Young women are more attractive because, through evolutionary selection, men find fertile women more attractive. Genes which caused men to find unfertile women more attractive quickly died out.
Sure, its possible or even likely that evolution has something to do with it, but i think you need a more compelling evidence than that to be convincing.
Human children takes over a decade to become adults, so it is pretty likely evolution selected for women who stopped getting pregnant once they neared the end of their lifespan. Producing kids is super expensive so better take care of those you already have at that point.
> Why is the sterotype that youth is very attractive in woman, but the same sterotype doesn't apply to the same extent in men
Reasonable theory: Women mostly select men with good genes. Men mostly select women who can get pregnant and survive said pregnancy and bring the kid to adult. The main predictors for a woman being able to get and survive pregnancy is that she has a flat stomach (so not already pregnant) and she is young and healthy. Also existing kids will hurt your kids so better select a woman who doesn't already have kids, which historically meant young women.
Good genes is much more complicated, age is a positive factor here since it means the man could survive for that long but there are all sort of things women could look for here.
Would love to hear your proposed mechanism
You could argue that it would be better if the genes considered these scenarios better and adapted. But genes are very crude, they can't encode for all those things, so instead they just do what is best in the typical scneario.
Additionally, in pre-industrial societies, i think that children become a net positive much quicker, so im not sure the resource calculation is quite as stark.
E.g. compare societal attitudes: more blacks shot by police => definitely racism => massive protests; more men shot by police => well obviously men are biologically wired to be more violent.
I assume because women’s fertility is pretty much gone by the time they hit 40, while men are fertile till past 100 years old.
Do they? How can they tell? Do they ask to see the eggs first?
> Genes which caused men to find unfertile women more attractive quickly died out.
Die out? I don't think genes work that way. But maybe language is a stumbling block here.
I will grant you that fertile women have been fertilized historically because tada - here we all are! But that does not in any way mean that all sex was for the sake of fertilization. Or even between semen- and egg-bearing people. And the amount of non-child-producing sex both today and historically seems to suggest that fertility is not the primary concern, let alone cause for non-childbearing sexual urges to "die out."
Men who only sought sex with other men* or with postmenopausal women may have had a lot of sex, as you say, but they also have no descendants (unless a fertile woman raped them at some point, or they were born late enough to donate to a sperm bank). So their genes died out. Even a fairly small inclination in this direction is enough to produce a very large difference in gene prevalence after many generations. In only 200 generations, an allele that gives you an only 5% lower chance of having children will decrease in its relative prevalence by a factor of thirty thousand (0.95 ** 200 = 3.5e-5). That is the way genes work.
Of course most sex among humans (and hominins in general) doesn't produce offspring, and in humans and bonobos (but not chimpanzees) most of it can't possibly produce offspring. That's fine. Sex isn't a limited commodity. Sex is abundant. But hominins, especially humans, are choosy about who they have sex with, and any alleles that can get them to be choosy in a way that will increase their chances of reproducing will become more abundant over time.
Is 200 generations a long time? Hominins are about 300,000 generations old. Australopithecines are about 200,000 gnerations old. Homo is about 100,000 generations old. Homo sapiens is about 10,000 generations old. Agriculture and Catal Hoyuk are about 500 generations old. So I don't think it is.
Does that help?
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* Unless those other men they were having sex with were trans men equipped with a fertile uterus, anyway.
Edit: of course not. I'm just pointing out the conclusion coming out of this:
>Men who only sought sex with other men [...] have no descendants (unless a fertile woman raped them at some point [...]). So their genes died out
Women rape men fairly rarely, and even a woman who raped thousands of men generally cannot have more than a dozen offspring as a result. By contrast, one in every 200 men today has Genghis Khan's Y chromosome: https://en.wikipedia.org/wiki/Descent_from_Genghis_Khan
This should go without saying, but I'll say it anyway: the fact that rape can produce offspring does not make rape morally commendable or tolerable.
It's true that the stubborn existence of gay people poses challenges to any kind of simple ev-psych explanation of human sexuality, and it's tempting to conclude that although sexual behavior in sheep and partridges is instinctual, sexual behavior in humans is purely culturally constructed, because humans are rational beings not controlled by instinct, and this is why some humans are gay. This explanation runs into several big problems:
1. Lots of sheep and partridges are also homosexual. Also several hundred other species at least.
2. If you have ever met a human, you know they are not very rational, and cultural conditioning is in a constant pitched battle with human instincts.
