Haptic estimates of discordant visual-haptic size vary developmentally.

In two size-conflict experiments, children viewed various squares through a reducing (1/2) lens while manually grasping them through a hand-concealing cloth. Then, using either vision or touch, they selected a match from a set of comparison squares. Forty 6-, 9-, and 12-year-olds participated in Experiment 1. Vision dominated the visual estimates of all three age groups; however, for the haptic estimates, the dominant modality varied developmentally: Vision dominated the 6-year-olds' haptic estimates, whereas neither modality dominated the 9-year-olds' haptic estimates, and touch dominated the 12-year-olds' haptic estimates. In Experiment 2, 24 six-year-olds were tested, as in Experiment 1; however, half of them were shown the size-distorting effects of the lens just prior to testing. Although this reduced the visual dominance of their haptic estimates, the effect was weak and short-lived. The haptic dominance seen in the data of the 12-year-olds was conspicuously absent.