We do not establish sizes, distances, directions, singly and then compare them piece by piece. Typically we see these characteristics as properties of the total visual field. (…) The various qualities of the images produced by the sense of sight are not static. (…)
Visual experience is dynamic. What a person or animal perceives is not only an arrangement of objects, of colors and shapes, of movements and sizes. It is, perhaps first of all, an interplay of directed tensions. (…) these tensions are as inherent in any perceipt as size, shape, location or color. (…) these tensions can be described as psychological “forces”. (…)
There are, then, more things in the field of vision than those that strike the retina of the eye. (…)
For any spatial relation between objects there is a “correct” distance, established by the eye intuitively. (…)
Wherever the disk is located, it will be affected by the forces of all the hidden structural factors. The relative strength and distance of these factors will determine their effect in the total configuration.
If influence from a particular direction predominates, there results a pull in that direction. When the disk is put at the exact midpoint between center and corner, it tends to strive toward the center.
(…) In ambiguous situations the visual pattern ceases to determine what is seen, and subjective factors in the observer, such as his focus of attention or his preference for a particular direction, come into play. (…)
When conditions are such that the eyes cannot clearly establish the actual location of the disk, the visual forces discussed here may possibly produce genuine displacement in the direction of the dynamic pull. (…) We shall have many occasions to observe that physical and psychological systems exhibit a very general tendency to change in the direction of the lowest attainable tension level. Such a reduction of tension is obtained when elements of visual patterns can give in to the directed perceptual forces inherent in them. (…)
(…) a visual pattern consists of more than the shapes recorded by the retina. (…) In perceptual experience, this stimulus pattern creates a structural skeleton, a skeleton that helps determine the role of each pictorial element within the balance system of the whole; it serves as a frame of reference, just as a musical scale defines the pitch value of each tone in a composition.
