After the kids are bred and raised, is there any biological reason for a couple to stick together?
I’m not going to bother finding a cite for the exact % (I’ve heard different figures), but we all have heard that the divorce rate is pretty high these days. Is it possible we just aren’t meant to mate for life? I know I have my doubts.
In the olden days, women would often continuously have children until they couldn’t have any more. If you consider a woman while having and raising children would want to stay married, and that menopause occurs in the late 40s to early 50s, depending on nutrition and genetics, by the time her youngest child no longer needed constant care, and could be married off or be out working the fields or something, a woman would be in her late 50s to early 60s, so she’d only have a few more years left before dying.
So yeah, I’d say we’re meant to mate for life, “life” being the lifestyle of our ancestors. Women’s rights, birth control, and longer life expectancies have thrown a monkey wrench into the equation, and that’s why we’re seeing so many divorces – women simply have other options these days than being baby machines.
Before this discussion can get very far, I suspect somebody had better define “meant” and then follow up with who/what “meant” it.
If the meaning of “meant” is that we are biologically predisposed to choosing a mate for life, I’d say the evidence doesn’t support that.
If it’s more of s societal thing, then the answer could approach a “yes” with more support data. Even there, though, the numbers tend to lack heavy support.
We’re less like wolves and ducks than dogs and cats.
Two points: firstly, life used to be a lot harder and so we’re living a lot longer than we used to - 50 was considered old. Secondly, there’s the issue (hehe) of grandchildren. People didn’t travel very far, so the grandmother would be close by to help her daughter with the daughter’s children.
Well I meant “meant” in the sense of being biologically predisposed to it.
But how do you mean it could approach a yes as a societal thing? I’m guessing you’re saying society probably expects us to stick together for life? If that’s the case, I’m also curious as to why that may be. So I would be interested in the discussion going either direction.
Are we biologically predisposed to lifelong monogamy?
I’ve lost track of how many threads on this topic I’ve been involved in on these broads, so don’t expect any great enthusiasm for this debate, It’s been done to death.
But rest assured that within the next 5 posts someone will introduce Morris’ debunked claim that testicle size indicates polygamy or something.
The truth is that there is no way we can know what humans are predisposed to biologically. We are so unlike any other living creature that there is simply no valid comparison point. All we can do is look at human cultures, and that tells us that we are predisposed to anything and everything.
It seems incredibly unlikely that humans are biologically monogamous in the strictest sense, since monogamy as a trait only evolved in the past 2000 years. Prior to that, and often afterwards, all societies AFAIK accepted polygamy even if they didn’t encourage it. And as far as we can tell that has always been the case. The ‘normal’ human system seems to have always been a man and a small number of women.
Of course even within polygamous societies polygamy was/is usually fairly rare but the fact that it was universally tolerated suggests that monogamy is ‘unnatural’. That is further supported by the much higher death rates amongst males. Unless many women were remaining unmarried ‘primitive’ societies had to be broadly polygamous.
Even in polygamous societies couplings were usually serial. A couple would pair for an unspecified time, but at any time one or both partners could simply move on. The idea that marriage was a lifetime commitment is every bit as recent as the idea of polygamy and AFAIK is not found in any ancient societies.
So are we biologically predisposed to lifelong monogamy? Probably not, but there is no compelling scientific evidence either way.
While on vacation once I was talking to a fellow from (IIRC…it’s been awhile now) Saudi Arabia and we got into a discussion about it. He said that having more than one wife is expensive and often seen as more of a status symbol and that multiple wives are beyond the means of most. He also said that if the man wants a somewhat happy life with more than one wife he needs four or more of them. With two wives the first wife tends to dominate and make trouble for the second wife. With three he said two of the women will often form an alliance of sorts and gang up on the third woman and make her (and by extention the man) miserable. With four or more he said the dynamics were better and thus the man was happier.
Pulling my leg? I don’t know but it made a sort of sense to me for some reason but one can see even where allowed polygamy is not all that common if for no other reason than fiscal ones.
Language tells us that we are certainly not inherently a pairbonded species.
If we were, the expression “ex-mother” would be as reasonable as ex-wife.
While our social, and religious traditions recognize the inherent benefit of monogamy, the free expression of our character make it clear that however much we individually appreciate it, it is not biologically inborn for us to have a single mate for life. Neither is polyamory inherent in our genome. Both are expressions of individual choices.
