The Mnemonic Sense: The Beginning

The other writers on this blog all approach the subject of perfumes with at least a year's worth of sniffing experience. I, however, am a complete newcomer to perfume appreciation. (To this end, I would like to thank Dain, who has made these experiences possible by allowing me access to her stash, as well as helping me get some samples of my own to try.)

That is not to say that I am new to the act of smelling. My life, like any other, has been full of smells that intermingle and forge unlikely alliances amongst themselves—as smells are wont to do—to create a strange tapestry: Korean fermented fish sauces and a tomato patch on a hot stuporous day share an undertone of nutrient-rich decay with the smell of the sea. And all of us have experienced the feeling of being suddenly transported into our memories, as if by a time machine, when encountering a familiar scent, even if we ourselves never consciously made any association between the two.

In fact, this is perhaps the most ironic feature of smell, that we often don't know what we are smelling but still manage to recognize it. Unlike sight and hearing, which are the two senses we mainly rely on for information about the outside world, scent is very much a gray area for us.


A "Sensory Homunculus": a model of how we would look if the size of each body part grew in proportion to the distribution of sensory nerves.

Scientists use the term "limbic system" to denote, as vaguely as possible, parts of the brain that govern functions thought to be related—such as long-term memory, spatial orientation, and motivation (including appetite and sex drive) along with smell. These "limbic" functions are considered more primitive and at the same time, more crucial to basic survival than the "higher functions" of consciousness and reasoning (governed by the neocortex). Most limbic structures are therefore cushioned off in the core of the brain, away from potential external threats, and along with memory, scent is one of the last senses to be lost in the events of brain damage. (There is one exception: degeneration disorders like Parkinson's and dementia that affect memory seem to take away the sense of smell first.) And of course, this also means that animals have proportionally larger limbic systems compared to humans, in whom the cerebral cortex makes up the bulk of the brain.

This means that animal brains are, generally speaking, much more simple: all the machinery is completely formed by birth, which is how new calves and foals are able to not only walk, but run to keep up with the herd just hours after birth. This is not possible with the human brain, which is so complicated that if human infants were to likewise be able to walk and function as members of society from birth, the gestation period would stretch to years, and infant heads would grow so large that childbirth would literally become a death sentence for both mother and child. Instead, humans must rely on the knowledge provided by experience, recalled through memory, and organized through reasoning to make for our underdeveloped instincts. A marvellous system in its own right, possibly, but one that complicates relatively simple acts, like smelling.


Perhaps this is why smell is not of such all-consuming importance for us as it is for most other mammals, many of for which smell is the main sense through which they "see" their world. Quite simply, they are born knowing quite unambiguously what smells like what, without the cognitive cartwheels a human brain has to go through before identifying a scent or isolating a single component from it. Of course, the difference may lie in the nose itself, but and more because we are cognitively detached from our senses, relying on our brains to imbue our perceptions with meaning. Such conscious thought is focused and therefore necessarily narrow in scope, which dramatically—and tragically—pares away much of the full sensory reality available to us.

This flaw in our brain structure, more than any defect in the way our noses are structured, is why we often have so much trouble identifying notes and breaking down a perfume into its component parts... but it is also what drives us to create this game around the sense of smell, and wax poetic over perfumes (without the aid of a poetic imagination, a smell is just a smell, after all). It was the heavily purpled (and sometimes self-contradictory) babble of perfume reviews that first drew me in to perfume appreciation, but most of the reviews left me completely unprepared for the actual experience of smelling what was described. Instead of "the poignancy of violet and iris petals weighed down by raindrops," I got a candy shop and dawn lifting to the sound of reed flutes (jump to 8:08 below) from Après L'Ondée, and instead of the "quirky yet dreamlike mixture of smoke and leather and circus animals and woody cinnamon sweetness" I expected from Dzing!, I got absolutely nothing.*


