 |
|
Constancy Our senses do not respond to absolute values of a stimulus, but rather changes of stimulus. We rapidly get used to new information unless it is constantly changing. This ability to screen out constant sensory input is invaluable when listening to a friend at a busy party, but can have unexpected effects, as seen in these illusions.
|
 |
 |
||||||||||||||||||||
|
Which side of the grey ring is darker? Click the arrow to spin the central bar. Now which side is darker? Restore the bar with another click of the arrow. |
This figure is being illuminated from the left by lights of different colours (as seen in the left hand shadow), and from the right by a constant white light source. In all cases the right hand shadow is a neutral grey and unchanging since there is no source of coloured light on that side. How does it look to you? Do some colours give better effects than others? This ground breaking experiment was suggested by Goethe and upended conventional Newtonian colour theory. |
Which one of these panels is darker? In actuality both panels are the same. The illusion results from their tonal gradient and the juxtaposition of the dark edge of the right hand panel with the light edge of the left. |
Stare at the dot for 30 seconds and then look at the white background. What do you see? What is the relationship of the colours on the picture to the colours you see as an after image? What happens when you blink? |
|
