Older studies have shown opposite findings.
The study I have posted is the most recent one published in March 2008.
Bryan,
I have no idea about the stumptailed thing. I don’t really have a nicely-formed theory about MPB at all.
In general, I just get chafed by the mindset that evolution makes no mistakes and it’s all part of some glorious symphony of nature’s beauty. It’s not.
And of all animals, humans are certainly the LAST one to assume everything must have a good reason. Biomechanically and genetically speaking, humans a total mess. We’ve identified something like four thousand possible genetic defects that are possible in humans. Other species barely crack a few hundred.
Please address this issue which I’ve mentioned twice before:
“That doesn’t mean that it’s a DIRECT MECHANISM that the body uses to fight the disease, as in the moment the body detects prostate cancer, it sends the signal to the scalp to start balding!”
.
» Bryan,
»
» I have no idea about the stumptailed thing. I don’t really
» have a nicely-formed theory about MPB at all.
To me, it doesn’t really seem to be a big mystery. The example of the stumptailed macaques would appear to fit in nicely with the general theory that balding evolved as a mechanism to provide extra cooling to the brain. The prostate cancer theory does seem to be invalidated by the example of the monkeys, but not the brain-cooling theory.
.
Okay, now you’ve REALLY lost me.
Extra cooling for the brain?
Who has a “hot brain” problem in nature?
Surely not northern european-grown Caucasians, whom I think have a lot more MPB than those races that were rooted in hotter climates.
And why would someone’s brain be liable to get “hotter” as they got older?
And if there was anything backing this idea, then how does half the men out there not need the change WHATSOEVER and do just fine? No real-world cooling benefit in exchange for what is often a real sexual/societal handicap in appearance?
I think you guys are just reaching at thin air with that theory.
If our problem was “male pattern hirsutism” with older age, then couldn’t we just as easily and argue that the change was for “brain heating?” How bad can the “brain overheating” problem really be, when I could suggest the complete opposite idea and it sounds every bit as logical?
I still think a simple evolutionary foul-up makes as much sense as anything else I’ve ever heard for causing MPB. Or maybe a negative age-signalling trait.
We can’t find any demonstrable benefit for this change, it heavily affects half the men in the population and not the other half at all, and it’s a cosmetic handicap that can be quite severe.
» Okay, now you’ve REALLY lost me.
»
» Extra cooling for the brain?
» Who has a “hot brain” problem in nature?
Primates in general. In other words, animals who have more advanced brains that generate more heat with their greater inherent processing power.
Is this really the first time you’ve heard of the “brain-cooling” hypothesis for the development of MPB?? It’s been discussed a number of times on other hairloss sites.
» Surely not northern european-grown Caucasians, whom I think have
» a lot more MPB than those races that were rooted in hotter climates.
Sure, but that’s not really particularly relevant nowadays. MPB presumably started evolving in the human species LONG before they started migrating to colder climates (think: hot, sweltering Africa).
» And why would someone’s brain be liable to get “hotter” as they got older?
They don’t. What does THAT idea have to do with anything??
» And if there was anything backing this idea, then how does half
» the men out there not need the change WHATSOEVER and do just fine?
The evolution of balding is presumably a relatively recent event in evolutionary terms, so it hasn’t developed yet in everybody. I think it probably will gradually include ALL of humanity in the coming thousands of years, unless modern society has interfered with the process with technology (living in colder climates, air conditioning, etc.).
» No real-world cooling
» benefit in exchange for what is often a real sexual/societal
» handicap in appearance?
I think there IS a real-world cooling benefit, especially for people living in hot climates.
» I think you guys are just reaching at thin air with that theory.
The “brain-cooling” hypothesis makes as much sense as any other theory I’ve read about for the evolution of MPB. You can read more about it in the paper that Stephen Foote likes to cite so much: “Beards, Baldness, and Sweat Secretion”.
» If our problem was “male pattern hirsutism” with older age, then couldn’t
» we just as easily and argue that the change was for “brain heating?”
Sure. But you CAN’T argue for that, because that’s not our problem, is it? :no:
» How bad can the “brain overheating” problem really be,
» when I could suggest the complete opposite idea and it
» sounds every bit as logical?
