

Men age faster 'because of Stone Age sex' - amichail
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/10/17/scisex117.xml

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ced
Not very convincing. 1\. Why do men reach puberty later than females? 2\. Men
can have children even when they're very old, women can't. This should promote
longer lifespans.

Here's another hypothesis. Quoting the Wikipedia article on the Medawar theory
of ageing:

"Nature is a highly competitive place, and almost all animals in nature die
before they attain old age. Therefore, there is not much motivation to keep
the body fit for the long haul - not much selection pressure for traits that
would maintain viability past the time when most animals would be dead anyway,
killed by predators or disease or by accident."

This is particularly true for men, who were (and still are, to an extent)
usually doing more dangerous jobs than women. Thus, they die from accidents or
predation earlier, so there is less selective pressure for genes that promote
healthy organs in old age.

Another possible scenario: there is more variation in male traits than in
females, and age is more than linearly dependent on these traits. Thus, even
if E[X] is the same for males and females, for some trait X, the average age
E[X^n] will be lower for males.

Evolutionary biology is full of reasonable-sounding explanations for just
about anything. As far as I can tell, Occam does not often apply,
unfortunately.

~~~
timr
Don't slight the entire field of evolutionary biology just because you don't
like what you read in a tabloid newspaper. I hope you realize that there's
usually a bit more to these stories than you'll find in a four-paragraph
newsprint blurb.

~~~
jsmcgd
Point of interest: The Telegraph is not a tabloid but a broadsheet.

~~~
falsestprophet
Whatever the case, it is a rag.

------
mechanical_fish
Who knows what this study says, let alone how valid it is? Like just about
every newspaper article about science, this Telegraph article absolutely
sucks.

Here's what was the original journal article was supposedly about:

"...the difference in life span between males and females... grows in direct
proportion to the degree to which an animal's society is polygynous."

Great! These folks have apparently plotted a graph, where X is an animal
society's "degree of ploygyny" and Y is the lifespan difference. The shape of
that graph is the entire point of this study. It would be interesting to see
it.

How many of the data points from that graph made it into the newspaper? Half
of one data point. We learn that the male-female lifespan difference among
modern humans is 5 years out of 80. (This is, of course, probably the least
useful piece of data in the entire dataset, because modern humans live a
lifestyle utterly different from that of all previous _humans_ , let alone
most other animals.)

The scientists might well have data about polygyny in humans, but it's not
shown here. They certainly have data about polygyny and lifespans in other
creatures -- but it's not shown here. If the damned reporter had just given us
the numbers for _one creature_ \-- dare I suggest the chimpanzee? -- we would
know a lot more about the original study and how much it applies to humans.

But no! Instead the article tells me that women live longer than men (duh!)
and that modern human societies tend more toward polygyny than toward
polyandry. (Double duh.) Gee, thanks.

Sorry about the rant, but this sort of thing is intensely frustrating to me.
People wonder why the public doesn't understand how science works. Perhaps one
reason is that _the average person never sees any actual data_.

------
whacked_new
In some ways this is a chicken and egg problem, and the conclusions in this
article are not satisfactory.

[http://www.hno.harvard.edu/gazette/1998/10.01/WhyWomenLiveLo...](http://www.hno.harvard.edu/gazette/1998/10.01/WhyWomenLiveLon.html)
"Studying people who live 100 years and more leads Harvard researchers to
conclude that menopause is a major determinant of the life spans of both women
and men."

[http://www.sciencedaily.com/releases/2006/05/060526083618.ht...](http://www.sciencedaily.com/releases/2006/05/060526083618.htm)
Study about birds, but interesting: "Elevated testosterone levels increased
activity--possibly attracting more predators--made the male, dark-eyed juncos
more susceptible to disease and shortened their lifespan."

And I won't go into estrogen.

------
staunch
I have a totally uneducated hypothesis that women are more prone to casual
bisexuality and it's inherently more acceptable because they were kept in
harems in prehistoric time.

~~~
falsestprophet
That does not make a great deal of sense from an evolutionary perspective. For
bisexuality to be selected for in women, it would have to confer an
evolutionary advantage. I would guess that it simply has not been selected
against because it does not confer a great disadvantage.

