Findings from relevant research applying Piaget's theory to mental retardation, psychosis, and autism are reviewed. Many autistic individuals show an arrest in operative functions at the sensorimotor functions. The early arrest interferes with subsequent development of higher-level conceptual, symbolic, and social skills. (Author)

Educational implications and symptoms are described for learning disorders, the disruption in the processing of information within the central nervous system caused by brain damage, emotional disturbance, or inadequate presentation of learning experiences. Developmental sequences, developmental progression, and restoration of development are…