Mustafa Zeyd Söyük¹, Metin Üngör², Anna Schubö¹; ¹Cognitive Neuroscience of Perception and Action, Department of Psychology, Philipps-University Marburg, Marburg, Germany., ²Associative Learning, Department of Psychology, Philipps-University Marburg, Marburg, Germany.

Visual search is influenced not only by stimulus salience and goal-driven factors but also by prior experience with regularities in the environment. Salient distractors appearing more frequently at certain locations can be suppressed over time, reflecting learned adjustments in the spatial priority map. We tested two key questions: (1) whether the degree of spatial suppression adapts to gradually changing spatial regularities of the distractor, and (2) how prior suppression of a high-probability distractor location affects its later prioritization when it becomes a high-probability target location. Participants performed an additional singleton task in which one location contained a color distractor more frequently than other locations (high- vs. low-probability distractor locations). During acquisition, distractor location ratios gradually increased (2:1 → 4:1 → 8:1; ascending group) or decreased (8:1 → 4:1 → 2:1; descending group). We hypothesized that distractor location learning (DLL) would emerge in both groups, and impact differently on subsequent target location learning (TLL) of the same location now being relevant for the target. Both groups exhibited DLL, but the descending group showed persistent suppression even under weaker ratios. When the previously high-probability distractor location became the high-probability target location, neither group showed TLL, suggesting that prior suppression constrained subsequent upweighting of the same location. These results indicate that the priority map exhibits asymmetric plasticity: down-weighting a location is rapid and persistent, whereas subsequent prioritization is limited.

Acknowledgements: This research was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation – project number 290878970-GRK 2271, project 9).