As a fellow can't-visualise-anything-ist, it's possible to work around it! You just have to memorise a bunch of individual elements of the thing in question, elements that are individually simple enough to be remembered as descriptions. So like a horse's head is a sphere with a tapered cylinder on the front, the cylinder being about two thirds of the radius of the sphere narrowing to half the radius. Ish.
...or, like, use a reference. Drawing things from memory is not a skill I have suffered from lacking in my life
What I was implying was not that I couldn't draw a horse (I do art after all) but rather the fact that it's not truly recalling it from memory, which was what was asked.