First, we should define what a memory is. Memories are a collection of thoughts and sensations pertaining to an earlier time. They are composed of all aspects of existence at a given moment, both the external (sensory inputs) and the internal (thoughtspace i.e. emotions, internal monologue, recalled memories, daydreams, etc.). Existence is the collision of the external and the internal. Some moments of our existence are not particularly noteworthy. But others are super sweet, either very enjoyable, very powerful, or maybe very meaningful for the subsequent moments of your life, i.e. there are things worth remembering. Because this is a universal situation, there are many ways to freeze moments, or a series of moments, and save them for later.
It’s probably easiest to think of the various forms of memory encapsulation in terms of what sense they pertain to. Vision. You could take a picture. Since the current iteration of humanity tends to be ocu-centric, pictures are appealing memory aids, but pictures capture only an instant. If a moment is an infinitesimally small unit of time, events like say, a wedding, last an infinite number of moments (or longer, depending on the officiant). That’s a lot of pictures, and many are just sitting around, staring off into space, or other moments that could slip into the abyss without anyone minding very much. Hearing. Make an audio recording, but then you would have to listen through the whole thing, and many parts would probably be weird or boring, like eating and sleeping, respectively. Same problem with video. Maybe you could even write a story, but trying to wrap words around an experience is fickle at best. Taste would be interesting, but it would be made up mostly of eating and drinking and things that can’t be spoken of in polite company. Touch. Same problem.
This brings us to scent, which truly kicks the shit out of all other methods. Wouldn’t it be great if you could have a moment/memory catching device with a filter on it so that it only captured the most intense and meaningful pieces, and let all the others fall softly out of focus? Turns out, it’s a built-in feature for your nose.
Scent and memory are tied together in a variety of weird ways, but there are two factors that are really important for the sake of this discussion:
- When you experience a new scent, the state of your existence at that moment gets tied to that scent as a sort of scent/memory .
- The more intense your emotional state, the closer the scent and the memory get tied together.
So scent memory has a built-in emotional-intensity threshold filter (probably more similar to the hysteresis threshold of a Schmitt trigger than a simple comparator) that only records during the happiest, saddest, most exciting, anxiety-inducing and joyous moments. Basically, all the best parts.
And the strength with which scent memories form is primarily a function of two things: originality of scent and the absolute value of emotional intensity. From that we conclude that a good way to link a scent and a memory is to present a new fragrance, at a time of intense emotional states, and then let scent be the medium for storing all the most intense emotional moments. Don’t smell that scent again too often, only when you really want to recall the memory.