In deference to Memorial Day this past Monday, we dedicate the next few weeks to investigating the effects of memory. Let us start with three fundamental certainties of memory.

Memory is both personal and shared.

Memorial Day exists as a collective reminder to remember, even if the memory isn’t a personal one. Our culture, like many others, honors those who dedicate their lives to the greater good. When a soldier falls, they are remembered by their loved ones, and those who knew them. Yet for the average citizen, there is no personal memory to hold. Hence the creation of a national holiday.

Memory is incredibly important and influential while also and fragile and fleeting.

Our complex human brain is built on memory, yet memory itself is not concrete. Each of the myriad cultures existing in our world ride precariously on the back of memories passed down from our forbearers. In just one generation, a culture can change drastically or disappear all together, all contingent upon what history is shared with the next generation.

Cultural memory is a carefully constructed understanding which is taught to future generations in an effort to pass on values, traditions and history, through texts, oral traditions, rites, art and other symbols.

Memory in the brain is formed, stored, and retrieved in different ways.

Through each new experience we gain a new memory. The question is, how much detail do we keep? There is a small percent of people who possess an eidetic memory, or extraordinarily accurate visual recall. It is tiny, only 2-15% of preadolescents and almost no evidence of the skill lasting into adulthood. Most of our experiences are instead stored in the brain as sensory, short term or long term memory. From these stages there is also two types, explicit (what we are consciously aware of) or implicit (unconscious influences). This lack of eidetic memory is why a person may recall the gist of a conversation they had, but not the name or face of the person they spoke with, or why they may have a feeling they don’t like a certain restaurant without remembering the person sharing a poor review.