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Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsBreasts (and penises) are demonstrably Primarily Decorative
Last edited Sat Mar 30, 2013, 04:44 PM - Edit history (2)
Since attitudes about breasts are being discussed it is worthwhile to talk about the distinctive function of the human breast.
Adult female human beings have prominent breasts, even when not lactating. No other mammals do. (With the exception of farm mammals we have selectively bred to produce unnatural amounts of milk.) So we start out knowing that there is no practical baby-feeding reason for the prominent human breast when there's no baby to be fed. The infants of small-breasted women do not all die of starvation. Cats without kittens don't carry around eight bosoms... it would be a terrible waste of resources.
The structure of the non-lactating human breast is primarily tissue that is surplus to its ostensible function. That doesn't mean its structure is useless, by any means. Merely that its use is something other than base function of making milk.
The human penis is similarly 'useless.' The penis of a huge pound chest-beating silverback gorillaa masculine a creature as can beis no bigger than that of a prepubescent human male child. There is no practical reason for the human penis to have much size at all, and particularly when not erect. (Being able to write cursive with urine was not a key survival trait on the ancient African savannah.)
There is no practical benefit to having anything hanging out when running through bramble bushes and fighting badgers. And any weird survival function we try to concoct to explain a prominent penis will cash on the rocks of the fact that women survive with no penis at all. (Much like any attempt to come up with a non-sexual reason for antlers will demand the question how the females survive without them.)
When a creature has something that seems useless it is usually sexual in nature. Being bright red does not help a male cardinal find food and certainly doesn't help him avoid predators. It is about sex... about passing down genes, not about practical day-to-day survival. Antlers, peacock tails, non-camouflage markings, long tail feathers, crests... all are about sex.
That does not, however, necessarily mean that the human penis is designed to be attractive to women. Given what we know about people, it is likelier to be designed to be intimidating to other males. But traits used in sexual competition are still sexualabout passing genes along, not about the survival of the individual.
Recognizing all of this does not mean that we are required to have certain attitudes. And different societies have had differing attitudes about breasts... and hips. Scarlett O'Hara went to balls with her breasts almost hanging out and her waist conched in, but while the shape of her hips and legs were a complete mystery. A hoop skirt conceals entirely. In 1940s New York Scarlett would have been shunned for baring so much bosom on the street, but would have been able to wear close fitting skirts and nylons. But whether in New York or the old south everyone would have agreed that breasts and butts and hips were sexy in a way elbows were not. And Scarlet's decolletage was understood by all in 1860 to be a sexual display... merely a socially acceptable one in that time and place.
I have seen American breast fashions go from pointy to big and rounded to waifish to athletic to absurd plastic-hemisphere. I have seen an era (the late-1970s) when women wore bras only if sorely needed for support and Time magazine featured nipples in many issues. Today the forms of breasts are obscured almost entirely by stiff and padded clam-shell tops while the butt can be bared almost entirely. These things come and go... culture and fashion are powerful.
But despite cultural varriance, it is a mistake to think that male attraction to breasts and even female pride in breasts are entirely cultural creations. They are something diffuse but natural (which does not mean good) that is there to be shaped by culture.
And since the prominent form of human breasts is a mammalian anomaly requiring explanation, and since the evolutionary explanation is of a sexually atractive display, there is nothing odd in the notion that to men, breasts are features of sexual interest and are somewhat arrousing. Men differ in tastes, cultures differ in tastes and priorities, but breasts are (in addition to their practical function as mammary glands) a sexual display.
And that is a good thing about people. We have a pretty high level of built-in gender equality. Because we are socially monogamous, female adornment suggests the creation of higher demand than can or will be filled... to attract multiple suitors from which to choose. Human females compete with each other, to some degree, rather than being entirely mere bystanders to male competition and selection.
Kingofalldems
(38,469 posts)snooper2
(30,151 posts)russspeakeasy
(6,539 posts)cthulu2016
(10,960 posts)pretending for the moment that squirrels were like that, it would indicate that squirrels engage in "sperm competition" like chimpanzees do.
When females, by choice, force or instinct, tend to have the sperm of more than one male in them at the same time there is selection pressure for producing more and more sperm... to swamp the other guy's contribution numerically.
Chimps have unusually large balls. Gorillas, being mostly monogamous in harem arrangements, have no competition and thus have small testicles despite having many mates.
The big balls of dogs and cats are what we would expect in a species where females go into a "heat" period of being sexually indiscriminate.
Response to snooper2 (Reply #2)
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MineralMan
(146,325 posts)our front yard.
LiberalLoner
(9,762 posts)Why most women had those pointy things (the bras in the 60's created an odd pointy look...at least I thought it looked odd.)
tammywammy
(26,582 posts)Benton D Struckcheon
(2,347 posts)Link: http://en.wikipedia.org/wiki/The_Naked_Ape
Don't remember the ear lobe thing, but a highly entertaining book on this whole subject.
See also the last part of Lucy (about finding that fossil), where some anthropologist went on a long tear about how human evolution was driven by sex - he was mostly trying to explain the expressiveness of our facial expressions, and how upright walking and our large brain could all be explained by this. Another interesting read.
jerseyjack
(1,361 posts)feels good.
MineralMan
(146,325 posts)bright red buttocks as a sexual signal. I'm happy with our breasts, penes, and beards.
dawg
(10,624 posts)at least by primate standards.
But I don't think the purpose was to intimidate other males.
Humans, unlike other primates, have a tendency to pair-bond. This trait effectively doubled a parent's ability to care for and protect their offspring. Anything that enhanced the pair-bond tended to be reinforced via natural selection, and sexual satisfaction was a part of that.
