Display of the stimulus presentation method for the Whole Class Tests. All three stimuli in a class were presented together at the same time in one choice box while the other choice box presented a mixture of stimuli from the two remaining classes or stimuli across all three classes. No sample stimulus indicated which choice box was correct. In Test 1, the stimuli were presented together in a box in the order of sign, colored disk, and geometrical form, from left to right. In Test 2, the stimuli appeared together in random order. Notice that the correct stimuli can only be presented in one order in Test 1 whereas there are many permutations of presenting the incorrect stimuli. Similarly, for Test 2, there are many permutations for presenting both the correct and incorrect stimuli, therefore only examples are shown. The bottom two frames show examples of what the screen looked like. The asterisks indicate the correct boxes; this sign was not shown on the monitor.