Ames Room Illusion

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Visual perception of size is determined with respect to environmental cues such as depth and perspective. The Ames room illusion is proposed to occur due to the manipulation of such environmental cues to produce the visual perception of large size discrepancies between two identical items. The room is trapezoidal in shape, but because it is generally only viewed through a single hole large enough for only one eye, the assumptions made about the dimensions of the room may intrude upon the inferences made about the relative size of the items within it (Gehringer and Engel, 1986). Gehringer and Engel propose that the distorted room illusion (DRI) is due to inadequate perception of the room’s features, which is prevented by the observer’s perspective …show more content…

To test this hypothesis, the researchers devised a restricted head movement (which was assured via a functioning chin rest) and unrestricted head movement condition including both a monocular and binocular viewing condition. The experiment consisted of 144 volunteer participants who either viewed the room both monocularly and binocularly with restricted head movement or with unrestricted head movement. The experiment found that all viewing conditions produced the illusion, but monocular, restricted head movement produced the greatest amount of illusion whereas binocular unrestricted head movement produced the least amount of illusion. That is to say, objects viewed monocularly with restricted movement caused the observers to perceive objects of the same size to be much greater apart in size than if viewed with both eyes and unrestricted head …show more content…

Both objects were equal height and size, but the object on the right was about twice as far away (~60 in) as the object on the left (~30 in). By manipulating visual cues in the environment surrounding the objects, each item is perceived from the observer point of view to be parallel with the other as a result of the dimensional assumptions made about the object’s surrounding environment; because the more distant object depolarizes a smaller angle of photoreceptors on the retina (assumed to be equidistance), it is inferred that the two items cannot be of equal size while remaining parallel with each other due to the angle discrepancy projected onto the retina. This heuristic causes the observer to perceive one object much smaller than the other opposed to each identical object separated by depth. It was hypothesized that due to lack of adequate perception of the manipulated environment, the object on the left (closer) would appear significantly larger than the object on the right (further) while appearing equidistant to the observer based on the angular disparity of the two objects projected on the

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