The size of the testes of human males suggest that human females are relatively monogamous.
They are closer to those of Gorillas than those of the Chimps.
This suggests to me reduced sperm competition in humans. Human females on the other hand don't have a clear physical indicator to give insight into male monogamy. anecdotal accounts say less so. Although some studies suggest male cheat is on par with female infidelity. Historically there have been more polygamous cultures than monogamous ones. (for what that is worth.)
Testes size indicates that we are between the chimpanzee and gorilla - not closer to the gorilla. In fact, in terms of testes size to body size ratio we are closer to the chimp; gorillas have almost no testicles. I agree with you that sperm competition was reduced in our lineage - however, understanding the degree to which it was reduced is difficult. To me, our testicle size indicates that we evolved in a system where a minority of men had the ability to practice polygyny, with other males defaulting to monogamy (with infidelity) and/or serial monogamy.
If the ratio of the testicle size to the size of the female (the most thoughtful metric as sexual dimorphism can be the cause of small equipment) is used we are much closer to Orangutans than anything else. (pan and gorilla are at freakish extremes) And as everyone knows they are bigamists (and in some instances rapists) human female fidelity and male promiscuity is the received wisdom. But if I remember right american male cheating is about 30% and female 15% and non- paternity is about 10% (I don't have the study in front of me.) Non-paternity in "mates for life species" tends to be around 30%. So humans are near saints when it comes to things sexual.
My guess is that without the strident scarlet-letter that accompanies cheating, most adult males would go the route of the gibbon. If it were socially acceptable all us gibbon males would be spreading our gibbon seed all over creation. So what exactly is monogamy giving us from an evolutionary advantage? Apparently not enough to actually be monogamous or we wouldn't have that word flexibility have to be put in there.
So what exactly is monogamy giving us from an evolutionary advantage? Apparently not enough to actually be monogamous or we wouldn't have that word flexibility have to be put in there.
I have never understood monogamy from an evolutionary or practical or emotional point of view. It makes no sense to me. I can understand finding a partner you prefer and not wanting to complicate your life with multiple partners. Who has the time? But when I see words like "cheating" - I say, "What's your deal? Was your deal spelled out? Did you let your deal evolve? It sounds like you need a different deal or more openness." I understand monogamy only from a psychological point of view. Insecure people insist on monogamy as way to hopefully or mutually control their partners. Anyway, I realize my opinion on monogamy is not a popular one. I imagine monogamy makes sense to some people. Promiscuous is a word used by people who don't like sex to put down those that do. theadvancedapes Do non-monogamous apes say, "Will you still respect me in the morning?" Do apes ever feel used? Anyway, good post.
From an evolutionary perspective, it probably evolved as a by-product of social monogamy. From a practical perspective, it makes a ton of sense for ecological/economical points of view. For men its usually practical because male-male competition for fecund mates is very high. For women it made sense in the Paleolithic because they could increase the probability of bi-parental investment (it is another debate about what sense it makes for women today in the developed world). From an emotional perspective, that is a personal opinion that everyone should be free to make on their own. I personally like the idea of finding someone that I can bond with long-term. However, IMO whatever someone feels comfortable with should be acceptable (as long as they are not purposefully hurting other people). Many people unfortunately do this, however this is not how monogamy is practiced at its best. Monogamy can also be developed from a psychologically healthy place - not always from insecurity. Well, as I said above, I think you need culture to truly be sexually monogamous. Biological evolution would never really favour sexual monogamy so it is hard to say. However, studies have shown that gibbons become exceptionally depressed when their partner dies. This is probably because they formed a strong emotional bond with that partner (they share songs, feeding rituals, defend each other from predators and raise young together). They may not care about sexual extra-pair copulations. Males have not been observed to mate guard, but that may be because both partners sneak extra-pair copulations fairly well. Not sure if this answers either of your questions... I don't know how we would know whether great apes felt used. I'm guessing that they experience a range of sexual emotions that are dependent on the context of their socio-sexual system.I have never understood monogamy from an evolutionary or practical or emotional point of view.
Insecure people insist on monogamy as way to hopefully or mutually control their partners
Do non-monogamous apes say, "Will you still respect me in the morning?" Do apes ever feel used?
It makes me sad to think of depressed gibbons. Dogs certainly become depressed when an owner dies. (You've talked about animal emotions in several places in your blog.) Monogamy can also be developed from a psychologically healthy place
Absolutely - In a lot of cases, exclusivity has been openly discussed and agreed upon. It's certainly an easier way to run a life.
It can be easy and psychologically rewarding - even fun! But I definitely understand your perspectives on this topic. Any monogamous relationship that is founded on insecurity or notions of ownership will probably be destructive.
"A man is basically as faithful as his options"
-Chris Rock For the most part, this seems about right. If a man wants to remain monogamous, the key is to avoid situations that would cause "indiscretion". Finding someone you "prefer" is a starting point. If you want a healthy monogamous relationship, they also have to be someone you trust. Jealousy is an ugly, ugly thing. Loved your comment Lil.
From further research I have come to believe that sexual monogamy could not be selected for by any mechanism of biological evolution. Sexual monogamy is a by-product of selection for social monogamy (which has many evolutionary benefits). So I actually think your comparison to gibbons is fairly sound. However, it is important to note that culture can be so powerful as to make people truly monogamous.
After reading this I wonder if monogamy is more or less prevalent in Western societies that based increasingly on information services and communications technology, not to mention a wage system as opposed to a pure agrarian lifestyle as mentioned in the article. I just feel there is less and less to tie down people to each other in today's society, short of having a child.