Recovery of information from latent memory stores decreases over time

ABSTRACT

Working memory (WM) performance can be enhanced by an informative cue presented during storage. This effect, termed a retrocue benefit, can be used to explore how observers prioritize information stored in WM. Recent studies have demonstrated that neural representations of task-relevant memoranda are strengthened following a retrocue, suggesting that participants can supplement active memory traces with information from other memory stores. We sought to better understand these additional store(s) by asking whether they are subject to the same temporal degradation seen in active memory representations during storage. We tested this possibility by reconstructing and quantifying representations of remembered positions from EEG activity while varying the interval separating an encoding display and retrocue during a spatial WM task. We observed a significant increase in the quality of location-specific representations following a retrocue, but the magnitude of this benefit was linearly and inversely related to the timing of the retrocue such that later cues yielded smaller increases. This result suggests that participants’ ability to supplement active memory representations with information from additional memory stores is not static: the information maintained in these stores may be subject to temporal degradation, or these stores may become more difficult to access over time.

KEYWORDS:

• Working memory
• selective attention
• EEG

Acknowledgments

Funding for this project was provided by a State University System of Florida startup award to E.F.E. The authors wish to thank Brian Escobar for assistance with data collection.

Author Contributions

A.N. and E.F.E. conceived and designed the experiment. A.N. collected data; A.N. and E.F.E. analyzed data. A.N. and E.F.E. wrote the paper..

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

¹ The end-of-trial epoch from 2500 to 3500 ms encompasses portions of the blank memory delay and recall displays. However, we note that physical stimulation during these periods was virtually identical (Figure 1(c)). Moreover, the recall display contained no additional spatial information that could be used to supplement mnemonic representations of the to-be-recalled disc’s position.

Additional information

Funding

This work was supported by the State University System of Florida startup award.