24 mildly handicapped students were taught two 9-digit numbers in a cross-over design in which number of digits and order of presentation of condition were counterbalanced. In the cluster-rehearsal condition, students were taught the digit series in clusters of three with overt experimenter-led rehearsal. In the mnemonic condition, numbers were transformed into isomorphic pictorial representations of concrete objects and pictured as appearing on the head, hand, and foot of a man, woman, and child, respectively, in each of three pictures. Free and cued recall scores were collected on immediate and three delayed recall intervals, and scored for position, sequence, and span scores. Recall data were obscured by ceiling effects but consistently favored mnemonic instruction. Cued recall scores collapsed across recall intervals statistically favored mnemonic instruction according to nonparametric tests. In addition, as in previous investigations of mnemonic instructions, response latencies were significantly greater under mnemonic instruction. Finally, collapsed item-position scores showed bowed serial-position curves in cluster-rehearsal but not mnemonic conditions. Implications for further research are given.
