Talk:Heritability of IQ/Archive 1

Archive 1

Archive 2

Inbreeding

Charles the III of Spain of the Hapsburgs was an imbecile, and he only had 8 great grand parents. What heading should that go under? 128.206.82.56 (talk) 21:19, 16 June 2009 (UTC)done

Let me state this better. There is clear evidence for inbreeding leading to intellectual deficits. 128.206.82.56 (talk) 16:13, 13 July 2009 (UTC)done

how many great grandparents was he supposed to have? — Preceding unsigned comment added by 140.247.25.6 (talk) 15:52, 12 June 2013 (UTC)

Title change

I suggest changing the title to "Heritability of intellgence" since almost all material is about Heritability. The current title is somewhat POV since it seems to imply genetics. Objections? Ultramarine 02:51, 19 February 2007 (UTC)

Although I second the change in title, I would like to even go further - "intelligence" is a somewhat problematic term, with unscientific connotations, whereas "IQ" has an unambiguous meaning. Thus, "Heritability of IQ" could be even more appropriate as an article title. Harkenbane (talk) 22:58, 8 March 2008 (UTC)

I agree with Harkenbane, go ahead! --Crusio (talk) 10:32, 9 March 2008 (UTC)

As you can see, I've moved the page. But doing so has rendered some passages extraneous; since I'm the one who actually moved the page, I'll try to take responsibility for cleaning the article up over the next few days, but I hope others will try to make necessary changes as well! Harkenbane (talk) 02:26, 10 March 2008 (UTC)

I strongly disagree. "IQ" is simply a number derived from a test of intelligence. It cannot be inherited, and it does not directly correspond to intelligence. Various factors such as education, language and culture affect the correlation between intelligence and IQ. I'd say we rename the article to "Heritability of intelligence." 202.40.139.164 (talk) 11:59, 6 November 2008 (UTC)

I think you're wrong here. "Intelligence" is a concept, as such, it cannot be measured directly. What we measure is an IQ test score, from which we infer the intelligence level. But all that we measure remains the IQ score, nothing more, nothing less. As multiple studies have shown, there is significant heritability for IQ scores. The factors affecting IQ that you describe (education, culture, etc) are environmental factors and because of their presence, the heritability of IQ scores is not 1. --Crusio (talk) 16:31, 6 November 2008 (UTC)

Just one question

Just one;

If intelligence is hereditary, why is it that the overwhelming majority of ultra smart people in the United States do not come from "noble ancestry?"

I mean, most Americans are descended from "European trash," e.g., the working class. To me that doesn't sound like good genetic pedigree regarding the breeding for brains.

Since the majority, the overpowering majority of Europeans who came here were all from "trash" stock, this country should have no smart people at all.

A big, glaring problem with the heredity argument. Indeed, a college professor of mine, whose brother got into that whole ancestry thing, discovered that their great grandfather was a coal miner. From coal miner, to college professor. Its not the only incident either, there are many others. Many people in this country, who teach at Ivy league institutions, who have won nobel prizes, often descend from the lowest of the low from Europe way back when. In Australia, which was originally a prison colony, there are many people there with high I.Q.'s Most of those people are descended from criminals and brigands the British government had deemed "feeble minded."

Of course, I'm not here to make a statement, but to pose a question; if intelligence is inherent, if its inborn, if its genetic, why is it that at one point all of humanity lived in a state of savagery?

Another question I have is, if Europeans according to tests supposedly have higher level II intelligence, I need to ask, why was it that northern Europeans, the ones promoted as being smarter than everyone else, lived in a state of barbarism for hundreds of years?

If intelligence was truly genetic, you'd think they would have created a civilization as sophisticated as that of ancient India or Persia. Were are all the pyramids in Norway? Were are the ancient cities in Germany? Were are the Ankor Wats of England?

No mean to insult anyone here but Stonehenge, when compared to the pyramids in Central America, is hardly an example of brain power.

Is the heredity of intelligence "science" real science, or, is it racist junk science out to abuse its authority to promote racist views?

Nazi Germany abused science in a similar manner; more worrysome though, is the lack of research in how intelligence can be increased. People seem perfectly comfortable in assuming, what you got is what you got, and there is nothing you can do about it.

Sucks for nonwhites, but very convenient for whites. I'm just saying, I hope racist egotism is not the motivating factor for that "science" and "research."

206.63.78.105stardingo747 —Preceding comment was added at 08:23, 8 November 2007 (UTC)

Oh dear, stardingo747.... There is so much to say about this. Intelligence is not genetic. It has a heritable component. Like most complex characters ("complex" here referring to the underlying causes), genes have an influence, so has environment, and often these two interact (meaning that the effects of one depend on the state of the other). Although your above points are well-taken, they do not contradict at all the article as it currently stands. --Crusio 22:40, 9 November 2007 (UTC)

Stardingo. If the people who built Stonehenge were so 'backward', how is it that you're here today speaking in the language of their distant descendants? Runcero (talk) 10:10, 1 November 2009 (UTC)

What now

Too often people work on articles by picking a POV and looking for sources to back it up. I think the way to research an article is to find out what the notable verifiable sources are and then find out what they say (what views they hold) and then come up with an outline for an article that accommodates their views and whatever arguments exist among them. Following this principle I have discovered that there are plenty of good scientific research on the heritability of traits including IQ. A sample of key studies:

• Bouchard, Arvey, Keller, Segal, 1992, Genetic Influences on Job Satisfaction: A Reply to Cropanzano and James,” Journal of Applied Psychology 77(1): 89-93
• Devlin, Daniels, Roeder 1997 “The heritability of IQ” Nature 388: 468-471
• Jacobs, Van Gestel, Derom, Thiery, Vernon, Derom, and Vlietinck, 2001, “Heritability Estimates of Intelligence in Twins: Effect of Chorion Type,” Behavior Genetics 31(2): 209-217
• McCartney, Harris, and Bernieri, 1990, “Growing Up and Growing Apart: A Developmental Metanalysis of Twin Studies” Psychological Bulletin 107(2) 226-237
• Phelps, Davis, Schwartz, 1997, “Nature, Nurture and Twin research Strategies” in Current Directions in Psychological Science 6(6): 117-121
• Plomin and Loehlin, 1989, “Direct and Indirect IQ Heritability Estimates: a Puzzle” Behavior Genetics 19(3): 33-342
• Race, Townswend, Hughes, 285-291, “Chorion Type, Birthweight Discordance, and tooth-Size Variability in Australian Monozygotic Twins” Twin Research and Human Genetics 9(2) 285-291 (no, not about IQ – but as it is about other clear phenotypic traits it provides a good benchmark for assessing the value of twin studies and the various factors one must also take into account)
• Reed, Carmelli, Rosenman, 1991, “Effects of Placentation in Selected Type A Behaviors in Adult males in the national Heart, Lung, and Blood Institute Twin Study,” Behavior Genetics 21(1) 1-19
• Segal, 19999, Entwined Lives: Twins and What They Tell us About Human Behavior
• Sokol, Moore, Rose, Williams, reed, and Christian, 1995, “Intrapair Differences in Personality and Cognitive Ability Among Mynozygotic Twins Distinguished by Chorion Type,” Behavior Genetics 25(5) 456-466
• Stromswold, 2006, “Why Aren’t Identical Twins Linguistically Identical?” Cognition 101(2): 333-383

Now, I have not read most of these, but this is precisely my point: I have not chosen them because they support my POV, but because they are frequently cited by scientists and thus represent notable views, whatever their views are. And this is plenty of material to work through. Slrubenstein | Talk 16:22, 17 December 2007 (UTC)

Actually, I think that most of the key points in the article are already there; most of the revision right now should focus on organizing and formatting the existing material, in my opinion. That stated, I can see a few areas to expand and explore:

• One thing I've been seeing for quite some time now is that there are not likely to be any genes with major effects on IQ, only a great many with minor and minuscule effects that only become important when these effects are aggregated. If anyone knows of any genes with major effects on IQ, that would be important to add.
• Also of interest would be whether heritability remains high outside of developed nations; what is the heritability of IQ in, for example, India?
• Lastly, a brief section on the nature of intelligence may be in order, dealing with g theory and critics who offer alternative models; if intelligence is something besides g, then IQ should not be the focus for the article as it currently is. Harkenbane (talk) 22:54, 8 March 2008 (UTC)

It might be good to also include some comment on the nature of heritability, especially emphasising the fact that heritability is not the same as heredity. We do say that heritability is the relative contribution of genes to variance for a given environment, but maybe we need to emphasise this by specifically saying that it is not a measure of the relative contribution of genes to a trait. It's not at all obvious to the lay person that a contribution to variance is not the same as a contribution to the trait itself. We might also include some small discussion of the validity of hereditary measurements, I know a lot of scientists are sceptical that heritability estimates are at all useful or that they tell us anything worth knowing. There are several papers we can cite for this, in particular David Layzer's paper Heritability Analyses of IQ Scores: Science or Numerology? (it's a bit odd that this very important and directly relevant paper is not cited at all), but also including Commentary: Heritability estimates—long past their sell-by date, The analysis of variance and the social complexities of genetic causation The analysis of variance and the analysis of causes Commentary: Statistical analysis or biological analysis as tools for understanding biological causes, though the emphasis for these latter four deconstructions of heritability should be in the heritability article, which does not seem to contain any critisism of the concept at all. What do you think? Alun (talk) 07:04, 27 March 2008 (UTC)

Overhaul

Discussion brought over from the Race and Intelligence page:

What do people mean when they claim that racial differences cause differences in IQ? According the the lead, it sounds like some people think that race stands for biological differences. In the "Race" section above Alun demonstrates that for biologists race is subspecies and there are no meaningful human races in a biological sense. The question is whether there is a genetic component to differences in IQ scores and this question has nothing to do with "race." Study on the biology of IQ hinges on twin studies. Here is a fair sample of the major sources:

This isn't an article about "race." Harkenbane (talk) 18:39, 26 March 2008 (UTC)

To start us off, I propose we look at these articles:

• Bouchard, Arvey, Keller, Segal, 1992, Genetic Influences on Job Satisfaction: A Reply to Cropanzano and James,” Journal of Applied Psychology 77(1): 89-93
• Devlin, Daniels, Roeder 1997 “The heritability of IQ” Nature 388: 468-471
• Jacobs, Van Gestel, Derom, Thiery, Vernon, Derom, and Vlietinck, 2001, “Heritability Estimates of Intelligence in Twins: Effect of Chorion Type,” Behavior Genetics 31(2): 209-217
• McCartney, Harris, and Bernieri, 1990, “Growing Up and Growing Apart: A Developmental Metanalysis of Twin Studies” Psychological Bulletin 107(2) 226-237
• Phelps, Davis, Schwartz, 1997, “Nature, Nurture and Twin research Strategies” in Current Directions in Psychological Science 6(6): 117-121
• Plomin and Loehlin, 1989, “Direct and Indirect IQ Heritability Estimates: a Puzzle” Behavior Genetics 19(3): 33-342
• Race, Townswend, Hughes, 285-291, “Chorion Type, Birthweight Discordance, and tooth-Size Variability in Australian Monozygotic Twins” Twin Research and Human Genetics 9(2) 285-291 (no, not about IQ – but as it is about other clear phenotypic traits it provides a good benchmark for assessing the value of twin studies and the various factors one must also take into account)
• Reed, Carmelli, Rosenman, 1991, “Effects of Placentation in Selected Type A Behaviors in Adult males in the national Heart, Lung, and Blood Institute Twin Study,” Behavior Genetics 21(1) 1-19
• Segal, 19999, Entwined Lives: Twins and What They Tell us About Human Behavior
• Sokol, Moore, Rose, Williams, reed, and Christian, 1995, “Intrapair Differences in Personality and Cognitive Ability Among Mynozygotic Twins Distinguished by Chorion Type,” Behavior Genetics 25(5) 456-466
• Stromswold, 2006, “Why Aren’t Identical Twins Linguistically Identical?” Cognition 101(2): 333-383

I repeat, the point is not to cherry-pick quotes that we agree or disagree with. The point is to examine reliable sources to find out - yes, find out, as if e may actually learn something new - what the notable views are.

I disagree with the implication that those of us who contribute to this article have not already carried out a literature review - at the very least, that isn't true in my case; I regularly read Intelligence along with other psychological journals. Harkenbane (talk) 18:39, 26 March 2008 (UTC)

From what I gather from this literature, most of the current scholarship - mainstream scholarship - on IQ scores is not even concerned with the debate "is it environmental or is it genetic."

Yes, because the heritability of IQ throughout the developed world has been settled (although the heritability of IQ in developing countries is unknown). Harkenbane (talk) 18:39, 26 March 2008 (UTC)

There is a body of literature, and I provided many citations above, and obviously an article on this research must be organized around the most notable and mainstream views on the matter - it should include all notable views ... but I think that the major notable views should be the principle factor in the organization and presentation of the article.

Virtually all scientific research on the genetic determinants of variation in IQ scores is based on twin studies and above (perhaps now in archived talk) I provided a bibliography of major (i.e. from major peer-reviewed journal journals, and which are frequently cited) articles. These studies indicate an ongoing debate between scientists who measure the heritability of intelligence at .40, and others who measure it at between .60 and .70.

The debate is not ongoing. Research on children shows low heritabilities; on adults, high heritabilities. That the heritability of IQ is below .5 in early childhood and above .7 in late adulthood is commonly accepted throughout the psychological community. Are you aware of any study published in the last 20 years which breaks this trend? Harkenbane (talk) 18:39, 26 March 2008 (UTC)

In addition to these contrasting calculations, there is a debate over the effects of of the shared prenatal environment - some argue that identical blood supply should lead to greater similarities between monochoriatic twins than dichorionic twins; others argue that competition for blood supply should lead to greater differences between monochorionic twins than dichorionic twins. I think we need to have a good article that provides a clear account of this research and these controversies.

You seem to be in a good position to do this; why not simply add it to the present article? Harkenbane (talk) 18:39, 26 March 2008 (UTC)

Perhaps someone who has training in genetics and access to these journals could take the first step in sketching out an article on Heritability and IQ.? Slrubenstein | Talk 20:33, 25 March 2008 (UTC)

Not about intelligence, not about race

This is an article about the heritability of IQ - specifically, the proportion of variance in IQ which is attributable to genetic variance. Consequently, I don't think this is the place to discuss race, intelligence, or race and intelligence. Questions about whether IQ measures "intelligence," whether "race" exists, or whether different populations differ in IQ for genetic reasons, can be addressed elsewhere. Harkenbane (talk) 19:05, 26 March 2008 (UTC)

Harkenbane, my apologies for my confusion about the deletion of comments. To respond to yours, I only wish to reiterate two points. One, I agree with youcompletely that this is not about "race," but the question of heritability of IQ constantly comes up on the Race and Intelligence page. I do not think this article should be rewritten to be about race (unless that is what the notable sources say), I wish only to point out the relevance of this article to another. Two, none of my comments are directed at you personally and I hope you do not take them personally. I have added other sources and topics I think this article should cover; this in no way disparages the work you or others have already done. Slrubenstein | Talk 12:13, 27 March 2008 (UTC)

No need to tread on eggshells. I will say, however, that the relevance of this article to the article on race and intelligence is not large so long as the article sticks to its subject, for the straightforward reason that within group heritability really says nothing about between group heritability. If users on another page are making claims about the within group heritability for IQ which contradict what is written here, I think they should take their concerns to this article - the information given here, while cluttered and poorly presented, is nevertheless that of the mainstream psychological community. If anyone has any information to the contrary of what currently appears, please make the appropriate changes with proper citations! Harkenbane (talk) 17:59, 28 March 2008 (UTC)

I think that's right Harkenbane. The only relevance it has is to do with heritability, in that some researchers claim that because the heritability of IQ is high for some groups then this indicates a string genetic component to the trait, and also that a high heritability for one group must mean a high heritability for all groups. But this is more about these researchers (notably Jensen) conflating heritability with heredity and making false claims about the validity of between group heritability. This article already makes the specific point about within group heritability not being relevant to between group heritability. I do think this article should be more explicit in distinguishing between heredity and heritability. Alun (talk) 18:57, 28 March 2008 (UTC)

Race is an illusion of the flesh, but genetics is not. If an ethnicity is revealed to have a higher genetic predisposition towards learning disabilities by a scientific study, those conducting the study should not be labeled as racist just for their findings. In reality race is but the demographic distribution of genetic traits and it's the problem traits that are the problem, not the race. I personally think it's pathetic that we tend to only classify race by a handfull of cosmetic and superfluous traits that have no impact on personhood other than that our species is weak minded enough to identify with and mimic the behavior of people who look similar to us. IQ is about measured intelligence by the way, the word intelligence is in IQ for a reason. --67.58.85.10 (talk) 17:27, 23 February 2009 (UTC)

Genetics of intelligence

Genetics of intelligence redirects to this article. However I do feel there may be a distinction between the genetics and heritability. Heritability can be measured without the knowledge of the actual genes such as measuring traits over several fruit fly generations. It might be necessary to have a separate article, genetics of intelligence, that focuses only on genes that have been associated with intelligence. Wapondaponda (talk) 23:36, 26 January 2009 (UTC)

Controversial because it's uncomfortable

I hate how legitimate studies are labeled controversial simply because they raise uncomfortable questions or go outside the comfort zones of established mainstream religions. The studies on the genetic factors effecting intelligence are controversial because they raise uncomfortable questions about this "all men born equal" mindset we've been taught to blindly accept.

