Steve, one should not be reporting decimal points for IQ. The test does not measure to that accuracy. One should probably be rounding off to the tens such as 90, 100, and 110 to avoid implying a precision that the test do not really have.
> One should probably be rounding off to the tens such as 90, 100, and 110 to avoid implying a precision that the test do not really have.
Your numbers are ridiculous. Rounding IQs to the nearest ten points would be analogous to rounding heights to the nearest four inches. The tests are far more precise than 𝘵𝘩𝘢𝘵.
(Six-inch standard deviation of [adult male] height taken from https://www.cdc.gov/nchs/data/series/sr_11/sr11_252.pdf , table 11/12. For non-hispanic white adult males the standard deviation is 3.66 inches and IQ-to-the-nearest-ten-points is "only" as stupid as rounding your height to the nearest 2.5 inches.)
If one is measured repeatedly, one gets the same height. IQ tests can vary by up to 8 points with repeated testing. That is why there is no real difference between 95 and 105.
The thing that jumps out to me is that several pairs with similar education levels still have ~10 point differences. That calls into question the significance of the ~10 point difference with dissimilar levels.
I have worked with identical twins and occasionally will notice a difference in cognitive skills.
One case one sibling had a kidney ailment that an older sibling also had but not the other twin. Presumably some environmental exposure for the 2 sick ones and a measurable difference in abstract and verbal reasoning.
Even the same womb can expose twins to unequal environments.
Through my experience I would say education can definitely move the needle in cognitive skills.
Environment does matter. You aren’t going to take someone with a 100 iq and take them to 140, but you can definitely improve their reasoning through education (and nutrition).
I would call this neuro-developmental noise. It doesn't have to be environmental. Basically, the way how axons from neurons in A go to territory B is overall strongly determined by preset cues (general direction and rostrocaudal, mediolateral gradient) but how fine ramification happens is mostly a game of chance. A similar developmental noise sometimes also occurs in the reading out of genes - some of it occurs with 100% stringency, but some of it can have a random, 70:30 character. So it's not impossible for one identical twin to have a kidney disorder due to a developmental "chance" and the other not to.
There is chance and chance. Let's say for reasons of simplicity if there is a gene X there is a 70% risk of a kidney disorder Y. Chance doesn't mean it is totally random, as in a totally global population.
Obviously, the twins may have that gene X, being identical. And there is a 50% of the older sibling having the gene X, being a full sibling. Nevertheless, only 2 out of 3 have the kidney disorder. Why? Because it is chance of 70%, even if having gene X.
By the way, it's not that uncommon. BRCA1&2 predispose to breast cancer. But it doesn't mean you will always get breast cancer if female BRCA1 or 2 positive.
Twin pair #87 are 64 and 62 IQ respectively but one of them made it through their junior year of high school and the other one had three years of schooling and 9 months of "business school" (what were they teaching--marbles, lunch money?) This makes zero sense; you can't "educate" someone whose literacy is basically the Dick and Jane workbooks. There are some other baffling entries as well.
87B was not attending business school to get an MBA; this was a school where one learned how to be a secretary and learned skills such as filing, typing, and taking shorthand. Perhaps with her IQ of 64 she failed out quickly
The well publicized story of the Colombian twins is fascinating. I believe what happen is they were born on different days but one of the country twins was very sick and a relative (not mother) took him to the city hospital where he got switched with one of the new born city twins. The country relative didn’t really know the baby well enough to recognize the switch ( or maybe another relative picked the newborn up). In any event, that’s closer to the way they were switched. There is a fascinating bioptic on the whole story. I think the accountant got the best end of the deal (I’m guessing he got the 22 pt advantage- far better than his butcher twin. The city twin raised in the country has since become a lawyer - good genes prevailed); it does highlight the value of nurture.
Twins raised apart, but "reunited by friends of their twins stopping them on the street to converse with their look-alikes" is a major motor of the plot in Shakespeare's Comedy of Errors, no? I wonder if the Bard had any particular insight into nature vs. nurture.
My untutored observation is that the IQ scores seem distinctly on the low side. I realise that this is a relatively small sample size, but my guess is that, if plotted on a curve, the left tail would be on the “fat” side.
