Talk:Brain–body mass ratio

Diagram faulty

The diagram indicates a brain weight of about a ton for our species. I suspect the y-axis should be grams rather than kilograms (cf. Dicke & Roth, 2005). Unfortunately I don't have the means to change the figure atm Ben1982 (talk) 14:08, 13 April 2015 (UTC)

Also, the diagram seems to include only male humans "man", with "woman" not shown anywhere. Why are women not listed? If the data point labeled 'man' is supposed to represent both genders, surely it should be labeled 'human', right? T-bonham (talk) 21:26, 8 June 2016 (UTC)

Contradiction

The article contradicts itself. It says elephants among the lowest ratios among mammals and later it says they have among the highest. — Preceding unsigned comment added by 2001:4898:D8:1004:E111:8355:1972:8529 (talk) 19:20, 31 January 2013 (UTC)

This contradiction has been ignored for over 2 years. All mention of elephants must be removed unless a reliable source is found to substantiate one of the claims. — Preceding unsigned comment added by Perlscrypt (talk • contribs) 20:28, 3 April 2015 (UTC)

Stub and expand

Placed a stub and some basic articles to research. Plenty of room to expand this article with tables and graphs (see refs). :-) Kim Bruning 22:36, 13 Oct 2004 (UTC)

Splitting article

• As "Encephalisation Quotient" seems to be a far less common term have redirected (UK and US spellings) here. CheekyMonkey 23:01, 13 Oct 2004 (UTC)

Encephalisation Quotient is not the same as brain to body mass ratio, and the current arrangement is not acceptable. The page on Homo floresiensis, for example, now says that H. floresiensis has a similar brain to body mass ratio to H. erectus. This is false: the ratio is dissimilar (and generally considered irrelevant), it is the EQ that is similar, and relevant, and discussed with interest on the talk page.

I think we need a few short articles to define EQ, brain to body mass ratio, brain to spinal cord mass, and any other measures that are used. Then other articles can talk about e.g. the EQs of hominids and the reader will know what the author means. These pages can then reference this one, which should be retitled something like 'relative brain size' (or encephalization, but I think it's worth keeping the existing article with that name). This article can explain current thinking on how to compare brain size between species, and the significance of relative brain size. Securiger's comments below are a good start.

2 other notes:

• The Gould article linked suggests dividing brain mass by spinal cord mass, not subtracting. Was that what you mean, Ŭalabio?
• The "Cosmic Evolution" link has a plot of log(brain mass) vs. log(body mass), labelled "A plot of brain mass versus body mass". Since this is confusing, and the relevant parts of the text are rather vague, I favour removing this link, interesting though it is.

Townmouse 13:24, 5 Mar 2005 (UTC)

I agree. Clearly these are different concepts as we have separate tables and values displayed for each. EQ should be broken out into its own page. I separated the terms in the intro to avoid additional confusion. Niluop (talk) 10:56, 31 December 2010 (UTC)

I second the call to remove the incorrect identification between "encephalization quotient" and "brain to body mass ratio". Let's rename this article "encephalization quotient", and create a stub for "brain to body mass ratio" to caution against merging them again. Perhaps a more general article stub could be created to relate them, perhaps "inter-species scaling laws and intelligence". Bayle Shanks 06:25, 10 August 2007 (UTC)

I have now spilt the article into one on Brain-to-body mass ratio (this one) and one on Encephalization quotient. Bout will require cleanup. I have copied the discussion over to the EQ article, and deleted the parts that obviously only pertained to EQ from this discussion. Petter Bøckman (talk) 10:28, 5 January 2011 (UTC)

Brain-mass minus spinal-cord-mass versus encephalization quotient

The discovery that the brain-size increases with the surface-area of an animal is great and all, but I remember reading in an Issue of Natural History from the 1980s an article by Stephen Jay Gould where he noted encephalization quotient is good and all, but he observed that animals with small brains for the size of their bodies have brains with about the same size as their spinal cords. He wrote about this in "Bligh's Bounty." http://web.archive.org/web/20010709234346/http://yoyo.cc.monash.edu.au/~tzvi/GOULD.html He figures that all other things being equal (which they never all), the intelligence of an animal should be proportional to the absolute mass of the brain minus the mass of spinal cord. Ŭalabio 22:27, 2004 Dec 4 (UTC)

I have nothing much to say, other than that I agree with the previous posters that this article needs a major overhauling. The article seems to give a weak description of what EQ is not. It would be nice if we could give a short description of the history of EQ, the problems it was attempting to solve, its current acceptence in evolutionary biology, along with an accurate description of how it is found and what value it has.

