Like many Santa Feans, I live in a home built by local Living Treasure Allen Stamm. And like many Stamm homes, mine runs cold. There's a fair bit of history embedded in these vigas, and every winter when I crank up the heat, the oak floors stir and the baseboards burble and creak. Roused are the ghosts of cedarwood fires, Christmases past, and the family who lived here for
50 years before I bought the place; the house exhales into itself like a living thing. It's as pervasive as the smell of rain against asphalt — and I love it.

Smell is my favorite sense. Experience is a catalog of synaesthetic snapshots, sound clips and amuse-bouches — but it is olfaction that rules the archives: summer's first steely blast of brine and American car exhaust, the miasmic security blanket of cigar smoke and steaming clams in the family's dark seafood restaurant; the unmistakable trail of chaos and patchouli that a friend always left in her wake. Like Pavlov's pup, my impulses are bound to sensory and adrenal memories.

Sensitivities to certain aromas are thought to be genetic, such as the faculty that susses out the marzipan-redolent topnotes in cyanide. It's taken a few million years, but for most of us, over half of the thousand or so of our genes for honing our smell receptors have stopped working. Some of these genes, such as OR11H7P, which determines our ability to consciously smell sweat, mysteriously continue to function in some people. Unconsciously, our noses know things we can't even begin to understand. In Swiss scientist Claus Wedekind's revelatory 1995 study, the sweaty T-shirts worn for two days by an assortment of unshowered men were then given to a group of women who were asked to sniff the shirts and rate them in order of most and least appealing. Women were consistently drawn to the smell of the men whose gene families were most distant from that of the sniffer, and vice-versa — shirts from the most genetically similar men smelled the worst.

I've long been fascinated by the sense of smell and its impact on taste, health, the environment and human behavior. What determines food preferences and prejudices, how they evolve over the course of a lifetime, and how they are affected by physiological changes like pregnancy and illness? Aside from familiarity, what makes the strong flavor of a stinky cheese irresistible to one person while the next person favors bland foods, or spicy fermented foods, or simply doesn't care one way or the other?

It's easy to argue that taste is subjective, but some odors and flavors are incontrovertibly unappealing on a larger scale. For instance, though it's said that vegetarians have a milder body odor than nonvegetarians, when the Japanese first encountered Westerners, they were so repulsed by their smell (the result of a diet richer in animal fat) that the term bata-kusai or "butter-stinkers" was devised to describe them.

Then there's the matter of tobacco use. Smoking upsets the sensitive balance of taste receptors and the nasal epithelium. Michael Bauer, executive food and wine editor of the San Francisco Chronicle, writes skeptically, "I've always contended that smoking dulls the palate, but I've been told by professionals who smoke that it makes them more attuned to various flavors." Smoke is no longer a common offender in the dining rooms of American restaurants, but I'm actually less concerned about passive smoke affecting my experience than with the sous chef's smoking habit being the reason for an overseasoned dish.

Clinically, I have suspected certain medical conditions guided solely by a distinctive odor. Certain diseases and some medical treatments produce unmistakable smells. Another thing I have seen clinically is the complaint of chemical sensitivity, something toward which I have not always been sympathetic, having dismissively chalked idiopathic environmental intolerances up to the nebulous realm of metaphysics. In restaurants, I had seen people occasionally use the threat of an allergic reaction as a means of justifying ordinary dislikes. Later, I began to understand how much I had oversimplified the issue.

Legitimate chemical allergies do exist, and so do strong negative reactions that may not culminate in actual disease. For example, I hate most fragrances and will go out of my way to avoid them, but it won't kill me to cross the detergent aisle of a regular grocery store once in a while. But I'm all for the banning of perfume and cologne in restaurants.

Nouf Al-Qasimi is a freelance writer living in Santa Fe. Send e-mail to food@q.com.