I suspect we have a variable number of supplemental threads of execution serving the primary one we live on.
Recalling distant memories asynchronously after struggling to remember anything about it sometimes feels very much like another person interrupting and delivering the information once it's found.
Memory is a weird beast with many variables. A few things I know:
1. It's state dependent.
Example: I had a tortured first pregnancy and the birth was awful. For years, I couldn't clearly remember it.
Then I had a lengthy medical crisis that involved constant, excruciating pain. Suddenly, I could clearly remember the birth of my first child.
2. It's context dependent.
For example, people frequently fail to identify individuals they know if they run into them someplace they wouldn't expect to see them. They may realize they know the person, but just can't place them. (I have experienced this.)
This is also the mechanism behind going to do a thing, forgetting what it is, remembering when you return to where you were.
3. Emotion is a form of memory.
People with strong affect can make snap decisions based on "gut feeling." People with low affect cannot make snap decisions. They lack the file that sums up all their pertinent experiences as either "I have good feeling about this" or "I have a bad feeling about this."
4. "Muscle memory"
Some people think better while active. This is your stereotypical Pacer.
If you keep a dream journal, it's easier to remember dreams if you keep a pen and notebook on the nightstand and make notes without getting up at all. It's best to stay in bed and try to not leave your sleep position. Dreams can sometimes be retrieved by returning to whatever position you were laying in while dreaming.
5. Some people think in pictures. Some in words. This effects memory storage.
For most people, conscious recall of memory corresponds to learning to speak. It apparently heels people catalog their memories so the files are accessible.
I have a son who thinks in pictures. At some point, it became clear he could access pre-verbal memories, but it was like listening to someone translate a thing into English.
We actually went through a period where he waited until everyone else was asleep, then he would share his memories with me. Translating them to words from pictures helped him more readily access them.
There's no doubt tons more stuff to know about memory. This is very off the cuff.
Recalling distant memories asynchronously after struggling to remember anything about it sometimes feels very much like another person interrupting and delivering the information once it's found.