Hirsch says scientific knowledge of the human smell and taste (olfactory and gustatory) senses is 150 years behind other sensory knowledge. Comparing it to opthalmology, he says it is as if science is just now getting around to creating the equivalent of eye-examination charts for smell and taste.
SMELL AND TASTE HAVE usually been classified as the ”lower” of the five basic senses because they are less informative and consist of relatively simpler physiological structures than say the eye and ear. Conventional wisdom holds that taste and smell may once have played a more key role in determining human behavior but that man`s evolution into a civilized being reduced that role. Hirsch, through his own and others` research, is not entirely swayed by the conventional wisdom.
”Odor is the quickest way to induce human memory and emotion,” he says. That is so, he says, because odors travel directly through the nose to the most primitive parts of the brain, the limbic system and the hypothalamus, which give our impulses to emotion, hunger and reproductive cycling.
”A specific odor, say of a certain flower or food, can trigger instantaneous memories of our childhood, flooding us with the mood of a moment long ago,” Hirsch says. ”We call this olfactory-evoked recall. It can be pleasant or unpleasant. The smell of gunpowder is the fastest means of flashback for war veterans suffering with post-traumatic stress disorder.”
Most animals and insects rely more heavily on their sense of smell in regulating their behavior. They use it to identify individuals, as an alarm signal for impending danger and to search for and identify food. Smell is vital to animal reproduction. Females in all mammal species produce a scented pheromone to signal male members of their species that they are in heat.
THE ORGANS AND BRAIN centers in animals that trigger olfactory responses in their behaviors are present in humans, too, though humans do not seem to respond to them so manifestly as other animals. We know, for example, that human babies identify their mothers initially, in part, by smell, though this rudimentary behavior seems to drop off with age.
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Sigmund Freud suggested that human evolution toward civilization was accompanied with a stunting of human abilities to smell. This stunting, he said, may account for the development of various human neuroses, particularly with things sexual.
”It (the stunting of the sense of smell) would thus furnish an explanation for the fact, that with the advance of civilization it is precisely the sexual life which must become the victim of repression,” Freud wrote in 1908.
But Hirsch points out that what triggers a sexual response in other mammals is present in humans, too. Humans have apocrine glands under the arms and around their genital areas, the same glands that other animals use to produce pheromones, a sexual scent. And humans, too, have an area in the brain called the vomeronasal organ that, in animals, responds to the pheromone scent and results in sexual arousal.
Humans, too, produce pheromones, though they have never been isolated and identified (despite perfume companies throughout the world working madly to do so). Because we produce pheromones, Hirsch believes they have an intrinsic role still in dictating some part of our sexual behavior, though the evidence is somewhat circumstantial.
During sexual arousal, he points out, membranes in our nasal passages become engorged and our sense of smell increases. Women, who generally have a better sense of smell than men, anyway, are even more sensitive to smells at the time of ovulation. Hirsch also believes the presence of human pheromones eventually will explain the so-called ”college roommate effect.” That is a fairly common phenomenon in all-women dormitories in which, after a period of a few months, the menstrual cycles of the women living in the dorm become synchronized, all occurring at the same time.
”It`s all very subliminal,” Hirsch says, ”but I would go so far as to say eventually we will talk not about `love at first sight,` but about `love at first sniff.` I think an enormous part of first impressions that we form when we meet people are made subliminally by olfactory sensations.”
Hirsch believes our sense of smell (or lack of it) may provide us with important clues to human behavior, both mental and physical. His own research began, for example, with his discovery that certain mental debilities, such as Alzheimer`s and Parkinson`s disease, are accompanied by a loss of smell sensitivity. From clinical observation, he says he believes the onset of many diseases are accompanied by the inability of the patient to detect certain specific odors. If these odors can be linked universally with specific diseases, he says medicine will be able to use the odors as ”markers” or diagnostic tools.
He also sees the possibility of medicine eventually taking advantage of
”olfactory-evoked recall” as a psychiatric tool. Specific odors, he says, could be used to induce patients to search into their pasts in a way some analysts now use hypnosis.
As we learn more about our noses, Hirsch says we will see a vast array of new commercial applications of odors and odorants. The Japanese, he says, not surprisingly, already are ahead of the Americans in this area. A Japanese clock manufacturer, for example, already is marketing an alarm clock that, instead of ringing a bell, wakes up its user by scenting the room with a fragrance that is designed to stimulate alertness. Similarly, Japanese offices are experimenting with office fragrances that induce alertness.
Indeed, Hirsch sees a certain danger in unleashing scent-sophistication on an unwary buying public. Some used-car dealers, for example, spray a commercially available ”new car” smell when they put their wares up for sale. Some realtors, too, have been known to spray a fresh-baked bread scent in the kitchens of homes before showing them to prospective buyers.
”The real danger,” Hirsch says, ”is if somebody develops a subliminal scent that induces a mood conducive to shopping that could be used in shopping malls and stores. These people already are using well-researched lighting and coloring schemes that are designed to do just that. Somehow, I just don`t think that would be fair.”
HIRSCH BELIEVES THE research his and other taste and smell laboratories are conducting will provide significant payoffs for medicine and for consumers within the next 10 years. He predicts a growing interest in such research because of the aging population in the U.S.
”Age plays a significant factor in the loss of taste and smell sensitivity,” he says. ”We lose our ability to smell on a very predictable curve. More than 50 per cent of people between 65 and 80 years of age have a major loss of olfactory sensitivity. That rises to 75 per cent for people 80 years or older. That is why so many elderly women use too much perfume. They put on a normal amount and they can`t smell it, so they just keep applying it until they can, never realizing that what they are doing is overwhelming to those with a normal sense of smell.”
Hirsch has developed some intriguing theories about aging and the loss of taste and smell sensitivity.
”One thing for sure,” he says, ”I don`t think younger people should be cooking for older people. A 20-year-old is far more sensitive to the taste of food than a 70-year-old. What tastes fine to a younger cook in a nursing home usually is bland or totally without taste to elderly diners. They end up not eating enough or loading up their food with salt, which is bad for them. Older people should be cooking for older people.”
The marketplace, Hirsch says, is missing a good bet in catering to older people whose taste sensations have diminished. Tens of thousands of artificial flavors, called odorants, already exist in the market. Hirsch says these could be used to strengthen the natural flavors of foods, thus restoring much of the enjoyment of eating lost to elderly diners.
”To you or me, these strengthened flavors might be overwhelming. For somebody who hasn`t really tasted their food for years, it would be wonderful. It`s something that should be done, and it would help people. If I were a businessman, I`d be marketing a line of frozen foods right now aimed at the elderly market. I`d call them `elderly edibles` or something. With the aging population we have right now, somebody is going to make millions. Mark my words.”