Goal-driven and bottom-up gaze in an active real-world search task

Mobile eye tracking has become a useful tool in studies of vision and attention in real-world tasks. However, there remains a disconnection between such studies and the laboratory paradigms used by cognitive psychology. In particular, visual search has been studied intensively, but lab search often differs from search in the real world in many respects (e.g., in reality one must walk and move head and eyes to find the target, target and distractors are not equally visible, and objects are frequently occluded). Here, we took a broader view of search behaviour and analyzed the gaze of participants who were asked to walk around within a building, find a room, and then locate a target mailbox. Our aim was to describe the differences in behaviour according to principles of (lab-based) visual search, and we did this by testing the effects of top-down instructions (i.e. having more or less information about where to go) and target saliency (i.e. having a more or less distinctive target to look for). These factors made a difference in a real world context by changing the frequency with which signs and cues in the environment were fixated, and by affecting head and eye movements in the mail-room. Bottom-up saliency had little effect on search time, but our approach revealed how it influenced the coordination of gaze, while still allowing us to make contact with laboratory paradigms.