What the Nose Knows - Avery Gilbert [29]
Freud caught influenza in the spring of 1889, at the age of thirty-three. The infection was severe enough to leave him with a persistent cardiac arrhythmia, so it could easily have affected his nose. In his letters to Fliess from 1893 to 1900, Freud often complains of nasal congestion with discharge of pus and scabs, both symptoms of sinus and nasal passage infection. Freud suffered from migraine headaches, which he treated with nasal applications of cocaine prescribed to him by Fliess. Fliess operated on Freud’s nose twice to remove and cauterize part of the turbinate bones. On top of all this, Freud smoked heavily; his typical rate in the 1890s was twenty cigars a day.
Freud’s nose was already a medical disaster zone when he hatched his smell theory in 1897, and my hunch is that he was already smell-impaired. When he wrote Civilization and Its Discontents in 1930, he was seventy-four years old and suffering from cancer of the jaw as well. In my view, Freud’s intellectual indifference to smells was the result of sensory deprivation—the gradual onset in adulthood of severe hyposmia. His ludicrous idea that smell was active in children but ceased to matter for adults had nothing to do with his feelings about Wilhelm Fliess. It was simply an overgeneralization of his unfortunate personal experience.
Our Rank in the Animal Kingdom
No doubt there is a vast difference in power in the sense of smell in both these animals [deer and dog] and in man; nevertheless, I do not think so meanly of man’s olfactories as some physiologists appear to do.
—W. H. HUDSON, On the Sense of Smell (1922)
After finishing my PhD at the University of Pennsylvania, I began working a few blocks away, at the Monell Chemical Senses Center. I received a fellowship to study there with Dr. Kunio Yamazaki. He had several lines of inbred mice used for cancer research; the lines were genetically identical except for a set of genes known as the Major Histocompatibility Complex (or MHC), which controls the body’s tissue-rejection response. They are the genes used to find whether a person is a suitable match as an organ donor. Yamazaki’s mice preferred to mate with individuals bearing a different MHC type apparently on the basis of smell. My plan was to study the behavior behind the odor-based mate choice using competitive mating experiments, where the female had access to multiple males of different MHC types.
Watching the mice choose mates, I became curious. Could humans detect the odor differences that were so apparent to the mice? Soon I was running my first experiment on human odor perception. I had blindfolded people sniff live mice in Tupperware containers with holes cut in the sides. Occasionally a mouse tail would get up someone’s nose; this seemed to bother some people more than others. The judges also sniffed tiny test tubes filled with mouse urine or dried fecal pellets. (Thankfully, no one inhaled a mouse turd.) For every odor source the results were clear: untrained humans could distinguish between the mouse strains based on smell alone. The uncanny scent powers of mice were well within human reach. I wrote up the results as a man-bites-dog story for the Journal of Comparative Psychology, and it eventually became one of the mostcited scientific papers I have ever published. By encouraging me to continue exploring human odor perception, it also led to my career in the perfume industry.
Deborah Wells and Peter Hepper discovered an even more impressive man-smells-dog story. They had dog owners sniff two identical blankets, of which one had been slept on by their pet and the other by an unfamiliar dog. The owners correctly identified their dog 89 percent of the time. The strength or pleasantness of the smell was not a factor, nor were non-doggy household odors.
Stories about the amazing ability of the canine nose highlight the dog’s talent and ignore how the feat is stage-managed by humans. (“Pay no attention to that man behind the curtain!