Ten Minutes with Rachel Herz: On Smell

When was the last time you stopped to smell the roses? No, really! Our sense of smell is something many of us take for granted, but this sensation is more powerful than you may think. “It literally filters through all aspects of our existence,” explains neuroscientist Rachel Herz, “and the more we deliberately use our sense of smell…the better our brain health is, and even the general health of our bodies.” That’s why Herz regularly stops to sniff her surroundings—even the roses.

Smell also plays an important role in art, with many artists using scent as a way to prompt questions. Made of 48 bales of hay, Cildo Meireles’s Thread fills the room with an unexpected scent and invites us to reflect on the materials we value. Borrowing a familiar object, Takako Saito’s Smell Chess, Liquids and Spice Chess imagines a new way to play chess—one where our nose is just as important as our brain. These artworks encourage us to slow down and engage our senses. As Herz reminds us, when we stop and smell the metaphorical roses, “it can really ground us and bring us into that moment.”

When we smell, what we’re actually doing is perceiving the chemicals that are in the air that we breathe.

Basically what’s happening is that there’s chemicals floating through the air constantly. And many of them have a quality to them that allows us to be able to perceive them as smells—although not all of them do—and those chemicals that are potential scents bind with the olfactory sensory neurons that are in fact sitting out in the open on the neural epithelium that is directly at the top of our nostrils.

If you could stick your finger up high enough, you could technically touch these sensory neurons. And that’s actually something that makes a sense of smell different from our other senses, that the neurons for detecting the stimuli in the outside world are directly, actually out there.

This also produces some problems—the problems being that these sensory neurons get killed off by the environment, by the toxins and everything else, pollution and so forth. But these neurons are also continuously regenerating. In fact, about every month or so, we technically get a new nose, as long as our sense of smell is healthy and functioning normally.

But in any case, when the chemicals then bind with the sensory neurons, they do so in a particular way for each different scent that we perceive. There’s a firing of neurons in a specific frequency at a specific time across the space of the epithelium in a particular pattern, and that particular pattern is unique to how we perceive that scent.

For instance, the scent of rose produces a specific pattern that’s different from lemon, that’s different from skunk, that’s different from cinnamon and chocolate and so on.

Anytime we smell anything, it elicits some level of emotional response, whether it be just a vague, “I kind of like this, I kind of don’t like this.” And it can go as deep as triggering the traumatic flashback for someone with PTSD, to bringing us to a state of sublime calm and joy or ecstasy or whatever the case might be just as a function of what that particular scent means to us as a function of our prior association with it and the emotion that is grounded to it.

The reason that a certain scent may trigger a specific emotion is actually to do with that individual’s past history with that scent. There’s a couple of things that go into that.

First of all, there’s the culture that you grew up in and how various scents were presented to you and what they meant. For instance, is the scent of rosewater part of cooking for you and part of food that you eat? Or is the scent of rose purely something that you would smell if someone gave you a flower bouquet or something that was potentially in a perfume?

Then we have our own personal experience with a scent, which will supersede any cultural background that we may have grown up with. That is specifically what we experienced when we, usually for the first time, encountered that scent, because the first experience we have with a scent is the one that gets most tightly bound to its meaning. And so whatever we experience first is usually what it’ll always bring us back to, which is why many scents really bring us to childhood.

Whatever that scent means to us personally is going to be what that scent evokes.

Interestingly, we actually smell through two different roots. We smell from our nostrils, which is what we typically think of when we’re thinking about smell, but we also smell from our mouth.

We sniff through our nostrils, it travels through the nose to the patch of epithelium. And then we inhale while we’re eating, and the aroma molecules that are in our mouth from the food that we’re chewing go to the exact same location through this open airway system in the back of the mouth.

It’s, in fact, our experience of flavor, which is actually very simple—just salt, sour, sweet, bitter, and umami—plus the aroma of whatever it is that we’re consuming at the same time that gives us our perception of food, and the brain is what’s putting it together.

We always say taste, but really almost all of it comes from smell. For example, if you didn’t have a sense of smell and you bit into a piece of chocolate cake, all you would taste is sweet. Or if you cut into a juicy steak, all you would taste is salt.

Our sense of smell actually augments and synergizes with our sense of taste to make flavor more intense.

I would just really love that people realize how smell alters their experience of life.

I know from many people who have contacted me what the trauma and tragedy of losing the sense of smell is and how it’s just absolutely shocking to them the way that their lives have changed. And so I really try as much as possible to pay attention to smells around me and to really appreciate them.

Every day when I’m outside, for instance, walking my dog, if I pass anything that is fragrant, I will stop and sniff at it. In the house I have a set of smells on my desk that I try to smell. When I’m cooking, I get into the spice jar and so forth with my nose, and of course, when I’m eating, ground savoring the flavor and really experiencing the fragrance, whatever it might be at that moment.

I am quite conscientious about doing this, not just because it gives me pleasure and it’s fascinating to me, but in fact, the more we deliberately use our sense of smell, the better it becomes. And better that our sense of smell is, the better our brain health is, and even the general health of our bodies.

No other sensory system has as much emotional and evocative potency and is able to ground us in our bodies, and that can bring us into ourselves more purposefully and more specifically than I think any of our other sensations.

If we just for a second pay attention to what it is we’re smelling—because most of the time it’s just filtering through the background—but if we stop for a moment and pay attention to the scent that is around us, it can really ground us and bring us into that moment.