Abstract
Prior knowledge of distractors defined by a basic visual feature elicits faster response times (RTs) compared to unknown distractors. Typically referred to as distractor suppression, the effect does not extinguish when the number of suppressed features increases in a stimulus set. Previously, we demonstrated that category-level knowledge can also elicit distractor suppression with two categories (Goetz & Neider, 2021) but not with three (Goetz & Neider, 2022). In the latter study, the target was a circle placed at a cardinal position adjacent to the object (teddy bears, butterflies, and fish silhouettes). We speculated that Gestalt processing of target and object information may have masked any effects of distractor suppression. In three new experiments, we embedded a target âtâ rotated at intercardinal angles in silhouettes. Participants were instructed that one object category would never be the target. In Experiment 1, we found distractor suppression when two objects were displayed where any of the three categories were presented. Participants (n = 53) were ~92 ms faster to respond on suppress trials than neutral trials (p = .003). In Experiment 2, we increased the display set size to three but only presented two categories (butterfly and teddy bears). With 78 new participants, RTs on suppress trials were ~50 ms faster than neutral trials (p = .03). In both experiments, this was largely due to shorter dwell times on the suppressed distractor compared to the neutral distractor (all ps < .001). However, in Experiment 3 (n = 78), when we increased both the display set size and presented categories to three, we did not find distractor suppression (p = 1.00). These data suggest it may be more efficient to inhibit categorical information when there is less to process in the scene, but a different attentional strategy may be employed in more complex scenes.