A new survey of intelligence researchers: 90% think international IQ differences are partly due to genetics

[ApostateAbe]

Published in the last few days, a new survey of intelligence researchers by Rindermann, Becker and Coyle. They are the same authors who conducted a similar survey in 2013, but this one is about *international* racial intelligence differences, as opposed to the US black-white intelligence difference alone, and it is far more detailed. Out of all races/nations asked about, the intelligence placement of Western Jews is found to be MOST likely to be attributed to genetics, and the intelligence placements of Finland and Latin America were found to be LEAST likely to be attributed to genetics.

As before, the vast majority of intelligence researchers attribute intermediate significance to genetic differences overall. "The frequency of zero-percentage-ratings was larger for genes than for culture or education (about 1%), but experts who believed that genes had no influence were a minority: Around 90% of experts believed that genes had at least some influence on cross-national differences in cognitive ability."

It is generally at odds with what you may expect the "scientific establishment" to be, based on who gets the pop science/political loudspeakers, but it turns out that there is not just one "scientific establishment." There are many scientific establishments, and there is no issue where they are more at odds with themselves than the issues of human races and/or intelligence.

I should emphasize: just because the majority of intelligence researchers think this way does NOT mean you should agree with them. But it turns out they really do have good reasons for believing as they do, and it is a reason to open your mind about the issue, not to just dismiss a mainstream science based on ideological morals. Adherence to bad science for moral reasons is more likely to defeat your morals than to enhance them.

 

[Underseer]

You are obsessed with digging for rationalizations for white supremacy.

If genetics is a valid excuse for your attitudes about race, why isn't China the dumbest nation on the planet? They have been rounding up and executing large numbers of smart people every couple of centuries for most of not all of recorded history. While most civilizations have incidents like this, none other that I know of has done it on such a scale so regularly for such a long time.

If what you want to believe is valid, then the Chinese should be staggeringly stupid by now.

 

[untermensche]

Human cognitive abilities are derived from the expression of genes.

But there is no "IQ" gene and "IQ" is just a human construct that is very flexible and doesn't mean much.

 

[EgalitarianJay]

I wonder how familiar these IQ researchers are with experimental quantitative genetics and population genetics. If we took a group of geneticists and asked them survey questions about the role that genes play in racial differences in IQ how many of them would argue that it plays a significant or partial role? The researchers in this survey were psychologists. I'm not sure that the average psychologist including experts on intelligence testing are knowledgeable enough of genetics research to give an informed opinion on this subject.

 

[ApostateAbe]

You are obsessed with digging for rationalizations for white supremacy.

If genetics is a valid excuse for your attitudes about race, why isn't China the dumbest nation on the planet? They have been rounding up and executing large numbers of smart people every couple of centuries for most of not all of recorded history. While most civilizations have incidents like this, none other that I know of has done it on such a scale so regularly for such a long time.

If what you want to believe is valid, then the Chinese should be staggeringly stupid by now.

I know you said that before, and I am not challenging it, but I would love to get more information about it, if you happen to have any leads. If I remember correctly, I tried researching it, but I did not succeed finding any confirmation or disconfirmation.

 

[whichphilosophy]

You are obsessed with digging for rationalizations for white supremacy.

If genetics is a valid excuse for your attitudes about race, why isn't China the dumbest nation on the planet? They have been rounding up and executing large numbers of smart people every couple of centuries for most of not all of recorded history. While most civilizations have incidents like this, none other that I know of has done it on such a scale so regularly for such a long time.

If what you want to believe is valid, then the Chinese should be staggeringly stupid by now.

I know you said that before, and I am not challenging it, but I would love to get more information about it, if you happen to have any leads. If I remember correctly, I tried researching it, but I did not succeed finding any confirmation or disconfirmation.

This is because no one has established or provided an indefeasible theory (as in the theory of evolution) that genes determine intelligence.
We do find theories and research that sometimes suggests this but then replication does not seem to occur and other theories are formulated.

