Prioritization within visual working memory reflects a flexible focus of attention

When motivated, people can keep nonrecent items in a list active during the presentation of new items, facilitating fast and accurate recall of the earlier items. It has been proposed that this occurs by flexibly orienting attention to a single prioritized list item, thus increasing the amount of attention-based maintenance directed toward this item at the expense of other items. This is manipulated experimentally by associating a single distinct feature with a higher reward value, such as a single red item in a list of black items. These findings may be more parsimoniously explained under a distinctiveness of encoding framework rather than a flexible attention allocation framework. The retrieval advantage for the prioritized list position may be because the incongruent feature stands out in the list perceptually and causes it to become better encoded. Across three visual working memory experiments, we contrast a flexible attention theory against a distinctiveness of encoding theory by manipulating the reward value associated with the incongruent feature. Findings from all three experiments show strong support in favor of the flexible attention theory and no support for the distinctiveness of encoding theory. We also evaluate and find no evidence that strategy use, motivation, or tiredness/fatigue associated with reward value can adequately explain flexible prioritization of attention. Flexible attentional prioritization effects may be best understood under the context of an online attentional refreshing mechanism.