study. All were recruited from sign-up sheets posted on campus…The mean IQ of the sample was 128.1 points (SD = 10.3), with a range of 97 to 148 points
On the other hand, the average Harvard student has an post-1995 SAT score (reading + math) of 1490, which according to my formula equates to an IQ of 141.
The SAT likely overestimates Harvard intelligence because when you select people who did especially well on one test, you are also selecting people who got lucky, were well prepared and overperformed on that one test. Such people will likely regress to the mean when given a test that wasn’t used to select them. On the other hand the abbreviated WAIS may have underestimated Harvard students because it’s a very brief test, and thus gives only rough results. Averaging their scores on both tests, gives an IQ of about 135. Almost identical to what simple regression predicted based on the 0.65 correlation between IQ and academic success.
IQ’s of tenured professors
Another form of academic accomplishment that’s about as exclusive as attending Harvard is becoming a tenured university professor. Scientist Steve Hsu wrote:
…when an attorney prepares a case it is for her client. When a Google engineer develops a new algorithm, it is for Google — for money. Fewer than one in a thousand individuals in our society has the privilege, the freedom, to pursue their own ideas and creations. The vast majority of such people are at research universities. A smaller number are at think tanks or national labs, but most are professors…
So in terms of academic success, being a full tenured professor is a one in thousand level accomplishment. If there were a perfect correlation between IQ and academic success, the dumbest tenured professor would have an IQ of 147, and the average tenured professor would probably be around 150. But since the correlation is 0.65, we should expect the average tenured professor to be around 133 with quite a bit of variability around that mean, depending partly on the prestige of the university they teach at and the g loading of the subjects they teach.
IQ’s of Nobel Prize winners
Are there academic accomplishments more impressive than becoming a professor or going to Harvard? Yes: Winning the Nobel Prize. Many years ago a respected psychometric expert named Garth Zietsman wrote an article about using this type of regression to estimate the IQ’s of Nobel laureates, though I don’t remember the exact stats he used.
But let’s say only one in a million American adults has a Nobel prize (excluding the Nobel peace prize which is non-academic). If there were a perfect correlation between IQ and academic success, we’d expect the dumbest American Nobel laureate to have an IQ of 171 and the average Nobel laureate to be around 174. But again, since the correlation is 0.65, the average Nobel laureate should have an IQ of 148, or roughly 150 if you like nice round numbers. Of course there would be a lot of variability around the mean. Those who earned their Nobel prize in hardcore intellectual subjects like physics would likely average above 150. Those who earned their prize in more subjective and artistic subjects like literature would likely average well below 150; indeed probably below 140.
Is it plausible that the average academic Nobel prize winner has an IQ around 150? Yes: In the early 1950s, Harvard psychologist Anne Roe intelligence tested extremely eminent scientists who were very close to Nobel Prize level. She found they had an average Verbal IQ of 166, an average Spatial IQ of 137, and an average Math IQ of 154. These are very inconsistent results suggesting there might have been problems with how the tests were created and normed. Nonetheless, if you average the three scores to cancel out the error, you get an IQ of about 150.
Psychologist Lewis Terman pioneered a historiometric approach to IQ assessment, in which the IQ of a historical figure is estimated from biographical data with an emphasis on childhood precocity. So while reading a biography of mental testing pioneer Sir Francis Galton, Terman noted that between the ages of three and eight, Galton was intellectually functioning at twice his chronological age, and thus assigned him an astonishing ratio IQ of 200 since Galton’s cognitive development was progressing at 200% of the normal rate.
Terman’s analysis of Galton would lead to the Cox study in which the IQ’s of about 300 historical figures were estimated from reading their biographies, and more recently, there was an interesting historiometric attempt to estimate the IQ of horror author H.P. Lovecraft.
In a biography of Oprah called Oprah Winfrey: The Real Story by journalist George Mair (pg 8), it’s reported that Oprah’s grandmother taught her to read, write and do arithmetic by the time she was three. Also at the age of three, Oprah stood before the church congregation and said:
Jesus rose on Easter Day. Halelu, halelu, all the angels did proclaim!
Based on her ability to learn and recite, it sounds like Oprah at the age of three was functioning verbally at the level of a five or six year old. Based on this I would assign her a Verbal ratio IQ of 183 since her verbal skills were developing at 183% of the normal rate.
Now in this video, Oprah interviews her fourth grade teacher. Oprah claims that in the fourth grade, she found long division difficult, however her teacher doesn’t recall Oprah struggling with anything and claims she grasped concepts readily. The truth is probably somewhere in between, so let’s assume Oprah learned long division as quickly as the average fourth grader. However Oprah skipped Kindergarten and second grade so she was younger than her classmates, though only one year younger because she was born in January. So while most kids are learning 4th grade math (long division) at age nine, Oprah was learning it at age eight. This means her math skills were developing at 113% the normal rate which gives her a math ratio IQ of 113.
