The sight of a ravishing lady can set your pulse galloping. So can an erotic caress, or a passionate song. But every message from your eyes, skin or ears is communicated to your libido secondhand, after it’s been translated in the brain and linked with past memories.
Not so with the erotic fragrances your nose picks up. Odors go straight to the emotional core of your brain. There, automatic reflex switchboards turn simple chemical messages from the nose into powerfully seductive, primitive emotional reactions long before you realize what’s going on.
Mother Nature has been sharpening our reactions to the “chemistry of love” for millions of years. We humans aren’t as sensitive to odors and their ability to arouse our copulative drive as other animals. But odors still generate electrical impulses that travel straight from the nose to the brain and back in split seconds to set the pulse racing, rivet you to an irresistible target and harden your cock with anticipation.
All it takes for a male moth to find a female looking to mate is a couple of aromatic molecules floating downwind in the night air. He can zero in on his waiting target even if she is a mile away, when she releases her perfumed invitation.
Our sense of smell is more complicated, but we do share some things with other species, including insects, when it comes to scent, sexual behavior and mating. Twenty years ago, Martha McClintock reported one similarity when she found that certain aromatic secretions, known as pheromones, synchronize the menstrual cycles of women living together in college dormitories. This also occurs with women in the office workplace, and with mothers and daughters living together.
We’ve known for years that women are far more sensitive to odors than men, and that women and men produce different pheromones. That’s because different hormone levels control how many apocrine or odor producing glands we have and what kind of pheromones they produce. When bacteria act on perspiration and apocrine gland secretions, the result is a combination of pheromones that affect our sexual behavior.
Women have many more of these tiny apocrine glands than men for generating pheromone production. They are concentrated with sweat glands in the armpits, around the genitals, on the chest and on or around the face places where most of our body hair grows. Hair is important because it traps and holds the seductive pheromone fragrances.
No two people produce the same combination of pheromones. Differences in pheromone production and distribution depend on gender, body temperature, eye color and the amount of chest, facial and body hair. Even the color, type and length of hair may be important. Natural blondes, redheads and brunettes, for example, each produce different pheromones. And, as you might guess, longer or thicker hair traps more pheromones.
The link between odors and sexual behavior is a two way street. When sensory cells in the nose pick up pheromones from another person, signals to the brain control a whole range of sex related hormones produced by our bodies. In turn, hormone fluctuations control the pheromones we produce to influence or attract others.
To understand this provocative phenomenon, we found Jim Kohl, a clinical laboratory scientist, quite a fascinating resource. After focusing the past six years on a search for answers, he has carefully documented a strong biological link between sex and our sense of smell, and how it evolved over the ages to help males and females get together and keep the species thriving.
We asked him about those arousing connections between sex and the nose that Forum readers might find interesting.
FORUM: So how does it all fit together then pheromones and sexual response with hormones like testosterone?
KOHL: Men naturally have more testosterone than women, and testosterone is the main trigger for sex drive. More important, men’s testosterone levels rise faster in response to women’s pheromones than a woman’s testosterone level does in response to a man’s pheromones. I think that’s one factor that explains why men are ready for sex almost any time a woman indicates interest, while women require foreplay to become aroused and enjoy experiencing intercourse.
FORUM: Speaking of enjoyment, do pheromones have something to do with why women sometimes have orgasms even multiple orgasms with one man and none when they’re with a different partner?
KOHL: I’m sure a big part of the answer is that each woman reacts differently to the combination of pheromones a particular man produces. If the combination the “chemistry” clicks, circuits in the woman’s brain will increase the output of the hormone associated with orgasm.
FORUM: Kissing is certainly a popular prelude to sex in many cultures, and you can’t kiss someone without bringing your nose very close to the partner. Do we perhaps kiss because we’re turned on or want to be turned on even more by our partner’s pehromones?
KOHL: That’s part of the answer. Pheromones do get distributed in saliva and are carried on one’s breath. But don’t forget that the lips themselves are also very sensitive and erogenous. Sensations of touch, and even taste, also come into play.
FORUM: And what we see, of course.
KOHL: Sure, but how many of us realize that odors even those we’re not aware of help us figure out what we like or don’t like to see. Odor memories are deeply rooted in the emotional centers of the brain. From birth on, they influence the way we feel about what we see.
FORUM: Is there a connection between pheromones and the bonding between a woman and her nursing child? How does that work?
KOHL: Research shows that a few days after birth, an infant can recognize its mother’s breast odor, and the infant clearly prefers mom’s odor to any substitute. Mothers can also recognize their infants by odor alone within a few hours of birth. Mother child bonding may also be enhanced by hormones that give a woman pleasure when she’s breast feeding. Sucking on the breast releases oxytocin in the brain, and that hormone is known as “the cuddling hormone.”
FORUM: Desmond Morris, author of The Naked Ape, claimed the evolution of the female breast has played an important role in human sexual selection. Is this because the area around the nipple contains pheromone producing apocrine glands, just like the labia around the vagina and the rim of the penile glans?
KOHL: The entire female breast is actually a modified apocrine gland. Evidence from evolutionists and anthropologists leads me to believe that apocrine glands migrated to the chest region and enlarged when humans adopted an upright stance and began walking on two legs instead of four. It makes sense that at about the same time, as women became more “naked” of hair than men, larger breasts compensated for the loss of women’s scent trapping hair. Women’s larger breasts provided a new, improved area for pheromone production and distribution.
