Re: Masturbation Spandrels?

Timothy Perper/Martha Cornog (
Fri, 20 Jun 1997 13:56:03 -0500

Message-Id: <>
Date: Fri, 20 Jun 1997 13:56:03 -0500
From: (Timothy Perper/Martha Cornog)
Subject: Re: Masturbation Spandrels?

>Reading recent traffic prompts the following, not entirely light hearted
>Question 1
>Is masturbation a genetic spandrel or not: i.e. is it a by product of the
>evolution of opposed thumbs and hands capable of delicate manipulation?
>TP/MC may have an answer.
>Question 2
>Regardless of how it propogates is the masturbation taboo an example of a
>memetic spandrel?

These are VERY good questions, and -- of course - equally hard to answer.

We've been trying to find cross-species references to masturbation, but so
far without much success. That, we suspect, is due more to the reluctance
of various field biologists and ethologists to study such things than to
its absence. I (TP) know from work I've done with reproductive behavior in
rats that male rats will "spontaneously" ejaculate if they are deprived of
access to females; this is probably akin to the Baker and Bellis notion
that masturbation is adaptive for eliminating older sperm.

However, when it comes to human evolution and human behavior, then the
"spandrel" question does emerge. There is a charming story coming from
the old days of sex education concerning a young person speaking to a
pastoral advisor about masturbation, and being told that it was, if not
sinful, then really not right and so on and so forth. "But," said this
young person, "the arms are just long enough to reach!"

And indeed so. One *can* invent adaptationist arguments for why the arms
are "just long enough to reach," but, for the individual, sexual
manipulation of one's own and one's partner's body seems to emerge as a
"discovered" behavior. That means that individuals discover that they
*can* do something, but in turn the implication is that the body *enables*
those behaviors. This is now a major theoretical issue -- to what extent
does the *discoverability* of hand-body activity represent a biological
selection pressure driving the evolution of the hand?

For example, when we say that human evolution centered on tool making and
tool use, the observtion seems accurate enough at the phenomenological
level. However, tool making requires a complex social-cultural background
pool of information (memes, if one likes) WITHOUT WHICH the human hand is
really quite useless. So the evolution of the opposable thumb can be
explained only by reference to the increasing importance of socially and
culturally transmitted information.

In the view of a moralist, the idea is that hand-eye-thumb coordination
evolved for purely *functional* reasons -- making tools and so forth. It
then follows that *other* uses -- including all the sexual uses human
beings make of their hands -- are a kind of incidental and perhaps even
nasty by-product: a morally bad spandrel, so to speak.

For what it's worth, MC and I rather doubt it. The reason is that
sexuality is of course *directly* related to reproduction, a truism so
obvious that one can miss its implications. Still working within an
adaptationist framework, we can reason that any use of the hands -- by a
male OR a female -- that arouses oneself or one's partner will enhance the
pleasure of sex, and therefore serve as a proximal reinforcing mechanism
for wanting to engage in sex.

In the recent few years, work on the pygmy chimpanzee -- the bonobo -- has
radically altered our views of the sexuality of the higher primates.
Bonobos have very high levels of sociosexual interaction, which, it has
been argued by de Waals and by Kano, for example, is essential for
maintaining bonobo society. So we know that sexuality can play large roles
in primate social organization, providing at least an analogue to what
human evolution may have involved.

Curiously, now one encounters one of the biological spandrels that Gould
mentioned in his book. He argued that one cannot use adaptationist
arguments to explain the evolution of the clitoris in women; it is, in
Gould's view, only the homologue of the genuinely functional organ, the
penis. A while ago, a lengthy discussion on just this topic broke out on
the newsgroup. I argued that Gould was in fact wrong in
his interpretation.

It can be claimed that the extreme sensitivity of the male and female
genitalia far exceeds any reasonable level expected if these organs were
solely intromissive and receptive. Instead, one can suggest that during
human sexual evolution, mechanisms evolved that *sensitized* the genitalia
to the "delicate manipulation" you mention. Now, this idea is much more
than merely imputing a kind of sexual hedonism to our ancestors. Instead,
it suggests that sexual pair-bonding -- erotosexual bonding, if you like --
was a very important aspect of the evolution of those stable male-female
reproductive bonds that can exist in what we today call the family (this
idea is not original with me, of course; it has a long pedigree in
physical anthropology).

To be sure, sexual reproduction can occur without such things -- even rape
can make a woman pregnant -- but the issue of proximal motivations arises.
If the two actively *enjoy* their mutual "delicate manipulations," then
such enjoyment does make it likely that they will want to do it again and
again and again. (Again, the idea is hardly original with me; it comes,
among other places, from the great sexuality researcher Frank Beach.) So,
motivation towards intercourse -- seemingly such a simple thing -- actually
entails the existence in humans of pleasure/bonding mechanisms that glue
the couple together.

