Abstract
Attention capture effects are generally attenuated as stimuli are presented further from fovea (Carrasco & Yeshurun, 1998). However, the nature of this effect has not been characterized across different types of stimulus changes. In the current study, we used a singleton array (solid black circles on a white background) to determine whether change detection varies as a function of stimulus onsets or offsets and sizes at several visual eccentricities (10°, 20°, and 30°) using a flicker paradigm. Participants responded via button-press whether they detected a change or not. It was hypothesized that as stimulus size increased, from 1° to 2.5° in increments of .5°, participants would respond faster to a change. It was also expected that responses to onsets would be significantly quicker than offsets. Trials with no change were included to measure response accuracy. There were significant main effects of change type and eccentricity (all p <.001); participants responded significantly faster to onset than to offset changes (~106ms) and as eccentricity increased, participants spent more time to respond to a change. A significant change type x eccentricity interaction (p <.001) indicated that participants took longer responding to onsets at 30° than at 10°, and this difference was greater in offset trials. Analysis of accuracy data revealed a main effect for change type (p <.001) such that participants detected onsets correctly more often than offsets. Our data suggest that the ability to detect changes in the environment not only degrades with distance from the fovea, but is sensitive to the type of change to be detected.
Meeting abstract presented at VSS 2014