January 27, 2013

Regression toward the mean and IQ

A reader sends me an Excel file for calculating expected IQs of children based on their parents' IQs. 

As I've been pointing out for a long time, these questions are of particular interest to the infertile and to lesbians. (I coined the term "lesbian eugenics" to summarize the issues that lesbian would-be mothers confront in picking a sperm donor, but it hasn't caught on. After all, as we all know, lesbians are Good and eugenics is Bad, so ... Does Not Compute!)
I am an avid reader of your site for ~10 years (not even sure since when) and wanted to email you about a Steve Sailer / Steve Hsu inspired analysis I did over the weekend ... The topics are intelligence, heredity and mating (I am 32 year old single male considering the best course of action).

The best course of action is probably to find somebody you like talking to because you are going to be doing that for a long time. But, all this stuff is definitely interesting.
This is is based on a presentation by Steve Hsu entitled "Investigating the genetic basis for intelligence".

On slide 19 of the presentation, with the header "Your kids and regression" Steve writes "Assuming a parental midpoint of n standard deviations above the population average the kids' IQ will be normally distributed about a mean which is around +0.6n with residual standard deviation of about 12 points." He also gives a helpful example immediately below "So, e.g., for n=4 (parental midpoint of 160 - very smart parents!), the mean for the kids would be 136 with only a few percent chance of any kid to surpass 160 (requires +2 standard deviation fluctuation)."

I've seen estimates of the "narrow sense heritability" of IQ ranging from 0.34 to 0.86. At the lowest figure, the two 160 IQ parents' children would average 120 and at the highest, 152. But, as my reader points out, for most values in the middle of that range, the implications he draws are still more or less true.

Another thing to keep in mind is that this assumes that the IQs of grandparents and earlier ancestors are unknown. In contrast, the Darwin-Wedgwood-Galton-Keynes-Benn-Vaughan Williams extended family seems to regress toward a higher IQ than 100, as do the Huxley-Arnolds.

Here are some implications the reader draws, assuming a 0.6 figure.
1) Mating insight

Many nerdy or high achieving men bent on reproducing are troubled by the fact that most intelligent women want a career and likely do not want to have children (or want to adopt orphan baby at age 50, once they have “made it”). Women who are slightly less intelligent may want to have families and even to have bigger families. The above Excel file lets one see the impact of say a man with an IQ of 140 marrying a woman with an IQ of 140 and having only one child (whose expected IQ would be 124) vs. that same man marrying a woman with an IQ of 120 and having three children. The second man's highest IQ child will have an expected mean IQ of 128 which is higher than the man who married the smarter woman but had only one child. Even if the smarter woman chooses to have two children the two smartest children out of the three children that the less intelligent woman had will have approximately the same expected IQ as the two children of the high IQ woman.

Takeaway - twenty IQ points is a lot: 120 vs. 140 is a big difference and it will be by definition much harder to find a woman with an IQ of 140+ (one in 261) vs. one with an IQ of 120+ (one in 11) and it will be much more difficult to persuade your wife to give up IQ 140-career track (Fortune 500 CEO, Ivey League tenured professorship etc.) than IQ 120-career track (nurse, high school teacher etc.) for changing diapers in the middle of the night. If one is concerned about having one or two competent kids to whom one can leave the family business to one might consider finding a slightly less intelligent woman who is willing to have a few kids. Of course there are other factors. Having more children means giving each child less attention but spacing births helps mitigate this and we know that nature dominates over nurture in this matter anyhow. Not to mention that having only one child can result in tragedy if god forbid something was to happen to it.

2) The speed of the regression to the mean.

If one starts with two parents whose IQs are 160 and looks at the average IQs across generations the speed of the regression to the mean is quite fast.

Parents 160, 160
Children average 136 (assume these mate with a 136)
Grandchildren average 122 (assume these mate with a 122)
Greatgrandchildren average 113 (assume these mate with a 113)

There is already a huge drop between the grandparents and the grandchildren. So in just 4 generations the regression to the mean has brought down the Nobel-prize-level grandparents to the pretty much average intelligence. (all this is of course "on average")

This might be a reason why the intellectual elite might want to pay more attention to making America a country where those with IQs of 110-115 can still live satisfying lives with good middle class jobs and publicly funded services. Chances are that most of their descendants will need those jobs and services only century from now; after all “fool and his money are soon parted” – even if dimmer kids inherit billions chances are that they will not have what it takes to keep the wealth in the long run.  

3) "Geniuses belong to the people"

Imagine that with two parents with IQs of 160 set out to produce one child with the same IQ. How many kids we can expect them to have before they succeed? They would have to have 44 kids to have one kid whose IQ would be 160 or higher on average! This is clearly impossible. And if they set standard to IQ 170 - they would require 434 kids!!! Thus geniuses are really borne out of a people and not out of any two particular parents. Having smart parents helps, a lot, but even then, the chances that your little one is going to be the next Newton are small. Very, very small. On the other hand, according to historians none of Newton’s paternal kinsfolk were able to even sign their names. 
4) "The advantage of the rich - buying IQ points through marriage?"

Say you have a family scion with an IQ of 160 who marries a woman with an IQ of 132 (so top 2%). And then their kid perhaps regresses but he leverages family fortune and name to marry a woman with an IQ of 132 and so on and so on. (Sure he might not be the smartest but he's rich so why not marry him). Assume other generations repeat the same trick. What happens?

In just three generations the IQ falls to 114 and stays there. The 132 woman helps keep it at 114 vs. falling back down but it doesn't go up.

Thus another conclusion, being multi-generational rich helps, you can buy intelligence and ensure that your kids are one standard deviation higher than the average. That is a lot, but it also allows for a lot of overlap between the populations. (Especially because never dipping under the IQ 132 threshold is an optimistic assumption - it assumes multi-generational saintly resistance to blonde bimbo's charms). Thus, richer kids are on average smarter but plenty of them are dumber than the average Joe. 

212 comments:

1 – 200 of 212   Newer›   Newest»
DR said...

One thing that the models need to take into account is the asymmetry in IQ variance between men and women. IQ standard deviation is lower for women then men. Let's say its 12 points for women and 15 points for men. A 160 IQ woman is at +5 sigma, while the same man is only at +4 sigma.

The implication is that a high-IQ mother contributes to a higher IQ offspring than a high-IQ father. For example in the above analysis assume a simple 0.5*(Mother sigma + father sigma).

A mother with a 140 IQ and father with a 120 IQ would produce an expected 117.5 IQ son (+1.16 sigma). In contrast if the situation was reversed with a 140 IQ father and 120 mother the expected IQ of the son would fall to 116.25.

Implication: It's more important to have a high IQ mother than a high IQ father.

Anonymous said...

At some point there's a floor. An ideal, great environment 140 probably has a neutral/natural 115, all shredded and dried out. It's like weight, you have a "frame" size but the best muscle addition to the frame could vary wildly. Pro fighters of the same frame and merit might be 3 weight classes apart, depending on style and what trainers they got early.

But at some point, the probabilities calculus into nothing. 100 natural 115's might produce 1 130, 1000 of them might produce 1 145, but 10000 aren't going to give you a 160; at some point you are limited by your frame. It's just too under the radar. The national/racial IQ needs to be 103ish for the best mix of fertility and potential brilliance. I might be aiming too high, typical European thinking.

Elites are obsessed with caste and underrate race to an absurd degree. Their time (as in generations here) value is that of average people, not gifted ones. THEY ARE AVERAGE PEOPLE, who just happened to grab more than average frontal cortex mass. But memory, spacial, intuition, and other measurements reveal them as being generally normal range, which is what their children will be.

Sincerely bright people aren't elected. Proles don't like a mismatch of time preference or incentives for corruption (and the juicy pork it leads to). A well rounded mind could make a living in 3243 different ways, so there's far less of a tendency to want to cheat (pure wealth doesn't matter here, because it's about social/sexual status dependent on dominance!). A fluke high IQ (and normal everything else) specialist who could rise to the top, with just a little "extra help", has a vastly greater incentive to cheat than a real renaissance man.

Invariably, the former make it in politics, and the latter retires to Thailand at 34. There's 80% of modernity explained for you.

michael lamb said...

Which mean are we regressing to? Usually it is the taken to be the population in general but it has to be the mean of your ancestors. There's no way non-ancestors can affect your IQ, right?

For this reason I think your example of 160 IQ parents having 130 IQ children and 122 IQ grand-children could be pessimistic. I.e. my hunch is that having an iq of 130 with genius parents is more promising than having an iq of 130 with average parents.

Put another way you say:
n0 = 0.6 * n1

I'd propose:
n0 = (c1 * n1) + (c2* n2) + (c3 * n3)...

n0 = childs IQ, n1 parents IQ, n2 grandparents IQ ect.

Anonymous said...

I like the idea of gamete adoption, or, couples adopting the sex cells of others. Most likely sperm. I think men should rethink this whole idea that they must have children that are biologically related to them. Gamete adoption/trading would spread good genes very quickly.

michael lamb said...

Which mean are we regressing to? Usually it is the taken to be the population in general but it has to be the mean of your ancestors. There's no way non-ancestors can affect your IQ, right?

For this reason I think your example of 160 IQ parents having 130 IQ children and 122 IQ grand-children could be pessimistic. I.e. my hunch is that having an iq of 130 with genius parents is more promising than having an iq of 130 with average parents.

Put another way you say:
n0 = 0.6 * n1

I'd propose:
n0 = (c1 * n1) + (c2* n2) + (c3 * n3)...

n0 = childs IQ, n1 parents IQ, n2 grandparents IQ ect.

hbd chick said...

@steve - "The best course of action is probably to find somebody you like talking to because you are going to be doing that for a long time."

yup. sage advice!

(but all the iq calculations were great!)

NOTA said...

How do you incorporate grandparents and previous generations into the analysis?

eah said...

One tip for your correspondent: don't bring this up on the first date.

Anonymous said...

Steve. this is very insightful. But as a wealthy parent, if I set up my sons' trust funds so that they inherit nothing unless their wife has an IQ over 150 and produces three or more children, the power of incentives will work to produce that outcome. There are plenty of very young fertile 150 plus IQ females who are ready to marry a motivated wealthy young man at a young age. In particular if you look at young women at BYU, many of them combine exceptionally high IQ with a desire to start reproducing immediately.

Anonymous said...

This guy doesn't understand genetics, or why regression to the mean happens, and his calculations are wrong. Regression to the mean when you pick exceptional parents reflect that part of their exceptionality is due to factors other than additive variance.

So the mean of the kids mainly reflects the more limited additive variance component. But then we know that the kids have enough additive variance to get their average IQ, on average. So if you crossed that generation with each other they won't regress to the population mean again (there's no platonic essence of population mean that does magical genetic engineering on kids to make them exponentially decay to it).

If they mate with folk of equal phenotypic IQ selected from the population at large (and thus lower additive variance contributions to their IQ) then you will get regression to the mean, but only at half the rate.

Jehu said...

Steve,
If you want smart kids, a smart mother is only the beginning. What you really want is a smart mother who isn't terribly exceptional among her family---ie. you want her to have smart parents and grandparents as well. If you marry a smart one-off, as you imply, regression to the mean is going to be brutal. Besides, your wife's parents become your in-laws. You can't pick your own parents, but you most assuredly CAN pick your in-laws (half of your child's grandparents).

Anonymous said...

Steve, as a shortcut to getting high IQ grandchildren, many parsis require their children to marry other parsis. Since parsis have genetic material that codes for the highest IQ in the world (higher than ashkenazi and higher than northeast asians) this strategy works well

Anonymous said...

Hmmm... could the desire for high IQ grandchildren be the reason both Donald Trump and Hilary Clinton encouraged their daughters to find Jewish men to marry?

Veracitor said...

"more important to have high-IQ mother than father"

Thank your for that insight, though it has depressing implications, since it is high IQ women who are least likely to reproduce. (Also, most of the East Asian men I know believe the opposite, with some strange consequences for their mating strategies.)

Another thing... I grok regression toward the mean but there is still the problem of defining the population whose mean is to be regressed toward. This is why a certain degree of breeding isolation/endogamy defining an otherwise "big enough" (to avoid serious inbreeding depression) population can be so useful-- regression toward a population mean of, say, 105 IQ is a lot less painful than regression toward a population mean of, say, 85 IQ.

Regression toward the mean is the curse of smart parents' lives. It is natural to wish for children as smart as or smarter than oneself but the smarter you are the less likely your wish will come true.

(This all relates to why libertarian economists' views on immigration are so wrong. Libertarian economists have never heard of regression toward the mean, or perhaps are so ideologically blind they don't think it applies to human beings.)

Anonymous said...

Anonymous 1/27/13 2:12 PM is setting his standards too high. There is a good chance that he will reduce the number of his grandchildren. If the inheritance is denied to his children on a technicality or near-miss of the set standards, then they will not be able to support many children. The children they do have will be poor and low in social status, which would hurt their ability to attract mates if male.

Anonymous said...

I'm a high IQ 30 year old single female :) and reader of Steve's site

Ok...I really don't know what my IQ is...but we'll pretend I'm high IQ :) I need the ego boost!

This question bothers me a lot because as my girlfriend says "Do you wait for something better or take what you can get?"

Not to mention, for a female I'm very anti-social. I've gone 3 months without speaking to people with no problem whatsoever. Solitary Confinement = vacation.

After a great deal of thought on this question...I think it's less IQ and more about Morals and Heart.

The reader mentions high IQ women who adopt foreign children. That's not high IQ. One of my college crushes, the smartest man I ever met, he married a good hearted "Mommy Christian" type who ended up being bat shit insane and adopting African children while breastfeeding her white child and shaving her head Britney Spears style.

So...Morals and Shared Values are Much More Important than IQ. If you find a woman who thinks white people stealing black babies is wrong, or immigration is white genocide, or that miscegenation is a sin. You should wife that bitch up.

:)








Anonymous said...

Let's consider the real personalities of high IQ women.

How shall we do this? Well, how about what we know of women in the high IQ populations.

Ashkenazi Jewish women

Women in STEM academia

High IQ Asian women

Now, when you think of these groups, does "great personality for a wife" come to mind?

I am not being sarcastic.

Honest question.

rob said...

Anonymous said...
...I think men should rethink this whole idea that they must have children that are biologically related to them.


I think I should get a free pony. How are the two similar? Neither one will happen.

Anonymous said...

Uh, Hilary isn't likely to get any grandchildren.

Anonymous said...

