Reply
 
Thread Tools Display Modes
  #1  
Old 06-23-2016, 11:04 AM
jtur88 jtur88 is offline
Guest
 
Join Date: Aug 2011
Location: Cebu, Philippines
Posts: 13,305
Why are breasts so variable in size?

What could account for the fact that human female breasts vary so widely in size, within a range that is considered normal? Everybody knows women whose breast size, from one individual to another, varies within a range of about 10:1 ratio, and are considered normal size.

Is there any other part of the human body that can vary that much in size from one healthy person to another? Or, for that matter, in any other species of animal?
  #2  
Old 06-23-2016, 12:11 PM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 14,963
Why are breasts so variable in size?

The powers than be love men?
  #3  
Old 06-23-2016, 12:45 PM
Colibri Colibri is online now
SD Curator of Critters
Moderator
 
Join Date: Oct 2000
Location: Panama
Posts: 37,543
Quote:
Originally Posted by beowulff View Post
Why are breasts so variable in size?

The powers than be love men?
Moderator Note

Let's avoid joke answers in GQ until some factual answers are posted. Nor do I want to see this become a thread about opinions about what size breasts you like. You're welcome to start another thread in another forum about size preferences (or if you must) titty jokes.

Colibri
General Questions Moderator
  #4  
Old 06-23-2016, 01:03 PM
Exapno Mapcase Exapno Mapcase is offline
Charter Member
 
Join Date: Mar 2002
Location: NY but not NYC
Posts: 29,367
There is a book on every subject, which means I own a book on every subject. Specifically, I own Breasts: A Natural and Unnatural History by Florence Williams. And this exact question is asked.

But never answered. The question is raised during a look at why humans developed larger breasts than other primates. That answer appears to be for fat storage. She never gets around to a direct discussion of variability, even in the chapters devoted to breast augmentation.

I might have missed an answer, since I wasn't reading for that, so you might want to find the book for yourself. It's more breezy journalism than academic in tone and is a fast and fascinating read.
  #5  
Old 06-23-2016, 01:09 PM
Asuka Asuka is offline
Guest
 
Join Date: Feb 2016
Posts: 419
Quote:
Originally Posted by Exapno Mapcase View Post
There is a book on every subject, which means I own a book on every subject. Specifically, I own Breasts: A Natural and Unnatural History by Florence Williams. And this exact question is asked.

But never answered. The question is raised during a look at why humans developed larger breasts than other primates. That answer appears to be for fat storage. She never gets around to a direct discussion of variability, even in the chapters devoted to breast augmentation.

I might have missed an answer, since I wasn't reading for that, so you might want to find the book for yourself. It's more breezy journalism than academic in tone and is a fast and fascinating read.
Yeah I picked up the book on an audible sale and while enjoyable the book didn't really answer any of the questions I had about breasts in the first place.
  #6  
Old 06-23-2016, 01:19 PM
Asuka Asuka is offline
Guest
 
Join Date: Feb 2016
Posts: 419
This is all my best guess going from books I read and has nothing backing it but my memory, but the idea being that in the very beginnings of humanity breasts were uniform in size but as civilization advanced and different cultures took different ideas about breasts they became things for sexual arousal and as a result changed size accordingly. Some cultures preferred large breasts as an indicator of good health so in those societies the busty women were the ones with the most off-spring and their off-spring wound up passing the busty genes as well. In other societies the opposite happened, smaller breasts were valued as large breasts were believed to indicate women in poor health and those genes were spread. Though trade and mass migrations have made this less obvious in modern communities you can still see what societies valued large breasts based on their average cup size once you control for obesity and other stats. Russian women tend to be the bustiest in the world on average because in their society very large breasts were the most sexually attractive feature to men.
  #7  
Old 06-23-2016, 01:19 PM
robby robby is offline
Charter Member
 
Join Date: Dec 2000
Location: Connecticut, USA
Posts: 5,113
My WAG: women's breasts are a secondary sex chacteristic that, for many men, heavily influences their attractiveness. This in turn affects whether or not women with certain breast chacteristics are likely to reproduce and pass the relevant genes on to their progeny.

