How does running memory span work?

Abstract

In running memory span, a list ends unpredictably, and the last few items are to be recalled. This task is of increasing importance in recent research. We argue that there are two very different strategies for performing running span tasks: a low-effort strategy in which items are passively held until the list ends, when retrieval into a capacity-limited store takes place; and a higher-effort strategy in which working memory is continually updated using rehearsal processes during the list presentation. In two experiments, we examine the roles of these two strategies and the consequences of two types of interference.

Figure 1

Simple hypothetical predictions of performance by serial position under different combinations of interference from subsequent items in the list, or input interference (InpInt), and interference from the participant’s own responses, or output interference (OutInt). The values of InpInt and OutInt refer to the amount deducted from the proportion correct for every item intervening between the presentation of an item and the appropriate time of recall of that item.

Figure 2

Proportion Correct with fast presentation rate (top) and slow presentation rate (bottom) in Experiment 1. Error bars represent 95% within-subject confidence intervals (Loftus & Masson, 1994).

Figure 3

Proportion correct with a fixed recall window (top) and with a participant-determined recall window (bottom). Error bars represent 95% within-subject confidence intervals (Loftus & Masson, 1994).