afterimages - click on "select colour" then on the colour you want.

motion aftereffect - click on "induce" to start the spiral and on "timer only" to stop it.

the aperture problem - when the ends of the lines in the circular aperture are not visible,

the grating always appears to move at right angles to the bars - i.e. horizontally

barberpole illusion - in the aperture, when the bar ends are invisible, the grating appears

to move along the aperture i.e. down

The McCollough effect - after considerable adaptation, coloured aftereffects can be seen

on the vertical test gratings but not the oblique ones

Bistable apparent motion - the red squares appear to move either horizontally or vertically and these two

directions spontaneoulsy change over time

Several pairs of dots in apparent motion can entrain the motion of a single flashing dot

the Hikosaka effect: A line preceded by a dot at one end makes the line appear to grow from that end

The Ternus effect: Three dots can be seen in group or element motion

A plaid demonstration showing the plaid's two component gratings then the sum of the two - needs QuickTime Player

A "plaid" with very different component gratings produces "sliding" or "transparent" motion: here

Some downloadable demonstrations of changeblindness: when scenes change as they flash on and off or

change very slowly, changes often cannot be seen - we process the world less than we think.

A movie of a random dot kinematogram

A movie explaining Mather's example of convolution