Face it, everyone isn't born equal, look up birth defects if you don't believe me. Genetics plays a large role in many things, it's still labeled controversial that Genetics effects sexuality even though not a single scientist in the field would deny it, and this is controversial because it brings up bad memories from history class or raises issues relating to ethnicity and demographic areas. We're every bit as subject to genetics and natural selection as the next species and we need to get over our tendency to undermine legitimate scientific case studies just because we don't like what they may reveal to us. Without knowledge we have no power.--67.58.85.10 (talk) 17:21, 23 February 2009 (UTC)

Between-Group Heritability: Revisions & New Article

SUMMARY: Need balanced coverage of section "Between-group heritability", and link to a larger entirely new article on statistic in social science

PROBLEM #1: Coverage of opposing camps in the section titled "Group Comparisons" is not fair/balanced

DETAILS: As of 3:50 pm, US Central Time, Friday, July 3rd, 2009, there are 2 paragraphs in this section. There are a total of 1192 (949+253) characters typed and allowed in favor of one view. Yet there are only 229 characters which have been allowed to represent the opposing view.

The first paragraph is 939 characters (including spaces), which presents the view that between group comparisons of heritability cannot be made for psychometric measures.

The second paragraph is 479 characters (including spaces) and includes 2 sentences. The first sentence is 229 characters, and presents an outdated weak argument supporting the validity of between group comparisons. Rather than proceed to qualifications, expansion, or (better yet) a superior argument from the 'other side', this paragraph then returns to the initial camp, and presents yet another sentence supporting that view, 253 characters long. Strangely, this additional sentence add no value to the argument, save the dropping of another name (it makes no argument, adds no explanatory or evidential information not already presented above).

PROBLEM #2: The debates over statistical significance of group comparisons on psychometric tests is too large to be covered here, and is relevant to many other topics besides intelligence

Yet a third issue, which I attempted to at least mention briefly in this section, is the wide spread deep debates over the significance of statistical comparisons of groups of humans on the basis of psychometric tests. A much large article covering this topic should be created by a QUALIFIED scientist. It should include sections discussing cases of public deception, as well as political motivations. Most importantly though, it should include the actual GENERALLY ACCEPTED standards used in various areas of social and medical research. If lives depend on it, a much higher standard is used for determination of effect size and statistical significance. If it is merely a tool for the elucidation of human nature, for the development of governmental policies, funding, and educational curriculum, or other less "valued" purposes, then the standard is lower. Lastly, this new article should also include some graphical examples depicting important experimental design concepts, such as the masking or confounding of effects, when using only a few descriptive statistical tools. Mostly social researchers are familiar with debates in inferential statistics, but the more fundamental philosophical issues are more esoteric.

Paul.J.Richardson 21:12, 3 July 2009 (UTC) —Preceding unsigned comment added by Paul.j.richardson (talk • contribs)

I think the issue is that Wikipedia requires verified information and rejects original research. Of course there are many strange "facts" in articles that are not properly sourced (and so not verified), but the aim is to verify everything, particularly in articles with a serious scientific basis. The rejection of original research may seem a little harsh, but you will agree if you consider the thousands of POV-pushers and simply ignorant editors that want to include extremely dubious information into a variety of articles. At any rate, the best strategy would be to concentrate on some specific text in the article that you believe should be improved and find some sources to support new text. Johnuniq (talk) 01:25, 4 July 2009 (UTC)

Between-group heritability

This edit changed:

But when one compares the means of the two plots, the variation is entirely environmental, since the between-group genetic differences are not significant.

to:

But when one compares the means of the two plots, the numerical difference between means is mostly environmental, since the within-group genetic differences average out.

I changed "the between-group genetic differences average out" to the second of the above since it looks good to me, but I'm happy with either wording (although sticking to the source would be best). Johnuniq (talk) 01:02, 4 July 2009 (UTC)

An inconsistency

"A 2004 meta-analysis of reports in Current Directions in Psychological Science gave an overall estimate of around three quarters.[8] The New York Times Magazine has also listed about three quarters as a figure held by the majority of studies.[9] This coefficient would imply that r squared is about 0.56, meaning that about 56% of the variance in IQ scores is genetic."

The study under [8] gives no heritability measurement. For doubters, it can be easily accessed from a google search. The measurement for 56% is also considerably lower than the 75% measurement, yet it has no notation. Also, it's rather pointless to quote the NYT article when it gives no citations. —Preceding unsigned comment added by 71.205.11.120 (talk) 17:33, 14 July 2009 (UTC)

Better sources

http://www.news-medical.net/news/2005/04/26/9530.aspx —Preceding unsigned comment added by 76.85.196.138 (talk) 18:04, 15 November 2009 (UTC)

New info from Race and intelligence

I moved a lot of info here from Race and intelligence per a proposal in mediation. Subsequently it has been suggested that information on between-group heritability of IQ should not take up so much space here. I'd like to see how we can best address this issue.

The lead states that this article is primarily about in-group heritability. Why is that? Should between group heritability of IQ not be discussed here at all?

Much of the new info is admittedly about hypotheses to explain the correlation between IQ and race without a mostly hereditarian explanation. I agree that this may not be the best place for this info. Please give ideas for other articles that would be more fitting for this information, while avoiding POV forks (which was my aim in keeping all the information together). T34CH (talk) 20:17, 18 December 2009 (UTC)

Clarification

In regards to the "Inconsistency" piece, that post was incorrect in saying that 56% and .75 were unconnected, considering how 56% definitely is .75 when r-squared. However, the NYT article should be disregarded since it gives genuinely no source. The 2004 paper cited should also have more detail given from it. Are they listing a correlation coefficient or the percentage variance? If possible, papers with public domain access should be listed. There's also no actual reference given on the Posthuma 2002 paper.

On another note, it should also be clarified how much more heritable g is than IQ. —Preceding unsigned comment added by 68.62.1.91 (talk) 21:28, 4 January 2010 (UTC)

Improving the “between-group heritability” section

This section of the article still has some of the same problems that were originally raised during the mediation case for the now-defunct Race and intelligence article, as well as some new problems that resulted from the split. I’d like some attention to be paid to fixing them.

What was a problem previously, and still is one, is that instead of explaining the arguments that are presented in favor of between-group IQ differences being heritable, the “heritability” section devotes a large amount of space to explaining almost nothing. While WP:UNDUE demands that we not devote a larger portion of space to any hypothesis than it receives in the source material, it does not demand that our explanation of a minority viewpoint be uninformative. A new problem is that “heritability” should not be only one subsection of the section “between-group heritability”, because the entire section is discussing between-group heritability. Most of the content of this section was copied verbatim from the Race and intelligence article, in which it was explaining factors which could affect between-group differences in IQ, but if it’s going to be presented as factors which could raise or lower between-group heritability, it’ll need to be reorganized.

I think the best solution to this might be something that DJ proposed during mediation for the Race and intelligence article, which is to take a data-centric approach, focusing on individual lines of data which could affect between-group heritability, rather than on viewpoints about whether it’s heritable or not. Here are some of the specific data points that DJ suggested the article cover:

• the implications of within group heritability for between group heritability
• Spearman's hypothesis and reaction time data
• adoption and early intervention programs
• structural equation modeling of between group differences
• regression equations among siblings
• brain size and other biological correlates
• evolutionary models (see the January (2009) issue of PAID)

This would be in addition to the lines of data which the article discusses already, such as health and quality of education.

I also think that if the scope of this section is limited to discussing factors influencing between-group heritability, several of the points discussed here aren’t relevant, and should be either removed or moved to the Between-group differences in IQ article. For example, the question of test bias that’s raised in the test construction section is relevant to the question of whether IQ can accurately be compared between cultures, but this is a separate question from whether and to what degree between-group differences are heritable.

Before I go about making any of these changes, I’d like to make sure nobody has a significant problem with them. Does anyone have any improvements to suggest about what I’ve proposed here? --Captain Occam (talk) 00:32, 7 January 2010 (UTC)

That all seems reasonable. Be bold! David.Kane (talk) 04:26, 7 January 2010 (UTC)

I’m glad you approve, but I’d prefer to also get an opinion from either DJ or Varoon Arya. I haven’t seen either of them around recently, but I’d like to give them at least a day or so to let me know what they think about the best way to improve this section. --Captain Occam (talk) 12:06, 7 January 2010 (UTC)

POV fork of race and intelligence

I get the impression that this article is slowly becoming a POV fork of the race and intelligence article. It seems that large sections that were part of the race and intelligence have now moved here. I believe the scope of this article is the heritability of intelligence, not supposed differences in intelligence between groups, that is a separate subject. Wapondaponda (talk) 15:32, 7 January 2010 (UTC)

what did you expect? the race and intelligence article should never have been split this way - it's a notable and well-defined topic, even if it was badly named - and so of course the chunks of it are going to morph back into the original article. just a pointless move all around... --Ludwigs2 17:04, 7 January 2010 (UTC)

I’ve just moved most of the content in question from this article to Between-group differences in IQ. I think it makes sense for the Heritability of IQ article to have a few paragraphs discussing between-group heritability, but I agree with the rest of you that most of the information about theories regarding the cause of the IQ difference would be more relevant in that article than in this one. --Captain Occam (talk) 10:01, 8 January 2010 (UTC)

What is intelligence?

After more than 140 years after the creation of the word "eugenics", I must question two things:

1-How many races exists in the world? And Why there's 3,4,5,6,7,8,9,10,10,etc. races in the world?

2-What is intelligence? After read many eugenics tracts, I realized that a person why hight level of IQ/intelligence is someone very bigoted, racist and charlatan. Am I right or wrong and why?

This Israeli site: [Jpost] makes another question: Are Taliban descendants of Israelites?Agre22 (talk) 21:09, 10 January 2010 (UTC)agre22

this page is not here to speculate on that issue, which has not currently been resolved to anyone's satisfaction. this page is only here to discuss the various perspectives that people have had on the question over time. --Ludwigs2 23:02, 10 January 2010 (UTC)

Outright copy and pasting

Some of the paragraphs in the "caveats" section are lifted word for word from the APA statement. There should be more original work in that regard. —Preceding unsigned comment added by Mannoro (talk • contribs) 01:58, 9 February 2010 (UTC)

Education and Intelligence

The birth rate for people with low IQs is MUCH higher than those with high IQs, yet the mean IQ of the world keeps rising and rising. If genes really determined intelligence this would make absolutely no sense. The mean intelligence is increasing because of education. Education = higher IQ, Genes do not = higher IQ. —Preceding unsigned comment added by 68.161.166.90 (talk) 23:24, 7 April 2010 (UTC)

New Paper by Bouchard and His Fellow Researchers Should Be Known to All Editors of This Article

Johnson, Wendy; Turkheimer, Eric; Gottesman, Irving I.; Bouchard Jr., Thomas (2009). Beyond Heritability: Twin Studies in Behavioral Research. Current Directions in Psychological Science, 18, 4, 218.

This is a paper I learned about from Johnson, Gottesman, and Bouchard directly, as I happened to be in the "journal club" in their University of Minnesota Department of Psychology during fall semester 2009. It includes the important conclusion, "even highly heritable traits can be strongly manipulated by the environment, so heritability has little if anything to do with controllability," which does a lot to clarify the issues discussed in this article. I take it that everyone who has ever looked at good sources on this topic has heard of Bouchard (and his co-author Turkheimer). Both of these scholars have modified their conclusions in recent years, as they have continued to follow up the data sets they study and to interact with other researchers. —Preceding unsigned comment added by WeijiBaikeBianji (talk • contribs) 11:12, 5 June 2010 (UTC)

Intelligence Citations Bibliography for Articles Related to IQ Testing

You may find it helpful while reading or editing articles to look at a bibliography of Intelligence Citations, posted for the use of all Wikipedians who have occasion to edit articles on human intelligence and related issues. I happen to have circulating access to a huge academic research library at a university with an active research program in these issues (and to another library that is one of the ten largest public library systems in the United States) and have been researching these issues since 1989. You are welcome to use these citations for your own research. You can help other Wikipedians by suggesting new sources through comments on that page. It will be extremely helpful for articles on human intelligence to edit them according to the Wikipedia standards for reliable sources for medicine-related articles, as it is important to get these issues as well verified as possible. -- WeijiBaikeBianji (talk) 19:57, 30 June 2010 (UTC)

You are very welcome to suggesting further sources. It's time to update this article based on more current sources, as many of the sources currently cited in this article are obsolete in light of further research. -- WeijiBaikeBianji (talk) 23:22, 4 October 2010 (UTC)

Who has reference number 1 at hand?

I see today a version of this article in which the first statement with a footnote is "Heritability is a measure of the relative contribution of genotype to the variation of a phenotype on a given group in a specific environment." I rather doubt that that is the exact definition of heritability given by any current reliable source (this doesn't appear inside quotation marks in the article), but let's check. What does the cited source actually provide in its own exact words as a definition of "heritability"? How many of you have that source printed out or available online as you edit this article?

-- WeijiBaikeBianji (talk) 13:53, 27 July 2010 (UTC)

Try here: http://ije.oxfordjournals.org/cgi/reprint/35/3/525.pdf pgr94 (talk) 14:26, 27 July 2010 (UTC)

I also have full text access to the cited reference, and will now edit this Wikipedia article accordingly. -- WeijiBaikeBianji (talk) 13:45, 28 July 2010 (UTC)

Considering a merge in of other articles and a title change here.

There has been article talk for a while at some other articles, on the subject of environmental influences on IQ, in which editors have proposed merging those articles with one another or into other Wikipedia articles. This Heritability of IQ article stands out currently as the best sourced, and evidently most watched, of the several articles about various influences on the development of IQ. We can all note for the record that the technical term "heritability [of trait]" of course does not solely mean "genetic influence on [trait]" but rather "estimated balance of environmental and genetic influence on [trait in a particular population]." Thus it might be in the spirit and fact of what this article is really about to retitle it to Environmental and genetic influences on IQ or something like that, with appropriate redirects. This issue is open for your discussion while I read some new sources (copyright 2010) that I have just obtained from academic libraries. Let's discuss what would bring about a yet more current, even more accurate, and clear and educational article on this frequently contentious topic. -- WeijiBaikeBianji (talk) 00:03, 10 August 2010 (UTC)

WP:Article titles should be based on common names for the topic rather than trying to be precisely correct. The google test isn't definitive by any means but 'environmental and genetic influences on IQ" only got 5 hits and taking the quote marks off only brought it to the same level as "Heritability of IQ" quoted literally. "Heritability of intelligence" didn't do as well but was quite respectable. Dmcq (talk) 08:59, 10 August 2010 (UTC)

Dmcq, I was just in a discussion with another editor on a completely unrelated article about article titles, so I can see where you are coming from with your friendly comment. I'll ponder some more which form of restructuring the existing supply of articles will be most helpful to readers and most consistent with established Wikipedia policies and guidelines. -- WeijiBaikeBianji (talk) 16:35, 11 August 2010 (UTC)

A good discussion of this issue by a statistician.

I was browsing around looking for sources for this and other articles, and found an excellent online post, which, although it is not a Wikipedia reliable source, definitely points to a lot of sources that are Wikipedia reliable sources and analyzes those sources with sound judgment. This is a good post to look at while preparing to edit this article. -- WeijiBaikeBianji (talk) 20:37, 11 August 2010 (UTC)

P.S. I expect to edit this article more actively now, as I note that many of the sources are obsolete (there are now much better sources on the same issue), and not all of the sources now in the article follow best practice for sourcing Wikipedia articles. -- WeijiBaikeBianji (talk) 23:24, 4 October 2010 (UTC)

I removed the "regression towards the mean" section

To the extent that such a discussion is warranted here, the correct argument is here. Tijfo098 (talk) 20:45, 14 October 2010 (UTC)

Well, I put it back, but some parts need better explaining and citations. Also a picture like File:Resp-to-sel.jpg would be much more informative, although just for one individual rather than selected population, although that one is still better than a generic regression pic. Tijfo098 (talk) 22:56, 14 October 2010 (UTC)

POV in lead

Rose SP is dissing the entire subfield of quantitative genetics, arguing that it is completely useless nowadays [1]. This is definitely a POV, and should not be used in the lead, especially unattributed. This is not at all how a textbook like Hartl and Clark (which has good reviews [2]) presents the topic. Some nuance is needed. Tijfo098 (talk) 08:55, 15 October 2010 (UTC)

From the book review: "Although the text does not discuss it, the cited paper also showed that there are a large number of genes that are not affected by the environment and/or the background genotype, so phenotypic plasticity is just one of the things that may or may not influence development and survival on the way from genotype to phenotype." A more NPOV presentation is at http://plato.stanford.edu/entries/population-genetics/#StaPopGen Tijfo098 (talk) 09:09, 15 October 2010 (UTC)

Also, Google scholar finds only 3 citations for Rose's 2006 paper. Not exactly a ringing endorsement. Tijfo098 (talk) 09:27, 15 October 2010 (UTC)

Rose is very much committed to a nurture viewpoint. He's been writing this stuff in his books for decades. He had more luck with people paying attention to his arguments against evolutionary psychology than against quantitative genetics, it seems:

• Against biological determinism (1982; only 37 citations)
• Alas, poor Darwin: Arguments against evolutionary psychology (eds. but he wrote the scathing intro, 2000; 260 citations, but you should read the Amazon book reviews [http://www.amazon.com/Alas-Poor-Darwin-Evolutionary-Psychology/product-reviews/0609605135/ref=sr_1_1_cm_cr_acr_txt?ie=UTF8&showViewpoints=1], especially the one by Dennis Littrell -- can't link directly to it thanks to Wikipedia's idiotic software -- who dissects Rose's style of setting up strawmen—a relevant issue in this wiki article as well.)

