IQ heritability -a question to knowledgeable users

[overtone]

 

 

If with one set of individuals lead exposure falls out as the unique environmental factor and in another set of individuals as the shared environmental factor, then that source of variance will still be either unique or shared and not genetic

How did you get it to "fall out", without measuring it or determining whether it was shared, unique, etc?

 

 

No its not out of context. There is no other way to interpret the claim that "But there is a remaining 20% that depends on external circumstances". What do you think he means by external circumstances if not the environment?

For starters, I can't tell whether he's talking about within population variance or between population variance - something you identified as key to your assertions here. Komlos generally focused mostly on comparing different populations, widely separated in time and space, which would make his comment irrelevant according to you - but without the context, there's no way to tell. Why not find something more scientific and rigorous to reference, like his Wiki page?

 

 

And if ~20% of the variance depends on the environment, where does the remaining ~80% come from...magic? Is it mere coincidence that this figure matches perfectly the estimates of heritability in height being ~0.8?

My guess is they are one and the same, and Komlos that time was discussing within-population variance in height - but Komlos discovery and claim that human populations correctly described vary within themselves by individual genetic inheritance far more than they vary between each other genetically, adds various possibilities to whatever he meant there.

 

Either way, Komlos's discovery that height variance between culturally separate human populations was almost completely environmental serves as a sharp warning to those too glibly interpreting research into the genetic basis of IQ scores. If you don't know whether the individuals you are comparing are from different populations or not, your interpretation of the difference in their IQ scores is quite possibly wrong.

 

 

I have stated several times that I am not making any argument for the variance between populations, but within populations. Every geneticist worth his salt can tell you cant make assumptions about the differences between populations based on the differences within populations. But such differences does not negate the heritability of a trait within the population.

Being unable to identify shared vs disparate environments prevents one from reliably identifying populations or assigning memebership therein.

 

 

Irrelevant. What these studies are trying to explain is the variance itself, not the minimal value

We wish them luck, explaining the variance in IQ without any solid idea of its basis. We discourage assuming "genetic" as the default explanation for areas of ignorance - the history of that assumption is full of embarrassment.

 

 

You also seem to be confused on what I mean by shared environment. Shared environment does not have to be at the population level. If we consider a typical twin study design, the shared environment is intrinsic to each pair of twins.

And your researchers simply assume that they know the extent to which the important and relevant environmental factors for IQ scores as they are measuring them are in fact shared, by these twins - and not shared, by others.

 

That's an assumption, and quite a bit of research - such as the Steele and Aronson studies referred to above, the nature of such factors as lead poisoning, etc - questions its accuracy.

 

In addition, we have presented to us such arguments as patterns of convergence of IQ scores over time in these characterized "shared" vs "unshared" environments si evidence of the genetic influence taking effect; this casts yet more doubt on the quality of the reasoning and research involved. They seem to be overlooking major aspects of the issue.

 

 

 

Well in that case, ~150 years of genetic research is complete bunk....right? Of course not.

A considerable amount of research into IQ is complete bunk, yes. Famously so - "The Bell Curve", written by a Noble Laureate, made it unto television prime time. How much of the research into into IQ's genetic basis is bunk remains to be seen - when someone has described the nature of the genetic influence, the physical expression of code that is exerting the influence on the IQ scores, we will have a better idea of what's bunk and what isn't. That seems to be an event of the distant future.

 

 

 

The point is that countless studies have demonstrated that IQ is very heritable.

And yet, as you pointed out while failing to comprehend a post above, IQ scores are not inherited. So what exactly is being inherited, and what is the nature and extent of its influence on IQ scores?

 

Is there, for example, an inherited social vulnerability to stereotype bias disproportionately lowering the IQ scores of significant numbers of black people in the US, just as it lowered the scores of their parents and will lower the scores of their children?

[iNow]

Overtone, I would ask that you please provide sources for your claims in order to further the discussion. Being able to provide the original data, (i.e. not the New York Times) is important to scientific discussion is it not?

