You stink, but don't take it personally. Every human being has a distinct smell that says a lot about your diet, your health, even your emotions.
Access to many memories, and even information about our health, is right under our nose, journalist Jude Stewart says.
She puts one of our least appreciated senses front and centre in her book, Revelations in Air: A Guidebook to Smell.
Photo: Živa Trajbarič/Pexels
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Stewart’s normal beat is the visual world and she’s written two books on graphic design and colour. She tells Jesse Mulligan she started to get a bit tired of all things visual.
“I stumbled into an art exhibit that was all around smell and I found it so transporting, upsetting, and exhilarating. All these things and I couldn’t put words to why I felt that way. I thought, this is incredibly powerful and smells are pretty much everywhere. So I became curious and dove down the rabbit hole and came up with a book.”
While she won’t be wearing a blindfold and abandoning the visual world, she says so much of our lives are mediated through screens.
“It doesn’t seem real anymore. If you’ve ever had something like a car accident happen right in front of you, you feel like you’re watching a movie, you don’t feel present. I guess I was looking to locate myself back in my body and think about the ‘here’ in the world.”
Stewart says smell signals are sent straight to the amygdala and hippocampus which control both emotion and memory and she says there’s a good reason for that.
“If you think about why smell exists, it’s sort of an extension of our body’s defence systems. What you’re doing is sensing chemicals in the air that might represent a threat or an opportunity. If there’s a fire off in the distance, you want to smell the fire before you come upon it. If you want to eat food but the food doesn’t smell right, you want to know it’s off before you start eating it.
“This is the reason why I say in the book that smell is very judgey. If you have an experience with a smell that let’s you know this is a bad smell, you will not forget that. It is very tied up in memory for that reason.”
And the nose isn’t the only place that picks up those smells.
“When we think about olfactory sensors, we’re thinking about them mostly being up in the nose but, in fact, olfactory sensors are located throughout our body and scientists are now figuring out when they exist and their reason for existing, as far as we can tell, is the same reason as the nose, they’re sensing chemical changes.
Photo: Penguin Books
“An example would be your kidneys or stomach can sense that you’ve had an especially rich meal, if you’ve had a rich meal your body wants to generate more chemicals to process that meal, so that’s a difference in chemicals being sent by an olfactory receptor.”
Stewart says we all have our own unique smell when we strip back the clothing, the soaps and the perfumes.
“What it primarily exists to communicate is information about your immune system. You have a certain MHC complex which is a cluster of genes that accounts for your immune system so you’re communicating that out into the air. Perhaps the person you decide to marry has a very different cluster of genes, that is one factor in heterosexuals coupling.”
And that smell can change to reflect one’s coming down with certain diseases or illnesses.
A person’s smell, and smells in general, can be very hard to sit down and describe. Stewart says this is called the olfactory-verbal gap.
“It’s encouraging to talk to people who have a really highly developed sense of smell, wine experts and perfumers, a lot of their training consists in verbalising what their smelling… this is a sort of parlour game all of us can do to improve our sense of smell.”