I don’t understand the point you’re trying to make here. If our brains needed heating, why would we be LOSING our hair?? What’s logical about that?
» I still think a simple evolutionary foul-up makes as much sense as
» anything else I’ve ever heard for causing MPB. Or maybe a negative
» age-signalling trait.
That’s why I asked you about the stumptailed macaques. Do you think balding evolved in humans and macaques SEPARATELY, or do you think humans and macaques are descended from a common ancestor that first developed MPB?
» We can’t find any demonstrable benefit for this change, it heavily affects
» half the men in the population and not the other half at all, and it’s a
» cosmetic handicap that can be quite severe.
But it helps cool the brain, which was an even greater advantage thousands of years ago than it is today. Think about it: the idea is simple, and it makes a lot of sense.
.
As for the stumptailed macaque, I really don’t know. I’m not familiar enough with the prevalence of MPB in the various living primates to have a good idea about this issue one way or the other.
I guess brain-cooling COULD have theoretically been the source of it. I was partly reacting to the idea that it’s still a legit reason for the trait to be continuing now, which I don’t buy.
But MPB doesn’t seem to be the rule in many of the existing apes, right? So is it evolving separately? Why in the stumptailed macaques and the humans but not so much in the others? Would cranial size explain that?
Evolution is also eliminating more and more body hair in humans. Certainly back hair is no longer desired, for example. This is also androgen-controlled too.
But we don’t see all males being born with extremely hairy backs. We don’t see a quarter of all the males losing their back hairs slowly during their adult life to an internal immune-system attack. We don’t see the females of the species still generally preferring the fully-hairy males. (And this trait is supposed to be in the process of being selected away?) We don’t see aging males with shiny backs being the subject of ridicule in the pop-culture. We don’t see them resorting to spending thousands of dolars a year to wear giant shoulder-to-shoulder hairpieces out of sheer embarrassment & unhappiness with their condition . . .
I see MPB as probably just a foul-up now.
Maybe it had a legit brain cooling purpose when apes lived 5 million years ago on the African plains. But it doesn’t seem to be doing anyone a whole lot of good today.
This is an undesired triat that shows up on barely 15-20% of the males when you factor in the short cave-dwelling-era lifespans.
MPB is also MUCH, MUCH less present in females.
You could write that off as a product of the androgen-related cause, but I have another idea about that: Females get sexually selected for visual signs of health much more than males do, at least overall. So they are generally the first ones to have something sexually selected-away when it’s the slghtest bit unattractive. Body proportions & looks, skin wrinkles, hair grown overall (outside of MPB specifically), Acne issues (which is caused by more than just the androgen levels in the skin alone), etc. And let’s not forget that females are only sexually-selected & reproducing during their YOUTH, mostly in their teens and rarely ever past 40yo. And even when females DO get MPB, their frontal/hairline loss patterns make it way, way less visually obvious than with males for a long time.
What I’m saying about females is this: The certain portion & age of humans that have been by far the most sexually-selected for good looks over the thousands of years . . . also shows a rate of visible MPB that is virtually nil.
As far as I can see, this trait definitely does NOT seem to be encouraged by the natural selection process. Not these days.
» Please address this issue which I’ve mentioned twice before:
»
» “That doesn’t mean that it’s a DIRECT MECHANISM that the body uses to
» fight the disease, as in the moment the body detects prostate cancer, it
» sends the signal to the scalp to start balding!”
»
» .
??? Please read again my multiple answers. I keep addressing this issue. So, once again: if hairsite’s postulate is to be granted, then yes, AGA has to be a direct mechanism triggered to fight the disease. That’s precisely why his assumpton is false. The specification I made previously ( “balding OR NOT” ) addressed your remark perfectly.
But above all, apart from any selection oriented point (which is a bit misleading I believe because sex based selection is not to be confused with evoluton-based selection…), why would women have been spared by this necessity to cool the brain down? Many mysoginists might find an easy answer, yeah, true…
Two other points make this hypothesis a bit quirky:
- if MPB evolved from the african populations in the first placeand if evolution is stilll on its way, why is it that africans tend to exhibit lesser rates of MPB than caucasians?