 

[ApostateAbe]

Human cognitive abilities are derived from the expression of genes.

But there is no "IQ" gene and "IQ" is just a human construct that is very flexible and doesn't mean much.

I disagree in spirit. IQ variations are highly heritable (as we know from twin studies), and IQ is arguably the most predictive and significant metric in the science of psychology, strongly associated with everything we typically associate with intelligence, including educational achievement, educational level, income (independent of education), job performance, and lack of crime. But, I agree with you in letter that there is no IQ gene, or at least such a claim would be misleading. It would be less misleading to say there are MANY genes for IQ VARIATIONS. Though it is in my opinion misleading, I think Richard Dawkins would argue in favor of an "IQ gene," and he argued for such a thing well in his book, "Extended Phenotype," as follows:

It follows from the fact that geneticists are always concerned with phenotypic differences that we need not be afraid of postulating genes with indefinitely complex phenotypic effects, and with phenotypic effects that show themselves only in highly complex developmental conditions. Together with Professor John Maynard Smith, I recently took part in a public debate with two radical critics of 'sociobiology”, before an audience of students. At one time in the discussion we were trying to establish that to talk of a gene “for X” is to make no outlandish claim, even where X is a complex, learned behaviour pattern. Maynard Smith reached for a hypothetical example and came up with a “gene for skill in tying shoelaces”. Pandemonium broke loose at this rampant genetic determinism! The air was thick with the unmistakable sound of worst suspicions being gleefully confirmed. Delightedly {23} sceptical cries drowned the quiet and patient explanation of just what a modest claim is being made whenever one postulates a gene for, say, skill in tying shoelaces. Let me explain the point with the aid of an even more radical-sounding yet truly innocuous thought experiment (Dawkins 1981).

Reading is a learned skill of prodigious complexity, but this provides no reason in itself for scepticism about the possible existence of a gene for reading. All we would need in order to establish the existence of a gene for reading is to discover a gene for not reading, say a gene which induced a brain lesion causing specific dyslexia. Such a dyslexic person might be normal and intelligent in all respects except that he could not read. No geneticist woiild be particularly surprised if this type of dyslexia turned out to breed true in some Mendelian fashion. Obviously, in this event, the gene would only exhibit its effect in an environment which included normal education. In a prehistoric environment it might have had no detectable effect, or it might have had some different effect and have been known to cave-dwelling geneticists as, say, a gene for inability to read animal footprints. In our educated environment it would properly be called a gene “for” dyslexia, since dyslexia would be its most salient consequence. Similarly, a gene which caused total blindness would also prevent reading, but it would not usefully be regarded as a gene for not reading. This is simply because preventing reading would not be its most obvious or debilitating phenotypic effect.

Returning to our gene for specific dyslexia, it follows from the ordinary conventions of genetic terminology that the wild-type gene at the same locus, the gene that the rest of the population has in double dose, would properly be called a gene “for reading”. If you object to that, you must also object to our speaking of a gene for tallness in Mendel's peas, because the logic of the terminology is identical in the two cases. In both cases the character of interest is a difference, and in both cases the difference only shows itself in some specified environment. The reason why something so simple as a one gene difference can have such a complex effect as to determine whether or not a person can learn to read, or how good he is at tying shoelaces, is basically as follows. However complex a given state of the world may be, the difference between that state of the world and some alternative state of the world may be caused by something extremely simple.​

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I know you said that before, and I am not challenging it, but I would love to get more information about it, if you happen to have any leads. If I remember correctly, I tried researching it, but I did not succeed finding any confirmation or disconfirmation.

This is because no one has established or provided an indefeasible theory (as in the theory of evolution) that genes determine intelligence.

OK, to clarify, I was asking about the periodic mass killing of intelligent people in China.

 

[untermensche]

IQ variations are highly heritable (as we know from twin studies)...

Twin studies look at the expression of a similar genome.

