Re: Sperm Wars

From: Stevan Harnad (
Date: Sat Nov 08 1997 - 20:44:25 GMT

Alex, you did a great job in your summary: My comments here are
mostly on the text, not on your report, which was brilliant. - S

On Sun, 2 Nov 1997, ALEXANDRA BECK wrote:

> Women hide their fertility so her partner can not guard her so
> intensively, therefore having control over who inseminates her.

Without risking the loss of a regular partner in rearing her
and (presumably) his offspring.

> But also her self. Not being able to predict the best time to
> inseminate, routine sex allows fertile sperm to always be inside her.
> ^ what is best for one partner is very often not best for the other ^
> pg10.

This means that even for the female the outcome of a sperm war is more
beneficial if the competing sperm are left to fight it out, rather than
having the contest decided entirely by the female.

> S3:Flowback (a mixture of seminal fluid and mucus) is one of a
> woman^s

This passage does not seem to have come through; nor did anything for

> Males and females therefore, inherit a predisposition to find [oral
> sex] stimulating.

Yes, on the sweet tooth model. But be careful about building too much on
such an obvious variant of the standard sex act: If someone is
stimulated by a commercial vibrator, this is not likely to be because
20th century sex gadgets are tapping into something that was important
for survival in the EEA.

> There is no danger of [a woman's] being
> tricked into raising a child which is not hers. This might mean that
> infidelity is slightly less of a threat to a woman than it is to a
> man.

Yes: The woman risks losing a necessary collaborator in rearing her
children if he finds another partner he prefers more; but the man
risks rearing the offspring of another if she has sex with another,
and this is the worst genetic no-no of all. So both the conditions under
which man and women feel sexual jealousy and the intensity of it should
differ for them.

> CH5 S12: Male masturbation or shedding sperm is an important part of
> reproductive success. Masturbation is a way in which a man can tailor
> his next insemination. Thus, allowing the man maximum flexibility in
> adjusting his sperm army according to the risk of warfare.
> Subconsciously the brain plays a major role in the anticipation of
> insemination.

This is one to think about, since most of the variation Baker
interprets as unconscious sperm regulation already follows from two
very simple parameters: (1) time since last ejaculation and (2) degree
of novelty and attractiveness of the partner. Maybe the selfish genes
needed nothing more specific than that.

If I didn't tell it in class, then here is a good-time to explain the
"Coolidge Effect." When female rats are in estrous (in a lab) then
the experimenter can keep giving her new partners, one after the other, and
she will not tire from copulating with each. It is the male who tires,
and so must be removed and followed by a new male if the copulation is
to continue. On the other hand, when the male copulates till exhaustion
with a female, removing her and providing an new partner keeps restoring
his interest.

This effect (on the male) has gotten the name of the Coolidge Effect
from a joke about US President Calvin Coolidge. He and his wife are
visiting a chicken farm and are being shown around separately by their
hosts. Upon seeing a rooster, Mrs. Coolidge asks: "How often does the
rooster mate?" The reply is "Nine or ten times a day, Ma'am." So Mrs.
Coolidge asks: "Would you mind going to tell that to the President?"

When the President is given the message from Mrs. Coolidge he asks:
"And with whom does the rooster mate 9-10 times a day?" "With a
different hen each time, Mr. President." "Would you mind going to tell
that to Mrs. Coolidge?"

> Once
> the brain begins to anticipate infidelity, the body increases the
> masturbation rate, thereby producing and maintaining a young, fitter
> rich ejaculation in his tubes (no more than 24 hours old). A man
> therefore need to hide his masturbation routine from his partner.

I wasn't very convinced by this part of the book. Again, time and degree
of arousal seem to be as good a fit to the data as Baker's more involved
unconscious computation.

> The more men and woman drink (alcohol) the more they seek sex, or at
> least the less they resist it. Yet in reality the more men drink the
> less likely they are to have it (brewers droop). Women on the other
> hand are just less likely to enjoy is, due to decreased sensitivity of
> the clitoris.

Hard to see the relevance of this, assuming that there was no alcohol in
our EEA!

> S15: There are three different types of infertile menstrual cycles, and
> most women

Something missing here too: Alex, do you have a copy of the whole
report, including the missing bits?

> S21: Orgies are useful to the woman to create sperm warfare. The winner
> having the most successful sperm.

