I have been babysitting my neighbors for the past 3 years. The girls, Kate and Lizzy, are now 5 and 3 so I have watched them grow up their entire life. I took an intro psych class in high school that taught me the basics about cognitive development. The most fascinating thing I learned was how infants don't understand object permanence. We learned in class that when a child plays hide and seek they think that if they can't see you, you cannot see them. I always thought that was kind of silly until I witnessed it multiple times where little Kate would hide in the middle of the floor and cover her eyes and think I could not see her. Also the shock on a child's face when you hide an object from them and it shows up two seconds later again. They do not grasp the concept of an object being hidden. The experiment that I am looking forward to trying this summer is starting with a glass of water, pouring it into a different shaped glass and seeing if they know that it is the same amount of water. I haven't ever tried this on a child but I know that most children do not understand that it is the same amount of water. Kate and Lizzy are extremely smart for their age but I am curious to find out if Piaget's theories hold true for them.