Compared was the performance of 17 preschool and 10 early elementary educable mentally retarded (EMR) children with the performance of 50 normal preschool children on a developmental sequence of tasks in visual perception. Tested were the skills of recognition, discrimination, recall, and reconstruction of common objects, size concepts, shape concepts, color concepts, and combinations of dimensions. A developmental progression from simple recognition through reconstruction was observed in both normal and EMR children, though younger EMR children performed better on the representational tasks than on the concrete tasks. Implication for the training of young EMR children included the presentation of tasks in steps from recognition to reconstruction, the designing of tasks to minimize the effects of poor motor coordination, the provision of practice with both concrete and representational materials, and the use of a game format to increase motivation. (See EC 052 240 for a related document). (DB)