Task-irrelevant optic flow guides overt attention during visual search

[摘要] It is known that basic visual features such as color or contrast capture attention. Recent research suggests that optic flow also attracts attention even when it is irrelevant to participants' task. However, the impact of an individual's attentional set on attentional capture to optic flow is poorly understood. In two experiments, we examined whether task-irrelevant optic flow induces attentional capture under different conditions of a participant's attentional set. The first experiment aimed to confirm the course of attentional guidance via optic flow in a visual search task. Participants had to find a target, Gabor patch, with an orientation different from distractors. Prior to onset of the search display, a task-irrelevant optic flow display was presented for 1, 3, or 5 sec. Results indicated that all three optic-flow exposure conditions yielded faster search times when the target was presented at the expanding point of optic flow (EPOF) than when the target happened at another location. Moreover, eye movement analysis revealed that the first saccade headed for EPOF. In the second experiment, a task irrelevant color circle, was presented in the search display. This procedure ensured that participants' attention was directed to the color circle which was concurrently presented with a target if participants are sensitive to feature singletons. However, results revealed that the optic flow continued to strongly guide attention. In other words, a color singleton does not override attentional capture created by optic flow. These results suggest that optic flow quickly guides an attention-forward expanding point regardless of participants' attentional set.

[学科分类] 眼科学