The importance of being expert: top-down attentional control in visual search with photographs

Two observers looking at the same picture may not see the same thing. To avoid sensory overload, visual information is actively selected for further processing by bottom-up processes, originating within the visual image, and top-down processes, reflecting the motivation and past experiences of the observer. The latter processes could grant categories of significance to the observer a permanent attentional advantage. Nevertheless, evidence for a generalized top-down advantage for specific categories has been limited. In this study, bird and car experts searched for face, car, or bird photographs in a heterogeneous display of photographs of real objects. Bottom-up influences were ruled out by presenting both groups of experts with identical displays. Faces and targets of expertise had a clear advantage over novice targets, indicating a permanent top-down preference for favored categories. A novel type of analysis of reaction times over the visual field suggests that the advantage for expert objects is achieved by broader detection windows, allowing observers to scan greater parts of the visual field for the presence of favored targets during each fixation.