Size Constancy

Size constancy is the concept that objects closer to our eyes will produce larger images on the human retina; however, it also states that humans will take distance into account with interpreting size. If one is familiar with the typical size of an object, he/she will consider the constant size and realize that it does not grow or shrink as it moves closer or farther away.

This concept can be demonstrated while standing on the top floor of a skyscraper. When looking down at the city street from this floor, the civilians and cars passing below look like tiny ants, so small that we could easily pick them up. In actuality, however, the viewer recognizes that he/she is observing from afar and objects did not literally shrink. The figures only appear smaller because they are being observed from a distance.  

In this photo example in which I am riding a donkey in Santorini, Greece, the donkey and I look much larger that the cruise ship in the background. However, this is only because the donkey and I were closer to the camera when the picture was taken. In actuality, the cruise ship could hold approximately 10,000 people.