Figure 5. Representation of a divided attention task corresponding to that used by Ashby and Gott (1988) with human participants. Here, however, pigeons categorized rectangles depending on whether they were taller than wide or wider than tall. The task required attention to both dimensions of a rectangle. Means of categories A and B are shown in the bottom panel. See Figure 2 and related text in Herbranson, Fremouw, and Shimp (1999) for additional details.