 

Specifically I would like sources on:

 

1) Cumulative environmental effects masquerading as genetic effects (I've asked you for this twice now I think)

 

2) And the specific papers of John Komlos that you cite.

 

Links will be enough, or even titles. I can more than easily access any papers.

I look forward to you supplying me with some actual references in your next post.

Just repeating these requests on your behalf.

[chadn737]

Overtone, why do you refuse to provide sources when asked for them time and again?

[overtone]

 

 

Overtone, why do you refuse to provide sources when asked for them time and again?

Just repeating these requests on your behalf.

Because when somebody keeps misrepresenting my posts and setting up strawman claims I am supposed to be making, posts youtube videos and misrepresented studies that actually work for my claims as "evidence", and so forth, I regard badgering me for sources on stuff like whether lead poisoning is cumulative and affects IQ as more of the same. It's rhetorical thuggery, something that should not be tolerated on a moderated web forum.

 

If it is, it certainly makes no demands on me, any more than any other spam posting would.

 

Been down that road before, and it's a circle. Chase your own tail.

 

On second thought:

 

if you are willing to state publicly that you do not believe lead poisoning from environmental exposure is cumulative and affects IQ scores, and demand evidence

 

and you are willing to state publicly that you are incapable of checking out the names Steele or Aronson or the subject "IQ score bias", have no idea what stereotype bias is and can't find it on the net, and in general are in need of somebody to help you research these arcane topics,

 

then I will apologize for rudely overestimating your abilities, and supply you with links. Fair enough?

[hypervalent_iodine]

!

Moderator Note

overtone, as far as I can tell, the requests made by chadn737 are fairly trivial ones to comply to. Please could you provide some actual links or some form of citation to the papers you are referring to and please could you cite some evidence that cumulative environmental factors are misinterpreted as being genetic in origin. The specific focus on lead poisoning that you keep bringing up is really not relevant here, as you are being asked for evidence for a much broader claim than that.

[chadn737]

Because when somebody keeps misrepresenting my posts and setting up strawman claims I am supposed to be making, posts youtube videos and misrepresented studies that actually work for my claims as "evidence", and so forth, I regard badgering me for sources on stuff like whether lead poisoning is cumulative and affects IQ as more of the same. It's rhetorical thuggery, something that should not be tolerated on a moderated web forum.

 

If it is, it certainly makes no demands on me, any more than any other spam posting would.

 

Been down that road before, and it's a circle. Chase your own tail.

 

On second thought:

 

if you are willing to state publicly that you do not believe lead poisoning from environmental exposure is cumulative and affects IQ scores, and demand evidence

 

and you are willing to state publicly that you are incapable of checking out the names Steele or Aronson or the subject "IQ score bias", have no idea what stereotype bias is and can't find it on the net, and in general are in need of somebody to help you research these arcane topics,

 

then I will apologize for rudely overestimating your abilities, and supply you with links. Fair enough?

 

 

Specifically how do I misrepresent your posts? You have made many strawman arguments in regards to my statements. You are doing it even now. You want me to publicly state that I "do not believe lead poisoning from environmental exposure is cumulative and affects IQ scores" With all due respect, why would I make such a claim when I have never even implied as much. I have challenged your claim that such effects would masquerade as genetic and stated that they would show up as shared or unique environment effects....how you think that means I deny that they can affect IQ scores is beyond me. This is a perfect example of the strawman arguments you have made of my posts throughout this thread.

 

I'm willing to publicly state that the person making the claims has the obligation to support those claims. I have been more than willing to post sources as I make claims, it is not my responsibility to do your research for you.

 

If you find any of these demands to be "rhetorical thuggery" then that is your problem. If you can't handle disagreement and reasonable debate, then that is your problem. I'm sorry, but I am not some ignorant idiot who can be cowed into submission. The fact of the matter is, my arguments are perfectly reasonable, perfectly cordial, but I will call out your fallacies and challenge your arguments.

 

 

How did you get it to "fall out", without measuring it or determining whether it was shared, unique, etc?

