The evolution of size matters

I imagine that the process of sexual selection is a different thing today than it was when we were all running around naked. I just can not see the Palaeolithic women complaining about not having enough orgasms. Well, I can see them complaining but would anybody be paying much attention? ") I appreciate that the female orgasm contributes to the likelihood of conceiving but they are not essential and I would think that the male contribution to defence and being able to provide food and shelter would be overwhelmingly more important factors regarding any choices that she might make.I would also question how much input the female would have had regarding her sexual partners 500k yrs ago. I would think that it would have been much less than it is today.Another point about sexual selection is the fact that just about everybody has children. It is not as though only the well endowed do the breeding. I would say that female preference for penis size is a nearly trivial factor in the evolution of penis size.

Yeah that is not one of my preferred tactics either.I am not sure how much we can apply that fact to the behaviour or prehistoric peoples.While I am not saying that women have not always had some say in the matter they are not even considered as equals in much of the world today. How does the catholic church treat them or the Indians or the Arabs? These are examples of relatively stable modern societies and does not consider all of the inter tribal raping and pillaging that went on. I maintain that the 11 or 12 yr old girls who were having their first sex would not have had too much to say about it during the span of time when penis size was developing. I think that the pleasure of sex is simply a driver for fecundity. Women who have more sex have more babies. The sensitivity of the clitoris most likely developed as a result of millennia worth of 14 yr old adolescent excitement and the need to produce an orgasm within 3 minutes of arousal. I am not sure that rape is the right word. Does a dog rape a bitch that is in heat?

No doubt there is lots left to learn even by the people who really know but I wouldn't say that we are naive about it. One area that we ( I ) don't know a lot about is the impact of pheromones on our breeding habits. I would hazard a guess that the way a man smells has a greater impact on his ability to mate than the size of his penis.I guess my biggest objection to the idea of sexual selection is the fact that almost all members of the society become breeding members. I can see it filtering out those that are deformed, incapable or sick but, in the end, if a member is capable of breeding they will likely breed. Sexual selection would only have an impact if the preferred mate was the only one that reproduced.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. It seems unlikely that minor differences in penis length would have that much impact on the entire process.I can see it limiting the extremes as others have said. So if a penis is dysfunctionally small or frighteningly large that would have an effect on the persons ability to reproduce but otherwise I think the impact would be negligible.

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. 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. 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.

Saints preserve us! 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. 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. 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? 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.

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.

Sure they do but I would say that is a recent development. I mean look at any society just 2000 yrs ago. Is there even one that you could point to where the women were treated equally? I am not saying that they didn't have some input. Even a lowly slave girl could twist the will of a king but as a rule I would wager that the men of history have had a lot more say regarding who breeds with who. That is my point that all of the average and smaller men would have been acting on that drive regardless of what the ladies thought about it. As NoNukes said, this is quite an assumption. The preference that the women may have had or have has to actually show up in their choices. If you asked me what my preferred car is I might say a 1979 Porsche 911 in gun metal blue. Even though I could afford it, and assuming my wife would let me buy it, I still find myself with a VW station wagon. My 'preference' is for the Porsche but my choice is the VW.The answer to the question of what a women finds most sexually attractive is not necessarily the same answer to the question of who she would most like to have children with. Even though a preference is identifiable today and even after assuming that it has been ever present it has to manifest itself in the choices made.So I would dispute that " It doesn't matter. As long as it is a preference that preference will show in the evolutionary trajectory." This speaks to my point about other characteristics and how much they were influenced by sexual selection. Why wouldn't we assume that penis size developed along with general physique and it was the other much more important qualities of being able to hunt better or having a disposition for doing the dishes that led to the actual choices that women made.I don't disagree with the sub category of sexual selection as it is really just another element of the environment. I disagree with the amount of overt influence that is being attributed to it in this case. I think the same would apply to the size of a women's breasts. Even if I am initially attracted to a particular sized breast and procreate with that woman simply because of that attraction. If she is not up to the task of rearing children or dies in child birth because her hips are too narrow or is just a down right nasty bitch then I am not likely to have any more children with her. Women with good birthing hips often also have full breasts. Is my attraction to the full breasts or some other recognition of her ability to bear children? The height of a man has a direct correlation to the length of his penis, how do we know that women are not just attracted to tall men? No doubt that our mating choices influence the subtle trajectory of our evolution. Quite a leap to conclude that all of our desirable characteristics are a result of those choices. For example, we find intelligence attractive. Do you think that it has developed as a result of mating choices or because it helps people survive? Or confidence. Self-confidence is a big attractor. Did that develop because women find it attractive or is it attractive because it helps you survive and makes you a better provider?The elements that go into our choice of a mate are staggering in their complexity and number. There are so many easily identified elements that are so much more important for survival and reproductive success that go into one's ideal of a perfect mate.- Infant mortality and short life spans dictate lots of breeding by everyone.
- Men have historically had a greater input regarding choice of mate than women have had thus further reducing any effect of the female's preference.
-Men with unusually large penises are rare and thus dictating that the female's preference would have to manifest itself in a mating choice at a rate that would overcome the mating success of all the average sized men.
-Penis size seems to be related to race as shown by this graph Doesn't this contradict the idea that female preference is a driver for penis dimensions? I don't need my own theory to shoot holes in yours do I?edit; Yes it does.Edited by Prototypical, : No reason given.