I also think it would be appropriate to give a few lines as to why simple brain to body mass ratios fail, along with why brain size is not very valuable for determining intelligence.

Another poster knowing this article is bad, but without the motivation and confidence to fix it himself.

Furthermore, what can we say about people who lost half of their brains, and yet still perform just as well on IQ tests as people who have not lost half of their brains? 24.16.15.81 22:30, 16 July 2006 (UTC)

What we can say is that it is an urban legend, probably widely distributed by self-improvement promoters, although the origin of the story is uncertain (see, e.g. Snopes). People can receive severe head injuries or strokes and yet still (sometimes, eventually) recover many of their faculties (sometimes at a cost of losing others), but even ~30% loss causes crippling debility (see, e.g. Scans show dramatic brain cell loss in Alzheimer's). -- Securiger 07:29, 20 July 2006 (UTC)

Article Cleanup Co-Ordination Point

More important to me than "Brain-to-body-mass-ratio" would be the ratio of (neo?)cortex of the brain to medulla of the brain for various species. In particular, how would dolphins, shrews, and humans compare in this ratio for each of the three? 71.139.16.99 (talk) 04:04, 25 January 2011 (UTC)

Brain size in jumping spiders

Actually, jumping spiders have (by far) the highest brain/mass ratio of any invertebrates, and in maze-type intelligence tests, can outperform most primates.

Reprint of the 2006 article from New Scientist on jumping spider intelligence:

http://www.newscientist.com/article/mg19025531.400-smarter-than-the-average-bug.html

full article can be read in the cache here: http://74.125.47.132/search?q=cache:VdTETgfIyw0J:www.freerepublic.com/focus/f-chat/1640513/posts+Portia+labiata:+new+scientist&hl=en&ct=clnk&cd=1&gl=us

This is despite their very tiny brain in overall mass!

In fact, I think they have the highest brain/mass ratio of any animal. See the anatomy figure in this article: http://tolweb.org/accessory/Jumping_Spider_Vision?acc_id=1946

Peters' elephantnose fish

I think that Peters' elephantnose fish should be included in this article. They have a higher brain-to-body mass ratio than humans as well, and are apparently fairly intelligent. Also they can do really neat metal detecting things in total darkness! Here's a blog entry about them:

http://scienceblogs.com/zooillogix/2007/08/hilariouslooking_fish_uses_chi.php Gary 00:33, 23 August 2007 (UTC)

According to Göran E. Nilsson's paper Brain And Body Oxygen Requirements Of Gnathonemus Petersii, A Fish With An Exceptionally Large Brain (1996) its brain-to-body mass ratio is 0.0309±0.0034 ≈ 1/34 —Preceding unsigned comment added by 84.189.3.25 (talk) 01:30, 9 January 2011 (UTC)

Agreed. I have added the elephantfish to the main page. — Preceding unsigned comment added by Xiphoidp (talk • contribs) 21:11, 7 June 2011 (UTC)

The main problem seems to be that the matter is far from forgone conclusion

The various "citation needed" are irrelevant - I have found plenty. However, the criticism offered here by [1] and others is viable. The problem is not lack of sources, but lack of research.

I think the best course of action is to state clearly that the issue is heavily criticized and to remove the numerous "citation needed" marks.

Zarnivop (talk) 10:26, 15 September 2008 (UTC)

Roughly speaking

"Roughly speaking, the larger an organism is, the more brain weight is required for basic survival tasks, such as breathing, thermoregulation, senses, motor skill, etc"

How roughly? Whom are speaking? Can anyone find any explanation why more brain weight is required for breathing of larger animal? Same goes for motor skills. If something, larger animal breathes, thermoregulates, walks, and so on at lower rate (in actions per second), thus requiring less computation for doing this. That is just basic logic. If that logic is invalid and more brain weight is indeed 'required', that would be rather extraordinary and outstanding - and would require some research which explains why more brain mass is required for doing less computationally intensive task. —Preceding unsigned comment added by 78.56.104.90 (talk) 13:05, 8 August 2009 (UTC)

I don't think this is entirely true. For mammals, the general rule of thumb is the larger the body, the larger the brain, but the larger the body the smaller the relative size. To the degree that we can draw any conclusion from this, then it appears that "basic survival tasks" (breating, heartbeat, thermoregulation) is rather idependent of body size in mammals. Petter Bøckman (talk) 08:49, 3 December 2010 (UTC)

"However, large animals need more neurons to represent their bodies and control specific muscles, so that relative rather than absolute brain size makes for a ranking of animals that coincide better with observed complexity of behaviour" Doesn't that contradict the walnut sized brains of some of the largest animals ever to have lived? — Preceding unsigned comment added by 63.66.112.5 (talk) 13:30, 9 September 2014 (UTC)

Criticism

The section on Criticism argues without having a good argument. It is only fluff at this point. It should be removed or completely re-written.

