Why Smell Triggers Your Memories

Welcome to the Topic “Why Smell Triggers Your Memories”

The sweet fragrant notes of lavender and freshly brewed coffee can take you on that perfect first date. Just like getting a whiff of freshly baked goods can take you to your childhood, devouring grandma's special cookies. It's uncanny how certain scents can make us so nostalgic, sometimes even bringing back memories we thought we had forgotten. It's almost as if our sense of smell is the key to our house of memories. But how does this happen? Let’s take a look.

How do smells trigger memories?

There's a structure known as the olfactory bulb, which consists of neurons that act as smell receptors. When a specific molecule binds to the receptor, an electric impulse is generated, which then goes to the brain, which is how we smell things. Now, the olfactory bulb is connected to the hippocampus and amygdala. Hippocampus is considered to be the memory center of the brain. And that is why smells can trigger memories in such a robust way. 

Although, some researchers believe that the memories might be stored in the olfactory bulb through the piriform cortex. Even though this might establish a direct link between scents and memories, popular opinion suggests memories are evoked due to the direct connection between the olfactory bulb and memory centers of the brain.

Only odors can travel directly to the hippocampus and amygdala. The other senses have to first go through the thalamus. Therefore, scents and memories have the strongest link. An experiment carried out by Dr. Rachel Herz at Brown university reinforced this statement. The experiment consisted of a two-group, the experiment group, and the control group. The experiment group was asked to smell a perfume with which they related a positive memory. Whereas on the other hand, the control group was made to smell a fragrance they had no previous recollection of. The experiment group showed more brain activity. 

How often have you smelled a particular note and been overwhelmed with joy? Smells are the most emotive of the senses. They don't just trigger memories; they trigger emotions, too, making us remember how we felt at that particular time. Similarly, a smell can also evoke certain strong negative emotions and therefore can contribute to post-traumatic stress disorder.

Sometimes, when we taste certain foods, we start getting nostalgic. We begin reminiscing about an associated memory. But it is, in fact, the smell of the food that triggers the memory rather than its taste. When we chew our food, molecules in the food travel to our nasal passage and thus elicit memories. 

Smell is the oldest of all the senses and even existed in the primal form of beings before they underwent complex evolution. That explains why we have many smell receptors and why we can distinguish between a variety of scents. You would never mistake vanilla for chocolate, would you? That is just how great the mechanism of smell is! Be it good or bad, scents indeed hold the key to our memories.