Oh, you're right, I am guilty of not reading that closely and was thinking of Plomin's attempt to identify genes linked to IQ.hitssquad said:
I did not claim that his study was based on Scarr's study. I pointed out the important fact that this study was limited to children up to 7 years old. When Scarr did her work, she reached one conclusion when she evacuated her subjects at age 7 and then reversed her conclusion when she tested them again at age 17. Her finding is consistent with all other longitudinal studies in demonstrating that the shared environment component vanishes after age 7 and before age 17.
Thank you. I have read and understood the paper. Whether or not you have read it, your comments indicate that you do not understand it nor how it fits into the big picture.
The study I have read is from Psychological Science, vol. 14, No. 6, Nov. 2003. There is no extrapolation of any finding in that paper to heritability beyond the age of 7. As such, the entire study is of interest only with respect to young children and says nothing about children past the age of 7. All prior research shows that the shared environment component of heritability completely vanishes by age 17.
I didn't quote the sentence. What part of the material you quoted is significant and derived from the study?
That is not what I challenged. You don't understand what he wrote do you? The material you quoted below is precisely the point of my comment.
His study does not supersede anything. It is a study that includes low SES people who have produced lower heredity scores than found in other studies, but under circumstances that the researcher cannot separate from pure genetic or mixed genetic factors. He did not suggest that there is any reason to expect the subjects of his study to mature by a different path than all of the other children who have been studied by longitudinal studies.
And, unlike some folks, I understood it.
You don't appear to understand the material. There was no attempt to study poor minorities, nor was there any attempt to separate the cohorts and study them separately. NONE of the data are based on a single "minority" or population group or race.
You badgered bobf with the article (even though you do not show any appreciation of it) on dates that preceded my joining the discussion forum.
My statement is a simple matter of the record. I have not attacked you personally, I have pointed out the errors in what you have posted.
How much (range)? How extensively has this been tested?Mandrake said:
I'm taking this step-by-step, and per hitssquad's Jensen quote, _g_ correlations are most solidly demonstrated in the US.
You really threw me with this one! :surprise: Aren't you the psychometrician?
I was also thinking of the attempt by Plomin to identify genes linked to IQ. My link to his current research would seem to belie any speculation that he has given up his IQ-gene research — or are you making distinctions between QTL's, alleles and genes?Evo said:
So far, hitsquad seems to be telling you that you have ducked his question.Evo said:
According to an article I read and his home page. He's shifted his focus to another study for now. He never published his findings on his studies linking genes to IQ. I believe there are some others that have picked up that research. The link you posted appears to be related to his current research.hitssquad said:
Well you ducked this question before but might as well try again. What factors did the Turkheimer take into consideration that a higher IQed individual will be more likely to be in higher SES due to the fact that one's IQ level effects one's ability to be in a certain SES level? Rather than the vice versa of SES level effecting IQ. Without taking in such factors, any conclusions by this study will be considered void.Evo said:
I don't know. It is something that I have seen mentioned in various books and papers as part of the discussion of within family variance. Unfortunately, Jensen's books are rather poorly indexed (unlike The Bell Curve) so it is always difficult to find material in them.Nereid said:
I am a physicist with a strong interest in psychometrics. I know the people who deal with intelligence, but that's it. I am familiar with the Myers-Briggs test you listed, but it only relates to intelligence in that intelligent people tend to have a profile that is not common in the general population (INTJ). Adding INTJ and INTP, accounts for 75% of the Mensa level population (per Mensa's report).
Your comments on this single study reveal that you do not understand it nor do you understand how it relates to the rest of the literature. If you think any item I have discussed here is outdated as a result of the study (you have said that ALL were), I challenge you (again) to quote my comments and then show how they are now in error. You didn't accept my challenge before and I doubt that you will now. It is quite evident that you have an attitude, but are not appropriately informed to justify that attitude.Evo said:
The findings of the study were limited to the conclusion that genetic expression may be influenced by SES. The investigators were unable to even sort out genetic from non-genetic factors and said so. What "help" do you think they discussed in their paper? Do you think that they reported any increase in any child due to any aspect of their study?
