I think neither visually nor verbally.

Quote Originally Posted by Merlock View Post
Actually, it isn't impossible to use conceptual thought consciously. It's just very, very, very tough. But it can be trained like anything else. You do it half-consciously every time you drop into deep thought: while solving maths in your head, remembering a memory from long ago in silence to yourself for a short moment, etc.
If anyone has heard of Daniel Tammet, I have a strong suspicion he uses conscious conceptual thinking when he imagines numbers as having shapes, colors, and textures.