PMS Evolved to End Bad Relationships, Says Scientist

[Baresark]

While all of that is true, if you read the rest of my previous statement, anthropological studies point towards the "nuclear family" unit in primitive societies.

The question is, how many of those contemporary primitive societies can be considered representative of humans as a whole, at least in case of this topic and associated choices. It could be my false impression, but isn't a significant percentage of currently existing ones bound to a specific climate and conditions? Not sure if there's a decent number of societies in more harsh areas (like eg. far-north?) that are also comparable in terms of development with their eg. "deep jungle counterparts". That does not mean I consider extreme an average environment for our ancestors, but it could mean we are missing a huge part of the picture. Note that I am not claiming anything at this point, more like being curious and doubtful at the same time.

We can sit here and talk about what we think all day long, the only issue is there hasn't been any findings of larger family units in primitive remains, so far as I have read about.

Again - not claiming anything, but it's difficult to categorize findings if we have only limited clues about the society itself - if there was any model that could fit a geographically and climatically (if there's such a word ) diversified and ridiculously long phase of development.

You are also suggesting that the world was a death ridden place, but any society works towards the relative safety of it's people. That means education about the world around them such as avoiding larger animals that can kill them, avoiding poisonous or dangerous food, and primitive morning and burial rituals worked against disease development.

True, but the efficiency of those methods hasn't been overly impressive in the past. Obviously, tens of thousands of years can easily mean that it simply resulted in the extinction of those groups that failed *too much* while the system worked at some level. But...

But to assume that the only possible way is the "shotgun approach" isn't realistic.

I prefer to assume "shotgun approach" as the only *effective* way that could realistically work over time. What else was there - proto-contraception? Not really encouraging if preventing pregnancy is the main goal. Abstinence? We still have to figure out that one Lucky guesses about future mortality rate and failure of unlucky groups? Selective breeding? Hm, this one could have some merit, but... quite a lot of talking necessary (and a knowledge I don't have). This is my main issue - reducing number of pregnancies would require a certain amount of know-how and resources and/or quite a bit of social development. Reducing number of children was less complex as it could happen either by simple action, inaction or regardless of any - and we can observe certain aspects that seem already pretty well developed in ancient societies, along with myths and rituals.

As for findings itself - I honestly don't know how they are interpreted in the first place. The amount of certain skeletons among random groups? Burial sites, with the assumption that eg. discarded children even got there? Not to mention a nomadic lifestyle that could also exclude probability of reconstructing a picture to a significant extent.

Still, that's all I can do at this point - accept your answers about the data, express doubt about their interpretation.

I agree completely about a few of your points. An accurate picture of the past is not possible. But we trust anthropologists (at least some of them) to put to together as accurate of a picture of past societies as they can based on their body of work. It's extremely tricky to get an accurate picture of the past in recorded history (ie. Historians fight constantly about how lots of events took place), but it's even more difficult when you look at pre-recorded history. It's like putting together Dinosaur fossils. We think we got it, but we could be completely wrong about the dinosaurs, and we have no way of knowing. We just trust that enough of them have tried and came to the same conclusion that it's in the ballpart of being right.

Contemporary primitive societies can only be taken at face value. We know what they are like now. We know why they do things now. Over the last 180,000 years, many things could have changed that would make them live differently now than then. I think a major part of why it is considered at least a somewhat accurate account is because all primitive societies that are around today tend to, as a whole, favor the small family unit. Like I said, every society has some people who want more (ie. more kids, more land, more food), but the societies as a whole place their values differently. Also, I feel it's important to point out that the whole "nuclear family" unit is an approximation. The birthrate in the US, for example is 2.1, not 2. It's because of where the bell curve peaks that it's slightly higher than 2. I imagine that primitive societies had this same kind of thing. On average it was 2 kids, but some had more and some had less or none.

I agree with your conclusion though: Take the proof as proof, but always remain skeptical.

 

[Baresark]

Seems more likely that the far more complicated nature of female biology and hormone interaction can have unusual effects on brain chemistry. This evolutionary trait idea assumes

1. That early and pre-humans were monogamous.
2. That a female, after driving one male away, would then still be desirable to other men.
3. A female exhibiting regular PMS would be allowed to stay in the society.
4. That it was more common for the male to be infernal than the female.
5. The lack of offspring wasn't enough to clue the male and female in to the fact that the breeding wasn't working.

All of those assumptions seem questionable at best. Behavior like that seems more likely to be a negative survival trait in a primitive social community.

