Surely masturbation=males evolving to age faster=shorter life spans? [Answered - No]

[Dom203]

I was just reading this article:

http://frostfirefizz.com/why-males-die-before-females

 

And suddenly realised this:

Since apparently our brains are quite primitive, that means that our bodies can't tell the difference between mastubation and sex, right?

 

Well if this is so, then if you masturbate from a young age, your body would assume you were having sex, and therefore having kids very early on, meaning you're not needed much after that - you've reproduced!

Since (I gathered from that article - kindof ) you're not really needed (as far as genetics are concerned) meaning your genetics will program future generations to age faster since it assumes they'll reproduce from a young age!

 

 

Could someone point out flaws, tell me if they agree, share thoughts etc?

 

Thanks

 

 

PS I suppose that would mean that in the future, people (mainly males) will go through puberty at a much younger age?

[insane_alien]

well, evolution kind of favours those who propagate their genetic code more than other individuals so the purpose would still be long life. there is no biological clock saying you die so many years after you have sex.

 

masturbation does not have any observed negative effects(appart from maybe spending more time in the bathroom or wherever your favourite spot is).

 

anyway, wouldn't this also mean that people who have kids really really early(but don't masturbate, crazy scenarios i know.) on have much shorter lifes as well?

[Dom203]

anyway, wouldn't this also mean that people who have kids really really early(but don't masturbate, crazy scenarios i know.) on have much shorter lifes as well?

 

Well I'm not saying immediate effects, I mean "wouldn't it result in shorter lifespans for males in several generations' time?" - so it would have 0 IMMEDIATE effects, but genetics would change to "accomodate" for "having sex early on"...

[insane_alien]

why would the genetics change? i don't believe masturbation is mutagenic or induces any selection pressures either way. i'm pretty sure humans have been spanking the monkey for many thousands of years and our lifespans have only gotten longer.

 

okay, so i just read the article there. it doesn't actually mention anything about masturbation at all. it just says that in polygynous species the males appear to be more short lived than females. there are many many factors that could influence this. not just how many times they've ejaculated. especially since they would tend to get into fights more often which canshorten the average life span especially if those fights are to the death.

 

seeing as masturbation doesn't requie competition(it only takes one) and humans are monogamus(for the most part) it should be that male and female lifespans are similar. i think the fact that males tendto be involved in manual labour more often has more to do with this than how often you've masturbated.

 

and you also seem to be forgetting that women masturbate as well which according to you should lower their life expectancy as well again leading to similar life expectancies.

[CDarwin]

Well I'm not saying immediate effects, I mean "wouldn't it result in shorter lifespans for males in several generations' time?" - so it would have 0 IMMEDIATE effects, but genetics would change to "accomodate" for "having sex early on"...

 

You're thinking like a Lamarckian. With minimal exceptions, the actions you take in your lifetime don't effect what you pass on to your offspring, and it is that that is evolutionarily relevant.

 

We're not even mentioning the fact that masturbation and sex are quite different things, behaviorally and physiologically, and animals that do them tend to do the two for different reasons. Masturbation is most commonly a stress-relief device, where-as sex is obviously geared toward reproduction, and it involves a host of chemical and behavioral signals from the female that affect the male physiologically.

 

Nor are we mentioning the fact that females of most species masturbate too.

[ecoli]

I was just reading this article:

http://frostfirefizz.com/why-males-die-before-females

 

And suddenly realised this:

Since apparently our brains are quite primitive, that means that our bodies can't tell the difference between mastubation and sex, right

I'm not sure there's any scientific basis to this assumption.

 

Well if this is so, then if you masturbate from a young age, your body would assume you were having sex, and therefore having kids very early on, meaning you're not needed much after that - you've reproduced!

You can also look at it from a different perspective... Young people are not as emotionally or intellectually fit to raise children as an older person. So, even if a child is biologically ready to have a child at an age of 12, how can someone so young raise a child? Perhaps masturbation is a tool that is used delay the onset of reproductivity, so you don't have to take care of babies until the person is mature enough to handle it. Masturbation, of course satisfies sexual desire without actually reproducing.

 

Of course, this doesn't answer the question, why didn't evolution just delay sexual maturation. Why does sexual maturation come before emotion maturation? Perhaps there are biological reasons why sexual maturation must come first.

