I've forgotten so much about my childhood…. and then there's the part I simply never remembered. I'd like to drop a little physiological psychology mumbo-jumbo on you (which I am not academically qualified in the least to sling around, for the record) in an effort to distinguish between these two types of memory deletions.  

Let's say that a sensory impression either "lands" in the mind or doesn't—it either slips from the immediacy of now into the short-term memory, and then into the long-term memory, or it just slips away. This happens to you tens of thousands of times per day. Do you remember the precise feeling of your neck's skin as your fingernails absently scratched it four hours ago? 

Didn't think so. Now let's say there's something you remembered for a time, like the way your toe hurt when you stubbed it against the edge of the table nine hours ago. That sensation eventually disappeared, and now you probably don't even remember which toe you stubbed. 

Now let's move on to the juicier sensations. Do you remember the feeling of being yelled at by your neighbor six weeks ago? Do you even remember being yelled at? It's a toss-up, because

there is a psychic function that determines whether a sensation sticks in our memory or not, and if it doesn't stick, then it has been subject to a passive form of deletion. 

You simply didn't remember it, even if it made a strong impression on you at the time. It doesn't become part of your narrative of yourself, so it remains unconnected to who you think you are. Though it will likely shape who you are by affecting your future choices, the things you gravitate toward or avoid, etc. 

And then there's the stuff you actively forget, either through some perfectly innocent process of neurochemical attrition, or through active suppression. They say that what you suppress comes back to you in spades, and they're probably right. But what about the stuff that, like computer files during a routine backup, got screwed up or transformed into something unreadable? 

Those things happen in the human mind, too. So I regularly ask myself, when I think of the deleted data in my personal files, what simply didn't make it into long-term storage, what I've tried to delete by putting into the trash, and what has simply become unreadable by the current operating system of my mind? 

And is there any difference in the way each set of deleted data behaves within me, shaping who I am and who I may be? 

1. THINGS I DON'T / CAN'T / WON'T REMEMBER
2. DID SOMETHING HAPPEN TO ME?
3. THE WITNESS