"Which mean are we regressing to? Usually it is the taken to be the population in general but it has to be the mean of your ancestors. There's no way non-ancestors can affect your IQ, right?"

Exactly. I don't buy the regression to the population average mean expressed by this reader. Our societies are already largely segregated by class and getting more that way. White collar people marry amongst themselves, blue collar people marry amongst themselves, the poor/criminal class marry amongst themselves. Each have a different IQ that is being regressed to. Whatever this spreadsheet calculation is, I suspect that it is wrong for this reason.

In my own family, the IQs already started out high (above 130 in at least one, though I suspect both), but seem to have gone higher on average amongst the children. The next generation don't appear lower either. If this spreadsheet calculation was a useful guide, I would expect that the next generation would be hardly fit to be middle managers or foremen instead of at the top of their class.

It also doesn't match my experience in high school. The brightest kids all had bright parents, and all had at least one very bright parent.

Anonymous said...

I remember reading in Ben Stein's column that he said Richard Nixon believed that intelligence was largely inherited through the mother. My brother and I are high IQ and have very smart paternal relatives and very average maternal ones, so I don't think that's right.

Anonymous said...

We all know that the average "white" person in the USA has an IQ of 100. But I read that the average white person in West Virginia has an IQ of 96. Does anyone know if the West virginia whites regress towards a mean of 96 or whether they regress towards the overall white average of 100?

Anonymous said...

High IQ European women and men are toast in this society. They are for:

1 - Foreign adoption.

Think female celebrities Madonna, Angelina Jolie or Charlize Theron setting the cultural themes for other high status white liberal women. Adopting African and Asian kids and keeping them in your house? So cool man.

2 - IVF.

IVF has a modest success rate since the 1970's. Most of the children end up being autistic, Asperger's, Down's Syndrome or girls, since when a mother is older, her children are more likely to be girls and more likely to have genetic effects. So we have genetic defects, failures and sex ratio skewed towards women. Combine that with the whole strange liberal chivalrous "Father-daughter" relationship, and liberal lifestyles become more entrenched.

3 - Over exercising.

Too much exercise can cause no menstruations in women. And can damage a couple of muscles and bones in men.

And so on.

Anonymous said...

There are plenty of very young fertile 150 plus IQ females


Nope, there is not "plenty" of them. The intersection of the sets "very young" + "fertile female" + "150 plus IQ" is going to be extremely small. Only one person in approx 2,300 has an IQ greater then or equal to 150.

The good news is that both the importance of IQ and its hereditary nature are both wildly overrated around these parts. Extremely intelligent people are commonly born to not-very-intelligent parents. And people with IQ's much less than 150 commonly do very well for themselves in America.

Anonymous said...

could the desire for high IQ grandchildren be the reason both Donald Trump and Hilary Clinton encouraged their daughters to find Jewish men to marry?


I'm not sure why this horseshit makes it through the comment filter. Neither Trump not Clinton "encouraged" their daughters to find Jewish men to marry.

And don't even get me started on the cartoonishly ignorant opinions which many commenters here have about Jews and IQ.

Anonymous said...

But this does have Devastating Consequences for Men who Interracial Marry...

So if a white man marries a black chick then his grandchildren will regress to the average of white and black which is devastating.

Regressing to 110-115 is not so devastating. That's a good life. Regressing to 95...yeah that's bad.

I know what some of you Asian Female Lovers will say "Oh well...my children will regress to a higher mean then even the white children HAHAHAHAHA Suck it!" My answer...Goodluck with that! Haven't seen any exceptionalism from my own part asian family members (all lower than the pure whites) so don't count on it. Besides, standard deviations for asians is lower than white so you'd have to figure that in...plus the fact that half white half asians would have lower reproductive values and more difficulty finding an ideal mate and more probability of marrying hispanic (many half asians look hispanic) or black.

I believe the Uighurs are half-asian half-white and they are on their way out evolution wise.

Anonymous said...

"Hmmm... could the desire for high IQ grandchildren be the reason both Donald Trump and Hilary Clinton encouraged their daughters to find Jewish men to marry?"

Nah ... the Donald was trying to get his daughter married to Tom Brady ...but he wasn't interested.

The Clintons were just hoping that somebody anybody would marry the daughter (Have you seen her? Oy Vey!!).

I think both boys were the sons of Askenazi White collar criminals so great match I guess... espescially in the case of Clinton.

You know birds of a feather etc. ...

Anonymous said...

Why do men equate Madonna, Angelina Jolie and Charlize Theron with High IQ?

I think you guys need to stop thinking with your lower half..beauty does not equal brains.

JSM said...

"In particular if you look at young women at BYU, many of them combine exceptionally high IQ with a desire to start reproducing immediately."

Women are status-seekers.

Mormon women (including the smart ones) choose motherhood because the Mormon church holds mothers in high esteem.

Non-Mormon modern, areligious, women are told by (non-Mormon) society in general that motherhood is low status and that careerism is high-status. Therefore, smart women who are capable of getting the credential that gets the career, choose the career.

Were society in general to grant the status and appreciation to mothers in general that the Mormon Church does to its women, the ensuing baby boom by the smart women would knock yer socks off.

Anonymous said...

The assumed heritability of IQ in the general population is assumed to be 0.6. As I understand it, one would only use this factor if additional information on IQ of previous generations is not known.

For instance, if one knows that both parents are drawn from a limited breeding pool that has been throwing high IQ children for tens of generations, I suspect the heritability factor may be significantly greater than 0.6.

Or, if both high IQ parents are drawn randomly from the general population, and one knows that neither parent has any high IQ ancestors for several generations back, the additional information may imply a heritability factor significantly less than 0.6.

Take home message is that if the aim is to build a population (bloodline) thats breeds selected traits with high levels of certainty, a proven strategy is to line-breed with limited outcrossing under conditions of ruthless culling - environmental or otherwise.

After several generations, breeding within the sub-population will still exhibit regression to the mean for the selected traits, but the mean will have "increased" from the general population mean, and the variance will have decreased. The reduced variance implies greater heritability within the sub-population.

Neil Templeton

Anonymous said...

I know it's totally anecdotal, but I'm skeptical of the regression to the mean averages when it comes to intelligence. I know a fair number of kids of very smart people, and nearly all of them have been very sharp as well. I know both of Larry Ellison's kids socially through the movie business...and they're both quite bright. Another friend is a super-smart documentary maker/anthropologist. Her dad was a hugely influential anthropologist/cyberneticist/UC regent and her grandfather was the biologist who popularized Mendel's work and coined the term "genetics." So while there was some falloff between generations, it was hardly 160/120/114.

Anonymous said...

Obviously, there are certain sub cultures in the USA where wealthy fathers are able to successfully require their sons to marry when the young man is young. These wealthy fathers are also able to motivate their sons to marry young females with very high IQ. None of this is theoretical. Look at the high genetic IQ of the females that Mitt Romney's sons married, just as an example Or look at the women that the sons of Indian Brahmins marry in the USA. Young men just lack the judgement to select their own wives. It is that simple. The fathers of those young men should be selecting the wives of their sons. I am very interested in hearing about other groups in America in which wealthy men are able to insure that their sons marry females with genetically high IQ.

misty said...

"Now, when you think of these groups, does "great personality for a wife" come to mind?

I am not being sarcastic.

Honest question."

Convert to Mormonism. I hear Marie Osmond has a genius daughter who looks just like her ma.

JSM said...

"Nope, there is not "plenty" of them. The intersection of the sets "very young" + "fertile female" + "150 plus IQ" is going to be extremely small. Only one person in approx 2,300 has an IQ greater then or equal to 150.

The good news is that both the importance of IQ and its hereditary nature are both wildly overrated around these parts. Extremely intelligent people are commonly born to not-very-intelligent parents. And people with IQ's much less than 150 commonly do very well for themselves in America."

The funny thing here is, while countering the silly notion that fertile, IQ-150 women are common, he asserts an even sillier notion:

That extremely intelligent people are "commonly" born to not-very-intelligent parents.

Uh, no, they're not. Extremely intelligent people are virtually never born to not-very-intelligent parents.

I daresay there are far more, numerically, 150-IQ fertile females than geniuses born to simpletons.

Anonymous said...

+ one on the Marie Osmond thing

Anonymous said...

" Donald Trump and Hilary Clinton encouraged their daughters to find Jewish men to marry?"

If true, they set their daughters a more difficult task than necessary. Unz has shown that there are far more whites capable of Harvard level work than Asians and Jews combined. With the parents' assistence there would be no lack of "connections" even for a white boy from the sticks.

Robert Hume

Anonymous said...

In reply to Robert Hume, you are correct in that Trump and Clinton could have found high IQ non asheknazi husbands for their daughters. But the best evidence is that non ashkenazi whites in the USA revert to a totally different mean IQ than askenazi do. Therefore with Trump and Clinton focused on the IQ of their GRANDCHILDREN, a high IQ ashkenazi son in law may make more sense than a high IQ white son in law. Do the math

Anonymous said...

I think both boys were the sons of Askenazi White collar criminals so great match I guess... espescially in the case of Clinton.

In Ivanka Trump's case, the father-in-law white collar criminal is a billionaire whose wealth is on a more solid footing than her father's. I wouldn't shed too many tears for her over not snagging Tom Brady.

E. Rekshun said...

In my early 30s, I had a couple of dates w/ a very attractive White woman my age from Jamaica. At least she looked (mostly) White, but I suspect maybe not. Neither she nor I had children. The few dates did not lead to anything further, but after she learned about my Mensa membership and obvious good health, she offered me the opportunity to impregnate her, no strings attached. I declined the offer.

Anonymous said...

"Uh, no, they're not. Extremely intelligent people are virtually never born to not-very-intelligent parents."

Steve's correspondent mentioned that Newton's father was an illiterate farmer. This is true. Carl Friedrich Gauss's parents were working class people, and his mother was illiterate. Michael Faraday's parents were poor. The Wikipedia mentions his father having been an apprentice to a village blacksmith.

Bill Clinton's mother was a nurse and what I'm going to call here a loose woman. I think I've read that her parents picked cotton for a living. The guy who ended up on Bill Clinton's birth certificate was a traveling salesman, a son of poor farmers. John Lennon's parents were irresponsible, lower-class people. It's not typical for very smart people to be first-generation descendants of riff-raff, but it happens.


David said...

We're either getting inevitably stupider (regression to the mean) or getting inevitably (?) smarter (Flynn Effect). Or maybe we don't know what is really happening. My advice: put a baby in the woman you like (if she consents, of course) and fuggedaboutit.

Dan Kurt said...

I don't think that the analysis is correct for three reasons.

!) No one here (over an extended time of watching) appears to have read and digested the Volkmar Weiss papers. Google "The IQ-Trapper"

2) In my university life I became acquainted with student while I was at an Ivy League Graduate School. He had an IQ North of 160. His Graduate Record scores were 800 verbal, 800 math, and 960 of 970 in Chemistry. He, BTW, never studied. He married a Graduate Student who got a Ph.D. in 3 years in a hard science. I don't know her IQ but she exuded brains. Her father was a Wall Street Banker and her mother had risen through the New York Public School System from teacher to district supervisor. The really smart student and the girl he married had only one child. Their son is now in his mid 30s. That boy is some kind of math wonder. When the boy was looking for a graduate school he was invited for interviews at Berkeley, Stanford, UCLA, Cal Tech and accepted a fellowship at a top 20 in the world university. He of course now has a Ph.D. and works for a defense contractor but he had been a University Professor and research scientist. I don't know what his IQ is but I did learn that he got his Ph.D. passing all of the exams (especially the comprehensives) the first time, a rare feat at a top American University. His IQ must be also really high.

Here two really, really smart parents had one child and he is really, really smart. Not much descending toward the mean that I can see here.

3) When I was in Grade School and High School I encountered an individual who came from a family where neither parent had attended college. He had a sister who was much younger than he was. The mother was a house wife and she was my Den Mother when I was in cub scouting. The father was my Assistant Scout Master. They were normal people. The father was a small business man.

Their son and daughter both became academics. The boy won a scholarship to an Ivy League college and eventually got a doctorate. The girl also got a doctorate and also became a professor. Where did these TWO out of TWO very bright children come from?

Read Volkmar Weiss. I think his take on the genetics of intelligence makes more sense than the standard model.

Dan Kurt

Kevin C. said...

"Were society in general to grant the status and appreciation to mothers in general that the Mormon Church does to its women, the ensuing baby boom by the smart women would knock yer socks off."

There are other groups that do encourage motherhood- Orthodox Christian and Jewish groups; Catholics encourage it in a roundabout way- no birth control.

And despite the liberal meme that kids from religious families are screwed up, the reality is that they are more likely than average to have a decent, healthy normal life without succumbing to life with liberal vices- drug abuse, VDs, crime, etc.

You want your kids to grow up normal in a traditional sense- healthy, own their own home, decent job, with 2+ kids, and a family dog, take them regularly to church.

Anonymous said...

"The guy who ended up on Bill Clinton's birth certificate was a traveling salesman, a son of poor farmers." I read Bill's real father was a local doctor that his mother was having an affair with.

Anonymous said...

"At least she looked (mostly) White, but I suspect maybe not." A black friend of mine from Jamaica says that all "white" Jamaicans are at least a little black.

Anonymous said...

Considering the majority of the Romney sons needed IVF to produce grandchildren for the clan, the Darwinian robustness of the wives chosen is questionable, whether they have high IQs or not.

Anonymous said...

"Look at the high genetic IQ of the females that Mitt Romney's sons married." George Sr. failed Jeb, but maybe George P. married well (but no kids so far.)

polymathblogger said...

It's ridiculous to expect kids whose parents, grandparents, and great-grandparents were all smart or brilliant to regress to anything close to 100. Also, all regression to the mean happens in the first generation -- if someone's parents were 160 IQ and he and his siblings are all around 150 it is safe to assume that no more regression will occur and that the 150 will "breed true" (of course they should be looking for "good breeding" in their mates and not just for smarties).

It's also true, though, that population size matters and large populations will have very high IQ people even without much assortative mating. Thus proles can feel justifiable pride when their ethnic group produces a genius, because they contributed to making N larger.

Anonymous said...

"Were society in general to grant the status and appreciation to mothers in general that the Mormon Church does to its women, the ensuing baby boom by the smart women would knock yer socks off."

Yeh, but the media control the message, and have you looked at the media lately?

Gay men and dullards (and gay dullards too). These people are not those that grant motherhood high status.

Anonymous said...

