There are several interesting clues regarding how male visual interests form. First, many male sexual obsessions appear to form after a single exposure, rather than after repeated pairings of a neutral stimulus and an arousing stimulus. Second, almost all lifelong sexual interests in men first form during adolescence. Clinicians report that it is very rare for an adult man to form a new sexual obsession with a visual object. If the male desire software was operating solely according to the principles of conditioning, then age should not be a significant factor. Instead, there appears to be a special window of time when visual sexual interests can form—what neuroscientists call a
critical period
.
In studies where male sheep were raised by goats, the young sheep sexually imprinted upon goats during the sheep’s critical period. Afterward, the male sheep would only try to mate with goats. Other sheep were not sexually desirable. In contrast, when female sheep were raised by goats, their imprinting was reversible. The female sheep could become willing to mate with other sheep. This same pattern of irreversible male sexual imprinting and weak female imprinting was observed when young goats were raised by sheep.
A critical period for sexual imprinting is also supported by research on zebra finches. A male finch’s ideas about what a sexy partner looks like are strongly influenced by how its mother looks. However, this influence only operates during a few months when the bird is about a year old. During this critical period, a visual representation of the ideal female is burned into the male finch brain and will guide its sexual behavior for life. (Intriguingly, female finches are more likely than males to form “visual fetishes,” such as preferring a single brightly colored feather, if their father possessed such a cue. But, unlike humans, the male finch is more colorful and ornamented than the female.) When researchers prevented a male finch from seeing its mother during the critical period, it never developed a visual attraction to female finches.
A male finch’s sexual interest in mother-like visual qualities is an example of what we might call a
cued interest
. A cued interest develops when the brain’s natural responsiveness to a particular kind of cue causes the brain to sexually imprint upon a target that exhibits that cue. An innate visual cue guides the male zebra finch to imprint upon the physical appearance of its mother, creating a cued interest in mother-like finches. In Chapter 1, David Reimer developed a cued interest in girls, even though Dr. Money attempted to condition him to like boys. Breasts, butts, and feet are most likely cued interests.
If men’s brains instinctively target visual foot cues, then a sexual interest in stockings or stiletto heels would also be a cued interest, since they both “match” the male brain’s innate sensitivity to foot cues. Though men are not instinctively responsive to female footwear, the male desire software guiding a man to look at a woman’s feet may lead him to imprint on a cute pair of open-toed Jimmy Choos.
During adolescence and early adulthood, perhaps the male desire software targets specific parts of female anatomy. “I can actually recall when my appreciation for breasts first started,” confesses one forty-two-year-old accountant. “I was fourteen and watching the soft-core video
Taking It Off
. It was the first time I ever saw naked breasts. It was also the first time I ever got an erection. The star of the movie was this actress with a huge chest, Kitten Natividad. Before that, breasts were like elbows or anything else. But watching those huge jugs, it was like putting on an enchanted necklace. I was bewitched.”
Cued interests don’t always have a distinct moment when they form. Many men report that their interest in a particular body part developed over several years without a defining moment, though almost always forming during adolescence or their early twenties. Often, men characterize their cued interests as inexplicable. “I don’t know why I like breasts,” offers comedian Mitch Fatel. “They just sit there and make me happy.” This may be because a cue is unconsciously steering a man’s attention to a particular target. Things are different with
uncued interests.
Uncued sexual interests almost always seem to have a distinct, memorable beginning—an “origin story.”
“When I was nineteen, I had a hydrocele, which is the accumulation of fluid around the testicle. The doctor needed to check how it was doing using ultrasound. So I was in the doctor’s office lying on the cot with my pants down, and the female technician rubbed this warm gel on my testicles. That got my attention, certainly,” explains Billy Chou, a forty-three-year-old Massachusetts government employee. “But then she took the ultrasound tool and began to roll it around my testicles. Instant hard-on. Like a block of iron. Ever since then, I get intensely turned on by doctor’s offices. The moment I get on the crinkly paper of the cot, I get stiff. I love to role-play doctor and patient with my wife. I’m not gay, but once I’m on the exam table I even get hard around a male doctor.”
Uncued interests are rarer than cued interests. The top fifty most popular sexual search categories on Dogpile are all cued interests, according to our reasoning. By definition, uncued interests are much more variable than cued interests, since just about anything can become an uncued interest if it presents itself in the right circumstances.
In our opinion, an uncued interest forms when an unexpected event interferes with the natural sexual imprinting process. Often, uncued interests involve the senses of touch or smell, like the doctor pressing the ultrasound paddle into Billy Chou’s testicles. There may be another factor that strongly influences the formation of uncued interests in men: ejaculation. Most male turkeys initiate sexual behavior the first time they encounter an artificial female turkey, but fewer than half initiate sexual behavior a second time. Which males
do
repeat their amorous attention? Only those who ejaculated the first time.
Unfortunately, there is no research on the formation of uncued interests in humans. It’s difficult to imagine any ethics review board would approve an experiment that required adolescent men to masturbate while probing their testicles with paddles in the hope of instilling a permanent erotic fixation. However, one case from the medical literature supports the importance of ejaculation in forming an uncued interest.
Chaminda was a young Buddhist Sri Lankan living in a town outside of the capital of Colombo. His father was an engineer and his mother died from cancer when Chaminda was very young. As a child, he gathered up brown ants from his garden and kept them in a cupboard in his bedroom, where he fed and took care of them. He called them his “little zoo.” One of his favorite activities was to lie down naked on the floor and let the little ants crawl on his legs, giving him a pleasant tingly sensation.
