It's easy to prove, you can think about some graph or some physical object. If you can manipulate it in your mind and can answer questions about it, then you're

It's easy to prove, you can think about some graph or some physical object. If you can manipulate it in your mind and can answer questions about it, then you're probably not thinking verbally. Say, how to go from place A to place B, if you've never travelled that route. But you know how things are laid out. Some people really struggle with this by the way.