So, instead of changing these biological processes, it was more parsimonious for evolution to 'invent' masturbation, as in, it was required less time and energy to come up with that solution, and thus was favored.

 

sorry for the teleological reductionism

[John Cuthber]

Evolution only acts in response to how many children you have. What you do before that cannot malke any difference.

Incidentally masturbation is pretty common amongst animals so it's a safe bet we were doing it before we were human.

[iNow]

why didn't evolution just delay sexual maturation. Why does sexual maturation come before emotion maturation? Perhaps there are biological reasons why sexual maturation must come first.

The younger a life form is when it can begin reproducing, the more offspring it can have over it's lifetime. If boys and girls had to wait until they were 20 to start having children (during a time when average lifespan was 30), then they'd have very few offspring. However, if they can start reproducing at 11 or 12, then they can create multiple offspring before they die.

 

In short, the ability to procreate at a younger age was selected for because those that did had more offspring than those who waited longer to begin.

[ecoli]

The younger a life form is when it can begin reproducing, the more offspring it can have over it's lifetime. If boys and girls had to wait until they were 20 to start having children (during a time when average lifespan was 30), then they'd have very few offspring. However, if they can start reproducing at 11 or 12, then they can create multiple offspring before they die.

 

In short, the ability to procreate at a younger age was selected for because those that did had more offspring than those who waited longer to begin.

 

Sure... but it wouldn't help if your children keep dying because a 12 year old isn't fit to raise a baby.

[iNow]

Sure... but it wouldn't help if your children keep dying because a 12 year old isn't fit to raise a baby.

 

That would itself be selected against as well.

[ecoli]

Evolution only acts in response to how many children you have. What you do before that cannot malke any difference.

Incidentally masturbation is pretty common amongst animals so it's a safe bet we were doing it before we were human.

 

Evolution acts on the fitness of individual, which is, in part, a measure of your offspring. What you do before you have children most certainly affects your fitness. For example, if you cut off your genitals before you have children, this will most certainly affect your Darwinian fitness!!

 

Yes, other animals masturbate too, perhaps because young adults are less adept at rearing children in many types of animals, then older adults.

 

This makes sense, especially if you consider the reproductive strategy (k selected) of humans and other mammals. Human babies are fewer in number but we take the time and energy to raise our babies so they survive for relatively long periods of time. Why risk having offspring too young have simply have them die? It doesn't make sense.

 

That would itself be selected against as well.

 

what I'm proposing, is that masturbation is getting selected for because it delays the onset of reproductivity to a better, healthier age. That will increase the darwinian fitness of both the parent and the offspring. the offsrping is less likely to die, and the parent is less likely to loose a child, which, even in other primates, has shown to cause depression, etc (which would decrease fitness).

[iNow]

This isn't so much in response to anyone, just a general comment. The higher the sex drive of an organism, the more likely it will be to reproduce successfully. Masturbation is generally an expression of that sex drive, not incredibly useful in itself, more like an emergent phenomenon of an evolved trait.

[ecoli]

This isn't so much in response to anyone, just a general comment. The higher the sex drive of an organism, the more likely it will be to reproduce successfully. Masturbation is generally an expression of that sex drive, not incredibly useful in itself, more like an emergent phenomenon of an evolved trait.

hmm... it would be interesting to have a statistical representation of that in human populations. ie - correlation between masturbation frequency and perceived social status/ number of children/ number of lovers/ etc.

In my mind, the stereotype is that the nerd who can't get the girl spends all the time masturbating, while the jock gets laid (doesn't need to masturbate). This stereotype (and I'm sure it's only that) tends to the opposite of what your saying. I wonder what the statistics would show.

[CDarwin]

Yes, other animals masturbate too, perhaps because young adults are less adept at rearing children in many types of animals, then older adults. [/Quote]

 

Primates at least tend to masturbate at all ages, especially as a means to reduce stress and boredom. It's particularly common in captivity. That seems to be the activity's function, especially as it doesn't really suppress sexual arousal in males or receptibility in females in any sort of long term.

 

This makes sense, especially if you consider the reproductive strategy (k selected) of humans and other mammals. Human babies are fewer in number but we take the time and energy to raise our babies so they survive for relatively long periods of time. Why risk having offspring too young have simply have them die? It doesn't make sense.

