Talk:Neuroscience and intelligence

Untitled

Should we change the title to Neurobiology and intelligence in order to expand the scope and future-proof the article. That would cover both volumentric as well as functional assays. --Rikurzhen 05:01, Jun 9, 2005 (UTC)

Sounds like a potentially more interesting and informative article, one which I would like to read. Maybe something else than neurobiology (e.g., neuroscience), but I certainly advocate broadening the scope from brain size. Arbor 07:33, 10 Jun 2005 (UTC)

Biased POV

This article has a very pro headsize correlates with IQ viewpoint. The MRI studies did not show a high correlation at all, and there are as many (if not more) recent studies which have found that the genes associated with larger skulls/brains were not associated with higher intelligence. I will try and find the study (I believe it was in an Australian newspaper. After all if it was true then Einstein should have had one of the largest brains ever measured- he didn't. So at best, the correletion is weak. —Preceding unsigned comment added by 80.229.27.251 (talk) 12:36, 10 September 2007 (UTC)

This article is terribly biased, most of the claims based on evolutionary biology have been largely (and for awhile now) discredited. For a round-up: see "Race" Is a Four-Letter Word by Brace. Pages 240 - 260 (that area). It's heavily referenced. Downchuck (talk) 04:54, 28 October 2009 (UTC)

Actually it was proven that Einstein's Brain involved an extremely enlarged sector of the brain which generally deals with math. http://en.wikipedia.org/wiki/Albert_Einstein's_brain —Preceding unsigned comment added by 192.139.153.30 (talk) 18:15, 17 January 2008 (UTC)

(The paragraph which says "I believe it was in an Australian newspaper" is extremely important. The media is widely biased toward the view that intelligence and other cognitive abilities are mostly environmental malleable; and lay people generally naively believe that human cognitive ability can be widely influenced through training. The fields of Psychometry and Neuroscience tend to obscure completely contrasting findings in scientific-hifalutin language in order to hide the facts from an easily offended public. The experiment to test the correlation between IQ and brain/cranial size/volume/weight/circumference is a relatively simple experiment to do to good and objective statistical significance. Indeed the resources and sophistication needed to try debunk these simple experiments pull out far more rabbits than the experiments themselves. I would invite anyone with a staunch belief that brain size does not correlate substantially with cognitive ability, to perform the experiment on any group of people. Indeed there should never have been a debate about this question at any time in human history. The correlation is indeed blatantly apparent. What led some reporter to print something in some newspaper is a subject of the social ills of our society that deserves an entire Wikipedia chapter in its own right.)

Talk pages should deal with the article rather than the topic it is about, and any changes to the article would need to be based on reputable published sources. Also, please remember to sign your talk page edits by typing ~~~~ at the end. Looie496 (talk) 18:42, 28 October 2009 (UTC)

False Citations

Many of the citations on this page are false and do not represent the information presented; specifically the information relating Africans and Brain size. I checked the sources and they have nothing to do with this, what-so-ever! Further, the information on height and intelligence has no references and I suspect that it may be bogus.

If I was not a Wikipedia novice I would see to it that you were all banned for spreading vicious rumors.

I will attempt to remove this information again!! —The preceding unsigned comment was added by 70.68.179.142 (talk) 11:24, 25 December 2006 (UTC).

Yes, I agree; many of the citations are false.—Preceding unsigned comment added by 89.107.243.1 (talk • contribs)

Gray & Thompson (2004)

From Gray & Thompson (2004) [1]... stuff we should integrate here --Rikurzhen 04:07, Jun 22, 2005 (UTC) Neurobiological determinants of intelligence as measured by IQ:

1. 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...
2. MRI-based studies estimate a moderate correlation between brain size and intelligence of 0.40 to 0.51
3. 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
4. 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.
5. 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...
6. 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
7. RAPM scores obtained outside the scanner predicted brain activity in a single left parietal/temporal region, and not in the frontal lobes.
8. 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

---

"[...] showed that frontal gray matter volume was correlated with g and highly heritable."

