Why does scent evoke strong memories?
By Sadaf Ahsan
When I picture my mom, I picture her in her garden, plucking dead roots, planting vegetables, admiring her marigolds and tulips. I see her hands stained with dirt, pricked by thorns.
When I picture my mom, I also see her in her kitchen, grinding peppercorns, marvelling at her beautiful home-grown jalapenos, kneading rotis. I see the perspiration on her brow and her nose twitch as she takes in the nostalgic smell of her own mother’s recipes.
When I picture my mom, I see someone whose image I can instantly conjure up not just by seeing her favourite flower or cooking her most beloved dish, but from all of the smells she surrounded me with since I was a child: spice and spruce, and the sweat of her hard work.
In early 2020, I travelled across France to celebrate my 30th birthday and decided to bottle the scent that would forever remind me of my mom so I could never forget her. With a friend, I made a pit stop on the French Riviera, in Grasse, a small town considered to be the perfume capital of the world.
We visited Galimard, a renowned perfumery that was established in 1747. There, we visited a vibrant studio where it seemed that every scent imaginable was at our fingertips. Galimard’s world-class perfumers told us to choose what spoke to us, mix it all together and, with a little guidance from them, we’d have our own one-of-a-kind scent.
I labelled mine “Saroash” — my mom’s maiden name. It features notes of cardamom, peach, patchouli, sandalwood and a whole host of odd fellows. Each fragment came together to paint the picture I never want to forget: my mom, in the summer, happy. An aromatic portrait.
But how could I paint this picture just through scent? How did the association between smell and memory come to be?
To put it very simply, explains Afif Aqrabawi, who studies scent and memory, memory is a set of cells that become active from an experience. The cells can be reactivated — or recalled — when you encounter a cue that resembles or reminds you of that experience.
“Olfaction is arguably the most important sense because of the fact that it gives us everything we need to know about where there’s food, where there’s potential mates, where there’s a potential predator,” says Aqrabawi, a neuroscientist at the Massachusetts Institute of Technology. “It’s very informative, even if we don’t appreciate that informative value because we’re visual creatures.”
He says the hippocampus, which is key in this process, functions as a kind of organizer of memories. Aqrabawi suggests imagining the hippocampus as a librarian and your memories as books. The hippocampus, then, is cataloguing the books and generating an index. It’s the amygdala, meanwhile, that emotionally processes what’s happening.
By way of an illustration, he asks you to imagine that you’re walking into a bakery, and you smell fresh butter croissants. This experience activates a certain set of neurons in your brain. If this same set of cells is reactivated the next time you smell a butter croissant, that is an instance of memory recollection at work. Cues that can trigger a memory can be smell, sound or an image.
In fact, adds Aqrabawi, “You never really forget anything, even though you sometimes don’t have conscious access to it. You encode every experience in your daily life.”
Our scent memory is stronger than our visual memory thanks to the direct anatomical connection between the hippocampus and the olfactory system, which is where a smell first heads to in the brain. When it comes to other senses — like when you see, touch or hear something — that information first goes to the thalamus, before heading to the hippocampus and the amygdala.
Yvonne Chan (MSc ’98, MD ’02, PGME ’06 & ’07), an associate professor at the Temerty Faculty of Medicine’s Department of Otolaryngology Head and Neck Surgery, says her patients present with different conditions that affect their sense of smell.
“Some of my patients range from not having any smell and that not affecting them at all; whereas for others, the loss of smell is devastating. It’s very dependent on your livelihood. If you’re a chef or a sommelier, someone who needs smell for your daily living, you need to be able to smell smoke or if food has spoiled. Everyone’s different,” says Chan, who is also the otolaryngologist-in-chief at St. Michael’s Hospital, Unity Health Toronto.
She recalls having one particular patient who lost her ability to smell due to nasal polyps and chronic sinusitis. The patient began to avoid regular dinners with friends because she could no longer fully enjoy the meal. (Between 75 and 95 per cent of what we taste is believed to be rooted in our sense of smell, so the loss of this sense can greatly affect our eating habits.)
The patient eventually started isolating herself, which led to depression. She ended up in Chan’s office in tears. “Smell affects your sense of security, safety and your social life. It’s really intertwined with memory,” says Chan.
The loss of smell can come not only from chronic conditions or colds, but just as we can slowly lose our hearing as we get older, we can also slowly lose this sense, says Chan. We’ve heard more about the loss of smell since COVID-19, which attacks the olfactory system, says Chan. Countless COVID-19 patients have lost their sense of smell.
“If you don’t lose smell, you don’t really know how important it is for you. Some of my patients become truly devastated and that’s the main thing that they want back even if they can’t breathe, if they have pain or a runny nose all the time,” says Chan.
Today, when I pick up my bottle of Saroash, which has literally captured my mom in a bottle, I don’t only envision her, but I feel that sense of safety, security — and love. Scent, in other words, has the power to be so much more than what we might think. It can be a whole world of emotions. To lose our sense of smell would be to lose ourselves. •