Perceptual Constancies- Size Constancy

Have you ever stood at the base of a really tall building, such as the empire state building, and looked up? It's gigantic, so tall that you almost can't see the top of it. 

Then, as you are walking away, the building gets smaller and smaller, but we know that it stays the same size?

This is Size Constancy. This is our ability to see objects and maintain the notion that they are the same size, even when our distance towards the object make the object appear larger or smaller.

This is seen with all of our senses. For example, when you are going into a bakery. The closer you get to the bakery, the more you can smell the aroma of fresh baked cookies. But as you leave, the smell diminishes. You know the smell is still there, but you just can't smell it anymore.