The Effects of Input Organization and Rehearsal on the Rhythmic Short-Term Memory of Mentally Retarded and Nonretarded Subjects

This study examines the influence of input organization and re hearsal strategies on the performance of a rhythmic imitation task. Subjects were mentally retarded adults and nonretarded individuals matched for chronological age (CA) and mental age (MA) respect ively. Subjects (n=6 in each group) were seen individually, selected from a screening test, and trained prior to the experiment. The rhythmic imitation task contained 24 items, each composed of two four-beat phrases. Results from two 2x3 ANOVAs indicated that there were no differences between retarded and normal groups in overall rhythmic short-term memory. All groups performed significantly better on redundant versus non-redundant rhythmic patterns (p<.025) and on primacy versus receney patterns (p<.ool). Significant interactions were found between groups and conditions of both input organization (p<.00l) and rehearsal (p<.05). Although the need for input organization and rehearsal did affect the memory of all subjects, it had the least effect on the CA-matched nonretarded group. On an interactional basis, the retarded and MA-matched groups performed similarly on tasks measuring both input organization and rehearsal strategies. Future research examining short-term memory on musical versus verbal tasks was strongly suggested.