 

This is where we need to understand what it is that these sorts of studies actually measure. Twin studies, sibling studies, etc are not typically used to measure specific causes, rather you are measuring the accumulated effect of each category of cause. The narrow-sense heredity h², for instance, does not define specific alleles, but rather captures the accumulated effect of additive genetic variance. In the same way, the unique environment does not define specific environmental effects unique to each individual, but the accumulated effect of each unique environment. Lead poisoning could be a part of that, so could something like abuse or nutrition. The same is true of the shared environment. I think you are confused over this and are under the impression that one cannot measure such effects without knowing the specifics...thats not the case. The experimental design and subsequent statistical modeling allows us to divide the cause of the phenotypic variance into these three broad categories.

For starters, I can't tell whether he's talking about within population variance or between population variance - something you identified as key to your assertions here. Komlos generally focused mostly on comparing different populations, widely separated in time and space, which would make his comment irrelevant according to you - but without the context, there's no way to tell. Why not find something more scientific and rigorous to reference, like his Wiki page?

 

Well I could have done that, had you provided sources long ago when I asked for them. That would give me a chance to read the specific references you use, just as I provide you with the specific references I use for your own critique. That's how this works and when it works, those sources are available for all so that they can also read and make up their own minds. I don't take people's word as authority unless I have reason to. Personally, I'd rather dispense with a wiki all-together, because I like going to first sources, such as the actual research.

 

That being said, whether or not he is talking about between or within group differences, the fact of the matter is that he still cited the fact that 20% of the variance comes from environmental factors....his words. There is really no way to interpret it differently.

 

My guess is they are one and the same, and Komlos that time was discussing within-population variance in height - but Komlos discovery and claim that human populations correctly described vary within themselves by individual genetic inheritance far more than they vary between each other genetically, adds various possibilities to whatever he meant there.

 

The finding that between group differences is less than that of within group differences is not a new finding. Lewontin actaully described this at the genetic level over 40 years ago in his 1972 paper The Apportionment of Human Diversity. This has been a long known fact then amongst geneticists, hence why I emphasize that I am talking about variances within populations.

 

Either way, Komlos's discovery that height variance between culturally separate human populations was almost completely environmental serves as a sharp warning to those too glibly interpreting research into the genetic basis of IQ scores. If you don't know whether the individuals you are comparing are from different populations or not, your interpretation of the difference in their IQ scores is quite possibly wrong.

 

Why would the interpretation be wrong? If you had a wider mix of a population in the study, and environmental effects were explaining that variance, then this would most likely have the effect of increasing the variance attributed to environment, not heredity.

 

There are circumstances where heredity can be overestimated in a twin study, but actually those sources are ones you have not mentioned and do not have anything to do with environmental effects. Rather, epistasis, which can result from dominance and gene interactions, is one of the most common sources of overestimating inheritance. This comes with a caveat, however. For one, it really doesn't effect broad-sense heritability and it really only effects estimates of heritability over 0.5....so a trait already has to be strongly heritable to be overestimated by these effects. Another source of overestimation is when dizygotic twins differ significantly in their shared genetic effects, but again, this is not due to environment masquerading as genetics or because of mixing of populations in the study. Both of these effects are internal to the set of twins themselves, which share the population they belong to. However, there are ways of getting around such biases. Furthermore, they don't apply to assumption free estimates, like those from GWAS (I linked to the paper earlier), which use entirely different methodologies.

 

Being unable to identify shared vs disparate environments prevents one from reliably identifying populations or assigning memebership therein.

 

As in my response to you earlier in this post, this is not the case. Furthermore, we have internal controls in twin studies, because twins, by definitions, will be of the same population.

We wish them luck, explaining the variance in IQ without any solid idea of its basis. We discourage assuming "genetic" as the default explanation for areas of ignorance - the history of that assumption is full of embarrassment.

