When you step outside and experience the transition from autumn to winter, the leaves on the ground rather than the trees or an even deeper chill in the air. When you notice signals of a fast-approaching spring: little green buds on the trees, a day where you have to shrug your jacket off. The smell of old books in an antique store that takes you back to your childhood library.
When you experience these moments, you're also possibly experiencing a simultaneous feeling of being transported back in time and place.
Perhaps, childhood memories of shoveling snow or kindling a campfire resurface with vivid intensity. Sensory stimuli have the power to involuntarily trigger such memories.
Time Travel Via The Nose
Olfactory stimuli, the cues people detect through smell, are special because they activate parts of your brain that spark often acutely emotional memories.
A good way to comprehend this phenomenon, and also learn more about your memories, is to understand how anatomical pathways process olfactory stimuli. After a smell enters the nose, a neural structure called the olfactory bulb relays this odor information to the brain.
The information travels through two cerebral regions: the amygdala and the hippocampus, which deal with emotion and memory respectively. However, auditory, visual, and tactile information do not take this route to the brain, which means information from these senses is less likely to induce feelings of "being taken back" or revisiting a past emotional state.
Increased Temporal Lobe Activity
As we learn more about what happens when smell stimulates memory, it becomes clearer that the resulting recollections are likely to be emotionally charged. Odor-evoked memories increase temporal lobe activity which has been linked with positive memory processing, thus creating more pleasant experiences than memories brought on by visual cues.
But, people living with PTSD may experience certain smells as potent triggers that can, without warning, shuttle them back to a moment of trauma. What might your recollection of certain odors tell you about your past?
Thank you to Jonathan Crystal of Indiana University for reviewing this episode's script!
Sources And Further Reading:
- Lewis, Jordan Gaines. "Smells Ring Bells: How Smell Triggers Memories and Emotions." Psychology Today. January 12, 2015. Accessed October 5, 2017.
- Riggio, Ronald E. "Why Certain Smells Trigger Positive Memories." Psychology Today. May 1, 2012. Accessed October 5, 2017.