He addresses that here - Phenotypic SES and IQ are correlated, and that correlation is potentially mediated both genetically and environmentally. Therefore, the models are attempting to detect an interaction between genotype and environment in the presence of a correlation betweenBlackVision said:
Jensen's 1980 book Bias in Mental Testing seems to me to have a good index. But, unfortunately, it is not published on the web. Jensen's 1998 book The g Factor, on the other hand, does have, it seems to me, a poor index, but the fact that Questia (subscription cost at the yearly rate equals 33 cents per day) publishes it on the web makes that somewhat moot since Questia has an in-book search function that even non-subscribers are allowed to use. If you at least own the physical book, you can use the Questia search function as an index to help you find things in the book.Mandrake said:
Mandrake you keep quoting form the same old studies that everyone else has. You are the one that comes unglued if someone posts information that you disagree with. Feel free to attck the material I post, you may prove it wrong. You may not, however, attack me personally for posting a conflicting view.Mandrake said:
The study shows that environment is a substantially significant factor in increased IQ in the children studied and they are continuing this study.Mandrake said:
Your opinion means nothing to me Mandrake. No, I was trying to get BV to answer my questions, which he kept "dodging".Mandrake said:
Myers-Briggs and DISC are both personality tests. Every few years at work we are required to take them. I have been both an INTJ and an INTP in Myers Briggs. My DISC test last year I was a D with a High I. The test before that the two were reversed.Mandrake said:
Exactly which questions am I "dodging"? What an ironic accusation coming from you.Evo said:
Unfortunately, you have not been able to understand that (with rare exceptions) I have not been discussing early childhood in my messages. The study which has overwhelmed you deals only with children up to the age of 7. There is nothing in the paper that projects beyond that age. There is considerable material in peer reviewed sources which suggests that all shared environmental components of intelligence vanish after age 7 and before age 17. You have made numerous comments that you apparently think are related to the Turkheimer paper, which are purely figments of your imagination. One, is your comment about "helping" children. That subject was not discussed in the paper. I asked you about it, but you (as usual) ducked my question. You said that all of my prior comments were invalid because of this paper. The fact is that none are invalid because of the paper. For the third time, I challenge you to simply cut and past my comments from this thread (there are plenty) and show how each of them is invalidated by Turkheimer. You can't do it, but it will be fun to watch you try, or to duck it yet again.Evo said:
Is I have reminded you before, your comments suggest a lack of understanding. The paper shows only that very low SES (a high proportion of impoverished families) causes a large variance in heritability among very young children. Of the 4 tests that were conducted, two were significantly below the age that testing is considered to be reliable (that age is 3, while tests were done at 8 months and 1 year). The study did not state ANYTHING about the influence of environment for higher than "impoverished" SES.
It is much better than The _g_ Factor.hitssquad said:
That is a useful service, but one that I do not have. The approach I have taken has been to create my own index. It is labor intensive, but I find the extra work helps me to recall the contents.
I previously referenced this paper from Intelligence:Moonbear said:
Go for it. I won't complain.Mandrake said:
Moonbear said:
nuenke said:
In regards to heritability, we consider phenotypic variance accountable for on the one hand by environemental variance and on the other hand by genetic variance. If a teen "gravitates toward" specific environments, genetics would be accounting for the variance in environment and hence ultimately accounting for variance in phenotype. What is proposed is not that the teens are shifting from the family to random outside influence, but to ouside influence that caters to the teens' biological programming, of which genetics accounts for the bulk of the variance.Moonbear said:
And what is proposed is that peer selection (among other selections by teens) is not random, but is largely a product of genetically-determined tendency. There is no accounting for taste, as they say, and it is proposed that variance in taste in environment may be more largely accountable for by variance in genetic code than by variance in environment.
