Meanwhile, in 1992 the AAMR definition of "mental retardation" began to reflect the shifts in perspective that emerged in the 1970s and '80s.
Mental retardation refers to substantial limitations in present functioning. It is characterized by significantly sub-average intellectual functioning, existing concurrently with related limitations in two or more of the follow applicable adaptive skills areas: communication, self-care, home living, social skills, community use, self-direction, health and safety, functional academics, leisure, and work. Mental retardation manifests before age 18. (Luckasson, 1992)
This definition recognized the interaction between the individual and the demands of the environment. Instead of defining four levels of severity, the AAMR changes to a classification based on the amount of support required – intermittent, limited, extensive and pervasive. These levels shift the focus to issues that are outside the person.
The Developmental Disabilities Acts of 1990 and 2000 more clearly recognized the needs of infants and children. Before 1990, the Act stated that a developmental disability is "a severe, chronic disability of a person 5 years of age or older".
The 1990 Act (P.L. 101-496) stated that when the term is "applied to infants and children it means individuals from birth to age 5, inclusive, who have substantial developmental delay or specific congenital or acquired conditions with a high probability of resulting in developmental disabilities if services are not provided". This validated the importance of early intervention services to prevent the development of disabilities.
In 2000 the Act shifted the age range upwards to 9 years.