Talk:Intelligence quotient/Archive 6

Archive 1

←

Archive 4

Archive 5

Archive 6

Archive 7

Archive 8

"Criticism" by Binet

The test created by Binet is very different from today. He only looked at children, the test was more of a knowledge or skill test, it produced a mental age instead of normalized scores, and so on. An enormous amount of development and research have been done since. As such this "criticism" is only of historical interest and should be removed. Acadēmica Orientālis (talk) 11:33, 6 February 2012 (UTC)

Poor use of mathematical and statistical concepts

This article, unfortunately, conflates the concepts of "mean", "median" and "mode." Specifically, in the introduction, a 100 IQ is described as being the "average (or mean)" score on a standardized test designed to measure IQ. Later in the article, a 100 score is presented as being the median score. And in other parts a 100 IQ score is described as the most usual score in a population. The problem: the median score is not the same as the mean score, nor the mode score as usually understood. Worse yet, the concepts of "median" and "mode" scores better approximate the ordinary concept of the average, while in the introduction, the "average" is described as the arithmetic mean (which departs from the actual scoring of IQ tests - sorry, no references - this is a rushed commentary). The mean (the arithmetic mean) is basically the sum of the scores of a sample, divided by the number in the sample. The median is the score of an individual in a population, where half of the rest of the population scores above, and the other half scores below. Finally, the mode score is the most likely score in a population. None of these concepts is equivalent to the other, but the prose frequently conflates these concepts. In short, this article needs to get these concepts straight, and get it straight what a 100 IQ means.

174.29.213.67 (talk) 11:51, 5 March 2012 (UTC)

They are all exactly the same for IQ because of the way it is set up. Dmcq (talk) 13:41, 5 March 2012 (UTC)

While using all three terms without further explanation is confusing, you are correct that with respect to normal distributions the mean, median, and mode are identical by formulation. FTA:

"The parameter μ is at the same time the mean, the median and the mode of the normal distribution."

Perhaps this might be worth pointing out here. Bakkster Man (talk) 15:46, 5 March 2012 (UTC)

The question is NOT whether we need a lesson in elementary statistics, but how the test makers define their parameters (in this case IQ). To wit:

The Stanford-Binet Intelligence Scales: Fifth Edition

The fifth edition of the Stanford-Binet (SB5; Roid, 2003a) was designed for administration

to assessees as young as 2 and as old as 85 (or older). The test yields a number

of composite scores, including a Full Scale IQ derived from the administration of ten

subtests. Subtest scores all have a mean of 10 and a standard deviation of 3. Other composite

scores are an Abbreviated Battery IQ score, a Verbal IQ score, and a Nonverbal

IQ score. All composite scores have a mean set at 100 and a standard deviation of 15.

Source: Psychological Testing and Assessment: An Introduction to Tests and Measurement 7th Edition

Cohen−Swerdlik

McGraw-Hill Copyright ©2009 by The McGraw−Hill Companies, Inc. All rights reserved

http://www.primisonline.com

N0w8st8s (talk) 09:58, 5 April 2012 (UTC)n0w8st8s

Peer Review for Wonderlic Test

Hello All! I am in need of peer reviewers for the article on the Wonderlic Test. Since the Wonderlic is an intelligence test, this seems a good place to solicit peer reviewers. Any and all help would be much appreciated. Thanks for your time. Mdwilliams2 (talk) 21:52, 29 March 2012 (UTC)

I think that this link should be included into the article please help link it

I think that the jobs section may benifit from a inner-wikipedia link to the Griggs v. Duke Power Co. were the supreme court found that under Title VII of the Civil Rights Act, if such IQ tests disparately impact ethnic minority groups, businesses must demonstrate that such tests are "reasonably related" to the job for which the test is required. Basically you can not use an IQ test to determine job placement. ~Thanks — Preceding unsigned comment added by 76.16.18.252 (talk) 22:08, 10 April 2012 (UTC)

You can use an IQ test in hiring. You just can't use it for jobs for which you can't reasonably argue that a particular level of intelligence is required. That is, you can't use it just to discriminate against groups with statistically lower IQs. 184.78.155.105 (talk) 12:46, 30 April 2012 (UTC)

iq and crime correlation

It is stated in the text that crime rates are lower at very low iqs, peak at moderately low, and then decline at higher iqs. Let's assume this is true. Then a correlation (never stated what type of correlation: pearson? spearman? or other?) shows a relatively low correlation nonetheless. Here's the thing. Most correlation coefficients will only reflect strength of a model if the relationship between two variables is linear and/or monotonically increasing or decreasing. The relationship described would be humped shape, and a correlation measure is not appropriate. A low correlation would be found even if the graph of iq vs. crime rate was perfectly hump shaped with no noise at all in the data. I would look for counter claims to this correlation argument as this is something obvious to anyone with any background at all in data analysis. — Preceding unsigned comment added by 76.92.68.79 (talk) 01:05, 28 April 2012 (UTC)

Renaming Individual differences psychology to Differential psychology

I'd appreciate some contributions to the discussion here.--Victor Chmara (talk) 17:20, 14 June 2012 (UTC)

People with the highest intelligence

Croatian writer Giancarlo Kravar: American Super Scolar portal published a list of 10 most intelligent living people, according to IQ (intelligence coefficient). According to the Croatian daily Jutarnji List, the most popular in the list is a planetary science icon Stephen Hawking (70) with an IQ 160th. Higher IQ, even 230, the list has a mathematician Terence Tao (36) who only 24 years old was a full professor at the University of California at Los Angeles. Followed by physicist Christopher Hirata (30), IQ 225th. Hirata was 16 years old, but worked for NASA. And Korean Kim Ung-Yong as a teenager worked for NASA, and with two years spoke Korean, Japanese, Portuguese, German and English. The list is just one woman, Hungarian Judit Polgar Chess's master (35) with an IQ 170th. She is the only woman who won, 1993., the former world chess champion Garry Kasparov, IQ 190, also on the list, as well as Paul Allein, co-founder of Microsoft, the British mathematician Sir Andrew Wills, who became famous Fermat's last theorem solution, one of the most difficult mathematical problems, and on the list are two people from show business, television producer Rick Rosner and actor James Woods. 78.2.99.46 (talk) 16:30, 30 August 2012 (UTC)

IQ and race

No one has been brave enough to tackle this one.I understand that Stanford University has done considerable work on this area.East Asians(read Chinese) score 3 points higher than Europeans etc I heard a discussion which suggested that Africans have the lowest scores of all.The type of IQ test was not discussed.One university in California uses this information in conjunction with its own testing to select its students.I note that they have a disproportionate number of East Asians on their student roll.Anyone got a reference to back this up?

At the article about Race and IQ there's quite a few references - don't believe everything you read though.·ʍaunus·snunɐw· 02:57, 16 May 2012 (UTC)

Why do they delete my contribution (below) to this article? These are facts that I've found in many articles.

Countries located in the northern region tend to have higher average IQ. IQ seem to increase in northern regions where it is colder. There is a positive correlation between brain size and IQ. Brain size tends to be bigger in colder climates, and it tends to be smaller in hotter climates. For example, northern countries like England, Germany, China, Korea, and Japan have higher average IQ than southern countries like Vietnam, Cambodia, India, Nigeria, and Mexico. This is a visible pattern in the global IQ distribution.

It is correct that this information is frequently repeated, but it is based on controversial studies by controversial scientists and the conclusions should not be presented as fact. Especially not their conclusions regarding the causes of these mesured differences. Please read the articles on Race and Intelligence and Nations and Intelligence. Also this research doesn't necessarily belong in this article. Especially not supported only by news sources - which are not reliable for science topics. Please don't include it again in the same form.·ʍaunus·snunɐw· 10:38, 20 July 2012 (UTC)

Its often frowned upon by modern day scientists (and unfortunatly researched on too much by the wrong people in the 19th-20th century) that we are all adapted to suit out environments, we are not above nature, so maybe higher IQ gives an advantage to survive (coordinating attacks agaisnt mammoths, for example) as much as being able to run fast does (such as being chased by predators). Some people will say it is racist to say that certain races are better at doing certain things, but until I see a white man win the mens 100m final my argument stands! (Fdsdh1 (talk) 17:33, 7 September 2012 (UTC))

Job performance section

Article states; "Some US police departments have set a maximum IQ score for new officers (for example: 125, in New London, CT), under the argument that those with overly-high IQs will become bored and exhibit high turnover in the job. This policy has been challenged as discriminatory, but upheld by at least one US District court. [73]"

I think that it should not say "some" unless there is documented proof that another police department besides the New London, CT police department will reject you for having too high of an IQ. I believe that the article would be much more acurate if it said "ONE" police department and then mentioned New London, CT. KingMouse3645 (talk) 00:17, 23 September 2012 (UTC)

It's being used as an existential quantifier. TippyGoomba (talk) 03:44, 23 September 2012 (UTC)

No total ordering of multi-dimensional talent

Intelligence is a collection of skills - memory, problem solving, creativity, language skill, math skill, etc. Thus it can never be measured solely by one number. And mathematically, it is not possible to define a total ordering of a multi-dimensional talent. DonPMitchell (talk) 23:05, 6 October 2012 (UTC)