I wouldn't say slim but just less than the male input. Haven't males always been the more aggressive of the sexes regarding mating? Are women not more submissive than men are? A women would have to strenuously object as opposed to just being mildly resistant due to a preference for an extra few mm. I wouldn't classify it as rape because of the context although it would classify as rape today. It is more the idea that the male is dominant due to physical characteristics which I think would have played the greatest role as we were developing our social concepts of equality and our sense of empathy.

What kind of an answer is that? Can you point to one society 2000 yrs ago that treated women as equal to men? Where a woman's opinion would be given equal regard. Sure and you need to address the evidence presented. It would also help if you did not exaggerate my position.The evidence is that most of the women in the world today are not treated as equal by most of the men in the world today. That women are achieving more equality as time progresses and they enjoy more equality than they did 2000 yrs ago. I make the assumption that this trend remains true as we go back in time.Men are the more aggressive gender and tend to initiate sexual relations. Men are physically stronger and the urge to mate can be mighty powerful. Restrictions of this urge are of a social nature and are very likely to be more developed now than in the past. No doubt that these restrictions developed as a result of females indicating their wishes but this requires active and determined resistance to the males intentions. The females have always had a say in the matter but they have to work much harder than the male to make it count.These facts reduce the impact of any preference the female might have and or require that the preference be much stronger to have an effect and show up in the form of active resistance. They have everything in common and are both driven by the same process of benefit evaluation. Sure it is a factor but is it substantial enough to have an impact on the evolution of penis size? At the extremes? Absolutely. The repulsion will amount to enthusiastic resistance and the suitor will fail. I can see that it makes a contribution to keeping penis size within it's range. Is that the same as changing it's range of size? Possibly. Except that the logic is not perfect nor is the magnitude of the effect of a woman's preference completely reasonable. I think that my points are valid and have not been refuted.Why aren't all of the penises the perfect size by now?

Eh? The point was that all of the evidence that we have indicates that women enjoy more equality today than they have in the past. That even today, a time when women enjoy a greater amount of respect and equality than at any time in recorded history, they still are not treated equally in much of the world and are, in many cases, unable to express their true desires.I chose 2000 yrs ago because that should be a long enough span to prove the trend. This evidence should offer some indication of a woman's historic ability to express her preferences. From there we extrapolate back into the mists of time and make the assumption that women did not enjoy equal rights 200k yrs ago. Are you suggesting that women's rights have regressed in the last 200k yrs?While we are on the subject of relevant evidence, don't you think that the expressed preference of women today regarding the importance of penis size would be vastly different from the opinion of a woman on the very edge of survival in a harsh environment? A 24 yr old college student does not value the same things that a prehistoric 24 yr old did. I bet you that a good % of all the sex that happened in the world today in places like Saudi Arabia, Pakistan, Afghanistan, India, Rwanda etc would classify as rape if it had happened in the first world. I bet you that rape is a lot less prevalent today than it was 200k yrs ago. I accept that women would object strenuously to mating with a man that had either a giant or a micro penis. I accept that this objection would be strong enough to limit the spread of either case.I do not accept that females are concerned enough with the difference between a 5 and a 6 inch penis when taken in conjunction with all of the other things about a man that dictate her choice of mate to influence penis size beyond the extreme cases. In as much as she would have been able to express that preference. The larger one that all of the women have been supposedly preferring. Which is another point. It isn't as though one size fits all or that all of the women prefer the same thing.