"Considering the majority of the Romney sons needed IVF to produce grandchildren for the clan, the Darwinian robustness of the wives chosen is questionable, whether they have high IQs or not.'
_________________________________

And you know this how?

Jokah Macpherson said...

it assumes multi-generational saintly resistance to blonde bimbo's charms

In the cast of most super-high iq people it would probably be the other way around.

Cail Corishev said...

According to those odds, my parents must have won the lottery. They had four kids, all top of their class. I don't know the others' IQs, but mine was tested at 160, and I doubt any of the others are below 120 (I'd guess 145, 140, and 120). Our folks are smart, but not outrageously so, which means they managed to have four kids that probably average higher than them. Pretty long odds.

Assistant Village Idiot said...

The core assumption on regression to the mean here is that real life is going to follow rolls of the dice. Just because a distribution is standard does not mean that it is random.

Some data on what the High-IQ's of actual couples and their children are might be a better place to start. Empiricism should start us off here, not theory.

There is another odd overlook here. The idea that one would have to have 434 kids to get one over 160 (even if that's true, which I doubt, see above), and that this is a ridiculously high number, results from thinking about childbirth and family size, not numbers. 1 out of 434? In the general population it's 1 out of 30,000! If you look at such 160/160 pairings as an aggregate, 1 out of 434 is pretty good.

BTW estimated individual IQs in my troupe here. Parents 160/150. Children 150/137. Not such an enormous regression there.

Anonymous said...

Extremely intelligent people are virtually never born to not-very-intelligent parents.


That allegation is simply false. And it is based on a number of faulty assumptions. The most obvious faulty assumption is that the genes which govern intelligence are never recessive.

It's like saying "People with blue eyes are virtually never born to parents who do not themselves have blue eyes". That statement is categorically and scientifically false. The genes governing eye color are well understood. You can see a breakdown of the probabilities involved here.

The genes controlling intelligence have still not been mapped but there are almost certainly a lot more of them than those for something as simple as eye color. The Punnett Square would be very large and complicated. But these is no reason to believe that the principles of genetics which apply to other traits do not apply to intelligence.

As somebody else has pointed out, there are plenty of examples of very intelligent people who were born to parents who themselves never displayed any signs of genius. The data fits with the theory - intelligent people are commonly born to not-so-intelligent parents.

Veracitor said...

Mixed-race children often exhibit "hybrid vigor" but often don't exhibit special traits-- desirable or undesirable-- which stem from genes more likely to be reinforced if both parents are more likely to carry them. For example, if both parents are drawn from some moderately-inbreeding population P famous for, say, musical talent, the kids are more likely to exhibit that talent, as well as more likely to exhibit any other popular traits from their ancestral population like, say, high blood pressure. If only one parent is drawn from population P and the other parent from some (genetically) distant population Q, the likelihood of reinforcement of both advantageous genes and disadvantageous genes is diminished. A commonly observed effect is that the diminution of disadvantages leaves the offspring healthy and energetic, but the diminution of rare talents may disappoint parents who might have hoped their offspring would "follow in their footsteps" to become circus acrobats or something.

To the extent (Ashkenazic Gaucher's syndrome, anyone?) that rare genes in some population P boost IQ, outbreeding is likely to reduce their prevalence and influence, so very smart parents who want very smart children may have to trade off the likelihood of other genetic disadvantages related to inbreeding to get them. Eventually "preimplantation genetic therapy" may let artifice overcome statistical variation.

As someone else pointed out, the rule of thumb if you want smart kids is: marry a smart spouse from a smart family, as smart as you can get while fulfilling other criteria such as health and personality match. It's an "optimization problem;" good luck!

Anonymous said...

the best evidence is that non ashkenazi whites in the USA revert to a totally different mean IQ than askenazi do.


Even setting aside the fact that comparing "ashkenazi" to "non ashkenazi whites" is a logically fallacious exercise, the best evidence is still pretty shaky as regards your claim.

Anonymous said...

I get the sense that many of the men on this thread do not think they have what it takes to persuade their soms to marry females with high iqs

Anonymous said...

Of course, encouraging the intelligent to reproduce helps the breeders equation to kick in ... as does selection and downward mobility flushes bad alleles out of the population.

Anonymous said...

if both parents are drawn from some moderately-inbreeding population P famous for, say, musical talent, the kids are more likely to exhibit that talent


Perhaps. It's unproven, but lets assume for the moment that you are correct. The reality remains that immense numbers of musically talented people are born to parents who themselves never displayed musical talent. I suspect this is the case for the majority of major musical figures in the 20th century.

Anonymous said...

"The data fits with the theory - intelligent people are commonly born to not-so-intelligent parents."

But only within certain groups. White, Jewish, northeast Asian, some Indian 90 to 100 IQ people have a potential to produce geniuses, but black, Amerindian, etc. 90 10 100 IQ people do not seem to have that potential. Someone here already mentioned this, and it's very important: when dull and average people display pride over the the achievements of their super-smart co-ethnics, they're justified in doing this. It's not entirely a self-serving fantasy.

Similarly, slow blacks can become parents (or grandparents) of world champion sprinters, but slow whites cannot. In a way, slow, overweight blacks are justified in being proud of Usain Bolt.

JSM said...

"Steve's correspondent mentioned that Newton's father was an illiterate farmer. This is true. Carl Friedrich Gauss's parents were working class people, and his mother was illiterate. Michael Faraday's parents were poor. The Wikipedia mentions his father having been an apprentice to a village blacksmith."

Newton: Illiterate =/= unintelligent, if the opportunity to learn to read was never encountered. Only in an era of universal primary education does inability to read correlate strongly with problem solving ability.

Working class =/= unintelligent.

Poor =/= unintelligent. Catholic priests in the Middle Ages were some of the most intellectually adept, and took an oath of poverty.

Oh- and the blacksmith back when horses were the main power source, was hardly the poorest guy in the village.

Anonymous said...

Only one person in approx 2,300 has an IQ greater then or equal to 150.

Hint. High IQ people know how to spell than.

Anonymous said...

My own parents were a housewife and a farmer. Neither ever displayed any great intelligence. But they had five children, three of whom I know for a fact have IQ's in the 140 range. The other two both have college degree's (in engineering and IT) but I don't know their IQ for certain.

I could make up a very long list of famously intelligent people whose parents were distinctly unremarkable,

David said...

>The girl also got a doctorate and also became a professor.<

In the humanities, education today tends to be mere credentialing in exchange for exorbitant tuition. This girl is bright if her field is chemistry, physics, or the like. But I know a few gals with a Masters in Education or Psychology working on a Ph.d, as well as one w/ a Ph.d... they haven't read a darn thing in their fields except their teachers' texts and handouts. One psyche "master" never heard of Freud (despite Dr. Fraud's dubious value, he is a founding father of modern psychology and had crucial insights).

(Do read the article I linked to above. It's very good.)

Anonymous said...

Hint: High IQ people contribute something more intellectual to the discussion than spell checking other people's comments.

David said...

>immense numbers of musically talented people are born to parents who themselves never displayed musical talent. I suspect this is the case for the majority of major musical figures in the 20th century.<

One of the favorite set pieces of classical pianist Alfred Brendel, which he told always with cheeky glee, contradicted the usual musician bio: "My parents were not musical.... We were not Jewish, to my knowledge.... There was no music in the home...."

Steve Sailer said...

"It's ridiculous to expect kids whose parents, grandparents, and great-grandparents were all smart or brilliant to regress to anything close to 100."

Is it?

I've been interested in this for a long time, and I'm always on the lookout for references to multigenerational distinguished families. But I end up citing the same ones over and over: Darwins, Huxleys, Waughs-Cockburns, Eliots, maybe Huntingtons. Bachs in music. It's a real phenomenon (whatever the balance of nature and nurture is in these examples), but it's not an overwhelmingly common one.

Anonymous said...

I believe it has been proven that in the USA, verbal IQ correlates to financial success much more than mathematical IQ. I believe it has also been proven that ashkenazi men average 114 verbal IQ and white men average 100 verbal IQ. It should not surprise anyone that in a pure meritocracy the average son of the average ashkenazi will out perform the average son of the average white

Steve Sailer said...

"Some data on what the High-IQ's of actual couples and their children are might be a better place to start."

There are several thousand children of the NLSY-79 cohort who have been tested.

Anonymous said...

To expand on this:

Real-world evidence suggests that 90 IQ whites and Asians have some potential of becoming parents or grandparents of 160 IQ people, but that 120 IQ blacks do not. Blacks admitted to top universities tend to go into politics, lawyering, etc., not into science or engineering. I'm not aware of any even part-black certifiable geniuses in any field. Yet there are definitely some 120-130 IQ more-than-half-black people out there.

Similarly, the Chinese or the Russian 100 m dash record holder probably has no possibility of fathering a world record holder or a world champion in the 100 m dash. But a physically slow, unathletic black person has that potential. It simply cannot be true that ALL athletic blacks are children of other athletic blacks, though most undoubtedly are.

Anonymous said...

Steve, you forgot the Bernoullis.

Anonymous said...

Anonymous 1/27/13, 5:51 PM,

The dichotomy is between verbal IQ and visuo-spatial IQ. Both contribute to mathematical ability to some degree. There has been plenty of Ashkenazi mathematical talent.

Anonymous said...

I believe it has been proven that in the USA, verbal IQ correlates to financial success much more than mathematical IQ. I believe it has also been proven that ashkenazi men average 114 verbal IQ and white men average 100 verbal IQ.


Then you believe wrongly. (1) Neither of these things has ever been proven. (2) Richard Lynn calculated* the verbal IQ of American Jews as 107. This does not "prove" that the verbal IQ of American Jews is 107, but it does undermine the notion that their verbal IQ is 114.

*Calculated here means that he looked at the various studies which have been done, all of which have their flaws, and made his own estimate based on them.

Anonymous said...

I don't have much to add other than...

Genes jump around. Recessives jump generations, but just because a child appears 'average' doesn't mean they don't carry the DNA to create excellence.

Eventually that recessive gene will find a match somewhere down the line. And that's all that matters.

If you marry based upon love, and commonality...probability says that you guys share a lot of recessives hence why you get along so well.


Just don't do something totally stupid and marry out of your race so the recessives can't find a match.

Furthermore, why are Farmers and housewives not considered high IQ to you guys?

Running a successful farm is pretty equivalent to running a successful business.

Cail Corishev said...

"Extremely intelligent people are virtually never born to not-very-intelligent parents."

"Extremely intelligent people are commonly born to not-very-intelligent parents."


The truth of both statements depends entirely on the meanings of "commonly" and "virtually never." How often do two parents of average IQ produce a Charlotte Simmons type who's clearly at least a couple of deviations above them? One in a hundred? In a thousand? More? Is it more common than, say, two people of average height producing a 6'8" kid with NBA potential? If not, then "virtually never" doesn't seem too far off the mark.

biologist said...

The population mean parameter won't budge in the wealthy scion scenario unless all of the wealthy families do the same thing AND breed only with one another.

Otherwise, with each generation, you're out-breeding your advantage.

"It's ridiculous to expect kids whose parents, grandparents, and great-grandparents were all smart or brilliant to regress to anything close to 100."

Okay, but how long can you keep that selection going?

Once you start breeding your genius families, they have to only breed with other genius families. So the selection of the mates has to be not only his/her IQ but grandparental IQ as well.

As was pointed out, most smart people do not come from such families, so it's really hard to keep it going.

DoJ said...

polymathblogger is correct. Steve's correspondent is doing the math wrong: regression to the mean is not as severe as he thinks. I'll try to explain here.

Measured IQ can be crudely decomposed into two components: genotypic expectation, and everything else. ("Everything else" includes a wide variety of factors ranging from nonlinear genetic interactions--"epistasis"--to environmental quirks, testing error, and random chance.)

"Narrow-sense heritability of 0.64" means that 64% of observed variance in IQ scores can be explained by differences in genotypic expectation, and the other 36% is explained by everything else. Mathematically, this is modeled by a sum of two independent normally-distributed values, where the first has a variance of sqrt(0.64), and the second has a variance of sqrt(0.36). (Hopefully it's clear now why I changed "0.6" to "0.64" in this exposition.) The sum then has variance 1.

With a bit of calculus, you can determine that the average person with a +4 SD IQ score has a +3.2 SD genotypic expectation and is +2.4 SD on "everything else". If they marry another +3.2/+2.4 person, then their kids will be scattered around +3.2/+0, which corresponds to a +2.56 SD IQ. So far, this is consistent with what Steve's correspondent has said.

But this is where the "regression" slows down or stops. The typical +2.56 SD IQ kid does not have +3.2 SD genotypic expectation and +0 SD "luck"; instead they're around +2.048/+1.536. The latter folks' kids will exhibit full regression to the mean, but our +3.2/+0 protagonist's will not. Especially if they marry carefully.

JayMan said...

"Many nerdy or high achieving men bent on reproducing are troubled by the fact that most intelligent women want a career and likely do not want to have children (or want to adopt orphan baby at age 50, once they have “made it”). Women who are slightly less intelligent may want to have families and even to have bigger families."

Yup, that's the truth. In general, it seems that most dysgenic fertility stems from low-IQ women. Male fertility appears to not be significantly affected by IQ:

It’s not the cads, it’s the tramps « JayMan's Blog

DoJ said...

"where the first has a variance of sqrt(0.64), and the second has a variance of sqrt(0.36)."

Correction: this should say "where the first has a standard deviation of sqrt(0.64), and the second has a standard deviation of sqrt(0.36)."

Veracitor said...

" I'm not aware of any even part-black certifiable geniuses in any field."

I can't say he's a "certifiable genius" but isn't Obama's half-brother a physicist or something similarly non-slouchy?

