You’re walking through a hardware store one day
when all of a sudden you catch a whiff,
something you haven’t smelled in years.
Somehow the scent of glue immediately takes you back to your kindergarten classroom
and you spend the next couple of minutes wondering
what happened to that kid who used to eat all that paste.
You just experience what’s known as odor-evoked autobiographical memory ,
to put it simply,
a smell made you remember something from your past,
and it happened because of the way smells and memories
are hardwired into your brain.
Lots of different cues like sights or sounds
or even someone describing something
or telling a story unrelated to your story,
they can trigger memories.
The memories linked to smells are often stronger and more vivid,
and studies have shown that
they also tend to be memories of your early life,
often before you were 10 years old.
Which is weird,
because adults usually experience what’s known as a reminiscence bump
when they don’t remember much from before their adolescence.
But smells are really good at bringing those memories back.
These memories tend to be more perceptual rather than conceptual,
so you remember a particular sensation
rather than a bunch of facts about something that happened.
And researchers have come up with some theories
why memories triggered by smells are so odd.
There’s a big difference between the way your body handles sight,
sound, taste and touch,
and the way it processes smells.
Those other senses are all routed through the thalamus,
the part of your brain that sends them off into
the appropriate processing centers.
But smells bypass all that.
Once they’re detected by receptors in your nose,
the signal heads straight to your olfactory bulb,
the smell-analyzing region in your brain,
and that area happens to
be connected to the amygdala and the hippocampus
which are parts of the brain that help handle memory and emotion.
So it’s possible that when you smelled that glue in kindergarten,
the signal got tangled up with
memories of building blocks and apple juice.
And when you smelled it again,
later you remembered not just the glue,
but also some of the associated memories,
like that weird kid who ate the paste.
In 2013 a group of European psychologists tested this whole phenomenon
using functional magnetic resonance imaging.
First they presented subjects with 20 different strong specific odors,
like garlic, whiskey and leather,
then for each person they identified the two
that elicited the oldest positive memories,
then it was time to scan their brains.
Each subject was presented with their two experimental smells
plus two generic control smells, flowers and citrus.
They also shown some verbal cues
which were just the names of the smells projected onto a screen.
The researchers found that both types of triggers
tended to activate the regions of the brain associated with memory.
But while the verbal cues lit up parts of the brain
that were responsible for processing smells,
the smells themselves were more strongly connected to emotional processing centers.
Some of the participants associated the smells with memories
from before they were 10,
while others remembered things from when they were between 10 and 20.
Depending on which time frame the memories fell into,
their brains tended to use different regions to recall them.
The earlier memory is lit up the orbitofrontal cortex
which is connected to perception,
The later ones on the other hand tended to
activate the left inferior frontal gyrus
which handles more conceptual memories.
So can you use your nose’s superpowers
to help you remember things for your next big exam?
Smells tend to evoke early perceptive memories of events,
So the scent of glue might make you remember
playing with construction paper in kindergarten,
but your smell memory will not help you memorize Maxwell’s equations.
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