Effects of clustering instructions and category size on free recall of nonretarded and retarded children.

The effects of category size and instructions to cluster on the free-recall learning of 112 nonretarded and retarded children were assessed. Simultaneously presented lists of 12 pictures composed of 2, 3, or 6 categories were shown for three study-test trials. Instructions to cluster significantly increased recall and cluster scores on a new list for both nonretarded and retarded children. The category-size effect was weak, although it was related to the magnitude of the correlations between organization and recall scores.