What is g? Eighty 10:51, 26 August 2005 (UTC)

g is a general measure of overall intellegence... I think it is a Spearman thing, look at http://www.psych.utoronto.ca/~reingold/courses/intelligence/cache/1198gottfred.html. Dark Nexus 19:52, 1 January 2006 (UTC)

This sounds wrong to me "smaller brains might be advantageous from an evolutionary point of view if they are equal in intelligence to larger brains." Surely if intelligence is equal a smaller brain is definitely an evolutionary advantage due to its lower energy usage. I think it should read "smaller brains might be advantageous from an evolutionary point of view EVEN IF they are LOWER in intelligence than larger brains." —Preceding unsigned comment added by 203.146.247.78 (talk • contribs)

Intelligence and brain energy (wattage) use

Is there known to be a specific correlation? I thought I read in one research paper that, in humans, brains of higher IQ tended to use less energy because they were more efficient. But I cannot find this source... and it goes against the general biological idea that higher intelligence requires more energy use from the brain. It's also confusing when debating the 'race and intelligence (genetics)' issue, because it seems odd that some population groups would average such below average IQs when there would be much to gain in metabolic efficiency in having higher IQs. Peoplesunionpro 17:08, 15 April 2006 (UTC)

Jung, Haier et al, Brain Structure

For brain structural variations other than raw brain size, we might want to sift through some of the material covered by e.g. Haier and Jung relating to brain structure and parieto-frontal integration theory. It's been ages since the brain/intelligence people relied on total size. Ahazred8 19:12, 23 September 2007 (UTC)

Added the brain size increase controvercy into the article

I include the theories I know - the tools theory (I have no sources for this one. It what I was taught in school and learned as a boy from boys science books), both increased memory theories and "I Run, Therefore I think".

I know for sure there's a school that relates the brain size expansion to social skills requirements, but I failed to locate any specific paper, so I did not include that.

When this section is complete - I think it should be in its own article, "Humanoid brain size increase process through evolution" or something.

Zarnivop (talk) 08:14, 15 September 2008 (UTC)

Tools and Brain Size Relationship is a Tautology?

"The cause for this increase in brain size is disputed. While it is popular to associate the increase in brain size with tools usage, this idea is fundamentally flawed and regarded as tautology: the use of tools requires a larger brain, but before the brain is improved it is impossible to use tools."

This is the sentence that I found and improved its grammar. But I don't see how it is really a tautology. What if people with larger brains used tools better, and that improved their reproductive fitness? How would that be a tautology?

--Zoid62 (talk) 19:12, 29 July 2009 (UTC)

I agree with you, and since no source is given for that statement, I would be in favor of removing it. It looks like a simple failure of understanding by an earlier editor. Looie496 (talk) 19:29, 29 July 2009 (UTC)

Who is checking the references here for fit with WP:MEDRS guidelines?

This would appear to be an article about a medicine-related topic, so I figure the article should be edited in accordance with Wikipedia guidelines on identifying reliable sources for medicine-related articles. Is anyone checking sources here? 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. -- WeijiBaikeBianji (talk) 13:37, 28 July 2010 (UTC)

If you look at the article's history, it hasn't been edited significantly since last year. Any improvements you come up with you'll probably have to make yourself, and you're certainly welcome to do so. Looie496 (talk) 20:59, 28 July 2010 (UTC)

I'll keep your advice in mind, and start digging into the sources. -- WeijiBaikeBianji (talk, how I edit) 04:08, 5 November 2010 (UTC)

Rushton, Jensen and the gang

Rushton, Jensen and the hereditarian gang are not neuroscientists and there is no indication that their publications carry any weight in the field of neuroscience. Their speculations made up almost half the article's body - an extreme case of undue weight given to what is at best a fringe view. Unless mainstream neuroscience sources cite them they should be left out entirely. I have removed them from the section on brain size untill such sources are provided and a shorter summary of their ideas could be written. ·ʍaunus·snunɐw· 16:35, 24 October 2011 (UTC)