As for musical talent in inbreeding populations I give you Eastern European Gypsies; I believe Steve has treated their case before.

jody said...

if regression to the mean were this severe, there would be no such thing as the very entrenched "social classes by intelligence" phenomenon we see having emerged in western society over the last hundred years.

the math set out here in this post essentially posits random churning of the population. it suggests the smart people today, won't stay on top for more than a generation, and the dumb people today, will randomly be producing some of the leaders of tomorrow. every new generation, it will be a random scramble for control of the top of society.

this isn't what we observe at all. in fact we observe the opposite. the people at the top are becoming entrenched due to selective sorting and mating.

no way on earth are smart couples having almost all of their kids turn out 2 SDs less intelligent or whatever preposterous result this regression to the mean math suggests. i never saw that, ever. janitors kids and professors kids DO NOT converge on IQs. that's just retarded.

i used to advise student athletes in high school, and NO WAY were dumb parents randomly turning out ivy league quality teenagers, and smart parents turning out community college level teenagers. exactly the opposite. both your parents were ivy leaguers? then you probably applied to and got accepted to that quality of university too. both of your parents barely made it through high school? then one of the satellite campuses of state U was probably the best you could do.

what this math says is that every generation, the smart people will have much dumber kids, and the dumbest people will have much smarter kids, and then there will be a mad max cage war where they meet in the middle and duke it out for control of society all over again. this absolutely, positively does not happen.

in 2013, the dumb people have dumb kids, and they mostly stay at the bottom of society. the smart people have smart kids, and they usually take over for the outgoing, aging generation of smart people.

probably the only thing which is accurate is that wild outliers are random flukes. no family averages 7 feet in height generation after generation, and you could never expect to make 7 foot tall kids. but you might average way over 6 feet tall for centuries.

misty said...

I know this is a statistics oriented blog but I can't help wondering if your elusive dynasty of geniuses wouldn't be easier to found if you were to focus on brain features rather than raw numbers. It's been awhile since I've done any reading so the only two things that come to mind are eidetic memory and mathematical ability.

Couldn't you start talking in terms of probability of inheriting certain abilities that don't necessarily get a person into a genius range of IQ but that are atypical and demonstrable. In practice, this might mean that an engineer or doctor who marries a female who teaches hs math is guaranteeing a foundation of a brain with certain proclivities/features in most of the offspring. Different strengths guaranteed if a lawyer marries an English teacher; an architect marries an art teacher, etc. Mating with someone outside the skill set could add abilities or cancel them out and explain your quality control issues. LOL

Sorry, I'm always going to like my approach better than yours. Statistics require a leap of faith I'm never going to make.

Anonymous said...

How often do two parents of average IQ produce a Charlotte Simmons type who's clearly at least a couple of deviations above them? One in a hundred? In a thousand? More? Is it more common than, say, two people of average height producing a 6'8" kid with NBA potential?


It's obviously much more common that that. What world do some of you people live in?

Truth said...

"Real-world evidence suggests that 90 IQ whites and Asians have some potential of becoming parents or grandparents of 160 IQ people, but that 120 IQ blacks do not. Blacks admitted to top universities tend to go into politics, lawyering, etc., not into science or engineering. I'm not aware of any even part-black certifiable geniuses in any field."

LOL; I think this "evidence" demands a committee review.

Let me let you in on a secret; very few black people want to make their living in fields that do not allow for social interaction. This is totally independent of IQ, from what I've experienced.

I know very few black scientists/engineers, but a fair number who have earned their degrees in these fields, even amongst those who stay in the field, they tend to go the Tyson De Grasse route, and deviate toward some sort of a sales/marketing/spokesperson route.

Truth said...

""Which mean are we regressing to? Usually it is the taken to be the population in general but it has to be the mean of your ancestors. There's no way non-ancestors can affect your IQ, right?"

The whole, entire summation of HBD is that all white people are your ancestors.

Anonymous said...

i used to advise student athletes in high school, and NO WAY were dumb parents randomly turning out ivy league quality teenagers, and smart parents turning out community college level teenagers.


1) Your views on intelligence would carry more weight if you ever learned how to write normal English sentences, with capitalization and stuff.

2) Your test pool of so-called "student athletes" tells us a big fat nothing about anything related to intelligence, other than the banal fact that US colleges go to great pains to enroll a lot of blacks.

Luke Lea said...

"It's not typical for very smart people to be first-generation descendants of riff-raff, but it happens."

You could throw in Lincoln and Alexander Hamilton to that list. Shakespeare too I suppose.

Truth said...

" If you find a woman who thinks white people stealing black babies is wrong, or immigration is white genocide, or that miscegenation is a sin. You should wife that bitch up"

That's it, gentlemen, you've just been handed the three questions that practically guarantee you a fruitful and successful marriage.

Thagomizer said...

The numbers in this post seem inflated. A 120 IQ is typical of an MD or University Professor. It's unusually high for a high school teacher.

http://www.iqcomparisonsite.com/occupations.aspx

http://anepigone.blogspot.ca/2011/01/average-iq-by-occupation.html

misty said...

"One psyche "master" never heard of Freud (despite Dr. Fraud's dubious value, he is a founding father of modern psychology and had crucial insights)."

Name 2.

Freud, like Darwin, isn't easy to digest. Just as most biology majors haven read The Origin of Species, most psychology majors have no reason to read Interpretation of Dreams. These people simply don't know the source of many of the theories they utilize in their respective disciplines. Your Psych grad student no doubt could've discussed emotion and motivation as well as defense mechanisms adroitly enough though not readily connected the dots back to Freud. Further, some of what we believe originated w/ Freud because of his fame actually may have begun with proponents of psychoanalysis who have mostly been forgotten.

The ability to analyze such seminal works and provide a synopsis isn't developed in our education system with its preference for textbooks. Doing so except on a lark is probably counterproductive anyway since behaviorism and statistics are much more essential to the field. Now, your psych grad student who doesn't know much about statistics has no doubt specialized in some form of therapy and isn't interested in trotting out their own version of The History of Psychology or engaging in statistical analysis.

You know the field is pretty competitive. A grad student at the caliber of Uni you would attend will be the cream of the crop one way or another.

Steve Sailer said...

Generally, the most famous people in history are sons of somebody who was rising in the world (often enough to set some money aside for his son's education or career).

Winston Churchill modeled himself after his distant ancestor John Churchill, first Duke of Marlborough, but even with all the advantages (e.g., owning Blenheim Palace), the subsequent Marlboroughs were pretty mediocre until Winston's grandfather married a hard-charging lady. Her son Randolph made it to Chancellor of the Exchequer, and Randolph married Jenny Jerome, the celebrated daughter of a self-made NY millionaire. Winston's son Randolph was a talented guy, but nobody liked him except Evelyn Waugh (which probably tells you something there). And with all the advantages of the most famous name in English history, subsequent Churchills have mostly just been worthy fellows.

This is a pretty common pattern of rise and fall in eminence across, say, three to five generations.

Anonymous said...

in 2013, the dumb people have dumb kids, and they mostly stay at the bottom of society. the smart people have smart kids, and they usually take over for the outgoing, aging generation of smart people.


No, that's not actually the case. Stop allowing your obsession with blacks to spill over and pollute all your thought processes. There have been many posts right here on this site discussing how the people at the top of our society exclude high IQ but low status white people from displacing them.

Anonymous said...

Generally, the most famous people in history are sons of somebody who was rising in the world (often enough to set some money aside for his son's education or career).



Hitler? Stalin? Thatcher? Reagan? Obama? But that's politics. You want to talk technology? Let's look at aerospace, which your dad worked in. Donald Douglas, the founder of Douglas Aircraft Company? Or Leroy Grumman? The Wright brothers?

Anonymous said...

Why do men equate Madonna, Angelina Jolie and Charlize Theron with High IQ?

Madonna reportedly has an IQ of 140.

Anonymous said...

"I've been interested in this for a long time, and I'm always on the lookout for references to multigenerational distinguished families. But I end up citing the same ones over and over: Darwins, Huxleys, Waughs-Cockburns, Eliots, maybe Huntingtons. Bachs in music. It's a real phenomenon (whatever the balance of nature and nurture is in these examples), but it's not an overwhelmingly common one."

The Dysons. The Batesons. The Marsalis and Brubecks in jazz.

The Barrymores and Richardson/Redgraves in acting, if you consider that a form of accomplishment.

Marie Curie's children, granddaughter, and great-grandson were or are all distinguished chemists, physicists, and astrophysicists.

And there are several physicists named Bohr descended from Nobelist Aage, who himself is descended from Nobelist Neils, who himself is descended from a brilliant physiology professor...


Steve Sailer said...

When I checked in 2000, six hard science Nobelists were children of other Nobelists. Is that a big number or a small number?

Steve Sailer said...

In Charles Murray's Human Accomplishment, he lists 240 "giants" in Western arts and sciences. Eleven of the 240 surnames are listed with an initial to distinguish them from others with the same surname in his list of 4000 "eminent" figures (e.g., P. Curie and M. Curie, or Jak. Bernoulli). The husband-wife Curies are the only giants who share a surname.

International Jew said...

What are the pros and cons of having your children raised by your 115 IQ stay-at-home wife, versus raised by the 90-IQ nanny hired by your 140-IQ 60-hour-a-week lawyer wife?

Anonymous said...

"I've been interested in this for a long time, and I'm always on the lookout for references to multigenerational distinguished families. But I end up citing the same ones over and over: Darwins, Huxleys, Waughs-Cockburns, Eliots, maybe Huntingtons. Bachs in music. It's a real phenomenon (whatever the balance of nature and nurture is in these examples), but it's not an overwhelmingly common one."

One should remember that fame != IQ or even prominence within a field. How many people would know anything about Bill Gates Sr (a successful attorney) if not for his son? Perhaps he was even similarly smart, but did not direct his energies in a direction that was going to make him filthy rich. Similarly, Warren Buffet's father Howard was a four time congressman, but you would only really know who he is if you were a gold bug.

There are probably loads of examples like this, where high IQ extends back several generations but fame was only achieved by one generation. Another thing with the wealthy is that fame is as much a bug as a feature. Wealth attracts parasites and criminals. It's better not to be a target if you have a choice. Old money don't make the same mistakes as the nouveau riche. Did the Rothschilds suddenly lose their money? No, but we only hear about a couple of generations of them.

Anonymous said...

Another thing to consider is that low hanging fruit gets picked. Someone like an Einstein probably wouldn't push his kids into physics because it's too expensive and difficult to discover anything of note by yourself. Similarly, the Wright brothers got their start when a bicycle maker could build an airplane. It wasn't much of an airplane, but they got huge credit for it. A Burt Rutan has done far more interesting things and Boeing has built far more sophisticated airplanes using huge teams, but the Wrights have the name recognition.

The son of a Wright or an Einstein might decide he wants to make money instead of being famous, and the son of a plutocrat might decide he wants to make his mark as a Rabbi. Or maybe he gets sucked into World of Warcraft and is the head of the number one clan in the world, but otherwise has no distinguishing accomplishment. These things are hard to predict.

Another musical family - the Jarres. Father composed the music for Lawrence of Arabia, son composed seminal electronic music such as Oxygene, and holds records for the largest outdoor concerts in the world.

Another thing to consider is that sometimes it takes a while for your work to be recognized. Many artists only achieve fame posthumously. Mendel's work in genetics took at least 40 years to be recognized.

Anonymous said...

...very few black people want to make their living in fields that do not allow for social interaction.

A high percentage of very smart people are bored by socializing.

Anonymous said...

"What are the pros and cons of having your children raised by your 115 IQ stay-at-home wife, versus raised by the 90-IQ nanny hired by your 140-IQ 60-hour-a-week lawyer wife?"

For thousands of years the children of the aristocracy were breastfed and raised by prole nannies. This has been going on since Roman times. If this practice had a negative effect, folk wisdom would have turned against it and the rich would have stopped doing this many centuries ago.

Anonymous said...

Still yet another thing to consider in comparing generations of families is the explosion in college attendance as discussed in The Bell Curve, as well as the trend for near everyone above a certain IQ to attend college. In previous generations there were similar proportions of smart people relative to their peers, but they generally didn't go to university. There are still some high IQ who don't go to university.

This idea of reversion to mean is something I haven't seen a lot of in my own life. I can't think of one example of a smart person I know who did not have a smart parent, grandparent or some other ancestor who was not intellectually distinguished in some way.

Dan Kurt said...

re: "This girl is bright if her field is chemistry, physics, or the like. " DAVID

This girl was really bright and was a medical doctor who became an academic. Her professorship was at a medical school where she was a professor of Internal Medicine. She ran the internship and residency program in internal medicine at the medical school as well as the internal medicine clinics at the medical school hospitals. She also was involved in the Internal Medicine Boards. Her research was among other things the treatment of AIDS and she ran an AIDS clinic as well. She had to retire early because of health reasons which were related to intractable asthma according to my mother who always kept in touch.

I agree that many Ph.D. programs are soft.

Dan Kurt

Truth said...

"A high percentage of very smart people are bored by socializing. "

CEO's, corporate lawyers, high-level politicians, and high-ticket item salespeople, to name a few, are not very smart?

Anonymous said...

"Madonna reportedly has an IQ of 140."

She must be a genius. How else could someone reach the top of the music profession with,
a) a lousy voice
b) no music reading skills
c) no music writing talents
d) an inability to play an instrument
?

It's like becoming a science Nobel without knowing how to do math. A neat trick, for sure.

misty said...

"For thousands of years the children of the aristocracy were breastfed and raised by prole nannies. This has been going on since Roman times. If this practice had a negative effect, folk wisdom would have turned against it and the rich would have stopped doing this many centuries ago."

Sounds like a guilty conscience to me albeit in the opposite direction of those who make The Hand that Rocks the Cradle -type films. I'd say parenting practices were so hazardous back in the day it was six of one half dozen of the other. Handing your child over to someone who may know more than you do about child development isn't such a bad idea. Otherwise you're just hoping the person you hire had some good role models for whatever conventional style of parenting she uses. This annoys me no end.



Anonymous said...

The parents of terry tao are not exceptional, but have produced 2is kids with 180+ iqs and one with an iq over 145. That is statistically near impossible.

Anonymous said...

If reversion towards the mean is correct, does that mean two 60-IQ parents will produce 80-IQ kids who'll produce 90 IQ kids ?

Steve Sailer said...

"If reversion towards the mean is correct, does that mean two 60-IQ parents will produce 80-IQ kids who'll produce 90 IQ kids?"

More or less.

Veracitor said...

Yes, reversion toward the mean does predict the children of dull parents will average less dull than their parents.

Furthermore, reversion toward the mean predicts that the parents of individual very smart children are duller, on the average, than those kids.

As a statistical concept, reversion runs "both ways."

JeremiahJohnbalaya said...

I can't think of one example of a smart person I know who did not have a smart parent, grandparent or some other ancestor who was not intellectually distinguished in some way.

I've been thinking about this all day, and I have to agree. In fact, the correlation b/n my close associates and their parents is even higher in my experience than stated here. On the other hand, this also got me thinking about "misattributed paternity"(***) and apparently it's not as high as I'd been led to believe. So, this exercise was not entirely meaningless.

(*** according to Wiki, also know as "paternity fraud". Ha!)

Veracitor said...

