From an evolutionary perspective, why do women have bosoms?

[Nan]

lol! From the link provided:

The question of the steatopygia of some of the figurines has led to numerous controversies. The issue was first raised by Édouard Piette, excavator of the Brassempouy figure and of several other examples from the Pyrenees. Some authors saw this feature as the depiction of an actual physical property, resembling the Khoisan tribe of southern Africa, while others interpreted it as a symbol of fertility and abundance. It must be noted in this context, that not all Palaeolithic female figurines are rotund or have exaggerated feminine features. Also, not all are devoid of facial features.

The Venus of Willendorf and the Venus of Laussel bear traces of having been externally covered in red ochre. The significance of this is not clear, but is normally assumed to be religious or ritual in nature—perhaps symbolic of the blood of menstruation or childbirth.

All generally accepted Paleolithic female figurines are from the Upper Palaeolithic. Although they were originally mostly considered Aurignacian, the majority is now associated with the Gravettian and Solutrean. In these periods, the more rotund figurines are predominant. During the Magdalenian, the forms become finer with more detail; conventional stylization also develops.

 

[junglebeast]

But OP said larger breasts don't increase milk production, which if correct significantly weakens this argument (in my opinion).

That statement may be roughly true in general but I haven't seen convincing proof that a girl that is completely flat chested (no boobs at all) can produce just as much milk as a busty girl. I find that to be a dubious claim, as breastmilk is produced in the breast.

Regardless, the breasts will become enlarged during breast feeding, which is all that is required to make enlarged breasts a characteristic sign of femininity, especially when ancient women were talking around topless with suckling children all the time.

Further, it makes a distinction between fertile women and infertile women, because a girl with lactating breasts has already had a baby, showing that she is capable of giving birth. Thus, being attracted to women with swollen boobs as opposed to the flat chested girls who can't seem to give birth may increase the rate of successful reproduction.

Once men have evolved a desire for enlarged boobs, women may evolve larger boobs while not pregnant so as to attract those men that have developed the desire for large boobs.

And to recapitulate my stance on why modern men often do not seem to share this desire for "large boobs," I believe the reason is because ancient women had much more active lifestyles and did not eat so much, so a modern girl with the same genetic makeup as an ancient girl will have more breast fat (and overall) fat than the ancient girl, which we have developed an attraction for...because most men probably didn't evolve an attraction towards enormous boobs, but rather slightly enlarged boobs relative to other males.

You will find that even those men who typically say they prefer small boobs (such as myself) still do prefer there to be SOME boob...so they are not completely flat chested. The men who do prefer completely flat chested are more likely just pedophiles.

 

[Saladsamurai]

women with small boobs are usually unattractive.

wtf?

 

[rootX]

wtf?

OP:

From an evolutionary perspective, why do women have bosoms?

and

I think probably the easiest way to make it possible to be falsified would be to see if there's a relationship between bosom shape/size and how much money a woman's husband earns?

Simple answer:

women with small boobs are usually unattractive.

He asked for opinions and I gave one of mine.

(Note that attractive/unattractive are subjective words.)

 

[arildno]

women with small boobs are usually unattractive.

Why the inserted words "with small boobs"??

 

[rootX]

Why the inserted words "with small boobs"??

I should have used "without boobs".

 

[WhoWee]

The men who do prefer completely flat chested are more likely just pedophiles.

Or perhaps they fell in love with the person - who is so equipped?

 

[tyroman]

From;
http://en.wikipedia.org/wiki/Venus_figurines

"The female figures, as part of Upper Palaeolithic portable art, appear to have no practical use in the context of subsistence. They are mostly discovered in settlement contexts, both in open-air sites and caves; burial contexts are much more rare."

Yeah, let's bury him with his Playboy collection! LOL

 

[junglebeast]

Or perhaps they fell in love with the person - who is so equipped?

Sure, a man can fall in love with a flat chested girl...but my statement was only in regards to men who "prefer [women] completely flat chested." I suppose you could argue that some men develop a preference for flat chested women because it reminds them of a former lover who was flat chested, but that's a stretch...

 

[Jimmy Snyder]

I think its sad to for somebody to think that attraction is a byproduct of society. You can't teach someone to be attracted to specific features.

I can't speak to the sadness issue, but the specific features that attract are different in different societies. The Japanese male is attracted by the nape of a woman's neck. How can you explain that except that the attraction is learned?

 

[Proton Soup]

Sure, a man can fall in love with a flat chested girl...but my statement was only in regards to men who "prefer [women] completely flat chested." I suppose you could argue that some men develop a preference for flat chested women because it reminds them of a former lover who was flat chested, but that's a stretch...

sexuality is complicated. don't forget that some men may prefer women with more masculine features and vice versa. some are bisexual. and some have fetishes, perhaps based on some early imprinting.

