If a person looks up and to their right they are looking in an area that will stimulate their brain to access visual or picture information related to items (ideas or thoughts) they maybe constructing or creating. Moving their eyes in this area could also be a signal that the person is accessing painful memories from their past. Contrary to popular belief, looking in this direction does not mean the person is lying.
Try it: Visualize yourself some time in the future, maybe 2 weeks or 2 days from now. Where are you looking to create this picture?
It is thought that 80% of people in North America are dominantly visual in the way that they learn and process information. This doesn't mean they aren't capable of using their other senses. They just have a preference. And, even though they dominantly use visual ways of processing it doesn't mean that they don't go through other sense to complete their processing. Generally, we use many more of our senses to process information. So 80% of North Americans (maybe) mostly start visually and then use some other sense and and then another sense and on and on - This accounts for our very different and unique learning and information processing styles and explains why so many people these days are diagnosed with learning disabilities who aren't really learning disabled.