Effects of preferred stimuli on the free recall of moderately and severely mentally retarded children.

The effects of two types of stimuli, preferred and nonpreferred, on the free recall and clustering of 16 moderately and severely retarded public-school children were investigated. An empirical determination was made as to whether to classify a particular conceptual category of stimuli as preferred or nonpreferred. All subjects were presented with 18 objects from 6 conceptual categories in blocked condition. Both the preferred and nonpreferred stimuli were given to each subject in a counterbalanced order using a repeated measures design. Our major finding was that the use of preferred stimuli had a significant facilitating effect on recall but not clustering.