Effects of Rehearsal Strategy on Word Recall

Effects of Rehearsal Strategy on Word Recall

Introduction

Experimenters have examined the role of rehearsal by restricting the amount of rehearsal and requiring participants to engage in articulatory suppression (i.e., continuously repeating a word such as the aloud) during list presentation. The key finding, that the phonological similarity and word length effects are eliminated under articulatory suppression with visually presented items, has been critical in specifying the detailed architecture of the working memory model.

Many formal computational models similarly assume that rehearsal occurs during ISR. Burgess and Hitch's phonological loop model implements rehearsal in the same way as it does serial recall, such that the two processes are equivalent. The primacy model of Page and Norris similarly models rehearsal as a cumulative process and considers rehearsals of list items simply to be more recent re-presentations of these items. They assume that participants rehearse in a cumulative forward order until such a point when rehearsal cannot be completed before the next item is presented. There is empirical evidence that a cumulative forward-order rehearsal strategy can enhance the primacy effect. Palmer and Ornstein (1971) required participants to rehearse items covertly, either cumulatively or in most recent pairs. They found that performance on a subsequent serial probed recall task was strongly affected by participants' rehearsal strategy, with much larger primacy effects being obtained in the cumulative rehearsal conditions (Ricciuti, 1995).

Despite the widespread assumption that rehearsal plays an important role in ISR, it is perhaps surprising that no evidence exists as to which words (if any) participants rehearse. In the present experiment, we therefore sought to investigate directly the patterns of rehearsal in ISR. We used the overt rehearsal methodology, in which participants rehearse aloud during list presentation. Clearly, knowledge of these patterns would enable us to examine directly the assumptions inherent in models of ISR. For example, one could determine whether Page and Norris (1998) are correct in assuming that participants rehearse in a cumulative forward order until they can no longer rehearse the sequence before the next item is presented. In addition, a detailed understanding of rehearsal would allow us to examine any similarities between the mechanisms underpinning rehearsal in ISR and those underpinning recall.

The overt rehearsal method necessitated presentation of the words at a slower rate than is typically used in ISR tasks. To vary the amount of rehearsal that occurred across conditions, we used three presentation rates (fast, medium, and slow). The effect of presentation rate has been shown to be ambiguous. In some cases, a slower presentation rate has led to poorer recall; in other studies, slower presentation rate has led to superior recall. These contradictory findings may perhaps have been due to the two counteracting effects of rehearsal and retention interval: Slower presentation rates are associated with increases in retention interval, but typically also lead to increased rehearsal (which should improve recall). In addition, a silent control group was used in order to determine whether the requirement to rehearse aloud affected ...