Heritability refers to variance in phenotypic outcome accountable for by genetics as opposed to accountable for by environment. Environment is all factors left over when genetic code is controlled for.
Then you are mistaken, because in terms of heritability environment is any factor that is not genetic. That includes the body itself. For example, genetic code expresses throughout a person's life. But the state of the body has visible effects on genetic expression. When people reach physical maturity, their genes still express proteins that code for growth factors. Yet they do not grow any more. This is because of states in the body that prevent growth in the presence of growth factor. One of these states is the hardening of the ends of bones. If the ends of bones remained soft, as they are when we are children, growth factors might continue to stimulate bone growth indefinitely - and people would grow to towering heights throughout their lifetimes, as trees do.
Yes. This is a classic confusion of the term "environment." What normally happens in nature/nurture discussions is that the equivocation fallacy is committed in regards to the definition fo the term environment. One moment it means all environment (all variance not genetic), and the next moment it means only intellectual stimulation. Arthur Jensen suggested that when we discuss environmental variance we be clear about whether we are speaking in terms of biological variance; variance in intellectual stimulation; or all non-genetic cariance (all environmental variance).
There is no environmental counterpart to the discrete gene. In regards to heritability, environment is taken as one big lump and genetics is taken as one big lump. It stands to reason that if it has been established that genetic variance accounts for any amount of variance in a given phenotypic trait that we should also be able to find variance in specific genes that accounts for the same phenotypic trait variance. But searching for genes is not directly a part of heritability studies. Heritability of g in various human populations has already been established by selectively controlling for variance in environment and by selectively controlling for variance in genetic code.
SES is not comparable to a discrete gene. You can silence a discrete gene, but you cannot silence SES. SES is an axis. A gene is quantum piece of code.
No. The gene in question might be coding for the silencing or unsilencing of other parts of the genome. Discrete production of a protein by the IQ-related gene in question may not be necessary for that to occur.
Of course it is affected by environment. Studies of heritability have nothing to do with teasing out discrete affectors. They simply control for variance of environment and genetics and see how that results in changes in variance of expression of one or more phenotypic traits.
hitssquad said:
We need to be explicit in our definition of environment, or, more importantly, various authors' definitions of environment, when discussing it here. I think this is leading to a lot of additional confusion in this discussion.Yes indeed! The political and job related motivations for promulgating false concepts concerning environmental factors is huge. It has resulted in massive spending without returns. We have an inverse relationship between school spending and educational results precisely because the spending has been narrowly focused on population groups that will not show cognitive improvements as a result of the programs advertised to produce gains. The politics of this issue are so robust that I doubt that the subject can be discussed openly in any educational or political forum. The special interest side will simply shout down the scientific findings and use their usual "dirty racist" name calling as their only weapon. This struggle is similar to the Christian church as it sought to stop the advancement of science.nuenke said:
There are shared and not-shared environmental factors. Family factors are the shared ones. I previously quoted from Plomin (this thread) that the shared factors vanish in adolescence. In childhood, the shared factor is about 25%. From there, it goes to zero.Moonbear said:
More likely is that genetic expression increases.
Jensen divides environmental factors into macro and micro, where the macro environment is that which is due to social interactions (family, institutional, etc.) and the micro environment is due to chemical and biological elements. The micro environment includes the intrauterine environment. When you subtract the variance due to genetics (considering intelligence), the factors that remain are environment and error. Together they add to about20-30% of the total variance.
It may well be true that environmental factors account for only 1% of the variance each. I don't see the problem. We know the sum of the genetic influence and we know the remainder is due to the sum of all environmental and error components.
It is relatively unimportant to identify causes of 1% in variance when we can identify the sum. There is no dispute that the sum of all environmental factors is equal to 100% minus the variance in the genetic component, minus the variance due to error. The end finding is completely consistent with the findings of scores of careful research programs.
Mandrake said: