Item and Category-Based Attentional Control During Search for Real-World Objects: Can You Find the Pants Among the Pans?

To compare the speed and efficiency of item-based and category-based attentional control during visual search for real-world objects, we measured N2pc components as electrophysiological markers of attentional target selection. In different blocks, participants searched for 1 or 2 specific target objects or for any object in a target category (items of clothing or kitchen objects). Search displays contained 6 line drawings of different objects, and targets always appeared together with 5 distractors from the other object category. The presence of N2pc components to categorically defined targets demonstrated that category-based search can operate at visuoperceptual processing stages. In contrast to previous findings for letter/digit search (Nako, Wu, & Eimer, 2014), target N2pc components were delayed by 40 ms during category-guided search relative to single-target search. This suggests that for objects and object categories that are less familiar than alphanumerical stimuli, category-guided target selection operates less efficiently than selection that is based on a physical match with an attentional template.