Abstract
Participants' eye movements were monitored in two visual search experiments that manipulated target-distractor similarity (high vs. low) as well as the availability of distractors for extrafoveal processing (Free-Viewing vs. No-Preview). The influence of the target-distractor similarity by preview manipulation on the distributions of first fixation and second fixation duration was examined by using a survival analysis technique which provided precise estimates of the timing of the first discernible influence of target-distractor similarity on fixation duration. We found a significant influence of target-distractor similarity on first fixation duration in normal visual search (Free Viewing) as early as 26–28 ms from the start of fixation. In contrast, the influence of target-distractor similarity occurred much later (199–233 ms) in the No-Preview condition. The present study also documented robust and fast acting extrafoveal and foveal preview effects. Implications for models of eye-movement control and visual search are discussed.
This research was supported by an NSERC grant to Eyal Reingold. The author is grateful to Gregory Zelinsky, Kyle Cave, Denis Drieghe, Heather Sheridan, and Keith Rayner, for their comments on an earlier draft of this manuscript.
This research was supported by an NSERC grant to Eyal Reingold. The author is grateful to Gregory Zelinsky, Kyle Cave, Denis Drieghe, Heather Sheridan, and Keith Rayner, for their comments on an earlier draft of this manuscript.