Figure 3.

Natural versus void viewing conditions and the result of dichoptic presentation, under illumination with middle-wave light only. When patch no. 2 is isolated from the rest of the Mondrian (Right), it appears brighter than when viewed as part of the Mondrian (Left). This demonstration of our dichoptic presentations is not as good as are the true laboratory conditions, but it still works. By using a reduction tube, make sure your right eye can see only the isolated patch on the right part of the figure, whereas your left eye can see only the Mondrian on the left part of the figure. Observe the difference in brightness between the two identical patches. Now cross your eyes so that the isolated patch is superimposed on the Mondrian and compare again. Although the two no. 2 patches are identical and perceived on a common Mondrian background, they still appear very different.