blelb The visual perception lab

previous spot spot 19 next spot

You can't see blelbspot 17?

Does your browser support java applets?

Did you enable java in your browsers preferences?

This applet requires Java 1.1.8.

Move the mouse around in the picture. Stop and start the movements by clicking.
Figure and ground
One of the ways in which we perceive images is based on the principle of figure and ground. This is understood to mean the division of the image into foreground and background or main and subsidiary objects. This allocation does not always have one interpretation only and also depends on the reading habits of the viewer.
Bewildering effects can be created with optical illusions, ambiguous images in which the roles of figure and ground are interchangeable. This «tilt» phenomenon serves as a metaphor in different fields. Architects use the terms private and public, interior and exterior, as well as mass and space. Christian Morgenstern took this metaphor for his poem 'Der Lattenzaun' -The Latticed Fence: 'There was once alattice fence with gaps to see through....and took the gaps out and built a big house...'. Theologians have occupied themselves for centuries with the concept of body and soul, mathematicians and physicists have searched for order in chaos, philosophers mind in matter and substance in nothingness. Psychologists differentiate between feeling and mood, Gestalt psychologists use the terms «thing» and «medium" and neurophysiologists research the process of the separation into figure and ground in the cortex. How are dots of light processed on the retina so that certain groupings appear as figure and others as ground?