Eye movements lasting only a few hundredths of a second create an information-laden ‘smear’ of the retina.
When we look at a scene, our eyes dart from one point to another about three times a second. While we don’t perceive this rapid-fire flicker, experiments reveal that it produces visual information that helps us make sense of the world around us.
To see in sharp detail, a person’s eyes often focus on objects in their peripheral vision. These extremely rapid eye movements create ‘movement lines’, visual blotches, at the back of the eye. A line of motion extends from an object’s initial position on the retina to its position after eye movement.
Richard Schweitzer and Martin Rolfs of the Humboldt University of Berlin showed volunteers six different patterned objects and asked them to focus on one object. The positions of the objects changed as the volunteers’ eyes moved towards that target. The researchers then overlapped all the objects with the same pattern, making them indistinguishable.
Participants successfully found the target in most cases, but were more likely to do so if their movement created a line of motion. This suggests that information gathered from the lines helps our flickering eyes track where objects are.