Talk:Intelligence quotient

Low IQ?

Why does this image set the upper limit for IQ scores at 130? isn't it a bit silly to set the cut off so low? File:IQ-70to130-ColorBars.png

because the exact distrubtion isn't know above 130 and below 70, but for sake of making a pretty picture, I can expand it to 55-145. --Rikurzhen 04:51, Jun 10, 2005 (UTC)

What's the data source for this graph? Is it just an idealized distribution, or is it based on actual numbers from a study? If so, which study? The image page says I created with R >IQ<- 70:130 >p<- dnorm(IQ,mean=100,sd=15) >plot(IQ,p,type = "h", col=c(rep(2,15),rep(3,15),1,rep(4,15),rep(6,15)), lwd=3) ) - Why those values? (BTW, a very nice looking chart). Thanks, -Willmcw June 30, 2005 19:51 (UTC)

The article doesn't mention Verbal IQ and Performance IQ.

Psychologists use these terms a lot. I'd like to see an explanation of them.

24... The definition of consensus is something like "agreement of the majority in sentiment or belief." The sentence is question is a description of the "Mainstream Science on Intelligence" piece published in the Wall Street Journal following the publication of the Bell Curve. It was signed by a majority of the members of the intelligence research community at the time. I'm changing the problem sentence to reflect this fact.

"It was signed by a majority of the members": This is not correct. The full story of the WSJ statement is told in the Intelligence journal article written by the statement's coordinator. A majority of respondents (52 of 100 respondents to 131 invitations) signed the statement. There are certainly more than 100 (or 131) members of the intelligence research community, though I do not know the actual number. Several respondents declined to sign despite agreeing with the statement, for various reasons detailed in the article. The claim that the statement represents a majority is technically true, though whether this majority extends to the field as a whole depends on the credence one lends to the coordinator's claim that she attempted to assemble a representative sample of the field, since her own beliefs are clear. --DAD 08:07, 16 Dec 2004 (UTC)

Moreover, allthough the Bell Curve is not mentioned until the "Race and IQ" section, this topic is a very small portion of the book, which focuses more on the rise of meritocracy. For a discourse on race and IQ it would better to discuss a book like Arthur Jensen's "The G Factor: the Science of Mental Ability," which more directly addresses the question.

Please let me know if you have evidence to the contrary. --Rikurzhen 07:04, Apr 5, 2004 (UTC)

There are two main quotiens, one with average=100, stddev=15, (aka. European IQ) and the other with average=100, stddev=24 (aka. US IQ)

Numbers on page reflects which one ?

"is a measure believed to be of general cognitive ability". Is believed by who? Is there controversy about this? (There certainly should be controversy, since Binet, who invented IQ in the first place, certainly did not believe this, and the know-nothing bozos at Stanford who apparently originated the belief published no scientific evidence to back it up.)

This needs fixed. There is little controversy. Standardized test have to corelate to quantifiable data. What they are standardized against should be noted here, and is noted in the studies that are used to support, create, and tweak the tests. IQ is not a measure believed to" be anything. It is "demonstrated as correlating to" a number of factors. The contoversy only arrises when people subjectively and unscientificly extend those to intelligence without a scientific definition of intelligence. The one in my old psych book was something like "the skills and abilities needed to survive and prosper in a specific environment". When these things are not noted It either sounds like one is calling others dumb or is used to call others dumb, as was often the case in the early years of the stanford test. I wil try to correct this when I find my psychology book and some time. WilliamJuhl 03:49, 2 Apr 2005 (UTC)

I believed that IQ was a scale that stopped when you reached 18yrs old. It is achieved over actual age in terms of intelligence e.g. smart as a 10yo at 10yo IQ is 100, smart as a 15yo at 10yo then IQ is 150.