3. For decades in the US the standard treatment of male babies born with deformed genitalia was to perform sex-reassignment surgery on them and raise them as girls. If human sexual behavior were purely culturally constructed, then as adults about 90% of them would have sought male partners, like 90% of other children raised as girls. Instead, most of them sought female partners.
4. Homosexuality seems to be a cultural universal.
So, the evidence in favor of the "born this way" hypothesis is pretty overwhelming, especially for men. So, how did "gay genes" not get wiped out?
Among the numerous theories mentioned in the WP article: "There was genetic material being passed down on the X chromosome which both promotes fertility in the mother and homosexuality in her male offspring." (Camperio-Ciani, Corna, and Capiluppi 2004) Another possibility is that being gay is biological and congenital, just not genetic, for example due to fetal hormone exposure or immune response by the mother's body.
Historically, lots of gay men have been voluntarily married to women, had sex with them, and had children with them. This still happens today. I have known gay men who have never had sex with women, but they are very much the exception to the rule. (There are men who are exclusively attracted to postmenopausal women, too, just not very many of them.)
I mean, boys with just four older brothers are also growing up in a pretty different environment from firstborn boys or boys with just four older sisters. Just because this would be precisely the opposite environmental effect that conventional postnatal environmental theories of homosexuality predict doesn't mean there's no postnatal environmental effect.
This isn’t at all the case these days. And anyway, it’s also quite common for straight men to have had gay experiences.
Gay sexuality remains a puzzle from a narrow evolutionary point of view. None of the theories that have been proposed is really very plausible. As a gay man it is honestly quite amusing to see all of the bizarre alleged ‘explanations’ that people come up with. Especially since these always seem to be implicitly focused on male homosexuality - not because it’s any more in need of an explanation than any other kind of sexual behavior, but because it freaks people out.
All research in this area seems to pose the basic question as follows: “Well obviously straight people exist, but what could possibly be the explanation for all these aberrant cases?”. It fails to recognize that procreation is just one function of sex. It’s like being surprised that people use their mouths for kissing as well as for eating and talking.
A equally big puzzle is all the non-procreative sex that straight people have. That one doesn't get much research attention though, because straight people aren't considered to be an aberrant case.
On evolutionary timescales, anything that doesn’t help procreation will die out. Simple as that.
I mentioned this in my previous comment: "Most sex among humans (and hominins in general) doesn't produce offspring, ... That's fine. Sex isn't a limited commodity. Sex is abundant."
I think this aspect of human sexuality does get a lot of attention in research; I mean, it's absolutely central to human reproductive behavior. Concealed ovulation, menstruation, extraordinarily high male parental investment for a mammal, extended female sexuality, female copulatory vocalization combined with monogamy, monogamy combined with substantial sexual dimorphism: human sexuality is weird, and every aspect of that sexual weirdness is profoundly connected to non-procreative sex. I mean, we're weird in lots of ways, but sexually speaking, we're total freaks. We're so strange we're practically birds. Except for the sexual dimorphism thing. Even mallards aren't that weird.
And it's wonderful! But very puzzling.
> It fails to recognize that procreation is just one function of sex. It’s like being surprised that people use their mouths for kissing as well as for eating and talking.
The puzzle is not that some organisms engage in non-procreative sex, though; that's a lot more common than bizarre phenomena like mammalian monogamy or concealed ovulation. It's that some organisms, especially males, voluntarily refrain from procreation. There aren't a lot of organisms where that happens: sheep are one example. From an evolutionary point of view, it's a real challenge to explain how instincts for such behavior could be conserved.
The whole naturalistic fallacy you allude to, along with all the Catholic peccatam contra naturam nonsense, definitely contributes to the confusion.
> male homosexuality - not because it’s any more in need of an explanation than any other kind of sexual behavior
It is, though. Female bedbugs, like female organisms of many species, can reproduce without ever voluntarily copulating. (Bedbug penises are the stuff of nightmares.) Even in a species where copulation is 100% voluntary, female homosexuality has to reach a pretty high level before it starts to diminish ω, especially in a high-parental-investment species; you could imagine an elephant species where cows frequently mount other cows and perform oral sex on them* every day, but only have sex with bulls three times per estrus, and only go into estrus every five years. So in every five-year interbirth interval, cows of our hypothetical elephant species would have sex with other cows some 1500 times and bulls three times. The females of this hypothetical species would be 99.8% homosexual. But they'd have just as many offspring as cow elephants of actually existing elephant species.
