A few years ago we reported on fascinating eye movement research. If you stare at a horizontal line first, then a circle appears stretched out, like an ellipse. This simple fact was ingeniously used in an experiment to study how signals from the eye are processed. Our eyes move several times per second. If we were aware of what our eyes were seeing we’d have difficulty making sense of such rapid movements. As it is we don’t sense such movements, and one theory held that the signal processing in our vision system deleted certain scenes to keep the image steady in our brains. But when human subjects were shown a horizontal line too quickly to be sensed, they nonetheless then saw a circle as an ellipse. In other words, even those scenes of which we are not aware have an effect on the scenes that we do see. Now an equally ingenious and complicated experiment helps to explain tiny eye movements of which we are barely aware. Read more