Apparently you can tell how people think by the way they move their eyes.

up and right (their right) - for constructed, imagined images e.g. you floating on air or you with blue hair

up and left - for remembered images e.g. scenes from your holiday

sideways right - for constructed sounds e.g. your boss talking in a donald duck voice

sideways left - for remembered sounds e.g. your favourite piece of music

down and right - for feelings and internal emotions e.g. the touch of silk

down and left - for internal dialogue e.g. what you say to yourself before you give an important presentation

straight ahead, defocused - for visual images remembered or created e.g. the faces of your close friend

- Sue Knight, NLP at Work

To confuse matters left handed people may have the meaning of looking left and right reversed.