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This paper offers a comprehensive look at the role of the visual cliff in the study of child development. First, the study of depth perception will be explored briefly to illustrate the underlying reason for the invention of the visual cliff. Second, the visual cliff and the original experiments will be presented. Finally, the variations of the visual cliff by researchers to study other areas of child development, which are linked to depth perception, will also be analyzed.
Depth perception of young children/infants: Binocular perception and stereopsis
Depth perception depends on two components, binocular perception and stereopsis. Binocular perception occurs when both eyes are able to work together and focus on one visual object at the same time. Because of the distance between the two eyes, the two retinas are stimulated differently, thus enabling one to assess how far one is from the object. Stereopsis involves the combination of two separate images from the eyes into one integrated image in the brain. The process of depth perception enables one to see three-dimensional images even when the retinas registers two-dimensional pictures. The transformation from two-dimensional to three-dimensional images occurs in the brain that has learned to manipulate visual images by comparing sizes, orientations, object overlaps and shadows (Berk, 1997; Siegler, 1998, p. 121).
Before the age of four months, infants do not have binocular depth perception. The images transmitted from their eyes reach the same cells in the visual cortex. However, once they are four months old, infants typically develop depth perception when the neural pathways from the eye to the brain are separated. While visual images from the left eye reach some cells in the brain, the images from the right eye arrive at other cells. The differences in the input transmitted from the two eyes enable the brain to produce depth perception (Siegler, 1998, p. 121). ...