i wanna create a faq page of genes that affect behavior, intelligence, etc., that vary in frequency between different populations or the sexes.** i’m tired of having to look up this stuff whenever i want to make a comment somewhere! i thought it might make a good resource for others, too. (if there’s one out there that already exists, lemme know!)
what i’d like to include are:
1) genes that affect behavior, intelligence, etc., that vary in frequency between different populations or the sexes;
2) genes that affect behavior, intelligence, etc., but that we have no frequency info for yet.
here’s what i’ve got so far (off the top of my head):
1)
– MAO-A gene – the “warrior gene”
– DRD4
– DRD2? (i can’t remember)
– MCPH1
2)
– VMAT2 – the “god gene”
– oxytocin- and vasopressin-related genes (whatever the heck they are)
any other suggestions? links to sources would be helpful, but not necessary. i can look stuff up myself. thnx! (^_^)
**edit: i’m talking about alleles, of course. genes, alleles — you know what i mean! (~_^)
(note: comments do not require an email.)
hbd chick 
FOXP2 is important from an evolutionary perspective, but mutations are relatively rare (mainly because they tend to have severe deleterious consequences on language-speaking ability).
The role of genes is vastly over rated.
It needs to always be remembered that genes don’t code for a phenotype, genes code for a process to make a phenotype. That process can’t happen without interaction with the environment, that interaction happens via stochastic resonance, i.e. at the level of noise.
99.9999%+ of that noise-mediated stochastic resonance happens in utero when the individual goes from a single cell to 10^11.
If you want a list of genes for intelligence, I don’t think there is one. That isn’t how “intelligence” occurs. Most of the standard work on IQ and intelligence is highly flawed, so flawed as to be useless. The major flaw is that there isn’t such a thing as “g” that can be measured with IQ tests.
http://cscs.umich.edu/~crshalizi/weblog/523.html
Look especially at note 2. The idea that “g” can be measured with IQ tests is not even wrong, it is under specified. If you have k tests, that gives you k individual factors. If “g” is a linear combination of those independent weighting factors, you have k+1 variables with only k equations. It is indeterminant. If the factors are non-linear (as they most certainly must be), the indeterminacy is even worse.
There is a link to Peter Schonemann webpage. He is passed away now, but there is a lot of good papers on his webpage.
There have been some gigantic whole genome scans for autism, using multi-thousand cohorts. They have found that no single gene contributes more than a few percent other than the multiple cases where single or few gene CNVs cause autism. The CNV associated autism is usually simplex and sporadic, it does not run in families. The genetics of the familial type of autism is completely intractable.
Like the idea of a reference list of such genes. Would also be a good wikipedia entry.
daedalus2u: your gene-denialism and your intelligence-denialism are both baseless.
Nobody seriously denies that height is influenced strongly by genes, but scientists have still not pinpointed the actual genes involved. Likewise it means little that we have not yet found particular intelligence genes. Probably there are interaction effects among many genes.
“Most of the standard work on IQ and intelligence is highly flawed, so flawed as to be useless. The major flaw is that there isn’t such a thing as “g” that can be measured with IQ tests.”
You can ignore this and everything else this ignoramus has to say.
The association of APOE and Alzheimers is well established. Do not ignore the rare variants that cause retardation: PKU, fragile X, etc.
I don’t do FA, therefore I can’t defend g or apprehend criticisms of g. So my beliefs don’t really lean on g. It doesn’t seem to me that my stance would change substantially if I were to become confident in g.
> 99.9999%+ of that noise-mediated stochastic resonance happens in utero when the individual goes from a single cell to 10^11.
So basically you’re asserting that there’s no such thing as additive genetic variance; it’s really gestational G x E variance – ? So you probably think high-IQ mothers have superior gestational E and this causes inheritance of intelligence? Nice try – that’s not easy to totally dismiss, but it seems unlikely.
These would have to be some kind of chemical or electrical, etc factors evenly distributed to each twin, in the case of the facial structure of identical twins – since the resulting facial form is the same for each twin.
In any case, why do you treat it as fact when clearly it is hypothetical?
Physiology is tens of thousands of non-linear coupled parameters. Physiology exhibits the butterfly effect. You can have identical twins that are discordant for anencephaly. Intelligence is a subtle effect that is hard to measure and which is influenced by so many things, prenatal and postnatal.
We aren’t talking about facial features which have a characteristic length of cm, but of neurological features which have a characteristic length of microns. Facial features are mostly fixed by bone structure which is mostly fixed over the lifespan.
