I would honestly be very surprised if you actually kept track of every visual detail verbally.
Sorry, I didn't really explain this very well - I'm not tracking them verbally. In fact, most of the time I don't tend to represent my thoughts verbally either (something else that seems to surprise people when we discuss how we think), they exist in the same state that my spacial representations of things do - at least until I need them in a verbal form (such as when I'm trying to decide on the wording of something I'm going to say or write). It's hard for me to describe the state my thoughts take to someone else, as there's no analogue outside of my own head. When I said:
I can remember details of appearance, but they take the form of 'has ~5cm, dark straight hair', rather than a picture of how said hair might look.
What I meant is that there are some sort of symbols in my mind that represent these concepts being activated, but in a more abstract way than by using the words that describe them, or by picturing the images that make me think of them. It feels a little like there's a more abstract layer that sits on top of my visual and verbal systems, and this is where I do my thinking and imagining. If I need to, I can 'bring my thought down' to these parts of my brain (like when I'm deciding what to write, or how to draw something), but it's not the default case.
It seems to me like your visual cortex is processing the "picture" but for some reason you aren't experiencing it directly...
I guess this could be a possibility, but I do experience the "picture" to a degree if I actually make an effort to visualise it, like when I'm trying to draw a scene from my imagination. It's not really anything like what I see when I'm actually looking at something, but I assume that's the case for everyone. For example, if I try to do a puzzle that involves picturing something from a different angle, I'm able to, but it takes a conscious effort. The process I use for this doesn't seem to get involved when I'm imagining a scene from a book (unless I'm doing something like trying to picture a scene from someone else's point of view, at which point I have to stop reading briefly while I build up a picture).
Previously: Generalizing From One Example
Summary: I do not have visual mental imagery. I want it. How do I get it? What exercises, if any, will help?
In further detail... Here's Francis Galton's Statistics of Mental Imagery paper. I'm not quite at the 3% level of completely unable to form mental images, but I'm close. In particular there are three times I have vivid, sharp mental imagery, and the existence of such times tells me I have the brain hardware to visualize. It's enough to let me know that I want it all the time. Unfortunately I don't know how to get it. And searching online has proven difficult and frustrating... for example this article is first of all about a different meaning of "visualize", it's talking about some kind of self-help motivational thingy, and second of all it starts by saying "How to Visualize: I want you to relax and close your eyes. Picture a hot, sunny day at the beach."
Full Stop. Halt, Catch Fire and Burn.
That's already too far. For those of us who don't visualize, practice definitely does not consist of pulling up mental images, playing with them in new ways, and expanding our imagination. I'm very good at imagination in some ways, but I lack that first ability to pull up a mental image. That's what I want to learn how to have!
Here is a description of what I can do, what I have tried, what I have learned, etc.
I see vivid visual mental imagery in 3 situations: