Gestalt psychology
"The original observation was Wertheimer’s, when he noted that we perceive motion where there is nothing more than a rapid sequence of individual sensory events.  This is what he saw in the toy stroboscope he bought at the Frankfurt train station, and what he saw in his laboratory when he experimented with lights flashing in rapid succession (like the Christmas lights that appear to course around the tree, or the fancy neon signs in Las Vegas that seem to move).  The effect is called apparent motion, and it is actually the basic principle of motion pictures".