 

In this case, you are severely misunderstanding the entire purpose. The entire program to build a brain will be genetic and some level of cognition is genetic, otherwise there wouldn't be a brain and cognition for children exposed to high lead to even develop an IQ to begin with. What follows then is the variances in this development, which will be a combination of genetics and environment. At a basic level, yes we are interested in the underlying development of the brain, but at another level, we are interested in understanding why some individuals have IQs over 160 and some under 90. Understanding that variance does not require a "minimal" IQ level to understand. Furthermore, identifying the genetic basis of such variance is one way to identify critical genes underlying the entire developmental program.

Secondly, nobody is assuming "genetic" as the default cause of the variance. I have never stated as much and to imply that I have is a strawman. Rather, I have pointed you to the abundance of research that shows clear evidence for the genetic basis of variance in IQ levels. So my argument rests on what the research has taught us, not some default assumption. I would ask that you stop making such implications about what I say.

 

 

And your researchers simply assume that they know the extent to which the important and relevant environmental factors for IQ scores as they are measuring them are in fact shared, by these twins - and not shared, by others.

This is perhaps one of the first solid criticisms you have made so far. Indeed, twin studies (and some other study designs to an extent) do make assumptions about the degree in which the environment is shared or not shared. This was actually a major flaw in many earlier twin study designs. By early, I mean back in the 70s and early, over 30 years ago. You will notice the research I cite is typically within the last decade or so. However, Structural Equation Modeling allows different models and assumptions to be tested and compared. This largely addresses the criticism you have just stated.

But again, we are also left with the fact that twin studies are not the only source of heritability estimates. Again we have the fact that heritability can be directly measured from the genome in GWAS studies, without making assumptions regarding the nature of the environment. These studies show lower bound heritability estimates of 40% and 51% for different types of intelligence.

That's an assumption, and quite a bit of research - such as the Steele and Aronson studies referred to above, the nature of such factors as lead poisoning, etc - questions its accuracy.

 

I have explained several times how this research does not question its accuracy, at this point you are making an argument from repetition, especially since you have not addressed those arguments.

 

In addition, we have presented to us such arguments as patterns of convergence of IQ scores over time in these characterized "shared" vs "unshared" environments si evidence of the genetic influence taking effect; this casts yet more doubt on the quality of the reasoning and research involved. They seem to be overlooking major aspects of the issue.

 

 

No it doesn't. It has long been known that heritability changes with time with individuals. There are many reasons for this. In some cases, its simply a matter that not all genes are expressed at the same time in development, so their effects are not revealed. We can look at height, which in a growing child is constantly in flux, but stabilizing later in life.

 

A considerable amount of research into IQ is complete bunk, yes. Famously so - "The Bell Curve", written by a Noble Laureate, made it unto television prime time. How much of the research into into IQ's genetic basis is bunk remains to be seen - when someone has described the nature of the genetic influence, the physical expression of code that is exerting the influence on the IQ scores, we will have a better idea of what's bunk and what isn't. That seems to be an event of the distant future.

 

 

The Bell Curve was written by Charles Murray and Richard Herrnstein....neither a Nobel Laureate. And what part of it was bunk pray tell? I have read it, it has parts that are rightly criticized, but that does not make it bunk, particularly given how misrepresented it actually was.

 

This argument also seems like a combination of guilt by association the well and an argument from ignorance. The first, because it attempts to poison the argument using a well known and criticized book to set a bad precedent and associate it with other research. The second, because it appeals to this idea that we simply don't know if the research is bunk (hence ignorance). Well in actuality, we can make a fair judgement of the research based on its methodology. We also have confidence from corroborating lines of independent evidence (twin studies, adoptions studies, GWAS, and more).

 

And yet, as you pointed out while failing to comprehend a post above, IQ scores are not inherited. So what exactly is being inherited, and what is the nature and extent of its influence on IQ scores?

 

Is there, for example, an inherited social vulnerability to stereotype bias disproportionately lowering the IQ scores of significant numbers of black people in the US, just as it lowered the scores of their parents and will lower the scores of their children?

 

 

But they are. If you think that something is not heritable, just because it does not come out matching the parents exactly, then you have deeply misunderstood genetics in its entirety. That, or you have wrongly assumed that I am making the claim that if a trait is heritable, that means its "all genetics" which would be a strawman. Your last argument seems nothing more than an reductio ad absurdum.

