Abstract
Groups of mentally retarded and nonretarded adults of a similar chronological age attempted to recall a movement of a particular duration after either an unfilled or filled retention interval. The finding that both the retarded and nonretarded subjects failed to benefit from an opportunity to mentally rehearse their criterion movement over the retention interval indicates that strategic differences between the groups cannot explain the poorer performances of the retarded subjects. Other findings indicate that retarded adults may have problems remembering the sensory consequences of a movement, and that their memory for movement duration is more affected by movement context than is the memory of nonretarded subjects.