Learned Spatial Suppression Is Not Always Proactive

Learning to ignore distractors is critical for navigating the visual world. Research has suggested that a location frequently containing a salient distractor can be suppressed. How does such suppression work? Previous studies provided evidence for proactive suppression, but methodological limitations preclude firm conclusions. We sought to overcome these limitations with a new search-probe paradigm. On search trials, participants searched for a shape oddball target while a salient color singleton distractor frequently appeared in a high-probability location. On randomly interleaved probe trials, participants discriminated the orientation of a tilted bar presented briefly at one of the search locations, allowing us to index the spatial distribution of attention at the moment the search would have begun. Results on search trials replicated previous findings: reduced attentional capture when a salient distractor appeared in the high-probability location. However, critically, probe discrimination was no different at the high-probability and low-probability locations. We increased the incentive to ignore the high-probability location in Experiment 2 and found, strikingly, that probe discrimination accuracy was greater at the high-probability location. These results suggest that the high-probability location was initially selected before being suppressed, consistent with a reactive mechanism. Overall, the accuracy probe procedure demonstrates that learned spatial suppression is not always proactive, even when response time metrics seem consistent with such an inference. Public Significance StatementWe live in a visual world filled with enormous distractions, and the visual system copes with them by suppressing irrelevant information. For example, people may learn to ignore a flashing billboard they drive past every day. The current study examined the underlying mechanism of spatial suppression and showed that participants selected a to-be-ignored location prior to suppressing it, indicating a reactive suppression strategy. These results invite a reinterpretation of how learned spatial suppression takes place and suggest that people may not completely avoid attending to distracting information; instead, they may anticipate where a distractor will appear so that they can rapidly handle it.