Have you ever experienced a strong feeling of nostalgia when you walk into a bakery you haven’t been to in years? Or noticed how even a whiff of your favorite childhood food can instantly flood your brain with recollections of the past? The reason behind it all is the process of how your memories are encoded through your chemical sense of smell.
Our brain plays a huge role in what we sense: our vision, hearing, touch, taste, and smell. Yet, the process of smell is the only one out of the five that has an anatomical connection to emotion. What is the science behind this, and what role do smells have on our memories and emotions? Read to find out!
Behind The Process - Olfaction
Firstly, how do we detect smells? The process, scientifically referred to as olfaction, depends on a series of connections between the cells in our nostrils and parts of our brain.
When substances have a smell, they contain chemicals whose molecules diffuse into the air. Some of these molecules travel into our noses, where they will land in the mucous membranes of our nostrils. In these membranes, there are various cells that respond to these chemical signals, specifically called olfactory receptor cells, that can detect the different smells we sense. The information processed by these response cells will be collected in the olfactory bulb, which will alert the brain of these signals.
However, instead of directly going to the brain like other senses such as taste, vision, hearing, and touch, the information first goes to the amygdala, which is a part of the brain’s limbic system that controls emotion, then to the brain’s hippocampus, which controls memories.
What Does This Mean?
As a result, the smells we detect become encoded into our memories along with the emotions associated with them in that moment. Therefore, when we encounter the same smell again, we experience a feeling of nostalgia, and remember past associations we had with certain smells.
Because smells have such powerful access to our emotions and memories, they can bring back memories of things that have been long forgotten. They are often considered as a way for us to connect with the world around us and create experiences that we will remember throughout our lifetime.
But what happens if you lose your sense of smell? We’ve all experienced that terrible feeling of having a stuffy nose, but what about people who have a more permanent absence of smell?
The disorder where your sense of smell is lost is called anosmia, and those who suffer from it report feelings of isolation and experience less intense emotions. Being unable to smell sometimes may lead to psychological orders such as depression due to being unable to experience and maintain relationships the same way. Additionally, it can lead to memory loss, as it can be an indicator for Alzheimer’s disease.
Therefore, you shouldn't take your sense of smell for granted. Take time to stop and smell the roses. But of course, stay safe and remember to follow the COVID-19 health guidelines!
References:
Ed.D., Weseley Allyson, and McEntarffer Robert Ph.D. Barron’s AP Psychology, 8th Edition: With Bonus Online Tests. 8th ed., Barron’s Educational Series, 2018.
“Psychology and Smell – Fifth Sense.” Fifth Sense, www.fifthsense.org.uk/psychology-and-smell.
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