What the Nose Knows: The Science of Scent in Everyday Life by Avery Gilbert Page B
Book: What the Nose Knows: The Science of Scent in Everyday Life by Avery Gilbert
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Authors: Avery Gilbert
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detection rate was 61 percent for BACs between 0.10 and 0.15 percent). In the most rigorous study on the topic, all variables except odor were eliminated: test subjects were hidden behind a screen and breathed at the officers through a tube. The police participants were all highly experienced and trained as Drug Recognition Experts. Even so, test performance was highly variable across officers. As a group, they detected breath alcohol 85 percent of the time at BACs of 0.08 percent or more, but caught it only two-thirds of the time at lower levels. An officer’s ability to estimate the intensity of breath alcohol odor was no better than chance.
T HAT POLICE OFFICERS, like everyone else, show a wide range of olfactory ability comes as no surprise to smell scientists. That their abilities should be granted special consideration by judges and juries is another matter. Doty and his colleagues argue that skepticism is in order when marijuana is said to be “in plain smell.” Sensory claims by police are least substantiated when it comes to fresh, unburned marijuana. Yet this is just the circumstance where courts have given greatest credence to a police officer’s nose—no corroborating evidence is needed. Doty’s study has already been cited by the defense in a drug case in federal court. (A police officer with no training in pot aroma claimed to smell immature marijuana plants in an unvented grow house from a long distance away.) Can trained police officers outsniff civilians? Probably. But according to Doty, this has yet to be scientifically documented. Helen Keller would expect better from the Federal Bureau of Aromatic Specialists.
CHAPTER 4
The Art of the Sniff
The smoke of my own breath;
Echoes, ripples, buzz’d whispers, love-root, silk-thread, crotch and vine;
My respiration and inspiration, the beating of my heart, the passing of blood and air through my lungs;
The sniff of green leaves and dry leaves, and of the shore, and dark-color’d sea-rocks, and of hay in the barn…
—W ALT W HITMAN,
Leaves of Grass
S OME SMELLS ARE MORE SUBTLE THAN OTHERS. T HEY float up the nose on the tidal rhythms of normal breathing and may not reach conscious awareness until minutes later. When we want to pay attention to an odor, we don’t wait for the next lungful of air—we capture it with a sniff. Sniffing is an odd behavior—it has no analog in vision or hearing. (Dogs, mice, and deer can rotate their external ears to focus on sounds; we can’t.) Sniffing is ignored by students of “body language.” It can be done covertly, and in polite company it usually is; sniffing is considered rude, and audible sniffing is downright vulgar. It takes an uninhibited, bumptious soul like Walt Whitman to draw attention to it, much less revel in it. But there is no getting around it; sniffing is essential. Whether one is tracking down a dead mouse in the basement or savoring a newly opened bag of Doritos, the sniff is the prelude to a smell.
The purpose of a sniff is to get scent molecules to the place where we can smell them. The question that took philosophers and scientists thousands of years to answer was, Where exactly does smelling happen? Some ancient Greek philosophers argued that it took place in the nose, but the sievelike appearance of the cribriform plate—a bone at the base of the skull just above the nasal passages—led others to speculate that odor particles made their way directly to the brain through these tiny holes. In this view, the nose is a merely a tube and the brain is the sensory organ. The ancient nose-versus-brain debate wasn’t settled until 1862, when a German anatomist discovered the olfactory nerve cells in a cleft high in the nasal passage. Smell—at least the first physiological contact with odor molecules—clearly happens in the nose. The holes in the cribriform plate are there to allow nerve fibers from the sensory cells to reach the brain.
Because the olfactory cells were tucked away in
T HAT POLICE OFFICERS, like everyone else, show a wide range of olfactory ability comes as no surprise to smell scientists. That their abilities should be granted special consideration by judges and juries is another matter. Doty and his colleagues argue that skepticism is in order when marijuana is said to be “in plain smell.” Sensory claims by police are least substantiated when it comes to fresh, unburned marijuana. Yet this is just the circumstance where courts have given greatest credence to a police officer’s nose—no corroborating evidence is needed. Doty’s study has already been cited by the defense in a drug case in federal court. (A police officer with no training in pot aroma claimed to smell immature marijuana plants in an unvented grow house from a long distance away.) Can trained police officers outsniff civilians? Probably. But according to Doty, this has yet to be scientifically documented. Helen Keller would expect better from the Federal Bureau of Aromatic Specialists.
CHAPTER 4
The Art of the Sniff
The smoke of my own breath;
Echoes, ripples, buzz’d whispers, love-root, silk-thread, crotch and vine;
My respiration and inspiration, the beating of my heart, the passing of blood and air through my lungs;
The sniff of green leaves and dry leaves, and of the shore, and dark-color’d sea-rocks, and of hay in the barn…
—W ALT W HITMAN,
Leaves of Grass
S OME SMELLS ARE MORE SUBTLE THAN OTHERS. T HEY float up the nose on the tidal rhythms of normal breathing and may not reach conscious awareness until minutes later. When we want to pay attention to an odor, we don’t wait for the next lungful of air—we capture it with a sniff. Sniffing is an odd behavior—it has no analog in vision or hearing. (Dogs, mice, and deer can rotate their external ears to focus on sounds; we can’t.) Sniffing is ignored by students of “body language.” It can be done covertly, and in polite company it usually is; sniffing is considered rude, and audible sniffing is downright vulgar. It takes an uninhibited, bumptious soul like Walt Whitman to draw attention to it, much less revel in it. But there is no getting around it; sniffing is essential. Whether one is tracking down a dead mouse in the basement or savoring a newly opened bag of Doritos, the sniff is the prelude to a smell.
The purpose of a sniff is to get scent molecules to the place where we can smell them. The question that took philosophers and scientists thousands of years to answer was, Where exactly does smelling happen? Some ancient Greek philosophers argued that it took place in the nose, but the sievelike appearance of the cribriform plate—a bone at the base of the skull just above the nasal passages—led others to speculate that odor particles made their way directly to the brain through these tiny holes. In this view, the nose is a merely a tube and the brain is the sensory organ. The ancient nose-versus-brain debate wasn’t settled until 1862, when a German anatomist discovered the olfactory nerve cells in a cleft high in the nasal passage. Smell—at least the first physiological contact with odor molecules—clearly happens in the nose. The holes in the cribriform plate are there to allow nerve fibers from the sensory cells to reach the brain.
Because the olfactory cells were tucked away in
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