All those skills are correlated with each other, with the common variance accounting for about half of all variance in a battery of diverse tests. The predictive validity of IQ batteries is almost entirely due to the common variance, as is their heritability. That's why the composite score is much more important than any of the subtest scores. See here for details.--Victor Chmara (talk) 23:27, 6 October 2012 (UTC)

See also: Why IQ is not a covariate in cognitive studies of neurodevelopmental disorders. — ArtifexMayhem (talk) 09:29, 8 October 2012 (UTC)

Interventions

About the Abecedarian Project. Is it really appropriate to say that it produced lasting gains? On the 3rd page of this PDF you can see a graph of the IQ measurements. At 0.25 months, there is no gap between the intervention and control groups. At 0.5 months there is an increase though of (I think) 4.4 points, and that's where it is at around 5 years. But if you look back at 1.5 years, the gap is 19 points. Doesn't this mean that 4.4 points are in the room for error? It all looks sort of weird, like the 4.4 points might not necessarily mean anything, so what do psychometricians/intelligence researchers say about it? Biggirlnow (talk) —Preceding undated comment added 09:51, 17 October 2012 (UTC)

Indeed, the results of this study have been disputed because the difference between the control and treatment groups was present almost from the outset (although the difference is not necessarily statistically significant at particular ages). A while ago I added some criticisms here. Essentially, the treatment group's mean IQ never improved, while the mean IQ of the control group declined very early in the project and stayed at a relatively low level since. It has been suggested that the randomization was faulty, resulting in mean differences between the two groups that had nothing to do with treatment effects.--Victor Chmara (talk) 10:38, 17 October 2012 (UTC)

Clarification needed?

"Standard intelligence tests, such as the Stanford-Binet, are often inappropriate for children with autism; the alternative of using developmental or adaptive skills measures are relatively poor measures of intelligence in autistic children, and may have resulted in incorrect claims that a majority of children with autism are mentally retarded."

This is not universally true over the whole autism spectrum. As someone with Asperger's syndrome (and an IQ over 120), and as someone who knows several others with Asperger's (one of which I know to have a high IQ as well), I can say with certainty that Asperger's syndrome doesn't fit that claim. I'm guessing there are other forms of high-functioning autism that don't fit it either.

That sentence should be changed for accuracy. 24.245.50.143 (talk) 10:23, 24 February 2013 (UTC)

IQ decreasing?

Does this deserve a mention here (and in Flynn effect)?:

http://www.sciencedirect.com/science/article/pii/S0160289613000470 "Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time"

Comp.arch (talk) 18:11, 23 May 2013 (UTC)

Nah, it's just one study.--Victor Chmara (talk) 21:56, 23 May 2013 (UTC)

Outdated classifications?

Fowler (1965 edition, revised by Gowers), in the entry on I.Q., gives the following gradations:

• 130+ Very superior
• 120–129 Superior
• 110–119 Bright average
• 90–109 Average
• 80–89 Dull average
• 70–79 Borderline
• 50–69 Feeble-minded
• 25–49 Imbecile
• 24- Idiot

I remember seeing these before, with the statement that they were no longer used — presumably because the terms for the lower grades are considered offensive.

Who introduced these terms, and when were they abandoned (if, indeed, they have been)? Should this information go into the article? Paul Magnussen (talk) 20:02, 17 October 2012 (UTC)

The newly revised subarticle IQ classification has full updates on the topic of IQ classification, with citations to historical sources and the latest authoritative handbooks for pyschologists. -- WeijiBaikeBianji (talk, how I edit) 19:02, 19 August 2013 (UTC)

Let's discuss some of the recent edits.

I see there have been recent edits to this article both by I.P. editors and by editors with Wikimedia project usernames. Let's discuss a path forward for further improvements of this article. As I often recommend, I will recommend here that 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, how I edit) 19:04, 19 August 2013 (UTC)

I see you deleted a section saying you had some source to back up something. The usual way of improving Wikipedia is to add to the articles not remove sections with so little justification. Pruning is for when there is duplication or some bits don't satisfy WP:WEIGHT. Just saying you agree with someone else and that you have a source doesn't establish that sourced content has zero weight. Dmcq (talk) 19:21, 19 August 2013 (UTC)

Ancient Chinese testing

There seems to be a rather odd verifiability issue here with regard to the article's claim about IQ testing in ancient China. I don't doubt that the editor who cited the 2004 Sternberg handbook correctly passes on what one article in that handbook says. (That handbook, which I have circulated from a large academic library before, is a source I can check again.) But I very much doubt that the statement is in agreement with better sources on ancient Chinese history, especially the statement about the tangram, as Sinology is the topic of my undergraduate higher education. I'll have to check what better Chinese-language sources say--the off-hand statements I see about Chinese antecedents to Western IQ testing never seem to draw on reliable historical sources. -- WeijiBaikeBianji (talk, how I edit) 23:03, 23 August 2013 (UTC)

Different kinds of intelligences

This article deals only about the mathematical-logical intelligence, but I would argue that there are also other kinds of intelligences. As an example musical intelligence, a person that at once can determine the tone and octave of each note played. There are also verbal intelligence, the ability to discover lies - or make them trustworthy, pursuasive powers and formulating certain speeches. (like "Neve before has so few done so much for so many" by Churchill about the RAF-pilots in 1940. Perhaps Churchill wouldn't have scored very high at a common IQ-test (?) , but he was intelligent in atleast some way) Boeing720 (talk) 17:27, 7 September 2013 (UTC)

I take it you haven't even read the contents list of the article. Dmcq (talk) 18:00, 7 September 2013 (UTC)

Source list of possible use for editing this article

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, how I edit) 15:55, 24 October 2013 (UTC)

Review of article structure

Like most articles on Wikipedia, this article has grown over the years by accretion of material from a large and diverse group of editors, some referring to no source, some referring to one or two sources, and many referring to primary sources (which are not preferred by the Wikipedia reliable sources policy). I'm posting an open invitation here to any editor who so desires to discuss the overall structure and sourcing of this article. I see this article is currently rated B-class, high-importance by WikiProject Psychology, and I see no reason why collaborative effort couldn't bring this article up to featured article status. While digging into sources on this article's topic and subtopics, I did a June 2013 update to IQ classification. In general, I have just about all the sources cited there immediately at hand, and can dig into other sources as needed to start touching up Intelligence quotient. I'd be happy to have all of you join in and comment on the sources and what article structure they suggest here as edits proceed. -- WeijiBaikeBianji (talk, how I edit) 16:06, 24 October 2013 (UTC)

Hampshire et al. study

I removed discussion of this study from the article. The source used, The Daily Mail, cannot be regarded as a reliable source for technical arguments (or anything, really). More importantly, to pay any attention to this one study, whose only conspicuous feature is the authors’ successful publicity campaign for it, is to give undue weight to marginal views. There are far more reputable and mainstream criticisms of g available (e.g., those of Cattell and Horn). The structure of intelligence has been a focus of massive research for more than a century, so there is absolutely no reason to discuss recently published, unsupported (in fact, already falsified, see below) theories in this article.

BTW, the claim that the Hampshire et al. study ”largest ever online study of intelligence” is meaningless puffery, because theirs is a convenience sample and their data are of bad quality. Much larger non-online studies of IQ exist (e.g., Project Talent). Moreover, the brain scan part of the Hampshire study had a sample size of 16 (!), i.e., any competent neuroscientist would be very reluctant to draw strong inferences from it.

If we nevertheless were to discuss the Hampshire study, we should, of course, also discuss criticisms thereof. Michael Ashton and colleagues have have published two articles refuting the claims of Hampshire et al. See [1] and [2]. The first paper shows, using confirmatory factor analysis, that a higher-order g factor model fits the online test data collected by Hampshire et al. better than does the non-g model used in the original study. In other words, the conclusions made by Hampshire et al. on the basis of the ”largest ever online study of intelligence” are firmly refuted when standard psychometric methods are used. The second paper shows that the conclusions Hampshire et al. draw from the brain scan analysis are unsupported by the data. They have no data on individual differences in brain structure in relation to test performance, so they cannot claim that there are no correlated individual differences across different parts of the brain.

We could include the Hampshire et al. study in this article and then also discuss, based on the two articles by Ashton et al., why it’s such a useless and incompetent piece of research, but I don’t think it makes sense to further clutter up this article with such tangential discussions.--Victor Chmara (talk) 17:43, 7 December 2013 (UTC)

If it's been successfully challenged, I agree it doesn't belong in there. But has it? "The comment by Ashton, Lee, and Visser (in press) seeks to find fault in the recent article ‘Fractionating Human Intelligence’ (Hampshire, Highfield, Parkin, & Owen, 2012). However, several of their key points are misleading and, more importantly, they fail completely to acknowledge the main novel contribution of the original article. More specifically, their comment focuses entirely on the behavioural data and makes no attempt to consider the relationship between the neuroimaging and behavioural results (Hampshire et.al, 2012). This is a major oversight, because the main point of the original article was an alternative perspective on the nature of Intelligence that considered how the factors of human ability reflect the manner in which the human brain is organised into specialised functional systems. Moreover, their argument for disregarding the imaging analyses is demonstrably weak. Here, we argue, that data from individual differences analyses and brain imaging analyses are complementary and must be considered together, because, whilst they relate to the same underlying cognitive systems, they have quite different properties. The weaknesses when analysing one set of data are complemented by the strengths when analysing the other. Consequently, by combining the two, it is possible to further constrain our understanding of the architecture of human cognition."[3]

Our opinions of the research are irrelevant. It's clear you think it's rubbish, but hopefully you know our opinions aren't what governs content.

