Hello Peter.I don't know why our mind blocks out some things and not others. It may be a case of we don't like a subject . I know I have no musical skills because I never cared enough about the music to develop them. However I liked math and did excellent until university and I ran into advanced calculus. I passed but barely, I just couldn't wrap my brain around the more abstract ideas of advanced calculus.
Like wise trying to learn french, I liked french, studied it so much that I was able to read in french, but I never could speak it well and I never could take part in a proper conversation. My brain just wouldn't allow me to think in french and I sure tried.
On the other hand, I've known artists that were extremely gifted doing art, theater, song, dance etc, but who I wouldn't let change the oil in my car. No mechanical aptitude they might drain the radiator and fill it with oil.
I suspect that our individual brains are as guided by genes and envoirnment as our physical abilities are. I mean someone who is 5 ft tall and weighs 100 lbs is never going to lift a 500 lb weight. However that same person may have a terrific athletic ability in another area that a 6ft 250 lber could never do (say being a jockey). He/she, just wasn't given the genes to grow to the size required. I suspect it's the same with our brains. No matter how much we try to do some types of heavy lifting our individual brains just may not be able to do it. Doesn't mean we are dumb, we just don't have the requirements to be able to do that task. Take Care. paul m