The Performance Of Visual Working Memory Enhanced By Retrospective Attention Cues

Visual working memory maintains and manipulates a limited set of visual object representations. Because of this highly constrained capacity, it is important that one hold representations of only the most relevant information in visual working memory and remain sensitive to cues from the environment regarding future relevance. A vast literature documents that it is helpful to improve the visual working memory performance in which a valid cue is presented before the memory array, but recent studies have also demonstrated that memory performance can be enhanced by a cue which indicates the item most likely to be subsequently probed, even when that cue is delivered seconds after a memory array is extinguished. We call this cue "the retrospective cue" and the effect that it can improve the memory performance is named "the retro-cue benefit".Although previous studies have proposed that the retro-cue is making a retro-cued item more robust to interference from, or overwriting by, subsequent new stimuli, the mechanisms underlying it remain unclear. Based on these previous studies, we hold the view that the cognitive processing mechanism of the retro-cue is that the retro-cues can modulates maintenance of representations in visual working memory, which let us to maintain only the task-relevant items according to this cues and reduce the impact of memory load, leading to the improvement of VWM performance.What’s more, the retro-cue which can improve the memory performance is spatial retro-cue, whether and why the non-spatial retro-cues can also lead to performance benefits are needed to investigate.In order to verify the viewpoint we mentioned above, this study used ERPs and "the Continuous Report Task" paradigm, through analyzing the contralateral delay activity (CDA) ERP index of VWM load to investigate the cognitive processing mechanism of the spatial retro-cue and the non-spatial retro-cue. The contralateral delay activity (CDA) is the index of VWM load,according to the hypothesis above, at the memory phase, the contralateral delay activity (CDA) ERP index of VWM load would generate when participants selectively encoded memory items from one hemifield, subjects were at a heavy working memory load, but the CDA would attenuate after the spatial retro-cues and the non-spatial retro-cues, the retro-cues make the subjects to maintain only the task-relevant items and relieve the VWM load. The behavior results shows that the VWM performance under the spatial retro-cues condition and the non-spatial retro-cues condition were better than the no retro-cue condition, the ERP results shows that the contralateral delay activity (CDA) ERP index of VWM load generated when participants selectively encoded memory items from one hemifield, subjects were at a heavy working memory load, and the contralateral delay activity (CDA) ERP index of VWM load was attenuated after the spatial retro-cues and the non-spatial retro-cues, reducing the VWM load. what’s more, as the CDA amplitude reflect the memory load, we set up the conditions of the high and low memory load to verify our viewpoint again, the ERP results showed that due to the retro-cue can modulates the VWM load, there was no significant difference in the two CDA amplitude which under the high and low memory load condition. these results further illustrated the cognitive processing mechanism of "the retro-cue benefit" we proposed.Through this study, we got a conclusion which accounts for "the retro-cue benefit". It is that the retro-cue can modulates maintenance of representations in visual working memory, which let us to maintain only the task-relevant items according to this cue and reduce the impact of memory load, leading to the improvement of VWM performance.