Figure-ground relationship is also an important way in which perception is organized. Such relationship is fundamental to the form perception. Figure is the pattern that is most clearly perceived at a given time, while the rest of the perceptual field becomes the background. You see birds flying in the sky. Birds are the figures against the background of sky. You see the writings on the blackboard. Writings are the figures against the blackboard as the background.
Thus, a figure stands against a background. We perceive the figure and not the ground because of some characteristics of the figure, which clearly differentiate the figure from the background. Gestalt psychologists who discovered some principles that govern figure ground relationship in perception extensively studied the phenomenon.
A Danish psychologist, Rubin (1915/1958) observed the following differences in the characteristics of figure and ground relating to any perceptual activity.
1. The figure has a definite shape, whereas the ground appears to have no shape. The figure has the quality of a 'thing' and contour appears at the edge of the figure's shape. In contrast, the ground has the quality of a 'substance' and appears relatively formless.
2. The figure seems to be present in front of the ground. In other words, the ground seems to continue behind the figure.
3. The figure seems to be closer to the perceiver with a clear location in space. In contrast, the ground is farther away, and it has no clear location in space; it is simply somewhere in the background.
4. In relation to the ground, the figure appears more impressive, dominant, and better structured. The figure depicts more associations of meaningful shapes than the ground.
Besides the above four differences, Coren (1969) reported an experimental evidence for a fifth characteristic difference in the perception of figure and ground. He observed that the figure always looks brighter than the ground. There should be clear differentiation between the figure and the ground, so that there will be a stable perception of the figure.
In other words, the figure will be perceived as the figure always in different occasions. But, when figure-ground relationship is ambiguous, or is possible of being interpreted in different ways, our perception tends to be unstable. These are situations in which the figure and the ground reverse their positions frequently, i.e., the figure becomes the ground and the ground becomes the figure simultaneously. These reversals often appear almost spontaneously.