Surely it's not orgies per se that are useful to the woman (assuming
that the Baker is right to at least some extent about sperm
competition): what do the gain from having their partners have many
other partners. Surely the only thing that is useful to a woman (again,
if the basics about the theory of sperm competition are right and
relevant) is that she herself should have multiple partners (of her
choice) within a time window that allows the sperm to fight it out
within her body.

> The man with the best chance of winning would be the one
> who timed his own inseminations, to interfere most with other men^s
> inseminations and best judged when and when not to thrust.

I, for one, cannot see how things can be orchestrated thrust by thrust,
whether consciously or unconsciously. I don't believe the Blind
Watchmaker had such fine tuning to work from in the EEA, let alone in
our present environment.

> The woman^s
> role, in trying to further their own reproduction success, was to give
> each man maximum opportunity to prove himself- and maximum chance to
> make mistakes.

I am willing to believe (alas) that ours is a sperm-competing species
rather than a faithful, monogamous, lifelong pair-bonding species:
Supposedly, just the relative male gonad to body size ratio of our
species -- compared, say, to the gonads of a male turtle dove --
already warns us that we weren't lovebirds in our EEA either.
But surely accepting that does not commit us to believing these thrust
by thrust analyses of the "unconscious calculations" that allegedly
underlie them.

> CH8 S22: ^Of all aspects of human sexuality, the female climax has
> probably been the most enigmatic.^ How do climaxes influence a woman^s
> reproductive success depending on the situation in which they occur? A
> woman feels like a climax whenever it feels it will enhance her
> reproductive success.

"It" feels is right, since it's certainly not SHE who feels it!
I for one think that unconscious calculations at this level of
specificity are just bioscience-fiction. The factors determining when a
woman feels like a climax are (in order of importance): (1) Her
current capacity to climax, (2) the current stage of her cycle, (3) how
sexy she finds her partner, (4) the time since her last climax (though
I'm less sure about this one: unlike in males, timing may cut both
ways, or perhaps be less relevant in females), (5) how novel her
partner is, and (6) how adept her partner is.

> changes the strength of a woman^s cervical
> filter-most often strengthening it.

You didn't define "cervical filter" for kid-sib, who is brilliant
but completely ignorant in sexual matters...

> A sexual episode is actually a contest between the man and
> the woman. Each is forever trying to outmanoeuvre the other into doing
> something that is against their body^s interests.

And here we were, naively thinking it sometimes had to do with love, or
even just lust...

> If a man can stimulate the woman to an climax then she knows
> that he has had some past experience. This tells her that other women
> have also found him attractive. Thus, mixing her genes with his could
> produce attractive offspring who are also attractive to the opposite
> sex, hence increasing her reproductive success.

That sounds a little more believable to me. How about the rest of you?

> S28: Rough and tumble play is a common element in the courtship of
> humans and many other animals. Date rape victims were three times more
> likely to resume their relationship if the man succeeded than if he
> failed.

Or it was those who were least inclined toward a long-term relationship
with that partner who put up the biggest fight.

> Men are descendants from urgent ancestors.

sexually "persistent" maybe, rather than "urgent"?

> On average, men who are physically
> able to overcome the final defences of a female and achieve
> insemination produce more offspring than those who don^t.

That's if you average across the honest courtship matings and, say,
multiple rapes in wartime.

> So if a woman
> wants her son to have these characteristics she has to set tests. She
> therefore has to resist his advances. This can become rather
> dangerous.

I agree. In fact, couldn't just the same just-so story be told in
reverse? The women who successfully resist coercion are fitter because
they exercise choice in selecting their partners, rather than
succumbing to force; and their daughters will inherit this fitness.

Here is a potential exam question, so you may as well think about it:
Take some traits or strategies for which you have heard the
sociobiological explanation of why they are adaptive, and give an
equally good explanation for why the trait/strategy could go in the
opposite direction, as above.

> Condoms do not spoil a woman^s subconscious rationale for
> having routine sex, but they do spoil a man^s. She can still hide her
> fertile phase. Yet a man^s sperm do not take up residence. Thus, men
> are consciously and subconsciously not so enthusiastic about the
> condom.

This is another one that's just as easy to turn on its head: women have
much more to lose from unwanted inseminations, so they should be much
more committed to condom use. (Actually, that was not a reversal but an
alternative rationale for the same outcome.)

