There are three major criteria for intellectual disability: significant
limitations in intellectual functioning, significant limitations in adaptive
behavior, and onset before the age of 18. Other tests determine limitations in
adaptive behavior, which covers three types of skills: 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 avoid being victimized
Practical skills—activities of daily living (person.al care), occupational
skills, healthcare, travel/transportation, schedules/routines, safety,
use of money, use of the telephone.