The only thing I can say in disagreement to your statement is that there is a large and mounting body of evidence that suggests that primitive humans were monogamous. Many people look at the powerful in recorded history, see that many societies had people with lots of kids and many wives, and assume that to be the norm. That would not be the norm in any society, especially in primitive societies.

But many of your points seem spot on. For instance, to me it seems like this theory relies on someone being constantly producing offspring. Otherwise, between births they would have a menstrual cycle that would produce PMS symptoms again and the only thing to do to stop them is to impregnate your mate again. In other posts I have pointed out that sex is not only for reproduction in humans and some other higher species of primate and sea mammals. Since sex plays an important role outside of reproduction (ie. keeping the bond between a mother and father strong so both stay present to increase the likelihood of the offspring surviving to adulthood), then PMS would be a force that drove a partner away after successfully producing offspring, decreasing the chance of survival of the offspring.

 

[Harpalyce]

LARGE, LOUD SIGHING

Oh boy, articles like this are my favourite. FAAAAVOURITE.

Behold, ladies and gentlemen, a classic example of somebody trying to talk what they don't know about, and a dude trying to make the data fit a situation because they want it to support their presupposition.

PMS is about as much of an evolutionary adaptation as PCOS is, or depression is, or maybe lung cancer. Because as we all know these diseases give you super special powers, right? Never mind that it's an actual disease and syndrome that people suffer through, we gotta turn it into some X-Men level shit ASAP. And there go my eyes, rolling straight out of my head across the ocean to Australia to be eaten by a cane toad.

It's not an adaptation. It's the exact opposite. Perma-pregnancy isn't the answer to that problem because very rarely was that expected to happen - you can even look to human biology for this. Quite frankly, humans are really terrible at knocking each other up. Just go look up some statistics - it's one of the reasons why trying to figure out the mechanics of some of these methods of birth control, like copper IUDs, because it's just difficult to figure out why the body does what it does.

More to the point, PMS IS A DISORDER. It is NOT a natural side-effect of any given vagina-owner's cycle. It is when those symptoms become debilitating and extreme. Brushing off what the hormones just do is extremely naiive and straight-up false. And if anyone is going to argue with me on this, please, by all means, tell me how I'm just overreacting when I don't like to bleed for three weeks at a time with chunks of my uterus - yes, bloody chunks of my own flesh, dropping into the toilet bowl like tiny jellyfish, or maybe not so tiny given that they range from dime size at smallest on up to quarter-dollar, coupled with constant bleeding that means I soak through what most consider to be an adequate allowance for an entire night - and how it's just silly women's problems to think of this, a condition that would be as 'evolutionary advantageous' as this person is saying since it is 'cured' with pregnancy, as an incredibly unacceptable situation. Then if you continue to argue that these are just silly women's problems and no biggie, I will track you down, find your house, and smear chunks of my uterus all over your car before finding where you sleep and dripping onto your sleeping face.

And if you need more reason why this doctor's theory is utter hogwash, PMS is well known to be comorbid with disorders that CLEARLY don't have a damn advantage to them such as depression, anxiety disorders, and postpartum depression. It's estimated that 50-70% of people with PMS will have one or more of these disorders in their lifetime. That is certainly a rate that completely eliminates the supposed advantage that PMS gives according to this person - consider, for example, that postpartum depression is the exact opposite of what you want from an evolutionary point of view, because it causes the mother to neglect or perhaps even hate her offspring. And offspring is what it's all about in evolution, because they carry your genes.

Here's a lovely bit talking about PMS's comorbidity with other disorders, by the way - http://www.medscape.com/viewarticle/705605_4

 

[Jonathan Funcke]

Nothing like gender politics to make people want to completely disregard something without putting any thought into it.
Yay for the L.C.D of humanity.

How about we take this in steps:
1) Evolution implies that our bodies exist in this state to fulfill a purpose suited to the environment. (with the exception of evolutionary leftovers that slowly remove themselves over time, I'm looking you Mr.Appendix).
2) PMS exists.
3) Thus there should be a reason for it to exist, otherwise the body would develop mechanisms to reduce the pain such as increased dopamine levels to counter it(pain = distraction = more likely to become prey).
4) This theory gives reason for the pain to exists, a warning that a cycle has ended in failure (not pregnant = failure from the body's perspective).
5) This also gives reason to why some women experience increased arousal during their menstrual cycle (a time where sex should be useless), as it increases desire (and hopefully find a fertile mate).

This theory makes sense, but requires a case study to give it more validity. If other animals also experience p.m.s then that would bolster this theory further.

