Self-stimulatory behavior is repetitive, stereotyped, functionally autonomous behavior seen in both normal and developmentally disabled populations, yet no satisfactory theory of its development and major characteristics has previously been offered. We present here a detailed hypothesis of the acquisition and maintenance of self-stimulatory behavior, proposing that the behaviors are operant responses whose reinforcers are automatically produced interoceptive and exteroceptive perceptual consequences. The concept of perceptual stimuli and reinforcers, the durability of self-stimulatory behaviors, the sensory extinction effect, the inverse relationship between self-stimulatory and other behaviors, the blocking effect of self-stimulatory behavior on new learning, and response substitution effects are discussed in terms of the hypothesis. Support for the hypothesis from the areas of sensory reinforcement and sensory deprivation is also reviewed. Psychologists and ethologists, who have been studying these behaviors for some time, have referred to them as "abnormal stereotyped acts," "mannerisms," "motility disturbances," "ritualistic acts," "rhythmic habit patterns," "blindisms," or "autisms" (e.g., Baumeister & Forehand, 1973;Berkson, 1967;Mitchell & Etches, 1977 (Lovaas, Varni, Koegel, & Lorsch, 1977) despite our discouragement of it. Other unexpected and elaborate repertoires also developed during treatment, such as obsession with numbers, compulsive arrangement of letters, and frequent assembly and reassembly of the same jigsaw puzzle (Epstein, Taubman, & Lovaas, 1985). The children who made the largest gains in treatment were also the ones who emerged with the largest repertoire of such "personally contributed" behaviors.To date, no comprehensive theory of self-stimulatory behavior in the developmentally disabled has been proposed. Most theorizing in this area has consisted of unelaborated accounts of specific experimental results, often focusing on body-rock-46 SELF-STIMULATORY BEHAVIOR ing as the "prototypical" self-stimulatory behavior. As a result, Baumeister (1978) found it necessary to create a five-way classification scheme simply to impose some order on the many different accounts, noting that none explained very many findings. The purpose of this paper is to present in some detail the hypothesis that self-stimulatory behavior is operant behavior that is maintained automatically by the reinforcing perceptual stimuli that it produces. This hypothesis will be used to explain the acquisition of representative behaviors and the etiology of self-stimulatory behavior in developmentally disabled persons, as well as certain prominent characteristics of self-stimulatory behavior. Empirical support for this hypothesis is offered from relevant areas of research. The Discussion considers two representative alternative theories and describes implications of our hypothesis for the treatment of developmentally disabled persons and the understanding of apparently related behaviors in other populations.
PERCEPTUAL REINFO...