Your beloved grandmother wore Chanel No. 19; your favorite teacher loved Opium; your best friend in high school was crazy for CK Be. And today, whenever you get a whiff of any of them, your mind does Proustian backflips down the tunnel of memory. Instantly, you're happy.
That's because scent takes a unique route to our brains, says cognitive neuroscientist Johan Lundstrom of the Monell Chemical Senses Center in Philadelphia.
"Every other sense goes from the sensory organ -- the eyes, the ears, the tongue -- into the brain stem and to the thalamus, the switchboard of the brain, and then gets processed," Lundstrom says. But smell leapfrogs instead to the limbic system, which includes the amygdala (the seat of emotion) and the hippocampus (which governs memory).
Scents and Sensibility
Certain scents provoke nearly universal responses, at least within specific cultures, and no one knows exactly why or how this is so.
Some researchers believe the reactions are triggered by early childhood associations. But a study earlier this year at Ruhr University in Bochum, Germany, indicated a physiological basis for responses to jasmine (long reputed to be a natural antianxiety scent). Mice who inhaled it stopped racing around and sat quietly in the corners of their cages.
Jasmine enhances the mood of human subjects so much that they knock down 23 percent more pins when they bowl with the scent in the air, according to a study at the Smell and Taste Treatment and Research Foundation in Chicago.
Odors can also affect perception: Men in one foundation study guessed that women wearing the scent of pink grapefruit were six years younger than they were in reality; in another study, men thought women wearing spicy florals were 12 pounds lighter.
The psychological powers of scent have been wielded for centuries by alchemists, herbal healers, and perfumers. (Marie Antoinette is said to have gone to the scaffold with several vials of her favorite Houbigant scent tucked into her bosom for courage.)
But our emotions can be manipulated only up to a point, because the fragrance experience is more complicated than simply pushing button A to get Pavlovian reaction B. Personal memories in particular can override more common associations, Lundstrom says.
Lavender and vanilla are known for their calming properties, but if your high-strung mother wore them, they may never feel tranquil to you. Lundstrom himself often works with phenylethyl alcohol, a compound that smells like roses. Most people find it lovely and romantic, "but I now associate the scent of rose with long hours in the lab."
By the same token, we respond positively to all kinds of olfactory madeleines that trigger pleasant memories. Perfumer Alexandra Balahoutis of Strange Invisible Perfumes, based in Venice, California, once concocted a fragrance meant to evoke a young woman's trip to Italy.
In addition to native plants like Sicilian orange blossom, Parma violets, and basil, it contains tobacco and musk. "I wanted to encapsulate not just Italy or Florence, but the experience of discovering them -- being a young girl and being delighted and corrupted by a way of life, smoking cigarettes and drinking espresso."
When perfumer Jane Hendler of Ajne in Carmel, California, meets with new clients, she asks them to fill out a two-page form listing their favorite colors, music, and season. But most important is the question: "What's going on with you, and what are you looking for this fragrance to do?"
Many women report a broken relationship and the trust issues that go along with it, Hendler says. For healing bruised hearts, she recommends fragrances containing rose or linden blossom, based on a long tradition rooted in ancient folk medicines.
For those who are anxious, grieving, or having trouble sleeping, she suggests bergamot -- "almost a natural Prozac" -- or other citruses. "And someone who is too flighty needs the woody oils for grounding -- like amber, sandalwood, cedar, labdanum, and oak moss."
Obviously no perfume can replace a good shrink, but fragrance is still powerful enough to serve as a kind of jump start when you need it. "It can help you create a persona or a personal environment," says perfumer Dawn Spencer Hurwitz of DSH in Boulder, Colorado.
"Elton John's backup singers used to come into my shop and get a fragrance made for each of their costumes. I also worked with an upright bass player who had the scent come out of his bass to help him focus and get into the zone."
Hurwitz herself uses a fragrance containing frankincense, sandalwood, and rose to accompany her meditation practice. The combination was soothing and contemplative by design, but even more than that, it became imprinted on her brain as a cue to meditate -- a process that in her experience takes from two to four weeks of regular use to cement.
Once the association was made, she started carrying the meditation fragrance in her car, as a way to stay calm in the face of traffic and bad drivers. She has clients who bring tiny vials of fragrance on the subway to sniff away the crowds and stress, or who breathe in instant groundedness at the office.
All perfumers try to appeal to consumers' emotions -- through not just the scent, but its color, its name, and the shape of the bottle. Perfumers originally used the oils derived from flowers, herbs, and the leaves, roots, seeds, and barks of other plants, as well as the secretions of animals.
But in the late 19th century, scientists realized that they could mimic expensive botanical and animal ingredients in the lab and could even duplicate certain smells (including gardenia, lily of the valley, apple, peach, and plum) that had defied easy extraction from plants and were therefore rarely found in natural fragrances.
In the 1920s, Chanel No. 5 became the first fragrance to use a high concentration of synthetics. Since then, most ingredients in mainstream scents -- including gorgeous re-creations of every flower in the garden -- have been manufactured. Natural perfumery, based entirely on botanicals and some natural animal essences, is a reaction against this trend.
Which is better? That depends on what you're looking for. Natural perfume lines are harder to find than mainstream brands, and until fairly recently they tended to be unsophisticated -- think of those eau de hippie essential oils from the health-food store, like patchouli.
That changed in 2004 with the publication of "Essence and Alchemy," by perfumer Mandy Aftel of Aftelier Perfumes in Berkeley, California, who pioneered the art of blending traditional oils into modern fragrances and founded the Natural Perfumers Guild. One or the other isn't necessarily better, even for sensitive folks; you can just as easily have a reaction to a lab-made scent as to something from the earth.
The main difference is volatility. Synthetics are less complex at the molecular level, says psychologist Avery Gilbert, author of "What the Nose Knows." That means that "what you smell when you first put it on is what you smell two hours later."
Synthetics also tend to smell similar on everybody, while naturals interact far less predictably with the oils of the skin. They can smell very different depending on the wearer's hormones, diet, or individual chemistry. None of this affects the ability of fragrance to change our moods; from the department store or the garden, scent is transformative and can have a powerful effect.
It's not exactly eye of newt and toe of frog, but for most of us, fragrance does cast a spell.