Seah Chang¹ (), Julie D. Golomb²; ¹Ajou University, ²The Ohio State University

It has been shown that observers can learn to suppress a spatial location that frequently contains a salient singleton distractor, which is referred to as learned spatial suppression. Previous studies have primarily focused on spatial suppression in two-dimensions (2D), however, we live in a three-dimensional (3D) world where visual stimuli appear across multiple depth planes. Is suppression learned in a representation of space that includes depth information? In the current study, participants searched six items for a shape oddball target (e.g., a diamond among circles) while ignoring a salient color singleton distractor that appeared on some trials (singleton-present trials). The six search items appeared either in front of (near disparity) or behind (far disparity) the fixation plane (a fixation square presented at the center of the screen at the middle position in depth). In Experiment 1, the salient color distractor appeared more frequently in one specific high-probability location, defined in 3D. I.e., one of the six locations in either the front or back depth plane contained the salient distractor on 54.17% of trials (depth-matched high-probability location). The salient distractor appeared less frequently (4.17%) at the other locations, including the same 2D location in the other depth plane (depth-mismatched high-probability location), other locations in the same depth plane (depth-matched low-probability locations), and other locations in the other depth plane (depth-mismatched low-probability locations). In Experiment 2, each depth plane had its own, different high-probability location, resulting in two high-probability locations in 2D. The results from both experiments consistently showed evidence for depth-invariant suppression: the suppression effect (reduced attentional capture by a salient distractor in high-probability locations compared to low-probability locations) was observed for both the depth-matched and depth-mismatched locations. These results suggest that learned spatial suppression operates on 2D representations, despite the 3D nature of our visual environment.

Acknowledgements: NIH R01-EY025648 (JG), NSF 1848939 (JG), Ajou University (SC)