The existence of the clitoris, then, is the female counterpart not of an
intromittant organ useless in females, but of the pleasure and arousal
machinery of the male's anatomy. There is a reciprocity of pleasure and
arousal -- or there *can* be -- that makes the clitoris much more than
merely a functionless phallic rudiment.

What then of masturbation? Given the known correlations between decreased
intercourse and decreased masturbation so typical of erotophobia (I am
referring to Fisher and Byrne's work), it would seem quite possible that
masturbation by both sexes is a form of practice or even self-learning that
*assists* the success of later intercourse.

Now, of course, enters a long tradition of anti-masturbatory ideologies.
Adherents of one anti-masturbatory ideology claim that masturbation is the
"wrongful" use of the genitalia, and wastes sperm into the bargain. (And
such people are morally horrified by the possibility that masturbation may
have a functional relationship to success in intercourse.) However,
curiously enough, the same Roman Catholic tradition has never quite been
clear that *female* masturbation is such a terrible thing. One reason is
the traditional belief -- false though it may be -- that in order for a
woman to become pregnant, she too must "emit her seed." This phrase, which
comes from a number of medieval and later sources (see Brundage, 1987),
presumably refers to female vaginal lubrication plus, possibly, the
so-called "female ejaculation" described by recent researchers like Whipple
and Perry. Of course, it is an empirical fact that "delicate manipulation"
of the woman's genitals by both the man and by the woman will produce just
such female lubrication and arousal.

Recent literature from sex therapists trying to teach and counsel
anorgasmic women very much stresses the role of masturbation, although it
is sometimes euphemized into phrases like "self-pleasuring." From these
sources, there does not seem to be much doubt that female genital
self-touch *does* increase the woman's pleasure and therefore her desire
for sexual contact with a partner.

Unfortunately, I think, the usual approach to problems of male sexual
inability have focussed nearly solely on the medical-anatomical approach
("If it doesn't work, get it fixed by a doctor"). However, some of the
books we cited in the discussion with Lynch center on male
"self-pleasuring" and also stress how important it is for the man to "know"
his own body when engaged in partnered sex.

So far, I have of course been stressing the adaptationist scenario, or at
least indicating ways in which morally very significant issues may lead to
discussions of sexual and reproductive functionality. If we do adopt that
broad position, then in very general terms one can put forth some ideas
about how these spandrels and self-discovered behavior patterns may have
evolved. In an ultimate sense, the biological evolution of the genital
sensory tracts in both males and females were probably driven by enhanced
reproduction, but there is considerable layering, if I may use the word, of
cultural evolution on top of such demographic issues.

One issue, it seems to me, centers on how cultural processes and cultural
evolution deal with "discovered" behavior patterns like masturbation. As I
said, the body enables one to discover the genitals ("The arms are just
long enough to reach!"), but such a discovery is not *neutral* socially or
culturally. As part of a quite general pattern in which society concerns
itself with individual sexual behavior, society also concerns itself with

Of course, we need to replace that generality -- which personifies
"society" -- with detailed knowledge of how parents, religious advisors,
teachers, and peers all deal with male and with female masturbation. Here
one reaches the complex and rich tapestry of beliefs about masturbation
that we mentioned briefly during the discussion with Lynch.

So, in rough outline, the layering seems to involve a possible biological
basis for genital sensitivity that may have evolved in the context of
ancestral pair-bonding and proximal pleasure-generating and
pleasure-seeking mechanisms. This, presumably, connects to increased
reproduction. But individuals also self-discover their genitals and the
pleasures they offer. So individuals, with all their usual variation in
temperament, personality, and the like, have a large role. Then, external
to the individual is the collectivity of beliefs, ideologies, laws, and
customs passed along by parents, peers, teachers, religious authorities,
and others. In that domain, ideas and practices (memes if one prefers)
have their *own* evolutionary dynamics.

It is a complex, but not, I think, unanalyzable mix.

I've focused more on the first question, but the second -- whether
masturbation is a cultural spandrel -- is also very significant!

I've left out all the references, mostly because this literature is so
huge. Unfortunately, there seems to be no single place all this material
is collected, but I'll be pleased to share with anyone the references that
we have gathered on these topics. Probably the best source for medieval
sexuality and the idea that the woman must "emit her seed" is

Brundage, James A. 1987 Law, Sex, and Christian Society in Medieval
Europe. Chicago: University of Chicago Press.

It is long (over 650 pages), exquisitely referenced, and magisterial in its
coverage and knowledge.

There doesn't seem to be a good history of masturbation, although the
edited book Martha is working on will help rectify that omission.

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