Sexual selection would only have an impact if the preferred mate was the only one that reproduced.
Of course. And if the preferred mates are statistically those with larger members, then the tendency will be for the population to evolve larger members on its men. Over time, the entire population would have statistically larger-membered men even to the point, perhaps, that no male would have a member as small as any male in the original ancestor populationdeformities aside.
It seems unlikely that minor differences in penis length would have that much impact on the entire process.
In what way? So-called 'minor differences' are what evolution is all about.
Then there is the fact that there are many elements that make up the preferences. So eye colour, height, strength, intelligence, demeanour , generosity and kindness would all go into the mix.
There are other sexual characteristics in humans that are also unusually evolved; it's not just penises.
Of course. And if the preferred mates are statistically those with larger members, then the tendency will be for the population to evolve larger members on its men.
I think that you missed my point.
There are 100 males capable of breeding in a population. 50 of them are average, 25 are small and 25 are large. All of them reproduce because there are 100 females who want a mate and so the average size is not changed. It is not as though only the larger males get to do the breeding or that a larger penis makes you more virile.
In what way? So-called 'minor differences' are what evolution is all about.
Sure but my point is that the minor differences in penis length have no mechanism to accumulate. Even if the females prefer a slightly larger penis this does not impact those with smaller penises because almost everybody breeds. It is not as though the females are lining up to mate with only the larger males. It may be that those with a larger penis get the first choice but they are not the only ones who are getting some. So it seems like it would be a wash.
There are other sexual characteristics in humans that are also unusually evolved; it's not just penises.
But which ones were directed by the preferences of the humans involved. I may prefer a woman with cantaloupe sized breasts but this does not mean that I would refuse to breed with a woman strictly because their breasts were smaller or larger. I would think that the preference has to be strong enough to exclude someone from breeding based on that preference alone in order for it to make a difference in the evolution of that trait.
I take it, then, that you reject sexual selection altogether? It occurs to me that you are applying our current sexual context to our evolutionary history. On what grounds do you conclude that "everyone breeds" applied to our ancestors 100,000 years ago or 1,000,000 years ago?
And how else would you explain Homo sapiens' dramatic secondary sex characteristics? Our sexual dimorphism, in size and shape (if I recall correctly) exceeds that of our primate cousins. What is the origin of the male wedge (broad shoulders/narrow hips) and the female hourglass?
You seem to be arguing that a trait must be subjected to absolute selection to make an evolutionary difference. But modern era studies of evolution in action--from the beak sizes of Darwin's finches to the survival advantage that tree swallows with just a few mm shorter wings enjoy (thus reducing road kill incidents)--contradict you. If your argument for an absolute effect from sexual selection were valid, I don't see why it wouldn't apply to selection in general.
Have you refuted selection altogether?
I wouldn't argue that a female preference for a larger penis strongly influences reproductive success now, but rather than it once did. So a surviving preference is exactly what I would expect, just as our preference for calorie-rich fat survives, although it does not serve us well now.
Edited by Omnivorous, : too many millions
"If you can keep your head while those around you are losing theirs, you can collect a lot of heads."
There are 100 males capable of breeding in a population. 50 of them are average, 25 are small and 25 are large. All of them reproduce because there are 100 females who want a mate and so the average size is not changed. It is not as though only the larger males get to do the breeding or that a larger penis makes you more virile.
It's not about whether you reproduce or not but about how many times you reproduce.
Assuming everyone's penis size is easily determined (folks are naked, for example), a man with a larger penis will mate more than a man with a smaller penis. The man with the larger penis will have more females who are interested in him (because females prefer his larger member) while the man with the smaller penis will have fewer females who are interested in him (because they mostly prefer the other guy's larger member).
This difference in reproduction frequency is all it takes to create changes in the whole population, especially when the changes are really minor like the size of the penis.
It may be that those with a larger penis get the first choice but they are not the only ones who are getting some.
No, but they are getting more.
I may prefer a woman with cantaloupe sized breasts but this does not mean that I would refuse to breed with a woman strictly because their breasts were smaller or larger.
Even selection pressures that are nothing more than a preference are enough to direct evolution down one path as opposed to another. Your belief on how strong those preferences have to be doesn't hold up; even a slight preference for a particular trait is enough to evolve toward possession of that trait given enough time.
Assuming everyone's penis size is easily determined (folks are naked, for example), a man with a larger penis will mate more than a man with a smaller penis. The man with the larger penis will have more females who are interested in him (because females prefer his larger member) while the man with the smaller penis will have fewer females who are interested in him (because they mostly prefer the other guy's larger member).
Are you speaking from experience? How many kids do you have?
I'm speaking from the study linked in the OP. If women prefer larger penises, then men with larger penises will get more female attention.
How many kids do you have?
None, but life in 21st century civilized America is far from comparable to the societal, environmental, and cultural conditions of our earliest ancestorsthose in whom larger penis size first began being selected for.
Assuming everyone's penis size is easily determined (folks are naked, for example), a man with a larger penis will mate more than a man with a smaller penis. The man with the larger penis will have more females who are interested in him.
Would not this imply that women are incredibly stupid and think strictly with their genitals? Surely at least one or two women might notice that Caveman "5 cm" is taller, stronger, and more able to bring home more meat to the cave than Caveman J. Holmes.
Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I would say here something that was heard from an ecclesiastic of the most eminent degree; ‘That the intention of the Holy Ghost is to teach us how one goes to heaven, not how the heaven goes.’ Galileo Galilei 1615.
