Get a piece of A4 paper and draw a big black dot on it. Now stick it on the wall around 4 metres away directly in front of you and at around eye level. Now stand looking towards the dot, feet flat on the ground a shoulder width apart, take a deep breath and stare at the spot. Notice at this point what you can see in your peripheral vision. Now lift your hands to either side of your head and wiggle your fingers. Continue looking at the spot and move your hands, fingers still wiggling, back in a straight line heading behind you slowly. Notice how your field of vision widens and anything else that may move in your peripheral vision you notice really quickly.