On June 6, 1969, a detective in southern Michigan, apparently sensing some scholarly significance in the unusual case report before him, sat down at his desk and typed up a matter-of-fact, single page cover letter to an associate at the Kinsey Institute for Sex Research at Indiana University in Bloomington. The detective was writing with regard to a male patient who was being held voluntarily at a Kalamazoo psychiatric ward, a polite, self-confessed “rubberphile” who, in the darkest burrows of his own deep shame and mortification, with the electric summer hum of cicadas, the shrill of rusted gurney wheels and the groans of fellow patients as an orchestra for his thoughts, had for several long weeks before sat hunched over in his bed trying furiously to expurgate his sexual demons through his pen. “ This report is my soul and will save my life ,” wrote the patient. And it’s this report that came to land soon after on the detective’s desk, was looked at askance and stuffed in a manila envelope, borne off by airmail to Bloomington and eventually shelved discreetly with tens of thousands of other such reports in the Kinsey Institute’s unpublished archives.

Forty years later, under the soft glow of fluorescent lighting in the Institute’s library, I happened across this fetishist’s handwritten sexual autobiography—along with the detective’s austere covering note—while working on my new book Perv, and I must say that this man’s presentation of his condition was an articulate, startling self-exorcism. In a document still effervescent with fear and spanning some fifty pages of lucid, densely packed prose peppered with biblical scripture, this tortured forty-one-year-old rubber-lover—who’d been arrested for various rubber-related crimes, the most minor of these being his making thousands of indecent phone calls to department store saleswomen, inquiring about rubber bikinis for his imaginary wife while fondling laminated advertisements of elastic-clad models with one hand and himself in the other—worked feverishly to understand the origins of his own insatiable desire for rubber and flesh. To the best of his knowledge, it all started when, at the age of seven, he’d stumbled upon his mother’s glistening white rubber bathing suit hanging on a clothesline on the back porch, an arousing event that coincided with his first becoming aware of that strange stirring in his loins.

What began as an innocent enough youthful peccadillo, however, would eventually grow horns and become a highly fetishistic—and criminal—adult sexual identity. “He would type on a 3X5 card that he liked to squirt sperm into rubber caps or rubber girdles,” wrote the detective, who in clichéd administrative dishevel left the signature stain of a coffee mug on the police station memo. “Then [he would] place the cards in the victims’ mail box and sometimes under the windshield wiper of their cars.” You may think this pathological rubber-lover is an extreme case of sexuality gone awry, which it may very well be. But in studying the sexually abnormal, researchers can gain unique insight into the nuanced, otherwise hidden mechanisms of standard human sexual development and psychosexuality. The rubberphile’s early childhood exposure to his mother’s bathing suit, an impossibly white piece of material still beaded with lake water and fragrant with her perspiration, was perhaps simply coincident with a happenstance erection. Yet this alchemy was so powerful that once he massaged that elastic between his little thumb and forefinger, all was forever lost.

This basic developmental system, one in which certain salient childhood events “imprint” our psychosexuality, may not be terribly uncommon. In fact, that early childhood experiences mould our adult sexual preferences—specifically, what turns us on and off, however subtle or even unconscious these particular biases may be—could even be run-of-the-mill. And just like the institutionalized rubber-lover, the more carnally humdrum and vanilla among us might also owe our more secret preferences in the bedroom to our becoming aroused, at some point in the distant past, by our own parents, relatives or childhood friends.

Consider the case of a 29-year-old woman reported in an old Archives of General Psychiatry article, who noticed to her dismay that she wasn’t averse to a bit of sadomasochism and penis-gazing when having sex with men. On accounting for these strong erotic triggers, the woman recalled: 


When I was four, my father once caught me masturbating. He put me over his knee and smacked my buttocks. He was in pajamas, and the slit in front of his trousers opened widely, so that I could see his big penis and dark scrotum moving quite near my mouth each time he raised his hand … Ever since, I subconsciously connected the smacking of my buttocks with the view of his penis and my first sexual excitement.
The trouble, of course, is that childhood sexual experiences, and in particular their causal relationship with adult human sexuality, is an elusive topic to study, at least in any rigorously controlled sense. It’s also an area of research that a prudish society—or at least one that views an individual’s sexuality as appearing out-of-the-blue with the first pubescent flush of hormones (or, alternatively, as unfolding in some highly innate, blueprinted sense impenetrable to experience, e.g., “the gay gene”)—prefers to look away from, in spite of its centrality to the human experience. Unlike, say, studying children’s acquisition of language, examining the precise developmental pathways to adult sexuality is more or less impossible. That’s not because it’s empirically impossible but rather only because childhood sexuality is one of those third-rail topics that gets zapped by the electric fencing of university ethics boards and is therefore at risk of always remaining little understood. So as intriguing as retrospective self-reports like the ones above may be, they are, alas, little more than anecdotes.

