Learned and cued distractor rejection for multiple features in visual search.

Ignoring distracting information is critical for effective visual search. When individuals are cued to ignore a stimulus, they first attend the to-be-ignored stimulus before learning to reject it. Individuals can learn to overcome the initial distraction produced by the explicit cues, although this cued distractor rejection appears for only one distractor feature. Multiple distractor colors cannot be rejected effectively, even with extensive experience. We asked if this apparent limit on distractor rejection was caused by a restriction on the number of different features (i.e., colors) that could be learned and rejected as distractors. To explore this potential capacity limitation, we asked if attention can learn to reject the smallest possible number of multiple distractors, namely, two. In four experiments examining cued distractor rejection, individuals searched through heterogeneously colored arrays containing reliable, non-target color information. In Experiments 1 and 2, we explicitly cued individuals with which of two colors (both colors in Experiment 1 or one color in Experiment 2) could be safely ignored. Cued distractors were not reliably rejected, replicating previous findings. Additionally, in Experiment 2, we presented a to-be-ignored color without explicit cues and we found that these "uncued" distractors were reliably rejected. In Experiments 3 and 4, we presented the to-be-ignored color information without explicit cues; individuals learned to reliably ignore multiple distractor colors without explicit cueing. These results suggest that learned distractor rejection is better suited to experience-driven learning than explicitly cued distractor learning: Explicit cueing reliably interferes with learned distractor rejection.