A New Perspective Emerges – An Emphasis on Personhood and Development
In 1959 Danish law incorporated the principle of normalization. N.E. Bank-Mikkelsen, Director of Mental Retardation Services in Denmark defined normalization as "letting the mentally retarded obtain an existence as close to the normal as possible".
Bengt Nirje, the Secretary General of the Swedish Association for Retarded Children expanded the idea to the quality of life experienced by children and adults. He argued that people had rights.
Normalization means… living in normal housing in a normal neighborhood.
Not in a large facility with 20, 50 or 100 other people because you are retarded.
And not isolated from the rest of the community.
Normal locations and normal size homes will give residents better opportunities for successful integration with their communities.
As people from North America visited services in Scandinavia, they learned that people who were seen as "severely and profoundly retarded" could learn things and live in ways thought impossible in North America.

The Principle of Normalization
The principle of normalization had a major impact on our ability to see the tremendous impact attitudes, values and environment have on people with disabilities, and the ways that other citizens understand their roles in the lives of people with disabilities.
The idea that we see people with disabilities having the same needs as all people (that they are "people first") and that the environment can hold people back as much as any condition they might have grew out of the principle of normalization.
In 1969, the International League of Societies for the Mentally Handicapped recognized that "the Principle of Normalization is a sound basis for programming". The ILSMH also stated that "the great majority of the retarded are ordinary people with an ordinary person's needs."
From "The Six Hour Retarded Child"


The Developmental Model
One of the key concepts that emerged with the principle of normalization was the developmental model – all people have the capacity to grow and learn regardless of the degree of their disability.
The model shifted the focus from medical approaches to teaching approaches. For some, "mental retardation" stopped being an "affliction to be cured". Earlier models emphasized the static nature of the condition and diagnosis. The developmental model stressed supporting people to learn skills that would assist them in their everyday lives.
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.

Lou Brown