The time course of initial scene processing for eye movement guidance in natural scene search.

A brief glimpse of a scene is sufficient to comprehend its gist. Does information available from a brief glimpse also support further scene exploration? In five experiments, we investigated the role of initial scene processing on eye movement guidance for visual search in scenes. We used the flash-preview moving-window paradigm to separate the duration of the initial scene glimpse from subsequent search. By varying scene preview durations, we found that a 75-ms preview was sufficient to lead to increased search benefits compared to a no-preview control. Search efficiency was further increased by inserting additional scene-target integration time before search initiation: Reducing preview durations to as little as 50 ms led to search benefits only when combined with prolonged integration time. We therefore propose that both initial scene presentation duration and scene-target integration time are crucial for establishing contextual guidance in complex, naturalistic scenes. The present findings show that fast scene processing is not limited to activating gist. Instead, scene representations generated from a brief scene glimpse can also provide sufficient information to guide gaze during object search as long as enough time is available to integrate the initial scene representation.