 

[Moonbear]

Further, it makes a distinction between fertile women and infertile women, because a girl with lactating breasts has already had a baby, showing that she is capable of giving birth. Thus, being attracted to women with swollen boobs as opposed to the flat chested girls who can't seem to give birth may increase the rate of successful reproduction.

Unless I have completely misunderstood your post, are you suggesting that larger breasts are a sign of promiscuity? Otherwise, if you've already been successful at reproduction with SOME OTHER man, how is it a helpful indicator to a man who has not fathered her children?

I'm not actually saying you're wrong, just that's what comes to mind from your comments. Who knows...promiscuity may have been much more common and more desirable than monogamy sometime in the past to make it evolutionarily relevant...or at least serial monogamy. It's not that entirely far-fetched, as I think about it.

 

[junglebeast]

Unless I have completely misunderstood your post, are you suggesting that larger breasts are a sign of promiscuity? Otherwise, if you've already been successful at reproduction with SOME OTHER man, how is it a helpful indicator to a man who has not fathered her children?

Not so much promiscuity...

If a woman is breastfeeding, then she has successfully birthed a child (assuming she's not caretaking), thus her enlarged breasts are a sign of fertility. If other women are dying in childbirth due to being too small, having egg issues, or other things, then it may be evolutionarily advantageous for men to be attracted to women who have proven themselves to be fertile in this way. This could apply to other men, or to the same partner that gave her the first child.

Secondly, a man is more likely to stay with the female, protect and care for her and the child, if he remains attracted to her. Thus, it makes sense for a man to be attracted to the enlarged breasts of his mate for this other reason as well.

 

[billiards]

Obviously men do find breasts attractive, but I don't think it's particularly good evolutionary science to say "women evolved breasts because men found them attractive". I could accept a sort of iterative progression, a kind of feedback loop that propagated protruberances of the female chest involving stepwise increases in attractiveness related to fertility -- but according to the evidence presented in this post magnitude of breast is not the issue so why would the breast continue to grow beyond the critical "fertility level"?? Furthermore, if breast size really is an indicator of fertility (in mammals), then why haven't other animals evolved breasts by the same reasoning??

 

[TheStatutoryApe]

Sure, a man can fall in love with a flat chested girl...but my statement was only in regards to men who "prefer [women] completely flat chested." I suppose you could argue that some men develop a preference for flat chested women because it reminds them of a former lover who was flat chested, but that's a stretch...

A flat chested woman can have other feminine features. I've personally found myself rather attracted to a couple of women in my past that were flat chested but had very wide hips (I'm not a breast man to begin with). The advantage small breasted / flat chested women have is that they do not really wind up with 'withered' or otherwise unattractive breasts.

...but according to the evidence presented in this post magnitude of breast is not the issue so why would the breast continue to grow beyond the critical "fertility level"?? Furthermore, if breast size really is an indicator of fertility (in mammals), then why haven't other animals evolved breasts by the same reasoning??

It was likely not so much an indicator of fertility but of health and fitness which have a positive correlation with fertility. A female's breasts increase in size if she gains weight which means she has a steady source of food and would make a good mate. A female's breasts can shrink/flatten if she is suffering from starvation, malnutrition, or even disease which all make the female a poor choice of mate.
Sooo.. males that found large breasted females attractive and mated with them were more likely to successfully reproduce passing on both the genes for females having larger breasts and the genes for males being attracted to larger breasts. So long as the size of the breasts remain good indicators of health, fitness, and fertility the genes will propagate more successfully. So long as the size of the female's breasts do not hinder her survivability and capacity to reproduce they will increase in size to be more successful at attracting a mate. The increased size need not have anything to do with functionality.
Other animals have utters and such but most species have their own sex characteristics for attracting mates such as long tail feathers, certain markings, a certain scent, ect ect. So they may not have developed breasts but they certainly developed something. Note also that most aesthetic sex characteristics have little to no survival value in and of themselves.

 

[Moonbear]

Not so much promiscuity...

If a woman is breastfeeding, then she has successfully birthed a child (assuming she's not caretaking), thus her enlarged breasts are a sign of fertility. If other women are dying in childbirth due to being too small, having egg issues, or other things, then it may be evolutionarily advantageous for men to be attracted to women who have proven themselves to be fertile in this way. This could apply to other men, or to the same partner that gave her the first child.

Secondly, a man is more likely to stay with the female, protect and care for her and the child, if he remains attracted to her. Thus, it makes sense for a man to be attracted to the enlarged breasts of his mate for this other reason as well.

I think there's a flaw in the reasoning here. In order for a woman to have become pregnant to develop the larger, more "attractive" breasts, she had to have attracted a man to get her pregnant the first time...when she still had small breasts.

And, actually, as women become more obese (and hence have much larger breasts), infertility increases.