"This idea of reversion to mean is something I haven't seen a lot of in my own life. I can't think of one example of a smart person I know who did not have a smart parent, grandparent or some other ancestor who was not intellectually distinguished in some way."

You need to read up on reversion toward the mean. It works with large numbers and averages. It predicts, for example, that the mean IQ of children of given high-IQ parents will be closer to the population IQ mean than the mean of the parent's IQ's. It does not predict that all those kids will be duller than either of the parents. It would be no surprise if some of the kids were smarter than their parents. Other forces predict that smart parents are more likely than dull parents to produce smart kids, so it is no surprise that smart kids tend to have smart ancestors.

As others on this thread have noted, the problem with simple reversion formulae is that they assume random breeding which is not what we observe in real life... Assortative mating is more common. So we get into the question of just which population we should take the mean (and SD and so-forth) from to do our calculations.

DoJ said...

"The parents of terry tao are not exceptional, but have produced 2is kids with 180+ iqs and one with an iq over 145. That is statistically near impossible."

Actually it's not that implausible; there are necessarily some couples out there where both parents have high genotypic expectations but "bad luck" on non-heritable factors; they can consistently produce very smart kids, especially if they also happen to be unusually effective parents.

"'If reversion towards the mean is correct, does that mean two 60-IQ parents will produce 80-IQ kids who'll produce 90 IQ kids?'

More or less."

Er, no. Assuming 50% additive heritability,

* 80-IQ kids of 60-IQ parents who marry other 80-IQ kids of 60-IQ parents will have their own ~80-IQ kids. This is because 60-IQ parents are, on average, people with "80-IQ genetics" who got very unlucky.

* 80-IQ kids of 60-IQ parents who marry *randomly selected* 80-IQ kids will have offspring clustering around 85 IQ, because the typical 80-IQ kid has "90-IQ genetics" and got unlucky.

* For the same reason, two randomly selected 80-IQ kids who marry each other will have offspring clustering around 90 IQ.

Bottom line is, everyone's IQ is a combination of genetics and luck. To a first approximation, luck averages out after one generation. The typical high-IQ person has both better genetics than average and better luck than average. But if you marry someone whose family has a long track record of exceptional accomplishment, rather than someone who's a one-off success story, your partner probably has reliably exceptional genetics and you have little to fear from luck.

I personally don't like the social implications of this, which is part of why I look forward to a world where conventional "good breeding" is no longer very important.

Anonymous said...

"On the other hand, according to historians none of Newton’s paternal kinsfolk were able to even sign their names. "

they were probably not bullied like he was.
For being a dunce and not the current nerd refrain of being too smart. A reflection of the inversion of our times.

Anonymous said...

consider finding a slightly less intelligent woman who is willing to have a few kids.

Or better yet, find a really stupid woman and have a ton of kids.

Anonymous said...

"Many nerdy or high achieving men bent on reproducing are troubled by the fact that most intelligent women want a career and likely do not want to have children"

Is there data for this? A breakout for married intelligent women vs. those who remain single for whatever reason?

High IQ couples are likely to move far from family supports. This makes raising kids even more challenging -- no romantic weekend breaks while the kids stay with grandparents, no one to fill in when the nanny abruptly quits. Add some business travel and medical issues and things get very messy indeed.

Anonymous said...

Another thought--life is not easy for women with IQs >140. They are not likely to find peer groups outside of academic settings, much less in neighborhoods. Staying at home with small children (besides being professional suicide) is exhausting and can become very lonely without intellectual peers.

Anonymous said...

The worse the environment is, the more reversion to the mean happens. The better the environment is, the less reversion to the mean happens.

Environment would include breastfeeding, iodine, omega 3, other factors of nutrition and etc.

James B. Shearer said...

The simple calculations in the post are misleading because they are ignoring environment (I believe they are assuming an average environment for the children). If you can provide your children an environment which is one or two standard deviations above average you can expect to do considerably better.

This is also an alternate explanation for talented families, they are consistently providing a superior environment for their members. Or of course it can be both.

Anonyia said...

"The numbers in this post seem inflated. A 120 IQ is typical of an MD or University Professor. It's unusually high for a high school teacher."

I second that. My IQ is around 125, and I am in the process of becoming certified to teach high school. Let me be honest- most of my peers in this program are not as intelligent. Particularly in the verbal sense. They are incredibly inarticulate for future teachers.

Also a lot of people on this thread are throwing out IQs of 140-160 as typical amongst their families. Maybe iSteve readers are just disproportionately intelligent, but I still find the preponderance of those numbers hard to believe. Hell, I am lucky here in the deep South to meet someone with an IQ over 115 or so. I would guess most of my relatives are in the 105-110 range, with my own parents being slight outliers.

panjoomby said...

on average, only-children (OC's) & oldest children (hmm, OC's again!) regress slightly less to the mean - since they have a slightly higher mean IQ. correct?

candid_observer said...

The issue of regression to the mean in these contexts is quite fascinating, but certainly quite complicated.

I think that the general point is that regression to the mean, as it is usually applied in this context, depends on the fact that one knows essentially nothing about mating individuals other than their own IQs, and quite general facts about the population with respect to IQ. Insofar as one knows more, particularly about their ancestors, one can make more precise predictions.

Historically, the way to escape the dreaded regression to the mean was to marry only into families of prominence. That prominence would typically be based on a long line of successful ancestors and their genes.

I would suggest that the reason that there are so few cases of families that succeed at the highest level is mostly due to the inability to control the assortative mating process at the highest level. In no small part, that probably has to do with the scarcity of opportunities for such mating at these levels -- how many such families can there be, and how likely is it that the children of such families will be interested in mating only with those of such families?

Cail Corishev said...

It's obviously much more common that that. What world do some of you people live in?

I've met one person who was clearly 2+SD higher than her parents. The kind of person who nods knowingly at the bit early in the movie Real Genius:

Professor: Your parents seem nice...
Student: They're okay, it's just sometimes they have no idea what I'm talking about.
Professor: I'm sure about that.

So I'd guess the odds of that kind of "prodigy out of nowhere" are closer to .1% than 1%.

Of course, if you spend a lot of time around high-IQ people, you're going to meet more who fit the bill, just as, if you spend all your time around low-IQ people, you're going to meet none.

jody said...

"No, that's not actually the case."

actually, it is the case.

"Stop allowing your obsession with blacks to spill over and pollute all your thought processes."

where did i say anything about race in my long post?

my comments were based on within group observations of euro americans in about 5 US states over a 30 year period. it is very rare for two IQ 100 parents to produce an IQ 145 child and almost unheard of for them to produce an IQ 160 child. however, it is positively common for two IQ 145 parents to produce multiple children who are also in the IQ 145 range. in fact, from my personal observations, THAT WAS NORMAL.

i saw this over, and over, and over. many US public school districts have programs based specifically on this. they establish and maintain a seperate part time academic program for students with an IQ over a certain number. say, 130 or 145. however they want to set the bar, so the program has a good amount of separation from the mainstream academic program to justify it's existence, but not too high so that there's only 2 kids in it. they wouldn't set it at 160.

all students in the school district are given IQ tests when children and any who qualify are offered participation. it's not required - guys in my school district turned it down, or did the program for a few years, found it boring, then dropped out.

almost none of the kids in the program came from average parents. instead most of them came from smart parents. engineers, scientists, doctors, professors. if regression to the mean was as severe as the math in this post suggests, then the state college high school in pennsylvania would not usually have the most national merit scholars in PA every year. but it does, because that's where the penn state professors' kids go to school.

carmel high school, in carmel, indiana, wouldn't have the most national merit scholars in indiana, because all the smart people who move there would have dumber kids. except, they don't. they have smart kids. i know, because i worked there for a while.

even in my own family i can see that there is no regression to the mean. the average brainpower on my dad's side of the family remains in the IQ 130 range generation over generation. my mom's side of the family, who are white trash losers, stay firmly in the 100 range. she was an outlier. this is a persistent 2 SD difference over decades.

FWG said...

Steve, Six hard science Nobelists being sons of previous winners is a lot. From where I stand anyway.

Anonymous said...

Hmmm... could the desire for high IQ grandchildren be the reason both Donald Trump and Hilary Clinton encouraged their daughters to find Jewish men to marry?

Must be, couldnt be any other reason.

Anonymous said...

The parents of terry tao are not exceptional, but have produced 2is kids with 180+ iqs and one with an iq over 145. That is statistically near impossible."


Look, statistics just describe what has been observed. They don't determine what can be observed. They are useful for predicting trends. They are not applicable to outliers. Anyway, there is some rare biological event causing the situation you describe. It would be really interesting to get their DNA sequenced and see what the kids actually inherited. Like I tell my short son, while we have genes for tall, short and average stature, all that matters for him are the genes he actually got. So, what matters for these extra smart kids of just regular folks are the genes they actually got.

Anonymous said...

""If reversion towards the mean is correct, does that mean two 60-IQ parents will produce 80-IQ kids who'll produce 90 IQ kids?"

More or less."

This is why anecdotal arguments for defending mass immigration from the third world are specious. When large numbers of a low IQ ethnic group settle in the country, to be sure after a couple of generations you will start to see a few successful ones. Example: the Hmong are essentially a stone age people demonstrating little inclination to advance despite thousands of years of contact with more advanced cultures. Yet UC trots out the two or three token Hmong who attend UC Berkeley or UCLA and proclaim the entire ethnic group an American success story. And usually the students don't even appear to be full blooded.

jody said...

you see, one of the goals of modern american public education is specifically to FIND those diamonds in the rough. those missed, overlooked, untapped high IQ kids of the lower class and middle class, and get them into high powered academic programs and get them producing quality work as adults. NOT to leave them languishing in a coal mine or a mechanic's garage or a family supermarket somewhere.

but guess what? THEY DON'T EXIST in high numbers. we're looking for them and WE DON'T FIND THEM. we've been looking for them for 100 years. we've pretty much all found them. the population is pretty much sorted.

to give you an example you might understand, it's a lot like american idol. do you notice how american idol doesn't find any real, impressive talents anymore, like it used to, 9 or 10 seasons ago? that's because they went looking for obscure, missed, overlooked talents, and they FOUND THEM ALL. and now they're just going back and doing it every year and not finding much. because they found them all already.

this is why people who actually study this stuff with little political bias, know the united states is in deep long term trouble. because mestizos produce almost zero talented kids, in almost any field. and if i did want to make this topic about race, i'd point out how extremely unlikely it is that the great mexican wave which the US is experiencing today, is going to produce ANY geniuses. 40 million mestizos and probably, literally, ZERO geniuses will come out of it.

the regression to the mean math posited in this post, however, suggests that, given a level playing field, europeans will sort of struggle for control in a meritocracy with mestizos, because, well, their kids will almost always be 1 or 2 SDs dumber, putting them down in the range where the mestizos can credibly battle them for control of things.

that doesn't happen even in MEXICO, where the europeans are outnumbered by the mestizos and american indians 10 to 1. if it does happen in the US, it will be completely artificial. a result of affirmative action.

maybe we should look at south africa, where the europeans are also outnumbered 10 to 1, to see if average african parents actually do produce lots of kids in the IQ 130 range totally randomly, while the smart europeans in SA, the ones smarter than the average europeans in DA, are degenerating into IQ 100 slugs. oh wait, we don't need to check it out. we already can see that's not happening. with mariusz kloppers running BHP billiton, and elon musk running spacex and tesla. where are all the randomy IQ 145 africans and what are they doing? they don't exist, that's what.

Anonymous said...

If regression to the mean works as advertised then how can IQ ever have risen?

If we set the eugenic bar very low, if no one with an 60 IQ or lower was allowed to have kids wouldnt that gradually drag up the mean? That genes implicated in really low IQ just werent being propagated.

Anonymous said...

There seems to be glut of people commenting on iSteve claiming to have or know someone with a 160 IQ. That's a really rare number, essentially being the highest valid score on an IQ test. Additional talents like photographic memories and mental math abilities may accompany a super-genius IQ, but not necessarily.

I'd say after a life time in academia in a top ten school I've run across maybe three in my STEM career. Usually you can identify one by how quickly and precisely he talks and reasons.

Lion of the Blogosphere said...

This post is all wrong because people don't regress towards a general mean, they regress to the IQ of their grand parents and great-grand parents.

Anonymous said...

Bill Clinton's mother was a nurse and what I'm going to call here a loose woman. I think I've read that her parents picked cotton for a living. The guy who ended up on Bill Clinton's birth certificate was a traveling salesman, a son of poor farmers. John Lennon's parents were irresponsible, lower-class people. It's not typical for very smart people to be first-generation descendants of riff-raff, but it happens.

1) As Steve has reported several times here, it is all but certain Bill's biological father was a high-IQ local physician (not Blythe). It would be very interesting if any data could be found regarding the outcomes for this doctor's other children, legitimate or not. Bill's half-brother via his low-IQ mother was of course a lifelong f***-up.

2) I seriously doubt Bill had any eugenic design in orchestrating a Chelsea's marriage, since he almost certainly knows she isn't his biological child. Cf. the eventual bride of Prince Harry, who will almost certainly turn out to be less appropriate than Kate Middleton from a eugenic standpoint.

In any case, given that Chelsea and husband's co-habitation after their eight-figure wedding lasted about seven months, the question of the Clinton grandchildren's IQ is purely academic anyway.

Anonymous said...

*Calculated here means that he looked at the various studies which have been done, all of which have their flaws, and made his own estimate based on them

He Stevenjaygoulded it. For example to get a country having an IQ of 92 he took the results of 8 adults and 23 children. His results have therefore been kinseyed.

Anonymous said...

"It's not typical for very smart people to be first-generation descendants of riff-raff, but it happens."

You could throw in Lincoln and Alexander Hamilton to that list. Shakespeare too I suppose.


Shakespeare's father was a highly prosperous artisan, and a big wheel in local politics (at least until the religious tests were administered), so he was hardly riff-raff. From a Londoner's perspective a bumpkin perhaps, but not sleaze.

Hamilton's biological father likewise would not have been considered riff-raff by the standards of his time and place. Thomas Lincoln was rough and illiterate but not a scoundrel.

Anonymous said...

CEO's, corporate lawyers, high-level politicians, and high-ticket item salespeople, to name a few, are not very smart?


One group that doesn't below in the list above is corporate lawyers. With the exception of a few senior partners who are good at bringing in business, corporate lawyers are generally lousy at social interaction.

Anonymous said...