They say nothing about the passing of intelligence through sexual reproduction.

IQ is arguably the most predictive and significant metric in the science of psychology, strongly associated with everything we typically associate with intelligence, including educational achievement, educational level, income (independent of education), job performance, and lack of crime.

This in no way means that IQ represents what it claims to represent.

It may simply measure obedience which will also be highly associated with all those other things.

 

[ApostateAbe]

I wonder how familiar these IQ researchers are with experimental quantitative genetics and population genetics. If we took a group of geneticists and asked them survey questions about the role that genes play in racial differences in IQ how many of them would argue that it plays a significant or partial role? The researchers in this survey were psychologists. I'm not sure that the average psychologist including experts on intelligence testing are knowledgeable enough of genetics research to give an informed opinion on this subject.

Yeah, the field definitely needs more criticism from and integration with the field of population genetics, in my opinion. Psychologists would be dealing with IQ and heritability on a macro level (heritability analyses via twin studies, racial studies and so on hardly need any knowledge of DNA), but population geneticists would make sense of it, possibly strike it all down, on the molecular level. In the past, such research was deterred due to politics, but in the last few years the research has started to be serious, with some claiming to have found sets of alleles that account for a large part of the variance of IQ (Davies et al, 2011), and another study claiming to use the same alleles to explain part of racial IQ differences (Piffer 2015). I won't claim certainty yet, as appropriate for any new science.

 

[ApostateAbe]

Twin studies look at the expression of a similar genome.

They say nothing about the passing of intelligence through sexual reproduction.

IQ is arguably the most predictive and significant metric in the science of psychology, strongly associated with everything we typically associate with intelligence, including educational achievement, educational level, income (independent of education), job performance, and lack of crime.

This in no way means that IQ represents what it claims to represent.

It may simply measure obedience which will also be highly associated with all those other things.

Sexual reproduction is the copying of genes, so, yeah, I think twin studies really do say a lot about the heritability of intelligence. If identical twins rearead apart tend to be more similar than non-identical twins reared together and MUCH more similar than unrelated children reared together, then there really is no way to explain the phenotypic similarity but through similar genes. IQ represents intelligence, even if intelligence is gained through obedience (I doubt it but I would love to see an argument for it).

 

[untermensche]

Twin studies look at the expression of a similar genome.

They say nothing about the passing of intelligence through sexual reproduction.



This in no way means that IQ represents what it claims to represent.

It may simply measure obedience which will also be highly associated with all those other things.

Sexual reproduction is the copying of genes, so, yeah, I think twin studies really do say a lot about the heritability of intelligence. If identical twins rearead apart tend to be more similar than non-identical twins reared together and MUCH more similar than unrelated children reared together, then there really is no way to explain the phenotypic similarity but through similar genes. IQ represents intelligence, even if intelligence is gained through obedience (I doubt it but I would love to see an argument for it).

Sexual reproduction is the combination of two random haploids.

That is why you can sometimes see two average sized parents have a child over 7 feet tall. That is why Einstein was the product of normal parents.

Just because the parent is tall that does not mean the child will be tall. Just because the parent has a certain "intelligence" does not mean the child will have that intelligence.

All twin studies could possibly look at is the expression of the same genome.

It is no wonder the expression of the same genome yields similar individuals.

But twin studies say nothing about the inheritability of "intelligence" whatever that is.

 

[ApostateAbe]

Sexual reproduction is the copying of genes, so, yeah, I think twin studies really do say a lot about the heritability of intelligence. If identical twins rearead apart tend to be more similar than non-identical twins reared together and MUCH more similar than unrelated children reared together, then there really is no way to explain the phenotypic similarity but through similar genes. IQ represents intelligence, even if intelligence is gained through obedience (I doubt it but I would love to see an argument for it).

Sexual reproduction is the combination of two random haploids.

That is why you can sometimes see two average sized parents have a child over 7 feet tall. That is why Einstein was the product of normal parents.

