Abstract
The surprise capture hypothesis states that surprising or novel stimuli involuntarily attract attention. This has been empirically shown with the unannounced first presentation of a novel color during a visual search task, which eliminated set size effects, improved performance at short display durations, and induced validity effects. Most of these studies presented the novel color as a singleton, either at the position of the target or at the position of a distractor. While there are good reasons to discount the role of singleton capture in these experiments, it seems still desirable to test the surprise capture hypothesis for non-singleton novel stimuli. This was done in the present study by unexpectedly changing the color for half of the stimuli in the last ("critical") trial of a visual search task. To assess the biasing of attention towards the novel non-singleton color, gaze positions were assessed using an EyeLink 1000 eye-tracker. Results reveal that early fixations are more frequently directed to the novel than to the familiar color, indicating that attention is biased towards the novel color. This result shows that a singleton status of the novel color is not a necessary condition for the biasing of attention. This is consistent with the surprise capture account that novelty (or "schema-discrepancy"), if strong enough, is sufficient to bias attention towards the surprising event.
Meeting abstract presented at VSS 2014