In conclusion: there is still more work to do be done, but good job science!

 

[lacktheknack]

Note, most women do not experience PMS, and its actually contested if it even exists in the first place. This theory is illogical.

*citation needed*

Clearly, you've never lived for ten years with a sister in a state of permanent menstruation.

Ok firstly, thats just a bitchy woman.

Secondly, there is side effects from Periods, likes cramps, which can piss a women off, but its the same way if I punch you in the face and give you a black eye, you haven't got Post Swelling Syndrome, your just pissed off cause it hurts. There is no such thing as PMS from a hormonal reason, just a "My period is annoying" reason. A woman whos a ***** will ***** more if shes cramping, whether its from running after food or a period.

You know, you're really doing yourself no favors when you call my sister, the sweetest girl in the world, "just a bitchy woman". The non-stop PMS that she lived with for ten years (TEN YEARS) didn't make her angrier, it caused her to have manic mood swings in both directions, along with a host of other emotional instabilities despite the fact that her period was not painful.

You're doing the opposite of convincing me that PMS doesn't exist when you make wild and wrong assumptions, say stuff I KNOW to be BS, and still don't cite your statements.

But please, tell me more about how non-existent cramps naturally cause both anger AND manic happiness, how my sister was totally just mentally ill for ten years before her hysterectomy, and how you know soooo much more about PMS then a guy who's lived through ten straight years with someone who has it non-stop.

 

[PhiMed]

snip

I would love to respond to what you said, but I don't play the break down and approach idea by idea game.

So, you dislike how I structured my post, so you can't be bothered with responding, other than to say you object to the way in which I wrote it? That's a bit petty, isn't it? If you don't want to respond, then don't. Don't just criticize how I arranged the text, then take your ball and go home. It's a good thing they're no longer disciplining low-content posts here, because this would pretty much be the definition of one.

I only chose to present it that way because quoting your post in its entirety in one block, then referring to your individual points before I explained why I took issue with them would be too cumbersome. I don't feel like I was disrespectful or insulting in my post, but I feel like your post was supposed to make me feel bad about... something. I don't really understand why you're taking offense to compositional structure, rather than content.

I wasn't insulted, but the constant breaking down of posts has, in my experience, always lead to the central idea of a post being left behind. You end up responding to little things here and there and then the whole reason for the post is lost.

But I will, in the interest of debate, respond to your post... though I'm not going to break it down as you did.

Only, it's been shown that sex is not solely for reproduction in humans. Unless you're implying that this will result in a higher likelihood that their offspring will survive to reproduce, this is also irrelevant. Evolutionary stress does not care about an individual organism's emotional well-being.

You improperly broke up these ideas, one of the reasons I dislike breaking down whole statements into individual ideas. Both parents present greatly increases the likelihood that offspring will survive. It's the presence of both parents that increase the likelihood of survival. Sex is also a way of keeping the man and woman interested in each other because humans have a long period of time before one of our offspring is capable of caring for itself.

Quantifiably false. "Successful" from an evolutionary standpoint relies only on the number of progeny that reproduce. If a pair only replace themselves, then their genes will not propagate. Simple as that. 50% of the population has the genes of Genghis Khan as part of their genetic makeup. I'd say that, from an evolutionary perspective, that is one successful organism. Do you think he did that by just having one son and one daughter with one woman?

Number of progeny is completely irrelevant if you cannot ensure their survival to adulthood. More mouths to feed and more attention divided between a large number of offspring does not ensure survival of the young. In nomadic societies food is not ensured (as it was not for the first several thousand years of civilization). It's easy to point out to a single incredible instance of genetic propagation and call it the most successful. I also pointed out in my previous posts that most people were not rich or powerful enough to see so many young survive. Forget the fact that my references were EXCLUSIVELY aimed at pre-civilized life and not anything that happened after 8,000 BCE. We know that in the civilized world (ie. time when humanity settled down into non-nomadic societies and city states), it was common place for the "shotgun approach" to be used. Food was a lot more scarce and hard to come by for large and growing civilizations than it was for primitive hunter-gather societies who's size was limited by the amount of food that could be found or hunted.

Nope. Genes that persist in large numbers do so for a reason. If you are referring to traits which have an incredibly low frequency, then perhaps this point could be defensible, but for a trait to be this pervasive, there must have been an evolutionary advantage to it at some point. Otherwise, it would not have become so ubiquitous.[/qhote]

You are incorrect. A trait with no downside will persist, even if it does not provide any kind of advantage. It simply has to be a common trait in the population and not be selected out (ie. offer a disadvantage).

