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.

Impact on Learning

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.

Teaching Strategies

To fully address the limitations in intellectual functioning and adaptive behavior often experienced by individuals with intellectual disabilities, teachers need to provide direct instruction in a number of skill areas outside of the general curriculum. These skills are more functional in nature but are absolutely essential for the future independence of the individual. Additional skill areas include money concepts, time concepts, independent living skills, self-care and hygiene, community access, leisure activities, and vocational training. Students with intellectual disabilities learn these skills most effectively in the settings or activities in which they will be asked to apply these skills. Once the skills are mastered, then additional environments can be added to work towards generalization.

General curriculum areas should not be neglected however, and there are some promising practices to help support these students in a number of academic areas. One effective early literacy strategy with these students is prelinguistic milieu teaching (Fey,, 2006), a technique that ties instruction to the specific interests and abilities of the individual child. This language acquisition instructional strategy also helps support effective self-determination, as a key component of the training is frequent requesting behavior from the student.

Breaking down larger tasks into their specific component parts can be an effective technique for teaching any number of skills to students with intellectual disabilities. More complex concepts or activities can then be taught over time, and as the student masters one component of the task, another is added to the routine. This type of task analysis can be taught using a variety of instructional supports, from physical and verbal prompting to observational learning. As always, the specific instructional strategies and materials used with the student should be aligned to the student’s own interests and strengths.

Useful strategies for teaching students with intellectual disabilities include, but are not limited to, the following techniques:

  • Teach one concept or activity component at a time
  • Teach one step at a time to help support memorization and sequencing
  • Teach students in small groups, or one-on-one, if possible
  • Always provide multiple opportunities to practice skills in a number of different settings
  • Use physical and verbal prompting to guide correct responses, and provide specific verbal praise to reinforce these responses

Assistive Technology

The use of real materials or actual tools in natural environments is an essential component in the effective instruction of students with intellectual disabilities. Although these materials would be labeled as “low tech” teaching resources, they serve to both motivate the student and facilitate generalization to multiple environments. An example of this type of technology would be the use of manipulatives or concrete objects for a math lesson. Teachers should keep in mind that students with intellectual disabilities in inclusive classrooms also benefit from using the same materials as the rest of the students whenever possible. In other words, a high school student would use a calculator to work math problems whereas an elementary student may be more likely to use counting blocks.

There are a number of existing software packages designed to support students with intellectual disabilities in the classroom. One promising approach in literacy software utilizes universal design for learning principles. This approach combines reading for meaning with direct instruction for decoding and understanding. The resulting software consists of an audio and video based curriculum that can be adjusted by the teacher to meet the specific academic capacities of the student.

Ultimately, any learning software that can tailor content to address the interests of the student can be useful in supporting learning with individuals with intellectual disabilities, given that the instruction can be adapted to meet the needs of the individual.


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 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



Hunt, N., & Marshall, K. (2006). Exceptional children and youth. Boston, MA: Houghton Mifflin.

Turnbull, A., Turnbull, R., & Wehmeyer, M. L. (2007). Exceptional lives. Special education in today's schools. Upper Saddle River, NJ: Pearson Merrill Prentice Hall.

Fey, M.E., Warren, S.F., Brady, N., Finestack, L.H., Bredin-Oja, S. L., Fairchild, M., Sokol, S., & Yoder, P. J. (2006). Early effects of responsivity education/prelinguistic milieu teaching for children with developmental delays and their parents. Journal of Speech, Language, and Hearing Research. 49, 526-547.


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