When I think about things, in addition to mental images and internal monlogue, I have very vivid tactile and kinesthetic sensations. For example, if you were to say "high-heeled shoes," I would only dimly picture a pair of heels, but I would immediately imagine how they would feel in my hand, how it would make the arch of my foot feel to wear them, and the emphatic stamping sensation of walking in them. It's the same even with abstract ideas; negative numbers feel a particular way in the pit of my stomach, and factoring feels like a physical process of disassembly.