But never underestimate the cleverness of a good experimentalist. Although examining the precise causal links between early exposure to specific stimuli and later adult sexual preferences is not exactly amenable to experimental manipulation, there may be ways yet to explore some more general developmental mysteries of sexuality using controlled laboratory methods. For example, for many investigative purposes, children are easily enough replaced by rats, and that’s just what Yale University researchers Thomas Fillion and his colleague Elliot Blass did in a now-classic study showing just how important early developmental experiences can be in shaping adult sexuality. As reported in their 1986 study in Science , Fillion and Blass took three female rats that had just given birth to a litter of pups and experimentally altered the mothers’ odors in different ways. One of the rat dams had her teats and vagina coated with a lemony scent called citral; another dam had only her back coated with the same citral scent; and finally the third mother rat went lemonless—instead, her teats and vagina were simply painted with an odorless isotonic saline solution. So, if you’ll follow this through, once the dams were placed back with their suckling babes, the females’ litters of pups differed from one another with respect to the particular odor—or at least the location of the odor—emanating from their mothers while she nursed.

Once they were weaned, the young rats were removed permanently from their mothers and went about doing things that juvenile rats do (such as playing and, apparently, laughing). Then, at about 100 days of age, the sexually mature male rats from these initial litters were introduced, individually, to one of two receptive female rats. Here’s the trick, though. Prior to their introduction to the males, Fillion and Blass had coated one of these females perivaginally with citral scent, and they left the other with her vagina smelling au naturel. Although the citral-scented female genitals made little difference to males from the two other litters—they were happy to have sex with either female—those males that, as pups, had suckled from a mother whose teats and vagina were redolent with lemon ejaculated significantly faster when they were now paired as adults with a lemony female sexual partner. In fact, the investigators reported that these males even had trouble achieving orgasm when mating with the odorless (or at least, odorless as far as rat vaginas go) females.

But can we generalize these Oedipal rat findings to the development of human sexuality? As far as I’m aware, similar studies have not been done with our own species—although it is interesting to speculate on the possible effects of human breastfeeding on the sexual preferences and biases of adult men. (I have oftentimes wondered how many exclusively gay men there are out there who were bottle-fed as infants and whether or not, as one factor among many in such a complex phenomenon, male homosexuality is more frequent in societies in which bottle-feeding is more routinely practiced.) Tethered as we are to the idea that children are asexual, however, it’s unlikely that we’ll ever know for certain whether or not these data have any analogues with human sexuality; and furthermore I’d imagine that it would be a real challenge to find mothers willing to tinker with their child’s development in this shame-ridden domain. Turning one’s son into a fetishist with an unhealthy attraction for reproductive organs that smell like Lemon Pledge may well be going above and beyond the call of scientific duty, even if it is done for admirable humanitarian reasons.

Yet there is at least one recent study that hints at related mechanisms in our species. In a forthcoming report in Personality and Social Psychology Bulletin by University of Illinois at Urbana-Champaign psychologist Chris Fraley and New Mexico State University’s Michael Marks—a study that would make Freud smile in his grave and give a long-fingered salute to his many critics—these investigators show that sexual attraction to one’s own biological parents isn’t as deviant or abnormal a thing as you might assume. In fact, evidence of these hidden desires, say Marks and Fraley, raise important questions for traditional psychological accounts of incest avoidance.

First, a quick primer on incest avoidance theory. Over the past few decades, and in contrast with Freud’s psychoanalytic model, most evolutionarily-minded researchers have argued that human beings possess evolved psychological adaptations designed to avoid incest. Steering clear of biological kin as sexual partners makes good sense in this respect, because having intercourse with someone who shares too much of your own genetic material tends to produce offspring with various abnormalities hindering their reproductive potential, and thus you're compromising your own overall genetic fitness. And, indeed, numerous studies, in both our own species and others, reveal a so-called “Westermarck effect,” the alleged adaptive system named after the late-19 th century Finnish anthropologist, Edward Westermarck, who was the first to use Darwinian logic to account for the culturally universal taboo against sex with close relatives.

Over the years, scientists have worked to refine Westermarck’s basic idea, with many arguing that our species has evolved something of an unconscious kinship calculator to estimate the likely genetic relatedness of others in our environment. If the calculator produces too high a hypothetical figure in its shared genes number-crunching, then disgust and sexual aversion kicks in. For example, being raised in close proximity with another person of similar age means—to your unconscious brain that has evolved to detect such patterns, anyway—that there’s a good chance that he or she is your biological sibling. This is often cited as the main reason that cultures with “minor marriage” practices, where young girls are raised together with their future husbands in preparation for their later matrimony, tend to produce barren households, since these individuals feel little to no sexual desire for one another as adults.