I've got two hypotheses now. First, the data set of mismatched twins is skewed towards communities with low average IQ and low competence. Second, education is rather orthogonal to intelligence. I don't really see a clear pattern there. You get a PhD because you're smart; you're not smart because you have a PhD.
I agree. I’m a professor at an elite law school, and I can assure you that none of the students are smarter on the way out than they were on the way in.
Well, some are simply lazy and others can compensate to some degree with hard work, but the kids at pointy end on the way out were also at the pointy end on the way in. This is not to say that they don’t benefit from my instruction (after all, they don’t know anything about the subject matter at the beginning of their degrees), it is, however, to say that I’ve not seen evidence that we make them any “smarter”.
I once travelled across the US with three friends, two of whom were identical twins. We often encountered the problem of deadlock, because the twins would always vote en bloc for a particular activity. My strong conclusion after four weeks in a car with these two is that they were essentially one person spread across two, non-contiguous bodies. If I’m honest, it was more than a little creepy.
Unless I'm missing something, the table listings don't specify which twin, in pairs 71 and 72, outscored the other twin. They say one twin in each pair got 5 years of school and the other one got 16, and they say the difference in measured IQ between pair 71 was 7 points and between pair 72 was 22 points, but how do you know the city twins outscored the country twins?
(There is a footnote on their entries that says "IQ values supplied with permission by Segal, N.L. in personal communication", which is odd because the table doesn't display any IQ values.)
Pair 70 differed in that twin A attended four (4) years of school in a 'suburban area' while twin B attended one point five (1.5) years of school in a 'remote village' (both in China). The measured IQ difference is 25 points. This one makes me wonder whether there were e.g. nutritional differences.
Unrelatedly, I appreciate the fact that both twins in pair 3 are named Paul. There are some other pairs where I wonder whether they were named as a pair despite being raised apart, like Ada / Ida or Thelma / Zelma.
1) Important to keep in mind that the level of "heritability" of a trait is not fixed, but rather varies depending on the variance in environment ("nurture").
2) IQ is not intelligence, but rather a (reasonable but rough) test of intelligence.
3) We know how to make people dumb and how to make them "less dumb", but we do not (as of now) know how to make people smart.
4) The sort of variances we see between these identical twins--mostly driven by varying nurture--are not the same the differences we see between racial groups. (And yes, we do know this.)
Finally:
Nations that will "win"--that will thrive and prosper on into the future--will be nations that take genetics seriously and work to drive eugenic fertility. Sadly, the West is *completely* failing in this regard.
> 1) Important to keep in mind that the level of "heritability" of a trait is not fixed, but rather varies depending on the variance in environment ("nurture"). <
Repeating from my comment on Steve's previous post:
There is *no* *fixed* level of "heritability" or the nature/nurture ratio to be discovered. How much nurture matters relative to nurture depends pretty much entirely upon how much the nurture environment varies. (Ok, it also depends upon how much the genetics of your population under study varies as well. We're just taking that as a given.)
If your environments vary between "good nutrition, good medical care, as much schooling as desired" and "raised by wolves", then nurture is really going to put the whoop-ass on nature. The "raised by wolves" kids are going to do very, very poorly on an IQ test--assuming they don't flat out eat the test examiner.
However, what seems pretty clear from all the studies and data, is that in prosperous modern industrialized societies--like the contemporary US--where everyone gets adequate calories, the disease burden is low and there is decent universal public education, the observed phenotypic differences in IQ--and most all other traits--seem to be overwhelmingly due to nature. And furthermore, the remaining nurture component, does not seem to be family environment, nor particularly susceptible to any sort of public policy intervention, but rather mostly random "noise".
On of the ironies is that if the socialist world savers ever got their way and were able to enforce absolute equality--nutrition, parenting methods, socialization, schooling--of upbringing on everyone, then the remaining differences--which would still be stark--would be almost all due to genetics and some noise. The more you create social equality, the more the observed inequality is revealed as immutable genetics.
2) IQ is not intelligence, but rather a (reasonable but rough) test of intelligence.
IQ is not a direct measure of a trait (intelligence) like measuring height is for height. What an IQ test actually measures is the ability to do IQ tests. That correlates highly with intelligence, but it also very dependent on things like education and exposure to the sort of problems that are on IQ tests. It is a learned skill, like much else.
