Talk:Brain size

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Please see[edit]

There is a related discussion at Wikipedia talk:WikiProject Neuroscience#Brain size and Human brain size. --Tryptofish (talk) 20:05, 8 September 2014 (UTC)

This article could be improved in the evolution of brain size/ development section by: 1)drawing upon information such as genetics or gene expression that factors on brain size such as the gene ASPM. 2) talk about brain formation and development from birth to adulthood and how size is affected by many characteristics/ life choices (i.e. alcohol which hinders gene expression/ development) 3) elaborate on why or provide information as to how the brain has decreased in size over time form the neanderthal relatives that are spoken of in the evolution section.

information on these topics can be found

Dolven.1 (talk) 00:13, 1 October 2014 (UTC)Grant

The meaning of brain size in races[edit]

Might it be a coincidence that races with bigger brains have weaker bodies and gracile features, while races with robust traits have smaller brains? There seems to be a correlation here, with Australian Aboriginals having the smallest brain capacity while also having the largest, most powerful jaws and strongest body structures of all races. Closest to them in that respect are the Negroids, who've got the second strongest jaws, second thickest bones, second strongest muscles, and the second smallest brain capacity. Compare that to the Mongoloid's and Caucasoid's cranial capacity relative to body size, bone structure and thickness, muscle size, and history of complex civilizations, rich culture, and IQ scores.

These facts are hard to ignore and troubling given how society can treat everyone the same based on the assumption that all people are equal. Scientists would probably never delve into this because society would have to be reformed if racial disparities in intelligence are discovered. It is already confirmed that brain size in proportion to body size contributes to intelligence in humans, but we'd rather live a lie for an ideal world than to seek truth. — Preceding unsigned comment added by (talk) 01:52, 22 December 2014 (UTC)

Gah...User:Maunus ·ʍaunus·snunɐw· 01:59, 22 December 2014 (UTC)

An interesting picture[edit]

I know we cant add it to the article, but still interesting certainly.MicroMacroMania (talk) 11:23, 27 September 2014 (UTC)

colder climate intelligence theory[edit]

A bunch of of guys have argued for that colder climates have caused natural selection for higher intelligence through bigger brain size.. Is it worth adding? Arthur Jensen, Richard Lynn and Phillip Rushton all argued for it. But what is the consensus between scientist on the topic? MicroMacroMania (talk) 19:18, 2 October 2014 (UTC)

Scientific consensus is that that is nonsense. And dedicating a third of the biogeographical variation paragraph to this view is a clear example of undue weight.User:Maunus ·ʍaunus·snunɐw· 19:36, 2 October 2014 (UTC)

Whats the basis for this thought process? where is the science that backs up such a thought?Dolven.1 (talk) 00:32, 16 October 2014 (UTC)Grant

race differences in intelligence, Race, Evolution, and Behavior or and a troublesome inheritanceParanoidLemmings (talk) 19:20, 17 October 2014 (UTC)

Agreed that any interpretation of data sets correlating brain size & race is fringe. AgentOrangeTabby (talk) 22:06, 7 November 2014 (UTC)

Sources for decreasing brain size[edit]

The cited source [6] for the decrease in brain size is not a scientfic source and the article contains many flaws. I delved a bit in to the hypothesis of brain shrinkage in H. sapiens and it seems there is just one finding of one Cro-Magnon skull which has a bigger brain size than average modern H. sapiens. But this one finding says nothing about the average Cro-Magnon brain and is definitely not enough to conclude that he had a larger brain compared to modern H. sapiens if you consider the variability in brain size of modern H. sapiens.

Additionally there seems to be no scientific literature that modern H. sapiens has a smaller brain, at least I couldn't find any, and therefore, if no other sources can be presented I would like to remove that passage because wikipedia is not here to spread myths of the popular press.LuxMaryn (talk) 16:08, 21 January 2015 (UTC)

Okay, that makes sense -- but I assume you won't take out the fact that the brain of modern man is smaller than the neanderthal brain? Looie496 (talk) 19:36, 21 January 2015 (UTC)

No, I wouldn't take that out. Although I haven't checked it yet. If there are any anthropologists here be welcome to object, but as long as this is not the case I suggest it is better to leave the hypothesis of decreasing brain size in H. sapiens out than to spread a putative myth. LuxMaryn (talk) 22:11, 21 January 2015 (UTC)

