This paper presents four studies which illustrate the variety of deficits in executive function displayed by individuals with autism. The concept of executive function is used to encompass all the mental operations which are involved in self-reflective and goal-directed behavior. Four forms of executive control are addressed: mental disengagement, coordination of two separate acts into a goal-directed temporal sequence, cognitive flexibility, and planning. The results of the first two studies indicate that subjects with autism are impaired in the processes required for learning behavioral strategies which involve a counter-intuitive or arbitrary association between response and target. The dysfunction may result from "stuck in set" perseveration, recurrent perseveration, or failure to sustain a plan of action in the absence of environmental cues. Results from the third study indicated a deficit in the processes required to shift attention from a salient dimension or category and engage attention upon a previously irrelevant stimulus. Results of the fourth study showed that subjects with autism are unable to find efficient solutions to planning problems which require a depth-first search to anticipate obstacles and the cognitive flexibility to change plans so as to avoid these obstacles. (Contains 21 references.) (JDD)