This proposal deals with the development of the ability to perceive the shapes of objects and their layout in space. Sensitivity to one class of spatial information, the static-monocular or pictorial depth cues, appears to develop at a later age than sensitivity to kinetic or binocular depth cues. A long-term goal is to use developmental studies to understand how the human visual system extracts three-dimensional layouts from static-monocular information. The pattern of development of responsiveness to these cues may reveal how the mechanism that detect this information are related. If the onset of responsiveness to several cues occurs in a simultaneous rather than in a staggered fashion, this would suggest that the development of a common mechanism is responsible. The role of maturation and experience in the development of sensitivity to pictorial cues will be studied by contrasting the responsiveness of preterm and postterm infants. In addition, the hypothesis that the spatial meaning of pictorial cues is learning through association with binocular information will be examined by studying the development of sensitivity to pictorial information in infants who lack binocular depth sensitivity. Two methods for assessing spatial sensitivity will be used in the proposed studies. One method will measure the accuracy of reaching to the closer of two objects. The second measure will use recovery from habituation of looking to assess whether infants perceive the spatial layout specified by a pictorial display.
