Cookies and What-you-see-is-what-you-get

Jean Piaget noticed in 1920 that children often fail to distinguish between perception of an object and the object's actual properties. When a two-year old child sees her playmate leave the room, and then sees and adult remove a cookie from a cookie jar and hide it in a drawer, she expects that her playmate will later look for the cookie in the drawer - despite the fact that her playmate was not in the room when the adult moved the cookie to the drawer from the jar. Why? Because the two-year old child knows the cookie is in the drawer and thus expects that everyone else knows this as well. Without a distinction between things in the world and things in the mind, the child cannot understand how different minds can contain different things. Piaget concluded that "the child is a realist in its thought" and that "its progress consists in riddling itself of this initial realism." Children come to realize that perceptions are merely points of view, that what they see is not necessarily what there is, and that two people may thus have different perceptions of or beliefs about the same thing.

Q: Are you aware of different perceptions?

Source: Stumbling on happiness, 2007.