Many people have experienced odors that tap into emotionally charged memories. One whiff of rubbing alcohol can bring back memories of a hospital stay; the aroma of baking cookies can transport the ôsmellerö back to childhood where Mama was baking cookies in the kitchen. Marcel Proust writes in SwannÆs Way about taking one taste of a Madeleine dipped in tea, and the taste and smell of that bite taking him back to when he used to have tea with his aunt, and she would dip a Madeleine in tea for him.
This curious phenomenon has its roots in the olfactory system. Although sensory neurons in the epithelium survive for only about 60 days, some smells can trigger memories of events that take place many years earlier. This apparent paradox is explained by the fact that neurons in the epithelium generally have successors that take on the role of the old neuron as it dies (Ito 2000). This has been explained by saying that ômemories survive because the axons of neurons that express the same receptor always go to the same placeö (Ito 2000).
Researchers have pinpointed conditions that facilitate the relationship between memory and cognition. If the smell is present during the original experience and also when you are trying to remember, smell can aid memory; this works best if the smell is unfamiliar, but if it is familiar, it works better if it is ôunusual in the contextö (Herz 1997). Interestingly, the area of the brain where emotions are processed evolved directly from the brainÆs primitive smell structures (Kruszelnicki 2003). The connection between smells and odors also creates a connection between the left and right sides of the brain:
When you're making a memory, you mainly store it in the left dorsal prefrontal cortex. But when you try to retrieve that memory, that happens in the right prefrontal cortex. When you try to work out what an odour or smell is, you do that processing in the right side of the brain (Krusz...