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.
March 2016, BBC News
Nature Neuroscience, May 2016
March 2016, BBC News