Tris
I’m dubious. I see your point, I just think that’s a really bad example. After all many men (and even many women) are just as absent fom their children’s lives as from their spouses, yet we still don’t speak of ex-fathers or ex-mothers. The reason for that seems to be that a parent is biological fact that can’t be changed by estrangement. Spouse is a purely social arrangement. If a couple aren’t interacting in any way they cease to be spouses. If a parent ceases interact their children they remain just as genitically important and so can never be ex-parents.
For the same reason our language understands perfectly “I don’t know who my father is” but if someone says “I don;t know who my wife is” we immediately start trying decipher the figure of speech.
What is biologically inborn into us (humans)? I ask that seriously.
Is male human motivation (at the root of it all) to just take a shotgun approach and diddle as many females as we can get our paws on? Or are human males programmed to want to look after their offspring? The second option argues against having more than one mate. Human babies take a lot of care and a long time to raise to self-sufficiency which means a lot of work on behalf of the male to feed…the more offspring the harder it becomes and the greater the likelihood of failure. Pour all resources into one or two and better guarantee their continued existence or produce hundreds and hope a few will make it somehow? This doesn’t even take into account the effort of maintaining a harem when you have a dozen females and some young, upcoming stud has none and decides he could do with a few of yours and you have to fight to keep them.
As for females the calculation would seem to be different. Carrying a baby to term is biologically expensive not to mention looking after it once it is born. As a species someone has to be programmed to want to look after the newborn and that task definitely seems to be in the mother’s arena (remember I am talking from a strictly “animal” perspective…don’t get into a fuss over that). The mother certainly has it easier if the male sticks around to help. Further, it is not in her interest to see the male has other offspring to worry about with other females. She would much prefer to see the male devote all his efforts to raising her child. As such you would think she would discourage him from bringing other females in to the mix.
Where in all this is the predilection for polygamy in humans? Insects take the shotgun approach as they have no need for parental upbringing (I know there are some insects that seem to have some parental instincts but by and large they do not). It also doesn’t hurt that a female can punch out a few thousand offspring in short order and repeat it in short order. For higher animals (say lions) maintaining a harem makes some sense too. By having to defend his territory the females ensure only the best studs breed with them. The female’s offspring also, while needing some care, become self sufficient MUCH more quickly than human children. Humans, as described above, seem to need a different strategy. Looking at this it seems monogamy is the better bet for humans from a bilogical perspective.
Just thinking out loud…trash at will.
And as I said above, there is simply no way of knowing. As a species we are too unusual to give any validity to other species. And if we resort to studying our own species we seem to have a biological prediliction for just about anything imaginable (and quite few you hadn’t).
We can’t know, possibly and it doesn’t really. In that order. 
The thing is that humans are social animals. We don’t necessarily rely on just pair bonds, and I don’t think you’ve taken that into account.
If we take the other great apes and most human societies as a likely template then the default human troupe consists of a small number of related males and 1.5-3 times that many adult females. When females reach maturity they are expelled from the mother’s troupe and take up residence with an unrelated neighbouring troupe. And it’s quite astounding how widespread that pattern is amongst both great apes and human families. Women live with their husband’s families, men almost never live with their wives families.
Since all males in a troupe are going to be providing food for offspring, and since all males in a troupe will be closely related it becomes far more complicated than simply saying that the more offspring the harder they are to feed. Any male will be potentially able to draw on the resources of all males in the troupe to care for his offspring, including juvenile males that have yet to attract a mate of their own. So at any time there may be a surplus of available males. As a result there may be a benefit in producing a lot of young while your own siblings and nephews are in their early teens.
The other consideration is that women are by no means helpless. In many climates it is quite possible for HG woman to raise her children single handedly, with males proving just occasional supplements. The only time that women really ‘need’ men is in late pregnancy and early post-partum. That might only be 3-4 months in the child’s entire life. As such provided that a male didn’t get two women pregnant simultaneously there would be no obvious disadvantage to having a dozen females. This has been proposed as one explanation for why women’s menstrual cycles appear to synchronise. By being simultaneously fertile it is almost impossible for two women to become pregnant by the same man at the same time, and much les slikely to occur within the same period.
Of course in other environments you are quite right, a male is essential in raising children and any male with too many kids will see most of them die. The question then becomes whether humans evolved in benevolent environments, or hostile environments, or (more likely IMO) were we always adaptable enough to exploit both.