- Though a complete ignorant of this theory, I doubt that a bald head might cool the brain down. In hot climates, it would rather be the opposite: hair is supposed to be calorific insulating material protecting against the UV. Don’t bald men complain of the sunburns or risks thereof they incur in summer? I think I’ve heard some of them say so.
» » “That doesn’t mean that it’s a DIRECT MECHANISM that the body uses to
» » fight the disease, as in the moment the body detects prostate cancer,
» » it sends the signal to the scalp to start balding!”
»
» ??? Please read again my multiple answers. I keep addressing this
» issue. So, once again: if hairsite’s postulate is to be granted, then yes,
» AGA has to be a direct mechanism triggered to fight the disease.
Are you NUTS, brm?? 
There is nothing in that posted abstract which suggests that AGA is a direct mechanism “triggered” to fight the disease. That’s an idea that YOU are projecting onto it yourself, and frankly, it’s a ridiculous one. Go back and read it again, CAREFULLY this time.
.
» I guess brain-cooling COULD have theoretically been the source of it.
» I was partly reacting to the idea that it’s still a legit reason for
» the trait to be continuing now, which I don’t buy.
Ok, that’s good. All I was ever really talking about in the first place was just the evolution of balding in the DISTANT PAST. Whether or not the evolutionary trend toward balding is still taking place in the current time (with much of humanity living in colder climates, and with air conditioning) is anybody’s guess.
» But MPB doesn’t seem to be the rule in many of the existing apes, right?
» So is it evolving separately? Why in the stumptailed macaques and the
» humans but not so much in the others? Would cranial size explain that?
Those are all excellent questions, and I don’t know what the correct answers are. I find it strange that those questions apparently haven’t been addressed in the medical literature on balding, or discussed on hairloss sites. One would think that just from the simple standpoint of investigating the process of evolution, it would have been a subject of great interest among scientists to tabulate just exactly which primates are susceptible to balding and which aren’t, and attempt to answer what seems to me to be the fundamental question of whether balding evolved separately in different primate species, or whether all the balding species are descended from a common balding primate ancestor.
BTW, if it does turn out that balding evolved SEPARATELY in certain primate species, it seems to me that would be rather powerful evidence in favor of the “brain-cooling” hypothesis. After all, what is the probability that that would have happened purely by accident in such closely-related species?? The one screamingly obvious connection between all primates is their more advanced brains, with (presumably) greater heat production!! 
» I see MPB as probably just a foul-up now.
»
» Maybe it had a legit brain cooling purpose when apes lived 5 million
» years ago on the African plains.
Which is ALL I’m talking about. I’m making no assumptions at all about whether or not the evolutionary pressure toward balding is continuing even in modern times.
I think the theory that MPB evolved as a way to help cool the brain is a pretty attractive one. It has a certain elegance to it. It has that “ring of truth” to it, in my opinion.
» MPB is also MUCH, MUCH less present in females.
I should point out to you here that in stumptailed macaques, females experience balding to about the same extent that males do!
Who knows? If the evolutionary pressure toward balding is indeed continuing even in modern times, maybe ALL of humanity (including females) will eventually be affected by it, in future millenia.
.
» But above all, why would women have been spared by
» this necessity to cool the brain down?
But I DON’T think that women have been spared that necessity to cool the brain down! 
As I pointed out in my previous response to cal, female stumptailed macaques experience balding to about the same extent as the males do. And my main premise for this “brain-cooling” theory would be that we are still relatively early in this evolutionary trend toward balding. If it’s continuing even in modern times (I say IF it’s continuing), I would expect ALL of humanity (including females) to be eventually affected by balding in future millenia.
» Two other points make this hypothesis a bit quirky:
» 1) if MPB evolved from the african populations in the first placeand if
» evolution is stilll on its way, why is it that africans tend to exhibit
» lesser rates of MPB than caucasians?
I don’t know that they do. I’ve seen people make that claim, but do we have any PROOF of that?
