Reducing failures of working memory with performance feedback

Abstract

Fluctuations in attentional control can lead to failures of working memory (WM), in which the subject is no better than chance at reporting items from a recent display. In three experiments, we used a whole-report measure of visual WM to examine the impact of feedback on the rate of failures. In each experiment, subjects remembered an array of colored items across a blank delay, and then reported the identity of items using a whole-report procedure. In Experiment 1, we gave subjects simple feedback about the number of items they correctly identified at the end of each trial. In Experiment 2, we gave subjects additional information about the cumulative number of items correctly identified within each block. Finally, in Experiment 3, we gave subjects weighted feedback in which poor trials resulted in lost points and consistent successful performance received "streak" points. Surprisingly, simple feedback (Exp. 1) was ineffective at improving average performance or decreasing the rate of poor-performance trials. Simple cumulative feedback (Exp. 2) modestly decreased poor-performance trials (by 7 %). Weighted feedback produced the greatest benefits, decreasing the frequency of poor-performance trials by 28 % relative to baseline performance. This set of results demonstrates the usefulness of whole-report WM measures for investigating the effects of feedback on WM performance. Further, we showed that only a feedback structure that specifically discouraged lapses using negative feedback led to large reductions in WM failures.

Keywords: Cognitive and attentional control; Feedback; Visual working memory.

Figure 1. Task illustration

(A) Sequence of events for each trial. (B) Example feedback screen for each Experiment.

Figure 2. Distributions of performance across experiments

Dotted lines represent performance in the feedback condition, solid lines represent performance in the no-feedback condition in (a) Experiment 1, (b) Experiment 2, and (c) Experiment 3. All error bars represent standard error of the mean.

Figure 3. Average change in performance between the no-feedback and feedback conditions

(a) Change in the mean number of items correct. (b) Percent change in the prevalence of good-performance trials in the feedback condition relative to prevalence in the no-feedback condition. (c) Percent change in the prevalence of poor-performance trials in the feedback condition relative to relative to prevalence in the no-feedback condition. All error bars represent standard error of the mean.

Figure 4. Change in lapse rate for individual subjects in Experiment 3

(a) Proportion of lapses (x-axis) is shown for individual subjects. Subjects are sorted on the y-axis by their overall performance in the no-feedback condition. White bars and black outlines depict the proportion of lapses in the no-feedback condition, and shaded bars represent proportion of lapses in the feedback condition. Thus, if lapse rate is reduced in the feedback condition, the corresponding bar appears white on the right-hand side. If lapse rate is not reduced, then the corresponding bar is entirely shaded. Subjects in both the top and bottom of the overall performance distribution show a large reduction of lapses in the feedback condition relative to baseline lapse rates. (b) The change in lapse rate across conditions is correlated with overall task performance, likely because high-performing subjects have lapse rates near floor in both conditions.

Figure 5. Proportion of lapse trials (0 or 1 correct) over each block of Experiment 3

Black bars represent blocks in the no-feedback condition; gray bars represent blocks in the feedback condition. The left panel shows the group of subjects who received no feedback first; the right panel shows the group of subjects who received feedback first. The dotted line shows the average lapse rate for blocks 2–5 during the no-feedback condition in the left panel.