Regarding the question in your edit summary ("who is checking references...?"), the answer is, nobody. I have the article on my watchlist and try to keep it from getting even worse than it already is, but improving it is not on the cards for me. If you have any urge to remove unencyclopedic material from the article, I would be supportive. Looie496 (talk) 17:07, 24 October 2011 (UTC)

I think you meant to respond to the above section? I have removed some unencyclopedic information - I am glad you ae supportive.·ʍaunus·snunɐw· 17:18, 24 October 2011 (UTC)

Not sure what is supposed the wrong with the studies. No evidence has been given for that these peer-reviewed stuides are fringe views. If nothing else the literature reviews should be added back. Acadēmica Orientālis (talk) 17:36, 3 February 2012 (UTC)

If keeping only the reviews, I propose this text:

"Rushton and Ankney (2009) in a literature review write that in 28 samples using brain imaging techniques the mean brain size/g correlation was 0.40 (N = 1,389). In 59 samples using external head size measures it was 0.20 (N = 63,405). In 6 studies that corrected for that different IQ subtests measure g unequally well, the mean correlation was 0.63. Some studies have found the whole brain to be important for g while others have found the frontal lobes to be particularly important. Two studies founds correlations of 0.48 and 0.56 between brain size and the number of neurons in the cerebral cortex (based on counting in representative areas."

Rushton and Jensen in a review (2010) write that the brain is metabolically demanding. In rats, cats, and dogs it uses about 5% of the body's energy. In primates, 10%. In humans, 20%. Larger brain are also expensive evolutionary since they take time to grow and requires larger bodies to produce and sustain them. An increased brain size would not have evolved unless it gives great evolutionary advantages. Brain size and brain-to-body mass ratio has been increasing for the last 575 million years. Mammals living 65 million years ago had substantially lower brain size than today. The hominid brain has tripled in size over the last 3 million years from Australopithecus to Homo erectus to modern humans. An earlier claim that Neanderthals had on average larger crania than anatomically modern humans has been invalidated and the brain to body size for Neanderthals was slightly smaller. Any decrease in average brain size over the past 35,000 years has likely been paralleled by a corresponding decrease in average body size suggesting no change in the ratio of brain to body size.

Y The content in question was significantly edited by Acadēmica Orientālis (talk · contribs) when editing as Miradre (talk · contribs): [2]. aprock (talk) 18:21, 3 February 2012 (UTC)

So? Do you have any concrete objections to adding the material from the review studies above? Acadēmica Orientālis (talk) 18:24, 3 February 2012 (UTC)

Certainly. You are continuing to promote a point of view by giving undue weight to controversial sources. See [3], [4], [5]. aprock (talk) 18:28, 3 February 2012 (UTC)

You given no evidence that this material is controversial. If you have this, then controversy in itself is not a reason for exclusion. You can add your sourced views also in order to achieve NPOV. There is no mention of race anywhere is in this material which only deal with IQ and brain size.Acadēmica Orientālis (talk) 18:33, 3 February 2012 (UTC)

We don't need to provide more evidence that Rushton is controversial fringe this has been done to death - you know he is and you know we know - and Arbcom knows. Rushton is fringe. And he is not a neuroscientist. And whether these particular papers mention race is irrelevant - your agenda is obvious and well known. ·ʍaunus·snunɐw· 20:35, 3 February 2012 (UTC)

Do you have source for that the Arbcom consider him fringe? Rushton is an IQ researcher who have done a lot of research in this area. Ad hominem is not a valid scientific argument. Acadēmica Orientālis (talk) 20:38, 3 February 2012 (UTC)

Neither is WP:IDIDNTHEARTHAT. You are wasting your and our time with this nonsense.·ʍaunus·snunɐw· 20:43, 3 February 2012 (UTC)

• The burden of evidence is on the one who wants to include. So for this argument to advance show us some examples of recent mainstream sources preferably Review articles or textbooks about the topic of neuroscience and intelligence that refer to Rushton's work. ·ʍaunus·snunɐw· 20:44, 3 February 2012 (UTC)

