Jesse Bering - One reason why humans are special and unique: We masturbate. A lot.

Jesse Bering over at Scientific American offers up a revealing look at America's other favorite past time - masturbation. According to the article,

we alone have the power to conjure up at will erotic, orgasm-inducing scenes in our theater-like heads … internal, salacious fantasies completely disconnected from our immediate external realities. One early sex researcher, Wilhelm Stekel, described masturbation fantasies as a kind of trance or altered state of consciousness, “a sort of intoxication or ecstasy, during which the current moment disappears and the forbidden fantasy alone reigns supreme.”

I guess that's why 95% of men admit to masturbation and the other 5% are lying.

One reason why humans are special and unique: We masturbate. A lot.

By Jesse Bering

There must be something in the water here in Lanesboro, Minnesota, because last night I dreamt of an encounter with a very muscular African-American centaur, an orgiastic experience with – gasp – drunken members of the opposite sex and (as if that weren’t enough) then being asked by my hostess to wear a white wedding dress while giving a scientific keynote presentation. “Does it make me look too feminine?” “Not at all,” she assured me, “it’s a man’s dress.”

Now Freud might raise his eyebrows at such a lurid dreamscape, but if these images represent my repressed sexual yearnings, then there’s a side of me that I apparently have yet to discover. But I doubt that this is the case. Dreams with erotic undertones are like most other dreams during REM sleep—runaway trains with a conductor who is helpless to do anything about the surrealistic directions they take. Rather, if you really want to know about a person’s hidden sexual desires, then find out what’s on his or her mind’s eye during the deepest throes of masturbation.

This conjuring ability to create fantasy scenes in our heads that literally bring us to orgasm when conveniently paired with our dextrous appendages is an evolutionary magic trick that I suspect is uniquely human. It requires a cognitive capacity called mental representation (an internal “re-presentation” of a previously experienced image or some other sensory input) that many evolutionary theorists believe is a relatively recent hominid innovation.

When it comes to sex, we put this capacity to very good—or at least, very frequent—use. In a now-classic, pre-Internet-porn (I’ll get to that later on) study by British evolutionary biologists Robin Baker and Mark Bellis, male university students were found to masturbate to ejaculation about every 72 hours, and “on the majority of occasions, their last masturbation is within 48 hours of their next in-pair copulation.” If they’re not having intercourse every day, that is to say, men tend to pleasure themselves to completion no more than two days prior to having actual sex.

Baker and Bellis’s quite logical argument for this seemingly counterintuitive state of affairs (after all, shouldn’t men try to stock up as much sperm as possible in their testes rather than spill their seeds so wastefully in a rather infertile swath of toilet paper or a dirty sock?) is that because there is a “shelf-life” for sperm cells – they remain viable for only 5-7 days after production – and because adult human males manufacture a whopping 3 million sperm per day, masturbation is an evolved strategy for shedding old sperm while making room for new, fitter sperm. It’s quality over quantity. Here are the adaptive logistics.

The advantage to the male could be that the younger sperm are more acceptable to the female and/or are better able to reach a secure position in the female tract. Moreover, once retained in the female tract, younger sperm could be more fertile in the absence of sperm competition [sexually monogamous relationships] and/or more competitive in the presence of sperm competition [in which the woman is having sex with other men]. Finally, if younger sperm live longer in the female tract, any enhanced fertility and competitiveness would also last longer.

Unconvinced? Well, Baker and Bellis are clever empiricists. They also apparently have stomachs of steel. One way that they tested their hypotheses was to ask over 30 brave heterosexual couples to provide them with some rather concrete samples of their sex lives: the vaginal “flowbacks” from their post-coital couplings, in which some portion of the male’s ejaculate is spontaneously rejected by the woman’s body.

The flowback emerges 5-120 min after copulation as a relatively discrete event over a period of 1-2 min in the form of three to eight white globules. With practice, females can recognize the sensation of the beginning of flowback and can collect the material by squatting over a 250 ml glass beaker. [And here comes a useful tip, ladies…] Once the flowback is nearly ready to emerge, it can be hastened by, for example, coughing.

As the authors predicted, the number of sperm in the girlfriends’ flowbacks increased significantly the longer it had been since the boyfriend’s last masturbation -- even after the researchers controlled for the relative volume of seminal fluid emission as a function of time since last ejaculation (the longer it had been, the more ejaculate was present). If only the parents of teenage boys had these findings available for the first hundred thousand years of our history, think of all the anxiety, guilt and shame that might never have been.

In fact, even the father of adolescent psychology research, G. Stanley Hall, had a particularly nasty thorn in his paw when it came to the subject of masturbation. Hall accepted that spontaneous nocturnal emissions (i.e., “wet dreams”) in adolescent boys were “natural,” but he viewed masturbation as a “scourge of the human race … destructive of that perhaps most important thing in the world, the potency of good heredity.” In Hall’s view, the offspring of teenage masturbators would show signs of “persistent infantalism or overripeness.” Boys will be boys, Stanley, and how wrong you were.

Read the whole article.