Abstract
Onset type stimuli have been shown to capture attention in conditions where other singletons fail to do so, such as when the attentional set is not adjusted to monitoring for onsets. As such, onsets have been considered to be uniquely robust in capturing attention. However, looming stimuli have been shown to similarly capture attention, possibly because both are dynamic stimuli that represent some need for behavioral urgency. In our experiments, participants completed a visual search task for a target oval among spheres and made an orientation judgement (set size 4 or 6). One object (target or distractor) either loomed or onset. Singleton type was blocked. Looming was generated via apparent motion, followed by the target replacing a distractor sphere after motion was completed. The onset singleton occurred when the target array was displayed. In Experiment 1, we found a response time cost between distractor and target singletons, reflecting attention capture. Additionally, participants were faster responding to looming targets and slower for looming distractors compared to similar onset stimuli. To account for onset effects possibly being related to the simultaneous presentation of the onset and the target display, in Experiment 2 we examined only onsets at 3 temporal delays (60, 120, 200ms). We found higher response time differences for onsets occurring earlier in the sequence, suggesting that the strongest test between the stimulus types would be onsets occurring prior to the target onset, which we tested in Experiment 3. We found participants were faster responding to looming targets and slower in responding to looming distractors at the highest set size only. These results suggest onsets may be just one type of a small group of stimuli possessing strong attentional capture signals. Future work will examine the influence of attentional set to determine if these dynamic singletons are comparable in capturing attention.
Meeting abstract presented at VSS 2017