Talk:Brain size/Archive 1

Wrong interpretation of information about woman and man grey matter ratios from the articles used as reference
"When individual cortical lobar volumes were compared, the right to left asymmetry held in all regions except the parietal, where the sides were not significantly different in size. Interestingly, female left parietal cortical volume was the only measure not significantly smaller than the male counterpart, and was larger as a proportion of left cerebral hemisphere than in males. Past studies have suggested proportionately greater grey matter volume in females, with the suggestion that greater total brain volume in males correspond to increased white matter volume, implying perhaps the same computational capacity, with preserved amounts of grey matter, but more lengthy intracranial connections.[4], [9] and [31] It is of interest that Gur et al. found the absolute volume of grey matter was also lower in females, a finding that we have replicated."


 * Carne et al. Cerebral cortex: an MRI-based study of volume and variance with age and sex. J Clin Neurosci (2006) vol. 13 (1) pp. 60-72

"In adult men and women, global grey matter decreases linearly with age with a steeper decline in men (24; 38), a finding that has been confirmed postmortem (39). The reasons for these differences are not clear but may be related to the female sex steroids. There have been no studies evaluating the female sex steroids estrogen and progesterone and their receptor systems in the living human brain because the tools are currently unavailable."


 * Cosgrove et al. Evolving knowledge of sex differences in brain structure, function, and chemistry. Biological Psychiatry (2007) vol. 62 (8) pp. 847-55 —Preceding unsigned comment added by 81.60.184.174 (talk) 17:38, 13 December 2010 (UTC)


 * Gender disparity percentages in grey and white matter is unsupported by Taki et al (2011)


 * Citation: Taki Y, Thyreau B, Kinomura S, Sato K, Goto R, et al. (2011) Correlations among Brain Gray Matter Volumes, Age, Gender, and Hemisphere in Healthy Individuals. PLoS ONE 6(7): e22734. doi:10.1371/journal.pone.0022734


 * --Vitki1963 — Preceding unsigned comment added by Vitki1963 (talk • contribs) 07:38, 10 August 2013 (UTC)

Brains shrinking
Please see these links here, evidence that human brain size is shrinking. There should be a section about this on the article.


 * Link 1
 * Link 2
 * Link 3
 * Link 4
 * Link 5
 * Link 6

Chemistryfan (talk) 16:50, 18 September 2011 (UTC)

Human Encephalization quotient
Homo sapiens quotient is claimed to be 4.6 whereas on encephalization quotient it is listed as 7.4-7.8. I cannot access the Aiello and Wheeler paper to verify their estimate and the larger quotient number, on its own page, is unreferenced. Can someone with journal access please resolve this. I have placed a similar request on encephalization quotient. FloreatAntiquaDomus 10:27, 13 April 2012 (UTC) — Preceding unsigned comment added by FloreatAntiquaDomus (talk • contribs)

Merge with Cranial capacity
Articles cover the same topic, but "brain size" is more general. jonkerz ♠talk 05:48, 17 June 2013 (UTC)
 * I would support that. Looie496 (talk) 14:38, 17 June 2013 (UTC)
 * I am in favor of it, cranial capacity can be made a redirect to brain size....

AmRit GhiMire &#39;Ranjit&#39; (talk) 13:51, 9 August 2013 (UTC)
 * I have completed this merge. --LT910001 (talk) 08:53, 21 February 2014 (UTC)

Brain Size and Intelligence
96.255.146.176 cites the source http://www.bbc.co.uk/news/science-environment-14279729 and added the follow text to the "Intelligence" section:

"Researchers have also found strong evidence that northern populations have larger visual processing area which makes up the population differences in brain size rather than intelligence and that the visual processing enlargement was possibly due to the cold dark winters(similar to the Neanderthals)."

There are several problems from 96.255.146.176's edit. Pearce is referring to her own study which is:

Pearce, Eiluned, and Robin Dunbar. "Latitudinal variation in light levels drives human visual system size." Biology letters 8.1 (2012): 90-93.

This is a study regarding the correlation of human orbital volume to latitude. It is not a study on intelligence and there is absolutely no mention of intelligence in Pearce's study at all. Pearce, when discussing her own study in the BBC link, mentions that bigger brains in populations of higher latitude, doesn't mean that they are necessarily smarter. This is very different from 96.255.146.176's text which claims that there is "strong evidence" that visual processing area rather than intelligence causes population differences in brain size. The source doesn't make a "strong evidence" claim about anything. But beyond that point, Pearce's study had absolutely nothing to do with intelligence, the quote by Pearce in BBC is entirely speculative on her part with absolutely no peer review support, and there is no cited source to support this speculative commentary by Pearce.

With problems relating to WP:PRIMARY, WP:SYNTH, WP:V, WP:NEWSORG, I removed the text in question. BlackHades (talk) 11:00, 22 September 2013 (UTC)


 * What are the reliable secondary sources that support current article text? -- WeijiBaikeBianji (talk, how I edit) 12:51, 22 September 2013 (UTC)
 * For which line specifically? BlackHades (talk) 20:40, 22 September 2013 (UTC)

I decided to insert this in cranial capacity since the two articles might be merged and more importantly, it relates more to that then this one. I gave a second source that describes the differences among latitude populations in visual cortices and how that potentially explains why humans living at higher latitudes are selected for bigger brains( specifically the visual cortex) to cope with poorer lighting conditions in the colder climates. — Preceding unsigned comment added by 96.255.146.176 (talk) 03:31, 23 September 2013 (UTC)