Tijfo098 (talk) 09:45, 15 October 2010 (UTC)

However, the general point that a heritability estimate says nothing about malleability (also called mutability or changeability) of a trait is correct science, and is identified in numerous reliable secondary sources as an issue about heritability that is most often misunderstood in public discussions of heritability. The statement is so noncontroversial and mainstream that I can back it up with multiple citations—as I intend to in the planned edit I have already announced here—without any reliance on Rose's publication at all. P.S. I have several textbooks about the subject at hand, including one by Hartl. -- WeijiBaikeBianji (talk) 15:26, 15 October 2010 (UTC)

Good recent edits.

I see an editor is checking references for this article and making sure that statements in article text match what the cited references actually say. I will try to add some references, first to this talk page, and later to the article. I appreciate any editor who checks references to make sure that they are being used correctly. -- WeijiBaikeBianji (talk, how I edit) 23:44, 4 November 2010 (UTC)

Is there any discussion of article tag here?

I see the article is tagged, as of November 2010, but I don't see a new section of article talk here discussing that. What's the concern? -- WeijiBaikeBianji (talk, how I edit) 04:50, 5 November 2010 (UTC)

I think you tagged it. [3]. aprock (talk) 06:15, 5 November 2010 (UTC)

That being the documented case, I've removed the tag. Thanks Aprock. 72.228.177.92 (talk) 11:46, 26 November 2010 (UTC)

Clarification requested

Section "1.1.1 Background" says: Heritability is defined as the proportion of variance in a trait which is attributable to genotype within a defined population in a specific environment. But two sentences later it says The heritability of many traits can be considered primarily genetic under similar environmental backgrounds. This leaves me confused: together the sentences seem to say "The proportion of variance attributable to genotype can be considered primarily genetic." Am I missing something? I suspect that the second quoted sentence is misworded and should start out as "The determination of ..." instead of "The heritability of ...." Duoduoduo (talk) 16:25, 20 December 2010 (UTC)

Merging "IQ and environment" articles

See discussion here[4].--Victor Chmara (talk) 22:32, 20 January 2011 (UTC)

Note on shared environment

I wanted to note that the twins reared apart research shows a slight shared environmental effect in adulthood. See the Bouchard study discussed here[5], the best study of reared apart twins to date.

Based on this, I wanted to ask a larger question-- if this methodology gives different results than other methodologies, might it make sense for us to devote a sub-section at the beginning (perhaps called "Techniques" or "Methodologies"to the various methods that have been used to calculate the heritability of IQ? We could then, within that discuss the assumptions they make which might bias the heritability to be higher or lower.

In No Two Alike, JR Harris makes the argument that the twins reared apart studies are more reliable than the twin studies, because those studies are biased by assumptions like equal environments. That's the type of thing that would go in the section I'm proposing.

Note: I've posted a related idea on restructuring the sections below.--Babank (talk) 23:57, 2 April 2011 (UTC)

There is also an article about heritability in general. More general discussions should probably be there.Miradre (talk) 00:29, 3 April 2011 (UTC)

Agreed, though its common practice to summarize necessary background information and link to the main article with the {{main}} template. The methodological differences between the reared apart studies vs the conventional twin studies are relevant here, in that they produce different heritability estimates. And I've cited a reliable source which makes light of this fact. What are your thoughts on my proposal?--Babank (talk) 00:40, 3 April 2011 (UTC)

Regarding the proposal below I have replied there. Regarding giving more details as described above that seems fine to me.Miradre (talk) 00:50, 3 April 2011 (UTC)

Seperating sections

I think we should seperate the parts that define Heritability and its caveats from Methods and Results. Results and methods section should deal with the behavioral genetic techniques and the results they produce, not with defining heritability..

I would put the Correlations in this new section as well, as this is related only to defining/calculating Heritability, not the behavior genetics research.

Under my proposal here, we would have a Heritability section preceding the Methods and Results section. Any thoughts on this idea?--Babank (talk) 23:59, 2 April 2011 (UTC)

A section for defining heritability seems fine. Correlations can also been seen as a topic of its own. So maybe a structure would be "Correlations", "Definition of heritability and caveats", and, "Estimates of the heritability of IQ".Miradre (talk) 00:41, 3 April 2011 (UTC)

Hmm, now that I look at the Correlations section, does it really make sense to list the correlations, as they vary from one study to the next? By listing those correlations we're privileging that study over all the others. I think it would make more sense to show a chart of heritability estimates from twin or adoption studies, as they do on that link I posted above. So what do you think about removing the correlations section (aside from the parts necessary to explain what heritability is)? --Babank (talk) 01:06, 3 April 2011 (UTC)

I think the correlations section should remain. Different studies may give somewhat different estimates but the same applies to heritability.Miradre (talk) 01:25, 3 April 2011 (UTC)

Fair enough. Are the correlations there from a meta-analysis? I'd just prefer that we use a meta-analysis rather than one particular study.--Babank (talk) 21:06, 3 April 2011 (UTC)

Alan S. Kaufman gives the sources as Kaufman, A. S., Lichtenberger, E. O., Fletcher-Janzen, E., & Kaufman, N. L. (2005). Essentials of KABC-II assessment. Hoboken, NJ: Wiley, and Sattler, J. M. (2008). Assessment of children: Cognitive foundations (5th ed.). San Diego, CA: Jerome M. Sattler. Miradre (talk) 23:18, 3 April 2011 (UTC)

Changed the sections as suggested above. Thoughts?Miradre (talk) 23:24, 3 April 2011 (UTC)

I like the new section layout. I'm going to create a suggested Todo list for this article, tell me what you think.--Babank (talk) 20:47, 4 April 2011 (UTC)

Some edits

• I removed the sentence on personality, as the article is about IQ/intelligence, not personality. And IQ/intelligence does have shared effects.
• I added a contrary view on shared environment based on reared apart studies

--Babank (talk) 20:58, 4 April 2011 (UTC)

Proposed cleanups and additions

What does everyone think of making these changes:

• Merging caveats into Heritability section as text. Basically keep the same content, but make it flow as encyclopedic articles are supposed to.
• Instead of listing the correlation, but them to the right or left of the text as a table or chart image.
• Let's add some of the charts found here from various studies[6]. If there's a copyright issue, we can recreate them.
• Should the Galton chart really take up so much space? It's of historical importance, but not really important in a scientific sense, as it doesn't control for shared environment.
• The between group heritability section seems to fall under the Caveats section more than anything. I propose that we move it up, both to keep things organized, and to also give it the prominence it deserves.

Thoughts?--Babank (talk) 21:03, 4 April 2011 (UTC)

All of this looks like good ideas.Miradre (talk) 07:21, 6 April 2011 (UTC)

Removing Regression to the Mean section

The section had no sources which discussed regression to the mean in the context of this article. The "IQ Testing 101" source mentions "regression to the mean" once in the test as a passing remark. Reviewing the history of this article, the section has been essentially unsourced since it's introduction three years ago [7] in what seems to be a copy/paste dump from somewhere else. aprock (talk) 06:11, 1 August 2011 (UTC)

Unsourced is not a reason for deleting. Unverifiable is. You should have put on a template asking for better citations. Do you seriously dispute what is there? Dmcq (talk) 18:09, 1 August 2011 (UTC)

I take it that you will in due course provide the required sources per WP:BURDEN. This isn't an issue of disputing the content. I mean, we could add the entire plot synopsis to Star Wars, and I wouldn't dispute the content. I've looked through various sources, and found nothing indicating that this concept is relevant to the topic of the article. aprock (talk) 18:10, 1 August 2011 (UTC)

So you agree first that the concept is not unsourced but you dispute that regression to the mean has anything to do with the topic of the article which is heritability of IQ. Is that correct? Could you expand a bit please as it seems to me to be pretty relevant to the topic. Dmcq (talk) 18:57, 1 August 2011 (UTC)

The relationship between regression to the mean and this article is unsourced. Certainly various mathematical concepts relate to the analysis of data used in researching the topic. That does not mean we need to include a section for each mathematical concept. There is no need to summarize mean, variance, correlation, probability, etc in the article. If you think it's relevant to the topic of this article, then supplying sources indicating that it is relevant to the article topic would be helpful. aprock (talk) 20:28, 1 August 2011 (UTC)

So you are now saying sourcing something saying a relation between regression to the mean andf heritability and inheritance to IQ is the main problem? I find it hard to believe you found nothing with a quick search using google but okay I'll have a quick search myself and see what happens if I stick something in. Dmcq (talk) 20:35, 1 August 2011 (UTC)

Unfortunately, of the ten Eysenck books my library has available, that is not one of them. Could you please briefly summarize the discussion of regression to the mean included there? All of the "regression to the mean" discussion I've seen in the context of heredity are simple discussions of how the tool is used to set up hypotheses for analysis of data. aprock (talk) 21:14, 1 August 2011 (UTC)

Just stick 'intelligence: a new look' into google books and click on the google books result which will be first. It will show you those particular pages in full. Exactly what have you got against discussions of the use of a simple tool in setting up the hypothesis? Anyway let's see what your particular objections are to this. Dmcq (talk) 21:26, 1 August 2011 (UTC)

I can only view pages 1-14. The search result indicates that "regression to the mean" is mentioned once in those pages, with what looks like a simple explanatory note. As discussed above, including the mathematical particulars of any one statistical tool is undue here. It is not the job of wikipedia to walk readers through the statistical calculations made by researchers. aprock (talk) 21:42, 1 August 2011 (UTC)

I was able to log into a computer half way across the country to get fresh credentials, and reviewing the source, it seems that the proper content the source supports is something along the lines of: "Like all heritable traits, IQ also obeys the law of regression to the mean. The aggregate IQ of offspring will be between the average IQ of the culture into which they are born and the IQ of their parents." That certainly doesn't require an entire section, detailing the mathematical models and nuances. Given that "regression to the mean" is a general feature of heritable traits, any such discussion might belong in that article. However, the lack any discussion about that concept in heredity indicates that it is, as expected, undue there as well. aprock (talk) 22:10, 1 August 2011 (UTC)

Well that's an advance I suppose from the complete elimination of the term from the article altogether. The term was invented in the context of the measurement of intelligence by Galton (well in fact regression to mediocrity) and is very often discussed in the context of intelligence - a number of pages were devoted to it in that book for instance discussing the misapprehensions people have about the concept and what it actually means. The article you should have looked at is heritability, heredity simply refers to the mechanism. I'm happy enough that some of the maths can be taken out or perhaps better copied to the heritability article since it is a bit thin overall. I think people have been most interested in it in the context of intelligence even though it also applies to things like height of course. Dmcq (talk) 22:56, 1 August 2011 (UTC)

Galton's development of the term has a high profile in regression to the mean, although he developed the concept in the context of plant height, not human intelligence. You'll note in that discussion that "regression towards the mean occurs in all bivariate normal distributions". This is not a concept which is generally understood to be under the rubric of heritability. Rather, like arithmetic, the scientific method, and statistics in general, regression to the mean is just one of many tools used in heredity. That pages in a popular book are devoted to mathematical tools for the purposes of making an argument is not surprising. But if the explanation was done in the context of introduction the concept for later use, that does not establish any sort of weight that such a discussion should be rehashed here. We do have an entire article on the topic already. I appreciate your note on heredity vs. heritability. As neither article discusses regression to the mean, including extensive details about concepts related to heritability in general in this article hardly seems appropriate. aprock (talk) 23:11, 1 August 2011 (UTC)

Galton did lots of things. This article actually explains it better than the regression to the mean article if people are going to get hung up about bivariate normal distributions. That is a minimum condition, saying it occurs when there are a number of contributory factors like this article does is a more straightforward way of explaining it. The topic does have weight here because it has been discussed in this context at length in scholarly works. Dmcq (talk) 07:35, 2 August 2011 (UTC)

The topic may have weight for extensive discussion somewhere, but not in this article. As discussed in the Eynsenk source, the law of regression to the mean with respect to heredity is not unique to IQ. aprock (talk) 14:31, 2 August 2011 (UTC)

There is a fuller article elsewhere and it is referenced, this article should deal with its application in this context. It looks like this has come to an impasse with you simply declaring that it shouldn't be in even though it is dealt with in length in relevant texts, take it to a noticeboard if you think you have some valid grounds. I can't see your grounds so I can't suggest a suitable place or state what you think neutrally so you might prefer to raise an WP:RfC Dmcq (talk) 21:40, 2 August 2011 (UTC)

Sounds reasonable, thanks. aprock (talk) 21:48, 2 August 2011 (UTC)

Highly gifted men and the percentage of their highly gifted male relatives

This section appears to be about heritability of giftedness, defined by various measures, not heritability of IQ. It consists of a single large table with no accompanying discussion. I suspect this is undue, with the content being more appropriate for inclusion on the pages of the individual researchers or the Giftedness page. Seeking constructive feedback, aprock (talk) 17:32, 1 August 2011 (UTC)

Agree the stuff should be in the other article and is undue here. There should probably be a small section here referencing the other article and linking the two in some way but that's about it. Dmcq (talk) 18:11, 1 August 2011 (UTC)

RfC on inclusion of extensive regression to the mean content in Heritability of IQ

Question: Should the section Heritability_of_IQ#Regression_toward_the_mean be included in this article?

Currently, inclusion of this content in this article is based on three sources:

• Intelligence: A New Look. paraphrased: "Like all heritable traits, IQ also obeys the law of regression to the mean. The aggregate IQ of offspring will be between the average IQ of the culture into which they are born and the IQ of their parents." pp 37-39
• IQ Testing 101 which only notes regression to the mean in passing on page 143
• http://www.ndsu.nodak.edu/instruct/mcclean/plsc431/quantgen/qgen6.htm A brief web page on plant genetics

I'll note that none of these sources imply that regression to the mean is a particularly meaningful aspect of the Heritability of IQ. In fact, the most authoritative source on the subject, the Intelligence book, notes that it's a general characteristic of all heritable traits. While the mechanics of computing expected regression to the mean may be interesting to some, they do not belong in this article. If they belong anywhere, it is in the main regression to the mean article, or possibly the heritability article. While I feel that the section is out of place in the article, I fully support including content parallel to the paraphrased description of what is in the Intelligence book above.

