Pop-out without Attention

Name: Jeffrey Chan

Mentor: Marjan Persuh

Abstract: Pop-out is a visual phenomenon, in which a unique target, embedded among distractor items, is rapidly identified. Because detection of pop-out appears effortless and automatic it has been proposed that pop-out occurs without attention. Experimental evidence however suggests that attention is required to consciously perceive pop-out. On the contrary, strong evidence suggests that grouping, a phenomenon that closely resembles pop-out, occurs without attention. In the proposed project, we will compare pop-out detection with controls that were not included in prior studies. Participants will be required to detect the presence of pop-out in a single task or in combination with an attentionally demanding task. Participants will monitor a rapidly changing stream of letters at the center of display and report the presence of a target letter. During the attentionally demanding task twelve gabors, arranged in an imaginary circle, will be displayed briefly. On half of the trials, one gabor will differ in orientation, causing a visual pop-out. After reporting the target letter, participants will report the presence of pop-out. If pop-out requires attention, performance for pop-out detection should decrease in the presence of attentionally demanding task. Importantly, we will conduct a control experiment, in which only one gabor is displayed. Attention is required for visual perception; comparing performance in a task with a single gabor to a task with multiple gabors will reveal whether attention is required for pop-out itself.