All men do not have the same preferences for a given breast size (which is also affected by social factors, I expect), so it is not surprising that a wide variation of breast sizes might arise.
  #8  
Old 06-23-2016, 01:30 PM
TroutMan TroutMan is offline
Guest
 
Join Date: Sep 2008
Location: Portland, OR
Posts: 3,687
Googling led me to The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature by Geoffrey Miller. I read only a few pertinent pages from here, so I can't evaluate if there is any scientific backing for this or if the guy is a complete quack.

Miller suggests it is due to men selecting partners based on different indicators of fitness. One fitness indicator might be larger breasts, indicating adequate nutrition. Another might be a tall and muscular build, which is not necessarily correlated with breast size. Fitness indicators would be genetically prioritized under conditions of "scarce bodily resources." In his view, this explains why "not all women have very large breasts - many women may be genetically programmed to prioritize other indicators of physical and mental fitness."

I'm not totally sold on this.
  #9  
Old 06-23-2016, 01:58 PM
Ignotus Ignotus is offline
Guest
 
Join Date: Dec 2012
Posts: 1,003
Quote:
Originally Posted by jtur88 View Post
Is there any other part of the human body that can vary that much in size from one healthy person to another?
Bellies and buttocks? Come to think of it, hands also; specifically male ones.
  #10  
Old 06-23-2016, 01:58 PM
md2000 md2000 is offline
Guest
 
Join Date: Feb 2009
Posts: 13,243
Quote:
Originally Posted by robby View Post
My WAG: women's breasts are a secondary sex chacteristic that, for many men, heavily influences their attractiveness. This in turn affects whether or not women with certain breast chacteristics are likely to reproduce and pass the relevant genes on to their progeny.

All men do not have the same preferences for a given breast size (which is also affected by social factors, I expect), so it is not surprising that a wide variation of breast sizes might arise.
There's this, but I'll argue the opposite. Beyond a certain basic point, men are not particularly choosey. Within a certain range, breast size has no impact on, say, ability to feed a child properly. So as long as breasts are not so big they cause medical issues, and not so small that the children starve, any size is acceptable in an evolutionary sense.

It appears to me from random observation, that while approximate breast size is hereditary, the variation in size is either easily mutated, or influenced by random genes, environment and nutrition, etc. so size could change a certain amount from one generation to the next. Perhaps size is very "adaptable".

There is decent variation in every culture, so I doubt that cultural influences have much result. I recall reading once about women in China with large breasts who complained it was perceived as a sign of promiscuity - but despite the negative (or positive, depending on gender viewpoint) connotations, there were still quite a few women so endowed.

Or, as I once mentioned when discussing this topic at the bar... "Anything over a mouthful is wasted, anyway."

One o the other guys replied (timing it so I was in the middle of taking a swig) "If that's the case, how come women never say the same about men?"
  #11  
Old 06-23-2016, 02:50 PM
JR Brown JR Brown is offline
Guest
 
Join Date: Mar 2006
Location: Boston, MA
Posts: 1,032
I don't know if anyone has come up with any even remotely plausible theories on variation in breast size; there are plenty of WAGs but no evidence. My suspicion is that it's a factor of, on the one hand, the degree of overall fat accumulation, and, on the other, random variation; the same as responsible for height / shape / side differences in any other body part.

Quote:
Originally Posted by md2000 View Post
Within a certain range, breast size has no impact on, say, ability to feed a child properly. So as long as breasts are not so big they cause medical issues, and not so small that the children starve, any size is acceptable in an evolutionary sense.
The adult female breast in humans is largely fat; the mammary glands and associated plumbing don't take up much space. Consequently, there is no "too small" to feed an infant; gorillas and chips nurse their young just fine with little breast development.
  #12  
Old 06-23-2016, 02:58 PM
Surreal Surreal is offline
Guest
 
Join Date: Mar 2002
Posts: 2,078
Quote:
Originally Posted by jtur88 View Post
What could account for the fact that human female breasts vary so widely in size, within a range that is considered normal?
Lots of women have large breasts due to the fact that they're overweight. Once you adjust for body weight I don't think there's much variability in breast size. Have you ever seen a thin woman with large natural breasts? Have you ever seen a morbidly obese woman (or man, for that matter) with small breasts? It's not common.
  #13  
Old 06-23-2016, 03:13 PM
Colibri Colibri is online now
SD Curator of Critters
Moderator
 
Join Date: Oct 2000
Location: Panama
Posts: 37,543
Quote:
Originally Posted by Surreal View Post
Have you ever seen a thin woman with large natural breasts?
It's not uncommon for me to see thin (or at least below average in weight) women with large natural breasts.