A analogy would be testing for "athleticism" by having people run a decathlon. If everyone test had no practice or exposure, then it might be a very rough but decent guide. However, if some people had school where they got some training to run, jump, throw and vault and others did not, then the correlation of results with actual athletic capability would be muddled. However, if everyone got at least reasonable training, then the results would be very predictive--at least for picking the people best at decathlon. Whether that squares up with "athleticism" is another question.
It would be very interesting if we had results for these separated twins of less educationally loaded more direct mental tests--like reaction time tests. I suspect we would find that these separate twins were much closer on those.
For example, William Canas--the Bogota born, country raised with 5 years of schooling, butcher shop manager--has a lower IQ than his city raised, college educated twin brother. But I would bet that he would peg much closer in a reaction time test. And I would bet that people consider him "smart" and that even now he would be much more capable of picking up new stuff. I.e. I suspect that his actual "intelligence" is higher than his IQ test results constrained by only 5 years of schooling.
JP Saxe, whom I have never heard of before today, just butchered O Canada live on FOX before Game 3 of the World Series. The second line of the anthem is supposed to be "Our home and native land". However Saxe changed it to...
> Our home on native land
which seems trivial, but it emphasizes that the white Canadians appropriated the land from the First Nations people. Some may say that by calling them FN I myself am engaging in political correctness but I wanted to distinguish them from the actual Indians who are quite ironically currently invading Canada
Several of these pairs have IQ scores in or near mental retardation territory. I wonder if that is a factor as to why they were raised apart.
Average IQ for 174 twins was 94.
Steve, one should not be reporting decimal points for IQ. The test does not measure to that accuracy. One should probably be rounding off to the tens such as 90, 100, and 110 to avoid implying a precision that the test do not really have.
> One should probably be rounding off to the tens such as 90, 100, and 110 to avoid implying a precision that the test do not really have.
Your numbers are ridiculous. Rounding IQs to the nearest ten points would be analogous to rounding heights to the nearest four inches. The tests are far more precise than 𝘵𝘩𝘢𝘵.
(Six-inch standard deviation of [adult male] height taken from https://www.cdc.gov/nchs/data/series/sr_11/sr11_252.pdf , table 11/12. For non-hispanic white adult males the standard deviation is 3.66 inches and IQ-to-the-nearest-ten-points is "only" as stupid as rounding your height to the nearest 2.5 inches.)
If one is measured repeatedly, one gets the same height. IQ tests can vary by up to 8 points with repeated testing. That is why there is no real difference between 95 and 105.
“I’ll take that one.”
The thing that jumps out to me is that several pairs with similar education levels still have ~10 point differences. That calls into question the significance of the ~10 point difference with dissimilar levels.
I have worked with identical twins and occasionally will notice a difference in cognitive skills.
One case one sibling had a kidney ailment that an older sibling also had but not the other twin. Presumably some environmental exposure for the 2 sick ones and a measurable difference in abstract and verbal reasoning.
Even the same womb can expose twins to unequal environments.
Through my experience I would say education can definitely move the needle in cognitive skills.
Environment does matter. You aren’t going to take someone with a 100 iq and take them to 140, but you can definitely improve their reasoning through education (and nutrition).
I would call this neuro-developmental noise. It doesn't have to be environmental. Basically, the way how axons from neurons in A go to territory B is overall strongly determined by preset cues (general direction and rostrocaudal, mediolateral gradient) but how fine ramification happens is mostly a game of chance. A similar developmental noise sometimes also occurs in the reading out of genes - some of it occurs with 100% stringency, but some of it can have a random, 70:30 character. So it's not impossible for one identical twin to have a kidney disorder due to a developmental "chance" and the other not to.
I'd have to admit that the presence of the same kidney disorder in a non-twin sibling makes it look less like chance.
There is chance and chance. Let's say for reasons of simplicity if there is a gene X there is a 70% risk of a kidney disorder Y. Chance doesn't mean it is totally random, as in a totally global population.
