Abstract
The distance of an object from the observer and the size of its visual angle (projected size) are inversely correlated: as the distance of the object increases/decreases, its visual angle decreases/increases correspondingly. However, usually approximate size constancy prevails, that is, perceived sizes of objects are not strongly correlated with their distances. Here I report a curious case in which distance and perceived size of an object are directly correlated, that is, as the distance of the object increases/decreases, its perceived size tends to increase/decrease as well. The object in question is a church in Belgrade, Serbia, which can be observed from increasing distances first along a 400 meter street leading directly to it, then across a square at the other end of the street, and finally along an avenue for about 1000 meters. The phenomenon in question is that as one moves or drives along the avenue away from / towards the church, the church seems to grow larger/smaller. No formal experiment was performed but about a dozen people confirmed to the author the existence of the effect, once they were alerted to it. Photographs taken at various locations along the avenue and corresponding geometrical analyses revealed that as the observer distance from the church increases/decreases when moving along the avenue, its projected size increases/decreases relative to projected sizes of two hotel buildings located at the square, which flank the church as seen through the avenue corridor. Although separated by 400 meters in depth, when viewed from the avenue the church and the hotels are visually adjacent, and are perceived as being near each other in space. In such circumstances size judgments may be based on comparisons of visual angles of adjacent buildings. The phenomenon thus seems to be in accord with Gogel's equidistance principle and Rock's relative size principle.
Meeting abstract presented at VSS 2016