While weight and other factors account for some of the variation, there's still a lot of variation in women of low to average weight.
  #14  
Old 06-23-2016, 03:57 PM
Surreal Surreal is offline
Guest
 
Join Date: Mar 2002
Posts: 2,078
Quote:
Originally Posted by Colibri View Post
It's not uncommon for me to see thin (or at least below average in weight) women with large natural breasts.

While weight and other factors account for some of the variation, there's still a lot of variation in women of low to average weight.
I would consider the upper limit of being "thin" to be 100 lbs for the first 5 ft. of height, plus an addition 5 lbs for every inch of height beyond 5 ft. And most people would consider the lower limit of "large" breasts to be a D cup.

Not very women who fall within this weight range will have natural D cups. I would guess that Russia would have the largest concentration of such women.
  #15  
Old 06-23-2016, 04:07 PM
Fear Itself Fear Itself is offline
Charter Member
 
Join Date: Apr 1999
Location: Flavortown
Posts: 34,324
Quote:
Originally Posted by jtur88 View Post
Is there any other part of the human body that can vary that much in size from one healthy person to another?
Ears, noses and feet?
  #16  
Old 06-23-2016, 04:26 PM
janeslogin janeslogin is online now
Guest
 
Join Date: Aug 2008
Location: Nevada
Posts: 2,163
Quote:
Originally Posted by jtur88 View Post
...Is there any other part of the human body that can vary that much in size from one healthy person to another? Or, for that matter, in any other species of animal?
I vaguely remember from my university days there is a statistical method where one measures all distances from some point, performs some arithmetic, squaring and summing and square-rooting -some such - to determine how similar or different curves are. Breast attracting so much attention, some one must have done a 3-D variation and compared them to other body parts.
  #17  
Old 06-23-2016, 04:44 PM
watchwolf49 watchwolf49 is offline
Guest
 
Join Date: Dec 2009
Location: State of Jefferson
Posts: 7,619
I'll be hard pressed to find the citation on this ... but it does have a certain logic. What a man finds attractive in a woman is the hip-to-waist ratio ... a nice broad birth channel delivers healthier children AND better odds the mother herself doesn't die ... it's only been in the past hundred years that deliveries became routinely survivable.

Obviously there's more to this and also obvious is we really don't know what makes us attractive to one another ... seems like all the research winds up as being inconclusive.

Beer ... that's gets everybody laid ...
  #18  
Old 06-23-2016, 04:56 PM
beowulff beowulff is offline
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 14,963
Quote:
Originally Posted by Surreal View Post
I would guess that Russia would have the largest concentration of such women.
No - Poland.

(At least, from my admittedly unscientific observation. Polish women are by far the most commonly thin-waisted and busty. And, beautiful , if I might add).
  #19  
Old 06-23-2016, 04:57 PM
aceplace57 aceplace57 is online now
Guest
 
Join Date: Oct 2009
Location: CentralArkansas
Posts: 22,580
Asian women are often smaller breasted. they are often very thin too.
  #20  
Old 06-23-2016, 05:01 PM
aceplace57 aceplace57 is online now
Guest
 
Join Date: Oct 2009
Location: CentralArkansas
Posts: 22,580
Cite a gene study on why Asians have unique traits
http://mobile.nytimes.com/2013/02/15...tic-level.html
  #21  
Old 06-23-2016, 05:04 PM
md2000 md2000 is offline
Guest
 
