I recently realised why I cannot do mental arithmetic and it is due to how my mental visual imaging works. If I think of something visual, or consciously remember something I have seen, I get an overall impression, it is very generalised and quite 'fuzzy'. I can then mentally zoom in on a detail of the image and that is sharp. I can draw fairly well and can draw horses (which are considered relatively difficult subjects) from memory. My visual imaging 'system' is fine for doing that, I can get the overall proportions right from my fuzzy general image and then mentally zoom in, for example, to get the shape of a nostril. My visual system does not work for arithmetic, though. I can visualise one number, but if I try to mentally arrange a sequence of them to add or subtract then all the numbers other than the single one I am concentrating on just dissipate into nothingness.
I was wondering if, like Temple Grandin, anyone here can visualise objects in great detail and rotate them mentally to view from different angles? Also, in general, how people's mental processing of images differs.
