The Scent of Desire
Discovering Our Enigmatic Sense of Smell
by Rachel Herz
Morrow, 288 pp., $24.95
In The Scent of Desire, psychologist Rachel Herz, a professor at Brown, wants to elevate our sense of smell--neglected, and even disdained as a part of our animalistic past--to the status of its more essential cousins, sight and sound. She points out that the sense of smell is the primary sense by which much of the animal kingdom negotiates the world. It tells who is family, what is edible, announces fertility, and indicates social hierarchy. Herz acknowledges that vision has become the primary survival sense for humans. But her personal theory is that humans' primordial sense of smell has evolved into our emotional system.
She writes, "I have often wondered whether we would have emotions if we did not have a sense of smell; I smell therefore I feel?"
My personal theory, based on developing hyper-smelling abilities during pregnancy, and living with a beagle for the past five years (a breed of dog Dave Barry describes as "a nose with feet") is that thank goodness our sense of smell is only a vestige of that of other mammals. Oddly, although Herz describes endless studies on humans and scents, she says nothing about the powerfully enhanced ability to detect odors experienced by many pregnant women. I remember kissing my husband when he came home from work and astounding him when I said, correctly, "You used that salad dressing again that I begged you not to eat--it has so much oregano and powdered garlic." The entire world seemed like an assault from a department store fragrance spritzer. I couldn't think; I could only try to avoid the next nauseating smell.
Herz writes that dogs can detect odors at concentrations 100 million times lower than we can: "This is the equivalent of being able to detect a drop of chocolate in a city the size of Philadelphia," she explains. Humans are actually wired for better smell ability than we have--about 65 percent of our genes for olfaction are no longer functioning. There was limited space inside our skulls and the genes giving us superior vision won out over scent.
I say this is all to the good. Herz observes that if all the genes coded for olfaction actually did work, "I am sure human culture, civilization, and our experience of reality would be very different from what it is now." No kidding. If we had a dog-like ability to smell, we'd all be abandoning our families to run to Philadelphia to find that drop of chocolate.
Speaking of which, unlike the sense of taste, which is hard-wired, our perception of what we smell is almost totally dependent on conditioning. Herz writes that newborns will smile if sugar is placed on their tongue, grimace at the taste of quinine, and purse their lips at a drop of vinegar. But "infants like the smell of feces and are equally indifferent to scents that adults view as negative or positive, respectively, such as rancid cheese and banana." It is culture, and personal experience, which teaches us what smells good or bad. She cites her own example of riding in the car as a child with her mother, when her mother detected the scent of skunk and said, "I love that smell!"--setting Herz up for a lifetime of skunk appreciation. (I remember first encountering the scent and thinking, What's the big deal? It's not so bad.)
She says that China lost its 2004 Olympic bid in part because public pit toilets left a lavatory smell hanging over the city that was unremarkable to its citizens but repulsive to the Olympic committee. It is because perception of scent is both cultural and personal that the U.S. Army has not been able to develop a universal stink bomb, a safe way of dispersing crowds. One person's "yuck" is another person's "yum."
Herz attempts to build the case that scent has a particularly powerful ability to induce and call up emotions. Of course, she cites Proust's tea-laden madeleine--which was actually a taste memory. (Those two senses are synergistic: Without a sense of smell, food tastes bland and flavorless.) She says the other senses can trigger emotions as effectively as scent, but that a scent-provoked memory is particularly emotion-laden.
I didn't find her case entirely persuasive, especially since the other day I heard a snatch of John Coltrane's Naima on the radio and found myself welling up with tears, carried back to my childhood, watching my late father in the living room pretending to play along to his favorite saxophonist. Perhaps the right scent could have sent me back just as well, but I doubt it would have been more powerful.
The emotions of scent are not just tied up in memory, but in mating. Herz presents interesting research about how our own body odor, unique as a fingerprint, is a powerful tool in attracting or repelling a sexual partner. She cites evidence that, despite our bathed and deodorized society, we still release enough molecules for women to judge the suitability of a man by his aroma. Our body odor is a manifestation of our immune systems, and what women find most delicious are men with immune systems complementary to theirs--thus less likely to share the same deleterious genetic traits. Herz does concede that the visual tends to trump the olfactory for men.
In a discussion sure to enrage many, she says odor-induced illness, known as multiple chemical sensitivities syndrome, or MCS, in which the sufferer becomes weak, nauseated, and dizzy when exposed to the offending scent or scents, is probably nothing more than a conditioned psychological response to a belief the perfume or "sick building" is making one sick. She also says that getting aromatherapy may be lovely and relaxing, but the scents inhaled have no physiological benefit. The good feelings induced are the result of believing in the therapy.
While The Scent of Desire didn't convince me that humans are wrong to think of the sense of smell as a lesser sense than sight or hearing, it is, like any one-subject volume, filled with intriguing bits of information. We all have known couples who have struggled with infertility, adopted a baby, and then the wife has found herself pregnant. Herz gives a reason for this phenomenon: "Baby sweat/body odor can increase a woman's fertility . . . Baby scent begets babies." It's also the case that we must literally wake up to smell the coffee; our sense of smell is turned off during sleep.
Herz acknowledges scents are enigmatic, ephemeral, and hard to describe. But she tells you probably as much as you would want to know about them, unless you are a beagle.
Emily Yoffe is the author, most recently, of What the Dog Did: Tales From a Formerly Reluctant Dog Owner.