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
Would not this imply that women are incredibly stupid and think strictly with their genitals? Surely at least one or two women might notice that Caveman "5 cm" is taller, stronger, and more able to bring home more meat to the cave than Caveman J. Holmes.
No one has said that nothing else goes into the decision process. In fact, the page linked to in the OP clearly discusses some other physical factors that affect attractiveness.
However, penis size is clearly one of the factors, likely more weighted than some other factors and likely less weighted than some others. Whatever the case, it is a factor; and this is what makes it susceptible to sexual selection.
I take it, then, that you reject sexual selection altogether?
Saints preserve us!
On what grounds do you conclude that "everyone breeds" applied to our ancestors 100,000 years ago or 1,000,000 years ago?
That is a good question and I have considered it for a while. My answer is 'Are you kidding me?' People are almost like Bonobos. Don't you remember being a teenager?
I certainly can not give you an educated answer but what would lead you to think that it wouldn't apply? I think that historical rates of infant mortality alone would necessitate that everyone did lots of breeding in order for our population to grow as it did. Are you suggesting some type of hierarchical arrangement where only some of the capable members were allowed to breed and that this was successfully enforced? This would certainly amplify any preference shown by the breeders.
I guess that I can not exclude that possibility but it seems unlikely to me that our basic sex drives would have changed that much. Most, if not all, of the restriction of our sex drive is of a social nature. If anything I would think that our impulses would have been subject to far fewer restrictions in aeons past but you are right to point out that I have no way of knowing. I think that the same caveat would apply to the assumption that the preferences of prehistoric women would be consistent with those of women today.
And how else would you explain Homo sapiens' dramatic secondary sex characteristics?
Form follows function. Just look at a female body builder.
I am not dismissing sexual selection all together. It just strikes me as a leap to infer that it is the cause of the state of some physical characteristic. What about eye colour or the shape of your ears? How do we determine the amount of sexual preference that went into the development of those characteristics? Penises are a certain size because they need to be a certain size in order to function. Too small is no good and too big is no good. These are physical limitations and have nothing to do with preference.
You seem to be arguing that a trait must be subjected to absolute selection to make an evolutionary difference. But modern era studies of evolution in action--from the beak sizes of Darwin's finches to the survival advantage that tree swallows with just a few mm shorter wings enjoy (thus reducing road kill incidents)--contradict you.
I am not disputing that small differences can be critical for survival. If you have this minor difference then you survive long enough to breed where others do not. Penises are not like that. My penis may have made my life worth living but I can't say that it has ever saved my life.
I am not sure about your distinction regarding absolute selection. I see that a trait is either beneficial to your ability to reproduce or it is not. Either a selection is made or it is not. Jon raises a good point about the frequency of mating and the subtlety of evolution. That if all of the larger men throughout evolutionary history have sired 1.1 children for every 1 child sired by an average male then that would be enough to increase the prevalence of the trait. I do not disagree with that however the fact that the larger than average male is just that and not average would mean that they would have to do a substantially greater amount of breeding to impact the population at large given that there are not that many of them.
I am doubting the inference that the females preference for a slightly larger penis is strong enough or exclusive enough to actually have made that difference. I am saying that the other elements that make up a woman's choice of mate like the ability to provide food and protection would overwhelm any preference for penis size.
Could we verify this theory by showing that the women in countries like Sudan have a much stronger preference for larger men than women in other countries? Going by the map up thread can we determine that Chinese and Indonesian women do not prefer a larger penis?
Have you refuted selection altogether?
Bite your tongue. I am just saying that a selection factor has to pass some threshold in order to actually make a difference and I am doubting if this one does that. The preference may be there but is not exclusive enough to make a difference.
This difference in reproduction frequency is all it takes to create changes in the whole population, especially when the changes are really minor like the size of the penis.
I agree that a subtle difference in reproductive frequency could eventually make a difference. I wonder if the subtle preference for a slightly larger penis would equate to an increase in reproductive frequency. We have to assume that the female could enforce the preference to a degree that would over come the average male's drive to breed. I question to what extent the women of history have had this ability.
How many women in the world today are able to express their preference for a particular mate? Even for the ones that can how many would be basing their preference on penis size? I just think that the preference would be dwarfed into complete insignificance by factors like general health or physique or wealth or status.
I would concede that I am likely underestimating the potential effect of an extremely minor selection pressure. On the other hand I think that such small pressures would be negated by other far more critical selection pressures.
Now days there are dating sites. Woman and men can both sit back in the comfort of they're home and select those they find attractive.
Nowhere on these site do I see a block that request you indicate the size of your John Thomas.
I do think it would be a interesting study to interview those who did eventually copulate as what the intital decisive factor was.
I believe it is facial symmetry and indicators of good health. The penis size does not enter in to it. ha ha. pun intended.
However I do agree with Rox, there has to be something to work with.
Edited by 1.61803, : No reason given.
Edited by 1.61803, : removed redundancy.
"You were not there for the beginning. You will not be there for the end. Your knowledge of what is going on can only be superficial and relative" William S. Burroughs
No one has said that nothing else goes into the decision process. In fact, the page linked to in the OP clearly discusses some other physical factors that affect attractiveness.
It seems you did say exactly that. Yeah the OP does include other factors, but then you did not write the OP, did you?
Assuming everyone's penis size is easily determined (folks are naked, for example), a man with a larger penis will mate more than a man with a smaller penis.
Pretty unequivocable statement there.
Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)
I would say here something that was heard from an ecclesiastic of the most eminent degree; ‘That the intention of the Holy Ghost is to teach us how one goes to heaven, not how the heaven goes.’ Galileo Galilei 1615.
If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
™ Version 4.2
