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.