How Smells Trigger Memory
Every one of us has a memory attached to certain smells. The scent of our favorite comfort food wraps us in warmth and can make us feel better after a difficult day. Perfumes or lotions worn by the people we love can transport us to specific memories with them. And it isn’t just the memory scents can induce, but the emotions attached to the memory as well.
The Emotional Connection
When we smell something, our brain takes that sensation and has to process it so it can understand and translate the experience as a scent. But because the areas of our brain required for this processing and translation are interconnected with the areas responsible for memory and emotion, it often gets tangled together.
After our brain translates the scent into readable information in our olfactory bulbs, it moves to the amygdala and the hippocampus, where we process emotion and memory, respectively. This process is different from our other four senses. When it comes to touch, sight, sound, our brain first takes the sensory information to our thalamus which acts as a relay center, sending the information to the necessary areas of the brain. But with scent, it bypasses that process, heading straight to our emotional memory centers, intertwining our brain’s interpretation of scent with our emotions which then makes it more memorable. Taste is often intertwined with smell, which is why we have the same strong emotional connections with food.
The Olfactory Bulb
But why, then, does our sense of smell seem to trigger memories more intimately than looking at old pictures? The answer may have something to do with a more recent discovery by scientists concerning our olfactory bulb.
They discovered that the memories we have related to a smell may be saved in the bulb itself, thanks to a structure known as the piriform cortex. Within this part of the brain, there is a higher-level structure, the orbitofrontal cortex, where we make judgments about stimuli based on our sensory input. In the study, they determined that the piriform cortex is able to act as an archive of sorts for memories, but it needs the orbitofrontal cortex to direct which information gets stored and which information is discarded.
It seems that evolution played an essential role in why smell goes directly to the amygdala and hippocampus, along with why the piriform cortex stores scents in our long-term memory banks. Being able to recognize chemical compounds that could kill us was extremely important in our primitive days. So was recognizing when food was rancid or avoiding animals or tribes that posed a threat to us. Being tied to emotions helps us remember scents as dangerous, or a trusted food source, or a safe place to rest.
In fact, because it’s tied to our emotional responses, just with any other memory, the details can get muddled. Scent raises a strong emotional reaction within us, that we tend to trust the memory entirely, but research shows that while we remember the feeling a scent evokes, the actual memory can change over time.
The fact that we have over 1,000 types of scent receptors is an indication of how important our sense of smell is to our brain. It’s linked to our emotions and memories in a direct pathway that is unlike any of our remaining four senses. Whenever we’re pulled into a memory based on a specific scent, remember it’s the olfactory bulb and the unique way our brain processes scent that got us there.