I removed this statement:

Around 3% of the people are said to be highly intelligent, of whom 1% reaches the level of genius.

because (aside from being ungrammatical) it doesn't say anything. What does "highly intelligent" mean, or what does "genius" mean? If you define these as simply "in the 97th (and 99th) percentile of IQ", then the statement is a tautology. If you don't define them, then the statement is an unattributed opinion. Something like "Some sociologists call IQs in the 99th percentile 'genius' level", then it becomes a true statement about sociologists, but I'm still not certain that it has any real information content. --Lee Daniel Crocker

Yet, some info should be included to present what is the corelation between iq and number of persons having it. Ex:[1]

Does anyone else think that we should mention Isaac Asimov's (someone famous for his high IQ) essay, "Thinking About Thinking"? --BlackGriffen

The external links don't work any more. It appears that one must buy the articles to be able to download them. --RS

There have been recent statements saying that men and women share the same average IQ (100) but have different standard deviations (higher for men) - meaning that there are more male geniuses and more male imbeciles. Can anyone quantify/clarify/know of sources for this? (I can write it up if someone has the info). Mat-C 17:51, 17 Apr 2004 (UTC)

Very informative the last paragraph about online tests. I have filed the test from tickle.com with random data, and got an IQ of 84 and the folowing characterization: "Your Intellectual Type is Word Warrior. This means you have exceptional verbal skills. You can easily make sense of complex issues and take an unusually creative approach to solving problems. Your strengths also make you a visionary. Even without trying you're able to come up with lots of new and creative ideas. And that's just a small part of what we know about you from your test results. " . So true, so very true. -- Stelian

I took the tickle test and got 135, "Visionary Philosopher". I think what's going on is that the number is the hard data and that the verbal description is a feel-good statement on what areas you scored highest in. So your random entries rated you the IQ of an idiot with advanced mad cow disease, but most of the right answers just happened to fall in the verbal section. Thus, you are an idiotic word warrior. ;) Tom S.

People volunteering to take IQ tests NOT likely to be above average

I have a minor beef with this conclusion:

"It is therefore recommended not to take online IQ tests as a true judge of one's IQ, even when considering that people who take these tests voluntarily are likely to be above average anyway."

Lately I've been noticing a lot of advertisements for online IQ tests replacing 'punch the monkey and win $100' web popup ads. The new IQ test ads feature a photo of a typically haggard Albert Einstein and do not offer prize money, only a test score. These ads are designed to entice as many people as possible to click them. In other words, they are specifically targeted to the average. At least as far as the population pool of web surfers goes, it would seem that the desire to voluntarily take online IQ tests is an average desire, and not an indicator of an above average IQ.

Yes, but your title is misleading. You imply with your title that volunteering for an IQ test places you at or below average. What your conclusion (and I agree with you) seems to say is that simply volunteering for an online IQ test does not make you automatically above average. That DOES make sense. Tom S.

Internet users in general have above-average IQs, globally speaking. The lowest-IQ populations tend to be in the poorest countries. It isn't important, anyway, because these tests usually don't calculate their scores based on anything resembling a normal curve, so it's hard to make any good conclusions based on the data. I'm going to remove the claim because there's no really good evidence on either side. If anyone would like to provide some specific study showing self-selection for high-IQ individuals in online tests (or voluntary tests in general) or to elaborate further on some specific reasoning behind this conclusion, feel free, but until then I just think this shouldn't be in here. - EHS

I also believe that Internet IQ scores are biased. It takes a certain level of self esteem to take an IQ test voluntarily. Many people do not like to humiliate themselves when they doubt their own intellegence. Even when the test are anonymous, some people just don't want to face the truth. People who take the test voluntarily have confidence in themselves. They probably take the test as a self-validation to see if they are as smart as they think they are. No one wants to take an IQ test to prove how dumb they really are. I think this is just a matter of psychology. Those who take the test on-line may impact the bell curve and thus the score is inaccurate. I disgree with the argument that since IQ test ads are targeting average people recently, then the average people would take the test. I also see Mecedes Benz advertisment on many newspapers, that does not mean I would buy one. Kowloonese 00:23, Feb 1, 2005 (UTC)

OK you lost me. Internet scores are biased because the person taking the test doesnt want to find out how dumb he is? How'd you reach that? If the REASON for taking an IQ test has any adverse effect on the accuracy of the results, then why isnt that in the article? Tom S.