Neuroanatomy changes on the length scales that are important, it has to or learning could never happen.
Not a single word here from daedalus2u shows that genes are unimportant or that intelligence is unimportant.
Here they looked at 1,333,653 individuals with a GWA and:
“we identified common variants that account for approximately 10% of phenotypic variation. Although larger than predicted by some models 26, this figure suggests that GWA studies, as currently implemented, will not explain a majority of the estimated 80% contribution of genetic factors to variation in height.”
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2955183/
If they can only find a genetic source for 10% of the variation, maybe the rest of the variation isn’t genetic? Revising the “estimated 80% contribution of genetic factors” should be a pretty high priority. What do they trust, their “estimated 80% contribution” or their lying genetic data?
Height is known to be a sum of the length of various bones, the diameter of the skull, the thickness of t scalp, the amount of hair. Are there separate genes that control the length of individual bones? Is there a femur length gene? A skull thickness gene? A “big hair” gene?
What determines adult height is the process of development. Development is a process. Claiming it is all due to genes is hopelessly simplistic and wrong. Height is pretty simple to measure; intelligence is extremely difficult to measure.
People have looked for genes for intelligence and have not found them. People without an agenda to find genes for intelligence now appreciate that what ever “intelligence” is (it is poorly defined), it is a lot more complicated than genes. The whole idea of intelligence tests is flawed. There are individuals who have scores as much as 70 percentile points different on different intelligence tests. How can two measurements, supposedly of “the same thing” be different by 70 percentile points? They can’t both be measuring “the same thing”.
http://www.ncbi.nlm.nih.gov/pubmed/17680932
Intelligence, like height is a property of a phenotype, not a genotype. Genes don’t make a brain that is more or less intelligent, genes make a process to make a brain via development given the constraints of the environment. With insufficient nutrition, the genes will do the best they can to make a good enough brain, but the genes are not magic. With insufficient environmental stimulation, the same thing. Exposure to toxins like lead cause a brain that is less intelligent. Exposure to traumatic stress does the same thing.
During brain development there are trade-offs. It takes brain volume to do neuronal computations. Those computations are needed for things like sensory processing. If you want good vision, you have to have a visual cortex that can decode the signals from your retinas. A good visual cortex takes up volume that can’t be used for something else. Good hearing takes up space too, so does a good sense of smell, and everything else that the brain needs to do.
So far there isn’t any good data that there is a strong genetic basis for intelligence. There is a strong belief by those who make and score intelligence tests (which happen to strongly favor those who developed in the culture that produced those tests and which was used to scale them) but there isn’t any data.
You haven’t addressed the issues raised in the link. The idea that something like “g” can be measured with tests is wrong. The idea cannot be correct because the system is under specified. There are infinitely many values of “g” that can be obtained from the same data.
You are not talking about science when you talk about something you call “intelligence” when you “measure” it with tests which are under specified.
Most people who talk about the genetics of intelligence are racists who attribute the differences in average intelligence between different races to one thing and one thing only, the genetic inferiority of people who are not like them.
Even if that was correct, there is nothing that can be done about genetics. We know a great deal about how to improve intelligence through non-genetic interventions. We know that better prenatal care, prenatal vitamins, better education, less poverty, better preschools, better kindergartens, better teachers, better grade schools, better high schools, better universities all improve intelligence scores on standardized tests.
Why do the “genetics of intelligence” crowd never talk about what can actually be done that would actually improve intelligence? Simple, because they are not interested in improving intelligence, they are racists and are only interested in justifying their racism.
“Simple, because they are not interested in improving intelligence”
The intelligence in my country was fine as it was. It didn’t need improving. Improving intelligence is only an issue because of the importing of millions of people with lower average intelligence and the subsequent slow decay as the combined population can no longer maintain the same per capita GDP.
@d2u – “Why do the ‘genetics of intelligence’ crowd never talk about what can actually be done that would actually improve intelligence?”
they do. but very few ever listen.
@d2u – “Why do the ‘genetics of intelligence’ crowd never talk about what can actually be done that would actually improve intelligence? Simple, because they are not interested in improving intelligence, they are racists and are only interested in justifying their racism.”
around here you’re allowed to call folks racists ONCE if that is genuinely your opinion.
don’t do it again. repetitive use of the term will just indicate to me that you’re trying to shut down the conversation by intimidating people.
People have called me a gene denier and have told people to not listen to anything I have to say. They have done that instead of answering how g or IQ can be measured.