Hmmm... I've heard arguments like this before.

How old do you think the world is, in years?

 

[Lightknight]

More to the point, PMS IS A DISORDER. It is NOT a natural side-effect of any given vagina-owner's cycle. It is when those symptoms become debilitating and extreme. Brushing off what the hormones just do is extremely naiive and straight-up false.

Actually, if you flushed progesterone and estrogen in a male's system you would also see PMS symptoms. It is a natural side effect. It's just that it's worse for some people than it is for others but it's still there for most people. It's just that hormones are a hell of a thing.

And if anyone is going to argue with me on this, please, by all means, tell me how I'm just overreacting when I don't like to bleed for three weeks at a time{/quote] Three weeks? There is something specifically wrong with it lasting that long. That's atypical. If it's really lasting you three weeks then you should absolutely speak with your physician. Holy crap and congratulations on making me horrified about your situation when I was largely desensitized to this stuff before my first semester of pre-med was through. You tell your physician to give you a lollipop after your visit too. None of that sugar-free bullshit either. Legit cream-based goodness on a stick or nothing. And a sticker. Sure you're probably an adult but who doesn't like a sticker?

And if you need more reason why this doctor's theory is utter hogwash, PMS is well known to be comorbid with disorders that CLEARLY don't have a damn advantage to them such as depression, anxiety disorders, and postpartum depression. It's estimated that 50-70% of people with PMS will have one or more of these disorders in their lifetime. That is certainly a rate that completely eliminates the supposed advantage that PMS gives according to this person - consider, for example, that postpartum depression is the exact opposite of what you want from an evolutionary point of view, because it causes the mother to neglect or perhaps even hate her offspring. And offspring is what it's all about in evolution, because they carry your genes.

Here's a lovely bit talking about PMS's comorbidity with other disorders, by the way - http://www.medscape.com/viewarticle/705605_4

Exactly. PMS is the side effect of a process that is necessary for life. It's the same as the disadvantage women have with a wider pubic angle of the pelvis. It is wide enough to make weight distribution and movement more difficult but the reason it's there is to allow a human life to pass through without harming the mother or child.

People need to understand that side effects of necessary evolutionary traits are sometimes just shitty.

Also, I've mentioned this a few times without response but women who are pregnant are prone to even more mood swings than women on PMS. So these doctors are full of shit.

 

[Lightknight]

You are incorrect. A trait with no downside will persist, even if it does not provide any kind of advantage. It simply has to be a common trait in the population and not be selected out (ie. offer a disadvantage).

The trait will persist if it coincides with a trait that is beneficial. In this case, the cycling of progesterone and estrogen "refreshes" the uterine environment with a new uterine wall for egg implantation along with a new egg. Without this cycle, mammalian reproduction would be impossible. I'd say the ability to meter out a limited supply of eggs over one's life time while preventing fertilization of 8 or more eggs at once is a pretty damn useful trait. That it screws with women's emotions for five or so days isn't even an ant bite compared to the benefit it provides to reproduction. Almost any trait that benefits reproduction will continue regardless of the side effect.

Hmmm... I've heard arguments like this before.

How old do you think the world is, in years?

I know you were asking this to someone else but just the nature of your question caused a bit of a spark of thought for me. How long in human history have women really had the option to leave a male? The entire argument of this article presupposes that women were in control of relationships and were able to easily end the relationship but this still isn't the case in several societies today and certainly wasn't hundreds of years ago in the vast majority of the world. Let alone thousands of years ago when getting raped and pillaged was just Tuesday. There's even the question of how long we've been social in any meaningful way where PMS would have mattered anymore than it does in animals.

 

[Baresark]

snip

Hmmm... I've heard arguments like this before.

How old do you think the world is, in years?

Ummm, that is a rather strange question. It's 4.3 Billion years old, at least last time I checked. Human remains have been found that place people at least as old as 180,000 years old, in our present incarnation (ie. fully erect when we stand with all of our bits where they presently are). Science has traces about 160 genetic traits that have only occurred in the last 20,000 years or so (estimated of course). Though, secretly everyone loves to think evolution requires millions of years, when thousands do for small things like Lactase production in human adults.

It's clear what you were thinking, and you do little for this educational back and forth by thinking things that were not explicitly said. What part of what I said lead you to that conclusion?

 

[Baresark]

You are incorrect. A trait with no downside will persist, even if it does not provide any kind of advantage. It simply has to be a common trait in the population and not be selected out (ie. offer a disadvantage).