MineralMan
(146,325 posts)dawg
(10,624 posts)It is seldom discussed, but this is one of the more drastic differences between us and the rest of the ape family. That, and the brain thing of course.
tech3149
(4,452 posts)I will admit that I love breasts, not large ones just those that fit the form of the owner. Breasts have a purpose as do penis's but the primary function is not the only function.
Breasts might be considered decorative as an enticement but really? Who want's to look at a penis and how does it enhance your appearance?
Prism
(5,815 posts)Response to cthulu2016 (Original post)
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RainDog
(28,784 posts)Because if the issue was just about intimidating other males, the scrotum would be tiny, like a gorilla, and it's not.
You probably read about the theory that the reason for the shape of the male penis might be to displace semen, I assume. The idea is that the glans forms a "scoop" that would displace other another male's sperm. This action has been observed in other species - so it's an adaptation that already has some success in other species.
Chimpanzee males have penises of different shape and a different strategy to ensure their sperm is favored among female chimpanzees who have sex with various males. Their sperm secretions are different. Their sperm forms a "plug" to seal off the cervix of a female after sex. The shape of the chimpanzee penis is thought to serve to get rid of this plug. A female chimpanzee mates with just about every male when she is in estrus.
One primatologist thinks the human penis is shaped the way it is to scoop out vaginal secretions - that oxytocin idea of encouraging pair bonds by sharing more than just a three second turn at just any female.
Most every primatologist these days would find a reason to consider that the vagina influenced the shape of the penis because the goal is fertilization for both parties.
You focus too much on male competition.
Our other closest primate relative doesn't have the same social structure as the chimpanzee, and they are more closely related to one another than to humans (they diverged from one another later) - and the three - common chimps, bonobos and humans, all diverged from gorillas even before - and all three have social structures that are different from gorillas.
This is another reason to doubt the male competition idea as the reason for the length of the human penis. When females have no choice, the penis is smallest compared to body size and dimorphism is far more prominent.
Human dimorphism is, again, more like pan than gorillas. Lucy is small - but there's no indication that a male austropith. was significantly larger than a female, at least the last time I heard anything about this subject.
Humans are not entirely monogamous.
This is evident in DNA research and in comparison to other species who either are entirely promiscuous or entirely monogamous, or in species with males and harems.
Humans have also used technology to change our social structures in a variety of ways. Humans have examples of cultures in which males control females, all property is inherited through sons, etc. Humans also have examples of cultures in which a female maintains control of her own property through her family line and the brother, rather than the man with whom a female has children, has the male "authority" in a family. In these cultures, women have more than one partner and do not lose standing in society by doing so because her family is where her resources are located - and in these cultures, children trace their ancestry through the mother.
So, we have examples of social structures in humans that exist in two different primate species - but neither of them absolutely tells us about our social structures before technology.
Since we're the only primates in which estrus is not advertised, it's pretty obvious there's some female agency going on there. The elevation of hormones that inclines a female toward sex also influence secondary sexual features, like breasts. So it's very likely that female interest in sex (and the hormonal soup that would create this) is the reason for breasts that remain enlarged even when they are not lactating.
Other primates don't and thus can't explain that for humans. However, it's obvious that there's a benefit to human females to be interested in sex even when they are not ovulating or else it would not have lasted as long as it has. This is an investment of energy in the female's body to maintain hormonal cocktails that are also part of the ovulation and lactation cycles.
The only other example we have of females that are interested in sex when they are not in estrus are bonobos, and they use sex to create social cohesion and to ease conflicts, rather than whaling on one another all the time. They're not homo or hetero - they're literally pan sexual.
Female bonobos have power within their communities.
...just to say - your assumption about male display being for other males isn't deserved based upon comparisons with other social structures and to female anatomy.
The present form of the human penis, reached over several million years of evolution, was orchestrated by the vagina of the human female. The multifunctional vagina serves as a birth canal, a component of the structural support for the internal pelvic organs, and as a coital organ. In this last function, it has had an evolutionary effect in shaping male sexual anatomy. Hominid fossils so far discovered show that the female pelvis evolved to accommodate the increasing size of the brain of the human infant. Larger cranial capacity necessitated a larger birth canal and, as a result of sexual selection, an increase in the size of the penis. Compared to that of the other great apes, the human penis is considerably larger, and evidence suggests that its unique configuration may also be a result of vaginal influence.
It has been proposed that the shape of the glans with its distinctive corona facilitates the scooping out of previously deposited semen, enabling the subsequent deposition of other genetic material. This is not a likely occurrence. The healthy vagina has a low pH to protect it from invading organisms. This intense acidity will kill all sperm not promptly reaching the safety of the cervical mucus. I suggest the evolutionary function of the glans and its corona is not to scoop out semen but vaginal secretions, which are then absorbed by the encompassing foreskin. The mucous membrane of the foreskin adjacent to the glans is highly absorbent, as evidenced by the increased susceptibility of the uncircumcised male to HIV. It has been suggested that there may be a glans protecting feature of the foreskin, but it is entirely possible that its primary function is to absorb behavior modifying chemical messengers from the female. Numerous studies have shown the vaginal mucosa to be secretory. In the primate rear-approach coital position, the corona rubs against the anatomically posterior wall of the vagina, the most dependent surface when the woman is standing, and therefore the place more likely to collect vaginal secretions. The deepest end of the posterior vagina is the cul de sac, which commonly contains a small amount of fluid. An analytical study of the vaginal secretions of an ovulating female for neuropeptides, such as pitocin and vasopressin, known to enhance pair bonding and protective behavior in the male, could be revealing. Sexual intercourse may be a medium of communication between humans older than language itself.