What about the Flynn effect?
http://en.wikipedia.org/wiki/Flynn_effect
We know the genetics of those populations didn’t change, yet their intelligence changed a gigantic amount, more than the difference between races.
Presumably there could have been gene flow from the “smarter” races to the “dumber” ones, but where did the “smarter” race get their even “smarter” genes? From aliens?
An excellent blog that does address some of the actual problems with the research on intelligence (although that is not the major focus of his blog) is here.
http://scienceblogs.com/gregladen/2010/08/persistent_ethnic_differences.php#more
People who want to use intelligence tests for something, need to demonstrate that those tests are valid for what they are trying to do with them. They never have, and then continue to hand wave that they are valid when they cannot be shown to be valid.
This particular blog links to a paper that demonstrates that the history of intelligence testing is absolutely filled with studies that are woefully under powered. Under powered by orders of magnitude.
I don’t have time to point out all sd2’s straw men and errors or to answer his ignorant rhetorical questions. It’s enough to say that the preponderance of a century of intelligence research since Spearman, and almost as long a period of heritability studies (using twins usually) is against him. Start with the wikipedia page for “general factor of intelligence”.
@d2u – “We know the genetics of those populations didn’t change….”
do we?
Yes, we do. The gene pool can’t change that much in a few years.
Jim, twins also share an in utero enviornment, where they grow from a single cell to 10^11 cells. The heritability of intelligence in twins is due to both shared genes and a shared in utero environment.
There is another human characteristic that is extremely highly heritable, that of language. Essentially all children speak the language of their parents. The heritability of language is much higher than that of height or intelligence. So what are the genes for speaking French, English, German, Japanese?
I appreciate that children can’t speak their native language at birth, but neither can children at birth take intelligence tests. Children develop the ability to speak long before they develop the ability to take intelligence tests. If ability to do well on intelligence tests is mostly genetic, the ability to do well at speaking a language must be even more genetic because it comes earlier and without any special training at all. Children spontaneously develop the ability to speak the language spoken by their parents.
Maybe the people looking (so far in vain) for the genes that produce the heritability of intelligence should focus first on the genes that produce the heritability of language. They should be a lot easier to find because language is a lot easier to measure and there are only a limited number of them.
There is probably some overlap between genes for language and genes for intelligence because many populations that speak one language also have a skewed performance on intelligence tests.
Jim, yes, and the preponderance of research said that ulcers were caused by stress, until it didn’t.
Before then, the proponderance of research said hat mental illness was caused by posession by demons, until it didn’t.
Address the issue of “g” being indeterminant. Address the issue of there being no ability to actually find genes that produce intelligence.
hbd chick, the Flynn effect has been observed in many places. If intelligence is due mostly to genetics, how can the genetics in all of those different places have changed in that single direction so rapidly and so universally?
@d2u – “If intelligence is due mostly to genetics….”
i never said that it was.
@d2u – “The gene pool can’t change that much in a few years.”
but we’re not talking about a few years, we’re talking about a couple of generations. and, sure, the gene pool can change in a couple of generations. imagine the culling effects of wwi and wwii — two generations in a row of prolly not the brightest getting killed off (as the brightest would’ve managed to stay out of the fighting like they usually do). two, ginormous cullings of dullards.
i’m not saying that this definitely happened. i’m just saying that alterations of the frequencies of certain alleles within populations can happen rather rapidly.
@d2u – “Children develop the ability to speak long before they develop the ability to take intelligence tests.”
not true.
@d2u – “the proponderance of research said that mental illness was caused by posession by demons….”
that wasn’t research. that was mythology.
There are genetic differences in all sorts of physical characteristics between ethnic groups as shown in every olympics.
The balance of probablity is with their being differences in mental capabilities too.
People (who are honest) who deal all day with people with widely differing origins see it all day. It’s just a question of proving it. If science wasn’t constrained by the new heliocentricity rule then it would be proved every which way very rapidly.
Once proved i doubt there’d be a single intelligence trait but a suite of them that combine in different ways.
IQ may not relate to intelligence in the common sense of the word. One obvious difference you notice on the ground is you can have two people who function at the same level at various short-term tasks but one of them is completely incapable of planning even one day ahead. Obviously that would correlate with 90% of what we’d think of as intelligence but is not quite the same.
“Jim, twins also share an in utero enviornment, where they grow from a single cell to 10^11 cells. The heritability of intelligence in twins is due to both shared genes and a shared in utero environment. ”
This is just one example of your ignorance and ill will.