Join Date: Feb 2009
Posts: 13,243
Another factor might be fat accumulation. As mentioned by others, the breasts contain a large amounts of fat. My general observation again has been that fat distribution can vary - some layer it on lower more on the butt, some higher, some around the middle, some mainly on the stomach, some all over... especially for women. Generally, men accumulate fat either mainly on the stomach, or all over. So there may not exactly be a breast-size gene as a "where shall I store accumulated fat" gene that gives a certain amount of preference to the breasts.
  #22  
Old 06-23-2016, 05:54 PM
Trinopus Trinopus is offline
Member
 
Join Date: Dec 2002
Location: San Diego, CA
Posts: 22,851
I'm not sure of this, so please, someone, help me out... But wouldn't it be polygenetic? (As opposed to blue eyes, which are brought out by a single gene.) Like skin color: there isn't just one gene for "dark skin," but several genes, so you can get gradations of color.

Another argument for it being polygenetic is that mothers and daughters can differ very widely in breast size. There is some heritable correlation -- larger mothers tend to have larger daughters -- but there are so many exceptions that it can't be a really simple genetic heritage.

Or maybe I'm wrong...

(ETA: also, diet, including some food additives/contaminants that are so influential, they gave even boys breasts.)
  #23  
Old 06-23-2016, 05:58 PM
Urbanredneck Urbanredneck is offline
Guest
 
Join Date: Mar 2014
Posts: 5,681
A bigger question is why do breasts make men act so dumb?
  #24  
Old 06-23-2016, 07:20 PM
Hail Ants Hail Ants is offline
BANNED
 
Join Date: Jan 2000
Location: NY USA
Posts: 7,635
It's been a while since I read it, but in socio-anthropologist Desmond Morris' book The Naked Ape he posits the idea that large, permanently swollen human female breasts evolved after walking upright, as a way of mimicking the curvy round shape of a woman's ass. IOW it makes her look sexy (while standing on two legs) from both front and behind.

I don't know if there's any official statistics, but I would guess that average size breasts are, well, the average. That overall they don't really vary that much in size, that extra-large or small ones are statistical anomalies. But they all get noticed roughly equally because, well, guys are hardwired to notice them no matter what.
  #25  
Old 06-23-2016, 07:26 PM
Flyer Flyer is offline
Guest
 
Join Date: Feb 2012
Location: Colorado
Posts: 2,678
Quote:
Originally Posted by Surreal View Post
I would consider the upper limit of being "thin" to be 100 lbs for the first 5 ft. of height, plus an addition 5 lbs for every inch of height beyond 5 ft. And most people would consider the lower limit of "large" breasts to be a D cup.

Not very women who fall within this weight range will have natural D cups. I would guess that Russia would have the largest concentration of such women.
Quote:
Originally Posted by beowulff View Post
No - Poland.

(At least, from my admittedly unscientific observation. Polish women are by far the most commonly thin-waisted and busty. And, beautiful , if I might add).
It's basically a 3-way tie between Russia, Ukraine, and Poland for the highest per-capita concentration of beautiful women.
  #26  
Old 06-23-2016, 07:31 PM
Critical1 Critical1 is offline
Guest
 
Join Date: Nov 2000
Posts: 3,455
The short answer is because evolution never weeded out either small or large (or in between) breast sizes. As to why some women have huge ones is probably the bigger question since our ape ancestors have essentially none. Random mutation that does not increase the likely hood of an early death is a mutation that is likely to spread. If if confers an actually benefit to survival then it is very likely to spread.

or I have no idea either.
  #27  
Old 06-23-2016, 09:35 PM
MLS MLS is offline
Charter Member
 
Join Date: Mar 2003
Location: New Jersey
Posts: 7,841
Quote:
Originally Posted by Trinopus View Post
I'm not sure of this, so please, someone, help me out... But wouldn't it be polygenetic? (As opposed to blue eyes, which are brought out by a single gene.) Like skin color: there isn't just one gene for "dark skin," but several genes, so you can get gradations of color.

Another argument for it being polygenetic is that mothers and daughters can differ very widely in breast size. There is some heritable correlation -- larger mothers tend to have larger daughters -- but there are so many exceptions that it can't be a really simple genetic heritage.

Or maybe I'm wrong...