Averaging her Verbal ratio IQ of 183 with her Math ratio IQ of 113 gives an overall ratio IQ of 148, or roughly 150. According to scholar Vernon Sare, one in 286 children had ratio IQ’s this high or higher (the top 0.3%).
On modern IQ scales (known as deviation IQ scales), scores are forced to fit a normal curve with a mean of 100 and an SD (standard deviation) of usually 15, which means the top 0.3% equates to an IQ of 141. So Oprah would have a deviation IQ of about 140, which is precisely what one should statistically expect for someone of her background, brain size, and success level.
Of course, an extremely high childhood IQ does not always turn into an extremely high adult IQ. However new research shows that when childhood IQ is measured accurately, it’s actually far more predictive of adult IQ than traditionally thought.
The National Enquirer, May 14, 1996, reporting on Oprah’s stratospheric head size
My head is so big I have to wear TWO wigs
– Oprah Winfrey, 1996
I’ve been told that when one talks about intelligence, there are so many different parts to it. It’s pattern recognition, memorization, verbal ability, spatial ability, numerical ability, social comprehension, musical talents, self-awareness, lateral thinking, logic, intuition, and so much, much more. But if one wants a single umbrella to cover ALL of intelligence, then some say it’s the ability to adapt; to take whatever situation you’re in, and turn it around to your advantage. The adaptative value of intelligence is demonstrated by the fact that brain size nearly tripled in just the last 4 million years, from 500 cm3 in Australopithecenes to 800 cm3 in Homo habilis to 1000 cm3 in Homo erectus to about 1350 cm3 in modern Homo sapiens (higher in the developed world where nutrition is good).
So the reason humans are considered the most intelligent animal is that despite having so many disadvantages (we lack fur, strength, speed, claws, sharp teeth, wings) we were able to adapt the world to our advantage. We didn’t have fur, so we created fur coats. We didn’t have claws, so we created knives. We couldn’t run fast, so we created cars. We didn’t have wings, so we invented airplanes etc. We were able to use plants to our advantage (agriculture) and animals to our advantage (domestication) and subdue and capture animals like gorillas who are many times our size and strength. So despite being such a weak disadvantaged animal, our freakishly large brains allowed us to become the most powerful and prosperous animal on the planet.
Analogously, Oprah had almost every disadvantage. She was born a poor dark skinned black female in Jim Crow rural Mississippi (the lynching capital of the world). She was illegitimate, sexually abused, became overweight, and was not considered pretty. Yet she was able to adapt all these disadvantages to her advantage. She used her weight problems to bond with millions of Americans. She shared her sexual abuse to help lead millions of abuse victims to recovery. She very skillfully used her race to become America’s black best friend. She used her poor upbringing to gain sympathy. Pretty soon, Forbes magazine was ranking her as the richest self-made woman in America, and some years, arguably the world.
But Oprah didn’t just achieve wealth (economic capital), she also achieved status (social capital). Time magazine ranks her as the most influential woman on the planet. When millions of Americans voted in 2005 to elect the Greatest American in history, Oprah was the only female to make the top 10, making her at that moment, the most worshiped woman ever within the world’s sole superpower, and perhaps as a corollary, the most powerful woman in the world. A woman so powerful that when she was disrespected by a clerk in Switzerland, the country officially apologized. Books she recommended would become colossal bestsellers, and some economists credit her with almost single-handedly putting a black man in the white house.
New York Times columnist columnist Maureen Dowd stated:
She is the top alpha female in this country. She has more credibility than the president. Other successful women, such as Hillary Clinton and Martha Stewart, had to be publicly slapped down before they could move forward. Even Condi has had to play the protegé with Bush. None of this happened to Oprah – she is a straight ahead success story.
And Bill O’Reilly said:
this is a woman that came from nothing to rise up to be the most powerful woman, I think, in the world. I think Oprah Winfrey is the most powerful woman in the world, not just in America. That’s – anybody who goes on her program immediately benefits through the roof. I mean, she has a loyal following; she has credibility; she has talent; and she’s done it on her own to become fabulously wealthy and fabulously powerful.
So just as humans overcame adversity to become the world’s most prosperous and powerful animal, Oprah overcame adversity, to become the world’s most powerful and prosperous woman. Just as humans were able to outdistance all other animals because we’re the world’s biggest brained animal (relative to body size), arguably Oprah was able to outdistance all other women, because she’s arguably the world’s biggest brained woman.
The world’s biggest brained woman?
I have heard Oprah state on her show that she has to have her hats custom made because her head measures 25.25 inches around, a cranium so large that two wigs had to be sewn together to fit her for her Oscar nominated performance in The Color Purple. This equates to 641.4 mm. According to the U.S. Army Anthropometric Survey Database, by Claire C. Gordon (Final Report, October 1996), in 1995, a sample of 3,482 active duty females in the U.S. army had their heads measured. The mean circumference was 546.6 mm and the standard deviation (SD) was 15.1. Assuming this sample is roughly representative of adult female U.S. crania, Oprah’s head perimeter is 6.3 SD above the mean of American women. Assuming a Gaussian distribution, fewer than one in five billion women in America should have cranium that large. There are of course, not five billion women in America or even the world, let alone the developed world where nutrition is optimum for brain growth; thus Oprah has arguably the world’s largest female cranium (excluding female hydrocephalics, where head enlargement reflects cerebrospinal fluid not brain mass, and autistic females, where enlargement reflects a brain that was super-sized in childhood, before shrinking in adolescence).