Input invited, aprock (talk) 22:13, 2 August 2011 (UTC)

• I believe a section on it should be included as it has been discussed at length in books dealing with the heritability of intelligence. That it is a common notion does not mean it should not be included where writers in the field have shown an interest in it. It was ridiculous deleting the subject and all mention of it. Some of the maths could be moved to another article but there's quite enough of interest and value pertaining to the topic and why it is relevant in calculating heritability of intelligence and the figures its use gives. Dmcq (talk) 22:30, 2 August 2011 (UTC)

comment: sources which corroborate this view would certainly be useful in supporting it's inclusion. aprock (talk) 22:50, 2 August 2011 (UTC)

You had your say above, be specific about exactly what you think was not supported if you're going to append extra comments to what I said. Dmcq (talk) 07:13, 3 August 2011 (UTC)

• Not as currently written - The current section "Regression toward the mean" has several significant flaws: (1) missing citations; (2) too much information unrelated to 'IQ'; and (3) too much information that is better in the Regression toward the mean article. The section should be severely pruned to contain only material that is (a) found in reliable sources, and (a) directly related to IQ by the sources themselves. Note that some of the sources may say "regression toward the mean is not applicable to IQ", and that is okay ... they can be included also. --Noleander (talk) 23:35, 2 August 2011 (UTC)

  Are you saying the section should be removed until such time if ever someone writes it better or are you talking about editorial tags? Also could you point out a source please saying the effect is not applicable to IQ, I think that would be an extremely interesting. Sorry I see you're just making a general hypothetical. Dmcq (talk) 07:10, 3 August 2011 (UTC)

  Perhaps you were referring to that heritability here isn't the same as correlation with a parents IQ and one needs to be careful about what the effect regression to the mean actually has and why? Dmcq (talk) 11:41, 3 August 2011 (UTC)

Let me try to clarify my point: (a) every sentence in the section should have a citation to a WP:Reliable source ... if there is no source, the sentence must be deleted; (b) the source must be discussing IQ in relation to "regression towards the mean" ... if the source is discussing RTTM in isolation (not mentioning IQ) it does not belong in this article, but in the RTTM article instead. Following these two simple guidelines should clean up the section and make it acceptable. --Noleander (talk) 13:34, 3 August 2011 (UTC)

So are you one of these who demand every single statement must be cited and be practically a direct copy of the source, plus every single statement must mention heritability and IQ. Or is summarizing pages from sources which are explicitly about the inheritance of IQ enough? Dmcq (talk) 18:03, 3 August 2011 (UTC)

No, I don't think that characterizes my interpretation of WP policy. Let me clarify: the WP:verifiability requires that all contentious material be accompanied by footnotes. Furthermore, the WP:Original research policy forbids including material in an article unless the sources of the material are discussing the topic of the article. Those are clear policies. Thus, in this article on a contentious topic, material cannot be included unless it arises from a source, and that source is discussing heritability of IQ. Period. As for the issue of directly quoting sources, the WP guideline suggests that directly quoting (or close paraphrasing) is discouraged, and instead an encyclopedic narrative should be employed which summarizes the source. Turning to this RfC's issue: the article has two problems: (1) many key assertions are not supported by sources; and (2) many of the assertions appear to arise from sources that are discussing RTTM in general, without any reference to IQ, and that violates WP policy. --Noleander (talk) 17:17, 5 August 2011 (UTC)

I interpret that and your original comment as meaning you agree it is okay to include a bit in this article from sources if they deal with intelligence and the chapter deals with heritability even if the general method is more general. The generality is dealt with by a see also or main. Material which can be moved to the general article without destroying the sense here should be moved. The stuff left needs to be sourced a bit better and be closer to the sources. I have been unwilling to waste time editing the section without some establishing of the ground rules because aprock has gone to some length above opposing including anything about it at all on the basis that it is 'a general characteristic of all heritable traits'. Dmcq (talk) 22:06, 5 August 2011 (UTC)

I'll be happy to look at the material and give my opinion. Can you give me the following info: (1) the source(s); (2) a brief summary of what they say on this topic; and (3) how does this material relate to IQ (best if the source itself makes the connection to IQ). If you provide that info, here, I'll give you my opinion. --Noleander (talk) 22:08, 5 August 2011 (UTC)

Until proper sourcing for inclusion, I suggest that the section be reduced to a brief summary of how regression to the mean relates to Heredity/IQ based on the Eysenck source. Any objections. aprock (talk) 20:24, 8 August 2011 (UTC)

I agree that the material should be reduced to such a summary, now. The section, as it stands, is not properly sourced and a violation of the OR policy. Later, if editors present additional, on-point, sources, we can add more material. But even then the sources much make the connection to the topic of IQ .... editors cannot make that connection. --Noleander (talk) 21:04, 8 August 2011 (UTC)

Okay for the moment, I've a bit of stuff to do in the real world first. I'll be basing the main thing on the Eysenck citation pointing out the misunderstandings and what the relation actually is. I'm not sure what your emphasis on 'editors cannot make the connection' is about. It strikes me as hiding something rather like the stuff aprock went on about that noting must be here since it was used elsewhere as well. It made no sense to me and I felt they had an ulterior motive which they were not stating. Dmcq (talk) 21:58, 8 August 2011 (UTC)

Dmcq: You ask "I'm not sure what your emphasis on 'editors cannot make the connection' is about. " Let me explain how that is a violation of OR: If I have two sources A and B, and A says "Grand canyon is a big hole" and B says "it is theorized that UFOs created big holes in the earth", I cannot then add into a WP article "it is theorized that UFOs created the grand canyon". I would be putting together two sources to create a new statement that no source says. Apply that to this article: There may be sources that say A: "IQ is hereditary", and B: "Hereditary traits often follow statistical law XYZ.", but an editor cannot from those two sources write the statement "IQ follows statistical law XYZ". Look at it this way, if RTTM really does apply to IQ, it will be easy to find sources explicitly saying so, and those sources can be used for the article. But if such sources are not found, that means the scholarly community really hasn't made that conclusion yet. --Noleander (talk) 22:05, 8 August 2011 (UTC)

To clarify here, the Eysenck source does say exactly that "like other heritable traits, IQ follows regression to the mean". What it does not say is that "computation of regression models is of particular interest to the heritability of IQ", which is what about 85% of the section discusses. aprock (talk) 22:10, 8 August 2011 (UTC)

Okay. My point was simply that the article's text must restate, in encyclopedic prose, what the sources say. I guess my examples could have been better :-) --Noleander (talk) 22:15, 8 August 2011 (UTC)

Well for instance the text on page 39 goes on to say the degree of heritability can be determined from the regression and it has an example it goes through of the social status of children compared to that of parents and gets a heritability of 70%. I'm pretty certain that qualifies. Dmcq (talk) 22:26, 8 August 2011 (UTC)

I'm not sure how illustrating heritability computations with social status indicates that such computations are particularly of interest to the IQ trait as opposed to heritability in general. aprock (talk) 22:52, 8 August 2011 (UTC)

Which I believe illustrates my point about your objection pretty clearly and why I go to some trouble to try and elucidate what Noleander means. Dmcq (talk) 23:06, 8 August 2011 (UTC)

Anyway that a lot of he stuff would be better elsewhere is not a reason for saying that the topic should be removed completely without even a see also. Actually I'm not certain the article is improved if one just sticks in the results without a single line formula which gives the value. It isn't as though the formula is gone into in any detail. Dmcq (talk) 22:30, 8 August 2011 (UTC)

• I agree not as currently written. Regression to the mean is a notable concept relevant to heritability of IQ, but I'm afraid its current treatment is inadequate, at times almost incomprehensible (even to those who already understand the concept). 174.99.120.98 (talk) 02:15, 20 August 2011 (UTC)

removing section till rewritten

Based on the feedback provided, I've removed the section for the time being. If it can be rewritten with better sourcing indicating it's relevance to the topic here, then we can add it back. aprock (talk) 17:19, 4 January 2012 (UTC)

Correlations section

This section does not discuss heritability at all. Rather it presents various correlation numbers, for what purpose it is unclear. I've moved the section to the end, and unless some sources can be found which relate the specific correlation content presented back to heritability, I think it should be removed. aprock (talk) 21:22, 13 September 2011 (UTC)

These are heritability correlations. This is precisely the info I came to get from this article: NUMBERS! — Preceding unsigned comment added by 93.89.200.51 (talk) 18:14, 26 November 2011 (UTC)

There is no such thing as a heritability correlation. Heritability and correlation are two different statistical measures. Some use correlation to estimate heritability (see [8]), but the result is heritability, not correlation. aprock (talk) 22:15, 26 November 2011 (UTC)

This is standard intro psych textbook material.

Heritability estimates refer to the statistical partitioning of covariance into environmental vs. genetic sources of variability between genetically unrelated individuals in a population, and this index varies from 0 to 1.

The correlations between the IQ scores of genetically related individuals is what is being reviewed in this section, and varies from -1 to +1. Data presented in this section indicates that the greater the degree of genetic relationship between two individuals, the higher correlation between their measured IQ. This does not give a heritability estimate; however, this data is corroborative of the hypothesis that IQ is influenced by genetic factors. Memills (talk) 04:26, 28 November 2011 (UTC)

This does not give a heritability estimate, quite correct. this data is corroborative of the hypothesis that IQ is influenced by genetic factors, this is original research. In genetics, it is heritability which is considered, not bald correlations. aprock (talk) 04:50, 28 November 2011 (UTC)

No, it is not OR. In fact this stuff is in virtually all intro psychology textbooks.

Also, a heritability estimate (as a statistic -- a number) is different from the concept of heritability (not a number).

The info presented here, again, is corroborative of the claim that there is heritable variation in IQ between individuals, as evidenced by the increasingly similar IQ scores of more closely genetically related individuals. That is precisely the point that is made when this same information is presented in intro psych textbooks. Nothing new, extraordinary or controversial here. Memills (talk) 17:22, 15 December 2011 (UTC)

By all means do provide sourcing. Given your history of tendentious editing, I suspect an RfC will be a better use of time. I'll write one up when I get the chance. aprock (talk) 17:35, 15 December 2011 (UTC)

As I said, check any intro psych textbook.

Can you provide a ref that suggests that the increasingly similar IQ scores of more closely genetically related individuals is irrelevant to the issue of heritable variation in IQ? Or, should we just take your word for it? Memills (talk) 18:10, 15 December 2011 (UTC)

The psych book on my shelf says nothing about correlation of intelligence being a more relevant statistic than heritability when it comes to measuring heritability. Your suggestion that sources are used to exclude information rather than include information is exactly backwards. Until you provide some sources, I'll defer further conversation for the RfC. aprock (talk) 18:34, 15 December 2011 (UTC)

The issue isn't whether which one is more relevant -- both are. See: Regression/correlation methods of estimation of heritability and the references therein.

Also, the information in this section is already referenced.

If you are suggesting that the increasingly similar IQ scores of more closely genetically related individuals is irrelevant to this topic, the heritability of IQ, and thus this sub-section should be deleted, please back up that assertion with a ref(s). I have never heard / read anyone make such a claim. Memills (talk) 21:20, 15 December 2011 (UTC)

Based on the above discussion, I removed the section yesterday, and it was restored this morning without meaningful explanation. Some basis for inclusion needs to be demonstrated, or the section will have to be removed. aprock (talk) 15:00, 26 April 2012 (UTC)

Restored section. A reference is provided -- and, this information is presented as relevant to the issue of the heritability of IQ virtually all intro psych textbooks. If you want more references, any intro psych textbook (or references therein) will do.

Per the discussion above, the burden is on Aprock to provide references that suggest that the increasingly similar IQ scores of more closely genetically related individuals is irrelevant to the topic of the heritability of IQ. That will be a difficult task. Memills (talk) 19:44, 27 April 2012 (UTC)

The content does not discuss the topic of the article. The WP:BURDEN is always on those who wish to include content. To date, you've failed to name a single source which supports inclusion of htis content. I'll give you another day or two to find a source which supports inclusion of this material. aprock (talk) 00:29, 28 April 2012 (UTC)

Support Memills. Reference is given and content is obviously about the article topic. Academica Orientalis (talk) 00:46, 28 April 2012 (UTC)

If the material does stay it should be brought inline with WP:NPOV. The section currently cherry-picks data to support a WP:FRINGE WP:POV and excludes mainstream data found in the sources provided...

Fischbein (1980), in a study of twins, divided his samples into three groups categorized by social class. He found that heritability estimates increased with increasing social class. The estimate of broad heritability from the intraclass correlations for identical and fraternal twins was .78 for the highest social class, but only .30 for the lowest. Extremely similar results were obtained from a large-scale study of 1909 non-Hispanic Caucasians and African American sibling pairs (identical twins, fraternal twins, full and half siblings, Cousins in the same household, and biologically unrelated siblings) from the National Longitudinal Study of Adolescent I lealth who were tested on Wechsler's Vocabulary subtest (Rowe, Jacobson, & Van den Oord, 1999). When categorized by parental education, the heritability for the most highly educated families averaged .74 versus a value of .26 for the less well-educated families(Rowe et al.). In a twin study conducted in Russia, Crigorenko and Carter (1996) evaluated the parenting styles of the mothers of identical and fraternal twins, and analyzed these relationships as a function of the family's social class. They found parenting styles to differ for the two types of twins (e.g., mothers of identical twins employed more infamilization, invalidation, and authoritarianism than mothers of fraternal twins), and for different social classes. Regarding the latter point. Grigorenko and Carter found that Russian mothers with less education and lower occupational status were more likely than their more educated, higher status counterparts to use authoritarian approaches, to view their children's behavior less positively, and to invalidate and infantilize their [P31] twins' behavior. The latter two styles were also associated with lower children's IQs.

—Kaufman, Alan (2006). Assessing adolescent and adult intelligence. Hoboken, N.J: Wiley. pp. 30–31. ISBN 9780471735533.

In the mean time a POV tag on the section seems appropriate. —ArtifexMayhem (talk) 03:14, 28 April 2012 (UTC)

I've no objection to adding the info above. Heritability estimates of IQ are certainly dependent on cultural/social/family environments. All behavior/traits are phenotypes -- complex interactions of both nature and nurture. In fact, the data already presented in this section supports this (e.g., identical twins raised together vs. raised apart). No one is suggesting that since IQ is correlated with degree of genetic relatedness environmental factors are irrelevant. Memills (talk) 03:27, 28 April 2012 (UTC)

Not sure why you bring this up as evidence for POV in a section about correlations. The above figures are heritability figures. Not correlations. So it should be added to another section and not the correlations section. Academica Orientalis (talk) 03:32, 28 April 2012 (UTC)

Putting up raw stats or "correlations" without any discussion of causation is on page one of Propaganda for Dummies 3rd edition, (525 BCE). —ArtifexMayhem (talk) 03:54, 28 April 2012 (UTC)

You avoided answering my point. Also, Kaufman lists the different correlations for the different groups so he obviously thinks that they are relevant and important. Here is a commentary regarding the corelations by Kaufman in another source that we could add: "The statistics for identical twins are powerful arguments that heredity plays a key role in determining a person’s IQ, contrary to the naysayers like Kamin (1974)." Academica Orientalis (talk) 04:03, 28 April 2012 (UTC)

Your ability to cherry-pick and twist a source to fit your POV is truly astonishing. —ArtifexMayhem (talk) 04:43, 28 April 2012 (UTC)

Nothing astonishing. Just citing what Kaufman states regarding correlations. He also states, still discussing the correlations: "The big picture that emerges is that genetics plays an important role in how individuals perform on conventional IQ tests". Academica Orientalis (talk) 05:01, 28 April 2012 (UTC)

I am honestly dumbfounded re the suggestion that IQ-Kinship correlations are irrelevant to the issue of heritability of IQ. Of course it is relevant. That is why it is included in intro psych textbooks precisely as evidence for the heritability of IQ.

The objection to its inclusion here is an oxymoron. Memills (talk) 04:08, 28 April 2012 (UTC)

Aprock's statement above seems pretty clear: "In genetics, it is heritability which is considered, not bald correlations." —ArtifexMayhem (talk) 04:55, 28 April 2012 (UTC)

Aprock's statement is interesting... but it is not itself a reliable reference source.

And, he is wrong. His comment betrays a misunderstanding of the statistical measures -- heritability coefficients are based on amount of common variance, the same basis as a correlation coefficient. The only difference is that the former varies from 0 - 1 (for the amount of variance accounted for only by genetics) while the latter varies from -1 to +1 (for amount of covariance between two variables -- here, IQ scores and degree of kinship). Both statistics can be used to assess heritability. In fact, the latter could be converted into the former, at least with respect to heritability as assessed by degree of genetic kinship.

Again, as I noted above, this issue is discussed in more depth here: Regression/correlation methods of estimation of heritability. Memills (talk) 05:13, 28 April 2012 (UTC)

You cannot use wikipedia as a source for wikipedia. This has been noted several times above, and appears to be a clear instance of WP:IDIDNOTHEARTHAT. I'll again repeat, the WP:BURDEN is on you to provide a reliable source which establishes that this content merits inclusion. aprock (talk) 15:20, 28 April 2012 (UTC)

As noted above there are for example several sources by Kaufman that establishes the importance of the correlations for this topic. Regarding the relationship between correlations and heritability, to make it very simple, Falconer's simplified formula can be be used: Heritability = (correlations between identical twins - correlations between fraternal twins) x 2. (Kaufman, Alan (2006). Assessing adolescent and adult intelligence. Hoboken, N.J: Wiley. p. 29. ISBN 9780471735533.) Academica Orientalis (talk) 17:00, 28 April 2012 (UTC)

I've adjusted the highlight to illustrate the pertinent text. Heritability is computed using correlations. The correlations themselves do not represent heritability. There is nothing in that source about presenting bare correlations in lieu of computing heritability values. aprock (talk) 19:11, 28 April 2012 (UTC)

Kaufman disagrees with you since he lists the correlations and discusses them at length in a section called "Heritabiliy" in Chapter 2 of the source given above. Academica Orientalis (talk) 19:21, 28 April 2012 (UTC)

Basing inclusion on the title of a chapter section is absurd and disruptive. aprock (talk) 20:02, 28 April 2012 (UTC)

A section in chapter. Kaufman obviously thinks is the correlations are related to heritability. I have earlier noted several statements by him showing that he thinks the correlations are related and important. For example, discussing the correlations, he states "The statistics for identical twins are powerful arguments that heredity plays a key role in determining a person’s IQ, contrary to the naysayers like Kamin (1974)." Furthermore, it seems to me that it is not I who is disruptive. Introductory psychology textbooks present these correlations as do a well-known IQ expert like Kaufman. They all agree that they are very important and important evidence for the role of genetics. You seem to be using a very narrow definition of heritabiliy as a method to remove important material showing the roll of genetics for IQ. Should we create another article called for example "Genetics of IQ" for the material that the IQ experts think are important but that you want to exclude from this article? Academica Orientalis (talk) 20:08, 28 April 2012 (UTC)

No one is disputing that correlation data is presented in various sources. The problem here is that you are cherry picking raw data and inserting that section, deliberately trying to conflate correlation data with heritability. The links that you are drawing from the correlation data to heritability are not in the Kaufman book. Your claim to have shown such statements is false. aprock (talk) 20:59, 28 April 2012 (UTC)

See my last comment for what Kaufman states and other arguments. The links are indeed in and very prominently shown and discussed in Kaufman's book. Please answer the question I asked in my last post. Academica Orientalis (talk) 21:42, 28 April 2012 (UTC)

I'll repeat the bit you obviously did not read.."The problem here is that you are cherry picking raw data and inserting that section, deliberately trying to conflate correlation data with heritability." And no, we do not need yet another article that must be painfully vetted for this type of subtle POV pushing. —ArtifexMayhem (talk) 22:35, 28 April 2012 (UTC)

Please see my earlier replies. So, you are arguing there is no place anywhere in Wikipedia for arguments that IQ experts and psychology textbooks think are very important? How convenient for those disliking those arguments... And obviously not NPOV. NPOV requires that we do include the arguments from both sides and do not cherry-pick only the arguments from one side. Academica Orientalis (talk) 22:49, 28 April 2012 (UTC)

No. I am arguing against presenting raw data out of context. —ArtifexMayhem (talk) 00:53, 29 April 2012 (UTC)

Well, we can add comments like "The statistics for identical twins are powerful arguments that heredity plays a key role in determining a person’s IQ, contrary to the naysayers like Kamin (1974)" or "The big picture that emerges is that genetics plays an important role in how individuals perform on conventional IQ tests" by Kaufman. Academica Orientalis (talk) 00:55, 29 April 2012 (UTC)

Replacing the raw data dumps with secondary sourced synthesis is the appropriate way to deal with controversial topic matter. That can be done in the body of the article. This section is not supported by WP:DUE. aprock (talk) 01:13, 29 April 2012 (UTC)

Aprock, this stuff just ain't controversial.

