There is a story that one of the animators in the 1940s Warners studio got into a car accident, and suffered a mild concussion. When he recovered, he found that

There is a story that one of the animators in the 1940s Warners studio got into a car accident, and suffered a mild concussion. When he recovered, he found that his visualization was much improved - suddenly he could visualize the simple construction of the characters, and "trace" it directly onto the paper. This resulted in him being able to draw a lot faster, so that's a pretty obvious test. (IIRC I got this story from Chuck Jones' autobiography, if you want citations.) My personal experience as an artist is that some strains of marijuana can give my visualization abilities a temporary boost into that domain; a lifetime of regular drawing also tends to improve these skills - I'm fifty, and I can skip a lot of steps that younger me couldn't. I generally like to describe the process of learning to draw as "installing a 3d renderer and a library of models on your brain".