do some memories push out room for others?

I found myself this week watching old episodes of The Simpsons - from the 90s. I haven’t watched new episodes of the show for a really long time, and I don’t think I’ve even seen these classic episodes since the early 2000s.

And yet I found myself remembering nearly every line of (admittedly great) dialogue. This got me thinking: if I hadn’t remembered these shows (or lyrics to old songs or anything else like that) would I have more “room” in my brain to remember other important things?

Or is the brain more like a muscle, where the more you work it (by remembering and recalling) the stronger it gets, and therefore the capacity increases?

As for me, well, I often have to relearn something I’ve known but set aside for years. Some things I relearn quickly, others more slowly. I do believe I forget a lot of stuff, but I’m always learning new stuff. Not sure if failing to learn new stuff would mean I hang onto the old memories though…

Kids are a bit different: I was amazed at my kid’s developing mind as he grew up. We had shared memories that we would often bring up, up to about the time he turned 5. After that, something happened, I think a developmental rewiring of the brain caused him to forget almost all his baby and toddler memories. I still remember things we did but he can no longer reach those times. His current memory goes only back as far as about 5. Maybe this is normal for kids.

Memory doesn’t really work that way. Not like a muscle, and not really like a hard drive with a limited amount of room. But it kind of does works both ways.

The theoretical number of things your brain could remember is incomprehensibly vast, certainly beyond what any human could ever experience, but the manner in which they are remembered is not one of perfect and universal recording and recall, as you doubtless know. It will also often be just insanely wrong, which is why people will often insist they remember things that just did not happen, even very important thing or things you’d expect a person will never forget. (The classic example of this is how people can often have vivid but totally wrong memories of where they were when huge events happened, like 9/11.)

However, your brain WILL crowd memories out to store other ones. That said, it’s unlikely your brain is causing you to forget where you put you car keys so it can store a Simpsons quote; rather, your brain will often store a new memory over one that is similar. Your brain isn’t a hard drive; it’s an organ that serves to maximize your survival and so will store, access, recall and delete based on evolution’s determination of what matters.

Memories are often of feelings, emotions, senses more than of data, and they can overwrite and jumble with each other.