"mensa hall of fame"

An anonymous user (User:195.229.241.181) added the following information:

Mensa Club Hall of the fame

Olivier Roberts - 33 (2003) U.S
RIchard Huts    - 33 (2003) U.K
Shiny Mathews   - 28 (2004) Ind
Gregory Peters  - 27 (2004) Hungury

I don't know where it fits..It was added in the lead section, where it definitely does not belong. I'll post a message on the anonymous user's talk page. — David Remahl 11:30, 20 Sep 2004 (UTC)

More added by User:195.229.241.182, note that these numbers aren't consistent with the above:

Mensa Hall of fame

oliver peter - 33 ( US)
Gregory peck - 33 (UK)
Shiny mathews - 28 (Ind)
Johan Yusuf   - 27 ( SYR)

— David Remahl 11:54, 20 Sep 2004 (UTC)

Sex differences in the brain

My english is not that perfect and I do want to add something to this article. I'm appealing that women and males do differ of some short in thinking. Most of us agree with that however I argue that the differences are hardwired and not influenced by culture. I'm asking someone to read the following article for more information. And I be grateful if some information of it is used in the article. If you need more information just P(ublic)M me. --A. 13:04, 21 Sep 2004 (UTC)

I removed a claim that most intelligence researchers support a non-social cause of racial IQ disparity. This seems to have been based on an article that originally appeared in the Wall Street Journal.

Even a cursory review of material online shows the claim to be dubious. The revised version of the book "The Mismeasure of Man" disputes many of the arguments in "The Bell Curve". It is clear experts in the field have differing opinions.

The Wikipedia article "Race and Intelligence" covers this in much more detail providing some very interesting and persuasive counter-examples to the position stated in "The Bell Curve".

I think the section on Race and Intelligence in this article should be dropped and replaced with a link to the article "Race and Intelligence" (any useful information that would otherwise be dropped can be moved into "Race and Intelligence").

--Robert Brockway 05:23, Nov 16 2004 (UTC)

Seeing no objection to the above proposal, I've moved the Race and IQ section to Race and intelligence. The first paragraph dealt with The Bell Curve, which is adequately handled in its own article, and I moved one sentence to Charles Murray (author). -Willmcw 09:59, 16 Dec 2004 (UTC)

--==== SO IN THE END ====--

So in the end, IQ measures basically how many questions you can answer right... hmm, doesn't really sound much like a way to measure your intelligence- it sounds more like HOW MUCH YOU KNOW. As you know, there are different types of intelligences, and it would seem to make more sense to say that there are simply too many factors to consider to put together a "meansurement" for your intellience. What about athletes? And artists? Everybody thinks differently, and IQ tests don't leave any room for interpretative reasoning.

Try TAKING AN IQ TEST! Don't judge in ingnorance, my friend. It is not testing how much you know. It is testing how you answer various questions. Even if you get the answer wrong, the answer you give will reveal what part of the brain you're thinking with to some degree. Just try taking one, please? Tom S.

-Yes it does. Have you ever even taken an IQ test? It doesn't ask you to recite a bunch of dates. Just because it's a test doesn't mean it's asking for rote memorization.

Advertisements in External Link section

I followed a link in the external link section and found the following page at http://members.chello.nl/p.cooijmans/gliaweb/tests/boostiq.html This page indicates that IQ score from this website can be raised for a fee. That raised a question of legitimacy of this website and its tests. The intention of including the link in this wikipedia article is questionable too. Kowloonese 00:05, Feb 1, 2005 (UTC)

Normally distributed

"Tests are designed so that the distribution of IQ scores is more-or-less Gaussian, that is to say that it follows a bell curve."

Does anyone else think that it would be useful to add the term 'normally distributed' to this sentence. I think Gaussian is used less than Normal in common usage. At least where I'm from.--Commander Keane 11:32, 7 Feb 2005 (UTC)

Validity of specific tests

I added this section as part of cleanup efforts, merging from Online IQ Test Validity, however, I wanted to draw attention to the fact that the information in that article was unsourced. Demi ^T/_C 23:40, 2005 May 27 (UTC)

Religiosity and intelligence

I removed this section again, because I don't think we should by synthesizing material from "what we expect" a main article to become. The referenced article does not establish sources for any correlation of religiosity and IQ, and while it seems like it will pass VFD, I'm not sure it will. When there's sufficient material from this "main article" to include here, it can be done then. Demi ^T/_C 19:12, 2005 May 28 (UTC)

And never take an IQ test that asks for your religiosity or politics. The LOWEST I have ever measured in tests that do not is 127, and I measured 135 on Tickle. I'm curious as to what my ACTUAL IQ is... but back on track now; I took an IQ test on one of these links. Before giving me my score, it asked for some "demographic information". I chose the ultimate PC dumb guy: white, male, christian right-winger. I scored 122. Now if I could only remember which link I followed... Tom S.

