The Perception of Room Size

Three studies were conducted that explore the relationship between the shape and the perceived size of rectangular and square rooms. In each study, subjects were asked to estimate the size of rooms that varied in their ratio of length to width. The results of all three studies indicated a substantial illusion produced by rectangularity; more rectangular rooms consistently were estimated as larger than less rectangular rooms of equal size. This effect was independent of the viewing position of the observer. The implications of this illusion for room design are discussed.