Heritability studies compare identical (MZ) and fraternal (DZ) twins — MZ and DZ twins share the same uterus, but only MZ have the same genes.
Are you saying there is no effect of a shared in utero environment?
Who is being ignorant? We know that if a mother drinks a pint of burbon every day through her pregnancy, and is carrying twins, both twins will be affected, whether they are MZ or DZ twins or not.
> If they can only find a genetic source for 10% of the variation, maybe the rest of the variation isn’t genetic?
‘Rare’ alleles (scare quotes because not all of em are terribly ‘rare’). GWAS isn’t the end of the game.
> If intelligence is due mostly to genetics, how can the genetics in all of those different places have changed in that single direction so rapidly and so universally?
Heritability is defined per pop and per moment in time. It’s explicitly recognized that it can change. It’s pretty clear that the heritability of height must have increased substantially in the last 200 years in agricultural peoples: used to be some were much better fed than others, so some got closer to the full height corresponding to their genotype, than others. No more is this the case; all are well fed. So the phenotypic variance and environmental variance have declined, while the genetic variance remained the same. Thus, (genetic variance) / (height variance) = hertability of height, probably increased quite a bit.
> the Flynn effect has been observed in many places. If intelligence is due mostly to genetics, how can the genetics in all of those different places have changed in that single direction so rapidly and so universally?
Variance in a quantitative trait is determined to X extent by additive genetic variance, to Y extent by environment, to Z extent by G x E factors, etc – but each and all of these figures X Y and Z etc can change at any time for any reason.
Wikipedia: “In addition, heritability can change without any genetic change occurring. […] heritability is specific to a particular population in a particular environment.”
RS, I agree that “heredity” can change rapidly. The heredity of first language changes in one generation.
The OP was about genes for intelligence, not just heredity for intelligence.
Umm, hbd, they thought they were doing research, they just never learned the most important principle of science. “The first principle is that you not fool yourself and you are the easiest person to fool” (Feynman). ;)
Umm, hbd, a 20+ year old citation to a lay article that also says:
“Moreover, several studies have shown that tests that try to predict intelligence can have a self-fulfilling effect; the simple expectation that a child will do well or poorly will lead parents and teachers to treat the child in ways that may make the prediction come true.”
is not persuasive to me.
The abstract of this paper some years later says the Fagan test doesn’t really work.
http://onlinelibrary.wiley.com/doi/10.1348/026151003322535237/abstract
Autism is very difficult to diagnose in the first year of age.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923050/?tool=pubmed
If autism is difficult to diagnose, what basis is there for thinking that IQ would be easy to measure?
If the Ravans and the WISC can be different by more than 70 percentile points on the same individual, what are they actually be supposed to be measuring?
One of the reasons my comments are kind of stilted and come in bursts is that your site is blocked where I am and I can only access it in 10 minute intervals unless I go off site. Sorry for that. I would like to be more contemplative and nuanced but trying to get stuff in in 10 minutes makes me kind of rushed.
Address the Flynn effect.
The issue of “g” being indeterminant has been known since at least 1928.
http://www.sciencemag.org/content/67/1731/244
The indeterminacy of “g” has been willfully covered up by journal editors.
Click to access 86.pdf
I have never published anything on intelligence except in blog comments. I have nothing in this fight except the desire to live in the reality based community. I think that the reality based community is the best place to live and I welcome anyone who wants to live with me there.
I do subscribe to human biological diversity in all its forms. Intellectual diversity is the most important and is the one that some people find the most threatening. That is why intellectual diversity, in particular “Theory of Mind” diversity, triggers xenophobia. I have written a blog about it; why it happens and how to avoid it.
I am perfectly willing to be shown to be wrong. Show me how “g” is not indeterminant. Don’t simply assert it and expect me to agree. I understand that many people want to believe that IQ tests can measure “g” uniquely. I understand that many people do believe that IQ tests can measure “g” uniquely. Show me the mathematical analysis that demonstrates that there is a chain of facts and logic that proves it and not just a chain of beliefs. I know there is a chain of belief. A chain of belief is not good enough for me.
Greying Wanderer, I agree with you that there is a great deal of diversity, a great many different people with all sorts of different abilities and that they all end up being due to differences in physiology.
Will Rogers said: “I Never Met a Man I Didn’t Like”, my philosophy is that I have never met someone I can’t learn something from.
Some people are asserting that it is “proven” and there is only a single “intelligence”, and it is “g” and that IQ tests measure it and differences in it are mostly genetic. Are you agreeing with me in saying that they are wrong and such a thing has not been “proven”?
