The development status of the communicatory behavior of 11 autistic children (4 to 9 years old) was assessed during free play sessions under two conditions: when teachers were present to direct the children's behavior and when teachers were absent and the children played among themselves. (Author)

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)