Feature-based filtering determines object-based selection in the attentional boost effect

We investigated the selection mechanisms underlying the attentional boost effect (ABE) in two experiments. Participants performed a modified rapid serial visual presentation (RSVP) task, memorizing background images while detecting a multi-featured target. Experiment 1 compared memory performance for images paired with target-match distractors (sharing one feature with the target) versus target-nonmatch distractors (no shared features). Despite partial feature overlap, target-match distractors conferred no memory advantage relative to target-nonmatch distractors; memory for both was lower than for images paired with the target or baseline. Experiment 2 employed color-color conjunctions to test whether distractors sharing all target features (but arranged differently in space) would enhance memory. Images paired with both-match distractors were remembered significantly better than those paired with other distractors, indicating a boost effect comparable to that of the target. Taken together, these findings indicate that the ABE operates at the object level and is modulated by feature-based filtering. The findings further suggest that temporal selection alone cannot fully account for the ABE; object-based mechanisms must also be considered.