Just because the parent is tall that does not mean the child will be tall. Just because the parent has a certain "intelligence" does not mean the child will have that intelligence.

All twin studies could possibly look at is the expression of the same genome.

It is no wonder the expression of the same genome yields similar individuals.

But twin studies say nothing about the inheritability of "intelligence" whatever that is.

Each child shares only 50% of his or her gene expressions with each parent and sibling, which would explain such variation, with the exception of identical twins. Identical twins share almost 100% of their gene expressions with each other, which is the reason why they are key to inferring the influence of genetics, especially identical twins reared apart. If one identical is 7 feet tall, then the other identical twin will almost certainly be close to seven feet tall, regardless of the height of each parent. If one identical twin has the measured intelligence of 150, then the other identical twin will almost certainly have a measured intelligence close to 150, even if he or she is raised in an entirely different household. This is significant data, and bizarre ad hoc explanations are not even available. There absolutely can be no other explanation but the strong influence of genetic variations.

 

[J842P]

If one identical twin has the measured intelligence of 150, then the other identical twin will almost certainly have a measured intelligence close to 150, even if he or she is raised in an entirely different household. This is significant data, and bizarre ad hoc explanations are not even available. There absolutely can be no other explanation but the strong influence of genetic variations.

Certainly not! That is a fundamental misunderstanding of the concept of heritability. Every single trait is influenced by environmental factors regardless of heritability. Such a thing is trivial to see. Consider a trait that has high heritability, such as height. Take two identical twins. Raise one twin with a severely protein and calcium deficient diet and the other with as much of these nutrients as they want. Their heights will be very different despite almost perfect heritability. It is better to think of heritability as the propensity to be influenced by selection rather than some number that guarantees a particular outcome regardless of environment.

With very few exceptions, environment always has strong effects on any high-level trait like height, intelligence, etc.

But you are right, twin studies do in fact establish a strong genetic component of IQ as they do with traits like height or arm length.

 

[untermensche]

Sexual reproduction is the combination of two random haploids.

That is why you can sometimes see two average sized parents have a child over 7 feet tall. That is why Einstein was the product of normal parents.

Just because the parent is tall that does not mean the child will be tall. Just because the parent has a certain "intelligence" does not mean the child will have that intelligence.

All twin studies could possibly look at is the expression of the same genome.

It is no wonder the expression of the same genome yields similar individuals.

But twin studies say nothing about the inheritability of "intelligence" whatever that is.

Each child shares only 50% of his or her gene expressions with each parent and sibling, which would explain such variation, with the exception of identical twins. Identical twins share almost 100% of their gene expressions with each other, which is the reason why they are key to inferring the influence of genetics, especially identical twins reared apart. If one identical is 7 feet tall, then the other identical twin will almost certainly be close to seven feet tall, regardless of the height of each parent. If one identical twin has the measured intelligence of 150, then the other identical twin will almost certainly have a measured intelligence close to 150, even if he or she is raised in an entirely different household. This is significant data, and bizarre ad hoc explanations are not even available. There absolutely can be no other explanation but the strong influence of genetic variations.

Twin studies do show that there is a genetic component to "intelligence". But this is not news.

They do not show that "intelligence", whatever that is, is inheritable.

They do not show that "intelligent" parents are more likely to have "intelligent" children.

And they certainly do not show that an IQ test measures "intelligence".

 

[ApostateAbe]

If one identical twin has the measured intelligence of 150, then the other identical twin will almost certainly have a measured intelligence close to 150, even if he or she is raised in an entirely different household. This is significant data, and bizarre ad hoc explanations are not even available. There absolutely can be no other explanation but the strong influence of genetic variations.

Certainly not! That is a fundamental misunderstanding of the concept of heritability. Every single trait is influenced by environmental factors regardless of heritability. Such a thing is trivial to see. Consider a trait that has high heritability, such as height. Take two identical twins. Raise one twin with a severely protein and calcium deficient diet and the other with as much of these nutrients as they want. Their heights will be very different despite almost perfect heritability. It is better to think of heritability as the propensity to be influenced by selection rather than some number that guarantees a particular outcome regardless of environment.

