Abstract
The relationship between early language and gestural communication, symbolic play, and sensorimotor skills were clarified through a longitudinal study of two boys with autistic disorders. One boy was observed from the age of two years to four years and five months, and the other boy was observed from the age of one year and eight months to four years and one month. They performed the tasks of stage VI in the sensorimotor skill of means-ends, causality, and object performance and were good at combinatorial tasks, even when they had no speech. But they had impairments in symbolic function including language, proto-declarative gestures, symbolic play and drawings.
The first boy produced the referential words and proto-declarative gestural communication at the age of three years and seven months. In his case, temporal correspondences between early language development, proto-declarative gestures, symbolic play and drawings were found. The attachment to a particular person enabled him to develop the symbolic function. The importance of social interaction with others in the formation of symbolic function was discusssed.
