It seems to be controversial for some people that humans are a pair bonding species. Here’s a little piece of anatomical evidence that supports the contention that humans are pair bonders.
How do you get males to interact with you on an emotional level and as a person, maybe even get one of them to commit emotionally to you? You evolve breasts that look like ass cheeks so they will come around front and look you in the eye, at least for a while.
I don’t know what category this goes in, evolutionary psychology or evolutionary anatomy, but then again in this case there may be no separating them.
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Watching my wife breast feed convinced me that breasts are evolved for babies to have easier access to the nipple. Without that fat there, babies would have a lot of difficulty nursing;women would struggle hard to get their babies fed. That some men find this sexy is not the same thing as saying that breast evolved to suit the tastes of men. To me, that\’s putting the cart before the horse. Are babies cute and thus we find them cute? Or are babies babies and thus we find them cute?
(so many post failures…)
“That some men find this sexy is not the same thing as saying that breast evolved to suit the tastes of men. ”
That human breasts don’t look like chimp or gorilla breasts, but are considerably plumper and cheek-shaped is the point. The sexiness has zip to do with suckling or watching women nurse.
And I don’t buy the business about the extra fat being to help the baby suckle – show me even one mammal species where that is true. (And I am talking about natural species, not force bred mutants like Holsteins.)
Human female breasts are considerably larger than nursing infants requires, just as human male penises are considerably larger than chimps’ or gorillas’ are, which are obviously perfectly adequate for impregnating females. So something is going on here.
There are other anatomical differences that suggest pair-bonding.
Vasopressin expression in male humans and other pair-bonded male mammals for starters.
http://physiologyonline.physiology.org/content/21/2/146.full
http://www.pnas.org/content/105/37/14153.abstract
Human males have evolved more sperm then polygynous gorillas(actually this argument makes no functional sense at all but lets go with it) but less then promiscuous chimps. This is used as evidence that humans are ‘somewhere between the two’.
However there is another explanation for human male’s relatively abundant sperm. And that explanation is the occult nature of human female fertility.
For most mammals females advertise their fertility clearly, allowing for a precise synchronization of ovulation and sperm delivery. Not so much human females.
Our male hominid ancestors could have easily evolved extra sperm to ensure that, should a female be mated within a week prior to her fertile period, there would still be sufficient sperm to inseminate her.
This adaptation was likely made necessary by occult female fertility.
Also, the rate of cuckolding among humans has been estimated at 10%. This is unusually low for a pair bonded species. In some species the rate is as high(or higher) then fifty percent. Many bird species are at thirty percent.
With a ten percent cuckolding rate, humans pretty much qualify for genetic monogamy in addition to social monogamy. And, fact is, we may have evolved ways of combatting the toxic genetic effects of our hyper-monogamy.
Human infants are pathetic and feeble. More so than other animals. Notice that babies have flat noses? This is because of nursing. If their nose was bigger then the nipple would have a hard time getting past it and reach the baby’s mouth. So form is dictated by the situation. Similarly the human breast is evolved to help the baby and mother get the nipple into the baby’s mouth. If the nipple was flat againts the chest (which it isn’t on other mammals either) then the nursing woman would have to struggle harder to get the baby to latch on. It’s a simple matter of not being able to manipulate where the nipple goes without a breast under it. The breast is like a tool to manipulate the location and angle of the nipple in such a way that make nursing possible. Also, nursing is essential for human survival. Why wouldn’t female and infant bodies be evolved to suit this very important interaction?
I admit. I’m a bit confused though. Why is it so hard to have breasts be evolved for nursing AND men finding them sexy? I don’t understand the resistance to this notion. To me, it sounds like you are saying that women’s breasts are shaped the way they are because men find them sexy. And you are also rejecting the idea that nursing has anything to do with the shape of breasts. That in shaping the breast, that male sexual preference plays a bigger part than the demands of nursing? Really?
Do women find broad shoulders sexy? I think so. So are men’s shoulders broad because women find it sexy? Or maybe it has to do with men being stronger and having more muscle mass? It seems rather trivial to say that women find broad shoulders attractive because men have broad shoulders and not the other way around. Why is it not trivial in regards to breast?
Also, are breasts (or broad shoulders) sexualized in all cultures? We’ve all seen those documentaries of people living as they did thousands of years ago, like in the rain forest. Are breasts sexualized in those places? I don’t think so. Breasts are left exposed, nursing is done in public, and no one sems to bat an eye at it. Are the evolution of breasts really so instrically based on male sexuality? Again, I don’t think so.
In regards to sexuality, however, I think breasts (and broad shoulders) do act as a display of health and fertility. That breasts and broad shoulders evolve for other reasons (survival) first, then they act as a sexual display only after the fact.
And in regards to penis size. I’ll just mention that ducks have enormously large penises. They story of why is a good one. (this is a long post so really, honesly, not out of dismssiveness…google it) Are you also suggesting that the human male penis size and shape is dictated by the sexual preferences of women? I reject that notion as well. Knowing the story of ducks, can it have any relation to human penises? Or are duck penises also shaped and sized that way they are because of female duck preferences?
