Effects of environmental support on overt and covert visuospatial rehearsal

ABSTRACT

People can rehearse to-be-remembered locations either overtly, using eye movements, or covertly, using only shifts of spatial attention. The present study examined whether the effectiveness of these two strategies depends on environmental support for rehearsal. In Experiment 1, when environmental support (i.e., the array of possible locations) was present and participants could engage in overt rehearsal during retention intervals, longer intervals resulted in larger spans, whereas in Experiment 2, when support was present but participants could only engage in covert rehearsal, longer intervals resulted in smaller spans. When environmental support was absent, however, longer retention intervals resulted in smaller memory spans regardless of which rehearsal strategies were available. In Experiment 3, analyses of participants’ eye movements revealed that the presence of support increased participants’ fixations of to-be-remembered target locations more than fixations of non-targets, and that this was associated with better memory performance. Further, although the total time fixating targets increased, individual target fixations were actually briefer. Taken together, the present findings suggest that in the presence of environmental support, overt rehearsal is more effective than covert rehearsal at maintaining to-be-remembered locations in working memory, and that having more time for overt rehearsal can actually increase visuospatial memory spans.

KEYWORDS:

• Visuospatial working memory
• overt rehearsal
• covert rehearsal
• environmental support

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. As described in the Method section, participants in Experiment 3 completed one block with list lengths presented in ascending order and one with list lengths presented in descending order for both task conditions, whereas only an ascending order was used in Experiments 1 and 2. However, a one-way ANOVA conducted using only spans from the ascending task conditions revealed the same significant effect of environmental support, F(1, 23) = 33.6, p < .001,  = .59, seen with data from both orders.

Additional information

Funding

The first two experiments were completed in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Washington University in St. Louis, and supported in part by a Washington University Dissertation Fellowship awarded to the first author.