 

Have you ever heard Margaret Mead's saying, "It takes a village to raise a boy"? Well, that's a approach most cultures take to child rearing, which mitigates the immaturity of the mother or father. Also, in most cultures an adolescent's first lover isn't another adolescent but someone much older and experienced who could be expected to help in raising a child.

 

Your hypothesis also doesn't sync up with the ages at which males and females of most primates reach maturity. Males, who bear the least health risk from a pregnancy (logically) become sexually mature later than the females who bear the lion's share of the risk. Most cultures reinforce this by expecting females to begin reproducing at an earlier age than males.

 

This isn't so much in response to anyone, just a general comment. The higher the sex drive of an organism, the more likely it will be to reproduce successfully. Masturbation is generally an expression of that sex drive, not incredibly useful in itself, more like an emergent phenomenon of an evolved trait.

 

It is useful, as a stress-relieving device.

[SkepticLance]

Why should masturbation be selected for at all?

 

In my view, what evolution selected for was a powerful sex drive. The human male has a portion of his brain dedicated to sex drive, and that portion is four times as big as the equivalent in the human female. Evolution selected the randy male. Because the level of randiness was too high to permit satisfaction with male/female sex every time the guy got the hots, those randy and frustrated people did the only thing that was left to them. There is no reason why the masturbation behaviour should have bee a result of evolution. It was just a side effect of evolution for strong sex drive.

 

While females are also known to masturbate, they do it less frequently than males, and only 50% of sexually inexperienced females do it at all. However, the reason why they do it is likely to be similar to males - gaining one kind of satisfaction when the other is not available. It does not have to be the direct result of evolution - just a side effect.

 

A comment on life span. This is totally unaffected by masturbation. Humans live a long time because of the grandparent effect. Evolution selected genes for long life span, because having grandparents assisted in the survival of the grandchildren. Thus long life span was an evolutionary advantage.

 

Clearly, how much a young person masturbates does not affect the grandparent effect, and cannot alter evolution for life span.

[CDarwin]

Why should masturbation be selected for at all?[/Quote]

 

Again, stress-relief. Here's another idea: http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=FPR2004075002114

 

In my view, what evolution selected for was a powerful sex drive. The human male has a portion of his brain dedicated to sex drive, and that portion is four times as big as the equivalent in the human female. Evolution selected the randy male. Because the level of randiness was too high to permit satisfaction with male/female sex every time the guy got the hots, those randy and frustrated people did the only thing that was left to them. There is no reason why the masturbation behaviour should have bee a result of evolution. It was just a side effect of evolution for strong sex drive.

 

While females are also known to masturbate, they do it less frequently than males, and only 50% of sexually inexperienced females do it at all. However, the reason why they do it is likely to be similar to males - gaining one kind of satisfaction when the other is not available. It does not have to be the direct result of evolution - just a side effect.

 

That would be an interesting idea to test. I'll get the grant application started.

 

My gut says no. As I've said before, masturbation and sex are different animals. Masturbation occurs in the absence of the sexual signals that arouse an animal to reproduction and probably doesn't satisfy the basic reproductive urge. Animals who are perfectly sexually active masturbate; you'd have to explain that away.

 

A male who's aroused whenever he sees a female might not necessarily be the most reproductively successful, either. In many mammalian, and especially primate, and especially especially human, societies females are selective. This means really wanting it might not necessarily result in getting it.

 

This might be salient:

http://www.springerlink.com/content/k7508l6033g17187/

[Dom203]

wow - lots of responses!

I suppose I'm wrong and you're right!

 

However...

In answer to "wouldn't the same happen to women who masturbate?" - Women KNOW if they've reproduced properly because they'll get pregnant, however men don't notice any bodily changes after they masturbate OR reproduce, so they don't KNOW if they've reproduced or not (I don't mean in their CONSCIOUS mind).

 

Also, in answer to "animals do it too and they don't live any shorter now." - how do we know that animals didn't have longer lifespans years and years ago?

 

 

Thanks

[insane_alien]

Also, in answer to "animals do it too and they don't live any shorter now." - how do we know that animals didn't have longer lifespans years and years ago?

 

fossilized bones. you can get a pretty good estimate of somethings age bylooking at how developed the bones are. it seems to have remained pretty constant throughout history for most species except humans. we developed medicines and better living conditions for ourselves so have increased out life expectancy considerably(more than doubled)

[Paralith]

wow - lots of responses!

