Do autistic children differ from retarded and normal children in Piagetian sensorimotor functioning?

Piagetian sensorimotor functioning of 10 autistic, 10 retarded, and 10 normal children, closely matched on mental age, was assessed with the Dunst revision of the Uzgiris and Hunt scales of infant psychological development. The three groups showed no significant differences in overall performance or specific subtest performance as revealed by estimated developmental ages, number of failed items, and Piagetian stage levels. These findings, which are contrary to previous reports of early sensorimotor deficits specific to autism, suggest that the long-term cognitive deficits in autism are more in symbolic thinking, which does not emerge until the end of the sensorimotor period.