Obviously, the twins may have that gene X, being identical. And there is a 50% of the older sibling having the gene X, being a full sibling. Nevertheless, only 2 out of 3 have the kidney disorder. Why? Because it is chance of 70%, even if having gene X.
By the way, it's not that uncommon. BRCA1&2 predispose to breast cancer. But it doesn't mean you will always get breast cancer if female BRCA1 or 2 positive.
Twin pair #87 are 64 and 62 IQ respectively but one of them made it through their junior year of high school and the other one had three years of schooling and 9 months of "business school" (what were they teaching--marbles, lunch money?) This makes zero sense; you can't "educate" someone whose literacy is basically the Dick and Jane workbooks. There are some other baffling entries as well.
One is assuming an precision to IQ tests that probably does not really exist.
Tiny sample size, cursory data.
87B was not attending business school to get an MBA; this was a school where one learned how to be a secretary and learned skills such as filing, typing, and taking shorthand. Perhaps with her IQ of 64 she failed out quickly
The well publicized story of the Colombian twins is fascinating. I believe what happen is they were born on different days but one of the country twins was very sick and a relative (not mother) took him to the city hospital where he got switched with one of the new born city twins. The country relative didn’t really know the baby well enough to recognize the switch ( or maybe another relative picked the newborn up). In any event, that’s closer to the way they were switched. There is a fascinating bioptic on the whole story. I think the accountant got the best end of the deal (I’m guessing he got the 22 pt advantage- far better than his butcher twin. The city twin raised in the country has since become a lawyer - good genes prevailed); it does highlight the value of nurture.
Twins raised apart, but "reunited by friends of their twins stopping them on the street to converse with their look-alikes" is a major motor of the plot in Shakespeare's Comedy of Errors, no? I wonder if the Bard had any particular insight into nature vs. nurture.
My untutored observation is that the IQ scores seem distinctly on the low side. I realise that this is a relatively small sample size, but my guess is that, if plotted on a curve, the left tail would be on the “fat” side.
I've got two hypotheses now. First, the data set of mismatched twins is skewed towards communities with low average IQ and low competence. Second, education is rather orthogonal to intelligence. I don't really see a clear pattern there. You get a PhD because you're smart; you're not smart because you have a PhD.
I agree. I’m a professor at an elite law school, and I can assure you that none of the students are smarter on the way out than they were on the way in.
what do you think of the students who were considered smart on the way in, but did not end up with top grades?
Well, some are simply lazy and others can compensate to some degree with hard work, but the kids at pointy end on the way out were also at the pointy end on the way in. This is not to say that they don’t benefit from my instruction (after all, they don’t know anything about the subject matter at the beginning of their degrees), it is, however, to say that I’ve not seen evidence that we make them any “smarter”.
It's like you've never seen The Wizard of Oz.
OK sorry for tripping you with that mouse poop. Try this instead:
You don’t take calculus to get smart; you take calculus because you are smart.
It could be that if you wind up separated from your identical twins that your genetic parents might, on average, be poor decision makers?
I once travelled across the US with three friends, two of whom were identical twins. We often encountered the problem of deadlock, because the twins would always vote en bloc for a particular activity. My strong conclusion after four weeks in a car with these two is that they were essentially one person spread across two, non-contiguous bodies. If I’m honest, it was more than a little creepy.
Should have restricted the franchise to "one vote per genome".
Unless I'm missing something, the table listings don't specify which twin, in pairs 71 and 72, outscored the other twin. They say one twin in each pair got 5 years of school and the other one got 16, and they say the difference in measured IQ between pair 71 was 7 points and between pair 72 was 22 points, but how do you know the city twins outscored the country twins?
(There is a footnote on their entries that says "IQ values supplied with permission by Segal, N.L. in personal communication", which is odd because the table doesn't display any IQ values.)
Pair 70 differed in that twin A attended four (4) years of school in a 'suburban area' while twin B attended one point five (1.5) years of school in a 'remote village' (both in China). The measured IQ difference is 25 points. This one makes me wonder whether there were e.g. nutritional differences.
Unrelatedly, I appreciate the fact that both twins in pair 3 are named Paul. There are some other pairs where I wonder whether they were named as a pair despite being raised apart, like Ada / Ida or Thelma / Zelma.