The parents of terry tao are not exceptional, but have produced 2is kids with 180+ iqs and one with an iq over 145. That is statistically near impossible.


It's not statistically near impossible, once you have a basic understanding of genetics and intelligence. (Something which is surprisingly lacking among the readers of this HBD blog)

This link will at least get you headed in the right direction.

Anonymous said...

Why do men equate Madonna, Angelina Jolie and Charlize Theron with High IQ?

Madonna reportedly has an IQ of 140


Just as Sharon Stone has an IQ of 154. Except that in real life she does not as it is fictional.

Beware IQ numbers from non administered tests.

Bill said...


Lion of the Blogosphere said...

This post is all wrong because people don't regress towards a general mean, they regress to the IQ of their grand parents and great-grand parents.

I always feel clueless when this particular topic come up. Can you suggest a link, article, or book which explains how regression to the mean in IQ works? Its hypothesized mechanisms, how the math works, and etc?

Anonymous said...

This post is all wrong because people don't regress towards a general mean, they regress to the IQ of their grand parents and great-grand parents.


No, they don't, they regress to the general mean. Of course the mean of your 8 great-grandparents is going to be close to the population mean. (In multi-racial countries like the modern US, to the population mean of your racial group) And the mean of your 16 great-great-grandparents is going to be closer, that of your 32 great-great-great-grandparents closer still.

In other words, regression to the mean words backwards as will as forwards, and for the same reason. Go back ten generations or so and "your ancestors" make up a decent sized slice of the general population, so of course they are going to resemble the general population in all sorts of ways. And going forward in time the category "your descendants" will typically be pretty large, and thus will take on the characteristics of the larger population.

The Legendary Linda said...

Regression to the mean sounds counterintuitive to people because most people you recognize as smart are high achievers, and thus come from families bright enough to support and encourage them. These are not typical high IQ people, they are high IQ people from bright families. But there are plenty of high IQ people who come from dumb families, you just don't see them because they are underachievers so they don't appear smart. James Holmes has an IQ of 145 but came from a presumably non-smart family since he was an unwanted pregnancy. Chris Langan (IQ 195 on the Mega Test) comes from a low class background.

Anonymous said...

Shakespeare's father was a highly prosperous artisan


No, he wasn't. He was an artisan, but never a highly prosperous one.

Anonymous said...

If regression to the mean works as advertised then how can IQ ever have risen?


What makes you think IQ has risen? Or more to the point, what makes you think that intelligence has risen?

Anonymous said...

more and more, it appears that the most likely explanation for phenomena where conscious intervention might have played a role is that conscious intervention in fact, did play a role. this would include things such as the high representation of gays at yale or jews at harvard, jewish IQ, Jimmy the Greek's black athleticism, and of course, the unusual number of private school kids on the PhD track born to lesbian mothers.

Anonymous said...

my comments were based on within group observations of euro americans in about 5 US states over a 30 year period. it is very rare for two IQ 100 parents to produce an IQ 145 child and almost unheard of for them to produce an IQ 160 child.


I don't find your "observations" to be of any value. Among other problems, why am I supposed to believe that you not only know the IQ of large numbers of students (which is highly dubious in itself) but that you also administered IQ tests to all these students parents?!

I'd don't believe a word of it, jody. I'll bet the farm that what you are trying to say is "The children from wealthy backgrounds struck me as smart and the children from poor backgrounds struck me as not so smart".

Anonymous said...

I've met one person who was clearly 2+SD higher than her parents. The kind of person who nods knowingly at the bit early in the movie Real Genius:

Professor: Your parents seem nice...
Student: They're okay, it's just sometimes they have no idea what I'm talking about.
Professor: I'm sure about that.

So I'd guess the odds of that kind of "prodigy out of nowhere" are closer to .1% than 1%




If that's your idea of a logical deduction, I'd hold off on applying to Mensa.

We have the subjective speculation - "I think I've met one person who met the criteria in question - followed by a movie reference - after which you move on to QED!

Anonymous said...

"As others on this thread have noted, the problem with simple reversion formulae is that they assume random breeding which is not what we observe in real life... Assortative mating is more common. So we get into the question of just which population we should take the mean (and SD and so-forth) from to do our calculations."

Well that makes more sense. The problem then is that people such as the spreadsheet author are positing that there is no assortive mating going on by IQ, when obviously there is. When children of lawyers, doctors, professors and businessmen start courting the children of janitors, trash collectors or welfare queens, I guess using IQ=100 as the mean reverted to will make sense. Until then, not at all.

Anonymous said...

I can't think of one example of a smart person I know who did not have a smart parent, grandparent or some other ancestor who was not intellectually distinguished in some way.


I guess there's a lot of wriggle room in that phrase "intellectually distinguished in some way". You could argue that the illiterate peasant mother of Gauss was intellectually distinguished in some way. (Beyond being the mother of one of the all time great geniuses, that is) For all we know she was actually an excellent card player, for instance.

Anonymous said...

the regression to the mean math posited in this post, however, suggests that, given a level playing field, europeans will sort of struggle for control in a meritocracy with mestizos, because, well, their kids will almost always be 1 or 2 SDs dumber, putting them down in the range where the mestizos can credibly battle them for control of things.


Jody, you don't understand the concept of "regression to the mean", or the concept of genetics for that matter. They don't say anything at all about Europeans struggling for control in America because their children are always 1 or 2 SD's dumber.


Read and understand first, comment after.

Anonymous said...

even in my own family i can see that there is no regression to the mean. the average brainpower on my dad's side of the family remains in the IQ 130 range generation over generation. my mom's side of the family, who are white trash losers, stay firmly in the 100 range


It's not hard to see that you take after your moms side of the family.

Nick Diaz said...

@Jody

"this is why people who actually study this stuff with little political bias, know the united states is in deep long term trouble. because mestizos produce almost zero talented kids, in almost any field. and if i did want to make this topic about race, i'd point out how extremely unlikely it is that the great mexican wave which the US is experiencing today, is going to produce ANY geniuses. 40 million mestizos and probably, literally, ZERO geniuses will come out of it"

How many geniuses did the Scots-Irish give America? What about the Poles? Going by this(stupid) logic, the Scots-Irish should be kicked out of the U.S for lack of contributing. Better yet, what work of genius have YOU contributed to America?

Everything that is bei9ng said about Mexican immigrants today was said about Italian and Irish immigrants in the late 19th century: that they are indolent, violent, lacking in conscientiousness and, above all, unintelligent. Same song, diferente record.

Anonymous said...

Bill, Lion - I tend to agree that it all depends on what you mean by "the general population". What if your forebears have been marrying smart people for the last few hundred years - what's your 'general population'?

Anonymous said...

"Shakespeare's father was a highly prosperous artisan, and a big wheel in local politics"

That's if Shakespeare was actually Shakespeare. There is a degree of speculation that he wasn't.

http://en.wikipedia.org/wiki/Oxfordian_theory_of_Shakespeare_authorship

Obviously other exceptions can come from illegitamacy.

David said...

>Name 2<

While no idea is wholly original, the claim is that Dr. F's insights were crucial, for example influential. Two influential ideas: Freud is credited with the development of depth psychology (the operation and expression of the subconscious) and his tripartite theory of human personality (id, ego, superego).

I consider it a sign of the degeneration of any field, particularly in the humanities, that a purportedly academic education in it doesn't require reading. A lot of reading. Part of the credentialing inflation problem (which is discussed in a link that I posted in another comment here) is the reduction of college education to vocational training - handouts of material and hands-ons. One might assume that part of the equipment of a psychology student is an intellectual interest in his subject, even to the outrageous extent of doing extra-curricular reading (at least pre-course); maybe even to the extent of seeking out Freud, Jung, Skinner, and the critical take-downs of them - out of curiosity. One might assume that, but one would be wrong nowadays. It is usually about putting food on the table (in lean times) or getting a Mercedes-Benz (in fat times) instead.

The appropriateness of putting material concerns first and last depends on the program, I guess, but what I strongly resent is a materialist cult trampling everything in this country including academia.

Someone running an auto-mechanics institute or offering courses of study in councelling shouldn't pretend that he is creating "Masters" or "Doctors of Philosophy." That pretense debases the degrees, harms his country, and a fortiori swindles his students.

Glaivester said...

Does regression to the mean decrease pretty rapidly after the first generation, if you keep looking at entire families and not just individuals?

For example, you give the example of two paretns with 160 IQs having kids with an average IQ of 136. But if an average kid from this family mated with another kid with an IQ of 136 who had parents with 160 IQs, would they not have smarter kids than if the other kid was a random 136 IQer?

Put another way, taking the highest-IQ people over several generations, would we not increase the probability that those people we selected had higher heritable IQs rather than a random hard-to-reproduce lucky combination of genes?

Anonymous said...

"Shakespeare's father was a highly prosperous artisan, and a big wheel in local politics"
That's if Shakespeare was actually Shakespeare. There is a degree of speculation that he wasn't...Obviously other exceptions can come from illegitamacy.


Yes, I just knew once the question of Shakespeare of Avon's parents' standing came up the Oxfordians would raise their heads out of the fever swamp. It will never cease to amaze me that one of the paleocons of legend, the late Sobran, adopted what is so patently an analogue to 'blue state coastal elitism' in literary history: "Oh no, it would have just been impossible for a white boy from the horseover country to have been intelligent enough to have written those plays. It just had to have been one of us SWPLs, who went to the Right Schools, said the politically acceptable things at Court, never got his hands dirty with anything like real work, and spent semesters abroad. Oh, and like us he had to have been so far beyond mere conventional heterosexuality."

If the Oxfordian theory, shot through of holes as it is, has achieved any recent revival in the past few years, it is primarily as one more manifestation of the coastal elites' hatred of those unspeakable people out in the sticks.

Anonymous said...

"(I coined the term "lesbian eugenics" to summarize the issues that lesbian would-be mothers confront in picking a sperm donor, but it hasn't caught on. After all, as we all know, lesbians are Good and eugenics is Bad, so ... Does Not Compute!)"

Yes, that must be why. It's not that you're a nonentity with small influence. No, can't be it. At all.

Anonymous said...

Something is wrong with these figures. I think you are making unwarranted assumptions - e.g. that the ancestors of the highly intelligent had a mean IQ of 100 and that is the mean that such a person's children will regress to.

Anonymous said...

I think you are making unwarranted assumptions - e.g. that the ancestors of the highly intelligent had a mean IQ of 100


Assuming that the person is question is a "European" or "Euro-American" then that assumption is not only warranted, it's a stone cold certainty once you look a sufficient numbers of ancestors.


You have 1,024 ancestors from ten generations ago. The average intelligence of those 1,024 people is bound to be very close to ... average.

misty said...

"One might assume that part of the equipment of a psychology student is an intellectual interest in his subject, even to the outrageous extent of doing extra-curricular reading (at least pre-course); maybe even to the extent of seeking out Freud, Jung, Skinner, and the critical take-downs of them - out of curiosity."

I don't disagree. In fact, I've experienced considerable frustration that university departments select the filter of a critical or theoretical approach for their students. In order to avoid a mismatch between the narrow focus established by a department and his own inclinations, the student would have had to learn the basics of a field of study and compare several university departments before picking a school.

Overall I get a sense of redundancy in our university system as well; partly from specializing too early. Social science departments provide opportunities tailored to their professors interests. After the first few semesters, Literature departments delve into literary criticism at the expense of broad reading of primary texts. This makes no sense because most social science and liberal arts majors require an advanced degree before a student can pursue a related career which means the graduate program looks a lot like the final two years of the major. For most of us, the last two years of high school overlap greatly with the first two years of college. Surely there is time for some exploratory reading that can be guided by a professor or TA.

That being said, I was bound and determined to expand my knowledge of some of the subjects I pursued in college. So, rather haphazardly throughout adulthood, I've seen recordings of every Shakespeare play, read Skinner's Walden II, Howard Gardiner's Multiple Intelligences. I read up on what was current in neuropsych 15 years ago which is now out of date, read some Oliver Sacks which is fun, fun, fun. Oh, and I have read at least one work by Jung, Man and his Symbols; probably read Interpretation of Dreams but ignored it for more transactional analysis approaches and, believe it or not, Probst's Reader Response Theory. I believe anyone can work with dream meaning but not everyone can use Freud to do it, nor should they have to.

I only have a little to offer in the sense of evaluating an academic field though. What I really wanted to do was be able to grapple with feelings, ideas, film and literature without necessarily having to rely on someone else's expertise. I can make some sort of meaning of just about anything be it dream, poem or surreal film. I have to admit, however, the lyrics to rock music frustrate me no end, often requiring a surprising amount of research if you aren't in on things. LOL



James B. Shearer said...

Bill asked:

I always feel clueless when this particular topic come up. Can you suggest a link, article, or book which explains how regression to the mean in IQ works? Its hypothesized mechanisms, how the math works, and etc?

A simple example which illustrates what is going on is taking 2 different IQ tests. On the average your score on the second test will regress towards the population mean. So if for example you scored 120 on the first test you might be expected to score about 115 on the average on the second test and if you scored 80 on the first test you might be expected to score about 85 on the average on the second test. This is because IQ tests are not precisely accurate you can be a bit lucky or unlucky on a given test and score a bit higher or lower than your actual IQ. This can be (for example) because of guessing on multiple choice questions or because when the constructor of the test picked 1 out 5 potential questions of equal difficulty he happened to pick the one question you could (or couldn't) answer correctly. So if for example you scored 120 this could be because your true IQ is 115 and you got a bit lucky or because your true IQ is 125 and you got a bit unlucky. But since IQ is distributed in a bell shaped curve there more people whose true IQ is 115 than whose true IQ is 125 so it is more likely that you got a bit lucky than a bit unlucky and so if you take the test again with average luck you are likely to score a bit lower. Similarly if you originally scored below 100 it is more likely you were a bit unlucky than a bit lucky and you will on average do better on the second test.

An important point is that this does not mean the scores on the second test will be bunched more tightly around 100. This is because although a score of say 120 is more likely to go down 5 points than a score of 115 is to go up 5 points there are enough more people at 115 (and near the center in general) that the people scoring higher will balance the people scoring lower and the shape of the distribution won't change.

As has been mentioned before the situation is symmetric. If you look at the score on the second test and use it to predict the score on the first test you will see the same movement (regression) towards the mean score.

ben tillman said...

There seems to be glut of people commenting on iSteve claiming to have or know someone with a 160 IQ....

I'd say after a life time in academia in a top ten school I've run across maybe three in my STEM career. Usually you can identify one by how quickly and precisely he talks and reasons.


