Ninety junior high school students learned 30 word list composed of 6 categories of 5 words each. Can the first, the fourth and the sixth trial, all Ss were given a study-recall task, while on the second, the third and the fifth trial the Ss in Recall group were given a study-recall task, the Ss in Rehearsal group a study-rehearsal task and the Ss in Control group a study task and the neutral task (cancellation task). Re suits were analyzed in terms of the number of recalled items and the index of clustering (IC) on the fourth, the sixth trial, indicating that Rehearsal group was superior to Control group on either recall or clustering. However Recall group was superior to Control group on recall, but not on clustering.