If something hasn’t been “proven”, my default is to say “I don’t know” and to keep an open mind, not to latch onto ideas which have already been proven false. The idea that “g” can be determined by IQ tests has been shown to my satisfaction to be false.
Physiology is really complicated, a lot more complicated than most people realize. It is gigantically more complicated than most gene-researchers realize. Genes only comprise a few percent of the genome. What the rest does is mostly unknown. Presumably some of it is doing something because a lot of it has been conserved, since fish.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC526512/?tool=pubmed
“Most people who talk about the genetics of intelligence are racists who attribute the differences in average intelligence between different races to one thing and one thing only, the genetic inferiority of people who are not like them.”
“If something hasn’t been “proven”, my default is to say “I don’t know” and to keep an open mind,”
Heliocentricity.
There are genetic physical differences made blindingly obvious at every olympics.
The balance of probability is that there will be mental differences also.
Some people want to shut that down by screaming “racist!”
It’s the new heliocentricity heresy and not only is it irritating and harmful to all social policy it’s also completely pointless as the Chinese, Japanese and Koreans will carry on the research anyway.
@d2u – “Umm, hbd, they thought they were doing research, they just never learned the most important principle of science.”
just ’cause someone thinks they’re doing research — and by research i understand you to mean scientific research, i.e. using the scientific method — doesn’t mean they’re actually doing research.
besides, i don’t think peoples who came up with mythologies ever thought they were doing research. they were just trying to come up with explanations for what they saw in the world — and mostly they used the first sh*t that came off the tops of their heads!
@d2u – “The abstract of this paper some years later says the Fagan test doesn’t really work.”
well, the paper you referenced only followed up on the kids to age 2, whereas this study (paper co-authored by fagan) followed up on the kids to age 3 and it did find the fagan test to be predictive.
perhaps the jury is still out on this one, but i wouldn’t dismiss the idea completely as you have. keep an open mind!
@d2u – “Autism is very difficult to diagnose in the first year of age.”
or maybe not. again, maybe you should keep an open mind about these things.
i don’t want to get into a tit-for-tat discussion with you about this ’cause, frankly, i think it will waste both of our times. you think that the role of genes in behavior|intelligence is very low to nil (amiright?) — i think the role of genes (i actually mean the whole of our genomes, btw) is greater than that BUT IS NOT THE ONLY THING. clearly — CLEARLY — environment matters. more in some instances than others. i have never said otherwise.
the reason i want to make a list of the genes that (and note my wording in my original post) AFFECT (i.e. not determine!) behavior|intelligence is that there are too many people out there who deny them a role at all (maybe you’re one of them, i’m not sure). that is just obviously wrong — and i mean to do something about it. (~_^)
@d2u – “One of the reasons my comments are kind of stilted and come in bursts is that your site is blocked where I am and I can only access it in 10 minute intervals unless I go off site. Sorry for that.”
no problem! no apology necessary.
that s*cks that my lil ol’ blog is blocked by you! i don’t know whether to be annoyed … or to feel proud (if it’s due to the content, that is). (~_^)
> RS, I agree that “heredity” can change rapidly. The heredity of first language changes in one generation. The OP was about genes for intelligence, not just heredity for intelligence.
The heritability of native language hasn’t changed. It has always been zero, since native tongue is totally determined by environment.
(Although the voices of human races are somewhat distinguishable, even among native speakers of a given language. How the differences are properly described, I’m not sure. I know how to give a ‘reductionist’ acount of an image, but not so much when it comes to sound.)
Hbdchick: high-priority CONTRABAND in 119/122 polities surveyed. Apparently licit in North Korea.
THEY don’t want YOU to know…
@rs – “Apparently licit in North Korea.”
ha! (^_^)
hbd, you are right, they had an idea, they thought it was all sciencey, but it wasn’t. Now we know it was a myth. That is how science progresses. People have an idea, they make a hypothesis, then we check the idea against reality using experiments and math and stuff. If the idea fails, like if we can’t find the genes that we think are there, then we have to abandon our idea and try something else.
Being able to formulate your ideas in a manner that can be falsified is one of the most important characteristics of doing science. When people don’t do that, they can come up with ideas that are said to be “not even wrong”. If you have an idea that you can show is wrong, then you have made progress, you have one less wrong idea. If you formulate your ideas such that they can’t be shown to be wrong, then you can’t make progress.
