In In Search of Lost Time, Marcel Proust dips a madeleine into a cup of tea, and his whole childhood in Combray comes back. Since then, “the Proust effect” has become the familiar name for a smell that brings a whole stretch of life back with it.
Almost everyone has had this happen, so the question worth asking is not whether it exists but how large it is. Compared with a photograph or a word, how are memories called up by smell different, and by how much?
Five letters and a test
Psychologists gather what people believe about smell-evoked memories into five letters, LOVER: Limbic (passing through the brain’s emotional regions), Old, Vivid, Emotional and Rare (seldom recalled). In 2019 a review pooled 13 studies, comprising 14 experiments, that set smell against words and pictures, and tested the letters one at a time.
| Property | Smell compared with words or pictures | Support |
|---|---|---|
| Old, from the first ten years of life | 51% against 22% | Strong |
| Seldom recalled | d = 0.52 | Yes, but few studies |
| Emotional | d = 0.47 | Yes |
| Sense of being carried back | d = 0.47 | Yes |
| More positive | d = 0.35 | Yes |
| Vivid | d = 0.10 | Very small, not robust |
| Brings back a memory at all | 63% against 76% | Reversed: smell does worse |
The d is an effect size: around 0.2 is small, 0.5 medium, 0.8 large. None of the properties of smell-evoked memory reaches the large range. The emotional advantage is real, but medium-sized. One study of 93 older adults found no clear emotional advantage at all, while confirming that memories called up by smell were older.
A key that fits few locks
The last row of the table is the one least often mentioned. Give people a smell and ask what it reminds them of, and they find a memory 63% of the time; give them a word or a picture and the figure is 76%. As a general cue, smell does worse.
But when it does open a door, it opens it further. In a 2002 experiment, people recounted a memory and were then cued again with the very smell tied to it, with the name of the smell, or with a picture. The matching smell drew out far more new detail than the name or the picture. An unrelated smell made people say less. In other words, it is not that any smell wakes memory up; it has to be the right one.
Why childhood
Memories called up by smell cluster in the first ten years of life, while those called up by words or pictures cluster at roughly 11 to 20. When people were also told the name of the smell, they recalled more, but the childhood peak disappeared. One reading the data support is that these associations form before language takes over the way we remember.
A survey of 647 people published in 2026 found that 73% of earliest smell memories came from events repeated more than five times. A “Proust memory” is therefore more often a memory of a familiar setting, such as a family meal or a relative’s kitchen, than of one particular day.
The “limbic” part is thinner than people think
The L in LOVER rests on very little data: the brain-imaging study cited most often had 5 participants. The anatomy is right: a smell signal reaches the amygdala after only two synapses, without passing through the thalamus. But short is not the same as fast. Recordings from single neurons in the human brain show the amygdala recognising a smell only about 50 milliseconds after the piriform cortex, while the hippocampus takes about 1.1 seconds.
What this means when you choose a scent
- A new scent cannot bring back an old memory. A smell can only open memories it was attached to before.
- The smells tied to memory are usually smells met many times in the same setting. If you want a scent to become the scent of a period of your life, use it repeatedly during that period.
- Two people smelling the same bottle will be carried back to two different places, because liking or disliking a smell is mostly about the person smelling it.
The underlying evidence is in our research section: Results: orbitofrontal cortex, hippocampus and odour-evoked memory and Discussion and conclusions.
Sources
- Hackländer, Janssen and Bermeitinger (2019). An in-depth review of the methods, findings, and theories associated with odor-evoked autobiographical memory. Psychonomic Bulletin & Review 26(2), 401–429.
- Chu and Downes (2002). Proust nose best: Odors are better cues of autobiographical memory. Memory & Cognition 30(4), 511–518.
- Willander and Larsson (2006). Smell your way back to childhood: Autobiographical odor memory. Psychonomic Bulletin & Review 13(2), 240–244. (abstract read)
- Larsson, Willander, Karlsson and Arshamian (2014). Olfactory LOVER: behavioral and neural correlates of autobiographical odor memory. Frontiers in Psychology 5, 312.
- Dejou et al. (2026). Positive early-life olfactory memory is rooted in the olfactory bulb and triggers large-scale changes beyond the olfactory system. PLOS Biology 24(7), e3003845.
- Kehl et al. (2024). Single-neuron representations of odours in the human brain. Nature 634, 626–634.