However, tolerance for homosexual acts between men seems to be strongly
selected against. Creating sperm is expensive and wasting them with a man is
not to your advantage. It was also important for men to be highly focused on
interfacing with females; females could be apathetic and reproduce, because
they didn't really have a choice.

~~~
brenda90210
> _However, tolerance for homosexual acts between men seems to be strongly
> selected against_

Actually historically there were numerous instances of largely-homosexual
civilizations. Just look up the true story behind the movie 300.

> _Creating sperm is expensive and wasting them with a man is not to your
> advantage._

I think you completely forgot about masturbation, which pretty much destroys
that entire line of argument ;) Males "waste" sperm on a constant basis. :)

> _It was also important for men to be highly focused on interfacing with
> females_

Actually in many societies men were NOT focused on social interaction with
females, a trend that continues to this day especially in certain religious
countries. Interaction was and is often limited to reproduction, with gender
segregation in social roles (the men spend most of their time with other men
while the women spend most of their time with other women and children).

It really doesn't take much effort at all to get a female pregnant. The _vast_
majority of effort is in child-rearing, not procreation. Homosexuality
actually confers some advantages, such as:

\- Male bonding, leading to more effective teamwork, which is a huge advantage
in small tribal societies;

\- Exclusively-homosexual males don't compete for females yet can still lend
their muscle to protecting the tribe.

In a small tribe, competition for females can lead to infighting which will
put the whole group at a disadvantage to a neighboring tribe that has the same
gender split but in which most of its males are homosexual. (Effeminate
homosexuals tend to be much less common than non-effeminate ones, which is why
so many gay males can fly under the radar.)

~~~
falsestprophet
>Actually historically there were numerous instances of largely-homosexual
civilizations. Just look up the true story behind the movie 300.

This is anecdotal evidence. Isolated societies that practice homosexuality do
not offer a sound argument against the general trend. Note that you can only
think of a few examples.

>I think you completely forgot about masturbation, which pretty much destroys
that entire line of argument ;) Males "waste" sperm on a constant basis. :)

Recall that is is a conversation about bisexuality and homosexual behavior,
not homosexuality which is obviously not evolutionarily helpful to a
homosexual man (although there are theories that account for the genes that
increase the liklihood of homosexuality having an evolutionary advantage for
the women that carry them). Evolution is not a boolean question, traits
propagate according to their relative success. Men who only want to have sex
with women are more likely to deposit more sperm into women than men who
deposit sperm wherever it fits. Masturbation would work against both
populations.

>Actually in many societies men were NOT focused on social interaction with
females.

I did not say interacting with women. Lots of people interact with women
without reproducing. I said 'interfacing,' which was meant as a euphemism for
fucking. I will spare you the confusion of further euphemisms. Son, people
fuck everywhere.

~~~
brenda90210
> _This is anecdotal evidence._

Actually it's well-established. The best-known example is ancient Greece.
Here's a general roundup of some historical figures: Socrates, Alexander the
Great, Lord Byron, Edward II, Hadrian, Julius Caesar, Michelangelo, Donatello
and Christopher Marlowe.

> _Recall that is is a conversation about bisexuality and homosexual
> behavior,_

The conversation is about whatever people discuss. Funny to see you try a
dodge when I completely skewer your "sperm is expensive" faux-pas! :)

> _I said 'interfacing,' which was meant as a euphemism for fucking._

Yes, your example is incorrect, as societies in which men were _not_ "highly
focused on interfacing with females" still managed to keep the birth rate up.
Cf. 300.

> _not homosexuality which is obviously not evolutionarily helpful to a
> homosexual man_

Sure it can be -- especially when it's the norm. It's not even disadvantageous
to his genes as long as he's not _exclusively_ homosexual. Even if he were,
from his genes' perspective, he can still fulfill a useful role by protecting
and benefitting his close kin, who have a lot in common genetically.

Homosexuality is rampant in the animal kingdom. Numerous studies have
discovered this surprising result. In humans it persists despite widespread
modern cultural condemnation, so it's a bit of a sticky issue. It's not as
simple as a blanket "selected for" or "selected against" situation. There's no
such thing as universal fitness; just adaptations that are useful in a
particular time and place.

------
davidw
I'm not sure I buy it. Most hunter gatherer societies that still exist don't
really have harems. Maybe two or three wives in some cases, but my
understanding was that big harems didn't really come about until the dawn of
agriculture.

~~~
timr
The dawn of agriculture was somewhere around 10,000 years ago. Even assuming
that you're right, that's (conservatively) over 300 generations of polygamy.

~~~
davidw
Sure, but their argument centers around the stone age, which _ends_ with the
development of agriculture.

~~~
timr
The only place the stone age is mentioned is in the first paragraph of the
newspaper blurb. The study itself is much more limited, and says only that
sex-determined differences in lifespan appear to correlate with polygyny
across a large number of species.

~~~
davidw
Do you have a link to the original somewhere? What I've seen elsewhere (I
think it was Jared Diamond's The Third Chimpanzee, which is probably out of
date at this point) is that male/female size ratio is also an indicator of
polygyny, and that in comparison with other species, yes, humans are, but not
to the large degree that some other animals are. That would fit in with the 2
or 3 wives sometimes seen in the hunter/gatherer societies more than big
harems.

------
sabat
1- This doesn't belong here.

2- Reductive, over-generalized and oversimplified.

3- Men don't age faster. They often die slightly younger (more like 3 years
rather than the stated 5). Men age more slowly and gracefully (if you have to
generalize). Don't believe it? Take a look around you.