The ability to question your most fundamental principles is extremely important. It is probably the most important aspect to being a real scientist. Real scientists want to be shown to be in error when they are. Feynman has an excellent example in Millikan’s oil drop experiment.
http://en.wikipedia.org/wiki/Cargo_cult_science
Do you think Millikan was pleased when people published wrong values of the charge on the electron because they didn’t want to publish something that was too far away from the value Millikan came up with? No, Millikan was too good an experimentalist for that. He wanted accuracy and precision above all else. I think he would have been ripshit.
Millikan never put his feelings above the accuracy of his data. Millikan didn’t believe that Einstein’s photoelectric effect was correct. Millikan was one of the last holdouts in physics. Essentially everyone else had been convinced many years before Millikan was convinced. All the others were convinced by the data that Millikan himself had generated and published. They knew that Millikan didn’t like the photoelectric effect that his data fitted so exquisitely well.
About the role of genes in intelligence, I am not sure. I think that most of it is epigenetics from in utero stuff. There can’t be “genes for intelligence”. Intelligence is a property of a phenotype, genes don’t make a phenotype, genes make a process to make a phenotype. The most important properties of the brain, plasticity, ability to form memories and stuff are things that everyone has. It isn’t clear how or what physiology could be changed in a brain to make it more intelligent. Mostly I think it is a trade-off, more ability at one thing for less ability at something else. I talk a lot about a trade off of “theory of mind” for “theory of reality” on my blog. I think that is the trade-off along the autism spectrum. Science is a “theory of reality” type of cognition, social stuff is a “theory of mind” type of cognition. The brain is limited in size, there are limited neuronal resources, what is optimized for one thing can’t be optimized for something else. That fundamental optimization occurs in utero when the major structures are formed. There is lots of plasticity and there can be changes later, but there are limits.
Evolution is a trade-off. Every human needs neuroanatomy to decode sensory data, vision, hearing, smell, taste, touch. Neuroanatomy to move different parts of the body, voluntary and involuntary. Neuroanatomy to communicate with, to think about things, to remember things. The brain is limited in size. Neuroanatomy optimized for one thing can’t be optimum for something else. In the wild, being smart would be useless if you couldn’t move, see or talk. If your ANS couldn’t control your bowels or vasculature or immune system you would die too. If your brain is so big that you kill your mother being born, that doesn’t work either.
I think one of the great innovations of humans is dispersion in cognitive abilities. I think this had to happen because the maternal pelvis is limited in size and genes driving brain growth evolved faster than genes driving maternal pelvis size. Rather than simply having a gigantic brain that can do everything, humans specialized so some had good vision, some had good dexterity, some had good communication and some had good tool making and tool using skills. A tribe that had experts in multiple different areas did better than the tribe with every member being average.
Neanderthal females had a larger pelvis and so could accommodate a larger brain at birth so the specialization that modern humans developed wasn’t needed (my hypothesis). The functionality of a neural network is highly non-linear (it is approximately exponential). An individual with a visual cortex twice the average size has much better vision than two average individuals. Twice the motor cortex gives much better manual dexterity. Humans have incredible manual dexterity. It takes monkeys a couple of years to learn how to break nuts using one rock as an anvil and one as a hammer. Humans can do that in a few minutes. Flaking stone tools takes considerable manual dexterity too. Human have dispersion in their abilities. That is why division of labor works. If you work at something, your brain’s plasticity makes you an expert at it.
Intelligence tests don’t test for things like manual dexterity or sensory acuity, things that we know were very important in recent human evolutionary time and will take up brain volume. My hypothesis is that essentially any human genotype (as long as there aren’t serious flaws) can support a very broad range of phenotypes depending on the trajectory of development. A tribe needed that diversity among its limited gene pool. Tweaking the proliferation of neurons during the first trimester will have large effects on the adult brain. People with autism have a larger number of neurons arranged in a larger number of minicolums that are smaller. The number of minicolums is fixed at 8 weeks gestation.
The whole concept of “g” is very highly flawed. So flawed as to be useless and even harmful. If the proponents of “g” could demonstrate that the concept is not indeterminant it would be something to consider, but they can’t.
It is work, they block many blogs. Some (such as yours) they ration access to in 10 minute snippets. Better than nothing. ;)
Grey, there are differences which you think are due to genetics which are obvious every Olympics. Are those differences actually due to genetics? Is there, you know, actual data that shows that those differences are actually due to genetics and not due to training or nutrition, or steroids or Epo or growth hormone?
