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Visual short-term memory (VSTM) is an essential store that creates continuous representations from disjointed visual input. However, severe capacity limits exist, reflecting constraints in supporting brain networks. VSTM performance shows spatial biases predicted by asymmetries in the brain based upon the location of the remembered object. Visual representations are retinotopic, or relative to location of the representation on the retina. It therefore stands to reason that memory performance may also show retinotopic biases. Here, eye position was manipulated to tease apart retinotopic coordinates from spatiotopic coordinates, or location relative to the external world. Memory performance was measured while participants performed a color change-detection task for items presented across the visual field while subjects fixated central or peripheral position. VSTM biases reflected the location of the stimulus on the retina, regardless of where the stimulus appeared on the screen. Therefore, spatial biases occur in retinotopic coordinates in VSTMand suggest a fundamental link between behavioral VSTM measures and visual representations.
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Task set induces dynamic reallocation of resources in visual short-term memory
Successful interaction with the environment requires the ability to flexibly allocate resources to different locations in the visual field. Recent evidence suggests that visual short-term memory (VSTM) resources are distributed asymmetrically across the visual field based upon task demands. Here, we propose that context, rather than the stimulus itself, determines asymmetrical distribution of VSTM resources. To test whether context modulates the reallocation of resources to the right visual field, task set, defined by memory-load, was manipulated to influence visual short-term memory performance. Performance was measured for single-feature objects embedded within predominantly single- or two-feature memory blocks. Therefore, context was varied to determine whether task set directly predicts changes in visual field biases. In accord with the dynamic reallocation of resources hypothesis, task set, rather than aspects of the physical stimulus, drove improvements in performance in the right- visual field. Our results show, for the first time, that preparation for upcoming memory demands directly determines how resources are allocated across the visual field.
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- Award ID(s):
- 1534823
- PAR ID:
- 10026433
- Date Published:
- Journal Name:
- Psychonomic Bulletin & Review
- ISSN:
- 1069-9384
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3758/s13423-016-1181-8