The trouble with adhering too rigidly to such Westermarckian ideas, say Fraley and Marks, is that people very often end up with spouses that resemble themselves along a variety of physical dimensions—a widely observed phenomenon known as homogamy . This seems to be a matter of sexual imprinting rather than a simple preference for others who resemble us. In one study, for instance, adult married women who’d been adopted as young children were asked to bring to the lab a photograph of their adoptive father along with a separate photograph of their husband. Another group of participants, naïve to the purpose of the study, were able to match which husband went with which adoptive father at a level better than chance.

Homogamy doesn’t apply to every couple, of course, and in fact my own partner is Mexican and, fortunately for him, couldn’t look less like me—or my father, for that matter. My brother and his wife, however, could easily be mistaken for fraternal twins, and their children are perfect miniatures of the Bering-esque gestalt. Empirically, there’s no accounting yet for such individual differences in same/different erotic preferences (although, ahem, my own taste for Latinos may be due to my spending many formative years in South Florida).

While there are always exceptions to the rule, Fraley and Marks have produced a set of startling findings that have temporarily hobbled conventional Westermarckian notions . First, when college students were asked to judge photos of strangers on a scale of sexual attractiveness, the faces in the photos were seen as being significantly more appealing when they were preceded by photos of the student’s own opposite-sex parent via subliminal primes (rather than the face of another student’s opposite-sex parent). That is to say, the participants were more aroused by strangers when the image of their mother’s face (for males) or their father’s face (for females) were still burning unconsciously in their mind’s eye.

On a similar task in which participants were again asked to rate the sexual attractiveness of strangers, individuals got more hot-and-bothered by faces that were morphed with their own faces than they did for faces that were morphed with an unrelated face. In fact, the more that the participant’s face was morphed with that of the target, the more sexually attractive the participant felt the target was. Since we share 100% of genes with ourselves—a sort of experimentally created identical twin, in this case—such findings raise some intriguing new problems for traditional kinship calculator models of incest avoidance, which are often said to factor in salient physical cues reflecting likely genetic relatedness. But interestingly enough, when participants were explicitly informed that their faces had been morphed with that of the target image, this led to “diminished feelings of desire” for their own hybridized face. When individuals were made consciously aware what exactly it was that they were getting aroused by, the “incestuous” effect flat-lined. As the authors point out, it was only once Oedipus Rex—the most famously literal mother-f’er of all time—discovered that he was sleeping with his mother that he gauged out his own eyes.

Based on these findings, Fraley and Marks conclude that, although cultural taboos against incest continue to serve an important adaptive function in preventing our having sex with people that are too closely related to us,



the so-called Westermarck effect is not a result of innate mechanisms that inhibit desire for individuals with whom one was raised but is instead a result of [cultural] habituation … beneath the surface, those early experiences are setting the stage for a set of preferences that essentially co-opt early attachment and caregiving experiences in the service of sexuality, leading people to find attractive in others features that are shared by their family members.
If only that long-forgotten rubberphile knew of such curious mechanisms of sexual imprinting in humans and other animals, he may have found some solace in science rather than being relentlessly hounded by feelings of religious guilt. What an unfortunate thing to be the same in underlying principle but, owing to something largely out of one’s control, so different in technical expression.

Actually, perhaps it’s not too late for him after all. In his 1969 cover letter, the detective wrote that our rubber-lover was presently in the psychiatric ward, “ where he hopes to spend the rest of his life and he wishes to live to be a real old man.” According to my calculations, the fetishist would be eighty-two years of age today. If the Kalamazoo hospital staff was ever computer savvy and liberally-minded enough to permit their inpatients to browse online, I do hope he lived long enough to experience the sexual Renaissance of the Internet…he’d have found tens of thousands of others like him who would have happily indulged his fantasies without his resorting to criminal activity.

And maybe, just maybe, he’s reading this article right now, thinking fondly of his mother clad in white rubber.



In this column presented by Scientific American Mind magazine, research psychologist Jesse Bering of Queen's University Belfast ponders some of the more obscure aspects of everyday human behavior. Sign up for the RSS feed, visit www.JesseBering.com, friend Dr. Bering on Facebook or follow @JesseBering on Twitter and never miss an installment again. For articles published prior to September 29, 2009, click here: older Bering in Mind columns. Jesse's first book, The Belief Instinct (Norton) [The God Instinct (Nicholas Brealey) in the U.K.], will be published early February, 2011.

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