Given the amount of variation there is in breast size, I don't think there really has been much selection for it at all beyond that there needs to be a minimum for feeding offspring (and even then, we've had several generations now where even that has not been necessary).

 

[TheStatutoryApe]

And, actually, as women become more obese (and hence have much larger breasts), infertility increases.

How many obese people do you think there were in prehistory?

Given the amount of variation there is in breast size, I don't think there really has been much selection for it at all beyond that there needs to be a minimum for feeding offspring (and even then, we've had several generations now where even that has not been necessary).

From what I understand greater variability of a characteristic among a species is a necessity for it to be successful and selected for. If just about any member of the species could be possessed of the characteristic to the same degree as any other it is no longer a useful indicator of anything and there is no reason to select for it.

 

[Hurkyl]

And, actually, as women become more obese (and hence have much larger breasts), infertility increases.

Hrm. If we're thinking along these lines, then shouldn't we note that obesity would correlate with surplus resources? This (along with the increase in infertility) would mean there is a need to increase how often humans mate.

 

[junglebeast]

I think there's a flaw in the reasoning here. In order for a woman to have become pregnant to develop the larger, more "attractive" breasts, she had to have attracted a man to get her pregnant the first time...when she still had small breasts.

Yes...but that's beside the point. The question was why women have breasts and why men are attracted to them. Nearly all women do have breasts which are larger than necessary for feeding offspring, and nearly all men (even those men who like small breasts) still find breasts to be attractive at some non-zero size.

And, actually, as women become more obese (and hence have much larger breasts), infertility increases.

But as has been already pointed out by someone else, men don't typically like such large breasts. And as I have pointed out twice, such large breasts would not have been selected for anyway, and are most likely a result of cultural changes rather than evolutionary selection.

Given the amount of variation there is in breast size, I don't think there really has been much selection for it at all beyond that there needs to be a minimum for feeding offspring (and even then, we've had several generations now where even that has not been necessary).

Not true, almost all women have a pronounced bosom, much more than the nearly flat chested girls which are perfectly capable of breast feeding.

Also, several generations of the option for store bought bottled cows milk is entirely insignificant to the evolution of breasts.

 

[Proton Soup]

I think there's a flaw in the reasoning here. In order for a woman to have become pregnant to develop the larger, more "attractive" breasts, she had to have attracted a man to get her pregnant the first time...when she still had small breasts.

of course, a young woman has no problems getting pregnant. youth is one of the things men prefer in a mate, and is the one thing all women try to preserve.

And, actually, as women become more obese (and hence have much larger breasts), infertility increases.

i doubt obesity was an issue for most prehistoric women. all the children to rear, starting sometime shortly after menarche, plus physical labor would keep the metabolic problems of sedentary obesity at bay. whatever extra fat she did gain would likely be seasonal.

 

[Math Is Hard]

i doubt obesity was an issue for most prehistoric women. all the children to rear, starting sometime shortly after menarche, plus physical labor would keep the metabolic problems of sedentary obesity at bay. whatever extra fat she did gain would likely be seasonal.

Or maybe due to a prosperous family. The buxom chick has the food access.

I think someone mentioned this before, but Desmond Morris opined that the boobs took over some of the sexual signaling that was the job of the female buttocks once we began to walk upright, Sort of a butt-on-the-chest thing. :)

I also seem to remember that he mentioned (or someone talking about his work did) that sexuality and taboo assigned to body parts still varies by culture. A U.S. or European woman caught nude will quickly cover her front, while in some African cultures, a woman caught nude will throw herself on her back to cover her buttocks.

 

[Jobrag]

Loren Booda #3 Men have nipples because as the foetus develops nipples start to grow before the gender of the child is determined.

Anything more then a handful (mouthful) is a waste.
Jobrag

 

[Nan]

It is societal today, rather than any sort of evolutionary trend or utility. DNA plays a large role in determining body shape, fat distributions, breast size, etc. What is attractive now is affected by fads and fashion, whether a woman or man pays attention to them and are influenced by them is the reason for different 'tastes' in what is attractive to them as individuals.

One can see in facial structure a lineage, in skin color, in body shape. A European woman will appear vastly different than an Asian woman. The characteristics extend beyond appearances to include the prevalence of particular diseases as inherited traits.

As our world becomes smaller, transportation available/easy and cheap; the former taboos absent of inter-racial marriages and breeding becoming more common, I suspect in the future, man/woman will appear more homogeneous and that is an evolutionary trend.

 

[Loren Booda]

If breasts' appearance were primarily to attract babies (of both genders), wouldn't woman as well as men have an obsession about them?

 

[Borek]

Furthermore, if breast size really is an indicator of fertility (in mammals), then why haven't other animals evolved breasts by the same reasoning??

Perhaps because human are erect, which makes breasts more visible.

