What’s your earliest childhood memory? And your most bitter-sweet one? Can you rekindle your great and joyful past events clearly? Maybe you can answer those questions easily, but that says little about your ability to recall facts and events as they really happened.
Apparently, a single long-term memory did not even exist as an entity. Our mind is not a library where a pile of books rests waiting for being loaned at will. Each life event is broken into several pieces that are stored in different places of our brain, sometimes redundantly. When we try to recall a memory, a process of reconstruction takes place.
It often happens that we find ourselves unable to conjure up a particular event. Probably, it would come later, unexpectedly. Then, if it is still relevant, we will make an unconscious effort to store it again, reinforcing the chances of a future successful retrieval. But memories are volatile, shifting and unstable.
The process of reconstruction can add irrelevant and misleading information to the original event, making new pictures of our past reality each time we trigger and recall them. Depending on the situation in which we try to remember something, our brain can take a wrong path and end up with a wrong set of pieces to build a past experience.
I would not go so far as to say that we can barely trust our brain storage system, but next time you want to remember something, think about the possibility of taking your memories with a pinch of salt and, if you have your smartphone, take a picture. It is worth a thousand memories.