With very few exceptions, environment always has strong effects on any high-level trait like height, intelligence, etc.

But you are right, twin studies do in fact establish a strong genetic component of IQ as they do with traits like height or arm length.

The measure of heritability is a correlation, a measure of how well points on a scatter plot align along the best-fit line, so a high heritability increases the odds that the value of one twin will match the value of the other twin. Maybe you disagree with my somewhat extreme expression, but there is no fundamental misunderstanding.

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Each child shares only 50% of his or her gene expressions with each parent and sibling, which would explain such variation, with the exception of identical twins. Identical twins share almost 100% of their gene expressions with each other, which is the reason why they are key to inferring the influence of genetics, especially identical twins reared apart. If one identical is 7 feet tall, then the other identical twin will almost certainly be close to seven feet tall, regardless of the height of each parent. If one identical twin has the measured intelligence of 150, then the other identical twin will almost certainly have a measured intelligence close to 150, even if he or she is raised in an entirely different household. This is significant data, and bizarre ad hoc explanations are not even available. There absolutely can be no other explanation but the strong influence of genetic variations.

Twin studies do show that there is a genetic component to "intelligence". But this is not news.

They do not show that "intelligence", whatever that is, is inheritable.

They do not show that "intelligent" parents are more likely to have "intelligent" children.

And they certainly do not show that an IQ test measures "intelligence".

I think you need to resolve the seeming contradiction between these two statements:

1. Twin studies do show that there is a genetic component to "intelligence".
2. They do not show that "intelligence", whatever that is, is inheritable.

 

[untermensche]

1. Twin studies do show that there is a genetic component to "intelligence".
2. They do not show that "intelligence", whatever that is, is inheritable.

Inheritable means an "intelligent" parent is more likely to have an "intelligent" child. The genetic component of the "intelligence" of the parent is transferred to the child.

That is not the same thing as saying; "intelligence" is partially due to an expression of genes.

 

[whichphilosophy]

I disagree in spirit. IQ variations are highly heritable (as we know from twin studies), and IQ is arguably the most predictive and significant metric in the science of psychology, strongly associated with everything we typically associate with intelligence, including educational achievement, educational level, income (independent of education), job performance, and lack of crime. But, I agree with you in letter that there is no IQ gene, or at least such a claim would be misleading. It would be less misleading to say there are MANY genes for IQ VARIATIONS. Though it is in my opinion misleading, I think Richard Dawkins would argue in favor of an "IQ gene," and he argued for such a thing well in his book, "Extended Phenotype," as follows:

It follows from the fact that geneticists are always concerned with phenotypic differences that we need not be afraid of postulating genes with indefinitely complex phenotypic effects, and with phenotypic effects that show themselves only in highly complex developmental conditions. Together with Professor John Maynard Smith, I recently took part in a public debate with two radical critics of 'sociobiology”, before an audience of students. At one time in the discussion we were trying to establish that to talk of a gene “for X” is to make no outlandish claim, even where X is a complex, learned behaviour pattern. Maynard Smith reached for a hypothetical example and came up with a “gene for skill in tying shoelaces”. Pandemonium broke loose at this rampant genetic determinism! The air was thick with the unmistakable sound of worst suspicions being gleefully confirmed. Delightedly {23} sceptical cries drowned the quiet and patient explanation of just what a modest claim is being made whenever one postulates a gene for, say, skill in tying shoelaces. Let me explain the point with the aid of an even more radical-sounding yet truly innocuous thought experiment (Dawkins 1981).

