One concept they use is 'modality' or 'preferred representational system' (might be familiar if you have studied NLP). This is the idea that people's internal thought processes are predominantly visual, audial, kinaesthetic (touch-oriented) or verbal/digital (that's like a stream of internal words). I'm not sure about this. Many people think it's unscientific or over-simplistic.
Having said that, I am sure it is easier for some people to visualise (just for example) than it is for others, and one would be foolish not to take it into account. A similar issue exists in education, where there is debate as to whether pupils can be divided according to learning styles and what is the most appropriate division to use.
I believe my internal processes are largely kinaesthetic (or perhaps, just more kinaesthetic than average). For example, to remember dates, I imagine a long band which runs around my body, which I can turn to look at. When I evaluate a logical argument I feel it as a tight or smooth pressure. To some extent anyway.
You can see where I'm going here: Do you think there is any validity to this method of classifying people? And how would you classify your internal representation style?