***
One reason why humans are special and unique: We masturbate. A lot
"This conjuring ability to create fantasy scenes in our heads that literally bring us to orgasm when conveniently paired with our dexterous 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...
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”...
Baker and Bellis’s quite logical argument for this seemingly counterintuitive state of affairs... 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...
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...
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)...
We are the only primate species that seems to have taken these seminal shedding benefits into its own lascivious hands... As anybody who has ever been to the zoo knows, there's no question that other primates play with their genitalia; the point is that these diddling episodes so seldom lead to an intentional orgasm...
Several groups of wild gray-cheeked mangabeys were observed for over 22 months in the Kibale Forest of Western Uganda. There was plenty of sex... but just two incidents of male masturbation leading to ejaculation were observed. Yes, that’s right. Whereas healthy human males can’t seem to go without masturbating for longer than 72 hours, two measly cases of masturbating mangabeys were observed over a nearly two-year period...
E.D. Starin didn’t have much luck spying incidents of masturbation in red colobus monkeys in Gambia, either... a 5.5-year period of accumulated observations totalling more than 9,500 hours, she saw only 5–count ‘em, five –incidents of her population of five male colobus monkeys masturbating to ejaculation, and these rare incidents occurred only when nearby sexually receptive females were exhibiting loud courtship displays and copulations with other males... What did the monkeys do with the “product”? Well, they ate their own ejaculate—and in one case, a curious infant licked it off the adult’s fingers...
Earlier in the article [Hamilton] reports that one of his female monkeys named “Maud” liked to be mounted (and entered) by a pet male dog out in the yard until one day poor, horny old Maud offered her backside to a strange mongrel that proceeded to bite off her arm. More disturbing is Hamilton’s description of a monkey named “Jimmy” who one sunny afternoon discovered a human infant lying in a hammock: “Jimmy promptly endeavoured to copulate with the infant,” observes Hamilton matter-of-factly. It’s unclear whether or not this was the author’s own child...
So why don’t monkeys and apes masturbate even nearly as much as humans? It’s a rarity even among low status male nonhuman primates that frustratingly lack sexual access to females–in fact, the few observed incidents seem to be with dominant males... The answer for this cross-species difference, I’m convinced, lies in our uniquely evolved mental representational abilities—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...
Frequency of erotic fantasies correlates positively with intelligence... Lukianowicz argues that erotic fantasies involve imaginary companions not altogether unlike children’s make-believe friends. But unlike the more long-lived latter, he concedes, the former is conjured up for one very practical purpose: “… as soon as the orgasm is achieved the role of the imaginary sexual partner is completed, and he is quite simply and quickly dismissed from his master’s mind”...
In one study with 141 married women, the most frequently reported fantasies included “being overpowered or forced to surrender,” and “pretending I am doing something wicked or forbidden.” Another study with 3,030 women revealed that “sex with a celebrity ,” “seducing a younger man or boy,” and “sex with an older man” were some of the more common themes... According to one study, the top five lesbian fantasies are “forced sexual encounter,” “idyllic encounter with established partner,” “sexual encounters with men,” “recall of past gratifying sexual encounters,” and—ouch!—“sadistic imagery directed toward genitals of both men and women.”
One of the more intriguing things that Leitenberg and Henning conclude is that, contrary to common (and Freudian) belief, sexual fantasies are not simply the result of unsatisfied wishes or erotic deprivation:
Those with the most active sex lives seem to have the most sexual fantasies, and not vice versa. Several studies have shown that frequency of fantasy is positively correlated with masturbation frequency, intercourse frequency, number of lifetime sexual partners, and self-rated sex drive.
... Leitenberg and Henning’s piece was written over fifteen years ago, summarizing even older research. The reason this is important is because it was still long before the “mainstreaming” of today’s Internet pornography scene, where zero is left to the imagination."