The correlation between IQ and degree of genetic relationship is relevant to the issue of the heritability of IQ -- this is the consensus in psychological science. This article is not titled "The Heritability Coefficient" -- it is titled "The Heritability of IQ." You are beating a dead horse here. Memills (talk) 01:24, 29 April 2012 (UTC)

From Kaufman, Chapter 2, sentence two: "This chapter treats topics that are generally controversial ...". Suffice it to say, your credibility on the subject is trumped by Kaufman's. aprock (talk) 02:24, 29 April 2012 (UTC)

Is there an argument here? If so, what is it? No one had denied that this subject is controversial. Academica Orientalis (talk) 02:27, 29 April 2012 (UTC)

See the edit I was replying to: this stuff just ain't controversial. aprock (talk) 02:31, 29 April 2012 (UTC)

Your are not comparing the same thing. Make a difference regarding the controversy surrounding "Heritabiliy and malleability of IQ and attacks on the IQ construct" (chapter name) and the general agreement that the correlations between IQ and genetic closeness are relevant for to this subject. I have quoted Kaufman's views on the correlations several times above.Academica Orientalis (talk) 02:38, 29 April 2012 (UTC)

You're going to have to clarify what you've written here. It might also help if you review what was written above, since as best I can tell you haven't been paying much attention to what others are writing. aprock (talk) 02:47, 29 April 2012 (UTC)

Another quote from Kaufman from the above book. Page 27, commenting on the correlations: "But that big picture that emerges is that genetics play an important role in how individuals perform on conventional IQ test, and this role does not seem to be diminished by the role of possible confounders". Academica Orientalis (talk) 02:54, 29 April 2012 (UTC)

What "possible confounders" is Kaufman speaking of? Specifically. —ArtifexMayhem (talk) 03:26, 29 April 2012 (UTC)

Such as those proposed by Kamin (1974). Not sure why you are asking since you obviously have Kaufman's book.Academica Orientalis (talk) 12:14, 29 April 2012 (UTC)

I'm asking because I'd like to know why you find that quote worth repeating. —ArtifexMayhem (talk) 13:24, 29 April 2012 (UTC)

Actually I have not quoted that exact quote before. The earlier similar quote was Kaufman's book "IQ testing 101" (still published by an academic publisher and written by a leading IQ expert so it is a reliable source) but since you do not seem to have it I thought it best to use a source that you do have. The quote speaks for itself as a commentary on what the correlations demonstrate. Academica Orientalis (talk) 13:43, 29 April 2012 (UTC)

Yes, as already noted above [9] this sort of secondary source synthesis is generally what belongs in wikipedia, not the dump of primary data that you've inserted into the article. aprock (talk) 14:50, 29 April 2012 (UTC)

Kaufman is not a writer fond of dumping data in his books but he included these correlations in a large table as well as having a long discussion regarding the results and their implications. Kaufman is a leading expert on the subject so I think his view is more important than those of anonymous Wikipedia editors. Academica Orientalis (talk) 15:19, 29 April 2012 (UTC)

Unfortunately, his view is not included by the simple act of presenting raw data. —ArtifexMayhem (talk) 21:35, 29 April 2012 (UTC)

I have already proposed that we include Kaufman's comments. Objections? Academica Orientalis (talk) 16:45, 30 April 2012 (UTC)

This proposal was already discussed above: [10]. You're free to go ahead and replace the data dump with a neutral summary from Kaufman. aprock (talk) 16:56, 30 April 2012 (UTC)

Kaufman's comments on a table in his book showing the correlations so both the correlations and the comments are needed. Academica Orientalis (talk) 17:01, 30 April 2012 (UTC)

This is a mischaracterization of the source and an attempt to misuse source for the purpose of promoting WP:UNDUE content. Presenting his conclusions is fine. Presenting the raw data is a violation of WP:NPOV. aprock (talk) 17:35, 30 April 2012 (UTC)

It is you who are violating NPOV by wanting to exclude material found in and stated to be important in major reliable sources such as basic psychology textbooks and specialized textbooks about IQ. Furthermore, WP:PRIMARY talks about sources. It is not a prohibition of presenting numbers found in reliable sources such as major textbooks. Academica Orientalis (talk) 17:46, 30 April 2012 (UTC)

@Miradre, you already quoted that, and I responded specifically to you. My response still stands. Please review my original response. aprock (talk) 05:41, 29 April 2012 (UTC)

You have been responded to. I agree with what has been said by Memills. Please review the earlier responses. Academica Orientalis (talk) 12:20, 29 April 2012 (UTC)

Apart from the repeated efforts at obfuscation, confusion and diversion above, what part of there is "general agreement that the correlations between IQ and genetic closeness are relevant for to this subject" noted above is hard to grasp? What part of "there is consensus in psychological science" is difficult to understand? The relevance of IQ-kinship correlations to this issue is not controversial in psychological science, and literally thousands of references could be used to substantiate this assertion. Aprock has yet to provide one that argues the contrary: that the correlations between IQ and genetic closeness are irrelevant to the topic of the heritability of IQ. Memills (talk) 18:31, 29 April 2012 (UTC)

The article is certainly rife with obfuscation and confusion. —ArtifexMayhem (talk) 21:39, 29 April 2012 (UTC)

Single gene mutation causes IQ to increase by 1.29, in both copies the effect is doubled to 2.6?

I have been trying to add this for a long time:

"However, some studies suggest that even just a single gene called HMGA2 can increase IQ by 2.6 points, reducing the paradox of fairly high heritability with few actual genes found to manipulate IQ.. A single mutation of a letter from T to C in this gene raises IQ by 1.29 points, and if this happens in both copies the effect is doubled. Each mutation in each copy of the gene also increases the brain size by 0.58%. Over 21,000 people were studied for this trend to become evident, and this is one of the first peer-reviewed studies to find a single gene responsible for intelligence."

This has also appeared in well-respected secondary sources, such as New Scientist. This is also most likely not a false positive due to the large sample size and the co-dominant doubling effect of having both mutated copies of the gene. I think it should be added at least somewhere in the article, maybe in the molecular genetics section. Jaredjeya (talk) 11:05, 23 April 2012 (UTC)

Added {{reflist}} templates to Jaredjeya's comment. —ArtifexMayhem (talk) 11:51, 23 April 2012 (UTC)

The sample size in the IQ study was only 1642, which is not large for these sorts of studies. New Scientist is a non-peer-reviewed pop science magazine, not really suitable as a source for controversial claims.--Victor Chmara (talk) 11:38, 23 April 2012 (UTC)

It says N=15782 for that particular claim, but I guess it hasn't been verified enough for it to become a fact rather than an observation. Jaredjeya (talk) 16:35, 23 April 2012 (UTC)

Nope. That sample size is for the intracranial volume association. The IQ sample was an order of magnitude smaller. Quoting from the paper:

To test for pleiotropic effects of rs7294919 and rs10784502, we examined the influence of these variants on cognition in the Brisbane Adolescent Twin Study37 (N = 1642). The C allele of rs10784502, which was associated with increased intracranial volume, was also associated with increased full-scale IQ, as measured via the Multidimensional Aptitude Battery38 (effect size (β) = 1.29, standard error (S.E.) = 0.47; P = 0.0073; phenotypic correlations are shown in Supplementary Table 26). This effect was driven by performance (PIQ; β = 1.74, S.E. = 0.61; P = 0.0044) rather than by verbal subtests (VIQ; P = 0.103). rs7294919 was not associated with full-scale IQ (P = 0.139) or PIQ (P = 0.489) but showed nominal association with VIQ (effect allele: C; β = 0.126, S.E. = 0.062; P = 0.043).

No reason to report this association in the article unless further independent studies confirm it.--Victor Chmara (talk) 20:40, 23 April 2012 (UTC)

A few genes account for 8% of variance in intelligence in studied population

See [11]. Worth mentioning? Certainly not a sample representative of the general population. 8% looks impressive. Academica Orientalis (talk) 12:12, 30 May 2012 (UTC)

Not worth mentioning. Unreplicated and small sample size.--Victor Chmara (talk) 13:16, 30 May 2012 (UTC)

Unreplicated may be a reason for not mentioning it but sample size is not a reason as long as the results are statistically significant and accepted in peer-review. What is supposed to be the correct "Wikipedia sample size"? 1000? 10000? 100000? Academica Orientalis (talk) 13:22, 30 May 2012 (UTC)

There's of course no Wikipedia policy on that, but in the interests of writing a reliable article, we should not include results from studies with sample sizes so small that they are known to result in false positives. See this paper.[12].--Victor Chmara (talk) 13:29, 30 May 2012 (UTC)

That is OR. It is not up to us here to personally declare a peer-reviewed study invalid because in our own anonymous opinions there was an incorrect sample size. That judgement is already done by the experts doing the peer-review. There may be reasons for not mentioning a study but this is not one of them.Academica Orientalis (talk) 13:41, 30 May 2012 (UTC)

Also, what may be inadequate sample size in one study may not be in another based on methodology and results. Furthermore, two of the genes mentioned were also found in another study and this study thus replicates the findings. Academica Orientalis (talk) 14:55, 30 May 2012 (UTC)

I think we have to apply a little common sense, we're not required to include every study. That question of sample size versus how big an effect chance would give when there's so many factors they can select is exactly what occurred to me, and then I saw Victor Chmara's reference, thanks, to an article about it. I wonder is there any simple distillation of the criteria like fraction of standard distribution versus sample size for the number of buttons to press like you have with SNPs so if the sample size is much bigger one can feel safe and if it is smaller one starts worrying? Thanks. Dmcq (talk) 16:02, 30 May 2012 (UTC)

That the genes had an additive effect on intelligence likely reduces the risk of false-positives. False-positive genes would not have an additive effect. Academica Orientalis (talk) 16:14, 30 May 2012 (UTC)

Maybe but an estimate of the sample size needed for a study that produced this size effect would be good. Dmcq (talk) 16:19, 30 May 2012 (UTC)

Maybe but then it is not our job to be the judge regarding of if a study is correct or not. Regardless, I expect these genes to soon be studied in some other population soon which may also be more representative of the general population. 8% of total variance is a significant part of the genetic part of variance if the results are replicated in a more general population. It will be interesting to see where this goes.Academica Orientalis (talk) 21:52, 30 May 2012 (UTC)

i don't know where this fits

[http://www.wjh.harvard.edu/~cfc/Chabris2012a-FalsePositivesGenesIQ.pdf molecular genetics of psychology and social science requires approaches that go beyond the examination of candidate genes.] 178.148.233.248 (talk) 19:31, 24 November 2012 (UTC)

It is already discussed in the section "Molecular genetic investigations."--Victor Chmara (talk) 19:12, 25 November 2012 (UTC)

New York Times citation in paragraph 3 should be removed

This is just a newspaper article with no references for its claims. It shouldn't be cited. — Preceding unsigned comment added by 208.87.57.173 (talk) 01:27, 29 January 2013 (UTC)

Why the Eugenics category?

There's nothing in here about eugenics. Quite a stretch. — Preceding unsigned comment added by 208.87.57.173 (talk) 03:57, 6 February 2013 (UTC)

Well, heritability estimates are very useful for eugenicists, but there's nothing about eugenics in the article, so I'm removing the category.--Victor Chmara (talk) 08:55, 6 February 2013 (UTC)

Links to Some Good Sources on Heritability of IQ and What Heritability Means

I'm surprised to see so few links in this article to publications by Eric Turkheimer (current president of the Behavior Genetics Association, and long a very thoughtful and influential author on behavior genetics research). Other current authors (for example, Wendy Johnson and Lars Penke) have good review articles on the subject that could improve this article a lot. I'll link to some here.

Eric Turkheimer has recently been president of the Behavior Genetics Association, and he has the very kind habit of posting most of his peer-reviewed journal articles on his faculty website.[13]

Lars Penke is another, younger researcher who posts most of his publications on his personal website.[14]

An interesting review article,

Turkheimer, E. (2008, Spring). A better way to use twins for developmental research. LIFE Newsletter, 2, 1-5

http://people.virginia.edu/~ent3c/papers2/Articles%20for%20Online%20CV/Turkheimer%20(2008).pdf

admits the disappointment of behavior genetics researchers.

"But back to the question: What does heritability mean? Almost everyone who has ever thought about heritability has reached a commonsense intuition about it: One way or another, heritability has to be some kind of index of how genetic a trait is. That intuition explains why so many thousands of heritability coefficients have been calculated over the years. Once the twin registries have been assembled, it's easy and fun, like having a genoscope you can point at one trait after another to take a reading of how genetic things are. Height? Very genetic. Intelligence? Pretty genetic. Schizophrenia? That looks pretty genetic too. Personality? Yep, that too. And over multiple studies and traits the heritabilities go up and down, providing the basis for nearly infinite Talmudic revisions of the grand theories of the heritability of things, perfect grist for the wheels of social science.

"Unfortunately, that fundamental intuition is wrong. Heritability isn't an index of how genetic a trait is. A great deal of time has been wasted in the effort of measuring the heritability of traits in the false expectation that somehow the genetic nature of psychological phenomena would be revealed. There are many reasons for making this strong statement, but the most important of them harkens back to the description of heritability as an effect size. An effect size of the R2 family is a standardized estimate of the proportion of the variance in one variable that is reduced when another variable is held constant statistically. In this case it is an estimate of how much the variance of a trait would be reduced if everyone were genetically identical. With a moment's thought you can see that the answer to the question of how much variance would be reduced if everyone was genetically identical depends crucially on how genetically different everyone was in the first place."

The review article "The neuroscience of human intelligence differences" by Deary and Johnson and Penke (2010) relates specifically to human intelligence. [15]

"At this point, it seems unlikely that single genetic loci have major effects on normal-range intelligence. For example, a modestly sized genome-wide study of the general intelligence factor derived from ten separate test scores in the cAnTAB cognitive test battery did not find any important genome-wide single nucleotide polymorphisms or copy number variants, and did not replicate genetic variants that had previously been associated with cognitive ability[note 48]."

The review article Johnson, W. (2010). Understanding the Genetics of Intelligence: Can Height Help? Can Corn Oil?. Current Directions in Psychological Science, 19(3), 177-182 [16]

looks at some famous genetic experiments to show how little is explained by gene frequencies even in thoroughly studied populations defined by artificial selection.

"Together, however, the developmental natures of GCA [general cognitive ability] and height, the likely influences of gene-environment correlations and interactions on their developmental processes, and the potential for genetic background and environmental circumstances to release previously unexpressed genetic variation suggest that very different combinations of genes may produce identical IQs or heights or levels of any other psychological trait. And the same genes may produce very different IQs and heights against different genetic backgrounds and in different environmental circumstances. This would be especially the case if height and GCA and other psychological traits are only single facets of multifaceted traits actually under more systematic genetic regulation, such as overall body size and balance between processing capacity and stimulus reactivity. Genetic influences on individual differences in psychological characteristics are real and important but are unlikely to be straightforward and deterministic. We will understand them best through investigation of their manifestation in biological and social developmental processes."

Johnson, W., Penke, L., & Spinath, F. M. (2011). Understanding Heritability: What it is and What it is Not. European Journal of Personality, 25(4), 287-294. DOI: 10.1002/per.835 [17]

responds to psychologists' comments about their earlier review article on heritability. "Our target article was intended to provide background knowledge to psychologists and other social scientists on the subject of heritability. This statistic, in many ways so basic, is both extremely powerful in revealing the presence of genetic influence and very weak in providing much information beyond this. Many forms of measurement error, statistical artefact, violation of underlying assumptions, gene–environment interplay, epigenetic mechanisms and no doubt processes we have not yet even identified can contribute to the magnitudes of heritability estimates. If psychologists and other social scientists want to understand genetic involvement in behavioural traits, we believe that it is going to be necessary to distinguish among these possibilities to at least some degree. Heritability estimates alone are not going to help us do this."

