Our waiter set down a warm bowl in front of me. The aroma and steam rising from the bowl grabbed me by the nostrils and sent me on a bullet train 40 years back to my grandma’s kitchen in Guam. I closed my eyes as the sweet perfume of coconut cream brought back the feeling of the cool, bare cement floor on my six-year-old feet and the sound of Grandma’s bamboo spoon tapping the side of her old aluminum saucepan. The magical fragrance wafting from this tiny bowl of coconut and black rice porridge was like a time machine.
Smell, also called olfaction, is our most ancient sense. The acute sense of smell in the hagfish, which is one of our most primitive vertebrate ancestors, helps it mate and find food and ancestral breeding grounds. The hagfish is a limbless, eel-like marine animal that still roams the ocean today with a single nostril, rudimentary eyes and a frightening circle of toothlike raspers in its jawless mouth.
Even after millions of years, this ancient connection between the area of the brain used for smelling (the primary olfactory cortex) and the brain’s memory centers, remains strong and relatively unchanged. It’s also how even the tiniest whiff of something can thrust a person down memory lane.
The origins of this olfactory pathway suggest deep connections between smell-memory and the strong bonds we form with people in our lives. This association is especially relevant when thinking about how a loss of smell, which is a common symptom of COVID-19, is often accompanied by depression symptoms. Could the loss of the sense of smell, and thus the inability to make lasting memories, be the reason behind COVID-19 depression symptoms? If so, the answer could lie within this ancient pathway.
In my grandma’s old aluminum pot, black rice bubbled in rich coconut cream for hours. It was a velvety midnight purple color that perfectly matched the warm, blanket-like smell of coconut comfort. With every spoonful, grandma’s coconut porridge wrapped itself around me, like her safe embrace. More than 40 years’ worth of new experiences buried the memory of Grandma’s magic porridge, but in this restaurant, at this moment, I stood on those cool cement floors in a far and locked-away corner of my mind reopened by a simple scent.
Lisa Ganser, PhD, is a health communications specialist for the Alaka’ina Foundation Family of Companies in Atlanta. She was formerly a vertebrate physiologist for Kennesaw State University in Kennesaw, Georgia, where she taught human physiology, comparative vertebrate anatomy and ecophysiology courses. Ganser enjoys working with the public—especially indigenous populations and tribal communities—and finding new ways to help her community through science.