Reading is a learned skill of prodigious complexity, but this provides no reason in itself for scepticism about the possible existence of a gene for reading. All we would need in order to establish the existence of a gene for reading is to discover a gene for not reading, say a gene which induced a brain lesion causing specific dyslexia. Such a dyslexic person might be normal and intelligent in all respects except that he could not read. No geneticist woiild be particularly surprised if this type of dyslexia turned out to breed true in some Mendelian fashion. Obviously, in this event, the gene would only exhibit its effect in an environment which included normal education. In a prehistoric environment it might have had no detectable effect, or it might have had some different effect and have been known to cave-dwelling geneticists as, say, a gene for inability to read animal footprints. In our educated environment it would properly be called a gene “for” dyslexia, since dyslexia would be its most salient consequence. Similarly, a gene which caused total blindness would also prevent reading, but it would not usefully be regarded as a gene for not reading. This is simply because preventing reading would not be its most obvious or debilitating phenotypic effect.

Returning to our gene for specific dyslexia, it follows from the ordinary conventions of genetic terminology that the wild-type gene at the same locus, the gene that the rest of the population has in double dose, would properly be called a gene “for reading”. If you object to that, you must also object to our speaking of a gene for tallness in Mendel's peas, because the logic of the terminology is identical in the two cases. In both cases the character of interest is a difference, and in both cases the difference only shows itself in some specified environment. The reason why something so simple as a one gene difference can have such a complex effect as to determine whether or not a person can learn to read, or how good he is at tying shoelaces, is basically as follows. However complex a given state of the world may be, the difference between that state of the world and some alternative state of the world may be caused by something extremely simple.​

- - - Updated - - -

I know you said that before, and I am not challenging it, but I would love to get more information about it, if you happen to have any leads. If I remember correctly, I tried researching it, but I did not succeed finding any confirmation or disconfirmation.

This is because no one has established or provided an indefeasible theory (as in the theory of evolution) that genes determine intelligence.

OK, to clarify, I was asking about the periodic mass killing of intelligent people in China.

Which twin studies are you referring to. Sir Cyril Burt because apart from ordering his secret research to be burnt at his death is work was flawed. His predecessors in Nazi Germany didn't make any headway in this either. Jensen and Rushton tended to agree with Burt but again there is nothing conclusive.
Tests have also been done in parallel with shared environments, fraternal (as well as monozygotic) twins but this remains inconclusive.

 

[ApostateAbe]

1. Twin studies do show that there is a genetic component to "intelligence".
2. They do not show that "intelligence", whatever that is, is inheritable.

Inheritable means an "intelligent" parent is more likely to have an "intelligent" child. The genetic component of the "intelligence" of the parent is transferred to the child.

That is not the same thing as saying; "intelligence" is partially due to an expression of genes.

That doesn't seem to resolve the seeming contradiction, but it only expresses the contradiction more plainly.

 

[ApostateAbe]

I disagree in spirit. IQ variations are highly heritable (as we know from twin studies), and IQ is arguably the most predictive and significant metric in the science of psychology, strongly associated with everything we typically associate with intelligence, including educational achievement, educational level, income (independent of education), job performance, and lack of crime. But, I agree with you in letter that there is no IQ gene, or at least such a claim would be misleading. It would be less misleading to say there are MANY genes for IQ VARIATIONS. Though it is in my opinion misleading, I think Richard Dawkins would argue in favor of an "IQ gene," and he argued for such a thing well in his book, "Extended Phenotype," as follows:

It follows from the fact that geneticists are always concerned with phenotypic differences that we need not be afraid of postulating genes with indefinitely complex phenotypic effects, and with phenotypic effects that show themselves only in highly complex developmental conditions. Together with Professor John Maynard Smith, I recently took part in a public debate with two radical critics of 'sociobiology”, before an audience of students. At one time in the discussion we were trying to establish that to talk of a gene “for X” is to make no outlandish claim, even where X is a complex, learned behaviour pattern. Maynard Smith reached for a hypothetical example and came up with a “gene for skill in tying shoelaces”. Pandemonium broke loose at this rampant genetic determinism! The air was thick with the unmistakable sound of worst suspicions being gleefully confirmed. Delightedly {23} sceptical cries drowned the quiet and patient explanation of just what a modest claim is being made whenever one postulates a gene for, say, skill in tying shoelaces. Let me explain the point with the aid of an even more radical-sounding yet truly innocuous thought experiment (Dawkins 1981).

