Evaluation of 17 children with autism at the ages of 6 to 15 and then again at ages 13 to 25, suggested that, for the majority of people with autism, there may be little development of a theory of mind. For a minority, development may extend to the equivalent of a 3- to 4-year-old level by the teenage years. (JDD)

Forty-nine children (ages 8-17) with mental retardation recognized facial expressions less accurately than did subjects without retardation who were matched on chronological age. Mental age-matched groups showed no differences in accuracy at a younger mental age, but a difference was found at an older mental age. (Author/JDD)

The intellectual model of Jean Piaget asserts that individuals pass through a series of various intellectual stages as they mature. Human development is categorized into four basic stages: (1) sensory motor stage, which lasts from birth to about eighteen months; (2) preoperational stage, lasting from eighteen months to about seven years; (3)…