More to the point, in this hypothetical elephant species, a less-lesbian mutation that caused a cow to copulate with bulls ten times per estrus instead of three times would increase her number of offspring only very marginally, if at all: in the cases where the first three copulations failed to produce offspring, she'd save herself an estrus.
By contrast, a 99.8% homosexual bull elephant would have... a lot less offspring than a regular bull elephant, as long as there's an occasional Casanova bull running around engaging in extra-pair copulation. Not 99.8% less offspring, because there aren't that many cow elephants around (there's no possibility of a Genghis Khan elephant), and elephants practice mate guarding. But a lot less. Maybe 50% less. And being even a little more heterosexual would increase his ω a lot.
So, aside from the knuckle-dragging Victorian factor, there are also totally legitimate ev-bio reasons that exclusive male homosexuality is surprising and challenges naive ev-psych theories more than exclusive female homosexuality.
> None of the theories that have been proposed is really very plausible.
Agreed.
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* Lesbian elephant trunk sex is totally a thing in real life, just not as prevalent as in this scenario.
Evolutionary theory has contributed approximately zip to our understanding of human sexuality. But it sure has contributed many volumes to the literature on it. Sadly, much of the allegedly scientific literature on homosexuality just rewords Catholic doctrine on the subject in the language of pop evolutionary psychology.
Agreed.
> There are more things in heaven and Earth than are dreamt of in your philosophy.
Yup. I'm a lot more confident that gay people exist than that ghosts exist, though :)
> Gay people are pretty used by now to being told that we don’t “fit in” to some overarching theory of nature that’s currently orthodox.
Agreed. It's tiresome.
> Evolutionary theory has contributed approximately zip to our understanding of human sexuality.
That's a point where I disagree, though I think most of what it's contributed is negative: debunking all kinds of wishful thinking on the part of neo-Victorians and Catholics.
> By all means continue to be puzzled that reproduction doesn’t explain every aspect of human behavior.
I don't plan to start being puzzled about that. Maybe you intended to post your comment on a different thread?
What would really be convenient would be for me to not say anything in public, ever, that could be taken out of context as condoning rape.
First its missing the specialization pressure. In a finite habitat, any species not afflicted by disease or predators, bumps repeatedly against the resource-roof in cycles of strife. Evolution, being the dumb, process it is, optimizes for that. So you get, within every population, neuro-subspecies that are heavily adapted to situations in this spiral.
Some of these subspecies actually behave like you predict, because their environment is to unstable and longterm planning is a disadvantage, when your risk seeking behaviour makes you jump on a mammoth with a spear tomorrow.
For others, who thrive in the more peaceful environment (post-conflict/diseases/disaster curve falling back into the habitable zone) they might benefit largely from producing societal byproducts.
"Sexual-Deviants" which your post designated as a die out, have valuable properties for a society. They can form a third "power-pillar" upholding contracts between the different interests of "pump&dump" and "I-need-longterm-commitment".
Now, this gives us something, called prediction power. And with it, we can predict, that hating non-heteros makes you a more useful creature for the females of the species, who then can choose you as mate and force you to go into the current active social-contract-cult, which will force you to commit.
This "law-producing" biology is so useful, it out-competes the simple biology model, were it not for the resources running out, due to exponential hunger.
I hope we are all grown ups here, who can talk about differences and issues, without freaking out.
The whole topic gets really cool, when you start assembling social machinery from the different neuro-subspecies.
I don't approve of a person being forced into a culture or lifestyle for his/her sexuality, no matter how much that culture claims to benefit him/her. People should be allowed to transcend biological limitations completely.
I arrived at this model, mainly because the classic evolutionary models couldn't predict alot of things and behaviours i observed in my family, peer group and society.
In my model, you can point to the top of the spiral, and predict, that evolution will produce a creature that has no empathy for anyone, except for the group that produced it. And this creature will try to drag the whole of society into a warlike state. And then you look at the world, and you see them.
Sorry if such looking into our nature makes is a insult to you, but i think knowing is always more helpful.
They can't tell. They are just attracted to women who look a certain way. They are attracted to women who look that way because they are descended from men who were attracted to women that looked that way.
It's similar to the old story about how giraffes got long necks so they could reach higher leaves in the tree. Giraffes don't look at each other and think "wow, he can reach a lot of leaves!" They look and think "wow, he's got a long neck!" Why are they attracted to long necks? Because they are descended from giraffes who were attracted to giraffes with long necks, and those giraffes were, on average, more successful at getting leaves from trees.