Some addition: No easy topic with a lot of inconsistent sources. For example the wiki Cro-Magnon 1 article cites a source [2] which states that the neanderthal cranial cavity is smaller, giving 1,100-1,600 cm3 for Neanderthals and 1,200-1,700 cm3 for modern humans. But I don't think this source is really trustworthy. I could also find out that there is also a female Cro-Magnon skull, but couldn't find any data about the cranial cavity about this one. But I finally found some sources about brain shrinkage in humans (the shocking truth and some backup for average modern H. sapiens brain size LuxMaryn (talk) 00:32, 22 January 2015 (UTC)

I have now added some sources and made some minor changes to the article. I changed the size of the neanderthal from 1500 cc (which was without source) to 1600 cc (with source from the wiki neanderthal article) to be consistent with the hypothesis that neanderthals had the biggest brain in hominid evolution. But a better source for that too would be nice. I think a major confusing also stems from the lack of differentiation between brain size and cranial capacity of the skull, which is probably still not well resolved in the article. LuxMaryn (talk) 01:19, 22 January 2015 (UTC)

While you guys are at it, what do you think of the statement:"Men have 10% bigger brains than women." I almost removed it. I think it shows more bias than is acceptable. Can we also say men are X% taller or X% faster than women? Brain size roughly correlates with organism mass, and the average man is larger than the average woman. But group averages aren't properties possessed by individuals. The error is imputing to the group a property of the average of the group. Next, we'll be talking about families having 2.1 children. The reason that I did not unilaterally remove it is because you guys are currently active on this page, rather than because I lack the assertiveness/arrogance/presumption. The statistical averages are provided, so the statement isn't necessary. Its a sound bite. Stating that "men" have brains larger than "women" is NOT the same as saying men's average brain is larger than the average women's brain. Its more likely, imho, to be misused than it is likely to inform. But, since you guys are active and I'm (as usual) shooting from the peanut gallery, I will defer to you. My point is many here will infer from men have the logic that if men have X, and I am a man, then I have X (or I am a woman then I have X-10%...). I also have a problem with the statistics, since the sample is admittedly too small and highly Eurocentric. Most men are NOT "of European descent", and the difference between body masses is, to some extent, different depending on ethnic origin. Theres also problems with what is meant by "men" and "women" is that based on genitalia? skeletal structure? hormone levels? chromosomes? I've read that male human brains have significantly more neurons than females at age 20 but that is reversed by age 50-55, since men lose brain cells at a higher rate. This also makes the "average" rather meaningless, I think.Abitslow (talk) 00:50, 23 January 2015 (UTC)

I will remove the 10% thing, if I find something better way of explaining it, will we will put that in :)ParanoidLemmings (talk) 14:01, 27 January 2015 (UTC)

"Racial" differences in Brain size[edit]

An editor wants to include a list of bare figures of supposed average brain sizes for different populations. It is selected to as to give the appearance that there are systematic differences between continental populations. This is WP:OR and WP:SYNTH and should not be included in the article. The only study that actually gives a comparison between different geographic populations is Beals et al, and it gives a geographic, not racial description of the differences in size. The representation of it as "racial/ethnic" groups therefore misrepresents the study, and we cannot assume that figures across sytudies are comparable, nor can we represent them side by side.User:Maunus ·ʍaunus·snunɐw· 02:53, 27 January 2015 (UTC)

A simple listing of the different sizes, when the citations are valid, can hardly be said to constitute WP:OR or WP:SYNTH, doesn't seem to be any reason to remove. User:Firefox 03:09, 27 January 2015 (UTC)
I beg to differ. The studies of average sizes could have been picked differently to produce a different ordering of size. For example brain size is highly variable within Africa, but a single figure is given here.User:Maunus ·ʍaunus·snunɐw· 03:12, 27 January 2015 (UTC)
I assume they're averages for those regions as yes individuals will have variation of course (and such could be stated). If the literature used to cite the 'Modern Humans, Africans' value is available online or from another source it should be double-checked. The sources cited for the other groups do seem to check out and appear reputable however, so simple deletion of the entire section as seems to have occurred in a small edit war seems unjustifiable. User:Firefox 03:22, 27 January 2015 (UTC)
But why take the highly specific "scandinavians" (based on how many samples?) from one source, and then an average of the entire African continent (based on how many samples?). Deletion is entirely jutifiable given that this has direct bearings on the representation of the controversial question racial differences in intelligence. We cannot allow even a modest amount of SYNTH or cherrypicking in this topic area.User:Maunus ·ʍaunus·snunɐw· 04:02, 27 January 2015 (UTC)

I agree with Maunus, brain sizes in humans vary alot within given continents, so the list dont seem to do it. Besides the part about biogeographic variation explain what is needed about why brain sizes in humans vary - depending on bergmanns rule.ParanoidLemmings (talk) 14:00, 27 January 2015 (UTC)

