Controlled rehearsal in single-trial free recall

Abstract

Interpretation of data from the overt-rehearsal procedure may be beclouded by item-selection artifacts. To test this hypothesis, a controlled rehearsal procedure was used where to-be-rehearsed items were presented to the subject rather than selected by him. Which items were rehearsed and how many were comparable under the controlled- and the overt-rehearsal conditions. Total recall and the nominal and functional serial-position curves were similar under the two conditions, suggesting that item-selection artifacts could not be too serious. During Session 5 earlier lists were used that the subject had seen under the overt-rehearsal condition, and, using the controlled-rehearsal method, the original rehearsal order was preserved or scrambled. No differences in performance were found. During Session 6 covert rehearsal was compared to the overt rehearsal previously used, and again no differences were found. During Session 7, the rehearsal pattern with the controlled-rehearsal procedure was manipulated and it was found that recall deteriorated when a poor rehearsal pattern was used. These results suggest that a controlled-rehearsal procedure may be useful to study rehearsal processes in free recall, and a strength—decay model was outlined to try to explain the origin of nominal and functional serial—position curves.