Turkheimer, E. (2011). Genetics and human agency (Commentary on Dar-Nimrod & Heine, 2011). Psychological Bulletin, 137, 825-828. DOI: 10.1037/a0024306 [18]

reemphasizes the point that a heritability calculation tells us nothing about subject to environmental influences a human trait is. "That heritability depends on the population in which it is measured is one of the most frequently repeated caveats in the social sciences, but it is nevertheless often forgotten in the breach. (For example, it is nearly meaningless for Dar-Nimrod and Heine to note that 'heritability [of intelligence is] typically estimated to range from .50 to .85' [p. 805]. The heritability of intelligence isn’t anything, and even placing it in a range is misleading. Making a numerical point estimate of the heritability of intelligence is akin to saying, 'Social psychologists usually estimate the F ratio for the fundamental attribution error to be between 2.0 and 4.0.') The observation that genotypic variation accounts for 90% of the variation in height in the modern world depends on the variability of genotype and environment relevant to height. Among cloned animals with widely varying diets, body size is perfectly environmental with heritability of 0; in genetically variable animals raised in identical environments heritability is 1.0. This is no mere statistical fine point: it means that the entire project of assessing how essentially genetic traits are in terms of measured heritability coefficients is a fool’s errand."

Chabris, C. F., Hebert, B. M., Benjamin, D. J., Beauchamp, J., Cesarini, D., van der Loos, M., ... & Laibson, D. (2012). Most reported genetic associations with general intelligence are probably false positives. Psychological Science.[19]

"At the time most of the results we attempted to replicate were obtained, candidate-gene studies of complex traits were commonplace in medical genetics research. Such studies are now rarely published in leading journals. Our results add IQ to the list of phenotypes that must be approached with great caution when considering published molecular genetic associations. In our view, excitement over the value of behavioral and molecular genetic studies in the social sciences should be temperedءs it has been in the medical sciencesآy a recognition that, for complex phenotypes, individual common genetic variants of the sort assayed by SNP microarrays are likely to have very small effects.

"Associations of candidate genes with psychological traits and other traits studied in the social sciences should be viewed as tentative until they have been replicated in multiple large samples. Failing to exercise such caution may hamper scientific progress by allowing for the proliferation of potentially false results, which may then influence the research agendas of scientists who do not realize that the associations they take as a starting point for their efforts may not be real. And the dissemination of false results to the public may lead to incorrect perceptions about the state of knowledge in the field, especially knowledge concerning genetic variants that have been described as 'genes for' traits on the basis of unintentionally inflated estimates of effect size and statistical significance."

-- WeijiBaikeBianji (talk, how I edit) 19:51, 16 May 2013 (UTC)

The scholarly articles are interesting, but the personal website stuff doesn't meet citation requirements (I think). CoffeeWithMarkets (talk) 17:41, 18 May 2013 (UTC)

You might have misread that part. Looks like the sites are linked because the authors have "the very kind habit of posting most of [their] peer-reviewed journal articles on [their] website[s]". I.e., The links provided access to scholarly articles that generally satisfy WP:RS. — ArtifexMayhem (talk) 18:32, 18 May 2013 (UTC)

Yes, that is the idea. The links are to peer-reviewed publications in professional journals about genetics. Some of the scholars in the field like to bring about "open access" by posting author copies of their professional publications on their faculty or personal websites, which is a workaround to scholarly journal paywalls that is often tolerated by the publishers of the major professional journals. Most of these authors publish quite a few primary research articles too, but I am mostly linking to secondary ("review") articles that meet the Wikipedia policy on reliable sources for medicine, which too few primary research articles with preliminary research findings meet. -- WeijiBaikeBianji (talk, how I edit) 19:14, 18 May 2013 (UTC)

Oh, well, if you're linking to the scholarly publications themselves then that means that the concern about personal website stuff is not appliciable here. I'm not sure what exactly out of these articles to include, though, in terms of specific body text. This Wikipedia page here already clearly states that heritability calculations have caveats, that massive areas exist of uncertainty of how genes interact in the brain, and so on. CoffeeWithMarkets (talk) 00:25, 19 May 2013 (UTC)

Inconsistency ?

" In fact, according to the concept of regression toward the mean, parents of IQ at either extreme are more likely to produce offspring closer to the mean (or average)"

In such a case, the standard deviation of IQs should also decrease with time, which is not observed as far as I know. 212.198.146.114 (talk) 23:23, 24 August 2013 (UTC)

No, that's not what that means. Anyway, you are correct that the section with this statement needs better sourcing and more editing. I'm looking up the sources. -- WeijiBaikeBianji (talk, how I edit) 06:24, 25 August 2013 (UTC)

Time to update article per medically reliable sources

I have a lot of reliable sources at hand for checking and updating this article, and I invite fellow Wikipedians to nominate medically reliable secondary sources to use to bring this article up to date with current professional handbooks and upper-division and graduate textbooks on the article topic. I have made a few preliminary edits to the article on the basis of reliable secondary sources and I invite comments and suggestions from the rest of you to incrementally improve this article. -- WeijiBaikeBianji (talk, how I edit) 13:42, 15 October 2013 (UTC)

The article talk page has had a banner notice for years reminding editors that reliable secondary sources (rather than unreplicated primary sources) are to be preferred for editing Wikipedia articles in general, and especially for editing Wikipedia articles related to previous Arbitration Committee cases. I have at hand

Plomin, Robert; DeFries, John C.; Knopik, Valerie S. (24 September 2012). Behavioral Genetics. Shaun Purcell (Appendix: Statistical Methods in Behaviorial Genetics). Worth Publishers. ISBN 978-1-4292-4215-8. Retrieved 4 September 2013. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

(so far cited just once in this article), and I will start revising the article by using this source as the main gauge of what is current consensus on the article topic and what structure provides an organized look at the topic in encyclopedic, summary style. Of course other editors are invited to join in and update the article in light of current, reliable sources. -- WeijiBaikeBianji (talk, how I edit) 13:25, 29 October 2013 (UTC)

Good new article to read for reference.

On the Nature and Nurture of Intelligence and Specific Cognitive Abilities: The More Heritable, the More Culture-Dependent -- WeijiBaikeBianji (talk, how I edit) 13:27, 29 October 2013 (UTC)

Journal of Intelligence — Open Access Journal

Journal of Intelligence — Open Access Journal is a new, open-access, "peer-reviewed scientific journal that publishes original empirical and theoretical articles, state-of-the-art articles and critical reviews, case studies, original short notes, commentaries" intended to be "an open access journal that moves forward the study of human intelligence: the basis and development of intelligence, its nature in terms of structure and processes, and its correlates and consequences, also including the measurement and modeling of intelligence." The content of the first issue is posted, and includes interesting review articles, one by Earl Hunt and Susanne M. Jaeggi and one by Wendy Johnson. The editorial board[20] of this new journal should be able to draw in a steady stream of good article submissions. It looks like the journal aims to continue to publish review articles of the kind that would meet Wikipedia guidelines for articles on medical topics, an appropriate source guideline to apply to Wikipedia articles about intelligence. -- WeijiBaikeBianji (talk, how I edit) 21:10, 5 December 2013 (UTC)

A new possible citation

Estimation and Partition of Heritability in Human Populations Using Whole-Genome Analysis Methods174.95.171.228 (talk) 01:40, 14 February 2014 (UTC)

I came across another article yesterday that claims their ″results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence.″ [21]Lokalkosmopolit (talk) 14:54, 16 February 2014 (UTC)

Correct interpretation and use of primary research articles for editing Wikipedia text should be guided by reliable secondary sources, which has been the general Wikipedia content guideline for a long time. The talk page notice on this talk page, based on an Arbitration Committee case from 2010, draws special attention to the sourcing guidelines of Wikipedia as part of the way forward to improve the articles that have frequently been subject to edit-warring on these topics and related topics. This talk page already lists several high-quality secondary sources on heritability in general and particularly on the heritability of IQ, and the authors of those sources are well familiar with the primary research literature on the topic of this article. -- WeijiBaikeBianji (talk, how I edit) 15:11, 16 February 2014 (UTC)

Academic sources like that are far too close to the bleeding edge to be used to establish due weight. On the other hand, it's pretty well established that IQ scores have very high hereditary components. I don't think the article says otherwise, and if it give another impression it should be fixed. aprock (talk) 15:07, 16 February 2014 (UTC)

Primary research articles have been abundantly used in the article as it stands. I will familiarize myself with the Arbitration case, as I'm a new editor in this topic. Lokalkosmopolit (talk) 16:03, 16 February 2014 (UTC)

Primary research articles can and should certainly be cited in the article, especially as there is some seminal and groundbreaking work related to the topic. On the other hand primary sources which are not referred to in reliable secondary sources should be avoided. Wikipedia is not a place to publish or promote the bleeding edge of science. This is in part because the bleeding edge is preliminary, often revised, and subject to peer verification over time. Once conclusions have become well established (as the hereditary nature of IQ) the primary sources which were instrumental in exploring and developing the science are good to have. Identifying those sources should be fairly straightforward as they will be cited by the secondary sources which establish proper context. aprock (talk) 16:26, 16 February 2014 (UTC)

Sources about the broader topic of behavior genetics and the specific topic of heritability of IQ

This article is about a topic that is a subtopic in the study of behavior genetics. Wikipedia has a lot of interesting articles based on the ongoing research in behavior genetics, both in humans and in nonhuman animals. I've been reading university textbooks on genetics "for fun" since the 1980s, and for even longer I've been visiting my state flagship university's vast BioMedical Library to look up topics on human medicine and health care policy. That university has long been a center of research on human behavior genetics, being the site of a major study of monozygotic twins reared apart. On the hypothesis that better sources build better articles as all of us here collaborate to build an encyclopedia, I thought I would suggest some sources for updating the articles on behavior genetics and related topics. The Wikipedia guidelines on reliable sources in medicine provide a helpful framework for evaluating sources.

The guidelines on reliable sources for medicine remind editors that "it is vital that the biomedical information in all types of articles be based on reliable, third-party, published sources and accurately reflect current medical knowledge."

Ideal sources for such content includes literature reviews or systematic reviews published in reputable medical journals, academic and professional books written by experts in the relevant field and from a respected publisher, and medical guidelines or position statements from nationally or internationally recognised expert bodies.

The guidelines, consistent with the general Wikipedia guidelines on reliable sources, remind us that all "Wikipedia articles should be based on reliable, published secondary sources" (emphasis in original). They helpfully define a primary source in medicine as one in which the authors directly participated in the research or documented their personal experiences. By contrast, a secondary source summarizes one or more primary or secondary sources, usually to provide an overview of the current understanding of a medical topic. The general Wikipedia guidelines let us know that "Articles should rely on secondary sources whenever possible. For example, a review article, monograph, or textbook is better than a primary research paper. When relying on primary sources, extreme caution is advised: Wikipedians should never interpret the content of primary sources for themselves."

Other Wikipedians who watch the article Behavioural genetics did all of us a great favor on that article's talk page by suggesting helpful sources. In particular, User:Pete.Hurd suggested an authoritative textbook on behavior genetics, covering both the human and the animal research, and following up on his suggestion led me to several other helpful sources with similar subject cataloging in libraries.

I'll be reviewing the sources below, which I have either in full text or as sets of notes from previous readings of the sources, as I prepare to update this article with all of you looking on. I'd be delighted to hear recommendations of other sources on this article's topic that meet Wikipedia medically reliable source guidelines, as the sources listed do. The first set of sources consists of authoritative textbooks.

• Rutter, Michael (2006). Genes and Behavior: Nature-Nurture Interplay Explained. Malden (MA): Wiley-Blackwell. ISBN 978-1-4051-1061-7. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

• Bazzett, Terence J. (2008). An Introduction to Behavior Genetics. Sunderland (MA): Sinauer. pp. 241–242. ISBN 978-0-87893-049-4. Taken together, these findings suggest that about 50% of the variation seen in IQ scores is accounted for by genetics and a nearly equal percentage is accounted for by environment. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

• Kim, Yong-Kyu, ed. (25 March 2009). Handbook of Behavior Genetics. Springer. doi:10.1007/978-0-387-76727-7. ISBN 978-0-387-76727-7. Retrieved 15 December 2013. {{cite book}}: Cite has empty unknown parameter: |1= (help); Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

• Flint, Jonathan; Greenspan, Ralph J.; Kendler, Kenneth S. (28 January 2010). How Genes Influence Behavior. Oxford University Press. ISBN 978-0-19-955990-9. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

• Anholt, Robert R. H.; Mackay, Trudy F. C. (2010). Principles of behavioral genetics. Academic Press. ISBN 978-0-12-372575-2. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

• Goldman, David (2012). Our Genes, Our Choices: How Genotype and Gene Interactions Affect Behavior. Elsevier Academic Press. ISBN 978-0-12-396952-1. OCLC 773025118. Retrieved 7 November 2013. {{cite book}}: Cite has empty unknown parameters: |laysummary= and |laydate= (help); Invalid |ref=harv (help)

• Segal, Nancy L. (2012). Born Together—Reared Apart. Cambridge (MA): Harvard University Press. ISBN 978-0-674-05546-9. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

• Plomin, Robert; DeFries, John C.; Knopik, Valerie S. (24 September 2012). Behavioral Genetics. Shaun Purcell (Appendix: Statistical Methods in Behaviorial Genetics). Worth Publishers. ISBN 978-1-4292-4215-8. Retrieved 4 September 2013. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

There are many useful review articles and overview news stories from peer-reviewed scientific journals that meet the WP:MEDRS guidelines and are very useful sources for updating articles about behavior genetics (and I encourage Wikipedians to suggest others besides those listed here).

• Turkheimer, Eric; Gottesman, Irving I. (1991). "Is H² = 0 a null hypothesis anymore?". Behavioral and Brain Sciences. 14 (03): 410–411. doi:10.1017/S0140525X00070540. ISSN 0140-525X. Archived from the original on 19 April 2013. Retrieved 22 November 2013. {{cite journal}}: Invalid |ref=harv (help); Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

• Turkheimer, Eric (October 2000). "Three Laws of Behavior Genetics and What They Mean" (PDF). Current Directions in Psychological Science. 9 (5): 160–164. doi:10.1111/1467-8721.00084. ISSN 0963-7214. Retrieved 29 October 2013. {{cite journal}}: Invalid |ref=harv (help)

• Johnson, Wendy; Turkheimer, E.; Gottesman, Irving; Bouchard, Thomas (2009). "Beyond Heritability: Twin Studies in Behavioral Research" (PDF). Current Directions in Psychological Science. 18 (4): 217–220. doi:10.1111/j.1467-8721.2009.01639.x. PMC 2899491. PMID 20625474. Retrieved 21 November 2010. {{cite journal}}: Invalid |ref=harv (help)

• Johnson, W. (2010). "Understanding the Genetics of Intelligence: Can Height Help? Can Corn Oil?" (PDF). Current Directions in Psychological Science. 19 (3): 177–182. doi:10.1177/0963721410370136. ISSN 0963-7214. Archived from the original on 25 August 2013. Retrieved 15 December 2013. {{cite journal}}: Invalid |ref=harv (help); Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

• Johnson, Wendy; Penke, Lars; Spinath, Frank M. (2011). "Understanding Heritability: What it is and What it is Not" (PDF). European Journal of Personality. 25 (4): 287–294. doi:10.1002/per.835. ISSN 0890-2070. Archived from the original on 2011. Retrieved 15 December 2013. {{cite journal}}: Check date values in: |archivedate= (help); Invalid |ref=harv (help); Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

• Dick, Danielle M. (2011). "Gene-Environment Interaction in Psychological Traits and Disorders". Annual Review of Clinical Psychology. 7: 383–409. doi:10.1146/annurev-clinpsy-032210-104518. ISBN 978-0-8243-3907-4. ISSN 1548-5943. PMC 3647367. PMID 21219196. {{cite journal}}: Invalid |ref=harv (help)

Some more general reference books about genetics or behavior also touch on behavior genetics issues through book chapters.

