Figure 1. Experimental design.

(a) Object images were from three broad categories (indicated by dotted lines) with two subcategory exemplars each. (b) Visual and non-visual tasks were performed in separate runs and required maintenance of either visual or non-visual information during the delay period. In both tasks, two objects were presented sequentially followed by a cue, a delay, and a probe image. In the visual task, the probe was a partial object image, and participants indicated whether it came from the cued object. In the non-visual task, the probe was a whole object image, and participants determined whether it was from the same subcategory as the cued object.