When he was fourteen, he locked the door to his room and was playing with his little zoo. He tried a new solo activity common to boys around the world: masturbation—or what Sri Lankans call
athe gahanawa
. As he ejaculated, the ants tickled his thighs and testicles. A lifelong interest was forged. Several times a week for the next decade, he would let various insects and creatures crawl upon his naked body while he masturbated furiously, sometimes four or five times in an hour. Sexologists dubbed his erotic passion
formicophilia
—a love of crawling things.
Chaminda’s formicophilia is a perfect example of an uncued interest. Innate cues did not guide the young Buddhist to find ants sexually appealing. Rather, he experienced a special tactile event during his sexual critical period, accompanied by ejaculation. Most of the time, a young man’s brain could expect that the source of a tactile sensation on the penis producing ejaculation was a woman—an appropriate target to imprint upon. But fortune provided Chaminda and Billy Chou—and millions of other men—with a different experience.
Though Chaminda’s formicophilia and Billy Chou’s medical fetish suggest that male sexual imprinting may be flexible, the relative popularity of the various categories of online erotica reveals that uncued interests are quite rare compared to the overwhelming prevalence of cued interests in breasts, butts, feet, penises, and vaginas.
But why are men predisposed toward these body parts in the first place?
THE SEXY FAT
Breasts, hips, butts. Biologists have a name for the oversized parts of female anatomy that men find so enchanting:
ornamentation
. You might think that ornamentation is appealing because it signals a woman’s current fertility. But according to many scientists, that’s not quite right. Instead, the shapely curves of female ornamentation indicate how many years of healthy childbearing remain across a woman’s entire lifetime. The difference between current fertility and future fertility is crucial: current fertility offers a man benefits from a short-term sexual encounter, while future fertility offers benefits from a long-term relationship, such as marriage.
Donald Symons was the first scientist to fully develop the idea that men should find visual cues associated with
youth
to be most attractive. “A nubile woman [i.e., one who is just beginning ovulation and has never been pregnant] would not have been investing her time and energy in other men’s children, would have had more living relatives to invest in her and her children, and would have been more likely to survive until a newly conceived child was old enough to survive on its own,” explains Symons. His ideas are well supported by the Internet, where searches for adolescent women are the most common sexual search around the world by a large margin.
If Symons is correct and the male desire software is designed to prefer adolescent ornamentation over adult ornamentation, this would suggest that men evolved to generally prefer long-term child-rearing relationships over short-term sexual liaisons. If male desire software was designed to prefer one-night stands, men should prefer sex with adult women over adolescents, since adolescents have relatively low fertility. (Most women don’t attain regular ovulation until many years after menarche; over the past century, the age of first menstruation is happening earlier and the onset of regular ovulation is happening later.) Indeed, in most primate species, including chimpanzees, males
do
prefer fertility cues over youth cues. Male chimps do not find adolescents sexually attractive. They prefer mature females. Revealingly, chimpanzees do not form long-term relationships, but instead engage in frequent short-term liaisons.
Though men exhibit a general preference for youth and long-term relationships, the male brain is designed to flexibly pursue both long-term and short-term relationships—what psychologist David Buss calls
mixed mating strategies
. This might be one of the main reasons for the appeal of MILFs. As we saw in the previous chapter, most fans of MILFs emphasize older women’s wishes to avoid romantic complications. MILF fans fantasize about getting seduced by a MILF for a one-night stand rather than wooing her as a girlfriend.
The red rump of the baboon, the orange throat patch of the striped plateau lizard, and the dangly combs of hens are all examples of female ornamentation. But throughout the animal kingdom, male ornamentation, such as the lion’s mane and the peacock’s tail, is far more common. Female ornamentation is found in species where females vary in quality and a female can obtain nongenetic benefits from males, such as food, shelter, or the protection of her offspring. Females compete with other females for these male-provided resources, with the most attractively ornamented females usually obtaining the most benefits. Dozens of young women flaunted their bodies on the adult image site Lightspeed, but the most attractive ones received jewelry, electronics, and cash from male admirers.
Ornamentation evolved as a result of this female competition—through an endless series of beauty pageants where the judges were the most desirable men. As men became more interested in female body parts, women developed bigger and better parts. The women with the best parts attracted the men with brains that targeted these parts. These couples then passed on genes for better parts to their daughters and genes for desiring these parts to their sons.
Across species, more attractive female ornamentation is associated with greater health, fertility, and offspring survival. This is definitely true with regard to human ornamentation. The anatomy that men find attractive—breasts, hips, butts, feet, as well as feminine facial features—are all influenced by the same molecule:
estrogen
. Estrogen is sensitive to a woman’s energy and health. Unhealthy and underfed women produce less estrogen and therefore may not be able to bear children, or may bear unhealthy children. A woman’s estrogen level indicates if she is getting enough to eat, if she’s infested with parasites, and how much stress she’s experiencing. The same way that our taste for sweetness guides us to sugar, which in turn provides us with energy, male visual cues guide men to estrogen, which in turn provides men with improved chances of healthy offspring.
Female ornamentation consists of a specific kind of female-only fat called
gynoid
fat. Gynoid fat supports the energy demands of pregnancy and lactation. Like men, women also possess
android
fat. Gynoid fat is only used during childbearing, whereas android fat is used for everyday energy needs. Android fat accumulates in the trunk and abdomen, and internally. Gynoid fat is stored in the breasts, hips, butt, and thighs.
A woman’s body accumulates its maximum percentage of gynoid fat during adolescence. This accounts for teenage girls’ shapely bodies. Since these estrogen-fueled, gynoid fat–based ornaments are the best indicators of a woman’s long-term reproductive value, youthful forms of these ornaments evolved to become the most potent visual cues for men. There is even evidence that estrogen limits the growth of foot bones. Thus, small foot size might be another indirect indicator of a woman’s health and long-term childbearing prospects.