What's That Smell?

   Some studies are showing that people generally rate smell as the least important of the five senses as compared to the other four of touch, taste, hearing and sight (the latter are rated the two most important).  Yet Bianca Bosker would disagree; her book on sommeliers titled Cork Dork, takes a look at the world of wine tasters but goes much deeper, her journalistic side wondering what exactly is it about our olfactory senses that can make us at times seem quite primitive (the size of our olfactory bulb in our brain is about the same as that of a rat) and yet so advanced (some researchers say that our brains use much more of its abilities for that sense alone).  True or false, it would appear that anyone's sense of smell can be trained and sharpened to improve, although perhaps not quite as finely as those who work in certain industries such as those searching for new fragrances for perfumeries ?  As a piece on smell in the New Yorker some years ago wrote: The tongue can detect only five tastes, salty, sweet, bitter, sour, and a taste whose receptors have only begun to be identified: umami—the savory, brothy sensation that is amply present in Parmesan, seaweed, and ripe tomatoes.  All other taste sensations are really smells, as a very simple experiment will confirm: all you have to do to prove it is hold your nose while you taste something.  So taste is mainly smell, and smell is a profound mystery.

   As it turns out, 25% of the population are "super" tasters, she says, jumping back to wine and sommeliers; but does that mean that they are also super smellers?  People with Parkinson's are said to begin to lose their sense of smell, and it is now thought that our ability to smell or not smell might be built into our DNA and that we all have smells that we simply cannot detect (but that others can)...think color blind but "smell" blind (she also writes that an estimated 6 million people in the U.S., the size of the city of Los Angeles, have lost their sense of smell entirely, a condition called anosmia).  On the other side of the coin, a 2014 study which appeared in Science wrote that we humans have the ability to detect nearly a trillion different odors, far more than our sense of hearing (half a million different tones) and our sense of color (several million).  But here's that argument...the majority of our olfactory genes seem to remain dormant (for you chemists and scientists out there, the more descriptive report comes from the National Institute of Health which begins: Olfactory receptors (ORs), the first dedicated molecules with which odorants physically interact to arouse an olfactory sensation, constitute the largest gene family in vertebrates, including around 900 genes in human and 1,500 in the mouse.)  But author Bosker notes that a surgeon, Samuel Pozzi, wrote the debateable theory that our smell decreased because of evolution: Animals were quadrapeds, a position essentially favorable to the exercise of smell.  The primate rose up, man lifted his head forever away from the earth and directed his sight parallel to the horizon.  The hegemony of the visual sense substituted itself for that of olfaction...Is it not curious that the anatomist can legitimately link to this first fact, so apparently simple, the development of the frontal lobe?  Is it no less curious, from the same point of view, to discover in man's brain the vestiges of that dethroned organ, the limbic lobe.  Instead of forming an imposing unit, it is reduced to the state of fragments, barely linked to each other; in other words, a collection of debris.

   So are we indeed losing our sense of smell?  It's something she ponders as she writes: ...Odors, unlike sound waves, are chemically transmitted.  Molecules float off the surface of whatever we smell and into our bodies.  And when she asks Richard Dory (one of the "world's foremost experts on the chemical senses" at the Monell Center) on what we can do to enhance smells, she is taken aback at his quick response...cocaine: LSD might be better, he continues.  I've never tested myself on LSD.  But it certainly changes vision, so it probably changes taste and smell too.  When you manipulate the neurotransmitter systems with drugs, you could probably alter a lot of these things...But there aren't good studies on these things.  Whatever your view on that, she wonders if that might indeed be possible, pointing out the med student in the book, The Man Who Mistook His Wife for a Hat by the late author and neurologist, Oliver Sacks (I briefly touched on this in an earlier post).  After taking a series of drugs and hallucinogens, he: ...awoke to "a world in which all other sensations, enhanced as they were, paled before smell...I had never had much of a nose for smells before, but now I distinguished each one instantly -- and I found each one unique, evocative, a whole world," the student recounted.  He could pick up identities --and moods-- of his friends and patients just by their scent, and tease out the distinct aroma of every street and store in New York.  Neuroscientist Johan Lundstrom told author Bosker that the scent of women's tears "has been shown to decrease sexual arousal among men (and that) we can differentiate healthy strangers from sick individuals based solely on their body odors." She adds: Though we're largely oblivious to it at a conscious level, we exchange social information with each other via smell.  Johan's work has determined that humans can distinguish the body odors of twenty somethings from octogenarians; of friends versus relatives; and of boyfriends versus platonic male friends...One of his studies found that as women fall more in love with their boyfriends, they become worse at identifying the body odors of other men: Romantic love alters women's sense of smell to deflect attention "away from potential new partners," effectively binding them more intensely to their mates.  Ages ago, the guy in the next apartment to me claimed that he used to be a hit man for the mob and told my roommate and I that he could always smell "fear" on his victims (we tossed aside his flamboyant stories until some 25 years later we learned he was shot "mob style" as he left a bar...gulp).

    So if all of this true, that our noses are a much more finely tuned sense than we realize (or at least, capable of being a finely tuned one), imagine the world that other animals encounter as their receptors genes dwarf ours.  Take this excerpt from a paper at Hanover College: There are approximately 20 million olfactory receptor neurons in the human nose.  Although this is more sensory neurons than for any other human sensory modality, it is much fewer olfactory receptor neurons than seen in other species.  Dogs, such as bloodhounds and Basset hounds, have as many as 10 times more olfactory receptor neurons than we do.  Grizzly bears may even have more olfactory receptor neurons than dogs. Pigs also have large concentrations of olfactory receptor neurons.  The density of the olfactory receptor neurons in these species gives these animals enormously sensitive senses of smell.  Grizzly bears can detect the aroma of meat from nearly 20 miles away.  Bloodhounds can detect the presence of a specific animal even if it passed by a location several days earlier.  Pigs are trained to detect truffles buried underground and are still better than mechanical detectors.  Species, such as pigs, bears, and dogs, that depend heavily on smell are called macrosmatic.  Humans, who are more dependent on vision and audition, are considered microsmatic, regardless of the importance of olfaction. 

   Disneyland and other parks have experimented with this, one of their rides adding smells as you visually pass through orange groves or fly over the ocean (the experimental world of such "smelly vision" went away but was targeted for our televisions and computers).  And the more one types in words such as "olfactory" and "sense of smell" and "nose," one can sees the increasing amount of studies now making news as this tossed-aside sense now appears to scientists to play a larger role than we imagined, a step up from the pheromone studies of moths and other animals.  In her book, author Bosker mentions one of the main rules of sommeliers is to not wear any sort of fragrance lest it ruin their sense of smell when opening and tasting wines.  Imagine if our own sense of smell was that sensitive and not bombarded by the daily scents of detergents and deodorants and "refreshing" sprays...how much more would we enjoy our dinners?  Why we could all become as joyous as a Samurai Gourmet (a delightful series on enjoying food).  It's something to think about...as the saying goes, The Nose Knows.