Neurobiology of Intelligence: Science and Ethics

From Gray & Thompson (2004) [2]... stuff we should integrate here and/or brain size and intelligence. --Rikurzhen 07:40, Jun 9, 2005 (UTC)

Neurobiological determinants of intelligence as measured by IQ:

Posterior lesions often cause substantial decreases in IQ. Duncan and colleagues suggested that the frontal lobes are involved more in Gf and goal-directed behaviour than in Gc (Fig. 2). In addition, Gf is compromised more by damage to the frontal lobes than to posterior lobe...
MRI-based studies estimate a moderate correlation between brain size and intelligence of 0.40 to 0.51
g was significantly linked to differences in the volume of frontal grey matter, which were determined primarily by genetic factors... the volume of frontal grey matter had additional predictive validity for g even after the predictive effect of total brain volume was factored out
Only one region is consistently activated during three different intelligence tasks when compared to control tasks...The surface features of the tasks differed (spatial, verbal, circles) but all were moderately strong predictors of g (g LOADING; range of r, 0.55–0.67), whereas control tasks were weaker predictors of g (range of r, 0.37–0.41). Neural activity in several areas, measured by a positron emission tomography (PET) scan, was greater during high-g than low-g tasks.
Speed and reliability of neural transmission are related to higher intelligence (reviewed in Refs 15,20). Early neuroimaging studies using PET found that intelligence correlated negatively with cerebral glucose metabolism during mental activity54 (for a review, see Ref. 55), leading to the formulation of a 'neural efficiency' hypothesis...
Gf is mediated by neural mechanisms that support the executive control of attention during working memory...greater event-related neural activity in many regions, including the frontal, parietal and temporal lobes, dorsal anterior cingulate and lateral cerebellum. Crucially, these patterns were most distinct during high-interference trials, even after controlling for behavioural performance and for activity on low-interference trials within the same regions
RAPM scores obtained outside the scanner predicted brain activity in a single left parietal/temporal region, and not in the frontal lobes.
An exploratory fMRI study60 (n = 7) indicated that parietal areas are involved in inspection time tasks, specifically Brodmann area (BA) 40 and the ventrolateral prefrontal cortex (BA47) but not the dorsolateral prefrontal cortex

Behavioral Genetics of IQ:

Monozygotic twins raised separately following adoption show a correlation of 0.72 for intelligence
For 48 identical twin pairs separated in early infancy and reared apart, Bouchard et al.83 found remarkably high between-twin correlations for verbal scores on the WAIS (0.64) and for the first principal component of special mental abilities (0.78)
Psychometric g has been shown to be highly heritable in many studies, even more so than specific cognitive abilities (h2 = 0.62, Ref. 87 compare with Ref. 88; h2 = 0.48, Ref. 89; h2 = 0.6–0.8, Refs 90,91)...
Intriguingly, the influence of shared family environments on IQ dissipates once children leave home — between adult adoptive relatives, there is a correlation of IQ of -0.01

Molecular Genetics of IQ:

Chorney et al.104 discovered an allelic variation in a gene on chromosome 6, which codes for an insulin-like growth factor-2 receptor (IGF2R), that was linked with high intelligence...
Later studies identified a second IQ-related polymorphism in the IGF2R gene, and others in the cathepsin D (CTSD) gene, in the gene for an acetylcholine receptor (CHRM2)106, and in a HOMEOBOX GENE (MSX1) that is important in brain development107, 108.
Influence of each polymorphism was minimal — variants of CHRM2 accounted for a range of only 3–4 IQ points, whereas different forms of CTSD accounted for about 3% of the variation between people...None of these associations has yet been replicated by other research groups
Some patients with microcephaly also possess the ASPM mutation, indicating that a shortened version of the gene might lead to the development of fewer cerebral neurons and a smaller head.
Polymorphism in the human brain-derived neurotrophic factor (BDNF) gene is associated with impaired performance on memory tests
Catechol-O-methyltransferase (COMT) gene influences the activation of working memory circuits. COMT polymorphisms seem to be highly specific to some prefrontal cortex-dependent tasks in children.
Dopamine receptor (DRD4) and monoamine oxidase A (MAOA) polymorphisms are associated with differences in performance and brain activity during tasks that involve executive attention

