Intellectual functioning—also called intelligence—refers to general mental capacity, such as learning, reasoning, problem solving, and so on.
One way to measure intellectual functioning is an IQ test.
Generally, an IQ test score of around 70 or as high as 75 indicates a significant limitation in intellectual functioning.
Adaptive behavior is the collection of conceptual, social, and practical skills that are learned and performed
by people in their everyday lives.
- Conceptual skills—language and literacy; money, time, and number concepts; and self-direction.
Social skills—interpersonal skills, social responsibility, self-esteem, gullibility,
naïveté (i.e., wariness), social problem solving, and the ability to follow rules/obey laws and to avoid being victimized.
- Practical skills—activities of daily living (personal care), occupational skills, healthcare, travel/transportation,
schedules/routines, safety, use of money, use of the telephone.
- Standardized tests can also determine limitations in adaptive behavior.
Age of Onset
The condition originates during the developmental period, which is defined as before the age of 22. Intellectual disability is one of several conditions known collectively as developmental disabilities.