That probably isn’t an issue. The first thing to realise is that the next tribe is almost certainly closely related to you. In fact since females all leave home the young stud is almost certain to be your cousin or nephew. The chances of random conflict of this type are actually pretty unlikely in HG societies because of these interrelationships. The other point to consider is you are in a tribe, so the young stud would be invading your territory and would be attacked by all the males in your tribe simultaneously. The young stud would need to convince all the men in his tribe to start a war so he could get a mate if he were to have any chance of success. And of course that means convincing your other cousins and nephews to kill you. Very unlikely.
Once again, it probably depends on environment A benevolent environment produces a genetic arms race within the species.
Women certainly stand to benefit if the male remains faithful, although possibly only marginally. But for the male to remain faithful she also has to remain faithful. There is no benefit to him in fidelity if he knows she is cheating. The ideal solution for women is always to find a man with good genes and good child rearing skills. But that is going to be rare because men with good genes can get laid without putting effort into child rearing. So women have choice: the genes or the carer. And in a benevolent environment females aren’t at any great disadvantage if the male doesn’t wok at child rearing. A slight disadvantage to be sure, but not a massive disadvantage. But if the male has lesser genes they are at a large disadvantage. So as a result the best choice in a benevolent environment is for women to eschew the faithful child rearing males and mate exclusively with the males with the best genes. And once that starts occurring the males with the best genes will have even less need to be monogamous and so females will have even les chance of enforcing monogamy. So while it’s certainly always in the female’s interest to have a monogamous partner with ideal genes, if the choice is between genes and monogamy in many cases women will choose genes.
Only in a hostile environment. In a benevolent environment where women can raise children alone it becomes optimal for both sexes to eschew monogamy.
And on a side note, it seems like women may be genetically programmed to opt for polygamy in societies where males won’t commit. Girls who have no males living in the household in a stable relationship enter puberty much earlier (something like 18 months earlier on average IIRC). And they have sex for the first time something like 3 years earlier than average. And they fall pregnant earlier. It’s still controversial but the evidence seems to be mounting that the female body and brain are hardwired to adopt polygamy in societies where men are not monogamous. The theory being that there can be no benefit in waiting to establish long term relationships or emotional maturity so the body shifts into rapid breeding mode and favours gene selection over pair bonding.
That seems to suggest that monogamy is at best a biological option
It would probably be more fruitful to ask whether we are psychologically predisposed to lifelong monogamy.
I’m sure we could find plenty of anecdotal evidence of happily married old couples who have spent their lives together, who are satisfied with their situation and who have nothing to gain in terms of health or happiness by exchanging their spouse either for a new partner or for singleness. This suggests to me that at least some people are “meant” for lifelong monogamy. As for the others, maybe they were not temperamentally suited for lifelong monogamy, or they didn’t find the right partner, or they failed to develop the skills that would make lifelong monogamy a good option.
Whatever is inborn sexual conduct to the human species evolved as an adaptation to a physical environment in which humans have not lived for fifty thousand years or more. Evolution and civilization take place on different time scales. Supposing that we know what is “natural” to human behavior is hiding a value judgment by appealing to an existing prejudice that “natural” is superior to “unnatural.” Of course the absence of rigorous definitions of such terms makes it even easier. Human behavior is guided more thoroughly by social, and emotional adaptation than pure genetic predisposition. It’s hard to hit on a girl by picking lice out of her hair, now days.
People show behaviors that approximate mating behaviors in other species. However, different people, even within the same culture show different behaviors. Some species have very narrow limits of behaviors throughout the species, enforced by the limits necessary to ensure successful mating. Other species are less uniform. Birds, even within small populations show highly variable mating habits, and in some cases that behavior varies over the lifetimes of individuals. Mature female birds of some species tend to mate outside of pair bonds fairly frequently, while younger ones do so far less frequently.
It is of some small interest to note that pair bonding, (the “natural” monogamy so often referred to when speculating about the biological parallel to marriage) does not depend upon mating, fidelity, or even heterosexual alignment in all cases where it occurs. Two male or two female ducks which are together during the time in their lives when pair bonding generally occurs will form such a bond, which then lasts for life. They do not necessarily attempt to mate sexually with each other, and may mate other individuals in rare circumstances. The bonded pair will remain in close association, cooperating in various normal activities throughout their lives. That occurrence usually remains sterile, with respect to the species, of course.
