All artists want a better memory. In The inside story of Viz, Chris Donald says of co-cartoonist Graham Drury:
Graham had an uncanny ability to draw anything at all, entirely from memory. He was a graphic reference library. For example, a cry would go up of, 'Graham, What does an Anglican bishop's hat look like from the back?' and he'd draw one instantly.
But not everyone is as lucky as Graham, as the thread "I cannot mentally visualize." on Metafilter shows. (In case the site disappears, I've archived it in the Wayback Machine.) Discussion was kicked off by "gibbsjd77" saying that until he was 15, he'd never realised that other people could visualise things. Because he can't: he can't see his mother's face, a lemon, a house. It was only when discussing it with a friend that he realised some people can clearly see things in their minds.
And let me back up gibbsjd77 here - for all the people trying to help us build up our skill with visualization exercises or something, it doesn't help; our brains just don't work that way. It's like suggesting to someone with no arms that he should lift weights.
But is that really so? Right at the end of the thread, user "fritillary" contradicted dfan's experience:
I adamantly disagree that visualization is a 'got it or not' skill. Two years ago, I was in your place exactly... I couldn't summon colors, lines, even my own face at will. Growing up I never had mental or sensory imagery. Every bit of my thinking was done in words and numbers. [...] Now I see images and feel body-flashes all the time. No lie, it has been exceedingly difficult to get this far. When you seem to lack every possible starting component, it's like asking a seahorse to skateboard. [...] The rewards are astounding though. The closest thing I can think of is learning a second language... but it's so much better than that! It's a whole new way to THINK. I've put myself through the wringer to learn and I am a different, happier, more complex person because of it. It was months before I saw any results, but god what a taste of fire.
Fritillary went on to suggest things that might help: recalling one's dreams; lucid dreaming; meditating to build concentration; working with one's hands; taking art classes; drawing with one's left hand or one's feet. Paying close attention to how objects look and change, and to size, line, value, surface, light, texture. Asking oneself questions such as "Where is this orange in relation to that one over there? Where do they both lie in my visual field? How is this shade of red different from that one? If I rotated this orange 90 degrees to the left, how would it look?"
And, making visual imagery one's only mental language:
Arm yourself with questions in the thought-systems you know (language, music, touch, taste), but don't let yourself answer in anything but sight! If you start thinking in words push them away. Build your memory: look at a orange, look away, try to recall. Repeat. Repeat. Do the same with every visual scene in front of you until you can see afterimages. Try imagining objects in new positions, add features that don't exist. Set up Rube Goldbergs. Compare and contrast. Work your way from hazy generalities to clear microdetail.
But has this really worked? A neurologist I discussed it with pointed out that Fritillary's new abilities had not been objectively tested. She might only believe her powers of visualisation have increased. So is it worth spending time on the kind of exercises Fritillary did?