(ETA: also, diet, including some food additives/contaminants that are so influential, they gave even boys breasts.)
Genes come to a woman from her father as well as from her mother, remember.

If a daughter's shape is unlike her own mother, look at her paternal female relatives. My sister and I are both about average to below average in breast size. My niece and my older daughter are both very well endowed. So were my mother-in-law and my sister's mother-in law.

I remember shortly after my niece achieved puberty she walked past my sister and me as she was going outside to sunbathe. We both looked at her, and at each other, and commented, "Where did all THAT come from?"
  #28  
Old 06-23-2016, 10:45 PM
Trinopus Trinopus is offline
Member
 
Join Date: Dec 2002
Location: San Diego, CA
Posts: 22,851
Quote:
Originally Posted by MLS View Post
Genes come to a woman from her father as well as from her mother, remember.

If a daughter's shape is unlike her own mother, look at her paternal female relatives. . . .
Fair enough; but, again, how strong is the correlation? Is my notion of a polygenetic cause still viable?

(Also, the mother is the most significant relevant contributor, with aunts and uncles being only a quarter as relevant, with further halving at ever further distance along the family tree.)
  #29  
Old 06-24-2016, 02:28 AM
BigT BigT is offline
Guest
 
Join Date: Aug 2008
Location: "Hicksville", Ark.
Posts: 32,988
Quote:
Originally Posted by Trinopus

(Also, the mother is the most significant relevant contributor, with aunts and uncles being only a quarter as relevant, with further halving at ever further distance along the family tree.)
No, because the father's genes are just as significant. Just because they aren't expressed in him doesn't mean they aren't there.

Looking at paternal relatives is just about trying to guess at what genes the father passed on. An aunt passed absolutely no genes to her niece.
__________________
sig for testing purposes only
  #30  
Old 06-24-2016, 03:47 AM
Carl Pham Carl Pham is offline
Guest
 
Join Date: Nov 2010
Posts: 293
Because they can. You're misunderstanding genetics. Natural variation through random mutation will generally cause individuals to have quite significantly varying features, particularly for such simple characteristics as size. What natural selection generally does is rein in these variations, when they compromise some aspect of function that impacts survivability and breeding success. Hence, features of our genome that are absolutely mission-critical, e.g. certain basic enzymes for respiration, are exceedingly well conserved. No one has the slightest variation in them. Similarly, the size, shape and structure of the heart or airway or spinal cord is very consistent, since nearly any experiment along different lines is promptly fatal. In short, what needs evolutionary explanation in terms of functionality is uniformity of features, not variation. Variation is natural. Uniformity is not.

Breasts can vary in size wildly with essentially no impact on survivability. Furthermore, the existence of wide variation also implies that variation has almost no impact on breeding success, either (otherwise there would be selection for some optimal size). Which implies, as one might guess, that a woman's breeding success is not significantly impacted by her breast size, within a wide range. In short, there's a good supply of men who like them in almost any ordinary size.

By the way, an interesting side note on this is that breast size varies much more interwoman than intrawoman. That is, a woman may have big or small knockers, but her right is likely very close in size to her left. That actually needs explaining. Why the symmetry? It could be there is a significant hit on survivability (unlikely) or breeding success (seems more reasonable) with significant asymmetry. There is a general argument that humans are unusually sensitive to asymmetry and consider it ugly. I don't think anyone has a good argument for why that would be, though.

But it's also possible this occurs accidentally, e.g. that the same kinds of mechanisms control breast symmetry as control, for example, leg symmetry, which is clearly required for survivability. Hence the breasts are symmetric as an accidental side-effect of more essential symmetry, e.g. in limb size. But on the other hand, the human body has nontrivial asymmetry, e.g. in its internal organs, so why would symmetry of the breasts be a natural consequence of essential symmetry, when for example the lungs aren't bound by it? If development mechanisms allow the lungs and neural circuitry to be asymmetrical, why do they not allow for significant asymmetry in boobs? It may indeed come back to the possible preference we have for breeding partners that look very symmetrical on the outside (we can see whether her nipples are on a perfect horizontal, but we can't tell her liver is tremendously lopsided, so the liver is free to vary and seek some more optimal shape and location, while the nipples cannot).
  #31  
Old 06-24-2016, 05:20 AM
bardos bardos is offline
Guest
 
