I am currently watching a wonderful lecture series from The Teaching Company called “Understanding the Secrets of Human Perception”. In lecture 18 “Illusions and Magic” Professor Vishton walks through a number of interesting perceptual illusions.
The first is the Café Wall Illusion:
All of the horizontal lines in this image are perfectly straight, but we infer a tilted edge because our brains decide that this is the best explanation for the distributions of brightness in the image.
The next perceptual oddity is motion-induced blindness. Stare at the green dot in the center of the video and watch the green dots disappear:
The yellow dots are always displayed above the grid and are therefore projecting on your retina for the entire length of the video. However, deep in your visual perception system the motion signals override the yellow dots. Motion can often blind us to very large and salient things in the world around us, something which magicians often use to their advantage.