I've also said that as we learn more and more, we may lose earlier memories or change those memories to fit in with the newer information that is arriving!
I've been known to say that as we age, of course we may alter or forget stuff - because our brains have years and years of memories to sort through, filter, and recall...
And so it did not surprise me at all to see this recent research which has shown that:
Recalling a particular memory can cause us to forget another, similar memory - and neuroscientists have now watched this process happen using brain scans.
I like to think of the brain like a file cabinet drawer or shelf, or even a folder such as you might have on your computer. In your file cabinet drawer you have manila folders - usually the 3 cut ones with the tabs on top which you label for certain papers. If you have a lot of folders that are for different but related material, you might have these within a larger folder - the kind with hooks on the side that you can slide backwards and forwards in the drawer. How many of the larger sliding folders and how many of the smaller manila folders that you have is really up to you and your particular filing system.
But. And it's a big but. The drawer is only so many feet, if not inches, long. There is a limit to the number of larger and smaller folders that you can push into that drawer before it gets jammed. What you do at that point is sort of what your brain does. It has to make space somehow for newer material. You can move a whole batch of those folders to another drawer. You can look through them and say I don't need these anymore and either shred them or toss them.
That's what we do in our brains. Maybe the stuff is never lost but it's been put in a drawer that is seldom used because you just don't need those memories or that information anymore. Maybe it's still there and under some degree of hypnosis or thinking or whenever you can bring it back but if it's really now irrelevant to your life - why not just forget it.....