Abstract
This paper reconsidered the meaning of developmental stages in the study of developmental disorders, especially in the case of autism spectrum disorder. First, "The Theory of Hierarchies and Stages on Reversible Operations in Human Development (Tanaka, 1980)" was reviewed from the viewpoint of developmental stage theory. Second, the significance of the theory of mind deficit theory was reviewed from the standpoint of developmental stage theory. It was found that theory of mind deficit theory consisted of domain specificity and the denial of qualitative change. Third, in explaining the mechanism of symptoms in autism spectrum disorder, it was important to take into account the developmental relationship. Finally, the developmental relationship makes it possible to open a new direction in practices to enhance several abilities that constitute developmental linkages.
