What the Nose Knows - Avery Gilbert [40]
A 1996 U.S. patent describes a device to help the sniff-impaired. It resembles a double-ended turkey baster, with the bulb in the middle equipped with one-way valves. The user positions one end of the device over, say, a bowl of chili, then squeezes and releases the bulb, and it fills with air. Now the user inserts the other end in his nostril and squeezes again, forcing a bulb full of chili-scented air up his nose. The device is sort of an Elsberg self-blaster, a nose trumpet for the hard of smelling.
Boosting nasal airflow even improves odor perception in normal people. The Breathe Right nasal dilator was first marketed in 1993 to help reduce snoring by increasing nasal airflow, but got attention as an athletic aid the following year when Herschel Walker of the Philadelphia Eagles wore one for the first time in an NFL game—he had a cold. When Jerry Rice of the San Francisco 49ers followed suit, the Breathe Right gained locker-room cred, and commercial success followed in drugstores across the country. The dilator is placed on the bridge of the nose just above the fleshy portion of the nostrils, where it exerts a springlike action that prevents the sides of the nasal vestibule from collapsing inward during an indrawn breath. (The nasal vestibule is the space behind the opening of the nostril; it’s the finger-pickable part of the external nose.) Testing shows that wearing a dilator makes odors smell stronger, improves odor identification ability, and helps the wearer detect an odor at significantly lower concentrations. These benefits are the result of more air getting up into the nose. The nasal dilator increases the intensity of food aromas in the mouth but, weirdly, decreases the pleasantness.
THE ACT OF SNIFFING, overlooked by many scientists and politely ignored by well-mannered people, is critical to how we generate a mental image of the smellscape. The rapid sampling of odor-laden air is managed by a precisely timed interplay of sensory and motor function. In many instances, sniff improvement results in smell improvement. Seventy years after Charles Elsberg set out to suppress the sniff, we have finally begun to appreciate its value.
Even as it makes midsniff adjustments to the smell stream entering the nose, the brain is actively fine-tuning the mental impression it creates from an odor through a process called adaptation. Everyone is familiar with visual adaptation: after being in bright sunlight, it takes a minute or two for your eyes to adjust as you enter a darkened room. The reverse happens when you leave a movie theater in midday: the sunlight is unbearably bright at first, but gradually you adjust. Olfactory adaptation works on a similar principle: a new odor smells strong when we first experience it, but the longer we’re exposed to it, the more it fades into the background. In the extreme, the smell may be undetectable for a while.
It’s easy to overstate the practical importance of this phenomenon. Adaptation is a temporary change; it doesn’t permanently erase the ability to smell. Fragrances are not written in disappearing ink: if women stopped smelling an eighty-five-dollar perfume within a few days of buying it, the fragrance industry would have collapsed long ago. The extent of adaptation depends on the nature of the smelling being done. Perfumers I know insist they can only smell half a dozen fragrances before they notice a dulling of perception. For these professionals, olfactory fatigue is a real obstacle. They sample trial perfumes from blotters, five-inch strips of filter paper dipped in the liquid. The professional takes a quick sniff or two and moves the blotter away, ever conscious