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Intellectual Disabilities

An intellectual disability, formerly referred to as “mental retardation”, is not an inherent trait of any individual, but instead is characterized by a combination of deficits in both cognitive functioning and adaptive behavior. The severity of the intellectual disability is determined by the discrepancy between the individual's capabilities in learning and in and the expectations of the social environment.

It should be noted that while the term “mental retardation” is still widely used within education and government agencies; however, many advocacy groups feel that this label has too many negative connotations. The newer terms of intellectual disability or developmental disability are becoming far more accepted and prevalent within the field.


Prevalence ratings for intellectual disabilities are inconsistent, highlighting the often hidden nature of intellectual disabilities within other disability classifications. The U.S. Department of Education reports 5,971,495 students receiving special education services in the 2003-2004 school year. Of that number, 9.6%, or 573,264 students, received special education services based on a classification of intellectually disabled.

The large majority of individuals considered intellectually disabled are in the mild range with an IQ of 50 to 70. For many of these individuals, there is no specific known cause of their developmental delays. The validity and reliability of the IQ tests used with these individuals are often in question. However, if a student is evaluated and scores an IQ of 70 or lower, he or she is considered to have an intellectual disability. The problems with these labels are that the guidelines can be altered, as in the 1970s when eligibility guidelines shifted and thousands that were previously "mentally retarded" were miraculously “cured” by changing federal regulation.

The two characteristics shared in varying degrees by all individuals with intellectual disabilities are limitations in intellectual functioning and limitations in adaptive behavior. Limitations in intellectual functioning often include difficulties with memory recall, task and skill generalization, and these students may demonstrate a tendency towards low motivation and learned helplessness. Issues in adaptive behavior may include difficulties with conceptual skills, social skills and practical skills. Individuals with intellectual disabilities also often exhibit deficits in self-determination skills as well, including skill areas such as choice making, problem solving, and goal setting.

Students labeled as mildly intellectually disabled demonstrate delays in cognitive, social, and adaptive behavior skills within typical classroom settings. Often when they are in different settings, these same individuals function quite capably both socially and vocationally. In their adult lives, these individuals can be independent and well-adjusted in the world outside of school settings. It is only in the context of academic demands and intensive intellectual challenges that their abilities appear impaired. This type of school-based diagnosis has been referred to as “six-hour retardation”, reflecting the time the student is actually in the classroom and appears to be academically impaired. The assertion that intellectual disabilities is a school-based diagnosis underlines the often arbitrary nature of eligibility requirements in this disability category for future adult services. A label of intellectual disabilities prior to age 18 is necessary for individuals to receive specialized services beyond high school.

With the appropriate supports in place, students with intellectual disabilities can achieve a high quality of life in many different aspects. Curriculum and instruction must be carefully modified to help these students reach their potential in both academics and other functional areas such as independent living. While these students will have limitations in many adaptive behaviors, these limitations will co-exist alongside strengths in other areas within the individual. Independence and self-reliance should always be primary goals of all instructional strategies employed with students with intellectual disabilities.

However, a child with a significant intellectual deficit will not be able to cognitively “catch up” to his peers in terms of intelligence and academic performance. In fact, the opposite is more often true and the child will fall further behind as he gets older, particularly if no appropriate academic supports are implemented. Even with a good program in place, the cognitive and academic gap between these students and their typically functioning peers often widens with age. The child with developmental delays will learn and understand far fewer things at a much slower pace than the average child, and intellectual development will always be significantly impaired. However, the child with the intellectual deficit will continue to learn and understand some aspects of the world, but this cognitive growth is less complete and there will remain significant gaps in the student’s knowledge base. Because new learning is filtered through a younger mental context in children with developmental delays, the quality of what is learned and how it is applied will be far different than the perspective of a typically developing peer.


There are a number of excellent organizations that can help support classroom instruction for students with intellectual disabilities. The information presented in this module is intended as just a very brief description of an intellectual disability and its impact on learning. Much more in-depth information and instructional strategies can be accessed through the following organizations:


  • American Association on Intellectual and Developmental Disabilities.

AAIDD promotes progressive policies, sound research, effective practices and universal human rights for people with intellectual and developmental disabilities.

444 North Capitol Street, NW, Suite 846
Washington, DC 20001-1512


  • Best Buddies

Best Buddies® is a nonprofit 501(c)(3) organization dedicated to enhancing the lives of people with intellectual disabilities by providing opportunities for one-to-one friendships and integrated employment. Best Buddies has six formal programs for individuals with intellectual disabilities at various ages and stages of life.

100 Southeast Second Street, Suite 2200
Miami, FL 33131


  • Center for Disability and Development

Dept. of Educational Psychology
4225 Texas A&M University
College Station, TX 77843-4225


  • Elwyn

Elwyn is a non-profit human services organization recognized nationally and internationally as experts in the education and care of individuals with special challenges and disadvantages. Their goal is to help people with special needs maximize their potential and live happier, meaningful lives through residential services, education, rehabilitation, and vocational and employment services.

111 Elwyn Road
Elwyn, PA 19063


  • National Association for Down Syndrome

NADS is the oldest organization in the country serving individuals with Down syndrome and their families. Their mission is to ensure that all persons with Down syndrome have the opportunity to achieve their potential in all aspects of community life by offering information, support, and advocacy.

Post Office Box 206
Wilmette, IL 60091


  • TASH (formerly The Association for Persons with Severe Handicaps)

TASH is a civil rights organization for, and of, people with intellectual disabilities, autism, cerebral palsy, physical disabilities and other conditions that make full integration a challenge. They provide information, linkage with resources, expert assistance toward fighting inequities, legal expertise, and targeted advocacy.

1025 Vermont Avenue, NW 7th Floor
Washington, DC 20005


  • The Arc of the United States

The Arc is the world's largest community based organization of and for people with intellectual and developmental disabilities. It provides an array of services and support for families and individuals and includes over 140,000 members affiliated through more than 850 state and local chapters across the nation. The Arc is devoted to promoting and improving supports and services for all people with intellectual and developmental disabilities.

1660 L Street NW, Suite 301
Washington, DC 20036


  • Voice of the Retarded

Voice of the Retarded (VOR) is the only national organization that advocates for a full range of quality residential options and services for persons with intellectual disabilities, medically fragile conditions, and challenging behaviors. They advocate for appropriate placement and watches and acts when legal actions in any state threatens residential choice or guardianship issues.

5005 Newport Drive, Suite 108
Rolling Meadows, Illinois 60008



                                                            ---Project Ideal

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