The first two are probably the most commonly used:
1) Internal, or First Person perspective - where you imagine what you actually experience during the scenario (hear, taste, feel, see, smell).
2) External, or Third Person perspective - you image as if watching yourself on videotape, like a spectator.
I find both of these techniques useful when learning new movements or skills. By using both perspectives and mentally rehearsing the kata movements or knife disarms (for
example), it can accelerate learning and retention. First I image using the internal perspective. If there’s a part that seems unclear or not fluid, I’ll often switch to
the external perspective and rehearse what it should look like. It’s also a viable technique if you can’t “see”yourself doing the move: “remember” what it looked like when your instructor, sensei, or coach did it, then “see” yourself doing the same movement externally. Then move back to the internal perspective to really lock it in.
The final two perspectives mentioned by Asken, Grossman and Christenson are:
3) Other - how your adversary will view you and your actions
4) Top-Down view – as if you were observing from above your actions, like from a blimp.
This is said to allow for an evaluation of tactics and strategy and to step out of the action for analysis.
Bottom line is that some of these work better than others depending on individual preferences and learning styles. If you’re not familiar with all four, why not try a new one and see what happens?