Sometimes a smell suddenly brings back an old memory, like the smell of your grandmother's house. This is called the Proust effect. It is named after a French writer.

Scientists found that memories brought back by smells are often older than memories brought back by words. Many come from before age ten. Smell memories also feel more emotional. A smell can work like a time machine.

Have you ever smelled something and suddenly remembered a scene from childhood? This is called the Proust effect, after the French novelist Marcel Proust, whose character remembered his childhood after tasting a madeleine dipped in tea. In a 2000 study, older adults described memories triggered by either words or smells.

Word-cued memories mostly came from their teens and twenties, but smell-cued memories peaked at around six to ten years old. A 2002 study also found that memories triggered by smells were more emotional than those triggered by pictures, though they were not always more accurate. One explanation is that smell signals travel to brain areas linked to emotion and memory more directly than other senses.

The Proust effect takes its name from Marcel Proust, whose narrator is flooded with childhood memories after tasting a madeleine soaked in tea. Psychologists have tested whether smells really have a special power over memory, and the evidence points to two distinctive features.

First, odor-evoked memories tend to be older. In a 2000 study, older adults recalled life events in response to either words or odors. Word-cued memories clustered in adolescence and early adulthood, the well-known "reminiscence bump", whereas odor-cued memories peaked at roughly six to ten years of age. A 2006 Swedish study replicated this shift, finding odor memories concentrated in the first decade of life.

Second, such memories are especially emotional. A 2002 experiment comparing the smell and the photograph of the same everyday object found that odors produced more emotional memories and a stronger sense of being brought back in time, although they were not consistently more detailed or vivid. A common explanation is anatomical: olfactory signals reach regions near the amygdala and hippocampus without passing through the thalamus. However, direct causal evidence for this account is limited, and most studies involved only dozens of participants.