The trait will persist if it coincides with a trait that is beneficial. In this case, the cycling of progesterone and estrogen "refreshes" the uterine environment with a new uterine wall for egg implantation along with a new egg. Without this cycle, mammalian reproduction would be impossible. I'd say the ability to meter out a limited supply of eggs over one's life time while preventing fertilization of 8 or more eggs at once is a pretty damn useful trait. That it screws with women's emotions for five or so days isn't even an ant bite compared to the benefit it provides to reproduction. Almost any trait that benefits reproduction will continue regardless of the side effect.

That is a fanciful thing you say. Traits through natural selection are random. A great many people like to imagine that only the good survives the process, but many traits are just traits that persist because there is no reason for them to be selected out. Of course, many traits co-exist with other traits (ie. Sickle Cell Anemia is a product of an evolutionary adaption to Malaria. But that is literally the mutation of that same gene. You could not get rid of one without getting rid of the other).

In the thought present behind this theory, a woman would have to be perpetually pregnant to avoid getting PMS. A baby only stops PMS while the woman is pregnant. As soon as she went back to her normal cycle, she would experience the same symptoms again, month after month, until she was pregnant again. If you read my previous posts, I have pointed out that a large body of evidence suggests that larger family units were not the norm until well after civilization came about. Though an adaptation could have come about only in the last 10,000 years that has made the symptoms of PMS appear.

I see what you and others are doing, you are looking at it solely from the biological perspective, but that is one dimensional. You need to look at evolution from other perspectives as well, such as evolutionary psychology. You cannot look at biology and explain the actions of people.

 

[VladG]

Interesting, the presumption that evolution directs itself towards purposes. Any actual benefit from evolution not related to natural selection is serendipitous at best, my friend. PMS does not exist for this purpose. It does not exist for any purpose. It simply exists.

Uhm.. how exactly is the ability to find viable mates NOT a part of natural selection?

This sounds plausible, but who knows... a flat earth sounded pretty damn plausible for a lot of people at one point (and sadly, still does).

 

[VondeVon]

I wonder if other mammals have PMS.

An interesting theory but I can't imagine any but the rare exception's PMS would be worse than the mood swings and needs of a pregnant woman. I theorise that sterile males were happier with their partners than others.

 

[Harpalyce]

More to the point, PMS IS A DISORDER. It is NOT a natural side-effect of any given vagina-owner's cycle. It is when those symptoms become debilitating and extreme. Brushing off what the hormones just do is extremely naiive and straight-up false.

Actually, if you flushed progesterone and estrogen in a male's system you would also see PMS symptoms. It is a natural side effect. It's just that it's worse for some people than it is for others but it's still there for most people. It's just that hormones are a hell of a thing.

Dude, the fact that you're arguing "PMS is a natural side effect and not a real syndrome"" while mentioning your medical training is really really not cool. Yes, hormones are some heavy-hitters; yes, they've got full-body huge effects, since that's what they do.

But PMS is specifically when those symptoms become crippling. Like many other disorders, there's a point at which it takes over your life. A natural process pushed to an extreme is when it becomes a syndrome. For example, there's increasing evidence and study about depression having an immunology component, e.g. it can be induced in mice by cytokines as a function of sickness behavior*. Of course sickness behavior and cytokines are natural processes. Of course if you inject somebody with all those cytokines, you'll see sickness behavior. But that doesn't mean depression is bunk. Depression is what happens when that sickness behavior gets stuck in a downward spiral that has huge and obvious effects on neurochemistry. Depression is what happens when it becomes crippling and makes a person unable to live a normal life.

PMS isn't just a natural side-effect and quite frankly the idea that it is (and therefore ladies should just suck it up and deal) is so ridiculous I can barely stop to articulate why. It is, as I mentioned, like saying the thing you say I should be given a lollipop for is natural. Yes, it's hormones having an affect on my body. If anything, it's the exact same set of hormones that control PMS. It's a real and crippling thing that really does disrupt people's lives. And therefore it's really hard to swallow that it is any sort of evolutionary advantage at all. Trust me, being greeted some mornings to what looks like a suicide bomber jar of marinara sauce decided to take out my underwear is no advantage at all.

PMS ain't just a natural thing, y'all. There's a reason it has SYNDROME in there.