• Spinath, Frank M.; Johnson, Wendy (2011). "Chapter 10: Behavior Genetics". In Chamorro-Premuzic, Tomas; von Stumm, Sophie; Furnham, Adrian (eds.). The Wiley-Blackwell Handbook of Individual Differences. United Kingdom: Blackwell Publishing Ltd. doi:10.1002/9781444343120. ISBN 978-1-4443-3438-8. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

• Maxson, Stephen C. (10 October 2012). "Chapter 1: Behavioral Genetics". In Weiner, Irving B.; Nelson, Randy J.; Mizumori, Sheri (eds.). Handbook of Psychology (PDF). Vol. Volume 3: Behavioral Neuroscience. John Wiley & Sons. ISBN 978-0-470-89059-2. Archived from the original on 2013. Retrieved 15 December 2013. {{cite book}}: |volume= has extra text (help); Check date values in: |archivedate= (help); Cite has empty unknown parameters: |laysummary= and |laydate= (help); Invalid |ref=harv (help)

The list above is not exhaustive, but it includes sources that are well worth a look for checking on updates of this article. Enjoy. -- WeijiBaikeBianji (talk, how I edit) 03:18, 16 December 2013 (UTC)

Now that there has been time for editors to check the sources and read through those that are readily available, this will be a productive time of year for updating the article from top to bottom for coherency, due weight on various subtopics, and referencing according to Wikipedia content policy. I look forward to seeing the next edits to article text along those lines and expect to edit some article sections from my own keyboard in the next few months. Let's all discuss here how to make the article better. -- WeijiBaikeBianji (talk, how I edit) 15:42, 20 April 2014 (UTC)

Just to collaboratively let all of you know, I plan to work on revisions of this article in a user sandbox, based on the sources mentioned on this article talk page (and on many other sources) and gradually add updated sections to this article as I have time to do that. Feel free to let me know how I'm doing as the edits proceed, and feel free to suggest aspects of this article that can be updated and how to bring this article up to good article standards of quality, at least. -- WeijiBaikeBianji (talk, how I edit) 16:40, 30 May 2014 (UTC)

Possible external links to be added

http://www.prospectmagazine.co.uk/magazine/we-cant-ignore-the-evidence-genes-affect-social-mobility/ 74.14.73.37 (talk) 06:46, 10 June 2014 (UTC)

That's not a good quality link for the external links section of this article. We should be keeping this article up to reliable source guidelines for medical articles, including the external links. -- WeijiBaikeBianji (talk, how I edit) 14:52, 10 June 2014 (UTC)

SES & Intelligence

http://www.sciencedirect.com/science/article/pii/S0160289613001682?np=y Above paper proves that IQ and SES correlation is due to genes and not environment, proving the argument of The Bell Curve. Also it is by Plomin, so is mainstream and reliable. If no one else wishes to add these edits then I shall do so. — Preceding unsigned comment added by Wajajad (talk • contribs) 18:14, 13 June 2014 (UTC)

Don't forget to sign your posts on article talk pages. I have read that paper, and the interpretation you offer is a gross misinterpretation of the paper. Moreover, the paper is a primary source about a preliminary research study (a rather well conducted study, in my opinion) and as such is not a suitable source for editing Wikipedia articles under the reliable sources content guideline here. We are here to build an encyclopedia, not to push a point-of-view agenda based on misreading primary source documents. -- WeijiBaikeBianji (talk, how I edit) 18:21, 13 June 2014 (UTC)

Your point on primary sources is duly noted, but I disagree that I misrepresented the source. Please explain that because some secondary sources corroborate my interpretation. Wajajad (talk) 18:30, 13 June 2014 (UTC)

Please show us a reliable secondary source on the point at issue. -- WeijiBaikeBianji (talk, xhow I edit) 18:36, 13 June 2014 (UTC)

You can easily searxh for academic responses to Plomin's research through citations.Wajajad (talk) 18:42, 13 June 2014 (UTC)

Heritability of IQ found to be *not* affected by SES

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030320

Above study by Robert Plomin indicates that SES doesn't modulate heritability of IQ, and in fact, race doesn't modulate heritability of IQ either. More sources are found here: http://jaymans.wordpress.com/2014/04/15/more-behavioral-genetic-facts/ All sources are high quality and warrant inclusion into this article.74.14.73.162 (talk) 08:04, 17 July 2014 (UTC)

The Plomin study is already discussed in the article.--Victor Chmara (talk) 12:30, 17 July 2014 (UTC)

It's a primary source. -- WeijiBaikeBianji (talk, how I edit) 15:03, 17 July 2014 (UTC)

It is a primary source that is contradicted by a number of other primary sources.User:Maunus ·ʍaunus·snunɐw· 15:39, 17 July 2014 (UTC)

It's a secondary source, a review and analysis of all the previous studies74.14.22.228 (talk) 01:59, 18 July 2014 (UTC)

Why no article for "Genetics of intelligence"?

Genetics of aggression, Genetics of obesity, Psychiatric genetics, Genetics of gender, Genetics of aging, Genetics of social behavior, yet no separate article for Genetics of intelligence.

Heritability takes a value ranging from 0 to 1; a heritability of 1 indicates that all variation in the trait in question is genetic in origin and a heritability of 0 indicates that none of the variation is genetic.

No.

Heritability is not the same as genetics, and IQ is not the same as intelligence. Even specialists occasionally ignore the reality of de novo mutations. There are other factors to consider, too, such as gene expression and epigenetics. The article mentions, for example, statistical reliability concerning the method of measurement, namely the tests. 213.109.230.96 (talk) 10:26, 20 June 2014 (UTC)

I'm not entirely sure, but it looks like unsigned comments here may be confusing who said what. It's plain enough that in the current structure of Wikipedia, this article is the article about the genetics of human intelligence, about both what genetics does and what genetics doesn't do in relation to IQ. (By the way, the current Coursera course on human behavior genetics, free and online for everyone around the world who has Internet access, is an excellent introduction to the topic of this article, recommending some very helpful readings and presented by a professor who is an acknowledged expert on the topic. I will be revising this article in light of what that course has taught people all around the world, and I encourage all of you to access the course while it is still live in its first term online.) -- WeijiBaikeBianji (talk, how I edit) 16:07, 20 June 2014 (UTC)

Sorry if it looks confusing. I decided to break it into paragraphs. A reply would be indented; the quotation is indented automatically. Feel free to edit to correct the stylistic issues. Now, if this article covers not just heritability, but also genetics in general, then why not name it accordingly? But I don't think it does. Except for the lead section mention that intelligence is a polygenetic trait, the article is concerned with heritability only. Otherwise, why not mention, say, individual genes? For example, genes associated with aspects of attention or memory (remember that memory is integral to learning, both of knowledge and of paractical skills). The NPTN gene was linked this year to cortical thickness and performance in intelligence tests. Another obstacle is that regular IQ tests are the only means of measuring intelligence this article focuses on, so it makes less sense to call it "X of intelligence" than "X of IQ." Thank you for the recommendation. 213.109.230.96 (talk) 22:24, 9 July 2014 (UTC)

What means of measuring intelligence other than IQ-type tests are there? In any case, the article is called Heritability of IQ. The fact is that the molecular genetic basis of cognitive ability is currently almost completely unknown. (The same applies to most other complex traits, too, of course.) Reported associations between IQ and specific genetic variants have proven very difficult to replicate. This is discussed in the section "Molecular genetic investigations". The primary source of knowledge on the genetics of intelligence is therefore the extensive research on its heritability. I don't think there's a need for an article on the molecular genetics of intelligence at this point because we know very little about that. In contrast, we know lots about the heritability of intelligence, and what little we know about specific genetic variants can be discussed in this article.--Victor Chmara (talk) 09:55, 10 July 2014 (UTC)

And the definition of heritability in the article is correct, and the IP user's objections make no sense. Heritability indicates the extent to which DNA sequence variation influences phenotypic variation, regardless of the pathways through which it takes place. Unreliability of the tests is a non-genetic source of phenotypic variation, and behavioral genetic methods correctly identify it as such.--Victor Chmara (talk) 10:04, 10 July 2014 (UTC)

"The fact is that the molecular genetic basis of cognitive ability is currently almost completely unknown. (The same applies to most other complex traits, too, of course.)" Sure. The question, then, has to be asked: why the asymmetry? Intelligence is not the only complex trait whose molecular genetic basis is poorly understood, as you've pointed out, so why do we see Genetics of aggression, Genetics of social behavior, etc., yet no Genetics of intelligence? Maybe we don't need a separate article after all, but the question is open. It's not merely rhetorical. 213.109.230.96 (talk) 02:29, 11 July 2014 (UTC)

"What means of measuring intelligence other than IQ-type tests are there?" Standard IQ tests are a fairly homogenous class. They are static, while computer-based tests, for instance, allow for more dynamic, interactive options in cognitive tests, such as n-back. IQ tests are designed to assess reasoning abilities, visuospatial and linguistic-mathematical, while accepted definitions of intelligence encompass also attention and memory, and some go even further. Intelligence tests can be psychometric or biological. Neuroimaging intelligence testing is still in its early days, but it's a promising prospect. Additionally, encephalization quotient (EQ) is relevant for cross-taxon measurements of intelligence, as imperfect as it is. 213.109.230.96 (talk) 02:29, 11 July 2014 (UTC)

"And the definition of heritability in the article is correct." The definition of heritability is correct, but the implied definition of "genetic" is not. Needless to say, genetics is more than just heritability. I've heard the argument that schizophrenia cannot be fundamentally genetic because most schizophrenics don't even have any family history of schizophrenia, but that argument ignores the fact that de novo mutations are often involved in the disorder. That argument also fails to account for pleiotropy: genes associated with other disorders may be involved in schizophrenia, seeing that family members of schizophrenics have higher rates of certain other disorders, not just of schizophrenia itself. Besides the word "hereditary," another adjective oft-confused with "genetic" is "inborn" -- or "congenital," if you will -- which excludes postnatal modification of gene expression and postnatal genetic code alterations. 213.109.230.96 (talk) 02:29, 11 July 2014 (UTC)

I'm not categorically opposed to the title you propose, but there are several reasons that support the current title. There is more research on the heritability of IQ than any other trait. There are not just univariate estimates of ACE components, but lots of studies of possible moderators of heritability (age, SES), studies on the heritability of different cognitive abilities and genetic correlations between them, studies of the longitudinal stability of genetic effects, etc. Any article on the genetics of IQ is going to be overwhelmingly about heritability. Most other traits have not been studied in such detail using behavioral genetic methods. The molecular genetic basis of many of those other traits you mentioned is also better known, partly because cross-species comparisons are more straightforward and animal models can be used.

There are adaptive IQ tests, but while they have some benefits such as greater reliability, they are not different from traditional tests in any fundamental sense. Many IQ test batteries have subtests that assess other abilities than the ones you mention. For example, memory tests such as digit span have been traditionally included in many batteries. The Woodcock-Johnson battery is designed to assess all the abilities recognized by the CHC theory. Psychometric theory predicts that all cognitive abilities are related to each other in a hierarchical fashion.

Neuroimaging cannot currently be used to test intelligence. The article Neuroimaging intelligence testing is badly named as it's really about correlations between IQ scores and neurobiological variables rather than about a new testing modality. Biological variables like encephalization quotient cannot be used as intelligence tests, either, certainly not within a species.

Heritability is a population level statistic. The etiology of a disease like schizophrenia in a particular individual is not in the purview of behavioral genetics. Behavioral geneticists have established that the incidence of schizophrenia increases with relatedness, e.g., if your cousin has schizophrenia, you have a 2x risk compared to the base rate, but a 50x risk if your MZ twin has it, which indicates the influence of genetics. De novo mutations are incorporated in the definition of heritability, and if a particular method of estimating heritability does not take their influence into account, the problem is with that method, not with the definition of heritability. Any estimate of heritability may be biased due to practical reasons, but that does not mean that the concept of heritability is somehow faulty. Pleiotropy can be directly assessed with behavioral genetic methods.--Victor Chmara (talk) 11:54, 11 July 2014 (UTC)

Makes sense. I'm quite satisfied with your answer and believe the subject is exhausted.

The only thing left to comment is that maybe I haven't made it clear enough why I keep talking about de novo mutations. It was supposed to be an example of why "heritable" is not the same as "genetic." The sentence cited from the article states that if a trait is 100% heritable, it's 100% genetic. But that can't be right, because heritability is influence by both genetic and non-genetic factors. And, as for de novo mutations, suppose for the sake of example that a trait called trait X is 10% genetic. De novo mutations could influence the variance, making the heritability to be <0.1, but that wouldn't contradict the reality that trait X is 10% genetic.

On a side note, a study on the heritability of intelligence in chimpanzees has been published two days ago, attracting a fair amount of attention. Should it at least be mentioned in the article? 213.109.230.96 (talk) 15:25, 12 July 2014 (UTC)

Primary research articles are simply not good sources for Wikipedia (which is an encyclopedia, not a review of current research) by Wikipedia content guidelines. Especially a paper on chimpanzee intelligence published just two days ago is not a good source for this article, even though it may be an interesting read. (I have downloaded thousands of articles about human intelligence in the last few months, but as I read along, my general impression is that most Wikipedia articles will improve the most by removing, rather than adding, citations to primary research articles. Review articles and textbook and handbook chapters are really the better sources for Wikipedia in general, and especially for articles about human intelligence on Wikipedia.) -- WeijiBaikeBianji (talk, how I edit) 18:58, 12 July 2014 (UTC)

De novo mutations in the germline are included in the estimation of heritability, at least in principle (e.g., MZ twins have the same mutations). In contrast, somatic de novo mutations, to the extent that they cause phenotypic differences, are counted as environmental influences, and I think that's exactly as it should be. BTW, it is not meaningful to say that trait X is "10 percent genetic". You should say that the variance in trait X is 10 percent genetic, or that the heritability of trait X is 10 percent.--Victor Chmara (talk) 20:53, 14 July 2014 (UTC)

• I agree with the original poster that it would be useful to have separate articles on genetics and intelligence and heritability of IQ. The genetics article would go into the genetic evidence, describing specific genes that have been linked to intelligence. This is an empirical topic showing actual causal links between genes and cognition. Heritability of IQ is a different topic, basically about a correlation between two statistical artefacts. User:Maunus ·ʍaunus·snunɐw· 22:52, 16 July 2014 (UTC)

• In practice, as Victor has correctly pointed out, most human behavior geneticists investigating the genetics of human intelligence keep coming back to heritability studies, because so far GWAS and other techniques have not been very informative, even with astoundingly large sample sizes. The individual gene effects are plainly quite small, with hundreds of genes involved. -- WeijiBaikeBianji (talk, how I edit) 23:22, 16 July 2014 (UTC)

Correct, of course. But there are also lots of genes identified that play a role in intelligence, especially outside of the normal range. I think the heritability evidence and genetic evidence are two different things that can and should be kept apart, at least to the degree of having each its own article, though they will likely overlap some. As one of my favorite geneticists like to say "Conclusions about genetics require genetic evidence", and heritability evidence is not genetic.User:Maunus ·ʍaunus·snunɐw· 23:49, 16 July 2014 (UTC)

Heritability and psychometric intelligence are "artifacts" in the same sense that, for instance, gravity and genes are artifacts, that is, they are theoretical constructs backed up by tons of evidence. If a GWAS identifies variants associated with a phenotypic trait, it is also just a "correlation between two statistical artifacts". Molecular genetics has so far been very bad at explaining polygenic traits, and our understanding of the genetics of most traits comes from behavioral genetics. The suggestion that genetic explanation is possible only at the molecular level is, of course, silly.

The genetic basis of organic intellectual disability is pretty well understood because the various syndromes are usually Mendelian traits. The proper place to discuss this is the Intellectual disability article. In contrast, we know basically zilch about the genetics of intelligence in the normal range, so it's quite sufficient to mention what little we know in this article. In a few years, the situation may be different.--Victor Chmara (talk) 12:05, 17 July 2014 (UTC)

It is rather bold to consider heritability and psychometric intelligence to be constructs of the same degree as physical laws, there certainly is no consensus about such a view in any of the disciplines involved in researching them. In fact I would say that this idea is a lot more silly than the idea of requiring molecular evidence for making conclusive statements about the relation between genes and phenotypes. I agree of course that GWAS is also not actual genetic evidence, but rather a correlation between correlations. You may be right however that there is not enough actual genetic evidence to have a separate article on that. User:Maunus ·ʍaunus·snunɐw· 15:43, 17 July 2014 (UTC)

The conclusions of social science may never reach the level of certainty associated with physical laws, but the point is that the nature of theoretical constructs in social science is not different from those in the physical sciences or the life sciences. What you call "statistical artifacts" is how scientific explanation in general works. Our understanding of cognitive abilities compares favorably with our understanding of, for example, large swathes of medicine (e.g., psychiatry), and heritability is a key concept in evolutionary genetics because it determines the response to selection.--Victor Chmara (talk) 09:58, 18 July 2014 (UTC)

It appears that we have contradictory views regarding epistemology and the philosophy of science. I do think that theoretical constructs in social sciences are fundamentally different from those in physical and life sciences in a number of important ways. I realize that clinical approaches in many fields proceed on this kind of evidence, but it does not fall under the umbrella of what I call "knowledge" unless we actually understand the causal mechanics of how it works. Sure trial and error and statistical methods are part of the scientific method, but they do not produce knowledge in an of themselves. Anyways, it doesnt matter at this point since we agree on the content aspect.User:Maunus ·ʍaunus·snunɐw· 02:15, 19 July 2014 (UTC)

SNPs found in GWAS confirmed to affect IQ

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0100248#pone.0100248.s005

Above paper proves certain SNPs found through GWAS indeed associated with cognitive ability. This development in genetic causation of IQ must not go unmentioned in this article.74.14.73.163 (talk) 03:18, 29 July 2014 (UTC)

Please see WP:PRIMARY. Specifically, "Do not analyze, synthesize, interpret, or evaluate material found in a primary source yourself; instead, refer to reliable secondary sources that do so." — ArtifexMayhem (talk) 08:31, 29 July 2014 (UTC)