» 2) Though a complete ignorant of this theory, I doubt that a bald head
» might cool the brain down. In hot climates, it would rather be the
» opposite: hair is supposed to be calorific insulating material protecting
» against the UV. Don’t bald men complain of the sunburns or risks thereof
» they incur in summer? I think I’ve heard some of them say so.
Read the study “Beards, Baldness, and Sweat Secretion”. The experiments they did seem pretty conclusive that the lack of scalp hair assists in cooling.
.
»
» Are you NUTS, brm??
»
» There is nothing in that posted abstract which suggests that AGA is a
» direct mechanism “triggered” to fight the disease. That’s an idea that YOU
» are projecting onto it yourself, and frankly, it’s a ridiculous one. Go
» back and read it again, CAREFULLY this time.
»
» .
I can barely believe you’re serious. The direct mechanism is IMPLIED by Hairsite’s PROPOSITION: "Here I propose that progression of androgenic alopecia rather than being a risk factor is a finely tuned mechanism evolved to protect against prostate cancer “and once again, that’s the reason why his propositon seems false.
Despite your accurate STATIC knowledge of MPB, it’s not the first time I notice that your LOGICAL reasoning may be flawed. Let us only scroll a few posts up in this very thread, as cal was teling you in the middle of his point:
”» And why would someone’s brain be liable to get “hotter” as they got older?
you answered incredibly enough:
“»They don’t. What does THAT idea have to do with anything??”
Whereas it was OBVIOUS that cal meant that AGA may often break out in the 50’s or 60’s of a man’s life, leaving him perfectly untouched before. And you did not understand this obvious point… as you do not understand mine…
»
» As I pointed out in my previous response to cal, female stumptailed
» macaques experience balding to about the same extent as the males do. And
» my main premise for this “brain-cooling” theory would be that we are still
» relatively early in this evolutionary trend toward balding. If it’s
» continuing even in modern times (I say IF it’s continuing), I would expect
» ALL of humanity (including females) to be eventually affected by balding in
» future millenia.
»
It doesn’t answer the question at all. If there is no sexual feature in this phenomenon, (i.e hormones are irrelevant), why are only men affected? Both sexes should be concommitantly.
» » Two other points make this hypothesis a bit quirky:
» » 1) if MPB evolved from the african populations in the first placeand if
» » evolution is stilll on its way, why is it that africans tend to exhibit
» » lesser rates of MPB than caucasians?
»
» I don’t know that they do. I’ve seen people make that claim, but do we
» have any PROOF of that?
Proof? Do we have any proof that finasteride impairs the sexual function? Only studies. their level of credibilithy may be somewhere from 0 to …
»
» Read the study “Beards, Baldness, and Sweat Secretion”. The experiments
» they did seem pretty conclusive that the lack of scalp hair assists in
» cooling.
»
» .
Where was this study carried out? 9 out of ten: Northern hemisphere and temperate latitudes (US or Canada or…) So, Least of… PROOF;-)
» » There is nothing in that posted abstract which suggests that AGA is a
» » direct mechanism “triggered” to fight the disease. That’s an idea that
» » YOU are projecting onto it yourself, and frankly, it’s a ridiculous one.
» » Go back and read it again, CAREFULLY this time.
»
» I can barely believe you’re serious. The direct mechanism is IMPLIED by
» Hairsite’s PROPOSITION: "Here I propose that progression of androgenic
» alopecia rather than being a risk factor is a finely tuned mechanism
» evolved to protect against prostate cancer "and once again, that’s the
» reason why his propositon seems false.
And once again, you’re PROJECTING your own silly interpretation of what that means, when it says no such thing, and implies no such thing.
» Despite your accurate STATIC knowledge of MPB, it’s not the first time I
» notice that your LOGICAL reasoning may be flawed. Let us only scroll a few
» posts up in this very thread, as cal was teling you in the middle of his
» point:
» "» And why would someone’s brain be liable to get “hotter” as they got
» older?
»
» you answered incredibly enough:
»
» “»They don’t. What does THAT idea have to do with anything??”
