The typical and atypical developing mind: a common model.

We present a theory of atypical development based on a developmental theory of the typical mind integrating developmental, cognitive, and psychometric theory and research. The paper comprises three parts. First, it outlines the theory of typical development. The theory postulates central cognitive mechanisms, such as relational integration, executive and inferential processes, and domain-specific processes underlying different environmental relations, such as visuospatial or quantitative relations. Cognitive development advances in cycles satisfying developmental priorities in mastering these systems, such as executive control from 2-6 years, inferential control from 7-11 years, and truth control from 12-18 years. Second, we discuss atypical development, showing how each neurodevelopmental disorder emerges from deficiencies in one or more of the processes comprising the architecture of the mind. Deficiencies in relational integration mechanisms, together with deficiencies in social understanding, yield autism spectrum disorder. Deficiencies in executive processes yield attention-deficit and hyperactivity disorder. Deficiencies in symbolic representation yield specialized learning difficulties, such as dyslexia and dyscalculia. Finally, we discuss clinical and educational implications, suggesting the importance of early diagnosis of malfunctioning in each of these dimensions and specific programs for their remediation.