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Lots of discoveries have been popping up on the subject of memory. UK
scientists won the Brain Prize for
showing how memories are stored in the brain, based on the “fire together,
wire together” theory.
Some recent work on how we forget
has come up that reminds us why our smell memories stay potent forever. The
idea that we forget memories after repeatedly recalling similar memories has
been around for a while, but for the first time, scientists show evidence of
active repression.
In Hidden Scents:
The Language of Smell in the Age of Approximation, the potency and tenacity
of our smell memories are discussed as an analogy to the concept of lossy data in
computer science. In the study linked above, memories that are repeatedly
accessed have a negative lasting effect of on the fidelity of similar memories.
In computer science, every time a .jpg is opened and re-saved, it loses some of
its data due to compression. This is what lossy data compression is about.
For smell memories however, where the memory is instigated by a unique
signature of aroma compounds (one that might represent your grandparents’
attic, for example), this process of retrieval and re-saving does not happen
for perhaps forty years. And then one day: You know that feeling – it’s called
the Proustian moment, after the most widely recognized description of olfactory
memory in literary fiction – it’s when you walk into a room and you’re hit,
halted in your tracks, and assaulted by your past, captured in a moment that
consumes your awareness.
“Oh my….oh…that’s…that’s my grandparents’ attic – I haven’t thought
about that in forty years.”
And you shiver, you time-traveler, re-living a most personal page in
your autobiography. Again, the reason smells can do this to us is because these
instigating signatures, these unique aroma profiles, are such a complex and
nuanced combination of molecules that the chances of your encountering them on
a regular basis can be very small. There is no opportunity to rewrite the data.
It just sits there forever, waiting.
There’s more to the story of course, like the fact that these memories
are a holistic conglomerate of spatiotemporal, physiological data about the
precise state of your body at the moment of encoding, but that’s already too
much for today.
Notes:
March 2016, BBC News
http://www.bbc.com/news/science-environment-31909935
Nature Neuroscience, May 2016
March 2016, BBC News
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