I only kept the Daily Mail in there for the quotes, which I think is ok. I'm not sure how the Science Museum, London blog ref I thought I'd added got lost, and ScienceDaily is certainly an RS, you seem to have missed that. Dougweller (talk) 18:52, 7 December 2013 (UTC)

That paper by Hampshire et al. is a response to the first paper by Ashton & co. Hampshire et al. do not challenge the CFA analysis of Ashton et al., thus tacitly admitting that their online test data do not support their non-g model. In their first paper, Ashton et al. mostly ignored the brain scan part of the original study because of its glaring conceptual and methodological errors. In their second paper, Ashton et al. explain, in very clear terms, why the brain scan analysis does not support the conclusions that Hampshire et al. have made.

But the psychometric incompetence of Hampshire et al. is beside the point. The purpose of Wikipedia articles is to describe the views that are widely present in reliable sources, preferably secondary sources. As a rule, novel arguments and theories that have not received support in secondary sources should not be included. I quote from WP:UNDUE:

Wikipedia should not present a dispute as if a view held by a small minority deserved as much attention overall as the majority view. Views that are held by a tiny minority should not be represented except in articles devoted to those views (such as Flat Earth). To give undue weight to the view of a significant minority, or to include that of a tiny minority, might be misleading as to the shape of the dispute. Wikipedia aims to present competing views in proportion to their representation in reliable sources on the subject.

...

If a viewpoint is in the majority, then it should be easy to substantiate it with reference to commonly accepted reference texts;

If a viewpoint is held by a significant minority, then it should be easy to name prominent adherents;

If a viewpoint is held by an extremely small (or vastly limited) minority, it does not belong in Wikipedia regardless of whether it is true or not and regardless of whether you can prove it or not, except perhaps in some ancillary article.

...

Keep in mind that, in determining proper weight, we consider a viewpoint's prevalence in reliable sources, not its prevalence among Wikipedia editors or the general public.

...

If you can prove a theory that few or none currently believe, Wikipedia is not the place to present such a proof.

The arguments of Hampshire et al. can be regarded as those of a tiny minority. They have no currency in the mainstream literature on intelligence. To the extent they have received any attention from experts in differential psychology, it has been entirely negative (the Ashton et al. papers). The consensus model in intelligence research is that IQ differences are explained by a hierarchy topped by the g factor. This consensus has resulted from the consistent results of hundreds of different studies, as described in review articles[4]. Similarly, the neurobiology of intelligence has been subject to lots of research, the results of which are summarized in review articles[5]; the idea that one study with N=16 should be regarded as a major point of reference is ridiculous. Reviews articles and the like should be the major sources for articles like this.

Thus, discussing the claims of Hampshire et al. is not justified in light of Wikipedia's policies.--Victor Chmara (talk) 20:13, 7 December 2013 (UTC)

Doug, I appreciate that you are just checking on whether the article currently gives due weight to dependable scholarship on IQ (it largely doesn't, because it is sourced too much to primary sources), so, agreeing with Victor and with Aprock here, I will dig up a list of sources previously agreed on by several editors working on a related subarticle. I'll post that here as a new talk page section, inviting comment by other editors. -- WeijiBaikeBianji (talk, how I edit) 01:24, 8 December 2013 (UTC)

Press releases are almost certainly not a good barometer of due weight. Similarly, recent research which hasn't been validated, or percolated through to tertiary sources is difficult to handle, again because due weight is likely to be confused with recentism. aprock (talk) 20:16, 7 December 2013 (UTC)

91.145.135.101 undid my revision on adding survey data about expert opinion of causes of race differences

But he gave no reason for doing so, and my revision added referenced, relevant material that are widely known in the field. I know because I'm a researcher in this field. Presumably, this user has some complaint about this revision, so I'm opening up the discussion here so that he can explain himself. In the meanwhile, I have reversed his decision. Deleet (talk) 00:48, 13 January 2014 (UTC)

That survey is not a good source for establishing facts of the world. (It is not a current source either on opinions of psychologists, and in fact there is another psychologist just now who is trying to bring the survey up to date.) I'll check what the article text says just now. -- WeijiBaikeBianji (talk, how I edit) 02:55, 13 January 2014 (UTC)

Having looked at the article, I now see what the problem was. That's not a correct use of the survey as a source. I have read the entire Snyderman and Rothman article, and moreover read articles about the origin and editing of their article and their later book a few years ago while working on other parts of Wikipedia. Today's reliable secondary sources do not report the same view among psychologists. (Yes, I struck out that part of the article text, with what I hope was a more informative edit summary.) Thanks for checking. Let's discuss more up-to-date reliable secondary sources. -- WeijiBaikeBianji (talk, how I edit) 02:59, 13 January 2014 (UTC)

What are those "today's reliable secondary sources" that contradict Snyderman & Rothman? I don't think there are any. The only comparable study is that by Rindermann et al., whose results were recently presented at the ISIR conference. The results show that the hereditarian view on the black-white gap is the predominant one among psychometricians. A shortcoming of this study is that its sample size is much smaller than that of the S & R study. Nor has the new study been properly published yet.--Victor Chmara (talk) 11:12, 13 January 2014 (UTC)

• Snyderman and Rothman has only historical value. The APA paper by Nisbett Flynn et al. Is a very strong indication that this is not the dominant view within the field. As are the recent books by Mackintosh and Hunt. Including the Snyderman and Rothman study is extreme undue weight and misrepresents the field in a strongly POV way. The Section here should reflect and summarize the article on R & I - which does not give this much weight to Snyderman/Rothman and which does not suggest that the hereditarian view is dominant.User:Maunus ·ʍaunus·snunɐw· 23:33, 13 January 2014 (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[6] 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) 21:01, 5 December 2013 (UTC)

Yes, but what does this have to do with the talk page? Deleet (talk) 00:42, 13 January 2014 (UTC)

The review articles published by the new journal will be very helpful for updating this Wikipedia article and many other Wikipedia article, as they meet the highest standard of reliable sources for Wikipedia article text. The Journal of Intelligence — Open Access Journal website has just been updated with the new articles for the latest edition of the journal, by eminent scholars on human intelligence. -- WeijiBaikeBianji (talk, how I edit) 21:29, 16 February 2014 (UTC)

Misinterpretation of Confidence Intervals in the Article

There is a pretty significant error in reasoning about statistics in the article.

Another description is there is a 95% chance the true IQ is in range from four to five points above to four to five points below the test IQ, depending on the test in question.

This is a common misinterpretation of confidence intervals, but one that is usually covered in a first class on statistics. Null hypothesis testing and confidence intervals do not tell you the probability that any hypothesis is true. Nor do they tell you that any measurable quantity is in some interval with some probability. A correct interpretation is that if you conducted a 1000 (or some other large number approximating infinity) IQ tests with the same error bounds, then approximately 95% of the intervals would contain the true mean. I am going to delete this sentence and a few other statistical errors.50.181.78.116 (talk) 09:19, 2 May 2014 (UTC)

Calculation

How do you calculate IQ? Please explain in the article. Qwertyxp2000 (talk) 06:26, 28 June 2014 (UTC)

I'll check what the article currently says as I update the article. I was just transcribing new reliable source quotations yesterday. -- WeijiBaikeBianji (talk, how I edit) 14:14, 7 July 2014 (UTC)

I am wondering the same. 95% of what population? Or is it 95% of world population due definition. What is the upper IQ scores, by definition on a 7 billion population? Etc? --Stalkerkun (talk) 16:41, 25 July 2014 (UTC)

IQ tests are normed by their publishers for national populations. You shouldn't assume any validity for an IQ test given in a country that wasn't included in the publisher's norming studies. -- WeijiBaikeBianji (talk, how I edit) 22:54, 25 July 2014 (UTC)

Quotation

I deleted the quoted words "demolish some long-cherished beliefs, and raise a number of other interesting issues along the way" because they are pointless. The reader doesn't know either what beliefs were demolished or what issues were raised. So what does the reader get out of this quotation? Srnec (talk) 19:29, 31 August 2014 (UTC)

I see you are new to editing this article, and (based on your contribution history) new to this topic. Don't worry about it. Already the quotation stands as an eminent expert's opinion on the phenomenon of the Flynn effect and how it relates to human intelligence research, and since there is no deadline, you don't have to worry about readers more knowledgeable about the research on the topic may be able to get out of that sourced statement already, nor about what editors who frequent this article plan to do with the quotation to improve the article all the way up to good article status and then featured article status. In my humble opinion as an editor who has had this article on my watchlist for years and has contributed many sources to this article, it's better for the article for the quotation to stand in article text pending future editing. -- WeijiBaikeBianji (talk, how I edit) 19:37, 31 August 2014 (UTC)

I tend to agree with Srnec that that particular quote adds no information to the article and ought to be removed.User:Maunus ·ʍaunus·snunɐw· 19:40, 31 August 2014 (UTC)

Are you willing to wait for an article expansion to make the connection to why the quotation sums up the article section? -- WeijiBaikeBianji (talk, how I edit) 22:59, 31 August 2014 (UTC)

In any event, it would be helpful to look up the actual book to see how the author connects Flynn's observation of secular increases in IQ test raw scores to other issues in the theory of IQ testing. -- WeijiBaikeBianji (talk, how I edit) 23:01, 31 August 2014 (UTC)

Added progresive difficulty in high school table under scholastic.