Edited January 30, 2014 by chadn737

[overtone]

overtone, as far as I can tell, the requests made by chadn737 are fairly trivial ones to comply to. Please could you provide some actual links or some form of citation to the papers you are referring to and please could you cite some evidence that cumulative environmental factors are misinterpreted as being genetic in origin.

It's an argument - an argument, y'know, a reply to a post? A discussion of something posted and quoted? The evidence I argued from, that cumulative environmental influences not recognized by the researchers can produce the results they attributed to genetic influence in their studies is right there, in the post I was responding to, and in the common knowledge of us all, and otherwise named source. Where else would it be? Whether that actually happened or not is unknown, by anyone - exactly my point. I'm not referring to any papers, in particular, not already present. Is this somehow confusing?

 

Let me try this very, very simply: We have an argument that a demonstrated convergence in IQ scores, compared between shared and unique environments over time, indicates an emergence of genetic influence, from which we can calculate the degree of influence with some precision (it was quantified, and compared with height! the poster was that confident. see above). The studies that concluded this depended for their conclusions on assumptions of shared and unique environment that were not verified - they did not control for lead exposure, for example. I pointed this out. The evidence for what I pointed out was what I was pointing to, already posted, unless you are denying the existence of cumulative environmental influences on IQ scores (I provided at least two examples, one sourced and the other common knowledge).

 

 

As in my response to you earlier in this post, this is not the case. Furthermore, we have internal controls in twin studies, because twins, by definitions, will be of the same population.

You can't define the environmental influences to be not there. You can't assume they are not there. You have to have a thorough knowledge of what they could be, and check for them.

 

Well, apparently you can - but I'm not going to trust the conclusions, and neither should you.

 

 

 

With all due respect, why would I make such a claim when I have never even implied as much. I have challenged your claim that such effects would masquerade as genetic and stated that they would show up as shared or unique environment effects.

You repeatedly badgered me for "sources" for something. There are no sources for my arguments except me, of course, so what were you badgering me about, if not the evidence I employed?

 

You can state whatever you want, but you have not argued or explained how you think a hidden and cumulative environmental influence not distributed in confomance to the researchers's assumptions about shared and unique environments would "show up" to them. I look at those studies, and they have not controlled for several known factors in their classifications of environments as "shared" of "unique", let alone allowed for the fact that since they don't know what physical existant IQ measures they don't know for sure what the relevant factors in a "shared" environment would be. All their conclusions about genetic influence depend on the degree of accuracy of that classification.

 

So this misses the point:

 

In the same way, the unique environment does not define specific environmental effects unique to each individual, but the accumulated effect of each unique environment. Lead poisoning could be a part of that, so could something like abuse or nutrition. The same is true of the shared environment

How did they classify the environments as "shared" or "unique" in the first place? By assumption. Edited January 30, 2014 by overtone

[swansont]

You repeatedly badgered me for "sources" for something. There are no sources for my arguments except me, of course, so what were you badgering me about, if not the evidence I employed?

 

!

Moderator Note

 

This, I think, is the problem. There are arguments and there is evidence. They are not the same thing, so you admit that you have provided no evidence. Repeating arguments without evidence is soapboxing, and that's against the rules.

 

So provide the evidence that supports your arguments. Do not reply to this modnote (and that includes any pleas as to why you shouldn't have to comply with this; it's non-negotiable)

 

[chadn737]

It's an argument - an argument, y'know, a reply to a post? A discussion of something posted and quoted? The evidence I argued from, that cumulative environmental influences not recognized by the researchers can produce the results they attributed to genetic influence in their studies is right there, in the post I was responding to, and in the common knowledge of us all, and otherwise named source. Where else would it be? Whether that actually happened or not is unknown, by anyone - exactly my point. I'm not referring to any papers, in particular, not already present. Is this somehow confusing?