Tris
wow, blake. I would like to see how great posts you make if you are enthusiastic. ;j
The vast majority of known, ancient cultures were polygamous or at least polyamamous. We are sexually dimorphic (suggesting that males continue to have to fight off rivals even after bonding with a woman). And, most interestingly enough, one man’s sperm is actually spermicidal to other men’s sperm (as well as our balls being bigger: delivering more sperm, than relative to bodysize than monogamous primates).
All of that is, I think, pretty decent prima facie evidence that monogamy is certainly not a stable universal in human beings, at least not without some powerful cultural influence to counteract our natures. Our course, “meant” is subjective. But it at least helps to know what the hurdles might be in getting to a particular “meant.”
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This is a little tricky because, while most socieies allow polygamy, the evidence indicates that most family units are not polygamous.
We’re slightly sexually dimorphic, but less so than all the other great apes. If you want to explore the “balls theory”, you have to note that gorillas (true polygamists) have tiny balls compared to ours (and significantly more sexual dimorphism, btw), and that chimps and bonobos have enormous balls (about 10x the size of ours if you adjust for body weight differences). What’s just as likely is that our biology has prepared us to live in a number of different family group situations, depending on the circumstances.
Can you cite where this has been debunked? Frans de Waal features the testes theory prominently in his most recent book “Our Inner Ape”, and he’s one of the leading primatologists in the world. He doesn’t use the theory to demonstrate that humans are naturally polygamous, but only because that data doesn’t indicate that we are, especially in light of the relatively small sexual dimorphism seen in humans.
Previous thread
On testicle size as an indicator of polygamy (note that this thread is using monogamy to mean any single male system, not strictly mongamy):
The first problem is that it fails to address the fact that humans females have none of the signs of fertility found in gorillas or chimpanzees, and that humans have sex more frequently than either species as result, and far more frequently during infertile periods. That alone could account for the difference.
The next problem is that humans are the only bipedal ape. As a result human females tend to ‘leak’ far more than other apes, resulting in greater sperm loss. Once again, that could account for the difference by itself.
The next issue is that gorillas are not clearly more monogamous than humans. Female gorillas routinely cheat and will almost always try to mate with the next-to-senior bull if they have the opportunity to do so undetected. The observed infidelity rate for gorillas is far higher than anything even suggested for any human population. Much less observed. So gorillas should have much larger testicles than humans, yet they don’t.
The next issue is that humans and are carnivorous and live on high energy, low volume diets. Gorillas are almost exclusively vegetarian and live on low energy, high volume diets. Semen contains a lot of protein, it’s not a cheap resource to produce energy wise. Just based on dietary limitation of resource production we would predict that gorillas would produce less sperm than humans or chimps.
Linked to that is the issue of temperature control. High temperature interferes with sperm production requiring larger testes. Humans and chimps are very active creatures, whereas gorillas are fairly sedentary browsers, as a result gorilla testicles shave less heat build up to worry about. That could also account for a discrepancy between the two groups.
Then we come to the problem that humans have abnormally large penises. The size of the penis and testicles seems to be genetically linked to some degree. Human testicles may be large simply because we have large penises.
Next we have to deal with totally different social structures. Gorilla form strong harems ,with one male ‘exclusively’ servicing numerous females. Any male may only be dominant for a short period of his life, or he ,may never become dominant and never have a chance to mate, yet all males have to be ready to mate immediately if the opportunity presents itself. That produces a huge constraint on gorilla testicles because they can’t afford to permanently carry around energy expensive organs that only get used for a few months of their life, but they can’t afford to have small organs because if they do rise to dominance they may be need them for several years. The solution is to come up with a mid-range organ that works reasonably when required, but doesn’t chew vast amounts of energy when not in use. Chimps in contrast have the opportunity to mate continuously, and as a result can afford to gamble on large organs that constantly use energy because they are in constant use. Humans fall into a mid-range situation where human males may not have an opportunity to mate for many years, particularly while young, but due to air bonding may mate regularly once a mate has been found. We adopt a strategy somewhere between a gorilla and a chimpanzee in producing organs that are moderately expensive to maintain but work quite well. IOW we could just as easily explain the difference because human were intended to be exclusively monogamous with no pre-marital sex.
