Body-rocking and other habits of college students and persons with mental retardation

Prevalence of body-rocking in college students was assessed, and the charac teristics of body-rocking of college students were compared to those of ind ividuals with mental retardation. For college students, the prevalence depe nded on the restrictiveness of the method used and varied between 3% and 25 %. Video samples showed that when compared with college students, a greater proportion of people with mental retardation engage in body-rocking, seem less sensitive to situational factors, demonstrate atypical collateral beha viors, engage in less leg-kicking, and execute their body-rocking with larg er amplitudes. There were no differences in duration or number of individua l rocks or bouts of body-rocking. We conclude that body-rocking is a "norma l" behavior whose form of expression may become atypical.