Figural or configuration aspects

Our second class of perceptual phenomena contrasts sharply with the first. Though like those in the first they are experiences arising from things in the environment, they seem even less determined by the stimulus and more determined by processes inside the organism. They exhibit strongly the effect of one thing upon another in the perceptual manifold, an effect which frequently produces optical of other illusions. They are concerned mainly with the formal properties of the thing we perceive, such as shape, outline, grouping, and the like. Looking at a circle drawn with ink on a white card, we note that the appearance of its size is altered if it is placed between parallel lines or enclosed in an angle. It can be made to appear distorted into part of a spiral by a twisting line along its course and by special features in the background. A square turned up on one of its corners looks quite different fro the way it appears when its upper and lower edges are in a horizontal position. Looking at the drawing of the circle again, but without accompanying lines or angles, we see that it encloses an area that is segregated from the surroundings, and that the line of the circle itself is a contour that seems to belong to the circle as its edge and not to be the edge of a circle hole in the background. We see that circle appears as a definite “figure” standing forward clearly and that the rest of the card seems to extend beneath it as a less vivid ground.

Figure and ground are ubiquitous aspects of perceptions.  In every sense modality our word consists of figures appearing against grounds and where other aspects are not in control there are a number of rules that determine which part shall be figures and which ground. In drawings in which either portion may serve as figure or ground there is usually a shift of the percept back and forth from one figure-ground experience to the opposite.