Diversion of attention changes the appearance of distances as well as of colors. A large frame covered with black cloth stands vertical. Two tiny white disks are held in place on the cloth by invisible threads manipulated behind the frame by the operator. When the disks are set a given distance apart they rest close upon the smooth black ground. The eye sees but two white spots in a free field, and may judge the distance between them without complication. This is done for ten seconds, as with the color disks. Then the spots are covered, and their distance apart slightly changed (or not) by the operator. Again they are shown, and now judged for ten seconds while adding figures. The mental process of addition changes the judgment of the distance.
You will say it is a familiar experience that the road seems longer or shorter as the mind is busy or not. But it is not a familiar thing to determine the law of such lengthening and shortening for definite distances, and under precise mental condition, as in the above experiment.
JUDGMENTS OF TIME.
Every woman knows that color has an effect on the apparent size of objects; that of her dress on her figure.[2] It is not as well known that color affects our judgments of time. Our next experiment examines this matter.
In the diagram on the preceding page the white squares show plainly larger than the black squares.
REVOLVING CHAIR FOR STUDYING LOCALIZATIONS OF SOUNDS.