Ironically, the "developmental model" in education has a negative consequence. Browder and her colleagues suggest that educators took a perspective that held people back.
In the absence of a curriculum model [for students with severe disabilities], professionals adapted preexisting infant and early childhood curriculum for students in Grades K to 12. This approach, known as the developmental model, was based on the assumption that the education needs of students with severe disabilities could best be met by focusing on their mental age as derived from a developmental assessment.
The work of Lou Brown and others in the 1970s challenged that interpretation of the developmental model and suggested teaching functional skills that would be useful to individuals when they took their ultimate place in the community.