Of course head circumference is just a crude proxy for brain size. Some formulas very crudely attempt to make the conversion. For example the late Professor J. Phillipe Rushton argued that a simple conversion would be to use the formula for calculating the volume of a hemisphere (V = circumfence3/118.4). Plugging Oprah’s 64.14 cm head circumference into this equation gives a cranial capacity of 2,229 cm3, a truly unimaginable figure. However Rushton only validated this formula in young Asian children; he never approved it for adults or all races. One reason why it might give exaggerated results in adults is that it does not subtract the fat and skin around the skull which is thicker in adults than in children and probably adds 200 cm3. Subtracting those 200 cm3 brings Oprah down to 2,029 cm3.
The biggest brained member of both her race AND her gender?
If it weren’t astonishing enough that Oprah is arguably the world’s biggest brained woman (or at least arguabley was in her youth when her brain size was maximized and the world population was lesser), she is/was also arguably the world’s biggest brained black. Professor Rushton found that a sample of 2,676 African-American Army personnel measured in 1988, had a mean cranial capacity of 1,362 cm3 (SD = 95). Assuming this sample is representative of black people reared in the developed world, Oprah’s estimated cranial capacity of 2,029 cm3 would be 7 SD above their mean, implying a normalized rarity of less than one in 190 billion! Of course this is not a perfectly apples to apples comparison since the brain sizes of the black Army personnel were estimated from head length, head breadth and head height, while I have estimated Oprah’s brain size from circumference, and differences in head shape can give different estimates of cranial capacity. But it’s also worth noting that if adjustments for fat-free body weight were made, Oprah’s cranium would be even more impressive, because in mixed-sex comparisons that are not adjusted for body size, women are penalized because head size correlates moderately with fat-free mass of which women have much less.
The World’s only black billionaire?
If it weren’t astonishing enough that Oprah is arguably the world’s most powerful and prosperous woman (or at least was at the peak of her and America’s power), she is/was also arguably the world’s most successful black. She is almost always the only African American on Forbes annual list of the 400 richest Americans and her estimated net worth of $2.9 billion makes her the richest African American of all time.
From 2004-2006, she was one of only three blacks on Forbes annual list of all the billionaires in the world (not just America). However the other two black billionaires may not have been of predominantly black ancestry. One was Saudi Arabian Sheikh Mohammed Hussein Ali Al Amoudi, whose father is from Yemen (a population that is typically Middle Eastern, not black). While his mother is from the black nation of Ethiopia, geneticist Cavalli-Sforza estimated that nearly half of that country’s genes originated in West Asia rather than black Africa. Given both parents, it’s very possible that Al Amoudi is of predominantly Caucasoid ancestry.
The other black billionaire was Canada’s Michael Lee-Chin, who has two Jamaican grandparents, and two East Asian grandparents. Seeing as Jamaicans are not of purely black origin (there is non-trivial white admixture) and two of his grandparents are from cold East Asia (the opposite of sub-Saharan Africa), it’s likely that Lee-Chin is also less than 50% black at the genetic level. Perhaps because of the racial ambiguity of the two men, Oprah was for several years regarded as the only black billionaire in the world, not just in America, though in recent years, a few other unambiguously black billionaires have emerged in Africa.
At least in America, self-made billionaires tend to be brilliant. Ultra-big brained people tend also to be brilliant. Since Oprah is both a very self-made billionaire and likely an ultra-big brained person, statistically she is likely to be especially brilliant. Though Oprah has made billions off her populist image as an average woman, and seems brutally honest about her cognitive shortcomings, evidence of exceptional intelligence can be found in her childhood. During her formative years, she was raised by her grandmother, Miss Hattie Maie (a maid) in rural Mississippi, where Oprah was reading and reciting Bible verses by age three. Oprah fondly recalls how the women at the all black church where Oprah would give recitations would turn to her grandmother and say: Miss Hattie Maie, that child sure can talk. That child’s gifted. That child’s gonna talk her way out of Mississippi.
Jealous of her talents and resentful of her messiah complex, the other kids would later derisively nickname her “the preacher”, a la Stephen King’s Children of the Corn and attempt to beat her up, but the adaptable young Oprah would always talk her way out of it.
At age six, she recalls writing her Kindergarten teacher a note that said:
Dear Miss Newe,
I do not belong here because I can read and I know a lot of big words: Elephant, hippopotamus.
She was quickly moved to first grade, and would go on to skip the second grade too.
[Addendum, July 8, 2014: this post is a revision of an article I published many years ago]
Brain Size 