If they're so rare, how can you possibly identify one? Do you administer IQ tests? Or do you just compare them to yourself?

If so, you would have to have an IQ of at least 150 or 155 to begin to guess, but you would probably need a full 160 so that it becomes a straightforward matter of "is he or isn't he smarter than I?" And if you have a 160 IQ and are here (representing a full 25% of all such people you have known), why would you be surprised that other such people are here? This is, after all, the blog of a man whose IQ is between 145 and 160.

In any event, being privy to the test scores of one commenter, I am sure that his IQ is 160+, and I would be shocked to learn that the IQ of a less-frequent commenter (Jim Bowery) had not also been measured at 160+. Then there's RKU, who sometimes shows glimpses of the extraordinary intelligence that's been attributed to him. However, I find his intelligence difficult to quantify.

Anonymous said...

A Slovenian TV programme that tried to prove top models were brainless bimbos was scrapped after a beauty queen turned out to have a higher IQ than a nuclear physicist. Iris Mulej, a former Miss Universe contestant, was found to have an IQ of 156 by scientists working for the programme makers.

The test result forced Slovenia TV, the state broadcaster, to cancel its programme involving the model who left school at 16 to pursue a modelling career. A spokesman for Bronz Model Management that represents Iris, 22, said: "They couldn't really do a programme making fun of dumb models when she turned out to be smarter than anyone else on the programme. "They are now wondering if they can do a different programme about the world's smartest model, and are trying to persuade Guiness to accept it as a record category."


HBD nerd's ideal waifu, but there's a hitch:

Iris, who previously admitted one of her ambitions was to have sex with one guy and three other girls, was Slovenia's Miss Universe contestant in 2002.


LOL

Anonymous said...

someone mentioned volkmar weiss above, a good article by him:

The middle class, to which in industrialized countries about a third of the population belongs, determines by its number of children whether the society goes up or down in the cycle. The offspring of the middle class supplies the largest percentage of socially upward mobile individuals and in each generation the highest absolute number of the highly gifted, with an IQ above 123 (Weiss, 1992). The highly gifted originate only to a small degree from the marriages of the highly gifted themselves, because the highly gifted proportion of any population is always very small. Beginning in the rising phase, with the formation of a meritocratic society, with the expansion of the educational system and by educational selection, nearly all gifted from the lower classes are sieved out. In the end nearly all women with medium and high IQ can be found in corresponding jobs and occupations, which makes the rearing of a large number of children difficult. The childlessness or child paucity of the upper third of society has the consequence that average IQ is decreasing, and the cycle enters its phase of descent, which is now being reached world-wide (Itzkoff, 2003b).

http://www.v-weiss.de/cycle.html

"In the tenth century, a similar
tendency was observable in the Arab Empire, the women demanding admission to the professions hitherto monopolised by men.
‘What,’ wrote the contemporary historian, Ibn Bessam, ‘have the professions of clerk, tax-collector or preacher to do with women?
These occupations have always been limited to men alone.’ Many women practised law, while others obtained posts as university
professors. There was an agitation for the appointment of female judges, which, however, does not appear to have succeeded. "

The Fate of Empires by Sir John Glubb

Anonymous said...

"You have 1,024 ancestors from ten generations ago. The average intelligence of those 1,024 people is bound to be very close to ... average."

Not necessarily. There may be a few exceptions, but mostly people stick to their own classes. Snobbery is a good mechanism for preventing higher classes from marrying lower classes. Few people want to marry down. Class consciousness has been in effect for hundreds of years, so if you are upper class you probably have had middle to upper class ancestors for the majority of the 1024 ancestors you had 250 years ago.

misty said...

Other than the explanations about statistical reasoning, most of you are making things up about intelligence. It's surprising that no one on this blog has a psychology background. Although the commenter known as Jody insists you could determine all with some electrodes attached firmly to the test subjects head.

Then there are the Victorian females disturbingly brandishing the test scores of male relatives before them to attract mates. I guess they're promising to incubate super smaht babies for any genius attracted to her brother's SAT score. Ew.

Someone who posts here must be good-looking to inspire such competition among nerdy babes. Though I'd imagine there are better sites for fostering a mensa romance. Mostly these guys are middle age, set in their ways and not going to read anything outside of what they learned in college 30 years or more ago. They'll have baggage in the form of wives, potbellies and comb-overs too. Oh, almost forgot, one of the wives still thinks aging dweeb boy is hot so periodically makes intimidating comments directed at any predatory female visitors to the guys' hangout here.

Much worthwhile discussion about brains? No, not for a very long time.

And, no, I'm not trolling for a date here. The guys are either too young for me or completely broken in. I'd prefer a free spirit of a suitable age who'd mostly avoided romantic entanglements along the way. Won't find that anywhere.



Anonymous said...

@ James B. Shearer:

I think the best unbiased estimate of an individual's score on the next examination would be the sample mean of their previous scores. In your example, the sample mean is 120, not 115.

Neil Templeton

Anonymous said...

"You have 1,024 ancestors from ten generations ago. The average intelligence of those 1,024 people is bound to be very close to ... average."

I (like everyone else) have 1,024 ancestors from ten generations ago but (virtually) all of them were Ashkenazi Jews, so chances are their intelligence was above average. If the mean that people regress to is always 100, then a higher (or lower) subgroup mean is impossible, but we know that these exist. If they exist by race or religion, why can't they exist by social group as well? "Belmont" and "Fishtown" are each marrying their own kind (when Fishtown bothers to get married at all) and I suspect they have for quite some time now.

Anonymous said...

Misty, I think you've unintentionally given us an insight into how women's minds really work. Men are supposedly obsessed with sex but (speaking for myself at least) romance is the farthest thing from our minds when we come to this site. When we are talking about IQ we are really talking about IQ - as Freud said (or maybe did not say), sometimes a cigar is just a cigar. Apparently this is not so for some women.

K

Anonymous said...

There may be a few exceptions, but mostly people stick to their own classes.


There is no historical correlation between social class and intelligence. The Queen of England seems like a nice woman, but she shows no signs of being exceptionally intelligent just because she is the product of centuries of deliberate breeding between members of the "upper classes".

Anonymous said...

I (like everyone else) have 1,024 ancestors from ten generations ago but (virtually) all of them were Ashkenazi Jews, so chances are their intelligence was above average


All the evidence we have - which is far from conclusive, I admit - suggests that Ashkenazi Jews of 250 years ago were not of greater than average IQ.

And let me take this opportunity to once again point out that the figures widely cited - often by Jews themselves - for modern Ashkenazi Jewish IQ are very inflated. One routinely sees figures ranging from 114 to 120 being bandied around. In fact the best evidence is that the average IQ of "Euro-American Jews" is about 105.

Uriah said...

"Nick Diaz said...

@Jody

"this is why people who actually study this stuff with little political bias, know the united states is in deep long term trouble. because mestizos produce almost zero talented kids, in almost any field. and if i did want to make this topic about race, i'd point out how extremely unlikely it is that the great mexican wave which the US is experiencing today, is going to produce ANY geniuses. 40 million mestizos and probably, literally, ZERO geniuses will come out of it"

How many geniuses did the Scots-Irish give America? What about the Poles? Going by this(stupid) logic, the Scots-Irish should be kicked out of the U.S for lack of contributing. Better yet, what work of genius have YOU contributed to America?

Everything that is bei9ng said about Mexican immigrants today was said about Italian and Irish immigrants in the late 19th century: that they are indolent, violent, lacking in conscientiousness and, above all, unintelligent. Same song, diferente record."


- Nicky: The Irish and Italians 'became white' over a few generations, pulled themselves up by their bootstraps and became competent contributors. Mexicans and other Hispanics (with the exception of perhaps Cubans, who are among the whitest) tend to become less prosperous, more net tax eaters, than their immigrant ancestors after a few generations.

Anonymous said...

What makes you think IQ has risen? Or more to the point, what makes you think that intelligence has risen?

Compared to Ugg & Lugg living in a cave?

Elsewhere in this thread its said that Ashkenazi average IQ has increased. How can that be if regression to the mean bites all the time.

If they very lowest IQ people dont reproduce would that not start to have an effect over time?

Yellowman Red said...

" Anonymous said...

There seems to be glut of people commenting on iSteve claiming to have or know someone with a 160 IQ. That's a really rare number, essentially being the highest valid score on an IQ test. Additional talents like photographic memories and mental math abilities may accompany a super-genius IQ, but not necessarily."




- Exactly. A 160 is the level of a nobel prize winner in Physics.



"Usually you can identify one by how quickly and precisely he talks and reasons."


-No. They are very rare, probably too rare for one individual to get a representative sampling unless they specifically set out across the country (or world) to interview supergeniuses. But even among the top supergeniuses, some have not behaved this way, based on historical record.

James B. Shearer said...

Neil Templeton said

I think the best unbiased estimate of an individual's score on the next examination would be the sample mean of their previous scores. In your example, the sample mean is 120, not 115.

No for the reason I gave. I found another attempted explanation on the web. This gives the following argument. Suppose these are very bad IQ tests such that the results are entirely random. Then your expected score on the second test will be 100 regardless of what you scored the first time. This is 100% regression to the mean. Now imagine the test isn't entirely random just mostly random. Now the regression won't be 100% instead if you score say 110 you might expect to score 101 the second time (90% regression). As the test gets more accurate the amount of regression to the mean will go down but as long as the test isn't perfect you will still expect some.

The above all assumes there is no practice effect from taking IQ tests. If there is the overall average score will rise a bit with repeated testing and this will also have to be accounted for.

ben tillman said...

I (like everyone else) have 1,024 ancestors from ten generations ago but (virtually) all of them were Ashkenazi Jews....

No, it's extremely unlikely that you have 1024 ancestors from 10 generations ago. Probably more like 800 or 900. Perhaps far fewer.

Anonymous said...

"What makes you think IQ has risen? Or more to the point, what makes you think that intelligence has risen?"

Compared to Ugg & Lugg living in a cave?




Given the "reasoning" on display in that comment (and several more like it here) I think it's obvious that the average intelligence of people alive today is not in excess of that of your imaginary cavemen.


Elsewhere in this thread its said that Ashkenazi average IQ has increased. How can that be if regression to the mean bites all the time


"Bites all the time"? Stop with your high IQ techno-babble!

Regression to the mean does not preclude the existence of sub-populations within the larger population, sub-populations which for a few generations may be taller or shorter or stronger or weaker or smarter or dumber than the overall population. It does tell us that these sup-populations will, of course, regress to the mean over time. Or to put it in simple language for you - what goes up must come down.

Anonymous said...

@ James B. Shearer

Certainly if the test results are drawn from a distribution with mean of 100, your logic holds. I was working from an assumption that the test measured skill, or intelligence of some kind.

Given this, if an individual takes the test a number of times (with no practice effect), his test results should behave as if they were drawn from a Normal distribution with unknown mean. This mean would indicate his "IQ".

For each iteration of the test, his expected score is the unknown mean. Since the sample mean in this case is an unbiased estimator of his personal mean or IQ, the sample mean is the best estimate of his next score.

The idea here is that his scores will cluster around the mean of the distribution of his scores, not around the general population mean. Since we don't know what his mean is, our best guess is the sample mean of his previous scores.

What you seem to be saying is that if he takes the test an infinite number of times, we will expect his sequence of scores (or average of scores) to converge to the general population mean. This only makes sense if his mean IQ equals the population mean.

Neil Templeton

Anonymous said...

I (like everyone else) have 1,024 ancestors from ten generations ago but (virtually) all of them were Ashkenazi Jews....

No, it's extremely unlikely that you have 1024 ancestors from 10 generations ago. Probably more like 800 or 900. Perhaps far fewer.

Yes far fewer as there would be more common ancestors the farther you went back.

Anonymous said...

If there are racial and ethnic means then mustn't there also be family means?

Over time individual family means are likely to coalesce within the ethnic mean because sooner or later someone in the family line will marry someone for their looks or personality etc rather than their brains but for as long as it lasts wouldn't a 138-mean family produce more 160 people on average?

The real question then is what makes a family mean last longer?

Until recently i'd say most men above a certain level of prosperity never considered female intelligence as a factor seeing as they weren't marrying for the conversation.

(I think there has always been an exception here among people in the precarious part of the middle i.e. prosperous but without much of a safety buffer, who i think have always looked for a similar level of intelligence in a wife e.g. i wouldn't be surprised if the lowest level of variance in spousal IQ was at this level.)

So what set families like the Darwins and the Huxleys apart may have been them having another trait which made them specifically attracted to intelligent women which meant they maintained their family mean IQ for longer than the standard 2-3 generations?

.
It seems to me even if Ashkenazi were dumb as rocks in 400AD or whenever it was they got the monopoly of banking from the Church that monopoly effectively created a sealed-in ecosystem which would have selected for verbal and cognitive ability with a Clark-type "Farewell to Alms" effect.

I can't see how having the banking monopoly couldn't have this effect as long as marriage was kept endogamous - which i assume it mostly was by virtue of the religion.

(Very similar to the Paris in terms of having endogamous marriage within a particular economic niche.)

If this did happen then a population who are selecting more on IQ than another population must by definition be selecting *less* on other traits like health for example, so if the mechanism is direct selection on IQ then the result should be a higher average IQ but a lower average in whatever other traits were less selected for as a result.

I think that follows.

If there's no evidence of Jews 250 years ago being smarter then maybe the time spent in little villages in eastern europe after the expulsion had a negative effect?

If so then something might have happened since to reverse those negative effects - like adopting the north euro marriage model maybe?

James B. Shearer said...

Neil Templeton said:

What you seem to be saying is that if he takes the test an infinite number of times, we will expect his sequence of scores (or average of scores) to converge to the general population mean. This only makes sense if his mean IQ equals the population mean.

No, his average will converge to his actual IQ. But you don't know his actual IQ after after 1 test and the best estimate is regressed towards the population mean.

Think of it this way. Suppose you haven't given him a test at all. Is his IQ more likely to be 115 or 125? The answer is 115 because we know there are more people with IQ 115 than 125. Now suppose you give him an IQ test and he scores 120 and you ask whether his true IQ is more likely to be 115 or 125. Assume the test reports a result x+y where x is his true IQ and y is a normal random variable with mean 0 and standard deviation say 5. Then it is equally likely that a person with true IQ 115 will have tested IQ 120 as that a person with true IQ 125 will have tested IQ 120. But there are still more people with IQ 115 than 125 so you are more likely to be seeing a person with IQ 115 testing 120 than a person with IQ 125 testing 120. Similarly for 118 versus 122 or in general 120-z versus 120+z. The net result is his true IQ is more likely to be less than 120 than greater than 120 and the best estimate of his score on future IQ tests will reflect this.

