The effect of environmental stimulation upon the stereotyped behavior of autistic children.

Two groups of three autistic children, equated for chronological age but differing in IQ and performance MA, were observed for 20-minute sessions. Total duration of time subjects engaged in stereotyped behavior was recorded for each minute. During minutes 6--15, subjects were provided with either minimal or high environmental stimulation. High environmental stimulation was found to increase the mean duration of time the low-IQ group engaged in stereotyped behavior but to decrease the duration for the high-IQ group. The theoretical implications are discussed.