»
» Whereas it was OBVIOUS that cal meant that AGA may often break out in the
» 50’s or 60’s of a man’s life, leaving him perfectly untouched before. And
» you did not understand this obvious point… as you do not understand
» mine…
I still see no point to what he said. Everybody knows that balding can begin at many different points in a man’s life. The error you’re probably making is that you’re assuming that the loss of hair is directly CAUSED by an overheated brain (much like your erroneous interpretation of what that prostate cancer hypothesis means), but that’s not the case. The “brain-cooling” hypothesis assumes that balding happened more INDEPENDENTLY of brain over-heating than what you think it does. Let me try to explain it to you in simple terms that even YOU can understand: a chance mutation presumably occurred hundreds of thousands of years ago in Early Man. That chance mutation just ACCIDENTALLY caused scalp hair follicles to become sensitive to androgens, and fall out as a result, causing the humanoid to become bald.
But an amazing SIDE EFFECT of that chance mutation was that it also caused those early humanoids to have COOLER BRAINS, which was an advantage to them, there in hot, sweltering Africa! Through the process of natural selection, those early humanoids who had that chance mutation thrived, and went on to out-compete with the others who didn’t have that advantage. Eventually, the ones with the “balding gene” (I use the term loosely) completely dominated the population, and EVERYBODY eventually had that trait, even if they didn’t all develop balding at the exact same age! :surprised:
So I hope you and Cal are starting to see the Big Picture here: balding developed and thrived as an indirect counter to over-heated brains, but that doesn’t mean that over-heated brains DIRECTLY cause balding. It most certainly does NOT imply that men who start balding later in life must have hotter brains as they age! 
That’s just a childish interpretation of the “brain-cooling” theory.
.
» It doesn’t answer the question at all. If there is no sexual feature in
» this phenomenon, (i.e hormones are irrelevant), why are only men affected?
» Both sexes should be concommitantly.
I already explained to you before in plain English that we’re still relatively early in the phenomenon, which means that hormone levels ARE still relevant. But if there is still an evolutionary pressure toward balding even in modern times, then I expect more and more people (even females) to slowly evolve hair follicles which are more and more sensitive to androgens, so that eventually even females will be balding, just like they do in stumptailed macaques.
» » I don’t know that they do. I’ve seen people make that claim,
» » but do we have any PROOF of that?
»
» Proof? Do we have any proof that finasteride impairs the sexual function?
» Only studies. their level of credibilithy may be somewhere from 0 to …
So your answer is NO, we have no proof.
» » Read the study “Beards, Baldness, and Sweat Secretion”. The
» » experiments they did seem pretty conclusive that the lack of
» » scalp hair assists in cooling.
»
» Where was this study carried out? 9 out of ten: Northern hemisphere and
» temperate latitudes (US or Canada or…) So, Least of… PROOF;-)
Is THAT the best you can do?
.
Bryan –
As for the ideas about whether MPB is currently being selected for or against, I find the balding female stumptails fact very interesting.
Like I said, I have a hard time believing that MPB in humans could have really evolved in just the male gender from the beginning. Male/female head size in relation to the rest of the body aren’t much different (heck, we’ve arguably got even BIGGER heads in females, proportional to the rest of the skin & body size!). I think Darwin would demand something like baldness in both genders if it demanded it in one of them.
So,
Between the baldness in the female stumptails, and the lower MPB incidence in human females, and the Ludwig/Norwood patterns in human females (making early MPB less visually-obvious even when it DOES appear), and the fact that at least a good portion of current humans (both genders) don’t find it as attractive as a full head of hair . . .
I think this paints a strong picture. I see a trait that may have been totally functional & prevalent in both human genders long ago, but now it’s being selected against in recent times.
This selection has already squeezed it out of most of the female (breeding-age) population by a wide margin. And everyone on here knows there is at least some steady pressure to squeeze it out of male population too.
» » I can barely believe you’re serious. The direct mechanism is IMPLIED
» by
» » Hairsite’s PROPOSITION: "Here I propose that progression of androgenic
» » alopecia rather than being a risk factor is a finely tuned mechanism
» » evolved to protect against prostate cancer "and once again, that’s the
» » reason why his propositon seems false.
»
» And once again, you’re PROJECTING your own silly interpretation of what
» that means, when it says no such thing, and implies no such thing.