> Why then do men
> wear condoms? Well, one possibility is that they are fooling their
> subconscious body. The evidence for this is that they still go through
> the same procedures as when they haven^t used a condom e.g. topping
> up.

Of course, this is just as easily explained by timing/novelty/excitement
parameters, with no need to take any evolutionary position on men's
attitudes to the long past EEA-appearing condom.

> If men actually did reduce their reproductive success
> through the use of condoms, things should change over the generations

Indeed they should (if condom-use should happen to be under genetic
control -- something I think could only have happened if there had been
condoms in our EEA); but then again, if it helped in successful family
planning and prevented disease, AND there was a genetic disposition to
wear them, then the change would be toward using them more rather than

> Increasing
> even further if you do not withdraw, yet women aren^t that gullible
> twice!

In the long run, this strategy could be successful even if the man got
away with it only once with any one woman: if he does it often, he will
"succeed" in some non-zero percentage of his attempts.

> CH10 S30: Women will on average sleep with 8 men whereas men on average
> will sleep with 12.

The question is: are those numbers normally distributed? Or are they
actually averages across a large 1-partner population plus a small VERY
many partner population? (I expect not, but one must be critical about
statistics like these.

> Homosexual behaviour does not reduce the
> likely hood of reproducing, quite the contrary.

I was sceptical about the data here. Again, there might be many men who
experimented with homosexuality, perhaps when they were young, but
grew into ordinary heterosexuals. If they are reckoned among the
"homosexuals" with the reproductive success, then no wonder. On the
other hand, there are the true exclusive (or almost-exclusive)
homosexuals who are really a different population and may not reproduce
much at all.

> Homosexual behaviour is not peculiar to humans. 6% of males
> in Europe and the USA experience homosexual behaviour.

Oh, are European and USA men not human then?

> The vast
> majority of homosexuals show bisexual behaviour(80%).

One needs to see the stats. As I said, it's stretching the term
"bisexual" if one counts the juvenile and adolescent experiments
with same-sex acts as bisexuals. So that may account for 75 out
of the 80% above. The other 5% may be true homosexuals experimenting
with hetero sex, or perhaps that 5% corresponds to the true bisexuals.
In any case, these data need to be analysed much more closely before
this conclusion is to be believed.

> If there is a group of
> women together and they are not ovulating they will tend to synchronise
> their periods, yet if the women are ovulating they tend to
> desynchronise. Trying to hide there fertile phase from their partner.

Some doubt was expressed about this in class. (Those of you who
want to do really well on the sperm competition question on the
exam, have a look at the Baker & Debellis book mentioned in the

> If we
> can consider prostitutes as a genetic predisposition then they should
> have the same likelihood as other woman at successfully reproducing. If
> it is not genetic then any woman could become a prostitute and have a
> higher level of reproductive success.

Poor people also have better reproductive success; presumably poverty is
not genetic, so any of us could use that strategy to increase our
reproductive success.

> A woman is more likely to conceive
> from rape than routine sex, the trauma of rape actually stimulates
> ovulation, it also involves the collection of more sperm because of the
> high numbers of sperm injected into her- like infidelity. It is
> therefore a successful reproductive strategy for women.

Alex, it's time for some critical analysis here! You can't drop a
bomb-shell like that an just be the message bearer!

  "A woman is more likely to conceive from rape than routine sex"

Perhaps a woman is more likely to conceive from nonroutine sex than
routine sex.

  "the trauma of rape actually stimulates ovulation"

Trauma stimulates ovulation?

Surely it's easier to tell a just-so story about the reproductive
DISadvantages of rape (no chance to exercise female choice, unlikely to
lead to help in child-rearing, danger to life and limb, danger of

Theft and murder are probably also good reproductive strategies, because
you can support many wives with the stolen goods. Maybe the EEA, being
prior to culture and law, was very violent, with everyone trying to take
things by force when they could get away with it.

> There
> are four categories of women: those who can achieve all types of
> climax, those who are programmed to avoid one kind of climax, those who
> climax every time they have penetrative sex and finally those who never
> have climaxes. All these categories should all reproduce equally well.

So maybe there is no need to tell a Darwinian tale about the
reproductive utility of the climax.

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