(10) Size Constancy

Size constancy is the tendency of our minds to perceive the size of a familiar object despite differences in their distance. The size of the image on the retina changes as the distance from the object to the observer changes,

If you observe the following image, you will see how the same man is shown twice (in the very back and towards the front on the right.)The smaller man in the front the same exact size as the man towards the back, he's now just shown at the same elevation as the man in the foreground. However, our visual system will perceive this image as it's meant to be and infer that the man towards the back is farther away, thus making him smaller in the photograph.