Let me try this very, very simply: We have an argument that a demonstrated convergence in IQ scores, compared between shared and unique environments over time, indicates an emergence of genetic influence, from which we can calculate the degree of influence with some precision (it was quantified, and compared with height! the poster was that confident. see above). The studies that concluded this depended for their conclusions on assumptions of shared and unique environment that were not verified - they did not control for lead exposure, for example. I pointed this out. The evidence for what I pointed out was what I was pointing to, already posted, unless you are denying the existence of cumulative environmental influences on IQ scores (I provided at least two examples, one sourced and the other common knowledge).

 

 

Overtone, do you understand how twin studies, adoption studies, and other family based experimental designs are conducted? In each study design there is of course assumptions made. A long standing criticism of twin study designs has been the Equal Environment Assumption. This is the assumption that a pair of twins, i.e. the two sibling twins themselves, share similar environments, enough so that we can assume that the environment is equal for the two. The EEA, however, has actually held up under scrutiny. See

• Loehlin JC, Nichols RC. Heredity, environment, and personality: A study of 850 sets of twins. Austin, TX: University of Texas Press; 1976
• Kendler KS, Neale MC, Kessler RC, Heath AC, Eaves LJ. Parent treatment and the equal environment assumption in twin studies of psychiatric illness. Psychological Medicine.1994;24:579–590.

​Far more problematic to twin studies, is not the EEA, but rather assumptions regarding genetic relatedness of dizygotic twins and the effects of epistasis, which is a genetic phenomena. However, as I pointed out earlier, the caveat of this latter, however, is that it really only effects traits that are strongly heritable, where the heritability is already over 0.5 (50% of the variance).

 

But there is a much larger problem with your argument that you have ignored, namely that you have multiple different studies and study designs corroborating each other. You have numerous twin studies, taken from many different populations. The idea that lead poisoning will be an equal factor in all, is so unlikely as to be absurd. But then you also have adoption studies, family studies, and GWAS....all corroborating each other on the fact that there is a significant contribution to the variance in intelligence by genetics. This creates a real problem for you, because your arguments will not hold up under all study designs, in particular those of GWAS, which measure the degree of heredity by linkage disequilibrium and do not need to estimate the effects of lead poisoning.

 

You can't define the environmental influences to be not there. You can't assume they are not there. You have to have a thorough knowledge of what they could be, and check for them.

 

Well, apparently you can - but I'm not going to trust the conclusions, and neither should you.

 

 

Thats yet another strawman. I did not say that you are assuming the "environmental influences to be not there". The environmental influences are in fact measured, its just that you don't need to measure specific influences because you are measuring the accumulated effect of the environment, not individual effects.

 

You repeatedly badgered me for "sources" for something. There are no sources for my arguments except me, of course, so what were you badgering me about, if not the evidence I employed?

 

 

I'm badgering you about the original sources of your claims. I have no reason to accept your word on anything. I know nothing about you. Maybe you are the foremost expert in the world on lead poisoning and heredity. Maybe you are some quack. I don't know and I am not going to trust your word on anything alone. Even the foremost researchers, when given the opportunity to write opinion pieces in scientific journals are still required to cite their references for the specific claims they make. If they should do it, then why not you?

 

I believe you that lead poisoning is correlated with lower IQ. What I don't believe is the claim that lead poisoning will masquerade as a genetic cause in studies of heredity. That is the specific claim I am asking you to defend.

 

You can state whatever you want, but you have not argued or explained how you think a hidden and cumulative environmental influence not distributed in confomance to the researchers's assumptions about shared and unique environments would "show up" to them. I look at those studies, and they have not controlled for several known factors in their classifications of environments as "shared" of "unique", let alone allowed for the fact that since they don't know what physical existant IQ measures they don't know for sure what the relevant factors in a "shared" environment would be. All their conclusions about genetic influence depend on the degree of accuracy of that classification.

