You hear a voice in your head when you're reading, right?
If you think this is interesting, definitely read  "Generalizing From One Example" at Less Wrong [1].Turns out that people have varying degrees of ability to mentally imagine things, where the range seems to be from "purely abstract" to "number of stripes on a tiger".Also; Feynman noted that people keep track of time in very different ways[2], either visual (imagining a clock) or symbolic (counting by talking to yourself inside your head).And that whole internal monologue thing? Turns out that some people report not having that...If anyone has more examples, please add them. This stuff is endlessly fascinating :)[1]http://lesswrong.com/lw/dr/generalizing_from_one_example/[2]http://generallythinking.com/richard-feynman-on-thinking-pro...