Four experiments were conducted on the effects of interpolated activity on retention of digits and of specific kinesthetic events. Experiment I replicated Posner and Rossman's finding that short-term forgetting of digits is an increasing function of the size of the information-reducing transform in the interpolated task. Experiment II confirmed Posner and Konick's finding that short-term memory for a specific kinesthetic event does not depend on digital information-processing capacity available during the retention interval. Experiment III showed that kinesthetic recall can be interfered with by interpolated kinesthetic activity; and in Exp. IV, kinesthetic activity interfered with the recall of digits only when the interpolated task involved an information transform of the condensation type. It was concluded that as with shortterm memory for verbal responses, kinesthetic recall is subject to interference, but that the two types of retention may be differentially sensitive to similarity and difficulty effects. The evidence is consistent with the view that these two memory systems are based on independent neural-behavioral mechanisms.