Overconstancy

Overconstancy is a visual effect that has been noted when viewing a target object from different distances and refers to the human tendency to overestimate the size of a viewed target object when seen from a distance. This phenomenon refers only to size and distance of objects viewed in the natural world. This explains why it is so difficult to accurately estimate distances between objects or between yourself and a distant object. The opposite effect of overconstancy is called underconstancy.