Figure 2.

A schematic of the experimental design showing examples of the variation in the number of sample images and in the distance at which choices were presented. From one to four white squares were displayed in the sample phase. In the Choice phase of the Near condition, one image (and only one, regardless of the number of sample images) was placed in one of the positions immediately adjacent to the target. These positions are marked here by stippled outlines, which were not shown to the birds. The birds were presented only with the white squares. In the Choice phase of the Far condition, there was no sample in the positions immediately adjacent to the target. The combination of one to four samples with Near and Far conditions resulted in a total of eight different conditions.