Figure 1.2

Apparent Motion and the Phi Phenomenon

In each case, imagine that form 1, by moving at a carefully timed speed in the direction of the dotted line, becomes form 2. The resulting illusion is apparent motion, which we perceive when an object ceases to be at point 1 and reappears at point 2 without really crossing the space between. The top figure is also a good example of the phi phenomenon, which is an instance of apparent motion caused by flashing lights. Note that, in all three cases, the illusion works because the pattern of movement from point 1 to point 2 is the most “reasonable” pattern of movement.

Back to CHAPTER 1/Part 1