As a child matures from infancy to early childhood, a shift occurs in his sensory hierarchy from tactile to auditory to visual. The transition between the predominance of the auditory sense and visual sense takes place in about grades four and five. Although the sensory systems do not function singularly (but are integrated in the total action system of the child), the child's general academic development is significantly linked to his perceptual development. Thus, it is important that a child's perceptual development be adequately measured. Such measurement can be accomplished through the use of many types of geometric-form tests. His visual perceptual span can be measured with a tachistoscope. Not only is it important to determine the child's sensory and intersensory development in order to be able to respond to his academic needs, but perceptual organization is important in the development of a positive self-image. (WD)