Memory-based attentional guidance facilitates visual search through distractor suppression

Information stored in the memory system can affect visual search process. Foreknowing features of distractors could facilitate target selection. Previous studies found that after sufficient practice, participants learned to ignore fixed feature representations in working memory (WM) when they reappeared as distractors. However, varied WM representations would automatically capture attention, suggesting that we could not voluntarily inhibit varied WM representations. Current studies investigated whether active-maintained varied representations could be suppressed as those fixed representations. In study 1, participants were requested to find a specific shape (target) in the search array and indicate the location of a dot inside the target. The fixed color-cue in each trial indicated that target would not be among shapes in the cued color. Meanwhile, there was a constant color, which would never be the target (and never appeared as cue color) during the entire experiment. In negative-cue condition, distractor color in search array was the cue color, while the target color was randomly selected. In constant color condition, distractor color was the constant color which was a long-term memory (LTM) representation. In neutral condition, both target color and distractor color were randomly selected with the restriction that they would never be the cue color nor the constant color. We found that, compared to neutral conditions, both fixed WM representations and LTM representations could facilitate visual search. In study 2, we varied the cue in each trial. Results showed that reaction time (RT) of negative-cue condition was significantly shorter than neutral condition when reaction speed was slow. Importantly, even in fast RT condition, there was no capture effect. In all, our results indicated that participants could voluntarily suppress both fixed and varied WM representations when they reappeared as distractors. However, facilitation of varied representation only happened when cognitive control process had sufficient time to execute.