von Schiller Apparent Motion

 
 

The display below is an interactive demonstration of apparent motion.
 
 


 
 

By clicking on the buttons you can change this display in countless ways.  Each click on the SLOW button makes the dots stay on a little longer.  Each click on the FAST button makes the dots stay on a little shorter. The ISI_PLUS increases the time between the appearance of dots.  The ISI_MINUS decreases the time between the appearance of dots.  The BIG button makes dots bigger, and the SMALL button makes dots smaller.  The CLOSE_V button brings the dots closer vertically, and the FAR_V button moves them farther away vertically.  The CLOSE_H button brings the dots closer horizontally, and the FAR_H button moves them farther away horizontally.The COLOR button randomly changes the colors of the dots.  The RESET button gives back the original display.  You can now experiment and see for yourself how your perception changes as you click on these buttons.  Notice that this display is bistable: You can see the dots moving up and down, or side to side.  As you move the dots closer together horizontally, you will be more biased to see the dots move side to side.  As you move the dots closer together vertically, you will be more biased to see the dots move up and down.  To find out more about how you see this illusion and other illusions, see the book Visual Intelligence, by Donald D. Hoffman.