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You walk past a bakery, or open an old cupboard, and there it is. Cinnamon, warm bread, maybe a hint of floor polish. Suddenly you’re seven years old, sitting at your grandmother’s kitchen table, swinging your legs while something bakes in the oven.
You haven’t thought about that afternoon in decades. You might not have been able to recall it if someone had asked you directly. But a single smell brought it back in an instant, with all its feeling intact.
Racing the senses
Swedish researchers Johan Willander and Maria Larsson at Stockholm University wanted to know whether memories triggered by smell are actually different from those triggered by other cues. To find out, they needed a fair comparison.
In a 2006 study published in Psychonomic Bulletin & Review, they recruited 93 adults aged 65 to 80. Each person was given one type of cue. Some got words, such as “tar” or “cinnamon.” Others saw pictures of the same things. A third group smelled the actual odors.
For each cue, participants described any personal memory that came to mind. They then rated the memory for qualities like vividness and emotion, and said roughly how old they had been when it happened.
The childhood door
For people given words and pictures, most memories came from the second decade of life, between ages 11 and 20. That fits a well-known pattern. When older adults recall their lives, memories tend to cluster in adolescence and early adulthood, a period psychologists call the reminiscence bump.
Smells broke that pattern. Most odor-triggered memories came from the first decade of life, before age 10.
The odor memories also felt different. People reported a stronger sense of being transported back in time, as if they were reliving the moment rather than just recalling it. And these memories were ones they’d thought about less often than the memories triggered by words and pictures.
A shortcut into the brain
One reason may lie in how smell is wired. Most sensory information, from sight, sound and touch, passes through a relay station called the thalamus before reaching the brain’s outer layers.
Smell is different. Signals from the nose travel to the olfactory bulb and then go almost directly to brain regions involved in emotion and memory, including the amygdala and areas closely linked to the hippocampus. Brain imaging studies have found that odor-cued memories produce stronger activity in the amygdala and hippocampal regions than picture-cued ones.
That close connection may explain why smell memories feel so emotional and so immediate. A smell doesn’t need to be described or interpreted before it reaches the brain’s memory systems.
Why childhood?
The early timing is still not fully explained. One idea is that smell is one of the first senses we use to learn about the world. Babies can recognize their mother by smell, and young children explore their environment with their noses long before they have much language.
Many childhood memories may therefore be tied more closely to smells than to words. Later in life, as language becomes our main way of organizing experience, memories are more likely to be stored and retrieved through words and images.
There’s also the matter of rarity. Many childhood smells, like a particular soap, a grandparent’s pipe tobacco or a long-gone school’s cleaning fluid, simply disappear from our lives. When one turns up decades later, it may connect to a memory that hasn’t been disturbed in years. Larsson and colleagues have summed up odor-evoked memories as typically old, vivid, emotional and rare.
Some caveats
The study had limits. All the participants were older Swedish adults, and the 20 odors were presented in a lab, not encountered naturally in daily life. A smell in a supermarket aisle may work differently from one in a small vial.
Smells also didn’t produce more memories than words or pictures. They produced older ones that felt more vivid. And the study compared smell only with words and pictures. Other research has compared it with sounds, with mixed results.
The original “Proustian moment”
The idea isn’t new. In his novel In Search of Lost Time, French writer Marcel Proust described a narrator tasting a madeleine dipped in tea and being flooded with memories of childhood Sunday mornings with his aunt. That kind of sudden, involuntary memory is now often called a Proustian moment.
Research suggests Proust was onto something real. A familiar smell may be one of the few things that can bypass decades of later memories and take us straight back to the earliest years of our lives.