Common genetic variants associated with cognitive performance identified using the proxy-phenotype method

http://m.pnas.org/content/early/2014/09/05/1404623111 New source from Plomin and Visscher labs about gene variants behind IQ. New citation for this article.74.14.75.158 (talk) 19:46, 11 September 2014 (UTC)

If (and only if) this preliminary primary research finding is taken up and discussed in reliable secondary sources, then we will have something to add to this article. Meanwhile, there are a lot of good comments from Plomin and his co-authors in their authoritative textbook and from Visscher and his co-authors in their various review articles that have never been used in this article at all. That's regrettable. That's why I recommend a steadily growing list of reliable, secondary sources on intelligence in user space for the convenience of all Wikipedians. -- WeijiBaikeBianji (talk, how I edit) 19:58, 11 September 2014 (UTC)

[22] The new study also was covered in Nature News (a secondary source). 36.250.89.27 (talk) 21:30, 11 September 2014 (UTC)

Yep. "'With effects this small, the chances that they represent false positives are vastly increased,' says Kevin Mitchell, a neurogeneticist at Trinity College Dublin who says he was decidedly underwhelmed by the study." That's the problem with GWAS and IQ. -- WeijiBaikeBianji (talk, how I edit) 21:40, 11 September 2014 (UTC)

Addition of graphic

Added graph over heritability over lifespan from study "Behavioral Genetics of Cognitive Ability".. Revert if you disagree...MicroMacroMania (talk) 11:27, 13 September 2014 (UTC)

Why that source, and why that graphical representation of what is said in the source? I'll boldly revert while awaiting your rationale. -- WeijiBaikeBianji (talk, how I edit) 11:50, 13 September 2014 (UTC)

The graph is excellent and frequently used in reliable sources, but what is its copyright status? A good source for this article is this new meta-analysis of longitudinal determinants of IQ.--Victor Chmara (talk) 12:37, 13 September 2014 (UTC)

In what way is it excellent? The graph wasn't even referenced in the body of the article. In fact, it appears to actively contradict content in the article. The article mentions a heritability range of 40-80%. The figures looks like about 55% for 16-20 year olds, and the article quotes 85% for 18 year olds. aprock (talk) 17:02, 13 September 2014 (UTC)

Well, it could be referenced. The estimate of 85% is not from a meta-analysis but from one big Dutch study. In contrast, the graph is based on the aggregated results of dozens of different studies. Many studies are preferable to just one study.--Victor Chmara (talk) 12:23, 14 September 2014 (UTC)

Generally agree, it would probably make sense to replace the single study summary with a summary of the aggregated data. aprock (talk) 15:53, 14 September 2014 (UTC)

Yep, that's why current textbooks make for better sourcing than journal articles from two decades ago. -- WeijiBaikeBianji (talk, how I edit) 17:08, 14 September 2014 (UTC)

I made the graph in the same manner of the one from: THIRTY YEARS OF RESEARCH ON RACE DIFFERENCES IN COGNITIVE ABILITY... Which site the same study. MicroMacroMania (talk) 17:10, 13 September 2014 (UTC)

Well I choose to represent it in the same manner as done in the study: THIRTY YEARS OF RESEARCH ON RACE DIFFERENCES IN COGNITIVE ABILITY. By Athur Jensen J. Philippe Rushton. I Dont see how I represented it wrong. It shows the heritability by agy over life span. I painted the whole graph and represented the data from the study correctly. The license copyright is under creative commons 3.0. That is what is commonly used siting all other studies here on wikipedia and if my understanding is right, same goes for that graph.MicroMacroMania (talk) 13:29, 13 September 2014 (UTC)

You cannot escape copyright issues by drawing a graph that is identical to the original.--Victor Chmara (talk) 12:29, 14 September 2014 (UTC)

Victor makes the good point that Wikipedia has strict rules about copyright and use of nonfree media. I personally am still investigating the issue of how to obtain a graphic representing the findings of the classic (and often replicated) study by Cooper and Zubek (1958), findings that are mentioned in most of the standard textbooks (and which would certainly be relevant for this article), but I try to be cautious about use of graphics in light of Wikipedia policies. Graphics should be very well cited to their underlying sources and their use in articles should be carefully explained with narrative text (again, based on reliable, secondary sources) to respect copyright and core Wikipedia policies, and to avoid misleading readers. -- WeijiBaikeBianji (talk, how I edit) 14:20, 14 September 2014 (UTC)

a good external link

http://www.nature.com/mp/journal/vaop/ncurrent/full/mp2014105a.html

Above article is by Ian J. Deary and Robert Plomin and is an excellent inclusion as an external link.74.14.75.158 (talk) 17:14, 16 September 2014 (UTC)

If we use it as citation, we can use it to cite the fact that we live in an IQ meritocracy and that SES is correlated with IQ for that reason.74.14.75.158 (talk) 18:08, 16 September 2014 (UTC)

It's an interesting research article (labeled, fairly, I think, by the editors as a "review article") by well informed authors, but it is better for working into this article after careful reading alongside additional secondary sources, not as a suitable external link for this article, per WP:EL. Your summary of the article is not balanced, and I note that the article's abstract does not summarize the conclusions in the same way. -- WeijiBaikeBianji (talk, how I edit) 19:13, 16 September 2014 (UTC)

It is a review article, and therefore a secondary source, it is not a primary research article. It is a suitable source for this article. But no we can not use to cite those ideas because that is not what the article says.User:Maunus ·ʍaunus·snunɐw· 19:11, 16 September 2014 (UTC)

I think you're mistaken about that, but I am open to different views regarding this article. I would like to know what can be extrapolated from this article.74.14.75.158 (talk) 19:55, 16 September 2014 (UTC)

Wikipedia is not here to extrapolate but to summarize.User:Maunus ·ʍaunus·snunɐw· 22:17, 16 September 2014 (UTC)

I am aware, but what's wrong with my summary of the main points of the above article and how do you suggest we make use of this article?74.14.75.158 (talk) 02:35, 17 September 2014 (UTC)

The article summarizes five findings regarding the relation between IQ and genetic differences, none of them state that we live in an IQ meritocracy or that SES correlates with IQ for that reason. The fifth of the five findings is simply that there are correlations between genes, IQ and SES. The authors then propose the hypothesis that genes may have a partly causal effect on this correlation. (They write: "Finding that, in twin and GCTA studies, the same genes influence intelligence and social epidemiologists’ ‘environmental’ variables of education, social class, and height can enlighten research in health and social inequalities. It leads to the hypothesis that GPS scores for intelligence might contribute to health outcomes and mortality, and that these might account for some of the associations between education and class and mortality.") Proposing a hypothesis is a very different exercise than stating a fact. The main points of the article however are about the relation between genetic population structure and intelligence differences, and have nothing to do with the socioeconomic domain. The paper would be a find source for those findings such as the heritability question. User:Maunus ·ʍaunus·snunɐw· 14:48, 17 September 2014 (UTC)

Continuing on the IQ meritocracy train of thought, Plomin et al. have published a study that demonstrates that SES has no moderation on IQ at all, so I think we are justified for having it in the article. Also, I think there are problems with citing Turkheimer in this article to attempt to disprove IQ meritocracy, the original Turkheimer study showing this effect was pretty low quality. The data were old (from the 1950s as I recall), so there's no reason to think the results still hold today given the large social changes in the US since then. More importantly, it was underpowered for the effect it was trying to detect. It takes a lot more statistical power to detect GxE interactions than to detect G+E main effects, and consequently if an underpowered study does find such effects it's quite likely that it's just a false positive. More here.74.14.75.158 (talk) 19:57, 19 September 2014 (UTC)

The recent review by Nisbett, Flynn et al. states it as a clear and well supported finding that heritability of IQ varies between SES groups. Our personal evaluations of a study's strength are irrelevant, we rely on how it is evaluated in the literature. IF you know of reliable secondary sources that report on Plomin's study then we can see whether to include it. And by the way you seem to be, again, misrepresenting the study you refer to. Plomin et al, demonstrate that genetic effects on IQ variation are equally strong in both high and low SES groups, BUT that variance is greater in low SES groups which they argue is caused by environmental effects, specifically experience. This is entirely compatible with the view that heritability figures vary by SES group, with lower heritability for low SES. In fact the authors state as much in the conclusion, namely when they point out that it looks as if environmental factors are more influential in low SES groups. User:Maunus ·ʍaunus·snunɐw· 21:30, 19 September 2014 (UTC)

Do you have any sources besides a point-of-view web discussion forum to guide your understanding of the current professional research literature? -- WeijiBaikeBianji (talk, how I edit) 22:06, 19 September 2014 (UTC)

The effects found in the Turkheimer study haven't been replicated in any other studies, and we have no reason to refer to it as conclusive at all. 74.14.75.158 (talk) 21:16, 20 September 2014 (UTC)

Nisbett, Flynn et al 2012 review the Turkheimer study and all the attempted replications evaluating them as "mixed", they specifically state that Rushton and Jensen misrepresent Nagoshi and Johnsons study as a failure to replicate when in fact it is not, and they conclude that its findings are solid. So yes we do have a reason to refer to it as such, because that is what reliable secondary sources do. The Nisbett, Flynn et al. paper should be cited in the article.User:Maunus ·ʍaunus·snunɐw· 21:22, 20 September 2014 (UTC)

Citation related to defense from criticism of Behavior Genetics

http://onlinelibrary.wiley.com/doi/10.1111/1745-9125.12049/abstract The above link is a comprehensive rebuttal of all detractors of behavior genetics and warrant inclusion in this article and related ones.76.66.130.161 (talk) 22:16, 30 September 2014 (UTC)

Get real. You just heard about the abstract on some blog and haven't even read the full article yet. In your own words, what do the best available secondary sources written for advanced students or for current practitioners say about the issue of "heritablity" estimates and what we can understand about IQ test scores from those estimates? -- WeijiBaikeBianji (talk, how I edit) 02:49, 1 October 2014 (UTC)

::Please don't post these off-topic comments, Weiji. I have read the full article. Everything else you write above is totally inscrutable, please make points relevant to the above source.76.66.130.161 (talk) 05:10, 1 October 2014 (UTC)

The topic of the article isn't heritability of IQ, and it is a primary source. Not in any way appropriate for the article. aprock (talk) 13:39, 1 October 2014 (UTC)

It's not a primary source, it's a review of previous studies on the assumptions behind the classical twin design. It could have some use in this article.--Victor Chmara (talk) 13:46, 1 October 2014 (UTC)

It's an interesting summary of some arguments made from one point of view about twin studies, specifically related to a previous article by other authors in the field of criminology, so, yes, it is a useful overview of current heritability studies related to criminology, but a more on-point review article by more eminent authors (which just might be an article that has been removed or very badly misrepresented by people on the "same side" of the issue as the OP here) is Johnson, Wendy; Turkheimer, E.; Gottesman, Irving; Bouchard, Thomas (2009). "Beyond Heritability: Twin Studies in Behavioral Research" (PDF). Current Directions in Psychological Science. 18 (4). Association for Psychological Science: 217–220. doi:10.1111/j.1467-8721.2009.01639.x. PMC 2899491. PMID 20625474. Archived from the original on 29 June 2010. Retrieved 21 September 2014. {{cite journal}}: Invalid |ref=harv (help); Unknown parameter |deadurl= ignored (|url-status= suggested) (help). The reference I'm mentioning here is indisputably a review article, and considerably more related to IQ. -- WeijiBaikeBianji (talk, how I edit) 14:35, 1 October 2014 (UTC)

And again, striking through sock of a banned user, one of the R&I farm.[23]. Dougweller (talk) 08:01, 3 October 2014 (UTC)

Further sources for correlation of IQ with success

http://www.sciencedirect.com/science/article/pii/S0160289606000171 http://m.cdp.sagepub.com/content/19/6/339 Also relevant to the above discussion on sources for meritocracy are these two sources demonstrating the high correlation of high academic and career success with cognitive ability.

Another — slightly irrelevant to this line of discussion — source relates to the common genetic variants proven to be causal to cognitive performance: http://m.pnas.org/content/111/38/13790.abstract

Wajajad (talk) 05:56, 6 October 2014 (UTC)

With this following source, we can cite that in UK lower SES doesn't moderate IQ heritability in any fashion, no G×E in there http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0030320#pone-0030320-g007

Wajajad (talk) 09:02, 6 October 2014 (UTC)

Here's yet another source,reaffirming the importance of genetics in education: http://m.pnas.org/content/early/2014/10/02/1408777111.abstract Wajajad (talk) 03:01, 7 October 2014 (UTC)

Fletcher, Richard B.; Hattie, John (11 March 2011). Intelligence and Intelligence Testing. Taylor & Francis. p. 37. ISBN 978-1-136-82321-3. Retrieved 31 August 2013. While important, general intelligence (or 'g'), as measured by IQ tests, is only one of the attributes we value in our society. Arthur Jensen (1998: 356), for example, has underlined that the expression of intelligence in any person's life and in the character of a society depends on other factors, equally important, that are independent of 'g'. He goes on to say that it is the interaction between general intelligence and these other factors that accounts for much, probably most, of the enormous variance in the visible aspects of what most people regard as worldly success. Success in life is not at all related to a single factor; success has many dimensions and IQ plays an important part in only some of them. There are many other factors that can sit along with, and at times surpass, IQ and these certainly are valued just as much as IQ. These include conscientiousness, integrity, sustainability, effort, commitment and seeking to be self-learners, among other attributes. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help)

Seeing your edit summary above, how is this irrelevant? — Preceding unsigned comment added by Wajajad (talk • contribs) 06:35, 7 October 2014 (UTC)

Gregory Clark as a citation?

We can cite Gregory Clark to demonstrate that most societies have been meritocracies based on ability and thus we have the hierarchies we see today?76.66.130.161 (talk) 01:21, 24 September 2014 (UTC) His books A Farewell to Alms and The Son Also Rises are pertinent to this article.76.66.130.161 (talk) 01:32, 24 September 2014 (UTC)

There is a huge literature on this, but I'm not sure it belongs to this article. The issue goes back at least to Herrnstein's famous 1971 article (I have not been able to find it anywhere, so I haven't read it). His argument is now called "Herrnstein's syllogism". The Bell Curve explores the topic at length, and later studies also show that within families the smarter siblings tend to do better. This cannot be explained by shared environment since the siblings share this.

Useful references: Herrnstein, R. J. (1971). IQ Atlantic Monthly. September (228: 7), 43-64., Herrnstein, R. J. (1973). IQ in the Meritocracy. Boston: Little, Brown., Herrnstein, R. J., & Murray, C. (1994). Bell curve: Intelligence and class structure in American life. Simon and Schuster., Murray, C. (2002). IQ and income inequality in a sample of sibling pairs from advantaged family backgrounds. American Economic Review, 339-343. There are a bunch of modern behavioral genetic studies showing that there is a genetic correlation between IQ and socioeconomic measures, which is predicted by the meritocracy model. Perhaps the first study of this kind was Rowe, D. C., Vesterdal, W. J., & Rodgers, J. L. (1998). Herrnstein's syllogism: Genetic and shared environmental influences on IQ, education, and income. Intelligence, 26(4), 405-423. Maciej Trzaskowski, Nicole Harlaar, Rosalind Arden, Eva Krapohl, Kaili Rimfeld, Andrew McMillan, Philip S Dale, and Robert Plomin. Genetic influence on family socioeconomic status and children’s intelligence. Intelligence, 42:83--88, 2014. Riccardo E Marioni, Gail Davies, Caroline Hayward, Dave Liewald, Shona M Kerr, Archie Campbell, Michelle Luciano, Blair H Smith, Sandosh Padmanabhan, Lynne J Hocking, et al. Molecular genetic contributions to socioeconomic status and intelligence. Intelligence, 44:26--32, 2014. Clark's book is mostly about social mobility, not meritocracy as such. Deleet (talk) 02:39, 26 September 2014 (UTC)

These are all excellent articles, Emil. What edits do you suggest we make to the article using these? I would say editing the "Heritability and socioeconomic status" to represent these recent studies and the mainstream view that Turkheimer 2003 has been debunked by current studies.Wajajad (talk) 05:10, 8 October 2014 (UTC)

Is that relevant to debate of heritability of IQ? Not that it is not an interesting info, though also mentioned in the bell curve. MicroMacroMania (talk) 08:59, 24 September 2014 (UTC)

I dont think Clark is a good source for anything really, except for his own opinion. Have you seen his work referred to in any actual scientific works? In any secondary summaries? I haven't. On the contrary I've seen it be excruciatingly criticized by economists. The only people I've seen it promoting it are members of the small clique of Bell Curve proponents who have been pushing the same political agenda of social Darwinism for the past 25 years. Most of the promotion has been through the blogosphere around Steve Sailer. But I dont see it being taken seriously outside of that small network of politically conservative scholars.User:Maunus ·ʍaunus·snunɐw· 21:25, 24 September 2014 (UTC)C)

Struck through edits by yet another now blocked sock. Dougweller (talk) 07:58, 3 October 2014 (UTC)

New GCTA of cognitive ability

Link PDF

A reliable source. We can include it to show that cognitive ability / intelligence differences can be accounted for (29%) by specific SNPs. This data is reliably replicated. 74.14.49.84 (talk) 14:21, 23 February 2015 (UTC)