Join Date: Feb 2003
Location: Maui
Posts: 828
Not sure how this relates, but I spent a couple of decades breeding goats, and naturally one chooses mothers who are the best milkers with the best "breasts", udders. What I found, my experience has shown me, is that the daughters hardly ever will have the same udders as the mother. It's a crapshoot. YMMV
  #32  
Old 06-24-2016, 06:26 AM
Mijin Mijin is offline
Guest
 
Join Date: Feb 2006
Location: Shanghai
Posts: 7,819
At the risk of starting a whole new level of jokes, another organ which varies a lot in size (especially if we consider volume instead of just length) is the penis.

Which suggests to me the hypothesis that features that may have been subject to sexual selection in humans have gone through a lot of change in a relatively short time and therefore show a large distribution.

Then again, there are other, non-sexual organs showing a large distribution as others have pointed out (e.g. noses), so maybe there really is no anomaly to solve here?
  #33  
Old 06-24-2016, 06:45 AM
Chronos Chronos is offline
Charter Member
Moderator
 
Join Date: Jan 2000
Location: The Land of Cleves
Posts: 73,180
I suspect that it's closely related to the fact that our breasts are so much larger than those of our closest relatives (and correspondingly, than our fairly recent ancestors). We usually have big breasts because reasons, but we sometimes have breasts that are closer to chimp breasts (though very few women have breasts that are actually as small as a chimp's).

The same reasoning could be applied to the penis.
  #34  
Old 06-24-2016, 08:13 AM
Isilder Isilder is offline
Guest
 
Join Date: Mar 2013
Posts: 4,194
Quote:
Originally Posted by aceplace57 View Post
Asian women are often smaller breasted. they are often very thin too.
And generally have less trouble with their new borns not suckling.


Europeans evolved in the land with lots of mammal domesticated animals and harsh winters.

WAG So the mother needed to store fat in obese amounts, to survive winter, and could feed the baby on animals milk if the fat destroyed her own mammary glands abilities. With the animal milk available, the babies that didnt suckle would survive and pass along the trait for lack of instinct to suckle the nipples of of an obese mother, and to be obese, to their descendants.!

Meanwhile in asia, no pressure to become obese, and a nonsuckling baby died.
  #35  
Old 06-24-2016, 08:15 AM
Gedd Gedd is offline
Guest
 
Join Date: Jan 2010
Location: Columbus, Ohio
Posts: 1,706
Quote:
Originally Posted by Carl Pham View Post
[Snip]

But it's also possible this occurs accidentally, e.g. that the same kinds of mechanisms control breast symmetry as control, for example, leg symmetry, which is clearly required for survivability. Hence the breasts are symmetric as an accidental side-effect of more essential symmetry, e.g. in limb size. But on the other hand, the human body has nontrivial asymmetry, e.g. in its internal organs, so why would symmetry of the breasts be a natural consequence of essential symmetry, when for example the lungs aren't bound by it? If development mechanisms allow the lungs and neural circuitry to be asymmetrical, why do they not allow for significant asymmetry in boobs? It may indeed come back to the possible preference we have for breeding partners that look very symmetrical on the outside (we can see whether her nipples are on a perfect horizontal, but we can't tell her liver is tremendously lopsided, so the liver is free to vary and seek some more optimal shape and location, while the nipples cannot).
Studies have shown people that are more symmetrical are rated as more attractive, possibly because more symmetrical people tend to have greater masculine or feminine characteristics. (And they make better dancers)
  #36  
Old 06-24-2016, 08:22 AM
Hari Seldon Hari Seldon is offline
Member
 
Join Date: Mar 2002
Location: Trantor
Posts: 11,234
It's virtually certain to be some sort of sexual selection. A more interesting question is why, in some societies, men fetishize large breasts, while others appear not to. Thus in some countries, women on average have rather large breasts and in others they tend to have small ones.

