Fig 1. The category chain procedure.

(A). Four consecutive trials of the Category Chain task. Each trial presents one stimulus from each of the four categories, but the specific photographs change and the stimulus positions change randomly from one trial to the next. (B). An example of a correct trial. The dashed lines indicate initial touch, and the arrows indicate subsequent touch (neither dashed lines or arrows were visible to subjects). (C-D). Two examples of incorrect trials. In the first case, the initial touch was to the wrong stimulus, so the trial ended immediately. In the second case, the first two responses were correct but the third was incorrect. (E). Two examples each of the four photographic stimulus categories. (F). Two examples each of the four painting stimulus categories.