Abstract
When faced with relevant and irrelevant information, attention can act as a "bouncer in brain", letting in important information while filtering out distractors. However, when all items are relevant, attention may also act as a dial, adjusting the relative priority of each item. For example, it has been demonstrated using feature based attention that the more importance placed upon an item, the more precisely it is encoded into working memory (WM). However, it is unknown whether this attentional prioritization reflects target enhancement, distractor suppression, or both. In the current study, we examined whether manipulating the attentional prioritization of one shape over another (i.e., circles versus squares) would affect event-related potentials of target and distractor processing: the distractor positivity (Pd) and the target negativity (Nt). Participants completed a visual WM task for two coloured shapes, and the likelihood that one shape would be probed over the other was manipulated. In the 100% likelihood blocks, participants could either be presented with two target shapes (50% attentional allocation to each shape), or one target and one distractor (100% prioritization of the target), while in the remaining blocks one item was probed 75% of the time. It was found that the Pd and Nt were influenced by attentional prioritization, such that greater distractor suppression was present when the target was prioritized 100% of the time, versus 75 or 50%. We also found the SPCN was affected by attentional prioritization, suggesting differences in WM consolidation as a function of attentional prioritization. Finally, behavioral results suggested that memory performance is associated with the degree to which items were processed as targets or distractors. Thus, neural measures associated with target and distractor processing may reflect the degree to which attention prioritizes items in a multi target array, in addition to reflecting a filtering mechanism.
Meeting abstract presented at VSS 2018