Learning to Suppress Likely Distractor Locations in Visual Search Is Driven by the Local Distractor Frequency

Salient but task-irrelevant distractors interfere less with visual search when they appear in a display region where distractors have appeared more frequently in the past ("distractor-location probability cuing"). This effect could reflect the (re-)distribution of a global, limited attentional "inhibition resource." Accordingly, changing the frequency of distractor appearance in one display region should also affect the magnitude of interference generated by distractors in a different region. Alternatively, distractor-location learning may reflect a local response (e.g., "habituation") to distractors occurring at a particular location. In this case, the local distractor frequency in one display region should not affect distractor interference in a different region. To decide between these alternatives, we conducted three experiments in which participants searched for an orientation-defined target while ignoring a more salient orientation distractor that occurred more often in one versus another display region. Experiment 1 varied the ratio of distractors appearing in the frequent versus rare regions (60/40-90/10), with a fixed global distractor frequency. The results revealed the probability-cuing effect to increase with increasing probability ratio. In Experiments 2 and 3, one ("test") region was assigned the same local distractor frequency as in one of the conditions of Experiment 1, but a different frequency in the other region-dissociating local from global distractor frequency. Together, the three experiments showed that distractor interference in the test region was not significantly influenced by the frequency in the other region, consistent with purely local learning. We discuss the implications for theories of statistical distractor-location learning. Public Significance Statement We are frequently distracted by salient visual stimuli that are irrelevant to the task at hand. Previous studies have shown that "knowledge" of the location(s) where a distractor is most likely to occur helps the observer to mitigate distraction. In this study, we compared different theories of how the frequency and spatial distribution of distractor occurrence in different locations could influence the ability to avoid distraction. The results favored a local learning account: the ability to avoid distraction by distractors occurring in a particular spatial region is primarily influenced by how often distractors have occurred in that region.