MY memory IS very selective. It is AMAZING! I can't even tell you everything I had for breakfast yesterday. I won't even TRY to remember more than 50 digits of PI. Even when I was like 16, I hadn't committed the color code to memory.(You know, black, brown, red, orange,yellow,green,blue, violet, gray, white, gold,silver) I have to logically recall ohms formulas. YET, I learned things when I was 3 or so that I could tap into NOW(over 40 years later). It took me over 20 years before I STARTED to forget some C. I remember various diseases and the cures, etc...
Oh well, lets just say my memory is selective even though sometimes it SEEMS like I know everything.
I WISH I never forgot still. I actually went through a french book and learned it ALL one day. The next day, I forgot almost everything. It was almost like drew barrymore's character in "50 first dates"! Oh well, it was a THICK book! Over 3000 words. That is a lot to learn in one day.