How context information and target information guide the eyes from the first epoch of search in real-world scenes.

This study investigated how the visual system utilizes context and task information during the different phases of a visual search task. The specificity of the target template (the picture or the name of the target) and the plausibility of target position in real-world scenes were manipulated orthogonally. Our findings showed that both target template information and guidance of spatial context are utilized to guide eye movements from the beginning of scene inspection. In both search initiation and subsequent scene scanning, the availability of a specific visual template was particularly useful when the spatial context of the scene was misleading and the availability of a reliable scene context facilitated search mainly when the template was abstract. Target verification was affected principally by the level of detail of target template, and was quicker in the case of a picture cue. The results indicate that the visual system can utilize target template guidance and context guidance flexibly from the beginning of scene inspection, depending upon the amount and the quality of the available information supplied by either of these high-level sources. This allows for optimization of oculomotor behavior throughout the different phases of search within a real-world scene.