Without GWAs on athletes and non-athletes it is kind of hard (for me) to tell if the blindingly obvious differences are due to genetics and not due to a zillion hours of training, I admit that it is a good hypothesis that some of the differences between the gold medal winners and those who stay at home on the couch watching the Olympics on TV could be due to genetics. I know with zero doubt that there are gigantic differences in the amount of training between the couch potatoes and the gold medal winners. Probably the training difference is at least tens of thousands of hours. I also know that there is essentially zero chance that any genotype can achieve gold metal status at the Olympics without a zillion hours of training.
Could you give me a hint of the method you used to determine that the differences are due to genetics and not training? To me, you are just an anonymous pseudonym on the internet. You do have data to support your hypothesis, don’t you? It isn’t just a belief?
In any case, what does that have to do with genes for intelligence?
You want to make the analogy that because you see differences between athletes and non-athletes which you assume (without data) are due to genetics (and not training which you know is important and highly divergent), that you want to assume that mental differences between individuals? Races? Are due to genetics also? Also without data? Using testing procedures that are known to have bias, and which cannot be shown to be non-indeterminant?
And you criticize my scientific rigor? Srsly?
Making arguments from probability? Srsly? You want to set social policy based on arguments from probability?
I don’t want to shut you down by shouting racist. I want you to show me the data, and if you can’t, I want you to admit to yourself that you can’t so that you can realize you are wrong and so that you change your beliefs.
@d2u – “hbd, you are right, they had an idea, they thought it was all sciencey, but it wasn’t.”
no. nobody on this planet who believes|d that mental illness is caused by posession by demons thought what they are|were doing is|was sciencey!
*facepalm*
Yes they did, they just had a different idea of what “science” was.
What about Scientologists?
@d2u – “they just had a different idea of what ‘science’ was.”
exactly.
@d2u – “It isn’t clear how or what physiology could be changed in a brain to make it more intelligent.”
you haven’t read cochran, hardy, and harpending, have you?
“Without GWAs on athletes and non-athletes it is kind of hard (for me) to tell if the blindingly obvious differences are due to genetics and not due to a zillion hours of training”
East Africans + training = long distance gold medals
West African + training = sprint gold medals
Blindingly obvious to anyone who isn’t deliberately trying to confuse the issue.
“I don’t want to shut you down by shouting racist.”
Yes you do. You tried it upthread but no-one took any notice so now you’re gonna try and bore everyone into submission.
“I want you to show me the data”
No you don’t. You want to PREVENT the data.
hbd ok, I read it. There is nothing that conflicts with what I have been saying. I find it interesting that the statement is made that the Ashkenazi Jews tend to have somewhat poorer visuospatial abilities. A smaller visual cortex would lead to poorer visual abilities and would leave more skull volume for neuroanatomy to do other things.
There are differences in human mental abilities. Some of those differences can (very rarely) be associated with single gene variants. It is like many diseases. Some can (very rarely) be associated with single gene variants. Does that show that all disease is caused by genetics? No, it does not.
In the early part of the 20th century, there were a great many Jewish boxers.
http://www.myjewishlearning.com/culture/2/Sports/Sports_and_Judaism/America/Boxing.shtml
Did those Jewish boxers have “good boxing genes”? No, they didn’t, no more than did all the other ethnic groups, English, Irish, Blacks, Italians who were at one time the dominant ethnicity in boxing due to the absence of other opportunities due to xenophobia. At the time there were all sorts of racist just so stories that explained why each ethnic group came to dominate boxing.
A good paper that discusses some of the flaws in how twin studies are used to falsely impute a high heritability to behavioral traits is here.
Click to access Ehrlich-Feldman.pdf
A number of quotes are pretty informative.
“Suppose that a study shows that identical twins, separated at birth, nonetheless show a high correlation of personality type—both members of twin pairs tend to be either introverted or extraverted. This is interpreted as a high heritability of introversion and extraversion. What really is heavily influenced by genetics, however, could be height, and tall people in that society (as in many societies) may be better treated by their peers and thus more likely to become extraverted.”
“This acceptance is entirely due to the widespread acceptance of the statistical methodology that leads to the reporting of broad-sense heritability and its misinterpretation as an index of genetic causality, not to any neurogenetic advances that have tied human behavioral differences to variation in DNA.”
“Our point is that the assumptions used to build the statistical models that produce these estimates do not permit us to infer from such heritability estimates the actual extent of “genetic influences” on IQ. Further,these estimates do not inform potential strategies for determining the nature of such genetic influences, if they exist. Applications of broad-sense heritability to predictive situations are, we repeat, biologically and statistically erroneous (Feldman and Lewontin 1975). Evolutionary psychologists and behavioral geneticists persist in confounding a technically defined statistic named “heritability” with the colloquial use of that term. The concept of overall heritability should be restricted in its employment to plant and animal breeding, where it can be better measured and the results put to some practical use—such as in applying selection to increase the rate of growth of beef cattle or the weight of swine.”