I suppose I'm wrong and you're right!

 

However...

In answer to "wouldn't the same happen to women who masturbate?" - Women KNOW if they've reproduced properly because they'll get pregnant, however men don't notice any bodily changes after they masturbate OR reproduce, so they don't KNOW if they've reproduced or not (I don't mean in their CONSCIOUS mind).

 

It doesn't matter if you KNOW, consciously or unconsciously, that you've reproduced. What matters is if the genes that led to certain behaviors resulted in more children being born with those genes, then those genes will increase in frequency in the population as generations pass. So, if a male had genes that "told" him to die after a certain number of ejaculations, and if he also had genes that "told" him to masturbate a lot, then he would waste all his ejaculations on masturbation and he would leave no children, and his genes would cease to exist in the population. It simply wouldn't work, my friend.

[DrDNA]

It doesn't matter if you KNOW, consciously or unconsciously, that you've reproduced. What matters is if the genes that led to certain behaviors resulted in more children being born with those genes, then those genes will increase in frequency in the population as generations pass. So, if a male had genes that "told" him to die after a certain number of ejaculations, and if he also had genes that "told" him to masturbate a lot, then he would waste all his ejaculations on masturbation and he would leave no children, and his genes would cease to exist in the population. It simply wouldn't work, my friend.

 

 

Para is 100% correct. They only way that this could possibly effect the gene pool is if there were a selective advantage or disadvantage to the act. It MUST lead to more or fewer offspring for some chnge in the gene pool to occur.

 

For example, if women knew of this behaviour and it exicted them so these guys, therefore, had more successful mating interactions and had more offspring. Or if playing with oneself strenghthens sperm or something in the sperm to make it more potent, therfore, these guys make more women pregnant and have more offspring than their buddies who do not participate in the behaviour.

 

Conversely, if the behaviour repulses potential mates so they would not mate with this kind of person or if they avoid interactions with women because they are stuck in their bathrooms all day. Or for example, if a male had just a limited number of ejacs in him and those males used them all up, they wasted the good seed fooling around with themselves.... Then, they could have a selective disadvantage (IF the physiology was correct...which it is not).

 

Of course the above hypothetical scenarios are completely deemphasized by the use of modern birth control technologies, abortion, one man one wife, societal or religous practices which frown on non-marital sex, etc.....

[John Cuthber]

"Originally Posted by John Cuthber

Evolution only acts in response to how many children you have. What you do before that cannot malke any difference.

Incidentally masturbation is pretty common amongst animals so it's a safe bet we were doing it before we were human.

Evolution acts on the fitness of individual, which is, in part, a measure of your offspring. What you do before you have children most certainly affects your fitness. For example, if you cut off your genitals before you have children, this will most certainly affect your Darwinian fitness!!"

 

Unless (as a hypothetical example) you cut them off because it would let you use them in some strange cloning experiment which would alow you to produce hundreds of children. Then you would be an evolutionay winner because you had lots of kids.

Evolution measures success by how many copies of yourself you leave behind; it doesn't know or care what else you do.

Evolution has a strong reason to produce creatures that want lots of sex- that's the obvious way of getting lots of offspring.

A lot of animals (including humans) find themselves short of an oportunity to express that urge; no prizes for guessing what they do about it.

[PhDP]

I read few evidences here that masturbation was adaptive; it might very well be a by-product.

 

It MUST lead to more or fewer offspring for some chnge in the gene pool to occur

 

Evolution measures success by how many copies of yourself you leave behind

 

Not necessarily. Fitness is the contribution made to future generations; it's possible to have a higher fitness with fewer offspring and lower survival rates.

[lucaspa]

Well if this is so, then if you masturbate from a young age, your body would assume you were having sex, and therefore having kids very early on, meaning you're not needed much after that - you've reproduced!]

 

This doesn't work. After all, a trait gets passed down only if you reproduce. So males that masturbate but don't reproduce later won't have kids. And therefore you lose the males that masturbate from a young age but dont have sex.

 

Natural selection is done with you after you have kids. Whatever happens to you after that is irrelevant to natural selection. Males tend to die earlier than females due to differences in the cardiovascular system: differences due to male sex hormones such as testosterone.

 

So, males are more likely to have heart attacks in their 40s and 50s than females. BUT, since they have already had kids, natural selection won't be able to eliminate this trait.