 

 

The fact that environmental effects are cumulative is irrelevant. These studies do control for such factors. Twin studies actually infer genetic influences in reverse, as they are actually measuring the effect of the environment, not controlling for it. The reason why twins are used, is because of the high genetic similarity. So the study design allows you to control for genetic differences and then measure environmental differences. That's why the biggest errors in twin studies actually come from incorrect assumptions about genetic interactions or relatedness, rather than the environment. As I pointed out above, the EEA has been tested on several occasions and shown to hold up under scrutiny.

 

And again, as I have pointed out several times now, study designs, like GWAS, are not limited by these factors and corroborate previous findings.

How did they classify the environments as "shared" or "unique" in the first place? By assumption.

 

Through an extensively tested methods used in twin studies, not by "assumption".

Edited January 30, 2014 by chadn737

[overtone]

They are not the same thing, so you admit that you have provided no evidence. Repeating arguments without evidence is soapboxing, and that's against the rules.

 

So provide the evidence that supports your arguments.

Look: I did. Several times. My entire simple, obvious, and only argument is based, in evidence, on observations that everyone here has agreed to - that there are environmental factors that are 1) genetically correlated 2) cumulative 3) IQ relevant 4) often hidden. I pointed to two very common and well known examples - lead poisoning and stereotype bias - and named two major and easily checked researchers into stereotype bias in case anyone here was unfamiliar.

 

I already pointed this out to you, in post 57 and elsewhere. Repeated badgering with queries already answered is trolling, and that is against forum policy.

 

 

 

But there is a much larger problem with your argument that you have ignored, namely that you have multiple different studies and study designs corroborating each other. You have numerous twin studies, taken from many different populations. The idea that lead poisoning will be an equal factor in all, is so unlikely as to be absurd.

The question of whether and how much these studies and study designs actually differ from each other, actually are independent, is an interesting one - start a thread? (We know that the early ones - the ones from the mid twentieht century - were corrupted by all kinds of extraneous factors - right?) The objection that lead cannot be the sole and isolated environmental factor causing problems is reasonable, but hardly deals with the issue. I just threw it out as an easy example, an illustration.

 

 

I'm badgering you about the original sources of your claims.

The only source of my claims here is the observations and argument made here. Refer to my posts. Which of my observations do you find false? Or what's wrong with my argument from them? (You occasionally present objections to claims I have not made, and have not dealt with the ones I have made, so I'm not sure you are following things in general).

 

 

The reason why twins are used, is because of the high genetic similarity. So the study design allows you to control for genetic differences and then measure environmental differences. That's why the biggest errors in twin studies actually come from incorrect assumptions about genetic interactions or relatedness, rather than the environment.

Yes, but you are not doing that with these IQ conclusions. When you take the logic backwards - inferring genetic influence from supposedly similar environments - the necessarily prior identification of similarity and difference in the environments is not established in that rigorous fashion. And major or consistent error there corrupts the conclusions.

 

 

 

The environmental influences are in fact measured, its just that you don't need to measure specific influences because you are measuring the accumulated effect of the environment, not individual effects.

If you don't know what the important environmental factors are in your study, you haven't identified the environments in the first place, and you don't know what you are measuring.

 

 

 

The fact that environmental effects are cumulative is irrelevant. These studies do control for such factors.

It is relevant to any conclusion based on IQ score convergence over time, and the studies do not control for what they have not identified even (let alone measured).

 

 

 

Through an extensively tested methods used in twin studies, not by "assumption".

No. There are no such "extensively tested methods" for establishing IQ -relevant similarity and difference in environments. It's not a simple matter: factors such as stereotype bias were overlooked until quite recently, nobody is controlling for lead and similar influences, and so forth. We see studies that use socioeconomic status as a proxy for environment, for example - not nearly alert enough.

 

Illustration, from Claude Steele's work: if you do twin studies in a Western country and you don't control for race, there is going to be an 8-10 point IQ score stereotype bias effect hidden in your study between the whites and blacks - who are consistently non-twins, and also consistently separated by envronmental factors (such as race identification, diet, hypertension, trauma, lead and other chemical exposure, etc) that accumulate in their influence.

 

How many other such hidden population separators are buried in these twin studies?