Can someone fill in sources for the implied controversy between brain size and functioning, as I have found some neurology papers that have such link, and am not familiar with the controversy? User:Puuska —Preceding undated comment added 22:40, 8 February 2014 (UTC)


 * Intelligence Citations bibliography -- WeijiBaikeBianji (talk, how I edit) 04:03, 9 February 2014 (UTC)

Intelligence citations bibliography for updating this and other articles
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) 21:06, 24 April 2014 (UTC)

Rewriting the article
I read through the whole article about brain size today for the third time in like three weeks. It is not a specifically good article and alot of it is without citations, like the evolution part that had no sources at all(edit: I have slashed the unsources parts). It is furthermore not a very long article. So may I recommend we Rewrite most of it. (I am already doing it)... And add sources to everything (especially the currently unsource brain size of early hominids)

Just anything that can improve the current situation. :) Sincerely MicroMacro!! MicroMacroMania (talk) 09:38, 5 September 2014 (UTC)

Proper sourcing for this article
I see that there are a lot of edits going on here, but some of them are in disregard of the tag on the article suggesting that we all look for more reliable sources, especially secondary sources, for further edits. An article about brain size (not just for human beings, but for all living things that have brains) is inherently about a scientific topic and especially for the parts of the article on human brains an article about a medical topic. So the content guidelines on medically reliable sources would be the best guidelines to sourcing to apply to further article edits. It will not do, by long established Wikipedia policies and guidelines, to source statements in article text here to primary research articles published in scientific journal articles, as many of the findings in such articles are never replicated and many of the statements in such articles are often made in ignorance (willful or inadvertent) of much of the prior literature on the topic.

Good sources on the subtopic of human brain size include









The consensus of these sources should be reflected in article text after further editing. -- WeijiBaikeBianji (talk, how I edit) 13:48, 5 September 2014 (UTC)

Well it is primarily me, who is going cracy with rewriting the article and adding sources to the formerly unsources parts (I wrote a new evolution part!!)... Anyway I will read through all those articles through and see what I can do in that direction... Thx you! :) MicroMacroMania (talk) 13:55, 5 September 2014 (UTC)


 * There are a couple of sources that are better regarding brain size, there are at least two review articles specifically about this topic, one is by McDaniels 2005 and I forget the other one. Another one is Ian Dearys 2011 review of "intelligence" which actually states it as a by now wellestablished fact that bigger brained people tend to have higher IQ. I think I probably gave too much weight to Nisbett, FLynn et al, given that that paper is not specifically about Brain size. Another good source is the book "human biological variation" by Mielke, Koenigsberg and Relethford. They state clearly that headsize is correlated with climate and that brain size follows head size.User:Maunus ·ʍaunus·snunɐw· 17:46, 5 September 2014 (UTC)

Hey I am reading them all through today, and trying to write something tomorrow. But what about splitting up the article? The part about humans, does it not fit better into its own article "human brain size".. Cranial Capacity could use its own page too and the rest about animals in to "Brain-to-body mass ratio"? MicroMacroMania (talk) 07:29, 6 September 2014 (UTC)

Okay I am just going to do it... No one responded.. Reverse me if you totally disagree.MicroMacroMania (talk) 14:51, 6 September 2014 (UTC)
 * I think you should move that split content back, then we can discuss whether it makes sense to do. You cant expect to get responses from other editors within 12 hrs of posting.User:Maunus ·ʍaunus·snunɐw· 04:00, 7 September 2014 (UTC)

Ups... Seems like people have made some edits to what I have changeds... Okay I reverse or what??? I can just move cranial capacity and that about animals back here and keep the new good edits.. Or what? MicroMacroMania (talk) 06:31, 7 September 2014 (UTC)

Okay I have made quite some edits.. Seem to get far with this. Most about non human things are moved to seperate areas where they fit better. I also made some edits across the board to the different places. Anyway I asked on the article "human brain" if this article can be merged with that under a new heading called "size"... Agree or disagree?MicroMacroMania (talk) 18:36, 6 September 2014 (UTC)
 * I wouldnt have a problem with the merger to a subsection of "human brain". I have not yet seen the rest of your edits.User:Maunus ·ʍaunus·snunɐw· 04:00, 7 September 2014 (UTC)

Okay I got quite alot of hateful messages.. I reversed the edits.. Lets have a debate about what to do. :) Anyway the problem for is that the topic about brain size is not interest as such, of course brain size in animals increase with body size. Therefore animal brain size is much better covered under the area of brain size to body size ratio article. Furthermore the area for "brain size" is GIANT topic that have to be divided up. So cranial capacity can have a separate article.

The text about brain size for humans seems to fit into the area of "human brain", as that variation actually have some importance for for discussion about the human brain. MicroMacroMania (talk) 07:35, 7 September 2014 (UTC)
 * Brain size is not such a huge toic that it needs to be divided up. There is not a huge literature on this topic, and most of what is there are studies of encephalization in primate evolution. This regards specifically the cephalization index, since that is what is interesting in regards to evolution. Most studies that relate brain size to intelligence in humans is outdated studies from the anthropometric phase of pseudoscientific physical anthropology. There is a small body of studies on human brain size and intelligence. Honestly I think you need to slow down a lot, it doesn't seem as if you have a full overview of this field at this point. Slow down. Read more. Discuss more. Otherwise things will get unwieldy. User:Maunus ·ʍaunus·snunɐw· 19:21, 7 September 2014 (UTC)

Please see
There is a related discussion at Wikipedia talk:WikiProject Neuroscience. --Tryptofish (talk) 20:06, 8 September 2014 (UTC)