Our experience-built brains are also the reason why we can never agree on the analysis of a particular scent. Smells are inextricably bound up with memory in the learning process. Since every life history is different, each brain is likewise totally unique... and therefore, each person will break down a scent a different way in his mind. Those familiar with the scent of strawberries** will consider it a single coherent scent element: in actuality, the scent of strawberries is comprised of a whole ensemble of chemicals ranging from the obvious choice of ethyl methylphenylglycidate (better known as "strawberry aldehyde") to the less intuitive choice of skatole (which, on its own, smells just as its name implies) to accentuate the feeling of ripeness. Conversely, the scent of a single specific molecule can register as a scent of dizzying complexity when minds attempt to make sense of a totally new stimulus by feebly grasping around in their banks for analogies by which to arrive at an approximation: even Luca Turin must use analogy to describe the smell of the compound oxane as "a shimmering mixture of sweat and tropical fruit, with a 'green' marijuana-like note." A beautiful description, but surely an injustice to oxane—considering its chemical identity, it should be a "note" in its own right.

Most of the individual notes that I have learned to distinguish recently are base notes, used for their ability to blend well with skin and with other scents, unifying the brash, opinionated, eccentric character of many top and heart notes into a seamless whole: for this reason, they are often difficult to distinguish each on their own. And when the perfume is ambiguous, seemingly not conforming to any one genre, the kind of base notes used will often provide a clue as to the fragrance's final classification: vetiver, for instance, while used in many green or fresh perfumes, is not often found in an oriental composition, while the reverse is true for ambers.


"Breath Leaves" by Giuseppe Penone
Vetiver is derived from the roots of a perennial grass, native to India, where it is often used in woven mats hung at the entrances of a house for a cooling effect, and to purify drinking water. Its odor is often described as green, balsamic, woody, smoky, or "bug spray," and lends the musty smell of a forest floor to "earth" flightier compositions. I personally love the tranquility that vetiver imbues to the composition—though it can indeed take on the virulent quality of bug spray when not used thoughtfully—and it loves me back: this stuff lasts well beyond twenty-four hours on my skin, regardless of what composition it's used in.


Musks and aldehydes are like twin brother and sister, two facets of the same coin, polar opposites that nevertheless share the same genetic makeup and origins. Aldehydes create a cloud that projects high into the stratosphere and obscures the contours of the landscape like a morning fog, without actually alerting us to their presence: generally, the best clue is a sort of soapiness or powderiness, identifiable from a distance but impossible to pin down for closer observation. Where aldehydes are diffuse and extroverted—social butterflies—musks are homebodies that cling to the skin, but they are similarly elusive. It doesn't seem so much a scent as a kind of lingering presence: the feeling of being close to warm skin that almost always escapes our notice except in retrospect. And clean or dirty, musks and aldehydes both share a certain brittleness: aldehydes that of fine threadlike crystals of asbestos, musks that of the bitter astringency that any sort of powder leaves in the mouth, like chalk dust.


Woods and incense inhabit a sort of intermediate territory in between the forest-aroma of vetiver and the denseness of a musk. Whereas vetiver is an extract of the fresh root and therefore a decent recreation of the living essence of the plant, wood and resin scents are more of an abstraction: though wood takes something of their essence from the tree itself, its smell is also created through aging (time) and mingling with the open air, which gives a musty quality to what was once a live, breathing thing. Wood scents (and incense notes, which are often derived from wood or the resins from wood) are the scents of a tree seen through memory.

Obviously this is only a partial list of base notes, definitely biased toward the scents I personally favor: I've left out oakmoss (which I haven't been able to sniff in great quantities, as of yet), leather, amber, and other animalics like civet and castoreum (not used very much in modern perfumery in any case). There is also iris (another favorite of mine), which is traditionally classified as a heart note, but often acts as a bridge between heart and base notes due to its density.

In any case, as the title states, this is simply the beginning. I expect many more changes of direction, disappointments, and revelations are in store for the future.

* The “descriptions” here aren’t sampled from any one review in particular, but cobbled together out of bits and pieces sampled from various reviews across the perfume blogosphere. It's a tendency that's easy to make fun of, but due to our low sense of specificity when it comes to smelling, it's also a very easy trap to fall into, as I just proved by turning around in the same breath and coming up with my own purple prose.
** Incidentally, I've always sensed a note reminiscent of strawberries in ripe sweat... or is it that I detected ripe sweat in strawberries? I've not heard anyone else speak of such an association, but then again, I've also tasted banana and coconut in overbroiled mackerel. I'm interested in hearing about other people making mental connections between two scents that seemingly should have nothing to do with each other.