Note, the individual could very well be the complete lazy type with IQ in the 160´s, which is not measurable within what are scholastic high school efforts.

Someone else can jot down the differences between male and female performance, where the gals have a lower SD differencial norm between them. IE, a woman with a boys IQ of 130, does NOT have a girls IQ of 130 but a girls IQ of 145, when the SD differencial is 10 points instead of the normalized 15 points, which makes it important to differenciate the two aspects accordingly. — Preceding unsigned comment added by 201.208.189.225 (talk) 20:45, 1 September 2014 (UTC)

You have spent no time researching this topic, and are entirely unfamiliar with this very mature study that has over a century of proven results. You have no understanding of what "g" represents, or even the IQ metric itself. — Preceding unsigned comment added by Polemicist2 (talk • contribs) 19:58, 4 September 2014 (UTC)

Does this come from a reliable source? (I don't see any source cited by the inserted content, and this is not a mainstream concern of the professional publications already cited in the article.) Without a source, this doesn't belong in a Wikipedia article. -- WeijiBaikeBianji (talk, how I edit) 23:35, 1 September 2014 (UTC)

Well in theory it is possible that someone is just lazy but still is very intelligence.. Those exemptions exits.. But how does that change that high IQ people get the best grades in class.. There is a correlation between IQ and grades 0.5.. The lazy ones is the reason the correlation is only 0.5 is guess... But yeah laziness does play into how you do in life...MicroMacroMania (talk) 17:35, 7 September 2014 (UTC)

If IQ tests test a particular form of cognitive ability that is also favored in western education the correlation becomes obvious. Especially if we assume that it it a cognitive ability that improves with practice as has been shown to be the case in several studies, where test performance was directly related to the degree of prior experience with performing similar cognitive tasks. User:Maunus ·ʍaunus·snunɐw· 19:40, 7 September 2014 (UTC)

Interesting study - IQ genetic evidence on the way maybe

http://www.pnas.org/content/early/2014/09/05/1404623111.full.pdf — Preceding unsigned comment added by MicroMacroMania (talk • contribs) 09:59, 9 September 2014 (UTC)

Offhand I can think of a number of problems with that paper where the gene may be associated with upbringing e.g. if they are Indians or Hispanics. I'd wait for a bit of discussion on it and see how well it gets through. Heritability of IQ would probably be the eventual article and some of the genes might make it to list of human genes. Dmcq (talk) 13:36, 9 September 2014 (UTC)

This article talk page is about editing the article, and since Wikipedia content guidelines on reliable sources strongly favor secondary sources over primary sources, it may be quite a while before this new primary research publication has any role as a source in any Wikipedia article. (It would appear, if at all, only as "[citation to secondary source (citing primary source)]".) Right now, the big thing that this article Intelligence quotient most needs is a big reduction in the number of unreplicated primary sources cited, along with a corresponding increase in the number of citations to reliable secondary sources (which are already mentioned here on the article talk page). -- WeijiBaikeBianji (talk, how I edit) 15:42, 9 September 2014 (UTC)

Thanks for the recent edits

I see two other editors in the last twenty-four hours have been digging into an important mainstream secondary source to update this article regarding IQ as a predictor of work performance. I had in mind to do the same (I have the source at hand), so I thank you for sparing me that task. I more generally have had in mind for a long time to extensively update this article to trim away citations to primary sources, to add in citations to reliable secondary sources, to rearrange sections and subsections to reduce redundancy and match the flow of topics and subtopics in most other reliable sources on this article's broad topic, and generally to do a coherent rewriting of the article from top to bottom. Having each of the editors who have just been involved in editing the article involved in that task will be a delight. Of course I welcome anyone else looking on who has access to good sources or who would like to read this article with fresh eyes to see if it is coherent and backs up its statements with citations to join in on the work. This article is on a topic important enough that the article deserves a chance to be brought up to good article and then featured article status, and I think the recently involved editors will be good collaborators in an ongoing effort to do that. See you in the article text; I'll be keeping off-line drafts of different states of editing as we go along, especially to make sure that all sources are verified. -- WeijiBaikeBianji (talk, how I edit) 13:35, 9 October 2014 (UTC)

Reverts of data table edits

One new user appears to be edit-warring in editing the content of the sortable data table in the article, despite being reverted by at least four other editors. I have the source at hand for the data table, and I confirm that the text that the other editors are restoring is correctly sourced. -- WeijiBaikeBianji (talk, how I edit) 20:44, 6 November 2014 (UTC)

I checked the source once more today just to be sure. It appears that a follow-up vandal with a new user account is coming to replace the user who was just banned for edit-warring. -- WeijiBaikeBianji (talk, how I edit) 22:38, 6 November 2014 (UTC)

Future direction of the article

We might want to add unemployment or welfare etc.ParanoidLemmings (talk) 22:39, 6 December 2014 (UTC)

The section is very poorly sourced now, and even the content with references doesn't fairly represent what the references actually say. The whole section will have to be rewritten. I have been gathering sources for that. -- WeijiBaikeBianji (talk, how I edit) 02:52, 7 December 2014 (UTC)

I can agree with that, Some informations don't even have a source.ParanoidLemmings (talk) 09:21, 8 December 2014 (UTC)

We might want to change the part about brain size to something with sources. We also need a part about mental chronometry and its correlation with IQ. And what about testorone, that have some correlation with IQ. I will look into it. Furthermore the passage about sex differences in IQ seems biased, that view is not universally accepted. James Flynn and Nisbett disagree with that view from what I understand.ParanoidLemmings (talk) 11:33, 9 December 2014 (UTC)

"Those other forms of behavioral observation are still important for validating classifications based primarily on IQ test scores."

Read this sentence. It's contradictory. How can they be important if they're based PRIMARILY on IQ tests scores? I don't participate in Wikipedia but this example goes to show how many of you need to find something else to do than write glib and contradictory sentences — Preceding unsigned comment added by 71.60.215.192 (talk) 19:59, 28 March 2015 (UTC)

Useful sources for updating this and related articles

I see that there is a discussion among editors about correct sourcing of this article. As discussed in the last few months through an RFC on the Race and intelligence article talk page (the talk page of a subarticle of this article), there are a number of current sources available to editors that meet the Wikipedia guidelines for reliable sources in medicine, which is generally the correct source guideline to apply to articles on human intelligence and IQ testing. (That's because IQ tests are literally used in medical diagnosis, and also used in high-stakes forensic contexts such as finding diminished criminal responsibility in criminal trials, and consequential decisions such as school placement for children.) I will mention sources previously agreed to in a nonexhaustive list of good sources for the other article that also fit this article here, along with a few other sources that come just with my personal recommendation until other editors comment here (as I encourage all of you to do).

As an update, I'll mention that I've also taken care on repeated visits to my friendly state flagship university library to use online journal access to basically exhaustively check all the references currently cited in this and related articles. With all those journal articles downloaded, and with the sources mentioned here, I hope to plunge into top-to-bottom updates of this article (probably starting out as section fixes a few sections at a time, after testing in a user sandbox) Real Soon Now. Of course all of you watching this page are very welcome to comment on improvements for this article. Besides the sources listed here and the sources already referenced in the article, in principle most all of the newer and more scholarly sources in my continually updated user bibliography on human intelligence may be applied to updating this article. Your suggestions of more reliable sources, and especially sources that meet the guideline for reliable sources for medicine are warmly encouraged. -- WeijiBaikeBianji (talk, how I edit) 21:52, 27 March 2014 (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) 16:39, 20 April 2014 (UTC)