I think that African-Americans have an IQ high than native African because they have European genes.
Four points and a general comment:
1) Important to keep in mind that the level of "heritability" of a trait is not fixed, but rather varies depending on the variance in environment ("nurture").
2) IQ is not intelligence, but rather a (reasonable but rough) test of intelligence.
3) We know how to make people dumb and how to make them "less dumb", but we do not (as of now) know how to make people smart.
4) The sort of variances we see between these identical twins--mostly driven by varying nurture--are not the same the differences we see between racial groups. (And yes, we do know this.)
Finally:
Nations that will "win"--that will thrive and prosper on into the future--will be nations that take genetics seriously and work to drive eugenic fertility. Sadly, the West is *completely* failing in this regard.
(I'll flesh these out a bit below.)
Fleshing out from above:
> 1) Important to keep in mind that the level of "heritability" of a trait is not fixed, but rather varies depending on the variance in environment ("nurture"). <
Repeating from my comment on Steve's previous post:
There is *no* *fixed* level of "heritability" or the nature/nurture ratio to be discovered. How much nurture matters relative to nurture depends pretty much entirely upon how much the nurture environment varies. (Ok, it also depends upon how much the genetics of your population under study varies as well. We're just taking that as a given.)
If your environments vary between "good nutrition, good medical care, as much schooling as desired" and "raised by wolves", then nurture is really going to put the whoop-ass on nature. The "raised by wolves" kids are going to do very, very poorly on an IQ test--assuming they don't flat out eat the test examiner.
However, what seems pretty clear from all the studies and data, is that in prosperous modern industrialized societies--like the contemporary US--where everyone gets adequate calories, the disease burden is low and there is decent universal public education, the observed phenotypic differences in IQ--and most all other traits--seem to be overwhelmingly due to nature. And furthermore, the remaining nurture component, does not seem to be family environment, nor particularly susceptible to any sort of public policy intervention, but rather mostly random "noise".
On of the ironies is that if the socialist world savers ever got their way and were able to enforce absolute equality--nutrition, parenting methods, socialization, schooling--of upbringing on everyone, then the remaining differences--which would still be stark--would be almost all due to genetics and some noise. The more you create social equality, the more the observed inequality is revealed as immutable genetics.
2) IQ is not intelligence, but rather a (reasonable but rough) test of intelligence.
IQ is not a direct measure of a trait (intelligence) like measuring height is for height. What an IQ test actually measures is the ability to do IQ tests. That correlates highly with intelligence, but it also very dependent on things like education and exposure to the sort of problems that are on IQ tests. It is a learned skill, like much else.
A analogy would be testing for "athleticism" by having people run a decathlon. If everyone test had no practice or exposure, then it might be a very rough but decent guide. However, if some people had school where they got some training to run, jump, throw and vault and others did not, then the correlation of results with actual athletic capability would be muddled. However, if everyone got at least reasonable training, then the results would be very predictive--at least for picking the people best at decathlon. Whether that squares up with "athleticism" is another question.
It would be very interesting if we had results for these separated twins of less educationally loaded more direct mental tests--like reaction time tests. I suspect we would find that these separate twins were much closer on those.
For example, William Canas--the Bogota born, country raised with 5 years of schooling, butcher shop manager--has a lower IQ than his city raised, college educated twin brother. But I would bet that he would peg much closer in a reaction time test. And I would bet that people consider him "smart" and that even now he would be much more capable of picking up new stuff. I.e. I suspect that his actual "intelligence" is higher than his IQ test results constrained by only 5 years of schooling.
O/T
JP Saxe, whom I have never heard of before today, just butchered O Canada live on FOX before Game 3 of the World Series. The second line of the anthem is supposed to be "Our home and native land". However Saxe changed it to...
> Our home on native land
which seems trivial, but it emphasizes that the white Canadians appropriated the land from the First Nations people. Some may say that by calling them FN I myself am engaging in political correctness but I wanted to distinguish them from the actual Indians who are quite ironically currently invading Canada
The concept of Genotypic IQ vs Phenotypic IQ needs to be mentioned in this discussion. And mentioned more in all discussions related to IQ.
There is an error in the description for Pair 72. It repeats the description for Pair 71.