Intellectual functioning refers to a general mental
capability. It involves the ability to reason, plan, solve
problems, think abstractly, comprehend complex ideas, learn
quickly and learn from experience. Intellectual functioning
is represented by Intelligent Quotient (IQ) scores obtained from
standardized tests given by trained professionals.
Intellectual disability is generally thought to be present if an
individual has an IQ test score of approximately 70 or below.
What is Adaptive Behavior?
Adaptive behavior is the collection of conceptual, social and
practical skills that have been learned by people in order to
function in their everyday lives. Significant limitations
in adaptive behavior impact a person’s daily life and affect his
or her ability to respond to a particular situation or to the
environment. Standardized testing aims to measure the
Conceptual skills: receptive and expressive
language, reading and writing, money concepts, self-direction.
Social skills: interpersonal, responsibility,
self-esteem, follows rules, obeys laws, is not gullible, avoids
Practical skills: personal activities of daily
living such as eating, dressing, mobility and toileting,
instrumental activities of daily living such as preparing
meals, taking medications, using the telephone, managing money,
using transportation and doing housekeeping activities,
occupational skills, maintaining a safe environment.
Intellectual Disability is one of several developmental
disabilities meaning that there is evidence of the disability
during the developmental period of a person’s life. In
California this period of development is defined as
occurring before the age of 18.
Characterized by below-average intellectual function,
intellectual disabilities impact a person’s day-to-day
functioning and last throughout a person’s lifetime. Children
with intellectual disabilities may fail to reach developmental
milestones in their communications, behavior, play, movement, or
learning which will prompt a parent or physician to ask for a
Children with intellectual disabilities may:
sit up, crawl, or walk later than other children
learn to speak later, or not at all
have trouble with fine motor skills
not understand social cues or facial expressions
have trouble solving problems
Generally the more severe the intellectual disability the earlier
it is noticed. Intellectual disabilities manifest themselves
before the age of 18 and generally are lifelong conditions.
Usually, an IQ below 70 falls within the range of Intellectual
It is not precisely known how many people have intellectual and
developmental disabilities but most dependable sources tend to
agree on a range of 1.5% to 2.5% of the total general population.
Based on the most recent US Census, the US population was
reported to be approximately 311 million people which translates
to roughly 4.6 million to 7.7 million people with developmental
disabilities. The number of those who specifically have an
intellectual disability is lower.
The effects of Intellectual Disabilities vary considerably among
people who have them, just as the range of abilities varies
considerably among all people. People with Intellectual
Disabilities may need assistance with communications. They may
need support with self-care and home living. Additionally,
Intellectual Disabilities can effect a person’s social skills and
health and safety, their academic work and professional work
However with appropriate supports over a sustained period, the
life-functioning of the person with Intellectual Disability
generally improves. Appropriate supports includes an array of
services, supportive individuals, and receptive settings that
match an individual’s needs. Every person is different, so each
person with Intellectual Disabilities is evaluated and
reevaluated so that their needs are being met.
For most people supports are needed over an extended period of
time, and for many persons, supports will be lifelong. For some,
however, certain supports may be intermittent or short-term. Most
people with an Intellectual Disability will improve their
functioning with early intervention, appropriate education and
supports as an adult allowing them to live a satisfying,
meaningful, productive, independent, and integrated life in the