BB (Because breast) are selected for by sexually active males, they may also provide “fitness” information about the female. There may be a symmetry marker more clearly on display with engorged breasts – a type of “health certification”, a little like a peacocks’s tail maybe…
– With symmetry being the best tell for the ability to fight off diseases, infections and creepy crawlers.
There is coevolution to consider as well, more than one reason.
It seems to me that, although we have a strong tendency to pair-bonding, we also have a (probably weaker) tendency to polygyny, i,e. dominant males forming harems (there is obviously a certain degree of cheating under both systems). I suspect our ancestors, like chimps and gorillas, were harem-formers who evolved into pair-bonders, but a remnant of the ancestral behaviour remains.
@ Patrick
Chimps are promiscuous breeders, not pair bonders. Gorillas are polygynous.
Most female mammals are polyandrous–ie. they mate with multiple males. Polygyny is probably the least likely mating system for humans and probably only became feasible when a ‘Big Man’ was able to appropriate the resources of and make slaves of lower ranking men.
In other words it’s a result of civilization. It’s also likely the root cause of violence on a massive scale since harem societies produce father-deficient children(specifically sons) who then go on to be easily indoctrinated by authoritarian religions and naturally associate violence with manhood.
Involved fatherhood inoculates society against extreme violence and authoritarianism, IMHO. It’s also a practical impossibility in harem societies. A man takes two wives, his children are one fourth as fathered. A man takes four wives, his children get one sixteenth the fathering they need, etc. Till fathers might as well not exist and we live in a lord of the flies nightmare that’s only kept (partly) in check by draconian religious control.
Ok this is going to be somewhat adolescent, but what the hey, its my birthday. 🙂
“The bigger the titter the tighter the sweater all the better for us. You must, you must, you must increase your bust.” 😉
Elissa, I hadn’t even thought of the health signalling aspects. The same probably holds for beard growth, but breasts are of course going to go right across the whole species.
Oh, and welcome aboard!
Titfortat! HAPPY BIRTHDAY! Birthdays are important and it isn’t adolescent to let us know your date.
Pair-bonding does indeed seem to be the default model for human relationships. What a relief to know that as reasoning beings, we’re not limited to the tyranny of biology and instinct any more.
\”I admit. I’m a bit confused though. Why is it so hard to have breasts be evolved for nursing AND men finding them sexy? I don’t understand the resistance to this notion. \”
If this looks like resistance, DB, then I am not being clear. Of course they are both in humans, but that\’s not the point. They are both ONLY in humans. That\’s the point. The question is why are they both in humans, a very recent development, and let\’s be honest, a unique one, on the order of bipedalism for strangeness.
I don’t find the chestbutt theory very convincing. Breasts are too big a hindrance for something that could be achieved by something much much simpler, like say a red chest mark. I’ve seen breasts used as evidence of pair-bonding, but it was more in the context of concealed ovulation rather than “they look like a butt.” That is, if you can’t tell if a female is in heat, then it’s more advantageous to stick with her all month round than waste your time chasing after lots of women who might not even be ovulating.
(not to mention tits don’t look like any butts I’ve ever seen, unless they had push-up bras in the neolithic era)
How do boobs that look like ass cheeks become engaging in an emotional level? If an asset is sexually appealing it is simply that and a rather weak evidence to pair bonding. Early homo sapiens as animals don’t just look at boobs. If they find that they can’t do anything with these boobs – or have ejaculated doing so… dafuq – there’s no good reason to linger and continue looking at them when sexual activity is clearly at end. It’s not like the boobs were a piece of artwork that they can appreciate from afar. Human males have developed so that when you ejaculate you don’t want to do anything more with anything sexual. If it had, then women would be less complaining that men dislike cuddling after sex and such. Even if boobs developed to allure males – which they probably did concerning males’ natural inclination towards boobs – there’s very little to suggest this aided in genetic monogamy… if any.
I’m not suggesting there’s nothing biological inherent in long-term love or what you would prefer to call the hallmark for monogamy. There’s something neurologically different about long term love. Some guys I’m just attracted to with a strong instinctual crush but with little to no overtly erotic desires accompanying it, i.e. i don’t imagine having sex but engage emotionally. Personally, I agree with typhonblue that humans are somewhere between genetically monogamous and polyamorous, or that both instincts are simultaneously extant in a single human. Personally I feel that society needs to find a good balance between the two. If anything, I think this diversity in humans aided us in survival – although I still think that intelligence is highly underrated when it comes to human survivability.
It’s just that, so far, there’s little biological evidence given here that is convincing enough for me to buy.
“How do boobs that look like ass cheeks become engaging in an emotional level?”
They don’t. It operates at a sexual level.
” If an asset is sexually appealing it is simply that and a rather weak evidence to pair bonding. ”
It’s not evidence for pair bonding. It’s evidence that sexual connections were important enough for a permanent sexual display to become adaptive.
“Early homo sapiens as animals don’t just look at boobs. If they find that they can’t do anything with these boobs – or have ejaculated doing so… dafuq ”
Most men have more control than a quick shot fourteen year old.
“– there’s no good reason to linger and continue looking at them when sexual activity is clearly at end”
Well the point of a pair bond is that sexual activity is not at an end after one ejaculation. We are specifically not talking about a hook up culture. Right?