Quantifying resource sharing in working memory

Abstract

Several models of working memory (WM), the cognitive system devoted to the temporary maintenance of a small amount of information in view of its treatment, assume that these two functions of storage and processing share a common and limited resource. However, the predictions issued from these models concerning this resource-sharing remain usually qualitative, and at which precise extent these functions are affected by their concurrent implementation remains undecided. The aim of the present study was to quantify this resource sharing by expressing storage and processing performance during a complex span task in terms of the proportion of the highest level of performance each participant was able to reach (i.e., their span) in each component when performed in isolation. Two experiments demonstrated that, despite substantial dual-task decrements, participants managed to preserve half or more of their best performance in both components, testifying for a remarkable robustness of the human cognitive system. The implications of these results for the main WM models are discussed.

Keywords: Dual-task performance; Working memory.

Fig. 1

Illustration of the single memorization of letters task (a), single parity judgment task (b), and the dual task (c) in both experiments. The participants were instructed to fixate on the circle and diamond placeholders during the single tasks

Fig. 2

Distribution of participants as a function of their processing and storage scores in percentage of their span performance for Experiment 1 (blue dots) and Experiment 2 (red dots). The black diagonal corresponds to a sum of 100. The dotted diagonal materializes what would be the equality between the two scores. (Color figure online)