»
No you’re just projecting your own inability to draw a correct conclusion from a given hypothesis.
» » Despite your accurate STATIC knowledge of MPB, it’s not the first time
» I
» » notice that your LOGICAL reasoning may be flawed. Let us only scroll a
» few
» » posts up in this very thread, as cal was teling you in the middle of
» his
» » point:
» » "» And why would someone’s brain be liable to get “hotter” as they got
» » older?
» »
» » you answered incredibly enough:
» »
» » “»They don’t. What does THAT idea have to do with anything??”
» »
» » Whereas it was OBVIOUS that cal meant that AGA may often break out in
» the
» » 50’s or 60’s of a man’s life, leaving him perfectly untouched before.
» And
» » you did not understand this obvious point… as you do not understand
» » mine…
»
» I still see no point to what he said.
How dishonest of you! You now pretend you simply contended with his point whereas you had simply not understood the relationship he was establishing… Glaring flip-flop.
Everybody knows that balding can
» begin at many different points in a man’s life. The error you’re probably
» making is that you’re assuming that the loss of hair is directly CAUSED by
» an overheated brain (much like your erroneous interpretation of what that
» prostate cancer hypothesis means), but that’s not the case.
I’ve never said or thought this… Once again you did not understand…
»The “brain-cooling” hypothesis assumes that balding happened more INDEPENDENTLY
» of brain over-heating than what you think it does. Let me try to explain
» it to you in simple terms that even YOU can understand: a chance mutation
» presumably occurred hundreds of thousands of years ago in Early Man. That
» chance mutation just ACCIDENTALLY caused scalp hair follicles to become
» sensitive to androgens, and fall out as a result, causing the humanoid to
» become bald.
»
» But an amazing SIDE EFFECT of that chance mutation was that it also caused
» those early humanoids to have COOLER BRAINS, which was an advantage to
» them, there in hot, sweltering Africa!
This remains very dubious, that a bald head exposes the brain to the heat of the sun less than a hairy scalp does…
» » It doesn’t answer the question at all. If there is no sexual feature in
» » this phenomenon, (i.e hormones are irrelevant), why are only men
» affected?
» » Both sexes should be concommitantly.
»
» I already explained to you before in plain English that we’re still
» relatively early in the phenomenon, which means that hormone levels ARE
» still relevant. But if there is still an evolutionary pressure toward
» balding even in modern times, then I expect more and more people (even
» females) to slowly evolve hair follicles which are more and more sensitive
» to androgens, so that eventually even females will be balding, just like
» they do in stumptailed macaques.
»
» » » I don’t know that they do. I’ve seen people make that claim,
» » » but do we have any PROOF of that?
» »
» » Proof? Do we have any proof that finasteride impairs the sexual
» function?
» » Only studies. their level of credibilithy may be somewhere from 0 to
» …
»
» So your answer is NO, we have no proof.
What I mean is that the word PROOF should be the last to be used here. I would not be so mean as to ask you for any proof of your theory. You obviously have none and we don’t expect any. You’re just exposing a particular point with no PROOF and we somehow contend with it with no PROOF either. There’s no one to blame for it.
»
» » » Read the study “Beards, Baldness, and Sweat Secretion”. The
» » » experiments they did seem pretty conclusive that the lack of
» » » scalp hair assists in cooling.
» »
» » Where was this study carried out? 9 out of ten: Northern hemisphere and
» » temperate latitudes (US or Canada or…) So, Least of… PROOF;-)
»
» Is THAT the best you can do?
No, far from it. Weird question…:waving:
» » So your answer is NO, we have no proof.
»
» What I mean is that the word PROOF should be the last to be used here.
Why is that? It’s an eminently testable question. It’s either true or false, and scientists certainly have the ability to find out the correct answer.
» I would not be so mean as to ask you for any proof of your theory. You
» obviously have none and we don’t expect any. You’re just exposing a
» particular point with no PROOF and we somehow contend with it with no
» PROOF either. There’s no one to blame for it.
I’m not sure what you mean. There’s obviously no proof for the “brain-cooling” theory, but it’s certainly possible to determine the incidence of balding in the African population.
.