How we learn to ignore singleton distractors: Suppressing saliency signals or specific features?

Salient visual information can sometimes capture attention despite our goals, however, there are several ways we can minimize or eliminate such distraction. One such way is learned distractor rejection, in which we increasingly ignore salient, irrelevant distractors across repeated exposures. Here we probe the mechanism underlying this learned rejection. What must be learned about the distractor to promote effective ignoring? Specifically, is feature rejection, alone, sufficient to learn rejection of salient distractors, or do the items’ saliency signals need to also be rejected? To test between these possibilities, we used a modified version of the learned distraction rejection paradigm (Vatterott & Vecera, 2012). Participants viewed training blocks containing either a salient singleton distractor, or a set of three non-salient “tripleton” distractors, followed by test blocks in which the distractor was always a salient color singleton. Critically, the distractors in test blocks always shared a feature (color) with the corresponding training blocks. By comparing attentional capture in the test blocks as a function of the preceding training block we were able to observe whether experience with saliency was necessary for learned distractor rejection. Results revealed unexpected difficulties in replicating learned distractor rejection, suggesting the true effect size may be smaller than initially reported. With respect to our main objective, we found no difference in the rejection of test block distractors based on whether participants had viewed salient or non-salient distractors during training. That is, we found similar attenuation of singleton presence costs in the test blocks regardless of whether they followed singleton or tripleton training blocks. These results show that experience in rejecting saliency signals is not a requirement of learned distractor rejection.