The Biology of Scent
Why do scents evoke such strong memories?
I’ve written about this before.
“How our minds and memories construct meaning is scarcely understood at all. We know the hippocampus is central to the conversion of short term memories into long term memories with repeat passage of information about a memory through the hippocampus creating a stronger and easier to recall memory. The amygdala is central to connection of emotions and sensorial input that stirs emotion with the formation and recall of memory.”Body Memory, Women’s Legacy Project
There are a few reasons that scent memories are so strong :
- The location of the olfactory bulb in the brain allows rapid communication with the amygdala (emotion) and the hippocampus (memory) and directly link with the limbic systems. The smell identification, memory, and emotion are all handled by these same parts of the brain. The thalamus directs all other senses through the brain, but scent bypasses the thalamus taking a direct route to the amygdala and hippocampus.
- Early in human life, scent is the dominant sense. The visual sense takes over by age 10.
- We can recognize kin, or people related “by blood.” Mothers can identify their biological children but not their stepchildren. Pre-adolescent children can detect their full siblings by scent but not half-siblings or step siblings. This may relate to incest avoidance.
- The piriform cortex, a part of the olfactory brain, is itself involved in the process of saving long term memories; the mechanism, however, it only works in when other brain areas tell it to create a long-term memory.
Finding mates who have a different histocompatability complex (which is related to the immune system) produces healthier offspring who have wider range of immunity. Attraction is stronger between significantly difference. Histocompatability dissimilarity correlates with partnership, sexuality and enhances the desire to procreate.
The Use of Scent
Huge amounts of research have been done related to perfumery over the centuries. We can increase pleasant perception and sexual attraction through the use of scents. Many classic perfumes contain musk which is extracted from animals who have been tortured or killed in the extraction process. Yuckola, right?
To find cruelty free evaluations you might want to start here with this Cruelty Free Kitty article.
More than simple body perfumes, a whole new area of olfactory branding exists in which corporate entities such as hotels and running shoes use scent to create a specific experiences.
How to Include Scent in History
Scents are primal and influential conveyors of information, so shouldn’t we try to include scent in the histories we create? If so, how should it be included?
I’m brainstorming here, so bare with me.
- Include scent descriptions in your writing. Use exact descriptions that might take some research, lilacs and lily-of-the-valley are quite distinct. Vanilla is not like cinnamon. The smell of bread and cake are discernible from each other. Use vivid, accurate description.
- Want to recreate the aroma of your Grandma’s Kitchen. Make her recipes. Use the spices she used. Was it a combination of Pine Sol scrubbed wooden floors and freshly baked apple pie?
- Go to a store and test different product scents. Figure out if your uncle wore Old Spice or Aqua Velva? Was the soap Irish Spring or Ivory?
- Did the garden have honeysuckle or sweet pea growing on the fence?
- The morning you remember — was it a combination of cinnamon-rich snicker-doodles, freshly washed linen, and a vanilla candle?
- Have you ever lived in the country? Pig poop smells different from chicken poop.
- Swamps smell different from pine forests.
- The hot scent of ironed fabric is nothing like dry cleaning.
I would love to hear how you might include scent in your history or writing?