Haptic-visual shape matching by mentally retarded children: exploratory activity and complexity effects.

The accuracy of nonretarded persons in shape matching within and across vision and touch improves with development, and matching by eye is usually better than is matching by hand. The pattern is less clear with mentally retarded children, however. In the present experiment we compared haptic and visual matching of retarded and nonretarded children at different developmental levels, while systematically observing variables known to have developmentally linked effects on task accuracy, including stimulus complexity and haptic exploratory search style. The results showed that accuracy depended on both stimulus complexity, modality, and mental age, regardless of whether or not children were retarded. The selection of haptic search styles also depended on these factors but, in addition, was influenced by intellectual status of the children.