Snort.Because as you say it was prehistoric. Are there some prehistoric teenage diaries that I might refer to?If you look at the evolution of women's rights from 2000 yrs ago until today you can not deny that they have improved. Why wouldn't you assume that this trend would continue further back into eras of which we have no proof?Anyway I think that I have raised some valid objections to the idea of a direct connection between the preferences of modern day 26 yr old Australian gals and the size of my penis...even though I have no objection to any possible direct connection.I also think that I have been thinking about penises way more than I usually do. Lets talk about breast size and big hard nipples.

Odd then that he would make the same type of assumption regarding the linear progression of penis size. The OP study makes the assumption that the preferences of women today have not changed since pre history. I don't know about very poor. Certainly not complete but then who's is?Sure there would be differences and variations between the many small groups and tribes. Some may have been matriarchal (which apparently means that there was sexual equality as opposed to a patriarchal society where there is not sexual equality). However, I think the greater assumption is to think that there was some complete reversal in a trait like male dominance.The advent of agriculture some 10k yrs ago had a profound effect on our social behaviour. I assume that it was at around this time that we began to behave much more like we behave today. Prior to that I assume that our behaviour would have been much more like our primate cousins. I can see how the increase in the stability of resources provided by an agricultural way of life would have completely changed the dynamics involved and led directly to an increase in women's equality. This trend continues today. What I do not see is why it should have led to some whole scale change in the tendency for males to be dominant or why you would assume that they were not dominant before that.Your example of stature is a good example as it demonstrates that environment and nutrition had a greater impact on stature than the sexual attractiveness of a tall man. This supports the idea that not all preferences are strong enough to make an appreciable difference.All of this is in support of my very simple point that a woman's slight preference would not have always shown up in the eventual pairing and that not just any slight preference will be enough to impact an evolutionary track. This chart makes some interesting comparisons between our sexual behaviour and that of other great apes. I don't know how much we can infer from this but I think it is pertinent that the females have fewer partners than the males. It also uses the word 'common' to describe the occurrence of rape in humans (relative to apes I guess).I am not dismissing the idea of sexual selection. It is just that there are so many far more influential elements at work in this case. Like the advantage of depositing sperm closer to the egg when another man's sperm is present. I imagine that an inch matters a lot more to a sperm than it does to a woman.

No it doesn't. It supports the idea that men are taller than women. It also very clearly shows that there are other factors than can easily overpower the effect of sexual selection. This does not mean that there is no sexual selection going on. What evidence supports that idea? WTF man? Are you even paying attention? The alternate theory is that within the framework of evolution some other more important elements are responsible. I see now that there is a word for what I have been talking about. Pleiotropy.So, for example, if I have a high level of intelligence and this allows me to successfully woo a female into submission (see what I said there) with elegant speech and humour and leads to my reproductive success you might say that my intelligence was sexually selected for. In reality my intelligence played a much more important role in my survival up to the point where I was able to reproduce than it did in my securing a mate. So even though there is sexual selection going on it is not the primary driver of the development of intelligence.

Yeah I understand that but it is being posited to explain general penis size. This is the same type of issue. Men are taller for other biological or beneficial reasons beside being attractive to women. They are attractive because they are taller not taller because they are attractive. A bit of a chicken and egg thing but it seems that it would be the survival advantages of a trait that make them attractive.I mean if height was a disadvantage in hunting and defence would it still be an attractive feature? The same applies to penises and what makes them attractive or not. (Not for hunting or defence, you meathead, but for making babies.) Differences between the haves and the have-nots are not differences in sexual equality. Those in high society are just like those down at the bottom with the exception that they are generally more depraved and susceptible to power tripping. Men and women both.I am sure that it was all very complicated but a trait like male dominance does not show up or disappear quickly. It is slowly being minimized by social pressure and the rejection of violence as an acceptable thing.

I thought that sexual selection was primarily evidenced by the existence of otherwise useless or even counter productive features like bright colours on birds. Obviously, the penis is neither useless nor counter productive and a little extra size has proven benefits.It is interesting because sexual selection could be said to be conscious interference with the path of evolution even if they didn't actually know what they were doing. Almost like a boost in the speed of evolution or some kind of direction apart from that dictated by the environment. That is if we can consider ourselves to be separate from the environment.It also begs the question of why we desire what we desire and if there is anything at all beside what makes more babies.