Abstract
Visual search studies typically report unitary search times. Using eyetracking, we divided visual search in naturalistic scenes into three epochs: initiation, scanning, and decision. We manipulated the nature of the target cue (picture or word) and cue lead time, and examined their effects on search time as a whole, and on the three search epochs. Results indicated that scanning and decision times are influenced by the nature of the cue, whereas the time to initiate the search is influenced by cue lead time. A pictorial template facilitates scanning by allowing both faster rejection of fixated distracters and an improved selection of the next fixation. A pictorial template also affects the decision process by enabling faster acceptance of the target. We then examined the role of colour in a target cue. Using the same paradigm, we kept cue lead time constant and manipulated the cue (full-colour picture, grey-scale picture, or word). Search was again more efficient with picture cues, suggesting that template specificity facilitates scanning. Search was also faster with colour than grey-scale picture cues, but this effect was primarily due to faster decision time. Overall, the results suggest that a more specific search template facilitates distracter reject decisions in each non-target fixation, facilitates the selection of the next fixation, and facilitates the accept decision once at the target. Cuing the visual system with the shape of the target plays a particularly important role in real-world search, while cuing the colour plays a somewhat less important role. The results also indicate that eyetracking can be used to better understand the processes underlying visual search.