In Zollner's illusion of direction, parallel lines appear to be bent when other lines cross them at an angle. The illusion disappears when the image is held far enough away from the eye to distinguish the short crossing lines. Some scientists say that face recognition is performed by a particular section of the brain. To the brain, this image of Lincoln's face looks normal when viewed upside down, but when turned around it becomes distorted.
This is because our brains recognize a face only when it is right side up. When it is presented upside down, the brain no longer recognizes it as a face but rather as an object, and this is why we do not respond to its distortions.