Most of these have much to fine detail for a general encyclopedia. Especially the last and last section which is completely uninteresting for anyone except for an active researcher and he probably already knows it all. We should not paraphrase every article ever done in the overview article. Ultramarine 22:22, 16 Jun 2005 (UTC)

Mainly, I was thinking about this stuff for brain size and intelligence, which I think should be renamed. See the talk page there. --Rikurzhen 04:54, Jun 17, 2005 (UTC)

Illogical

The section regarding brain size & IQ is pure intellectual chicancery. High IQ does not mean good health, not in the slightest. Why does this explicate why several 'geniuses' suffer immense bouts of depression? Something needs to be elucidated regarding this matter, what do you think? The correlational studies linking IQ to health seem, at the least, good fodder to contradict, so as to provide a neutral point of view.

Income numbers

The paragraph on sibling income had a strange transition, starting from Murray 1998's results and then immediately stating:

However, these differences are less impressive when considering that in 1993 the average family income was $61,800 while the average family income of the richest 10% was $172,400. ^[3] (Note these income values are larger than those from Murray's study, possibly because these values include income other than wages. Murray found average family incomes at five IQ tiers of $53,000 for the top 10 percent of IQ, $45,000 for the next 15 percent, $37,000 for the middle 50 percent, $23,400 for the next 15 percent, and $12,000 for the bottom 10 percent.)

The data cited in the paragraph refer to individual income, consistent with the question being addressed in the paragraph, which is, "Does IQ make any difference at the highest levels?" Specifically, the question is, "Does IQ make any difference in income at the highest levels?" The average family income data are unrelated to that question. Also, as the author seems to recognize, they cannot be meaningfully compared to the Murray study. I've replaced them with the actual reported mean individual earnings ($23,703) for the normal control group in the study. I'm also not a fan of the editorializing "these differences are less impressive," which is baldly POV. --DAD 30 June 2005 01:20 (UTC)

These edits were recently reverted "because people have families." In keeping with that idea, I've left in the Murray family income numbers, which I agree are relevant, and removed the editorial comment. I'll be happy to see the remaining fragment

In 1993 the average family income was $61,800 while the average family income of the richest 10% was $172,400.

included as soon as we have a citation for those data. (Still, it's not clear why such additional family data are needed, unless there is a (published) claim that Murray's numbers are incorrect; we now have the family part covered.) I request either a Talk entry for such significant reversions or a more thoughtful edit comment. --DAD 1 July 2005 07:30 (UTC)

Bell / Normal curve

The spread of people along the IQ continuum, from low to high, can be represented well by the bell curve (in statistical jargon, the "normal curve"). Most people cluster around the average (IQ 100). Few are either very bright or very dull: About 3% of Americans score above IQ 130 (often considered the threshold for "giftedness"), with about the same percentage below IQ 70 (IQ 70-75 often being considered the threshold for mental retardation). [ http://www.mugu.com/cgi- bin/Upstream/Issues/bell-curve/support- bell-curve.html]

Can we use this quote? Is it neutral, objective, consensus, mainstream, or what? Uncle Ed July 6, 2005 15:34 (UTC)

It's nearly definitionally true. IQ tests are normalized so that the mean is 100, the standard deviation is 15, and the distribution is normal. That fact is uncontested, although it might be argued that we don't know if intelligence is normally distributed. However, biological correlates of IQ are (approximately) normally distributed, as are most quantitative traits (e.g. height, weight, etc). --Rikurzhen July 6, 2005 21:59 (UTC)

Online tests

Why is this even here? Pardon if I missed something, but I don't see why tests that have nothing to do with IQ (such as the Tickle) are mentioned here. Peoplesunionpro July 6, 2005 15:37 (UTC)

Agree. I'm also bothered that the g-loadings are uncited. Go for it! --DAD ^T 6 July 2005 21:53 (UTC)

i.q. for different ages

Does anyone know the normal i.q. for a fourteen year old?