And finally bonobos and chimps are even more closely linked than humans and chimps. Bonobos are even more promiscuous than chimps, yet they have slightly smaller testicles.
Basically the whole hypothesis compares apples and oranges. By including gorillas which are so different from humans it’s throwing carrots in there as well. It’s a hypothesis that doesn’t have an ounce of evidential support beyond the initial observations that led to its construction. I have never even seen one of the proponents of the theory attempt to back it up by looking at the sperm counts of these animals, rather than It contains numerous assumptions, invalid comparisons and logical flaws.
Tyring to use this ‘hypothesis’ to support the idea that humans aren’t monogamous just doesn’t work.
On size dimorphism as an indicator of polygamy:
The problem with this idea is that humans are a strongly sexually dimorphic species. We don’t just differ in body size we also differ in body shape, secondary sexual characteristics, behaviour/psychology, food sources, interaction with young and so on. IOW a human male isn’t just a scaled up version of the human female, he’s a different creature. That makes it very difficult to draw any inferences regarding the meaning of size dimorphism.
To give you some idea what I mean I will show you four birds. The first is the mute swan, in this species the male and female the same size. The next is the Huia where the male is 10% larger than the female. The next is the hornbill where the male is 15% larger than the female. The final is the red jungle fowl, in this species the male is 20% bigger than the female. Which of these species are monogamous and which are polygamous? Based on the information provided we might guess that the mute swan is almost entirely monogamous while the rest of the species become increasingly less monogamous as we progress down the list. So male hornbills should frequently fight with other males for mating rights, female huias should at least occasionally cheat and jungle fowl should be a harem society.
Of course this is mostly bollocks. In reality the mute swan is approximately monogamous, but they are fairly prone to cheating. Male hornbills aren’t at all aggressive and the species is even more monogamous than the swan. Huias are the most monogamous of all the species and the males and females live together constantly so the opportunity virtually never arises for cheating. The only species we got right was the jungle fowl, which does indeed have a single male harem society. So what went wrong? Simple, we didn’t factor in ecological and reproductive dimorphism in our equation.
Male and female swans are physically identical because they live identical lives even to the extent of incubating the eggs and caring for the young. Whatever evolutionary pressures dictate ideal male size also dictate female size.
Yes male hornbills are significantly larger, but not because they fight off rival males. They are larger because they have a reproductive strategy quite different to most birds. The male seals the nesting female up in a hollow branch using mud until the young have fledged. During that whole time the male is exclusively responsible for feeding himself, his mate and the young. He needs to be bigger because he has more demands placed on him to find food.
Huias are even more extremely dimorphic. They have completely different bills. The male bill is short and robust and good for breaking up wood. The female bill is long and thin and good for probing. Huias survived because the male broke up rotten logs and branches and the female then winkled the grubs out of them. The male needed to be larger not to fight off other males but because he had to perform strength related tasks to get food. The female performed primarily dexterity related tasks that required less physical size and strength. The males and females paired up for life and were never seen individually.
So what does all that tell us about humans? Well humans are a species where the evolution of bipedal gait has forced the production of a helpless infant that requires a lot of care and a debilitating birth process for the female. That leaves a time period where the male is almost the exclusive provider for the pair. That is directly analogous to the situation with hornbills, and just as monogamous male hornbills are forced to become larger to take care of a ‘helpless’ mate the same may well be true of humans. Similarly humans hunt high risk prey animals, and frequently suffer serious injury as a result. Moroever bipedal gait and foetal development means that for several months females can’t engage in such hunts effectively or without risking their own lives and the lives of their offspring. Just as huias developed size dimorphism because males and females had evolved to seek different food types this could be the case for humans.
Note that none of this is evidence for monogamy in humans. After all maybe males did get bigger to fight off rivals. But it is just as plausible that males got bigger to provide for helpless mates and young and because the females couldn’t effectively hunt large game. IOW size dimorphism could be equally used as an argument for exclusive monogamy or against it.
You could actually use most of it as prima facie evidence that monogamy is a stable universal in human beings. That’s the problem. the evidence can be used to construct a compelling case either way because humans are so different from all other animals.
Okay, how about the fact that humans aren’t generally monogamous, and appear to never have been such in recorded human history/genetic study, and so on? Isn’t THAT fairly strong evidence that we aren’t biologically monogamous?