 

The point is: if you want to simply stipulate that genetic makeup significantly influences the IQ score of any particular person, nobody is going to argue. If you are going so far beyond that as to venture a number - .8 or whatever - then that is dubious. The data is not in.

Edited February 4, 2014 by overtone

[chadn737]

Overtone....do you understand what it means to provide sources? Have you ever written a scientific paper? You are required to cite your sources. There is a reason for that, so that everyone can refer back to the same data that you do. Please provide your sources. Its really not that hard of a task and it would make this discussion much better.

[overtone]

Overtone....do you understand what it means to provide sources? Have you ever written a scientific paper? You are required to cite your sources. There is a reason for that, so that everyone can refer back to the same data that you do.

I'm not referring to any data. I'm not referring to any studies. I am not arguing from any authority. No studies with that argument in them, if there are any, have any more relevant existence or support than the argument itself, which you persist in blowing off for troll questions.

 

You have stipulated to the existence of environmental factors of the kind my argument requires (hidden, cumulative, genetically correlated, IQ influential). Do you have any other relevant response?

Edited February 4, 2014 by overtone

[chadn737]

I'm not referring to any data. I'm not referring to any studies. I am not arguing from any authority. No studies with that argument in them, if there are any, have any more relevant existence or support than the argument itself, which you persist in blowing off for troll questions.

 

You have stipulated to the existence of environmental factors of the kind my argument requires (hidden, cumulative, genetically correlated, IQ influential). Do you have any other relevant response?

 

If you are not referring to any data or studies, then you are making up the correlations to lead poisoning. You are making up the idea that environmental effects can masquerade as genetic effects. You are making up the idea that one has to specify the environmental effect....your entire argument then is baseless and made up.

 

That is what you are saying....that you made it all up out of thin air. Since when does any scientific argument not reference data or studies?

 

You have a very weird concept of what trolling is. Typically the troll is the person who doesn't refer to any facts or sources...not the one asking for them and putting in the effort to provide them. So who's really the troll here?

[overtone]

 

 

If you are not referring to any data or studies, then you are making up the correlations to lead poisoning. You are making up the idea that environmental effects can masquerade as genetic effects. You are making up the idea that one has to specify the environmental effect....your entire argument then is baseless and made up.

The correlations of lead exposure and city neighborhood, hence race and ethnicity and geographic heritage, hence genetics in some aspects, are common knowledge. Everybody knows black kids from the slums are more likely than most to ingest lead - or is that news to you? Maybe it's news to you that black people, like most people, tend to live near family, migrate to city neighborhoods where their relatives and hometown friends are established, - lord knows what you are oblivious to in the world of human beings.

 

That environmental effects can be difficult to separate from genetic influences when the researchers cannot distinguish similar from different environments (in the IQ relevant respects) is an observation I made right here, based on your description and posting. It's an immediate consequence of the methods you stated were used to separate out the genetic influence - comparing similar genetics in different environments, and similar genetics in different environments, and so forth. Is it wrong? If so why?

 

 

 

You are making up the idea that one has to specify the environmental effect....your entire argument then is baseless and made up

Of course I "made up" my argument. So? It certainly itsn't "baseless" - the basis is right there, for you to critique whenever you get around to it, someday.

[swansont]

Look: I did. Several times. My entire simple, obvious, and only argument is based, in evidence, on observations that everyone here has agreed to - that there are environmental factors that are 1) genetically correlated 2) cumulative 3) IQ relevant 4) often hidden. I pointed to two very common and well known examples - lead poisoning and stereotype bias - and named two major and easily checked researchers into stereotype bias in case anyone here was unfamiliar.

 

I already pointed this out to you, in post 57 and elsewhere. Repeated badgering with queries already answered is trolling, and that is against forum policy.

 

 

!

Moderator Note

The moderators are the arbiters of forum policy, not you. You have not been badgered with "queries already answered", because those queries were for citations to scientific studies to back up your claims, and you have not done this.

 

Until this happens, the staff has decided that any further posts will simply be hidden from view.