Ames Demonstrations in Perception

Background

To understand the Ames demonstrations, it is helpful to know the circumstances that contributed to their development. Early in his career, Ames studied law at Harvard University, where one of his influences was philosopher and psychologist William [Page 42]James, a leading proponent of pragmatism. After practicing law only briefly, Ames turned instead to the study of art, and for several years, collaborated with his sister, Blanche Ames Ames, a painter and illustrator whose husband was a scientist. In the process, Ames's interests shifted toward scientific methods of painting more “realistic” scenes, a quest that eventually led him to the study of optical physiology, and, in time, to join the research faculty at Dartmouth College. There, in 1928, he discovered a visual dysfunction he called aniseikonia, a condition in which a person's two retinal images differ enough in size and shape that the brain cannot easily fuse them as one. Some of the Ames demonstrations (which he invented later) may have been prompted by this discovery, partly because those with aniseikonia are susceptible to spatial distortions: Flat surfaces tend to look tilted, rectangles look trapezoidal, and trapezoidal shapes look rectangular.

The Demonstrations

As early as 1934, Ames designed his first “distorted room” in which, from a designated viewing point, trapezoidal walls appear to be slanted rectangles (Figure 1, c-d). His initial room was monocular, requiring that it be viewed through a one-eyed peephole. From that static point of view (and from no others), the space inside appeared to be a conventional room interior, with a checkerboard floor and three visible walls, with a pair of rectangular windows on each.

However, when other components were introduced into the space, the results were astonishing. If two people of the same height stood in opposite corners, one appeared to be tall, the other short; and if they exchanged positions, one appeared to grow, the other to shrink. A ball placed in a wooden trough appeared to roll uphill. Liquid poured from one container to another appeared to be strangely inclined to the side. And if an observer was given a lecturer's pointer and instructed to touch the room's back corners (while looking through the peephole), the result was a baffling sensation in which one's optical reality was at odds with one's kinesthetic reality.

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