*non-bio-major translation/explanation about the mice thing because I honestly find it extremely interesting and I was trained as a science writer so what the hell: So when you get sick, a lot of the whole feeling icky bullshit you go through is actually your immune system's doing. It's your immune system pretty much yelling "WOAH THERE SLOW THE FUCK DOWN" so it can do its work while you're flopped out asleep on your bed. Basically it wants that energy to fuel itself instead of fuelling you running around doing everything else, because you need to rest up and let it work. This is called sickness behavior. Now, your immune system is hella complex - you're probably vaguely familiar with terms like "white blood cell" and "antibody", but that's only one bit. (Literally it's so complex scientists are still figuring out just what does what and probably will be for awhile.) But one bit is cytokines. They act kinda like messengers, so imagine them as like obnoxious toddlers who run screaming through a crowd punching people's shins and getting everybody in a panic. So what some scientists have done is found a way to induce depression using these cytokines, and this goes like so: they inject a mouse with those cytokines, and they run around the mouse's immune system going "AAAA HOLY SHIT YOU GUYS WE'RE SICK AAAAA". That sets off the sickness behavior - lethargy, wanting to sleep all day, feeling 'down'. But then the sickness behavior gets stuck chasing its own tail. "We're lethargic, we must be sick because we're lethargic! Let's activate that sickness behavior to make us even more lethargic! Oh no we're lethargic, we must be sick..." so on and so on. And what happens is that actually ends up being a way to induce depression. That mouse's immune system gets so stuck in "we're feeling down, we must be sick, let's feel even more down" that it goes straight to being depressed. This thing that starts as an immune system response spirals down and down until finally it has major effects in the neurochemistry - in those head chemicals that made depression, well, depression. There are still a lot of people trying to tease out how exactly these things work, so you can find some nice piles of articles about it if you care to look on Google scholar.

 

[Lightknight]

Dude, the fact that you're arguing "PMS is a natural side effect and not a real syndrome"" while mentioning your medical training is really really not cool. Yes, hormones are some heavy-hitters; yes, they've got full-body huge effects, since that's what they do.

Of course it's a syndrome. That's what the S is for in the acronym, I didn't say it wasn't a syndrome but a syndrome isn't a disorder. Syndromes are literally defined as a consistently occurring set of side effect with no comment as to the severity of the side effects. If you'll reread your quote of me you'll see that my issue wasn't with it being a syndrome but with the comment that PMS isn't a typical side effect of the menstrual cycle that the vast majority of women experience. This, however, is clearly something you still disagree with me on so hopefully my next comment will alleviate the issue.

But PMS is specifically when those symptoms become crippling. Like many other disorders, there's a point at which it takes over your life. A natural process pushed to an extreme is when it becomes a syndrome.

Oh, here's the confusion. You are mixing PMS with PMDD. Premenstrual dysphoric disorder (PMDD) is the term for when the symptoms involved with PMS are so severe as to become a disorder.

Yes, PMDD is an actual disorder and can truly impact your life. But please don't confuse it with PMS. This is why I recommended you speak with your physician on the subject when you discussed the severity of your symptoms.

Here's a mayo clinic article I found on the topic if you're interested:

http://www.mayoclinic.org/diseases-conditions/premenstrual-syndrome/expert-answers/pmdd/faq-20058315

If you are suffering from PMDD then there are some treatments and lifestyle changes that can drop the symptoms down to tolerable levels for you. So please don't think that what you're experiencing is just normal nor that there's no hope in alleviating them for yourself. PMS is an almost universally experiences syndrome amongst women, PMDD is not. Just under 10% from what I remember. 8% if Wiki is to be believed, I had thought it was a little higher.

 

[Nieroshai]

Interesting, the presumption that evolution directs itself towards purposes. Any actual benefit from evolution not related to natural selection is serendipitous at best, my friend. PMS does not exist for this purpose. It does not exist for any purpose. It simply exists.

Uhm.. how exactly is the ability to find viable mates NOT a part of natural selection?

This sounds plausible, but who knows... a flat earth sounded pretty damn plausible for a lot of people at one point (and sadly, still does).

The point I'm trying to make, that every honest biology teacher tries to make, is that evolution has no direction. Natural selection weeds out fatal evolutionary traits, albeit inefficiently, but evolution is chaos. Evolution is unbound genetic variation. You don't evolve towards a purpose, you find a purpose for your evolution. Or else die.

 

[Lightknight]

That is a fanciful thing you say. Traits through natural selection are random.

Not really depending on exactly what you mean. New traits (mutations) can be random. But the survival of traits is usually ultimately defined by the beneficial or negative impact they have on reproduction. The reason natural selection is involved is because a beneficial trait will be passed on more frequently than a negative or competing but slightly less beneficial trait.

