(On my way back to Chicago for another meeting.) Sit quietly, close your eyes, and recall the scent of a lemon … soy sauce … pepper … gasoline … a baked apple. Inhale through your nose as you remember these smells. I find this entertaining, and I can get quite precise about it. For example, I can choose whether to remember a bitter lemon smell (with some of the white pith), or the pure scent of the inside of the fruit.
It appears that memories of smells decay more slowly than other sensory memories. This is a bit surprising, because “each olfactory neuron in the epithelium only survives for about 60 days, to be replaced by a new cell.” Dr. Maturin in one of the Patrick O’Brien novels notices the power of smells to restore memories and hypothesizes that it’s because we don’t have many words for scents. He thinks that because we translate our visual and auditory experiences into language, we tend to forget them, whereas we retain our olfactory sensations in their raw form.
When people (like O’Brien and Proust) write about memory and smell, they usually describe the power of real scents to evoke lost memories. The reverse is interesting, too: the power of deliberate recollection to conjure up imaginary smells.