Abstract
Previous studies have shown that attention influences the transfer of perceptual representations into visual short-term memory (VSTM). Two recent studies (Schmidt et al., 2002; Woodman et al., 2003) used spatial cuing in a change detection task to demonstrate that spatial cues biased the transfer of objects into VSTM. However, both studies used post-cues that appeared shortly after the offset of the memory array (0ms or 50ms), which could affect the transfer of objects into VSTM but not affect selection of objects already stored in VSTM. To determine if spatial cues can select objects already stored in VSTM, we used post-cues that appeared either 50ms or 650ms after the offset of a memory array that contained 6 objects. We confirmed that immediate post-cues were as effective as pre-cues in transferring objects into VSTM; cued objects were recalled more accurately than uncued objects. We then compared short-delay postcues (50ms after the memory array) with long-delay postcues (650ms after the memory array); cued objects were recalled more accurately than uncued objects for the short-delay postcues only, suggesting that spatial cues affect transfer into VSTM but not selection of objects stored in VSTM when VSTM is filled to the capacity. However, we find that objects can be selected from VSTM when VSTM is not filled to the capacity. Our results suggest that attention affects both transfer into and selection from VSTM and that these effects depend on the timing of postcues and the number of objects stored in VSTM.
We thank Steven J. Luck and Andrew Hollingworth for their helpful comments.