Development of sensitivity to information provided by cast shadows in pictures.

The shadow cast by an object in a two-dimensional picture can specify for the observer the spatial relations between that object and its surroundings, and also the shape and size of the object itself. Some sensitivity to this information is present even in three-year-old children. Experiment 1 provided evidence that three- and four-year-old children can rely on the shape of the shadow cast by an object to judge the shape of the object. In experiment 2, with adults and three- and four-year-old children, the location of the shadow cast by an object influenced the perceived depth and height off the ground plane of the object. Although even the three-year-old children were sensitive to the location of the cast shadows, there was evidence of improvement with age in judging the distance and size of the object. The three-year-olds were not able to judge the object's size when the location of the cast shadow provided the only differential information for size. In contrast, they were significantly better in judging size when the location of the object, rather than the location of the shadow, was varied.