In the 1870s, the noted French naturalist Jean-Henri Fabre noted that male moths were flying for miles around to visit a female moth caged in his lab. {ads) Fabre speculated that the female moth was emitting a chemical scent that was attracting the males. Almost a century later, in 1959, the German chemist Adolf Butenandt ushered in the age of modern pheromone research when he successfully isolated the active chemical, bombykol, that proved so alluring to male moths.

Noted author Lewis Thomas examined the powerful effect of this remarkable chemical messenger on the male moth in his short essay, “A Fear of Pheromones.”

“The messages are urgent, but they may arrive, for all we know, in a fragrance of ambiguity. ‘At home, 4 p.m. today,’ says a female moth, and releases a brief explosion of bombykol, a single molecule of which will rattle the hairs of any male within miles and send him driving upwind in a confusion of ardor.

But it is doubtful if he has an awareness of being caught in an aerosol of chemical attractant. On the contrary, he probably finds suddenly that it has become an excellent day, the weather remarkably bracing, the time appropriate for a bit of exercise of the old wings, a brisk turn upwind. En route, traveling the gradient of bombykol, he notes the presence of other males, heading in the same direction, all in a good mood, inclined to race for the sheer sport of it. Then, when he reaches his destination, it may seem to him the most extraordinary of coincidences, the greatest piece of luck: ‘Bless my soul, what have we here!’ (“A Fear of Pheromones,” Lewis Thomas in The Lives of a Cell, 1974, Bantam Books)

The sixth sense?

Attraction, courtship and reproduction are among the most beautiful, complex and baffling of all human interactions. Why are we attracted to one person, but not another? Do we really fall in love at first sight? And how do we know when the “chemistry” is right? The processes that govern how, why and with whom we fall in love have eluded and frustrated artists, poets, philosophers and scientists through recorded history.

Now, modern research is beginning to shed light on some of the mystery surrounding sexual attraction. Researchers and scientists are now convinced that chemical signals, invisible to our five normal senses, play an important role in not only how we select a mate, but also whether we can bond and remain with that partner over a lifetime. And as it turns out, the long sought path to the human heart may be right under our nose.

Sex sells

Modern advertising employs an almost obscene range of erotic imagery to grab our attention—and for good reason. Millions of years of selective evolution have given modern humans a brain that is hard-wired to respond to visual sexual cues. Consequently, when we search for a prospective mate our initial selection is based on perceived visual attributes such as attractiveness, symmetry, fitness, health and social status. Once a suitable prospect has passed inspection and been allowed to approach to within arms’ length, a new set of biologically produced chemicals begin to exert a subtle yet profound effect on our desire. These chemicals, called pheromones, are sexual messenger molecules produced to convey a subconscious message of sexual interest and intent.

Isolating human pheromones

In the 1960s, a group of anatomists at the University of Utah began to investigate the chemistry of human skin using cells recovered from used arm and leg casts. During the course of their work one of the researchers noticed something unusual—when vials containing these chemicals where left open, the previously contentious and aggressive demeanor of the laboratory researchers began to give way to a cheerful sense of good will and camaraderie. Later, when these same vials were closed, the scientists drifted back to their previous habits of competition and isolation.

Over the next 30 years scientists embarked on a search for this odorless chemical with the power to turn a group of grouchy lab workers into a cooperative and energized team.

Pheromones

The word pheromone comes from the Greek words Pheran (to transfer) and Horman (to excite). Pheromones are complex organic compounds utilized by all animals, from protozoa to the higher primates, as a means of communication. In complex animal societies specialized pheromones facilitate the cooperation of individuals for a number of functions. Some examples:

• Insects such as ants and bees use alarm pheromones to trigger an instant and violent response if a colony comes under attack.
• Rabbits release dispersion pheromones to demarcate territorial zones and to disperse members of the group in the presence of a threat.
• And boll weevils produce aggregation pheromones to inform others of the presence of food or new habitats for colonization.

While specialized pheromones can serve a range of species-specific purposes, sexual pheromones play an identical role in all species—they convey sexual excitement and intent to potential mates.

The vomeronasal organ

Garden variety odors and scents are detected by cells within the nasal cavity by the main olfactory epithelium (MOE). Pheromones, on the other hand, are perceived by a separate accessory structure known as the Vomeronasal organ (VNO). In 1813, the Danish anatomist Ludvig Jacobson described his discovery of this organ located in the nasal cavity of mammals. The VNO has been shown to be exclusively connected to specialized centers of the limbic system.

Once believed to be a purely vestigial organ in humans, research has confirmed the existence of the VNO in humans. In one study in 1958, histological examination of the nasal septum revealed the presence of vomeronasal cavities in approximately 70 percent of all adults. Later, microscopic examination in 1991 was able to clearly identify the presence of vomeronasal organs in 100 percent of adult subjects. This lead to the conclusion that the VNO is present in adult humans, and that this specialized chemosensory organ has evolved to do one thing: detect human sexual pheromones.

The limbic connection

Researchers have shown that the human VNO is connected directly to the limbic system, that part of the brain that is responsible for exploration, flight or fight, for identifying with the environment and reacting to it. The limbic system is also responsible for controlling emotional and behavioral patterns. As William Regelson, M.D., describes it, “You can tell when someone is paying attention or reacting to you with a deep connection, because their eyes glow. This is because they connected with their limbic system. You’re really limbic when you’re in love—your eyes glow. If you’re a religious fanatic, your eyes glow. If someone is in love with you, you can tell, because their eyes glow—they’ve formed a deep limbic connection with you. And this is why the eyes are, in a very real sense, the seat of the soul. And I think that pheromones are really the key limbic stimulants involved in love and lovemaking.”

Timing of menstrual cycles

Once the presence of a working pheromone receptor (VNO) in humans was proven, the next step lay in understanding how pheromones actually work on humans. Unlike insects, humans do not drop everything at the first whiff of a few delicious carbon molecules and assume the mating position. But for all our evolved sophistication and Byzantine sexual cues and responses, an accumulating body of data has firmly established the working presence of these stealthy chemicals.

One of the first indications that humans produce and respond to pheromones was the discovery that women living in close proximity tend to synchronize menstrual cycles within a few short months. Researchers then discovered that chemicals produced in the armpits of females at different phases of the menstrual cycle influence the timing of their cycles. In a 1988 study by Stern and McClintock, researchers collected underarm perspiration from women at specific intervals during their monthly ovulation cycles. After the samples were treated to render them odorless they were applied above the upper lips of a second group of female volunteers. The results were that the onset and length of the ovulation cycles of the second group of volunteers were altered to synchronize with the first group.

Investigators speculate that the synchronization of menstrual cycles is an evolutionary trait with two important purposes: First, by closely timing their menstrual cycles, women would reject all the men of their group at the same time and force them to go out to hunt. Second, by synchronizing the menstrual and birthing cycles, women would give birth at the same time, allowing them to optimize available resources for the care and protection of their young.

“This study, I think, really is the first definitive study that shows that humans have pheromones,” said McClintock at the conclusion of the study. “We still need to know whether we use them on a regular basis, but they are there.”

Page 1 of 2 pages  1 2 >

References

Articles of Interest from Smart Publications Health & Wellness Update

• Human Pheromones: The Science Behind the Scent of Attraction
• Nature’s Most Irresistible Sexual Signal - Human Sexual Pheromones!
• Pheromones Enhance Mood, Self-Esteem, and Social Confidence … Instantly