No inducement needed: Attention capture occurs without task-induced attention sets

Many dynamic events (e.g., onsets, looming) capture attention even when they are irrelevant to the primary task. Although this result suggests the automatic capture of attention, the demands of the task might actually induce an attention set for dynamic events that underlies capture. Because subjects must wait for the appearance of a display in order to start searching, they might form an attentional set for object appearances or for dynamic events in general. If so, then capture might not be stimulus-driven. In one experiment supporting this conclusion, an irrelevant red pre-cue captured attention only when the search display happened to be red, even though the color of the search display was also irrelevant (Gibson & Kelsey, 1998). The red pre-cue presumably captured because observers were waiting for a red search display. All prior evidence for attention capture by dynamic events is subject to the critique that the task induced an attentional set. We eliminate the possibility of such task-induced attention sets and show that abrupt onsets still capture attention. Method. Two experiments used auditory rather than visual events to signal the start of a search for a target among 2, 4, or 6 distractors. In Experiment 1, subjects closed their eyes after finishing each search. The display changed, and a tone signaled them to open their eyes and begin searching. An onset occurred shortly after their eyes opened. In Experiment 2, the display was present prior to the search, and search began following auditory identification of the target. Results & Conclusion. Both experiments found attention capture, with shallower search slopes when the onset validly cued the target position. Task-induced attentional sets cannot explain these results, suggesting that onsets can capture attention in a stimulus-driven manner.