So, say creatures live in an environment where food is very high up and hard to reach. Over time, the members of the species who are more capable of reaching the hard to reach food are going to reproduce more than the members of the species who are less capable because well fed animals means less deaths by hunger, larger/stronger body, improved health in general, more energy to reproduce, more attractive to the other sex.

An easy example of this is in the bird study from the Galapagos islands called Darwin's Finches in which he observed specialized differences amongst a common type of bird according to region. On one island, a spoon shaped beak for scooping up insects is more beneficial due to the environment so the birds in that region were more likely to have that type of beak while one island over a narrow beak is more beneficial to get at insects found in that type of ecosystem.

So, that a gene mutated to produce a slightly wider or narrower beak was random, but that the gene survived and spread over the subsequent generations was not random but because it made the gene's owners more fit for survival and reproduction than those without it. It's really all probability. A 1% advantage means a 101 children where without it there would be 100 children. Over the generations the 1% advantage starts working with larger numbers and has an exponential increase towards population size.

Though, admittedly, a 1% advantage would be a tremendously advantageous trait.

A great many people like to imagine that only the good survives the process, but many traits are just traits that persist because there is no reason for them to be selected out. Of course, many traits co-exist with other traits (ie. Sickle Cell Anemia is a product of an evolutionary adaption to Malaria. But that is literally the mutation of that same gene. You could not get rid of one without getting rid of the other).

Sure, some things slide past the filter that is time. It is also erroneous to believe that we are the pinnacle of human evolution at this moment. Our physical bodies are rapidly becoming less necessary while intelligence is far more beneficial. That being said, it appears that our societies have largely turned natural selection on its head with the poor (presumably less skilled/educated) having more children and the more wealthy having fewer children. We may actually regress over time which would be weird.

In the thought present behind this theory, a woman would have to be perpetually pregnant to avoid getting PMS. A baby only stops PMS while the woman is pregnant. As soon as she went back to her normal cycle, she would experience the same symptoms again, month after month, until she was pregnant again. If you read my previous posts, I have pointed out that a large body of evidence suggests that larger family units were not the norm until well after civilization came about. Though an adaptation could have come about only in the last 10,000 years that has made the symptoms of PMS appear.

If you read my posts you'd see I've been advocating that this theory is bunk. From the fact that women were things and not able to enter and exit relationships easily to the idea that a pregnant woman often has more regular and even wilder moodswings when pregnant. If PMS scares men away, then pregnancy driven mood swings will f them up, yo!

I see what you and others are doing, you are looking at it solely from the biological perspective, but that is one dimensional. You need to look at evolution from other perspectives as well, such as evolutionary psychology. You cannot look at biology and explain the actions of people.

Eh, no. Sorry. You've earmarked me for the wrong side. I just took a general issue with the way you said what you did. But you are technically correct. But overall the benefits of the menstruation cycle FAR outweigh the negatives of PMS.

 

[Baresark]

snipped for space consideration

I wrote this post and then accidentally closed the tab. So I'm going to try and hit the points I did before.

We are on agreement about most things. We both say this is bullshit. I think some of the points I mentioned may have come up as some kind of counterpoints to some of the things you were saying, but they were not.

We do disagree on the trait selection or lack thereof though. I am saying that traits can just exist without creating some sort of biological advantage, which is my reasoning behind this existing and not having a purpose. It is folly to think that nature is somehow attempting to build the perfect organism. It can't happen because our environmental stressors change all the time. But that does not make new trait not occur.

I am intimately familiar with Darwin's Finches and their beak differences. Darwin had insufficient time with the Finches. They required more study and more study was done way later. Further study has shown that the Finches have an average beak size that is not that different. The smaller beaks were for when seed shells were soft (ie, during seasons of adequate rainfall) and the larger for when they were harder shelled (ie. when there was not adequate rain that year). It shows that every island has an average beak size that the majority of the birds fit into. There were some with smaller than average beaks, and some with larger than average beaks, but most were in an average range. Darwin inferred from his studies that selection is acting on the birds beaks to make birds with either larger or smaller beaks. Only the average beak sized stayed the same from season to season, regardless of rainfall. There may have been an alternating (slightly) occurrence of prevalence of larger or smaller beaks, but the average beak size stayed the same. The environmental stress that caused differences in beak sized changed from year to year, but no one side was at a big enough disadvantage to be prevented from breeding. One year the smaller beaked birds were better off, the next it was the large beaked birds. The bird populations intermingled independent of the available food supply. The issue with Darwin's Finches is that with the short time he had to study them, it only let him take a very small sample of the population from the various islands, and the crew not being aware, only captured samples of birds that were different from average.