• I have cited review articles. Rushton and Jensen have published in important psychological journals. There are those who disagree but that they are there at all show that they are taken seriously. Here are two articles in Nature Reviews citing the brain size and intelligence literature review artcle: http://www.nature.com/nrn/journal/v11/n3/abs/nrn2793.html http://www.nature.com/nrn/journal/v12/n4/abs/nrn3000.html

• Have you read the sources? Neither of the abstracts you link to indicate that the articles discuss how brain size relates to intelligence. One is clearly labeled as an opinion piece. If you actually have access to a copy of the Deary article, I don't see anything wrong with a brief summary in the Anatomy section. Without access to the article, it's really hard to evaluate. aprock (talk) 20:57, 3 February 2012 (UTC)

• My point here is that Rushton is not ignored by scientific community and not cited by reviews which was the claim above. Acadēmica Orientālis (talk) 21:03, 3 February 2012 (UTC)

• Does Deary mention Rushton? Could you provide the excerpt? aprock (talk) 21:05, 3 February 2012 (UTC)

Deary is a good review article which I have acces to. He does not mention Rushton at all. He cites the Rushton & Ankney paper twice as a study sowing a correlation between head/brain size and IQ. Clearly WP:DUE suggests that we do not give Rushton more weight here than that.·ʍaunus·snunɐw· 21:10, 3 February 2012 (UTC)

• "Empirical research in this tradition began in the nineteenth century, when scholars such as Paul Broca and Francis Galton studied intellectual ability and achievement in relation to brain size. Brain size was mostly approximated by measures of head size, sometimes validated by post-mortem information. current data indicate that intelligence is correlated with head size (r ~0.20) and intracranial volume (r ~0.40). The clearest single body of evidence is that, in healthy people, total brain volume (measured using structural MRI) is moderately correlated with intelligence (r ~0.30–0.40)." No criticism of Rushton or his review. Acadēmica Orientālis (talk) 21:12, 3 February 2012 (UTC)

Again, all indications are that using Deary as a secondary source for article content seems to be entirely in line with sourcing policy and guidelines. Having located the source online: [6] it appears to be a robust secondary source which could be used as a basis for much of the article. The degree to which that review indicates the views of Rushton are relevant appears to be nil. You do earn bonus points for cutting off the last sentence of the excerpt: However, this does not mean that the basis of this correlation is understood. sigh aprock (talk) 22:16, 3 February 2012 (UTC)

The last sentence was not sourced to Rushton's paper and thus not an "excerpt" from it. Dreary's paper could be a source but I have seen no justification for excluding Rushton's review as a source. I have now shown that it is taken seriously. Acadēmica Orientālis (talk) 22:27, 3 February 2012 (UTC)

sigh: [7]. You don't need justification to exclude. You need justification to include. Your grasp of policy is a best failing you. aprock (talk) 22:40, 3 February 2012 (UTC)

A literature review is of course a perfectly legitimate source for Wikipedia. Acadēmica Orientālis (talk) 22:44, 3 February 2012 (UTC)

Dreary's review yes. Rushton's no.·ʍaunus·snunɐw· 23:07, 3 February 2012 (UTC)

Why? We have now established that it is used by other reviews which is what you asked for before. Acadēmica Orientālis (talk) 23:12, 3 February 2012 (UTC)

We have established that the appropriate weight to be given to Rushton's article is as a source in support of perhaps one sentence such as "studies have reported a positive correlation between brain and or head size and IQ (Rushton & Ankney)". Dreary does not more dedicate space than that to discuss Rushton in a general review of the field of neuroscience and intelligence and neither should we.·ʍaunus·snunɐw· 23:20, 3 February 2012 (UTC)

Dreary's review is called "The neuroscience of human intelligence differences" which is not identical with this article. For example, another subject covered by this article would be the evolution of brain size in relations to intelligence across different species which Rushton takes up in his other reviews. Acadēmica Orientālis (talk) 23:33, 3 February 2012 (UTC)

Also, if the material already covered in the IQ and other articles is removed there is not all that much left of Dreary's review so reducing Rushton's review to a single sentence is inappropriate. Acadēmica Orientālis (talk) 23:47, 3 February 2012 (UTC)

Removed material

Lots of material removed:

"Rushton and Jensen (2010) argue that the brain is metabolically demanding. In rats, cats, and dogs it uses about 5% of the body's energy. In primates, 10%. In humans, 20%. Larger brain are also expensive evolutionary since they take time to grow and requires larger bodies to produce and sustain them. So an increased brain size would not have evolved unless it gives great evolutionary advantages. They argue that brain size and brain-to-body mass ratio has been increasing for the last 575 million years. Mammals living 65 million years ago had substantially lower brain size than today. The hominid brain has tripled in size over the last 3 million years from Australopithecus to Homo erectus to modern humans. The claim that Neanderthals had average larger crania than anatomically modern humans has been falsified. Looking at brain to body size it was slightly smaller. They further argue that any decrease in average brain size over the past 35,000 years has been paralleled by a corresponding decrease in average body size suggesting no change in the ratio of brain to body size."

"Brain size is an import variable in Rushton's r-K theory which he described in his book Race, Evolution, and Behavior (1995). Rushton (2004) argued that the theory was supported by relationships between brain weight and several other variables among 234 mammalian species: longevity (r = .70), gestation time (.72), birth weight (.44), litter size (-.43), age at first mating (.63), duration of lactation (.62), body weight (.44), and body length (.54). The relationship remained after controlling for body weight and body length. Looking 21 primate species, brain size still correlated .80 to .90 with life span, length of gestation, age of weaning, age of eruption of first molar, age at complete dentition, age at sexual maturity, inter-birth interval, and body weight."

"Rushton and Ankney (2009) in a literature review write that in 28 samples using brain imaging techniques the mean brain size/g correlation was 0.40 (N = 1,389). In 59 samples using external head size measures it was 0.20 (N = 63,405). In 6 studies that corrected for that different IQ subtests measure g unequally well, the mean correlation was 0.63. Some studies have found the whole brain to be important for g while others have found the frontal lobes to be particularly important. Two studies founds correlations of 0.48 and 0.56 between brain size and the number of neurons in the cerebral cortex (based on counting in representative areas."

"In a study of the head growth of 633 term-born children from the Avon Longitudinal Study of Parents and Children cohort, it was shown that prenatal growth and growth during infancy were associated with subsequent IQ. The study’s conclusion was that the brain volume a child achieves by the age of 1 year helps determine later intelligence. Growth in brain volume after infancy may not compensate for poorer earlier growth."

Seems to be no good reason to remove all of this material. I propose adding it back. Acadēmica Orientālis (talk) 17:04, 3 February 2012 (UTC)

The reason for removing it was explained in the section above this one. Could you respond to that argument, please? Looie496 (talk) 17:30, 3 February 2012 (UTC)

Done. See above. Acadēmica Orientālis (talk) 17:36, 3 February 2012 (UTC)

Aprock's reverts

Aprock has reverted my edit, pointing to this talk page, which of course does not discuss my edit specifically.

I welcome his explanation of the revert of my edit, which used at least 5 different RSs, with suggestions and citations of still more possible RSs. The material is clearly relevant, it's well-formatted, the RSs are RSs, and the snozzberries are actually snozzberries. This would seem to pass WP:V, RS, etc.

At a guess from the above section, he dislikes Jensen. Which has never been a policy, and is, surprisingly enough, not even a guideline, and so completely irrelevant. But perhaps he has different reasons. --Gwern (contribs) 23:56 8 February 2012 (GMT)

I invite you to review the discussion above. The issue with any given source is ensuring that the appropriate WP:DUE weight is given. The best way to approach this is by using secondary sources as a basis for inclusion and coverage. As discussed above, the Deary source (introduced above by Acadēmica Orientālis) is a good example of such a secondary source. Note that the conclusions it makes about the research are contrary to the content you included, much of which is based on primary sources. With respect to Jensen, I'll note that this topic area is covered under WP:ARBR&I, where one of the primary findings of fact was: (iii) incessant over-emphasis on certain controversial sources. Jensen and Rushton are certainly controversial researchers in this topic area. aprock (talk) 00:07, 9 February 2012 (UTC)