Recent research indicates that whole brain size is a better measure of cognitive abilities than EQ for primates at least.[13]

"While Stegosaurus was undoubtedly a simple and unintelligent animal, this fact undermines the idea on which EQ is based - that a larger animal requires a larger brain to look after its basic functions." This is not clear at all.

"If Stegosaurus could survive with this tiny brain, this can only mean that any animal with anything bigger must be using it for non-essential abilities." This is not necessarily true; humans evolved bigger brains so they could manipulate their environment; why couldn't stegosaurs have done the same with bigger brains? Answering, "No, because they were stegosaurs" would be a circular argument.

"Some of these abilities may be sensory and/or physical, and some may be intellectual. The actual intelligence of an animal therefore depends on the size of the brain and the proportion of the brain that is used for intellectual abilities, rather than advanced sensory or physical skills." This is similar to Larmarkianism. The quote basically says the animals get intelligent is by using their intelligence.

"Critics[who?] point out that EQ gives only a very rough estimate of these proportions." This sentence should either be supported or removed. 173.217.167.73 (talk) 18:02, 14 December 2010 (UTC)

I agree with the above (unsigned) criticisms. I would go farther and say that many sentences in the article "should either be supported or removed." The article appears to be no more than a rough draft, which may be used as a skeleton for other editors to build a real article out of, so it may warrant an "under construction" header before it's unsupported claims start getting cited by students unaware of how Wikipedia works. I don't want to put the header at the top since I lack the knowledge to build it.HkFnsNGA (talk) 19:46, 24 December 2010 (UTC)

A Bad Source?

The source from the table links to [1] serendip.brynmawr.edu. This is turn mentions another source: Kuhlenbeck, 735.

I have been looking for "Kulhenbeck, 735" on Google and all I get are different websites listing the same table. A quick look on Google Scholar using various search terms ("Kulhenbeck body-to-brain ratio" etc.) is of little help. The only data I've been able to find was on another page from serendip:

http://serendip.brynmawr.edu/~pgrobste/kinser/kinser2/How1.html

Even they suggest Kuhlenbeck may be wrong, even though everyone sources his data from their website. Long story short - this sounds like a mistake that has been repeated so often people think it's the truth. Should we remove it?

--Lyrical Jesse James (talk) 09:41, 10 September 2011 (UTC)

Improved precision in the language needed

I feel the article needs a big tidy-up. For example, it mixes mass, weight and size in a confusing manner. The table of "Simple brain-to body ratio" doesn't say which measurement is used and omits several of the species mentioned in the text (dolphins, shrews, etc). Is anyone managing the page? Thanks, --p.r.newman (talk) 12:58, 15 March 2013 (UTC)

The article suffers from being what was left after Encephalization quotient as split off and made into a new article. The remaining text has largely been ignored I think. You are most wellcome to tidy it up. I'll try to help if there's something that's unclear or badly sourced. Petter Bøckman (talk) 10:41, 16 March 2013 (UTC)

Are we really willing to describe the very vague "small ants" or "small birds" as 'species' in the table? Even terms like 'mouse' are far more generic than specific. Very poor science. Kevin McE (talk) 18:12, 8 February 2014 (UTC)

Discussion that relates to this page

Please see Wikipedia talk:WikiProject Neuroscience#Brain size and Human brain size. Thanks. --Tryptofish (talk) 23:40, 6 September 2014 (UTC)

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Errors in the Brain-body mass ratio diagram

The first diagram should probably be replaced. Perhaps by the one from http://brainmuseum.org/ (http://neurosciencelibrary.org/Evolution/paleo/brnBodWt.html)

Here is what makes me think the diagram should be replaced:

1. Both Mouse and Shrew appear twice.
2. The shrew is later said to have among the largest brain-to-body mass ratios. Then it should be above the trend line in the diagram. It isn't.
3. Bat is below the trend line while in the diagram I linked to it is far above the trend line.
4. At the time of writing there are two additional complaints about the diagram on this talk page.

It could be that the statement of shrews having such a large brain-to-body mass ratio is simply wrong. It says that they are relatively closely related to moles (Shrews) but in the diagram I linked to the mole is below the trend line. (Or the diagram I linked to is incorrect... Or the 'relatively close relationship' doesn't matter as much...)