ABSTRACT
The American Association on Intellectual and Developmental Disabilities, founded in 1876, has led efforts to understand and ameliorate intellectual impairment. This organization has long provided conceptualizations of intellectual disability that have often been adopted by other professional groups. In its latest manual, published in 2010, it offered the following definition:
Intellectual disability is characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical adaptive skills. This disability originates before age 18 (Schalock et al., 2010, p. 5).