Reading is a learned skill of prodigious complexity, but this provides no reason in itself for scepticism about the possible existence of a gene for reading. All we would need in order to establish the existence of a gene for reading is to discover a gene for not reading, say a gene which induced a brain lesion causing specific dyslexia. Such a dyslexic person might be normal and intelligent in all respects except that he could not read. No geneticist woiild be particularly surprised if this type of dyslexia turned out to breed true in some Mendelian fashion. Obviously, in this event, the gene would only exhibit its effect in an environment which included normal education. In a prehistoric environment it might have had no detectable effect, or it might have had some different effect and have been known to cave-dwelling geneticists as, say, a gene for inability to read animal footprints. In our educated environment it would properly be called a gene “for” dyslexia, since dyslexia would be its most salient consequence. Similarly, a gene which caused total blindness would also prevent reading, but it would not usefully be regarded as a gene for not reading. This is simply because preventing reading would not be its most obvious or debilitating phenotypic effect.

Returning to our gene for specific dyslexia, it follows from the ordinary conventions of genetic terminology that the wild-type gene at the same locus, the gene that the rest of the population has in double dose, would properly be called a gene “for reading”. If you object to that, you must also object to our speaking of a gene for tallness in Mendel's peas, because the logic of the terminology is identical in the two cases. In both cases the character of interest is a difference, and in both cases the difference only shows itself in some specified environment. The reason why something so simple as a one gene difference can have such a complex effect as to determine whether or not a person can learn to read, or how good he is at tying shoelaces, is basically as follows. However complex a given state of the world may be, the difference between that state of the world and some alternative state of the world may be caused by something extremely simple.​

- - - Updated - - -

I know you said that before, and I am not challenging it, but I would love to get more information about it, if you happen to have any leads. If I remember correctly, I tried researching it, but I did not succeed finding any confirmation or disconfirmation.

This is because no one has established or provided an indefeasible theory (as in the theory of evolution) that genes determine intelligence.

OK, to clarify, I was asking about the periodic mass killing of intelligent people in China.

Which twin studies are you referring to. Sir Cyril Burt because apart from ordering his secret research to be burnt at his death is work was flawed. His predecessors in Nazi Germany didn't make any headway in this either. Jensen and Rushton tended to agree with Burt but again there is nothing conclusive.
Tests have also been done in parallel with shared environments, fraternal (as well as monozygotic) twins but this remains inconclusive.

It turns out that, in spite of the denunciation of Cyril Burt, he was correct all along. I recommend the book, The Burt Affair, for an overview. His estimate of the heritability of IQ (h²=0.7) was validated by a large number of studies of every decade afterward, and it is now established fact. This table, from the book of the intelligence researcher Richard Nisbett titled, Intelligence and How to Get It: Why Schools and Cultures Count, 2010, contains the results of a meta-analysis of 212 heritability studies, and you can review the abstract here: http://www.nature.com/nature/journal/v388/n6641/full/388468a0.html

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[untermensche]

Inheritable means an "intelligent" parent is more likely to have an "intelligent" child. The genetic component of the "intelligence" of the parent is transferred to the child.

That is not the same thing as saying; "intelligence" is partially due to an expression of genes.

That doesn't seem to resolve the seeming contradiction, but it only expresses the contradiction more plainly.

There is no contradiction.

Intelligence is partially due to the expression of genes.

But the genes involved are a random combination from both parents, not a complete copy of either parent.

So the "intelligence" of the offspring is distinct from the "intelligence" of either parent.

Just like many children look nothing like either parent, because the child is not a copy it is a random combination.