The display below is an interactive demonstration of Ternus
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 CLOSER button brings the dots closer, and the FARTHER
button moves them farther away. 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. With shorter ISIs, you will
see the two dots move together back and forth as a group. With longer
ISIs you will see the middle dot stay put, and the outer dot jump back
and forth around it. Both motions are entirely the construction of
your own visual intelligence. To find out more about how you see this illusion
and other illusions, see the book
Visual
Intelligence, by Donald D. Hoffman.