Sources recommended in the previous RFC useful here too

• Sternberg, Robert J.; Kaufman, Scott Barry, eds. (2011). The Cambridge Handbook of Intelligence. Cambridge: Cambridge University Press. ISBN 9780521739115. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This authoritative handbook appears to be cited only as a further reading reference, for one specific chapter in this handbook, in the current version of this Wikipedia article. It deserves dozens of citations in this article. It includes chapters by N. J. Mackintosh, Susana Urbina, John O. Willis, Ron Dumont, Alan S. Kaufman, Janet E. Davidson, Iris A. Kemp, Samuel D. Mandelman, Elena L. Grigorenko, Raymond S. Nickerson, Joseph F. Fagan, L. Todd Rose, Kurt Fischer, Christopher Hertzog, Robert M. Hodapp, Megan M. Griffin, Meghan M. Burke, Marisa H. Fisher, David Henry Feldman, Martha J. Morelock, Sally M. Reis, Joseph S. Renzulli, Diane F. Halpern, Anna S. Beninger, Carli A. Straight, Lisa A. Suzuki, Ellen L. Short, Christina S. Lee, Christine E. Daley, Anthony J. Onwuegbuzie, Thomas R. Zentall, Liane Gabora, Anne Russon, Richard J. Haier, Ted Nettelbeck, Andrew R. A. Conway, Sarah Getz, Brooke Macnamara, Pascale M. J. Engel de Abreu, David F. Lohman, Joni M. Lakin, Keith E. Stanovich, Richard F. West, Maggie E. Toplak, Scott Barry Kaufman, Ashok K. Goel, Jim Davies, Katie Davis, Joanna Christodoulou, Scott Seider, Howard Gardner, Robert J. Sternberg, John D. Mayer, Peter Salovey, David Caruso, Lillia Cherkasskiy, Richard K. Wagner, John F. Kihlstrom, Nancy Cantor, Soon Ang, Linn Van Dyne, Mei Ling Tan, Glenn Geher, Weihua Niu, Jillian Brass, James R. Flynn, Susan M. Barnett, Heiner Rindermann, Wendy M. Williams, Stephen J. Ceci, Ian J. Deary, G. David Batty, Colin DeYoung, Richard E. Mayer, Priyanka B. Carr, Carol S. Dweck, James C. Kaufman, Jonathan A. Plucker, Ursula M. Staudinger, Judith Glück, Phillip L. Ackerman, and Earl Hunt.)

• Weiss, Lawrence G.; Saklofske, Donald H.; Coalson, Diane; Raiford, Susan, eds. (2010). WAIS-IV Clinical Use and Interpretation: Scientist-Practitioner Perspectives. Practical Resources for the Mental Health Professional. Alan S. Kaufman (Foreword). Amsterdam: Academic Press. ISBN 978-0-12-375035-8. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |displayeditors= ignored (|display-editors= suggested) (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (The several individual chapters in this book should be cited much more often in this article. This book includes chapters by Diane L. Coalson, Susan Engi Raiford, Donald H. Saklofske, Lawrence G. Weiss, Hsinyi Chen, Jossette G. Harris, James A. Holdnack, Xiaobin Zhou, Jianjun Zhu, Jacques Gregoire, Munro Cullum, Glenn Larrabee, Gerald Goldstein, Timothy A. Salthouse, and Lisa W. Drozdick. I will look for the specific page reference for the sole citation to the article that appears now. )

• Nisbett, Richard E.; Aronson, Joshua; Blair, Clancy; Dickens, William; Flynn, James; Halpern, Diane F.; Turkheimer, Eric (2012). "Intelligence: new findings and theoretical developments" (PDF). American Psychologist. 67 (2): 130–159. doi:10.1037/a0026699. ISSN 0003-066X. PMID 22233090. Retrieved 22 July 2013. {{cite journal}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This major review article in a flagship publication by the American Psychological Association deserves a lot more citations than the one it now has in this article.)

• Mackintosh, N. J. (2011). IQ and Human Intelligence (second ed.). Oxford: Oxford University Press. ISBN 978-0-19-958559-5. {{cite book}}: Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (The first edition of this book is cited, twice, in this article. The article should be updated with many more citations to this edition.)

• Hunt, Earl (2011). Human Intelligence. Cambridge: Cambridge University Press. ISBN 978-0-521-70781-7. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This appears not to be cited at all in the current version of this article, which is a serious omission. I have owned this book since soon after when it was published.)

Other useful sources for this article of WP:MEDRS quality

• Flanagan, Dawn P.; Harrison, Patti L., eds. (2012). Contemporary Intellectual Assessment: Theories, tests, and issues (Third ed.). New York (NY): Guilford Press. ISBN 978-1-60918-995-2. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This comprehensive handbook by multiple authoritative authors is currently mentioned only in the further reading section of this article, which is too little use of this high-quality source. It includes chapters by John D. Wasserman, Randy W. Kamphaus, Anne Pierce Winsor, Ellen W. Rowe, Sangwon Kim, John L. Horn, Nayena Blankson, W. Joel Schneider, Kevin S. McGrew, Jie-Qi Chen, Howard Gardner, Robert J. Sternberg, Jack A. Naglieri, J. P. Das, Sam Goldstein, Lisa Whipple Drozdick, Dustin Wahlstrom, Jianjun Zhu, Lawrence G. Weiss, Dustin Wahlstrom, Kristina C. Breaux, Jianjun Zhu, Lawrence G. Weiss, Gale H. Roid, Mark Pomplun, Jennie Kaufman Singer, Elizabeth O. Lichtenberger, James C. Kaufman, Alan S. Kaufman, Nadeen L. Kaufman, Fredrick A. Schrank, Barbara J. Wendling, Colin D. Elliott, R. Steve McCallum, Bruce A. Bracken, Jack A. Naglieri, Tulio M. Otero, Cecil R. Reynolds, Randy W. Kamphaus, Tara C. Raines, Robb N. Matthews, Cynthia A. Riccio, John L. Davis, Jack A. Naglieri, Tulio M. Otero, Dawn P. Flanagan, Vincent C. Alfonso, Samuel O. Ortiz, Catherine A. Fiorello, James B. Hale, Kirby L. Wycoff, Randy G. Floyd and John H. Kranzler, Samuel O. Ortiz, Salvador Hector Ochoa, Agnieszka M. Dynda, Nancy Mather, Barbara J. Wendling, Laurie Ford, Michelle L. Kozey, Juliana Negreiros, David E. McIntosh, Felicia A. Dixon, Eric E. Pierson, Vincent C. Alfonso, Jennifer T. Mascolo, Marlene Sotelo-Dynega, Laura Grofer Klinger, Sarah E. O’Kelly, Joanna L. Mussey, Sam Goldstein, Melissa DeVries, James B. Hale, Megan Yim, Andrea N. Schneider, Gabrielle Wilcox, Julie N. Henzel, Shauna G. Dixon, Scott L. Decker, Julia A. Englund, Alycia M. Roberts, Kathleen Armstrong, Jason Hangauer, Joshua Nadeau, Jeffery P. Braden, Bradley C. Niebling, Timothy Z. Keith, Matthew R. Reynolds, Daniel C. Miller, Denise E. Maricle, Denise E. Maricle, Erin Avirett, Rachel Brown-Chidsey, Kristina J. Andren, George McCloskey, James Whitaker, Ryan Murphy, Jane Rogers, and John B. Carroll.)

• Kaufman, Alan S.; Lichtenberger, Elizabeth (2006). Assessing Adolescent and Adult Intelligence (3rd ed.). Hoboken (NJ): Wiley. ISBN 978-0-471-73553-3. {{cite book}}: Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This very useful source is cited in the current version of this Wikipedia article, although some of the material cited is used out of context in the article at present. There are many other references from this handbook that would be good for adding to this article.)

• Kaufman, Alan S. (2009). IQ Testing 101. New York: Springer Publishing. pp. 151–153. ISBN 978-0-8261-0629-2. {{cite book}}: Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This popular book by an experienced author is already cited in the article, and more citations are warranted.)

• Flynn, James R. (2012). Are We Getting Smarter? Rising IQ in the Twenty-First Century. Cambridge: Cambridge University Press. ISBN 978-1-107-60917-4. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This new book by an experienced researcher, published by a university press, deserves much more use than its current mere mention as a further reading source.)

• Slater, Alan M.; Quinn, Paul C., eds. (2012). Developmental Psychology: Revisiting the Classic Studies. Psychology: Revisiting the Classic Studies. Thousand Oaks (CA): SAGE. ISBN 978-0-85702-757-3. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This textbook includes an excellent review chapter on human intelligence issues by Wendy Johnson. Chapters on other issues are by Roger Kobak, Thomas H. Ollendick, Thomas M. Sherman, Peter Muris, Neville J. King, Karen E. Adolph, Kari S. Kretch, David Klahr, Alan M. Slater, Denis Mareschal, Jordy Kaufman, Kelly McWilliams, Daniel Bederian-Gardner, Sue D. Hobbs, Sarah Bakanosky, Gail S. Goodman, Usha Goswami, Coralie Chevallier, Gail D. Heyman, Kang Lee, Jennifer E. Lansford, Richard N. Aslin, and Ann S. Masten.)

• Gregory, Robert J. (2011). Psychological Testing: History, Principles, and Applications (Sixth ed.). Boston: Allyn & Bacon. ISBN 978-0-205-78214-7. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) (This book includes a solid general overview of principles of psychological testing, including IQ testing. It is completely neglected in the current version of this article.)

