The Functional Significance of Complex Hand Movement Stereotypies in the Severely Retarded

Stereotyped behaviours have been defined as highly consistent and repetitious motor or posturing behaviours, the adaptive consequences of which, if any, are not immediately apparent (Forehand and Baumeister, 1971). As such the term includes a range of topographically dissimilar behaviours such as rocking, swaying, whirling, mouthing, hand weaving and complex hand movements in front of the eyes. Studies from both human and infra-human subjects suggest that these behaviours can enter into complex relationships with subjects' external, and internal (psychophysiological) environments.