This Scientific American article explores how magicians use the brain’s wiring to produce illusions.
For example, “change blindness” is the tendency of a viewer not to notice significant visual changes in a particular scene if they are masked by a temporary flicker, rapid movement, or other interruption (for a dramatic demonstration, watch this video). Because the pre- and post-change environments cannot be compared side by side, the changes are missed.
The article gives other neat examples, too, like the tendency of our visual system to follow movement, which can be covertly manipulated by the magician with head or hand movements. Straight or curved hand motions affect our visual system in different ways, producing different levels of attention on the gesture.