• Weiner, Irving B.; Graham, John R.; Naglieri, Jack A., eds. (2 October 2012). Handbook of Psychology. Vol. Volume 10: Assessment Psychology. John Wiley & Sons. ISBN 978-0-470-89127-8. Retrieved 25 November 2013. {{cite book}}: |volume= has extra text (help); Cite has empty unknown parameters: |laysummary= and |laydate= (help); Invalid |ref=harv (help) (This source, the second edition of the key volume of a massive, authoritative handbook of psychology, is so recently published that no editor had seen it as of the last time sources were discussed in the RFC at the other article. It is very good, and I now have it at hand in my office. It includes chapters by Irving B. Weiner, John R. Graham, Jack A. Naglieri, Paul M. Spengler, John D. Wasserman, Bruce A. Bracken, Cecil R. Reynolds, Lisa A. Suzuki, Kurt F. Geisinger, Carina McCormick, Mark E. Maruish, James N. Butcher, Celiane Rey-Casserly, Gerald P. Koocher, Leonard Handler, Justin D. Smith, Martin Sellbom, Brandee E. Marion, R. Michael Bagby, Nancy Howells Wrobel, David Lachar, Jeffery P. Braden, Jerry J. Sweet, Steven M. Tovian, Leslie M. Guidotti Breting, Yana Suchy, Richard J. Klimoski, Torrey R. Wilkinson, James R. P. Ogloff, Kevin S. Douglas, Edwin I. Megargee, Barry A. Edelstein, Ronald R. Martin, Lindsay A. Gerolimatos, Tulio M. Otero, Kenneth Podell, Philip DeFina, Elkhonon Goldberg, Rodney L. Lowman, Andrew D. Carson, Robert J. Craig, William H. O’Brien, Kathleen M. Young, Donald J. Viglione, Bridget Rivera, and Yossef S. Ben-Porath. It should be used throughout this article and related articles.)

There is more where these come from, but these are all very high-quality sources that would do much to improve the quality of this article. -- WeijiBaikeBianji (talk, how I edit) 02:56, 8 December 2013 (UTC)

Brilliant stuff. I'll leave it though to those with more interest in the article, I'll bow out now that I've been thoroughly shown the error of my ways. Dougweller (talk) 14:44, 8 December 2013 (UTC)

I'll draw other editors' attention to a source Victor mentioned in the discussion above, which I can acclaim (sight unseen, because I know the journal series and I know other works by the author) as a medically reliable source for further updates of this article. Thank you to Victor for first citing it here. I'll be able to obtain full text of the source he kindly recommended tomorrow. Here is the citation:

*Deary, Ian J. (2012). "Intelligence". Annual Review of Psychology. 63 (1): 453–482. doi:10.1146/annurev-psych-120710-100353. ISBN 978-0-8243-0263-4. ISSN 0066-4308. Retrieved 8 December 2013. {{cite journal}}: Invalid |ref=harv (help)

There are quite a few good sources on the topic of this article that are recent, comprehensively review the earlier literature (both primary research articles and previous secondary sources), and meet the standards of the WP:MEDRS guidelines. I would be delighted to hear suggestions of other sources. -- WeijiBaikeBianji (talk, how I edit) 16:40, 8 December 2013 (UTC)

While looking up something else, I found a good recent article by Tom Bouchard (listed in the journal that published it as an "original research" article, but more of the nature of a review article) that I will consult as I begin article updates in the mainspace article text. There are a lot of good, recent, reliable, secondary reviews of the topic of this article. -- WeijiBaikeBianji (talk, how I edit) 14:17, 7 July 2014 (UTC)

As Aprock and Victor have recently been updating the article after checking sources, I have just saved on off-line copy of the current article text, and I will be scanning that for how sources are used throughout the article. My goal is to find secondary sources, such as those mentioned in this talk page section and others like them, for all the factual topics in the article. As I encounter citations to primary sources in the article test, of which there are now many, I will check the secondary sources to see how they apply and evaluate the primary research literature as they give overviews of this article's topic and its subtopics. That's the editing procedure recommended by WP:RS. As a first step, I will be updating the Bibliography section as I began to do earlier this year with full, templated citations to secondary sources and to the most major and often cited primary sources that are discussed in the professional literature. The preliminary and minor primary sources (unreplicated case reports and the like) can eventually drop out of the inline references in the article as all references are updated to point to current secondary sources. That will be a long slow process--this is just to let everyone know what I intend to do hand-in-hand with other editors working on this article at the same time. -- WeijiBaikeBianji (talk, how I edit) 17:09, 9 October 2014 (UTC)

I thought I should let other editors know that I've been slogging through this article line-by-line in an off-wiki draft to exhaustively verify every reference in the article. Along the way, I discovered a hyperlinked bibliography for Mackintosh's 2011 textbook IQ and Human Intelligence that provides many helpful DOI or PubMed links to articles that are cited in this article or in the better secondary sources about the same topic. I am referring to those articles as I continue editing. -- WeijiBaikeBianji (talk, how I edit) 15:10, 1 December 2014 (UTC)

I see that after all these years this high-page-view article has never made it to good article status, and I think it's time to change that. Especially, noticing that now IQ classification gains more weekly page views than this article, it seems to me that the best way to bring the topic of this article the prominence it deserves on Wikipedia is to rewrite from top to bottom with better sources, until it is ready for a good article nomination. I know there are several conscientious editors who have contributed to this article in the past who are still active on Wikipedia, and I look forward to them joining in on this effort. With that in mind, I'm here to suggest yet another very helpful source. I have full access through my friendly local academic library to Geisinger, Kurt F., ed. (2013). APA Handbook of Testing and Assessment in Psychology. APA Handbooks in Psychology. American Psychological Association. ISBN 978-1-4338-1227-9. Retrieved 15 December 2014. {{cite book}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) This three-volume handbook for practitioners is especially authoritative and comprehensive. Volume 1: Test Theory and Testing and Assessment in Industrial and Organizational Psychology includes chapters by Anita M. Hubley, Bruno D. Zumbo, Kurt F. Geisinger, Edward W. Wiley, Noreen M. Webb, Richard J. Shavelson, Stephen G. Sireci, Tia Sukin, Li Cai, Steven P. Reise, Tyler M. Moore, Mark G. Havil, Randall D. Penfield, Jeanne A. Teresi, Richard N. Jones, Neal M. Kingston, Sylvia T. Scheuring, Laura B. Kramer, David J. Weiss, Michael J. Kolen, Amy B. Hendrickson, John J. McArdle, John J. Prindle, Daniel R. Eignor, Jane Close Conoley, Collie W. Conoley, Rafael Julio Corvera Hernandez, Frederick T. L. Leong, Yong Sue Park, Mark M. Leach, Cathy Wendler, Jeremy Burrus, Michael J. Zieky, Michael C. Rodriguez, Thomas M. Haladyna, Samuel E. Krug, Suzanne Lane, Tim McNamara, John P. Campbell, Juan I. Sanchez, Edward L. Levine, Nathan R. Kuncel, Adam S. Beatty, Neal Schmitt, Juliya Golubovich, Nancy T. Tippins, Robert L. Dipboye, Stefanie K. Johnson, Leaetta M. Hough, Brian S. Connelly, George C. Thornton III, Uma Kedharnath, Robert E. Ployhart, Anna-Katherine Ward, Scott Highhouse, John A. Kostek, Eugene Burke, Carly Vaughan, Ray Glennon, Kevin R. Murphy, Paige J. Deckert, Paul M. Connolly, Deniz S. Ones, Stephan Dilchert, Ann Marie Ryan, Paul R. Sackett, Reeshad S. Dalal, Marcus Credé, Paul J. Hanges, Elizabeth D. Salmon, Juliet R. Aiken. Volume 2: Testing and Assessment in Clinical and Counseling Psychology includes chapters by Janet F. Carlson, Sara Maltzman, Virginia Smith Harvey, William M. Grove, Scott I. Vrieze, Beth E. Haverkamp, Elizabeth V. Swenson, Katie L. Sharp, Alexander J. Williams, Kathleen T. Rhyner, Stephen S. Ilardi, Phillip L. Ackerman, Antonio E. Puente, Antonio N. Puente, Irving B. Weiner, James N. Butcher, Shawn Bubany, Shawn N. Mason, Lisa A. Suzuki, Mineko Anne Onoue, Jill S. Hill, Michael J. Lambert, David A. Vermeersch, Sandra L. Horn, Joni L. Mihura, Gregory J. Meyer, Christopher T. Barry, Paul J. Frick, Randy W. Kamphaus, Kirk Heilbrun, Stephanie Brooks Holliday, Elizabeth M. Altmaier, Benjamin A. Tallman, Mark E. Maruish, Bryan J. Dik, Patrick J. Rottinghaus, Jane L. Swanson, Melanie E. Leuty, Nancy E. Betz, Moin Syed, Margit I. Berman, Sueyoung L. Song, Hyung Chol Yoo, Stephanie T. Pituc, Stephen E. Finn, Hale Martin, Bonnie Moradi, Mike C. Parent, Michael F. Steger, Jennifer E. Stevenson, Kathleen B. Kortte, Cynthia F. Salorio, Daniel E. Rohe, Jo-Ida C. Hansen, Todd J. Wilkinson, Tammi Vacha-Haase, Cindy I. Carlson, Lauren S. Krumholz, Douglas K. Snyder, and H. Elizabeth King. Volume 3: Testing and Assessment in School Psychology and Education includes chapters by Jack A. Naglieri, Janet E. Panter, Bruce A. Bracken, John O. Willis, Ron Dumont, Alan S. Kaufman, R. Steve McCallum, Nancy Mather, Bashir Abu-Hamour, Bridget V. Dever, Randy W. Kamphaus, Carol Robinson-Zañartu, Jerry Carlson, Tanya L. Eckert, Adrea J. Truckenmiller, Jennifer L. Rymanowski, Jennifer L. Koehler, Elizabeth A. Koenig, Bridget O. Hier, Thomas Oakland, Matthew Daley, Giselle B. Esquivel, Maria Acevedo, Thomas Oakland, Solange Muglia Wechsler, Kobus Maree, Matthew K. Burns, David C. Parker, Susan Jacob, Steven E. Stemler, Robert J. Sternberg, Wayne Camara, Sheryl Packman, Andrew Wiley, Diane F. Halpern, Heather A. Butler, Carina McCormick, Jamal Abedi, Rebecca Kopriva, Craig A. Albers, Mark R. Raymond, Richard M. Luecht, Drew H. Gitomer, Courtney A. Bell, Ruth A. Childs, Pei-Ying Lin, Richard J. Tannenbaum, Irvin R. Katz, Ronald K. Hambleton, April L. Zenisky, Neil J. Dorans, Michael E. Walker, Christopher P. Borreca, Gail M. Cheramie, Elizabeth A. Borreca, Kadriye Ercikan, Juliette Lyons-Thomas, Gregory Camilli, Derek C. Briggs, Finbarr C. Sloane, Ting-Wei Chiu, John Hattie, and Heidi Leeson. This source will be very useful for updating this article. See you on the wiki. -- WeijiBaikeBianji (talk, how I edit) 18:43, 6 April 2015 (UTC)

