In psychology, "smaller" refers to the perception of an object as being physically smaller when it is located farther away, even though we know it is actually the same size as a closer object.
Depth perception is the ability to perceive objects in three dimensions and judge their distance from us.
Size Constancy: Size constancy is a perceptual phenomenon that allows us to perceive objects as maintaining their actual size despite changes in distance.
Visual illusions are misleading perceptions that occur when our brains misinterpret visual information, causing us to see things differently than they actually are.