Maunus, ParanoidLemmings it seems this user is back re-inserting the information. As you state there are a number of problems with this. Firstly the studies are not reliable biomedical sources (WP:MEDRS). I am very unhappy that a group of 8 Aboriginal Australians and 64 Koreans are used to generalise for the whole race, which as you state is a massive generalisation. Secondly if these sources are not reliable then we shouldn't include it, as at least in my part of the word this is laden with racist connotations. --Tom (LT) (talk) 22:42, 3 April 2015 (UTC)
I agree, and I have reverted a chunk back to an earlier version.·maunus · snunɐɯ· 22:46, 3 April 2015 (UTC)

Deleting the map over brain size[edit]

Some random IP adress removed the map, I undid it, but I think it might be a good idea to delete as it is an old map. Who agree to keep the map deleted?ParanoidLemmings (talk) 18:05, 7 March 2015 (UTC)

I think its potential to mislead is probably greater than its potential to inform. It also may be giving undue weight to that particular fairly dated study. I don't think we need it.·maunus · snunɐɯ· 01:28, 8 March 2015 (UTC)

Well I am just gonna let it stay removed then. ParanoidLemmings (talk) 09:00, 8 March 2015 (UTC)

Explanation of reversion[edit]

I am about to revert an edit made today by Constantinaki (talk · contribs), and would like to explain why first. The reasons for reverting are (1) there is no evidence that the hypothesis has gained any substantial attention in the field -- Google Scholar shows zero citations for the referenced paper, and I'm not aware of any press coverage; (2) Wikipedia articles must not be used for the purpose of advertising one's own work. Looie496 (talk) 11:48, 30 September 2015 (UTC)

Reverted edit by CorinaLogan[edit]

Yesterday CorinaLogan (talk · contribs) made an edit saying, However, this method of measuring cranial capacity must be validated in each species to know whether it is an accurate representation of the braincase( ref: Logan & Clutton-Brock (2013). "Validating methods for estimating endocranial volume in individual red deer (Cervus elaphus)" (PDF). Behavioural Processes. 92: 143–146. doi:10.1016/j.beproc.2012.10.015. ), ref:Logan & Palmstrom (2015). "Can endocranial volume be estimated accurately from external skull measurements in great-tailed grackles (Quiscalus mexicanus)?". PeerJ. 3: e1000. doi:10.7717/peerj.1000. ). The edit was reverted by Melcous (talk · contribs) with an edit summary saying, rv coi links. In my judgement this is an important point and the reference is reasonable to support it -- it would be better to have a secondary source, but it is possible that none exists. I would like to put the passage back, though perhaps with only one of the two listed refs. Any thoughts? Looie496 (talk) 13:18, 9 November 2015 (UTC)

Hi, I have no problem with that. It would have been preferable for CorinaLogan (talk · contribs) to suggest the edit here on the talk page first to avoid the conflict of interest issues. If you or other editors with expertise in the area think the content and references are helpful then go for it Melcous (talk) 03:13, 10 November 2015 (UTC)

Comment from CorinaLogan[edit]

Hello, Sorry about the confusion. I just joined Wikipedia a couple of days ago and started editing the great-tailed grackle page, but it didn't have an editor so it was a different process. I was treating the brain size page like the grackle page, but when a page has an editor it seems like it is a different process and I didn't realize there was a format for suggesting a change without making it directly myself. Regarding other relevant literature, there isn't any that has validated within species bead vs CT scan vs linear measurements using the prediction analysis (which measures the accuracy of the correlation rather than just showing a correlation) that I used in Logan & Palmstrom (2015), so if you were to choose one reference, I would go with that one. My best, CorinaLogan (talk) 08:14, 10 November 2015 (UTC)

It isn't generally a problem for you to make changes yourself. Unfortunately there have been many cases of academic authors trying to use Wikipedia to advertise their work, by inserting references to it where they don't belong -- as a result self-references tend to be viewed suspiciously. But there are, of course, cases where a self-reference is actually the best reference to support a statement that properly belongs in the article. Looie496 (talk) 12:53, 10 November 2015 (UTC)

Brain weight[edit]

The adult human brain weighs on average less than 1.5 kg. For example in a study, the weigth of the brain of controls were (mean and (SD grams)): in Men <50y = 1427g (138), from 51 – 60y = 1441g (147), 61 – 70y = 1357g (129), 71 – 80y = 1347g (126), >80y = 1276g (138). In Women <50y = 1304g (143), from 51 – 60y = 1250g (95), 61 – 70y = 1258g (120), 71 – 80y = 1204g (132), >80y = 1124g (116) � — Preceding unsigned comment added by Gcastellanos (talkcontribs) 02:35, 17 December 2016 (UTC)