Abstract
Visual search involves the matching of visual input to a "search template" – an internal representation of task-relevant information. The present study investigated the contents of the search template during naturalistic visual search, for which low-level features do not reliably distinguish targets from non-targets. Participants were cued to detect people or cars in diverse photographs of real-world scenes. On a subset of trials, the cue was followed by task-irrelevant stimuli in place of scenes, directly followed by a dot that participants were instructed to detect. We hypothesized that stimuli that matched the active search template would capture attention, resulting in faster detection of the dot when presented at the location of a template-matching stimulus. Results revealed attentional capture for silhouettes, but not surface features (color and texture), of the cued category. Silhouettes captured attention irrespective of their orientation (0°, 90°, or 180°). Interestingly, strong capture was observed for silhouettes of category-diagnostic object parts, such as the wheel of a car. Finally, attentional capture was also observed for silhouettes presented at task-irrelevant locations. Together, these results indicate that search for object categories in real-world scenes is mediated by spatially global search templates that consist of view-invariant shape representations of category-diagnostic object parts.
Meeting abstract presented at VSS 2013