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Mental Retardation

  1. Laraine Masters Glidden

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0540

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

Glidden, L. M. 2010. Mental Retardation. Corsini Encyclopedia of Psychology. 1–3.

Author Information

  1. St. Mary's College of Maryland

Publication History

  1. Published Online: 30 JAN 2010


Mental retardation, also known as intellectual disability, is characterized by subaverage general intellectual functioning and impairments in adaptive behavior, both manifested during the developmental years of childhood and adolescence (American Association on Mental Retardation, 2002; American Psychiatric Association, 2000). Intellectual functioning is measured by the Intelligence Quotient (IQ), and, in most instances, an IQ score of lower than 70 meets the criterion for subaverage general intellectual functioning. Definitions of adaptive behavior usually include skills of communication, socialization, and daily living as well as gross and fine motor abilities. Both IQ and adaptive behavior tests are available, have satisfactory reliability and validity, and yield scores that compare individuals with others of the same age. Nevertheless, controversy about their measurement exists, and some critics believe that essential components of intellectual functioning are complex, multidimensional, and not adequately measured by current instruments (Switzky & Greenspan, 2006).


  • intellectual disability;
  • genetic and environmental etiology;
  • early intervention;
  • inclusion;
  • family and community supports