 

assumes they'll reproduce from a young age!

 

Natural selection only works when you DO reproduce, not "assume". If the assumption isn't carried thru, then ...

 

Evolution measures success by how many copies of yourself you leave behind; it doesn't know or care what else you do.

Evolution has a strong reason to produce creatures that want lots of sex- that's the obvious way of getting lots of offspring.

 

That's too simplistic. Remember, MOST mammalian (and other vertebrate) species have sex only when the female can get pregnant. Therefore, cats don't have or want "lots of sex" but sex very infrequently. In between, they don't want sex at all!

 

What matters is the number of surviving offspring compared to the other members of your species.

 

So, one strategy for a human male could be to get as many different women pregnant as possible but never stay around to rear the children. In our ancestors before technology, both pregnant females and nursing females and young children are vulnerable to lots of dangers: such as starvation and predators. Such a strategy may sire 100 children, but only 10 survive to adulthood.

 

Another male could use the monogomous strategy and stay with one female and take care of the kids. This male may only have 15 offspring BUT 12 of them survive to adulthood. In evolutionary terms, this strategy is more effective. If there is a genetic basis to this behavior, it will gain in frequency in the population.

 

After we have kids, natural selection is blind to what happens next. In effect, we are running on "momentum". The only hypothesis I have heard that provides an evolutionary explanation for longer human lifespans is the "grandmother" hypothesis. I'll have to see exactly where to find this but, in brief, it says that grandmothers (in primitive societies) help a lot in providing for their grandchildren: by gathering food, looking out for the kids, and being around to protect from predators. So ... women that lived longer and took care of their grandchildren would pass those longevity alleles to the population. Males simply got to go along for the ride because most of the genes were on the non-sex chromosomes.

[DrDNA]

Not necessarily. Fitness is the contribution made to future generations; it's possible to have a higher fitness with fewer offspring and lower survival rates.

 

Except of course, at an extreme end of the spectrum and your parents just so happen to be a horse and a donkey (and if fitness is defined as strength) = dead end......sorry couldn't help myself.....

 

The bottom line still directly relates to an increase in the numbers of viable individuals in future generations. Fitness is a difficult term to get your arms around comparatively speaking. What if a mutation allows successive gens to move into another niche?

[Mr Skeptic]

Natural selection is done with you after you have kids. Whatever happens to you after that is irrelevant to natural selection. Males tend to die earlier than females due to differences in the cardiovascular system: differences due to male sex hormones such as testosterone.

 

Natural selection may be done with you as an individual after you have kids, but it never was about you. So long as you have an effect on the propagation of your genes, you are still playing the natural selection game. As you mentioned later, taking care of your kids increases your fitness even if you have stopped having kids by then.

 

What matters is the number of surviving offspring compared to the other members of your species.

 

Why the comparison to the rest of your species? So long as, on average, more than one copy of your genes are passed on, your genes will get passed on and increase in number. Tautologies can make things simple, hmm?

 

Just because you are less fit than the rest of your species doesn't mean your genes go the way of the dinos.

 

So, one strategy for a human male could be to get as many different women pregnant as possible but never stay around to rear the children. In our ancestors before technology, both pregnant females and nursing females and young children are vulnerable to lots of dangers: such as starvation and predators. Such a strategy may sire 100 children, but only 10 survive to adulthood.

 

Another male could use the monogomous strategy and stay with one female and take care of the kids. This male may only have 15 offspring BUT 12 of them survive to adulthood. In evolutionary terms, this strategy is more effective. If there is a genetic basis to this behavior, it will gain in frequency in the population.

 

After we have kids, natural selection is blind to what happens next. In effect, we are running on "momentum". The only hypothesis I have heard that provides an evolutionary explanation for longer human lifespans is the "grandmother" hypothesis. I'll have to see exactly where to find this but, in brief, it says that grandmothers (in primitive societies) help a lot in providing for their grandchildren: by gathering food, looking out for the kids, and being around to protect from predators. So ... women that lived longer and took care of their grandchildren would pass those longevity alleles to the population. Males simply got to go along for the ride because most of the genes were on the non-sex chromosomes.

 

In summary, what you do after you are done having kids can still be part of natural selection. The better care you take of your offspring, the longer-lived your species should grow.