If you can program it shouldn't be too hard to simulate this and convince yourself.

Cail Corishev said...

Exactly. A 160 is the level of a nobel prize winner in Physics.

I'd guess that such a person's IQ would skew heavily toward certain areas. We're all aware here that a single IQ score is an average of multiple scores. A top physicist might score more like 180-200 on physics-type skills and 140 or less on something like verbal skills.

Another high-IQ person might be more of a jack-of-all-trades, good at learning everything but not having a particular area of excellence to concentrate on. Or his interests might lead him to excel in an occupation that doesn't lend itself to riches or well-known awards.

People like to cite Bill Gates as a super-smart guy, but there were plenty of other programmers around at the same time who were as smart or smarter than him. Great wealth or fame requires more than high IQ; you may also need ambition, sociability, good timing, connections, and a certain amount of luck.

Considering Steve's focus on IQ, it's hardly surprising that he would attract a higher number of high-IQ commenters than you'd expect from the general population.

Anonymous said...

No, it's extremely unlikely that you have 1024 ancestors from 10 generations ago.


It's a 99.99999% certainty that you have 1024 ancestors from ten generations ago, assuming you are of European extraction. Christian Europe took a dim view of brothers marrying their sisters or fathers marrying their daughters. In fact Christian law controlling even cousin marriage was elaborate and far-reaching and required marrying outside of ones extended family and not just outside ones immediate family.

Now, it's true that if you go back far enough - much further than ten generations, to something like 100 or 1000 or 10,000 generations - the math breaks down and your theoretical number of ancestors from 6000 years ago exceeds the total human population of that time.

But unless you're from Africa and barring cases of incest in your family, you certainly do have 1024 ancestors from ten generations ago.

Anonymous said...

It does tell us that these sup-populations will, of course, regress to the mean over time. Or to put it in simple language for you - what goes up must come down.

Regression to the mean implies no evolution then? We have the same IQ as some amoeba a zillion years ago.

Anonymous said...

Regression to the mean implies no evolution then? We have the same IQ as some amoeba a zillion years ago.


It's like you are being deliberately stupid.

Evolution does not imply "Progress". Evolution does not imply that things must always naturally evolve in the direction of higher levels of complexity, higher levels of sophistication, greater strength, greater intelligence. Sometimes those things may come about as a temporary and accidental side product of evolution, but they are not the point of it.

Regression to the mean does not imply no evolution, any more than the second law of thermodynamics (isolated systems spontaneously evolve towards thermodynamic equilibrium) implies that no human or automobile or aeroplane or star can possibly exist.

Go back to your social studies class and leave the science to people who understand it.

ben tillman said...

It's a 99.99999% certainty that you have 1024 ancestors from ten generations ago, assuming you are of European extraction. Christian Europe took a dim view of brothers marrying their sisters or fathers marrying their daughters. In fact Christian law controlling even cousin marriage was elaborate and far-reaching and required marrying outside of ones extended family and not just outside ones immediate family.


You could possibly be more wrong. Almost no one has 1024 ancestors 10 generations back.

I know that I don't have 1024. I've seen the genealogy. I know that my wife doesn't. I've seen the genealogy.

Your "99.99999% certainty" for descendants of European Christendom works out to 70 out of a worldwide population of 700 million Whites. Queen Victoria (who married her first cousin) alone has more than 70 living descendants.

John Adams married a third cousin. Thomas Jefferson married his third cousin. FDR married a fifth cousin once removed. Darwin married a first cousin and had 10 children with her. John Calhoun married a first cousin once removed. JFK's grandfather married a second cousin. Martin Van Buren married a first cousin once removed. Francis Marion married his first cousin. These couples alone have thousands upon thousands of living ancestors less than 10 generations removed from them. Throw in all the marriages between anonyomous first, second, third, fourth, and fifth cousins (who have no idea they're even related), and almost no one will avoid "pedigree collapse" for a full 10 generations.

Anonymous said...

Your "99.99999% certainty" for descendants of European Christendom works out to 70 out of a worldwide population of 700 million

What?

That's so stupid I can't even figure out how to begin refuting it. A "99.99999% certainty" is a probability, it is not a quantity. It cannot "work out" to 70, or to any other number.


Queen Victoria (who married her first cousin) alone has more than 70 living descendants

Yes. So? That's the the other side of have lots of ancestors - going forward in time one person may have a lot of descendants, just as looking back in time one person has a lot of ancestors. And the point of all this is that a pool of "a lot" of people is going to tend towards the average in all sorts of ways.

I know that I don't have 1024. I've seen the genealogy.

I'm intrigued by what you are selling and would like to hear more. So tell me (a) exactly how many ancestors you had ten generations ago and (b) which of them were marrying their own daughters and/or nieces.

Anonymous said...

John Adams married a third cousin. Thomas Jefferson married his third cousin. FDR married a fifth cousin once removed. Darwin married a first cousin and had 10 children with her. John Calhoun married a first cousin once removed. JFK's grandfather married a second cousin. Martin Van Buren married a first cousin once removed. Francis Marion married his first cousin. These couples alone have thousands upon thousands of living ancestors less than 10 generations removed from them.



Is English your native language? The stuff about "these couples" - all of them dead for centuries now - having "thousands upon thousands of living ancestors less than 10 generations removed from them" defies either logic, the rules of English, of the laws of biology. I can't say which since I'm unclear what you are trying to say.

Yes, Jefferson had thousands upon thousands of ancestors (the great majority of them deceased by the time he was born) but that is precisely the point you are arguing against. Those "thousands upon thousands" of ancestors - Jeffersons thousands, your thousands, my thousands, Joe Public's thousands - will when examined as a group tend towards the average: the average in height, the average in weight, the average in strength, the average in IQ, the average in everything.

Jefferson has "thousands upon thousands" of descendants alive today. I've seen the figure 5,000 mentioned, though its hard to know exactly how many there are as some are always dying and new ones being born. But let's go with 5,000. If you were to examine those 5,000 people there is a high probability that their average IQ would be very close to 100 - in spite of the fact that TJ's IQ was well above that.

Anonymous said...

@ James B. Shearer:

I believe the term "regression to the mean" comes from examination of a simple regression on one predictor variable, where the constant b0 is greater than one, and the slope coefficient b1 is between 0 and 1.

For instance, assume that regressing Child IQ on Parent IQ results in the equation: Child IQ = 40 + 0.60 * Parent IQ. Here the slope coefficient is "heritability". So if parent IQ = 160, then expected child IQ = 136, and if parent IQ = 60, then expected child IQ = 76. This is regression to the mean.

If one observed the scatterplot of Child IQ (y-axis) on Parent IQ (x-axis), it would look like an elongated cloud of points sloping upward with slope equal to 0.6.

However, if one were to observe the scatterplot of points representing our example agent's current IQ score on his previous IQ score, the plot would simply be a cloud of points with no trend, centered at x-120, y-120 (assuming the unknown mean actually equals 120). A simple regression of current score on previous score would give a result very close to: Y = 120 + 0.0 * X. The value of the slope coefficient would be essentially zero, because there is no trend. Again, the expected value of any score is 120, the unknown mean, and the sample mean is an unbiased estimator of this unknown.

You are assuming that the error "y" is normally distributed with mean 0 and s.d. = 5. So the distribution of error is symmetric with mean = 0, yet you argue that it is probable that he erred "high" on his first iteration of the test. That is, given his first result of 120, we should assume that his actual IQ is less than 120 and that therefore his "error" was biased high on the first test. This contradicts your assumption of unbiased error.

Neil Templeton

Cail Corishev said...

[Thomas] Jefferson has "thousands upon thousands" of descendants alive today. I've seen the figure 5,000 mentioned, though its hard to know exactly how many there are as some are always dying and new ones being born. But let's go with 5,000. If you were to examine those 5,000 people there is a high probability that their average IQ would be very close to 100 - in spite of the fact that TJ's IQ was well above that.

True, because most of the time they (including Jefferson himself) would have procreated with less intelligent people over the years. But what some seem to be saying is that if Jefferson had married an equally intelligent woman, and their children had married people of equal intelligence to themselves, and so on down through the generations, they would still inevitably have dipped down to average by today. That is harder to believe.

Anonymous said...

@ James B. Shearer:

Given an observed score of 120 on the first test, I agree it is more probable that the true mean equals 115 than that it equals 125. However, it is also more probable that the true mean equals 116 than that it equals 115, and it is more probable that the true mean equals 124 than that it equals 125 (ignoring the fact that points technically do not have probability in a continuous distribution).

As we home in on 120 from below and from above, the probability that we are capturing the true mean increases. And the difference in probability between above and below decreases.

For instance, it is more probable that the true mean lies between 119.98 and 119.99 is greater than the probability that the true mean lies between 120.01 and 120.02, but the difference in probability is very small. And the probability that the true mean lies in the interval 119.995 and 120.005 is greater than for either of the other two intervals.

Neil Templeton

James B. Shearer said...

Neil Templeton said:

You are assuming that the error "y" is normally distributed with mean 0 and s.d. = 5. So the distribution of error is symmetric with mean = 0, yet you argue that it is probable that he erred "high" on his first iteration of the test. That is, given his first result of 120, we should assume that his actual IQ is less than 120 and that therefore his "error" was biased high on the first test. This contradicts your assumption of unbiased error.

No it doesn't because we have additional information. We know he scored above average on the test and that tells us the random error was more likely positive than negative for him. If he had scored below average than we would know the random error was more likely negative than positive.

Suppose all the people we tested had true IQ 100. Then the test would just be measuring the random error and we could tell exactly what it was but the random error would still be unbiased.

James B. Shearer said...

Regression to the mean implies no evolution then? We have the same IQ as some amoeba a zillion years ago.

No that isn't what it means. The examples are assuming high IQ and low IQ people have the same number of children to keep things simple. But if high IQ people are having more children than low IQ people than the average IQ will rise over time. And if low IQ people are having more children than high IQ people than the average IQ will fall over time.

ben tillman said...

I'm intrigued by what you are selling and would like to hear more. So tell me (a) exactly how many ancestors you had ten generations ago and (b) which of them were marrying their own daughters and/or nieces.

You're extremely confused. This has nothing to do with father-daughter or aunt-niece couplings.

You would have fewer than 1,024 ancestors ten generations ago if, for instance, one of your ancestors married a second cousin seven generations ago or if one ancestor married a sixth cousin three generations ago. The chance that you have 1,024 ancestors 10 generations ago approaches zero.

The posited 1024 ancestors at x-10 would have 512 children (x-9) who would form 256 mating pairs. If any of these pairs involve siblings or half-siblings (i.e., if they share a parent), the number at x-10 will be less than 1024.

The posited 256 ancestors at x-8 form 128 mating pairs. If any of these pairs involve first cousins or half first cousins, or siblings or half siblings (i.e., if they share a grandparent), the number at x-10 will be less than 1024. That there are no first cousin pairings out of 128 is unlikely (less than 28% if we assume first cousin pairings were just 1% of the total).

The posited 128 ancestors at x-7 form 64 mating pairs. If any of these pairs involve second cousins or half second cousins or closer relations (i.e., if they share a great grandparent) the number at x-10 will be less than 1024. That there are no such pairings out of 64 is very unlikely (about 14% if we conservatively assume pairings that shared a great grandparent were just 3% of the total).

And so on. As you get closer to the present generation, you have fewer ancestors but more and more distant cousins they must steer clear of to avoid pedigree collapse.

Having 1024 ancestors 10 generations back is extremely unlikely.

Anonymous said...

All the evidence we have - which is far from conclusive, I admit - suggests that Ashkenazi Jews of 250 years ago were not of greater than average IQ.

The average intelligence of Ashkenazi Jews 250 years ago could have been very high, but it would be difficult to estimate because they were so minimally involved in secular affairs at that time. The bulk of the population had transferred to less-developed Eastern Europe over the previous five centuries. Their occupations were restricted, and the community at that time was realing from the effects of the Khmelnitsky massacres followed by the false messiahs Shabtai Zvi and Jacob Frank. There was little internal impetus within the religous communities to join the secular world, and the secular world was not yet welcoming to Jews at that time.

Anonymous said...

No that isn't what it means. The examples are assuming high IQ and low IQ people have the same number of children to keep things simple. But if high IQ people are having more children than low IQ people than the average IQ will rise over time. And if low IQ people are having more children than high IQ people than the average IQ will fall over time.

Thank you James, I knew someone would come up with a straight answer eventually.

Anonymous said...

The average intelligence of Ashkenazi Jews 250 years ago could have been very high


Sure, it could. And the average intelligence of gypsies 250 years ago could have been very high. But there's no actual evidence to support either hypothesis.

Anonymous said...

You're extremely confused. This has nothing to do with father-daughter or aunt-niece couplings.


Of course it does. Those are some of the possible ways in which a person might have less than the theoretical number of ancestors. Cousin marriage is another possible way.


The chance that you have 1,024 ancestors 10 generations ago approaches zero.

The chance that I have 1,024 ancestors 10 generations ago approaches a certainty.

The posited 1024 ancestors at x-10 would have 512 children (x-9) who would form 256 mating pairs. If any of these pairs involve siblings or half-siblings (i.e., if they share a parent), the number at x-10 will be less than 1024.

Nothing wrong with your math. It's the "if" which is dubious.


Having 1024 ancestors 10 generations back is extremely unlikely.

Among inbred populations - Jews, for example - it is extremely unlikely. But among out-bred populations - the typical white American has ancestors from several different European counties who were certainly not related to one another - it is likely.

Anonymous said...

what some seem to be saying is that if Jefferson had married an equally intelligent woman, and their children had married people of equal intelligence to themselves, and so on down through the generations, they would still inevitably have dipped down to average by today. That is harder to believe.


It's a lot more hard to believe that that sequence of events you describe, in which TJ marries an equally intelligent woman, and their children marry people of equal intelligence to themselves, and so on and so on down through the generations, could ever occur in a world of human beings. The hypothesis sits atop an almost liberal lack of understanding of human nature.

But set aside the fact that real people do not behave as you would like them to. The other cause of regression to the mean is that, in addition to people not behaving as you would wish, genes do not behave that way either. It's depressing that so few people commenting on this erstwhile "HBD blog" seem aware of the reality of recessive genes.

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