 

[KingsGambit_v1legacy]

PMS is something of a sensitive issue,

It is? Since when? Is that a new thing?

a woman in a "bad" relationship would experience PMS much more than other women.

LMAO. Come on, this is a joke, right?

"In the past, women had many fewer menstrual cycles than women in modern societies

OMG, seriously, come on now. Fewer menstrual cycles? Are you talking about Neanderthal women maybe? Or females of another species? 2 weeks, ovulate (and horniness), 2 weeks, menstruate (and PMS). It's pretty straightforward and happens regardless of how nice or big a jerk the boyfriend is.

 

[Lightknight]

We do disagree on the trait selection or lack thereof though. I am saying that traits can just exist without creating some sort of biological advantage, which is my reasoning behind this existing and not having a purpose. It is folly to think that nature is somehow attempting to build the perfect organism. It can't happen because our environmental stressors change all the time. But that does not make new trait not occur.

Yes, they can survive through the filter of time but if they are not somehow tied to a beneficial trait then they also need to not be in competition with a trait that is beneficial and therefore becoming a less fit trait themselves.

But generally speaking, traits will remain rare unless the groups expressing them also have other traits that coincide with it. So people who have two common mutations, one as a basic extra bone in the hand that doesn't help or harm anything and the second as a trait that makes them immune to a disease in the region. That extra bone would start to show up in larger numbers in future generations if that disease spreads only because it is assumed that the group with the extra bone survived to reproduce and expand while other groups contracted and intermarried with them.

But just one mutation with no commonly coinciding element? It should spread by itself in any significant numbers. Some things are random but the ravages of time tears things down to probability.

However, I digress. I think we both agree that neutral traits can persist. I just don't know if you agree with me or not that they would be rare unless tied to something beneficial even if totally unrelated.

I am intimately familiar with Darwin's Finches and their beak differences. Darwin had insufficient time with the Finches. They required more study and more study was done way later. Further study has shown that the Finches have an average beak size that is not that different. The smaller beaks were for when seed shells were soft (ie, during seasons of adequate rainfall) and the larger for when they were harder shelled (ie. when there was not adequate rain that year). It shows that every island has an average beak size that the majority of the birds fit into. There were some with smaller than average beaks, and some with larger than average beaks, but most were in an average range. Darwin inferred from his studies that selection is acting on the birds beaks to make birds with either larger or smaller beaks. Only the average beak sized stayed the same from season to season, regardless of rainfall. There may have been an alternating (slightly) occurrence of prevalence of larger or smaller beaks, but the average beak size stayed the same. The environmental stress that caused differences in beak sized changed from year to year, but no one side was at a big enough disadvantage to be prevented from breeding. One year the smaller beaked birds were better off, the next it was the large beaked birds. The bird populations intermingled independent of the available food supply. The issue with Darwin's Finches is that with the short time he had to study them, it only let him take a very small sample of the population from the various islands, and the crew not being aware, only captured samples of birds that were different from average.

Oh man... I've carried that misinformation for a long time. Middle school even so nearly two decades. The teacher even set up displays with multiple types of spoons that were better at getting the beans out of various containers... I glossed over the wiki section on the followup study. Should have read that.

How Darwin's finches never came up again in all my studies, including multiple courses on biology in university, I have no idea. Were they unaware of Darwin's mistake by the late 90's?

It is fortunate that the principle is still successful. If regions do vary enough then species of similar origin will evolve different sets of traits through natural selection (over significant time periods, of course).

 

[Lightknight]

PMS is something of a sensitive issue,

It is? Since when? Is that a new thing?

a woman in a "bad" relationship would experience PMS much more than other women.

LMAO. Come on, this is a joke, right?

"In the past, women had many fewer menstrual cycles than women in modern societies

OMG, seriously, come on now. Fewer menstrual cycles? Are you talking about Neanderthal women maybe? Or females of another species? 2 weeks, ovulate (and horniness), 2 weeks, menstruate (and PMS). It's pretty straightforward and happens regardless of how nice or big a jerk the boyfriend is.

I thought the same thing you did.

What he was saying, using pretty offensive terminology, is that PMS happens more frequently in an infertile relationship. He substituted the word "bad" for infertile. Something I took offense to. But if you're interested, he did respond to my complaint at the top of this page and was apologetic for the offense.

Additionally, he does define what he meant by "bad" in the article itself.