The relationship between early language, symbolic play, sensorimotor skills and social development was examined through a longitudinal study of two autistic boys. One boy was observed from the age of two years to four years and five months old, and another boy was observed from the age of one year and eight months to four years and one month old.
One boy acquired speech, but the other boy did not.
Temporal correspondences between early language development and symbolic play were found in the case of one boy. The emergence of nominal words corresponded to the onset of substitution play, and word-chains co-occurred with the onset of combinatorial symbolic play. Concerning sensorimotor skills, both boys passed VI stage of means-ends and causality, and performed combinatorial tasks well even when they had few words. They were deficient in drawing.
Both autistic boys were deficient in symbolic functions which included language, symbolic play and drawing, but when one boy attached to a particular adult and began social interactions, the development of language, symbolic play and drawing was observed.
This study suggests that symbolic abilities are learned in the context of interaction with others.