It is possible for sexual selection to get out of hand and even lead to extinction. Read about the Irish elk.
  #37  
Old 06-24-2016, 04:13 PM
Trinopus Trinopus is offline
Member
 
Join Date: Dec 2002
Location: San Diego, CA
Posts: 22,851
Quote:
Originally Posted by BigT View Post
No, because the father's genes are just as significant. Just because they aren't expressed in him doesn't mean they aren't there.

Looking at paternal relatives is just about trying to guess at what genes the father passed on. An aunt passed absolutely no genes to her niece.
Sorry; you're right. I was reducing the importance of more and more distant relatives, by the appropriate powers of 1/2. Yes, the father contributes one of the X chromosomes, which, presumably, governs female breast development.
  #38  
Old 06-24-2016, 04:56 PM
doubleminus doubleminus is offline
Guest
 
Join Date: Jan 2013
Posts: 292
Quote:
Originally Posted by Carl Pham View Post
Because they can. You're misunderstanding genetics. Natural variation through random mutation will generally cause individuals to have quite significantly varying features, particularly for such simple characteristics as size....).
Well, not quite. A very slight survival difference is enough to drive evolution. For example a 1/10,000 decrease in survivability will result in the trait being reduced to about a third of its initial incidence in 10,000 generations or perhaps 200k years in humans. And obviously, larger than necessary breasts are bad for posture, running and consume resources. Thus there must be some advantages for them, such as sexual selection via the handicap principle, and if they can also store fat in addition to be attractive to males, so much the better.

In a nutshell, women have large breasts not because they are easy, but because they are hard, and for the same reasons.
  #39  
Old 06-24-2016, 05:39 PM
TriPolar TriPolar is online now
Guest
 
Join Date: Oct 2007
Location: rhode island
Posts: 37,454
Quote:
Originally Posted by Carl Pham View Post
Because they can. You're misunderstanding genetics. Natural variation through random mutation will generally cause individuals to have quite significantly varying features, particularly for such simple characteristics as size. What natural selection generally does is rein in these variations, when they compromise some aspect of function that impacts survivability and breeding success. Hence, features of our genome that are absolutely mission-critical, e.g. certain basic enzymes for respiration, are exceedingly well conserved. No one has the slightest variation in them. Similarly, the size, shape and structure of the heart or airway or spinal cord is very consistent, since nearly any experiment along different lines is promptly fatal. In short, what needs evolutionary explanation in terms of functionality is uniformity of features, not variation. Variation is natural. Uniformity is not.
Agreeing here. Breasts are uniquely human, that is the large amount of fat covering mammary glands is unique. That means this characteristic hasn't undergone the long term evolution of other human characteristics that are incrementally changed from our ancestors until reaching an equilibrium with function and survival.
  #40  
Old 06-24-2016, 06:17 PM
Little Nemo Little Nemo is offline
Charter Member
 
Join Date: Dec 1999
Location: Western New York
Posts: 75,136
Quote:
Originally Posted by jtur88 View Post
Is there any other part of the human body that can vary that much in size from one healthy person to another? Or, for that matter, in any other species of animal?
Quote:
Originally Posted by Ignotus View Post
Bellies and buttocks? Come to think of it, hands also; specifically male ones.
Quote:
Originally Posted by Fear Itself View Post
Ears, noses and feet?
I would dispute these suggestions. Breasts have a much greater range of sizes than the other body parts mentioned, even in women of the same overall size. You could have two women who are the same height and general build but one of them has breasts that are four times the size of the other's. You're not going to find two people like that where one of them has hands or ears that are four times the size of the other's.
  #41  
Old 06-25-2016, 04:11 AM
Dereknocue67 Dereknocue67 is offline
Guest
 
Join Date: Jan 2010
Location: Norfolk, VA
Posts: 1,030
The variation in breast size is probably due to the diet of the chicken. I prefer the thigh area.
  #42  
Old 06-26-2016, 10:19 AM
Myglaren Myglaren is offline
Charter Member
 
Join Date: Sep 2003
Location: Loonyland
Posts: 1,655
Quote:
Originally Posted by aceplace57 View Post
Cite a gene study on why Asians have unique traits
http://mobile.nytimes.com/2013/02/15...tic-level.html
Why Asians/East Asians and not Orientals?
There is a huge difference in the appearance of Orientals to Asians.
  #43  
Old 06-26-2016, 01:59 PM
Randolph Randolph is offline
Member
 