High-importance, B-class Article

This article has been rated high-importance for WikiProject Psychology, but its content rating is a (generous) B class. This article gets lots of page views, so I propose that we collaborate to improve Intelligence quotient to good article status by reading reliable sources carefully and discussing aspects of this article to improve. I have seen this process work very well over the last few months on the English language article, which should be submitted for good article review soon. Who would like to do this? What sources do you know about that would be good for updating and fact-checking this article? -- WeijiBaikeBianji (talk, how I edit) 20:01, 6 April 2015 (UTC)

Removal of "brain anatomy" section

[7] What is the basis for removing the article's discussion of brain anatomy? This section was cited to a high-quality source, and it seems strange for the Wikipedia article to make no mention of the neurological basis for human intelligence. 107.6.121.157 (talk) 14:26, 7 April 2015 (UTC)

This introduces the issue of the scope of this article, which other editors have desired to discuss. Thanks for bringing this discussion to the article talk page. Other editors have been wondering about the topic scope of this article. In view of the presence of other articles on Wikipedia on closely related topics, and in view of which redirect terms lead to this article (examples are "IQ test", "Intelligence test", "Intelligence testing", and so on), I think it's fair to say that there is a distinction between the core topic of this article and the topic of, say, the more newly created article Human intelligence. I fully agree that the source cited in that small section of this article is a good source and well suited for use on Wikipedia. (The source's co-authors have written newer and more on-point articles suitable for various articles on Wikipedia since then, too.) My concern as I take a look at this article from top to bottom is that its topic focus be tightened to tests and procedures for assessing human intelligence as such, with more of the content related to the nature of human intelligence and the correlates of human intelligence moving over to (or being newly written for) the articles that are focused more squarely on those topics, for example Human intelligence. The comment by the I.P. editor here is thoughtful and well appreciated. In general (this doesn't apply particularly to the source mentioned in this talk page section), the entire article here needs to be rewritten from top to bottom with more reliance of reliable, secondary sources, not just for accuracy and currency of information, but also for due weight on which issues are the issues most closely related to the article topic and which relate more to the topics of other articles on Wikipedia. Thanks for the comments. -- WeijiBaikeBianji (talk, how I edit) 15:47, 7 April 2015 (UTC)

If I understand your comment correctly, you removed the section because you think it belongs in the Human intelligence article instead of this one. Is that correct? It seems more on-topic in this article to me, because this article includes the most discussion of other influences on IQ such as health and music lessons. 107.6.121.148 (talk) 20:21, 7 April 2015 (UTC)

We are all entitled to our own opinions, but meanwhile what do the sources say? In other words, if you read encyclopedic-style sources written by and for professionals that include articles about IQ testing (and I have some of those at hand in my office), what topics do those articles emphasize? Agreeing with you that the article by Johnson and others is a good article, what other sources do you recommend editors look at as we improve coverage of the topic of this article and other articles as Wikipedia continues to improve content quality? -- WeijiBaikeBianji (talk, how I edit) 21:36, 7 April 2015 (UTC)

You're being very vague. Can you please answer the question? When I asked why you removed the "brain anatomy" section, your answer (as far as I can tell) was that it belongs in the Human intelligence article instead of this one. If it does, it should be added to that article. Is that your opinion? 107.6.114.81 (talk) 21:59, 7 April 2015 (UTC)

?? That was a really simple question. If you can't provide a straightforward explanation for why you removed the section, or you don't want to, you shouldn't have removed it. I'm going to add it back. Please don't remove it again unless you can explain why you think it doesn't belong, without off-topic discussions about your long-term plans for the article. 107.6.121.142 (talk) 01:26, 9 April 2015 (UTC)

• There is a literature on this topic, and the Deary et al. article is a pretty high profile review of it, so I think the section should probably stay.·maunus · snunɐɯ· 01:34, 9 April 2015 (UTC)

• I've been looking for literature that shows what the scope of the topic "Intelligence quotient" is, as contrasted with the scope of "Human intelligence." I've found some good sources through the ScienceDirect online reference works. The articles I'll list here don't exhaust the articles that could help us determine the encyclopedic scope of this Wikipedia article on the topic here.

• *McCrimmon, Adam W.; Climie, Emma A.; Saklofske, Donald H. (2015). "Intelligence: Assessments of". In Wright, James D. (ed.). International Encyclopedia of the Social & Behavioral Sciences (Second ed.). Elsevier. pp. 283–289. doi:10.1016/B978-0-08-097086-8.25071-X. ISBN 978-0-08-097087-5. Retrieved 8 April 2015. {{cite encyclopedia}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysource= ignored (help); Unknown parameter |laysummary= ignored (help) – via ScienceDirect (Subscription may be required or content may be available in libraries.)

• *Resing, Wilma C. M. (2005). "Intelligence Testing". In Kempf-Leonard, Kimberly (ed.). Encyclopedia of Social Measurement. Academic Press. pp. 307–315. doi:10.1016/B0-12-369398-5/00083-9. ISBN 978-0-12-443890-3. Retrieved 8 April 2015. {{cite encyclopedia}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) – via ScienceDirect (Subscription may be required or content may be available in libraries.)

• *Colom, Roberto (2004). "Intelligence Assessment". In Spielberger, Charles Donald (ed.). Encyclopedia of Applied Psychology. Academic Press. pp. 307–314. doi:10.1016/B0-12-657410-3/00510-9. ISBN 978-0-12-657410-4. Retrieved 8 April 2015. {{cite encyclopedia}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) – via ScienceDirect (Subscription may be required or content may be available in libraries.)

• *Posthuma, D.; Rizzi, T. S. (2013). "Intelligence and the 'Intelligence Quotient'". In Maloy, Stanley; Hughes, Kelly (eds.). Brenner's Encyclopedia of Genetics (Second ed.). Academic Press. pp. 110–111. doi:10.1016/B978-0-12-374984-0.00805-6. ISBN 978-0-08-096156-9. Retrieved 8 April 2015. {{cite encyclopedia}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) – via ScienceDirect (Subscription may be required or content may be available in libraries.)

• *Atkinson, Leslie (2015). "Intellectual Functioning, Assessment of". In Wright, James D. (ed.). International Encyclopedia of the Social & Behavioral Sciences (Second ed.). Elsevier. pp. 249–254. doi:10.1016/B978-0-08-097086-8.21036-2. ISBN 978-0-08-097087-5. Retrieved 8 April 2015. {{cite encyclopedia}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysource= ignored (help); Unknown parameter |laysummary= ignored (help) – via ScienceDirect (Subscription may be required or content may be available in libraries.)

• *Johnson, E. (2012). "Intelligence Testing". In Chadwick, Ruth (ed.). Encyclopedia of Applied Ethics. Academic Press. pp. 744–751. doi:10.1016/B978-0-12-373932-2.00286-6. ISBN 978-0-12-373632-1. Retrieved 8 April 2015. {{cite encyclopedia}}: Invalid |ref=harv (help); Unknown parameter |laydate= ignored (help); Unknown parameter |laysummary= ignored (help) – via ScienceDirect (Subscription may be required or content may be available in libraries.)

