What about your ability to understand and process new information?
I'm finding almost everything to be much easier to understand now, compared to how it was when I was younger. Back then, I could focus, read at much faster speeds and my memory seemed way better, if measured by the amount of information I could remember. Entire texts were memorized with one or two passes. But then I'd have to spend time figuring out what to do with the information.
Now, my feeling is that wherever data I absorb is slotted right next to familiar concepts, so even though I read slower, the amount of 'post-processing' is much reduced.
It feels like a compression algorithm. "This new concept is like A and B, except for X, and Y, which are similar to Z". Sometimes, I caught myself saying that aloud. I've had to develop coping mechanisms however, to avoid jumping to conclusions, as my brain loves to do.
Entirely unfamiliar concepts are now way harder. From foreign languages (with different roots) to... Haskell.