Join Date: Sep 2002
Location: NxnyC
Posts: 1,088
Well, sure. Some are rugs, some are people.
  #44  
Old 06-26-2016, 02:07 PM
Myglaren Myglaren is offline
Charter Member
 
Join Date: Sep 2003
Location: Loonyland
Posts: 1,655
Persian rugs?
  #45  
Old 06-26-2016, 02:41 PM
Mangosteen Mangosteen is offline
Guest
 
Join Date: Jul 2005
Location: Namche Bazaar
Posts: 2,136
Quote:
Originally Posted by Isilder View Post
And generally have less trouble with their new borns not suckling.


Europeans evolved in the land with lots of mammal domesticated animals and harsh winters.

WAG So the mother needed to store fat in obese amounts, to survive winter, and could feed the baby on animals milk if the fat destroyed her own mammary glands abilities. With the animal milk available, the babies that didnt suckle would survive and pass along the trait for lack of instinct to suckle the nipples of of an obese mother, and to be obese, to their descendants.!

Meanwhile in asia, no pressure to become obese, and a nonsuckling baby died.
Winters are pretty cold in northern China, Mongolia, and northern Japan where A cups and small waists are the norm. Plenty of milk producing livestock around, too.
  #46  
Old 06-26-2016, 05:35 PM
md2000 md2000 is offline
Guest
 
Join Date: Feb 2009
Posts: 13,243
Another human characteristic with great variability (among all races, despite Bell Curve's misguided claims) is intelligence.

We'll skip the speculation about intelligence - breast size correlation.
  #47  
Old 06-27-2016, 10:23 AM
MacLir MacLir is offline
Guest
 
Join Date: Mar 2010
Posts: 543
Quote:
Originally Posted by Surreal View Post
Lots of women have large breasts due to the fact that they're overweight. Once you adjust for body weight I don't think there's much variability in breast size. Have you ever seen a thin woman with large natural breasts? Have you ever seen a morbidly obese woman (or man, for that matter) with small breasts? It's not common.
Granting the rarity, yes. In college, I regularly interacted with a young lady who was otherwise so slender her ribs showed above her (ample) cleavage. I am pretty certain there was no artificial enhancement involved, as this was the era of Women's Lib - meaning exactly what you think it does.
  #48  
Old 06-27-2016, 10:38 AM
MacLir MacLir is offline
Guest
 
Join Date: Mar 2010
Posts: 543
One hypothesis I have not seen mentioned is the possibility of humans having been influenced by a span of littoral, semi-aquatic living. (Supported by some characteristics humans share with known aquatic and semiaquatic animals, but other great apes do not.)

In this theory, the enlargement served a functional purpose of allowing infants to "get a grip" in the face of body hair reduction in order to feed more easily.

One of the popular texts on the subject
  #49  
Old 06-27-2016, 11:38 AM
KarlGrenze KarlGrenze is offline
Guest
 
Join Date: Mar 2001
Posts: 6,406
Quote:
Originally Posted by bardos View Post
Not sure how this relates, but I spent a couple of decades breeding goats, and naturally one chooses mothers who are the best milkers with the best "breasts", udders. What I found, my experience has shown me, is that the daughters hardly ever will have the same udders as the mother. It's a crapshoot. YMMV
Possibly because the ram came from a poor milking mom? In dairy industry, the males are kept based on how good milkers their dams, and later daughters and grandaughters, are. It is considered poor managing to breed your top milkers with sperm or rams whose ewes arent top milkers.
  #50  
Old 06-27-2016, 12:09 PM
robby robby is offline
Charter Member
 
Join Date: Dec 2000
Location: Connecticut, USA
Posts: 5,113
Quote:
Originally Posted by md2000 View Post
...We'll skip the speculation about intelligence - breast size correlation.
Actually, I think that it is well-established that larger breasts on women tends to decrease the intelligence of men in the vicinity.
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:26 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2017 Sun-Times Media, LLC.

 
Copyright © 2017