Development of size constancy in children: a test of the proximal mode sensitivity hypothesis.

In two experiments, we attempted to replicate Shallo and Rock's (1988) finding that 5- and 6-year-old children exhibit size constancy for a distant object when tested with comparison objects that are matched for visual angle. Experiment 1 (N = 80) included four age groups: 5-, 6-, and 9-year-olds and adults. Participants viewed one standard object from 61 m and indicated which of nine nearby comparison objects matched the standard object in size. The comparison objects subtended equal visual angles in one condition and different visual angles in another. In both conditions, the 5- and 6-year-old children underestimated the size of the standard object, whereas the 9-year-old children and adults made nearly accurate size estimates. In Experiment 2 (N = 32), we replicated the finding that 6-year-old children underestimate size when tested with comparison objects that subtend equal visual angles. Our results conflict with those of Shallo and Rock and support earlier findings that young children do not exhibit size constancy for distant objects.