 

[physicsdude30]

Obviously men do find breasts attractive, but I don't think it's particularly good evolutionary science to say "women evolved breasts because men found them attractive". I could accept a sort of iterative progression, a kind of feedback loop that propagated protruberances of the female chest involving stepwise increases in attractiveness related to fertility -- but according to the evidence presented in this post magnitude of breast is not the issue so why would the breast continue to grow beyond the critical "fertility level"?? Furthermore, if breast size really is an indicator of fertility (in mammals), then why haven't other animals evolved breasts by the same reasoning??

BOSOM SIZE AND ATTRACTIVENESS

I actually found an article that larger bosoms don't mean better looking, but rather there's an optimum peak at the top of a bell shaped curve for what men generally find most attractive. Too small, not good. Too large, not good. Not every man is the same, but there is a pattern for an optimum range. It's similar to how you hear about those fat/skinny women drawing studies, where women always think men prefer a full body shape a couple sizes skinnier than what drawing of women men really prefer. However, even men would vary in their responses in these studies.

One theory for why other animals don't have them is non-humans mostly only mate during fertility periods, while human couples mate all month long to form social intimate bonds that the others don't have. Some say that if breast do have to do with attraction, then that may be related to the reason for permanent breasts. Other apes only have breasts when nursing, but not during the other times, so some point to that. Many look at the fact that size/shape isn't related to potential for producing milk, but shape is related to fertility peak in life (although correlation doesn't necessarily prove causation from an evolutionary perspective). That's why I'm trying to get feedback on proposals on hypothetical studies to test the various hypotheses, just for sense of wonder sake.

 

[Borek]

promiscuity may have been much more common and more desirable than monogamy sometime in the past to make it evolutionarily relevant...or at least serial monogamy. It's not that entirely far-fetched, as I think about it.

Serial monogamy - in the worst case scenario - means no progeny due to genetical defects. My bet is that some promiscuity is programmed into women just to make their reproductive chances better (statsistics say that something like every tenth child is not a child of its 'legal' father).

Men are programmed to be much more promiscuous, but the logic behind seems to be a little bit different.

 

[physicsdude30]

That statement may be roughly true in general but I haven't seen convincing proof that a girl that is completely flat chested (no boobs at all) can produce just as much milk as a busty girl. I find that to be a dubious claim, as breastmilk is produced in the breast.

Regardless, the breasts will become enlarged during breast feeding, which is all that is required to make enlarged breasts a characteristic sign of femininity, especially when ancient women were talking around topless with suckling children all the time.

Further, it makes a distinction between fertile women and infertile women, because a girl with lactating breasts has already had a baby, showing that she is capable of giving birth. Thus, being attracted to women with swollen boobs as opposed to the flat chested girls who can't seem to give birth may increase the rate of successful reproduction.

Once men have evolved a desire for enlarged boobs, women may evolve larger boobs while not pregnant so as to attract those men that have developed the desire for large boobs.

And to recapitulate my stance on why modern men often do not seem to share this desire for "large boobs," I believe the reason is because ancient women had much more active lifestyles and did not eat so much, so a modern girl with the same genetic makeup as an ancient girl will have more breast fat (and overall) fat than the ancient girl, which we have developed an attraction for...because most men probably didn't evolve an attraction towards enormous boobs, but rather slightly enlarged boobs relative to other males.

You will find that even those men who typically say they prefer small boobs (such as myself) still do prefer there to be SOME boob...so they are not completely flat chested. The men who do prefer completely flat chested are more likely just pedophiles.

BREAST SIZE NOT RELATED TO MILK PRODUCTION POTENTIAL:

Something I found interesting, bosom size isn't related to amount of milk able to be produced. (http://ajol.info/index.php/nqjhm/article/view/12688 for one peer-review journal, plus there are many more peer-review journal articles that one can Google) How do we explain this? In addition, how do we explain why chimps and the other apes don't have permanent breasts, but only when they nurse their young? Regardless of what is true, if bosom size has a function other than the amount of milk a female can produce, then it would explain more empirical facts using less assumptions.

 

[Nan]

Men+women+logic does not equate. ;-)

 

[physicsdude30]

Or maybe due to a prosperous family. The buxom chick has the food access.

I think someone mentioned this before, but Desmond Morris opined that the boobs took over some of the sexual signaling that was the job of the female buttocks once we began to walk upright, Sort of a butt-on-the-chest thing. :)

I also seem to remember that he mentioned (or someone talking about his work did) that sexuality and taboo assigned to body parts still varies by culture. A U.S. or European woman caught nude will quickly cover her front, while in some African cultures, a woman caught nude will throw herself on her back to cover her buttocks.

I heard that too. I brainstormed an experiment to test the idea, such as below. I'm trying to think how to improve my experiment.