• There are plenty more sources where these came from. -- WeijiBaikeBianji (talk, how I edit) 03:19, 9 April 2015 (UTC)

How does this relate to the section you removed? I asked you to please stay on topic in this discussion. Can you please try harder to do that? 107.6.121.135 (talk) 04:09, 9 April 2015 (UTC)

Ask that question of yourself. Are you checking any sources as you form a preference about what content to put here, or are you already locked into an opinion before you look at the sources? And, by the way, what general, encyclopedic sources specifically on the topic of this article do you recommend to other editors? -- WeijiBaikeBianji (talk, how I edit) 13:22, 9 April 2015 (UTC)

I don't understand what you're doing here. I asked you to justify your removing the "brain anatomy" section (and reverting me when I restored it). It would take no more than two or three sentences for you to answer that. Are you not reading what I'm asking, or is there some reason you can't answer it? 107.6.114.68 (talk) 15:11, 9 April 2015 (UTC)

Standard deviation calculation

The text indicates that the test is so designed that the standard deviation is fifteen points. While this may have been true at one point, it appears no longer to be true.

First, American Mensa (and, one hopes, they know at least a little bit about IQs) has chosen an IQ of 142 as the cutoff, which, per their intent, limits their membership to the top two percent of the population. Read another way, their assertion is clearly that persons possessing an IQ >= 142 represent 2% of the population. Citing the Q function table in an appendix to J. Melsa and D. Cohn, Decision and Estimation Theory (New York: McGraw-Hill, 1978), the closest figure to 2% (viz., 0.0202) corresponds to an argument of 2.05. In other words, Mensa asserts that 142 represents an IQ 2.05 standard deviations above the mean, i.e., the standard deviation is 42/2.05, or approximately 20.5.

Second, citing the standards maintained by a similar organization, known as the Six Sigma Society, we run into a rarefaction problem. Specifically, the value of Q(6) is less than 1.82 times 10 to the minus 9th power (sciz.,, most charts run only to Q(5.9), and its value is 1.82x10E-9, so Q(6) is necessarily slightly smaller). Given that the earth's population is approximately seven billion, this would allow for only three or four members—planet-wide—of the Six Sigma Society. Does the assertion that only three persons on the planet possess an IQ of 190 or greater even remotely make sense? If, citing the preceding argument, we adopt the figure of 20.5 for the standard deviation—in fact, let us use 20 for simplicity's sake—then we conclude that only three persons on the planet possess an IQ of 220 or higher, which is far more reasonable, if considering no more "reliable" source than a decades-old Guinness Book of World Records, which cited Kim Ung-Young of Seoul, who possessed an IQ of 210, as "the smartest person in the world." 73.49.1.133 (talk) 21:56, 5 June 2015 (UTC)

I'll check the article statements, which have long been based on reliable sources, if I remember correctly. -- WeijiBaikeBianji (talk, how I edit) 04:10, 6 June 2015 (UTC)

The standard deviation in IQ points is something that test makers can freely choose. Many tests use 15 points these days. The American Mensa accepts many different tests. The qualifying score is usually 130 or 132 on individually administered tests like the WAIS and the SB[8], that is, 2 SDs above the mean.--Victor Chmara (talk) 20:26, 6 June 2015 (UTC)

Thanks! When I joined Mensa many, many years ago, the flat statement on their Web site was that a minimum score of 142 was required; it said elsewhere that this corresponded to the cutoff of the 98th percentile, sciz., the point below which 98 percent of the population would score. It's interesting to see that they now cite 130 or 132 in many different contexts—as well as that, on a scale called Cattell, the minimum is 148! I imagine that corresponds to a standard deviation of 22.5, which is a peculiar number indeed.

I guess it's quite a separate question why so many people in Mensa were so very disturbed. Not only that, but you occasionally met someone who was obviously extremely intelligent but who—despite having two Ph.D.s, both of them earned—was employed as a stockroom clerk. In one extreme case, a supremely gifted gentleman was able within one evening to create a short story where he won a SCRABBLE game against the Devil with the score 1075-1074 (with all details explicitly specified) but was literally unable to respond to "Good evening" or "How 'bout those 'Skins [Washington Redskins, familiarly]?" at a party. These folks must've occurred as genetic accidents to families that had no idea of how to deal with them, making them end up somewhat like the (supposedly humorous) character Brick on The Middle. Admittedly, Brick doesn't have much of an intellect at all—instead having mastery of some mellifluous turns of phrase because of his perpetual nose-in-book state—but he does have a need for rather intensive psychiatry!

73.49.1.133 (talk) 20:21, 10 June 2015 (UTC)

Genetics and environment section - heritability

There is apparently a large amount of variation across the several wiki pages concerning human intelligence. I'm in the process of trying to bring them all in line with the data and with each other.

Right now, I'm only focusing on the Genetics and environment section of this page, and referring specifically to the issue of the heritability of intelligence. I wrote a bit on this subject in the Heritability of IQ talk page, and it's relevant here, so I will use some parts from what I wrote there.

First of all, there are several misinterpretations of data which misrepresent the overall scientific consensus and the reality of the issue as evidenced by a large number of studies, all of which have data that is broadly in agreement. Many of the misinterpretations appear to be a purposeful attempt to insert a biased view of the data into the page. For example, the first obvious error is the sentence "Heritability measures the proportion of 'variation' in a trait that can be attributed to genes, and not the proportion of a trait caused by genes." The first and second half of that sentence directly contradict. Heritability does measure the proportion of a trait caused by genes, but heritability applies to populations. And in populations there are variations in phenotypic traits between individuals... heritability measures how much of that variation is caused by genetics or, in other words, the proportion of a trait caused by genes.

The second obvious error is the most damaging one. It's the sentence: "The general figure for heritability of IQ is about 0.5 across multiple studies in varying populations". This sentence conflicts with the overwhelming majority of studies and data on the subject. The .5 number is considered an absolute lower-bound for the heritability of IQ (see: http://www.ncbi.nlm.nih.gov/pubmed/21826061 - note that "fluid-intelligence" is what is tested during IQ tests). Since the citation is a book (Behavioral Genetics - https://books.google.com/books?id=OytMMAEACAAJ), which can't be viewed anywhere online, I have no way to check their sources to see if this is a misquotation and the book simply mentioned .50 as a lower-bound or not. However, after researching the data in the 'Behavior Genetics' book that the citation referred to, I found it comes from studies done on children. The heritability of IQ changes dramatically as a person ages from childhood to adulthood, so any studies on the heritability of IQ which were done solely on children should be labeled as such and NOT included in data which could be assumed to be the final adult heritability number, since they will be significantly lower.

Several meta-studies and authoritative sources conflict with the .5 number for adult intelligence heritability as well. For example, "Mainstream Science on Intelligence", which was a statement paper signed by 52 university professors specializing in intelligence and related fields, and has this to say on the heritability of IQ: "Heritability estimates range from 0.4 to 0.8 ... indicating genetics plays a bigger role than environment in creating IQ differences"

But far better than that is "Intelligence: Knowns and Unknowns". In 1995, the APA published what was meant to be a non-political "authoritative report" on the issue of intelligence. Basically it was to be a statement on the consensus of the field of professional psychology on the issue of intelligence, straight from it's leading members. Here's what it says on the heritability of IQ (which may explain why .5 is mistakenly used sometimes):

"Across the ordinary range of environments in modern Western societies, a sizable part of the variation in intelligence test scores is associated with genetic differences among individuals. Quantitative estimates vary from one study to another, because many are based on small or selective samples. If one simply combines all available correlations in a single analysis, the heritability (h 2) works out to about .50 and the between-family variance (c 2) to about .25 (e.g., Chipuer, Rovine, & Plomin, 1990; Loehlin, 1989). These overall figures are misleading, however, because most of the relevant studies have been done with children. We now know that the heritability of IQ changes with age: h 2 goes up and c 2 goes down from infancy to adulthood (McCartney, Harris, & Bernieri, 1990; McGue, Bouchard, Iacono, & Lykken, 1993). In childhood h 2 and c 2 for IQ are of the order of .45 and .35; by late adolescence h 2 is around .75 and c 2 is quite low (zero in some studies). Substantial environmental variance remains, but it primarily reflects within-family rather than between-family differences.

These adult parameter estimates are based on a number of independent studies. The correlation between MZ twins reared apart, which directly estimates h2, ranged from .68 to .78 in five studies involving adult samples from Europe and the United States (McGue et al., 1993). The correlation between unrelated children reared together in adoptive families, which directly estimates c2, was approximately zero for adolescents in two adoption studies (Loehlin, Horn, & Willerman, 1989; Scarr & Weinberg, 1978) and. 19 in a third (the Minnesota transracial adoption study: Scarr, Weinberg, & Waldman, 1993). "

Another problematic sentence is "Debate is ongoing[weasel words] about whether these heritability estimates are too high, owing to inadequate consideration of various factors—such as the environment being relatively more important in families with low socioeconomic status, or the effect of the maternal (fetal) environment.

In fact, debate is ongoing in every aspect of every subject in the world. That is what we call science. Nevertheless, that sentence needs to be removed since it implies, inaccurately, that 1)there is some coherent trend toward the belief that current heritability measurements are too high; and that 2)there are proposed hypothesis for why they're "too high".

The entire Individual genes section is poorly written and reflects an obvious bias. It appears to imply that genes have little effect on intelligence. But intelligence, like height, is a polygenic trait. It's influenced by a large number of genes, so individual genes invariably will have a very small effect on their own. This by no means suggests anything about the amount of influence genes as a whole have on intelligence. Bzzzing (talk) 19:29, 7 December 2015 (UTC)