FORUM: Your answer suggests another question about breasts. Doesn’t it give us a clue about why American etiquette dictates that women cover their breasts? And what about shaving underarm hair or sitting with the legs crossed?
KOHL: Even though they didn’t know anything about pheromones, many anti sex cultures, including Puritan America, unconsciously developed customs that reduce the ability of sex pheromones to get into the air where they can tantalize and turn men on. You could also add that covering the head or wearing a veil over the face also reduces the spread of pheromones.
FORUM: We’ve heard some heated discussion about your suggestion of a connection between the nose and the worldwide popularity of dancing as a courtship ritual. Why do you think that pheromones contribute to the universality of dancing as a sex ritual?
KOHL: First, body heat stimulates pheromone production, and dancing can certainly turn up the heat. Furthermore, close dancing increases our ability to detect the subliminal turn ons of our partner’s pheromones. Then, there’s an evolutionary trend that makes the average man six inches taller than the average woman. When they’re dancing close, she comes into close contact with the pheromones trapped by his chest, face and underarms. On his side, there are the pheromones in the hair on her head, and her breasts especially if she’s wearing a sexy, low cut dress. Sexy smells make for sexy dancing, and sexy dancing makes for sexy courtships. On the other hand, if either of you doesn’t enjoy that first dance because of an unpleasant odor, the flirtation and courtship may end quickly.
FORUM: do we know any ways that sex smells help us continue bonding after courtship, too?
KOHL: The “honeymoon” may be over when we become accustomed to the same pheromones over a period of time. As we adapt to a partner’s pheromones, the excitement they once provided fades. Of course, if scents were everything, we might never have any lasting relationships. Thankfully, our ancestors didn’t continue to rely so much on the sense of smell for sexual attraction as other animals do. Once we got up off all fours, other systems took over. For example, oxytocin, “the cuddling hormone,” and other natural opiates help us bond and comfort each other after the amphetamine like rush of “falling in love” begins to fade.
FORUM: Since pheromones are concentrated in the pubic area, do they have anything to do with oral sex and its growing popularity in recent years?
KOHL: I’m convinced pheromones are involved in most aspects of human sexual behavior. Take, for example, our emphasis on personal hygiene, deodorants, frequent bathing and hair shampoos. Each of these reduces the amount of pheromones our body hair traps. Still, pubic hair manages to trap a lot of pheromones, and they turn us on what do you think? Aren’t we unconsciously aroused and attracted by the high pheromone concentration “down there,” especially after we wash all the other pheromones down the drain or neutralize them each morning with deodorants?
FORUM: Taking that unconscious attraction a step further, some women like to sleep on “his” side of the bed or wear his robe or shirt when he’s absent. Is this perhaps linked with male scents?
KOHL: It seems likely that it is pheromones trapped in the bed linens or clothing that subliminally attract a woman to her lover’s essence. Maybe his scent is the next best thing to having him there.
FORUM: Do you think this same sort of reaction might explain why children often enjoy sleeping with a security blanket or a favorite teddy bear?
KOHL: Of course. It’s those pheromones that produce a sense of security in the brain. Washing a “blankie” or teddy bear removes the scent and destroys the security message.
FORUM: Does what we know about smell and sexual behavior tell us anything about why a woman’s sex drive is frequently the strongest at mid cycle, when she ovulates and is most fertile?
KOHL: Logically, natural selection favors women who want sex most when they’re most fertile they, in theory, produce more offspring. Several studies show that a woman’s sense of smell is many times more sensitive to a specific musky, male scent, and her testosterone level peaks when she’s most fertile. This all promotes survival of the species.
FORUM: That’s fascinating and sexy all at once. Let me ask you one last question. Does the smell and sex connection teach us anything about why so many women find the sports “jock” more attractive than other males?
KOHL: I do think something can be said for the role of pheromones and the nose in the apparent “sexiness” of athletes. It’s well documented that exercise stimulates testosterone production, and we know that testosterone production increases pheromone production. The connection then is obvious. For many years, behavioral scientists have ignored the role smell plays in human sex. Our olfactory lobes are so small, it was thought they couldn’t possibly be important in sex. Besides, scientists didn’t want to admit that much of what attracts human males and females might be controlled by something as primitive as sexy odors floating through the air.
But why not? You know we humans can discriminate between the odors of mice whose only difference is in a single gene, and pheromones can synchronize menstrual cycles. Why then can’t sexy odors be much more powerful than we think in controlling our hormone levels and our sex drive?
One leading sexologist recently asked why patients with Kallmann’s syndrome, who can’t smell anything, just can’t fall in love. I wonder if it’s because they can’t detect the sexy scent signals of love, infatuation, lust and sex. We agree with Jim Kohl that in the next few years we’re going to see some major breakthroughs and electrifying discoveries about erotic odors and our sexual response.
Dr. Robert T. Francoeur is a professor of human sexuality and embryology at Fairleigh Dickinson University. He is the author of numerous books including Becoming a Sexual Person and also BioMedical Ehtics: A Guide to Decision Making.