By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF and science writer for Lumos Labs.
Memories are vital to our ability to function on even the most basic of levels. Our respective “realities” are in fact a large part due to the constantly shifting kaleidoscope of our remembrances. Here we will touch briefly on the difference between short-term/working memory and long-term memory as well as how the two filter and add meaning to our worlds.
What if we could remember everything we experienced? As enticing as
it sounds, our finite brains would quickly find themselves overwhelmed with the random details of yesterday’s weather forecast alongside the nutritional information off of last month’s box of raisin bran.
Thankfully, the vast majority of our memories are fleeting mental wisps lasting only seconds to minutes. These temporary impressions make up what is called short-term or working memory.
Working memory can be thought of as a staging area where the mind takes meaning from such items as:
- Specific immediate memories of very recent sensory input (IE the sour smell of expired milk).
- The temporary recollection of details from long-term memories (IE what happened the last time you drank sour milk).
- Conclusions and ideas made in the past (Sour milk is bad).
Notice how working memory can temporarily pull details from long-term memory for short-term use. Although
constantly changing and ephemeral itself, working memory is vital to our ability to make decisions and take action over time (such as our pouring that sour milk down the drain). For a brilliant and more in-depth description of working memory read Elizabeth Buchen’s “Working Memory: What it is and how it works”.
When an experience or piece of information sticks and doesn’t evaporate with short-term memory, it is said to have entered into the realm of long-term memory. This journey is called consolidation and takes place after prolonged exposure to a piece of information or experience. The longer the exposure, the better the consolidation, the more robust the related memories will be.
Long-term memories can store much larger quantities of information than working memory and for much longer periods of time (often as much as a lifetime). These resilient long-term recollections are made up of both consciously learned facts, such as “Madrid is the capital of Spain” and subconsciously learned knowledge, such as the ability to balance and ride a bike.
We derive meaning and the ability to act via the synergistic relationship between long-term 
and working memory. Working memory combines elements from our long-term stores with immediate sensory information in order to generate ideas and plans of action. For example, remembering that the taste of peanut butter is pleasant as we toast toast, might just have us use our memorized skill of unscrewing a jar in order to manifest the pleasurable experience of peanut butter on toast. Which is just one more potentially delicious result of a fit and active mind.
