What role does AAIDD play in defining mental retardation and intellectual disability?
AAIDD, the world’s oldest organization of intellectual disability (ID) professionals, has played a major role in evolving ideas about and approaches to intellectual disability. In fact, the association, founded in 1876, revised its definition of mental retardation ten times between 1908 and 2002. The first definitions of mental retardation focused on a failure to adapt socially to the environment. Later definitions added a medical approach that considered heredity and pathology and called for the mentally retarded to be segregated. Then the rise of the mental testing movement brought an emphasis on measuring intellectual functioning by IQ test. The IQ test became the way to define the group and classify the people within it. In its 1959 definition and classification manual, AAIDD first attempted a dual-criterion approach: a definition that mentioned both intellectual functioning and “impairments in maturation, learning, and social adjustment.” In its 1961 manual, AAIDD folded the “impa