One of the comments following the paper (by Bernardo Dubrovsky) is also quite good.
“Moreover, linear additive models in the absence of a theory of interaction are invalid (Lewontin 2000). That both genes and environment produce a given outcome is a truism, but we are seriously mistaken when we presume that we can best express this principle by assigning percentages and stating, for example, that behaviour A is 40% genetic and 60% environmental. Such reductionist expressions go beyond simple mistakes to enter the domain of the meaningless. Genetics and environment do interact to build a totality, but we need to understand why the resulting wholes are irreducible to separate components.”
This is the fundamental problem of ascribing a certain percentage to environment and genetics. They are coupled with non-linear coupling. It makes no sense to use a percentage which is a linear model when we know it isn’t linear. Non-linear coupled systems exhibit the butterfly effect. A hurricane may absolutely depend on the flap of a specific butterfly wing in a certain place at a certain time. The same hurricane also absolutely depends on millions of other events also happening in certain places at certain times.
The problem with the “genes cause intelligence” idea is that it confuses the idea of heritability. “Heritability” is a statistical concept. It applies to populations, not to individuals. The causal chain that associates intelligence with ethnicity is unknown. It is therefore assumed to be genetic. If the causal chain that connected first language to ethnicity was unknown, then the assumption of genetics would lead one to the false conclusion that first language was highly heritable.
Grey, you are simply projecting. You don’t have any data. You don’t have any logical arguments that are valid. What do you have?
You say I want to “PREVENT the data”?
What I presume you mean is that there isn’t any data that proves what you think the data will prove once the data is gathered and that I want to prevent such data from being gathered. You are blaming me and people like me for the absence of data confirming what you believe. What you are saying is that your belief is not based on data, it is based on something else.
Now that we are agreed that your belief is based on something other than data, why don’t you tell us what it is based on?
I would like to move the discussion back to facts and logic. I appreciate that leaves you at a disadvantage because the preponderance of evidence doesn’t support your position. If you can supply compelling facts and logic, I am prepared to change my position. You have a very easy way to prove me wrong, just supply the facts that demonstrate that intelligence is something that can be measured (i.e. is not indeterminant from the tests) and that differential genetics are what causes those differences.
@d2u – “There is nothing that conflicts with what I have been saying.”
no, i’m afraid you missed the point.
you said: “It isn’t clear how or what physiology could be changed in a brain to make it more intelligent.”
several are outlined in cochran, et. al. and all of them are genetic diseases.
“I would like to move the discussion back to facts and logic.”
No you don’t. You want to prevent a particular conclusion.
East Africans + training = long distance gold medals
West African + training = sprint gold medals
The difference is genetic.
Hbd, There are some inconsistencies with the paper. They claim 302 Gaucher patients in Israel, but if the prevalence is 0.028, that implies if it is only homozygous, 302/0.028/0.028 = 385,000.
Wikipedia says there are ~3 million Ashkenazi Jews in Israel. There should then be 84,000 heterozygous and 2,352 homozygous.
The data suggesting that the lysosomal disorders might confer some sort of increased intelligence is quite weak.
Whole genome data shows that AJ are more genetically diverse than Europeans, that is they are less inbred.
http://www.pnas.org/content/107/37/16222.full
and that there has not been selection for most of the genetic diseases common in AJ including the lysosomal disorders. Table 2.
I am still looking into this.
Heterosis could explain an increase in intelligence, but that is not via genes per se.
@d2u – “They claim 302 Gaucher patients in Israel….”
yes. patients. but that’s not all the people affected by the disease|condition.
Yes, but without the 302 number being “significant”, then the use of the number of patients to impute via comparison with job description with IQ status has great uncertainty.
The paper I linked to said there was no evidence of selection of Gaucher’s disease in AJ. If there is no selection, then the idea that Gaucher’s disease was selected for because it increased intelligence doesn’t work.
I found a post I made a couple of years ago which I will repost, but I want to update it first.
@d2u – “If there is no selection, then the idea that Gaucher’s disease was selected for because it increased intelligence doesn’t work.”
ok. assuming this is correct, just because gaucher’s wasn’t seclected for in aj because it increased intelligence doesn’t mean that it doesn’t increase intelligence. ¿sí?